In-Runner VS. Outrunner for Giant Scale Models

[Splummer]

Flying Large Electric Aircraft has been a personal focus for me since 2000. Since that time I have studied, developed, and flown, many many Giant Scale Electrics. During these past years I have assembled or flown dozens of + 3000 watt models with In-Runner Geardrive designs and an equal amount of Outrunner designs. I have learned that both types of motors have a place in Giant Scale. Early in the development (2001-2004) of the giant electrics, geardrive was the way to go, With excellent efficiency and large props. During this period we would from time to time try a new outrunner like AXI or Actro. These motors worked fine, but really had pretty poor efficiency and could only turn a smaller prop than the same wattage geardrive system.

Without a doubt the Neu and the Hacker Geared designs have proven to be some of the most efficient designs on the market.

Hacker has been producing In-Runners since the Mid 90's Many of these motor designs have been used to WIN many world Championships in FAI F5D but these are really different applications than aerobatic models.

At the recent 2007 USA FAI F3A Pattern Nats (Ended Yesterday) A Hacker C50-6.7:1 geared ACRO Competition motor was in Jason Shulmans 1st Place model and Andrew Jesky's 3rd Place Model ( QuiQue was running YS Glow?) During the past 4 USA national Championships Hacker Brushless Geardrives have been used. These FAI models are limited to 11 Lbs, and really not Giant Scale at all.

So Why not develop Larger In-Runner geardrives for Giant Scale? Unfortunately it's not so easy.

1.The Giant models require Large props 22"-36" and are typically flying High-G type maneuvers, that place tremendous loads on the output shaft of geabox, Really strong gearboxes are required and these are costly. These designs will ALWAYS require Disassembly and Lubrication from time to time.

2. The cooling in these models is typically towards the sides of the cowling, not directly behind the spinner. Not a huge problem, but In-runners generate heat from the stator, however areas near center of the stator/rotor must be cooled at the center of the motor, this is tricky.

3. Most of the Currently available Giant Models require significant weight on the firewall (Gas engines are pretty heavy) for proper C/G, Most Geardrives are very light weight. Of course batterys can be moved to the front, but I personnally do not feel it is safe to connect the LiPoly's on a 12S/4000watt system with the prop between my knees!

4. Most Motor/Geardrives are typically more EXPENSIVE to produce, since the motor and geardrive are seperate components with a much higher part count than the Outrunner designs.



Outrunners for Giant Scale Electrics:

For most currently available Giant Scale Electrics conversions The Outrunner seems to be much more practical solution. Although the Outrunner efficiency is typically lower( BUT NOT ALWAYS!). They do offer the following benefits.

1. The NEW generation Outrunners are LARGE and WILL effectively turn larger props just like the Earlier geardrives. Plus, No Gearbox servicing.

2. The inherent outside rotation of the Outrunner rotor allows for many cooling options to be incorporated into the motor design, this makes them great candidates for the Large Cowlings on the Giant scale models.

3. On most of the Large Geardrive Conversions, the batterys must be pushed really far forward. Large Outrunners are heavier and normally allow for the batteries to be located close the the C/G point on the model. Making battery changes and connecting easy and safe.

4. Outrunners are relatively simple to manufacture, with few parts. typically Outrunner can be purchased at lower prices when compared to a similar watt in-runner/geardrive designs.

I look forward to some other points of view on this topic.


Sean Plummer
Hacker Brushless #1
2000,2002,2004, 2006 FAI F5D World Champions
2004,2005,2006, 2007 FAI F3A USA National Champions
2004,2005 FAI F3A European Champion

[blucor basher]

I'm sure there will be a variety of responses (heh) but since we have been working for the last several months on giant scale ARF development, I'll weigh in.

I like the convenience and ruggedness of outrunners, no matter what size we're talking about. For world-class competition, I'm sure geared setups will always make sense, and I'm sure that there will always be a group of sport pilots who like geared setups better - but for the majority of pilots whose time and budget are limited outrunners are obviously attractive.

Personally, I wish we could put the "inrunners are more efficient" debate to bed for good. I think everyone agrees on that point! The reasons to choose outrunners are not for efficiency, but for the other reasons pointed out in the original post. For most pilots I talk to, those are the important factors.

[Jocke]

"Hacker Geared designs have proven to be the most efficient designs on the market"

No you havent, i still cant find any oficial data regarding Hacker efficiency from dyno, yes from 3d part i can get interesting data but not on all type of hacker motor/setups. It has also been hard to get real data on setups, Amp, Temp, Volt, RPM, prop, recomended max amp, burst, max watts and so on. You have had suscess in F3A but that doasen outomaticaly prov the hackers are most efficient.

The way i see it and experience-

Outrunner always less efficient- wrong
Outrunner power weight always havier- wrong

I still dont understand why this subject keeps poping up on the zone !?!? its been debated over and over again without end, to investigate deeper in this has been very interesting... ;)

Feels like i already know how this tread will end :)

[Splummer]

Hi Jocke,

I have been following your posts for years.The way I see it you have tendency to favor outrunner designs for many applications.....

Please do not mis-understand my comments regarding the " most efficient" for Neu and Hacker , Of course many brands of Geared inrunners can be optimized for peak efficiency at a given power level. Plettenberg and lehner also have excellent efficiency for certain aircraft. We (Hacker) has dyno tested many in-runners over the years and found certain combinations to be absolutely more effecient than others. Please keep in mind effeciency really means nothing unless the output of the motor can effectively be used to propel the given type of model.

Jocke- This thread is discussing power systems for GIANT SCALE models, lets not get into any of the lower power type motor designs or efficiencies....

Please carefully read what I stated that "Outrunner efficiency is typically lower (BUT NOT ALWAYS!)". I have used numerous low efficiency outrunners that simply do not work well at all, especially at +2000 watts. I have also used several Brands of Outrunners with very impressive output and effficiency

You claim that the power to weight ratio of Geardrives to Outrunner is the same. Please give me an example of a Large geardrive in-runner type and weight, and please also identify the same exact weight Outrunner that will produce the same output thrust and pitch speed at THE SAME INPUT WATTS.

No dyno charts, just real world power from a Propellor on a model. Also keep in mind this system must be able to operate in real world tempertures, 60-110F (20-45C) on back to back 8-10 min flights. Also be able to operate at typical altitudes sea level to 6000 ft.

-Sean

[Jocke]

I have been following your posts, remember what you said few yaers ago regarding outrunners ;)

Do not wish to start a new war here "mine is bigger than yours!" i guess we have diffrent experience and way of seeing things.

Latest tests shows i have an airframe/setup on 13kg with potential 950w/kg, if i want it can be 12kg 1000w/kg powered by an outrunner ;) if i feel i need even more, no problem!

I often use the DD and outrunner design for my aircrafts to show pepole it works, do i still use inrunners...? yes! sometimes even geared :) but not very often for aerobatic/3D/Pattern/sport/warbirds exept the Pletti Freestyles and in past the HP300 and HP370.

Why dont Hacker show the Dyno result to public on there motors!? you say they are superb... even the best! how can one know if you dont show any data like Plettenberg, Kontronik and others do to prove this?


"you have tendency to favor outrunner designs for many applications..... "

Ofsorce... someone have to defend the outrunners on Ezone with all the geared propaganda floating around;)

[Gerald]

...2. The cooling in these models is typically towards the sides of the cowling, not directly behind the spinner. Not a huge problem, but In-runners generate heat from the center rotor, and therefore must be cooled at the center of the motor, this is tricky.
...Sean, perhaps I don't get your meaning here, but don't 'in-runners' generate most of their heat in the windings, which are at the outer circumference of the motor? This arrangement allows the greatest heat source to be in contact with the case and its cooling fins. This should provide better cooling than that of the windings of an outrunner which are located in the center of the motor.

[Splummer]

Jocke,

Thank you for your responses to this thread.

Re: Dyno data- Due to the prolific cloning of Hacker motors in the past, Mr. Rainer Hacker has chose not to disclose certain propreitory data on his designs.

Re: Past Posts - In my opening post I clearly state that in the period from (2001-2004) the LARGER geardrives totally outperformed any outrunners being produced. TODAY things are clearly different , new ESC options, Larger Outrunners and Better Batteries have all contributed to making Outrunners much more practical for Giant scale models.

Re: Same power / same weight - I have Hundreds of motors at my disposal (Both Geared and Outrunner). In every case I have examined the Geared In-Runner will always produce more thrust and pitch speed than the identical weight outrunner with the same input watts....Please give me the name of an Outrunner that will match the Propellor output of a properly set-up geared in-runner at IDENTICAL WEIGHTS.

Note: I have been looking for this solution for years to no avail, I can match the output of the Geardrives, but in every case the Outrunner is physically HEAVIER by 15-20%.

I do believe the Larger Outrunners at the heavier weight is still the better option for Giant Scale aircraft as previously mentioned ....

-Sean

[Surly_Schmidt]

:cool:

[sneu]

2. The cooling in these models is typically towards the sides of the cowling, not directly behind the spinner. Not a huge problem, but In-runners generate heat from the center rotor, and therefore must be cooled at the center of the motor, this is tricky.



Hi Sean,

I really don't agree with that point. Most all the heat in a inrunner is generated in the stator--iron losses and copper heating. The magnets should not be a heat generating item. If you read the text books on motor design they make the point that inrunners are easier to cool because the stator heat has a direct path to the outside cooling air. Outrunners may often they may seem cool to the touch, are actually much hotter on the inside because the hear generated in the stator has a poor path to the outside.


Steve Neu

[Splummer]

Hey Steve,

Understand your point, guess the wrong words were used. Just because the outside of an In-Runner is cooled , doesn't mean the center areas near the stator/rotor are also being cooled. I am sure this is the reason Neu Motors have added fans to some of your SUPER EFFICIENT In-Runners.

Never said anything about the Outrunner stators being any cooler running than an In-Runner, only that it is easy to get airflow to the stator on an Outrunner.

Sean Plummer
Hacker Brushless #1
2000,2002,2004, 2006 FAI F5D World Champions
2004,2005,2006, 2007 FAI F3A USA National Champions
2004,2005 FAI F3A European Champions

[sneu]

Hey Steve,

Understand your point, guess the wrong words were used. Just because the outside of an In-Runner is cooled , doesn't mean the center areas near the stator/rotor are also being cooled. I am sure this is the reason Neu Motors have added fans to some of your SUPER EFFICIENT In-Runners.

Never said anything about the Outrunner stators being any cooler running than an In-Runner, only that it is easy to get airflow to the stator on an Outrunner.


Hi Sean,
The fans are used to get some air flow through the motor in a attempt to help cool the stator AND to keep the heat being transfered to the rotor. Some of of our motors have air paths through the rotor core for air to pass through. Having said that... with maximum copper fill being the goal with both types and a small air gap also desired there is little room inside the motor for air to cool the stator in both motor types. In our new"H" series motors the fan pulls air from in and it is then directed foward along the outside of the motor case--works very well --check out the pictures here http://www.neumotors.com/20061222/Heli%20Motors.html

Steve Neu

[Splummer]

Steve,

Soooooo.... The point of your post is to CONFIRM what I had earlier stated, that even the most SUPER efficient In-Runners in actual practice, require some airflow or they WILL FAIL as stated in first paragraph of the Neu Motors heli page. Obviously this adds additional mechanical FAN components to Geared In-Runner. Unfortunately, these extra complications add additional costs to the Geared In-Runner solution for High output Giant scale applications.

Here is the direct quote from the Neu Motors Heli Page:

"The lack of cooling and high peak loads in hard 3D flying often leads to very hot motors that fail early"


I have found that the large cowled Giant Scale applications have very stagnant air directly behind the spinner, very similar to the helicopter applications. For this reason it makes perfect sense that Larger Outrunners benefit from simple fans attached to the rotor providing additional airflow through the stator.

-Sean

[sneu]

Steve,

Soooooo.... The point of your post is to CONFIRM what I had earlier stated, that even the most SUPER efficient In-Runners in actual practice, require some airflow or they WILL FAIL as stated in first paragraph of the Neu Motors heli page. Obviously this adds additional mechanical FAN components to Geared In-Runner. Unfortunately, these extra complications add additional costs to the Geared In-Runner solution for High output Giant scale applications.

Here is the direct quote from the Neu Motors Heli Page:

"The lack of cooling and high peak loads in hard 3D flying often leads to very hot motors that fail early"

-Sean


Sean,

Don't try to make conclusions so fast:) Helicopters have different and unique issues. The fan that we use forces air over the outside of the case. Since the stator has a good thermal path to the outside it is logical that the air should be passed over the outside--right? Helicopters while having a nice big fan just above the motor have little cooling as the center of the rotor is a dead zone with little air movement. The fan versions address this and with the greater popularity of hard 3D flying the solutions from last year are not always suitable for today.

Now for airplanes--a cooling fan will allow a smaller motor with less weight and surface area to operate at higher powerlevels without danger of damage from overheating if there is not good airflow from the prop. Yes there are some more parts required but if you want the lightest and highest power possible then there are not too many options. Heavy and large and simple -vs-light and small and more complex. There is a place for both.

Your discussion about why heavy motors are best suited for large scale planes is interesting. Most of the planes I have seen simply fly better when they weigh less. You suggest that it is a advantage for a electric motor to weigh about the same as the gas motor that it replaces as the batteries can be put in the center of the plane to balance it. If heavier planes fit your flying style then good. For me I still like the light weight solutions better. Maybe another possible option is to use a larger battery with the lighter motor and push the battery foward a little to get the CG right--you now have the best of both--heavier model--but with larger batteries for longer flights!

We will not agree on this--but it is fun to discuss it:)

Steve

[Jocke]

"Note: I have been looking for this solution for years to no avail, I can match the output of the Geardrives, but in every case the Outrunner is physically HEAVIER by 15-20%."

Sounds interesting, give me detailes, exactly what motors have you compared and on what setup?.... in the end it all gets silly comparing like this "mine is bigger than yours" , give me an inrunner, max 1,5kg that spinns a prop no larger than 28" 88-90%eff on 12kw power, i want to fly 12min 3D without heat, just changing pack and upp again for 12min in summer heat... see what i mean.. this can go on and on forever.

As Steve said, dont think we will agree on this, instead lets get back to the subject.

One advantage is the cooling of the outrunner design, for exampel the possebility to mount a motor like the Predator with 2-3blade folding props and a spinner sorunding the motor with cooling inletts. Or an integrated fan on back plate of motor, also possibility to backmount the motor for simple installation and nice cooling.

[Jocke]

Exampel.

[Heather]

Re: Dyno data- Due to the prolific cloning of Hacker motors in the past, Mr. Rainer Hacker has chose not to disclose certain propreitory data on his designs.

I struggle to see how Dyno test data can give away design secrets of a motor. Can someone explain how this can be so?

Tests in a model are very subjective. Even Prop data requires that you have the exact same prop and very similar Kv motor to provide a comparison that is meaningfull.

I had a look on the Hacker USA website but could not find even prop data for the A60 & Larger motors. Is it just that I cannot find it or is there none? (By prop data I mean static tests with Amps, Volts & Rpm's at a minimum)

Heather

[Jocke]

I cant see how it could hurt anything with public dyno data, only prov the motors high performance/ eff. Also more data regarding props, and recomended powerlevel of the motors would be nice.

Sean, you have any more info regarding the Hacker A200 15kw motor?

[Splummer]

Jocke,

Thank you for your posts, The issue regarding Dyno Data is up to Mr. Hacker, I do not control his decision on this matter. Your images offer some great advantages to Outrunner for Giant scale . I still don't under stand your explanation regarding Output power Vs. Weight of In-Runner to Outrunner.

It is very clear that at this time period of currently available products for use in Giant Scale models: When the Same Weight Geardrive In-Runner and the Same weight Outrunner are provided the SAME watts input, The Geardrive In-Runner will normally produce MORE Thrust and HIGHER pitch speed.

Jocke-
If You are able to contradict the above statement please do so by providing motor comparisons or brands. I am fascinated to learn about an Outrunner that can go Head to Head with an Geared In-Runner based on Weight/Output. Again, I am a proponent of Large Outrunners, however, I feel it is very important to understand the trade off's when going that route.


Steve,

Thank you for your posts.

I have NEVER said heavier is better, Only that most Outrunners are relatively heavy, this can be used to solve some C/G issues that are often encountered when converting Giant Scale models( It is a real PAIN when the Packs I own must be Located in front of the Prop arc to make C/G !?!?). There is no doubt that lower wing loading is an important consideration on any model, however on GIANT SCALE stuff, even the models that are a little heavy still FLY FINE. For this reason I don't get to wrapped up in micro ounces on planes that are 15 to 50LBS.

Steve-I really enjoy you contributing, to MY threads, I just ask you don't use Your expertise and F5B experience as the PRIMARY basis for Giant Scale power system discussions. I do feel the NEU Motors BAM is the Best example of a Geardrive In-Runner for Larger Giant Models. I am also excited to see your next BIG, BIG motor in action. This is the really fun stuff!!!!

Many of you know my history in Electric Giant scale, I have been setting up and flying Numerous HIGH POWERED 25% models since 2002, 35% models since 2003 and 42% since 2004.

My Goal in starting this thread was to Discuss the Power options and Philosophy behind these options that are currently available to Giant Scale electric enthusiasts.

As always I am looking forward to more interesting info, keep it coming!

BTW: here are a couple pics from the Archive

Best regards,
Sean

[Jocke]

Been trying to answer your questions, but i guess there is a missunderstanding ;) i usaly prefer talking direct tru phone or face to face, maby we can do that in future.

[R/C Dallas]

You guys are silly...just like watching my kids argue over which Pokemon is better then the other! How many years have you guys been at it now? Enough already!!

The bottom line is whether the person is having a fun or not and that's usually indicated by the smile on the pilot's face. I don't think Steve's smile is any bigger than Sean's or Jocke's. All three of you enjoy what you are doing and just have a different way of getting to the same point. Enough with the back and forth "but you said" crap...all of the motor setups can and do produce the same amount of smiles which is what this hobby is all about.

[Splummer]

R/C Dallas,

Silly, I am not sure that the I would consider all responses silly, maybe a little BORING, and not particularly constructive. The beauty of these forums is they allow different points of view. So lets, get on with it.

R/C Dallas- Please give us your views on Geared Vs. Outrunner for Giant Scale applications!

I am feeling a little Nostalgic:
Here are some videos from past Geardrive systems

2002 Twin Geardrive Edge: http://www.rccraze.com/lesebergedge.mpg

2003 Geardrive single 80" Funtana: http://www.rccraze.com/mwefuntana.mpg

2005 Geardrive Twin Extra: http://www.rccraze.com/comparf.mpg

2006 Geardrive Quad: http://www.rccraze.com/marksaefdemo.mpg

-Sean

[airorv]

This thread is exactly what has been needed since electric flight began. I remember so many times asking why the manufacturers are not held accountable for how much power can be converted with a particular system. I understand that there are many variables involved but when I am trying to decide what motor, propeller, battery a model needs I have to play detective to find out if the specs are realistic or optimistic.
I am amazed at how many people fly a very expensive plane for only a few flights before some large financial event.

The reason why I am looking at this thread is that I am always drawn to the larger size planes that I used to fly with glow and gas. I of course like the reliability of electric power but it is not more convenient to keep on buying parts because the system was not robust enough to last. An old Quadra will give you hours and hours of flight time without much cost or maintenance. I want real reliability in giant scale with electric power.

Right now I am flying an Astro brushed system in my large plane because they are quite reliable. I would like to replace it with a new brushless system but I will watch a little while longer. I know, I know, I am in the dark ages, but I like to fly a plane for hundreds of flights not tens.

One more thing. I also agree that I don't like connecting a 40 volt battery pack to a speed control that scares you because of the large spark while your within inches of a 20 inch razor sharp blade. I always make up a safety socket glued into the side of the fuselage.

[feathermerchant]

Sean - I have also been frustrated by the lack of electric specific 50cc and larger planes. Seems like every time I put my Hacker C50XL on a plane it is automatically tail heavy. So it sits unused. I really wish more would at least ARF planes with moveable wings so we can accomodate electric and gas systems more easily. Outrunners do have a farther forward CG then inrunner/gearbox combos. That certainly helps.

Looking at your nostalga pics, I am mentally comparing them to my 3DHobbyshop 85" Katana that weighs only 15lb. Seems light by comparison to some. It is powered by an AXI 5330/28 on 12S. Makes ~3600W and flies great.

I believe that with todays batteries motor efficiency is not as important as it once was.

BTW I echo your cooling comments. The big AXI was coming down ~135deg on a 92deg day. I added one baffle to the cowl, directing air over the motor and now it is so cool I don't even measure it.

[blucor basher]

I'm interested in airorv's comments. Lack of reliability has kept people out of GS electric, but based upon my experiences, it's not the motors that cause this, it's the ESC's. The Castle 110HV looks so promising on paper, but I find that I need to keep a spare one on-hand just to keep three GS planes flying on a regular basis. It seems that paying an extra $100 for a more reliable controller would be wise. On batteries, I haven't had any problems with the 20C Enerland or 25C TP cells, if they are used at 20C max burst. Used over 20C, lifespan is highly variable.

[airorv]

Feather,

You are making my point. You say you know of an AXI 5330/28 running at ~3600 watts. I am assuming you are talking about the 5330/24. AXI website states that motor as a 10s motor that is capable of 65 amps for only 30 seconds. That is about 2300 watts not 3600. I may be wrong but I think smoke is in the future of that one.

Blucor,

I agree, I have had 2 of the high voltage controllers just snap and quit in the last year. Hardly reliable. Every time I plug in my safety jumper, I cringe. Then I look up and say "Thank You".

[rebell]

Obviously you guys have a lot of knowledge and experience and I cannot contribute here. Please allow me to ask a question.

What is the feeling about geared outrunner? I am planning some big scale models and am more interested in big prop efficiency and thrust than speed. Am I "silly" to want to use a geared outrunner for even bigger props? The planes will have really LOW wing loadings.

[airorv]

The gear drive is what most guys don't want to mess with. I have been using gear boxes for a long time and you have to pay attention to them. If you do they work great.

I would think this thread is talking about trading the efficiency of a gear box with the ease of use of the outrunner.

I have a small outrunner that was mated to a planetary gearbox for an electric sailplane. It is a bad combo because I cannot get a large enough propeller with enough pitch. I replaced it with a properly sized direct drive outrunner. Now I don't worry about it.

[blucor basher]

What is the feeling about geared outrunner? I am planning some big scale models and am more interested in big prop efficiency and thrust than speed. Am I "silly" to want to use a geared outrunner for even bigger props? The planes will have really LOW wing loadings.

With larger outrunners available with KV's in the 100-200 range, there might not be any need to gear such motors down any further. Do you have some basic figures - weight, desired prop size, desired battery configuration?

[R/C Dallas]

Sean

The bickering was silly...the info was not. I very much enjoy hearing the opinion of others who have experience with electric flight and seeing the results of their trials and tribulations. Definately what these forums are all about.

As for my opinion, I think I represent the average R/C pilot...I generally fly for fun but am interested in learning precision aerobatics to make me a better pilot. Maybe some small scale competitions down the road but nothing serious. I like the lower cost and convenience of outrunners vs geared inrunners. (please...I have read the many arguments of the outies vs. innies and am quite secure with my decisions) If I was competeing seriously I would surely consider the top of the line geared systems for their lower weight and (on the average) higher effeciency, but right now I stand a better chance of being able to move to giant scale and meeting my needs by using the lower cost motors which are typically outrunners.

To back that statement up...I am currently building a 31% CA Models Extra 300L (Builders kit) and will be powering it with a Hyperion Z5045-18B and Jeti SPIN 99 which I was able to get at a total cost of $395. I love Hobby Lobby and All e R/C sales! I'll be using A123 batteries in 14S2P configuration on an APC 24x12e prop which should give me somewhere around 36-3800watts. Target weight...between 18-19lbs. Not the lightest...not the most powerfull but 165-200w/lb (from the various calcs) should be more than enough to get me where I want to be. Total cost...somewhere in the neighborhood of $1,200-1,400. No way to achieve that with a Neu geared motor unless I was to win it! (Now wouldn't that be sweet!) When you giving one away Steve?

[jrb]

Looks like you can get more out of geared?

Didn't think this was giant, but too hot for an outrunner?

Looking for a geared setup to replace an AXI 4130/20 would like to prop fro 50amp on 6S.

TIA,

Jim

[Jocke]

Gearing a high pole big outrunner could be a problem, they dont like high rpm and are not efficient there togheter with the controler, generaly an outrunner can handle high rpm if its designed for it.

Looking at the biggest out there, big Predator, Cyclon Big Boss and Hacker A200 they should be abul to spin very big props at lower rpm on lover voltage 10-12s Lipo.

Regarding ESC reliability, past 2 or 3 years i have had 5 diffrent Jeti ESC runned on 10-15s Lipo, i have had no issues with them. I do wish all of them would have anti spark feture like the SPIN200, dont like to arm a fresh new 10+s battery witout anti spark feture, quite scary!

-----------------------------------------------------------


"You guys are silly...just like watching my kids argue over which Pokemon is better then the other! How many years have you guys been at it now? Enough already!!

The bottom line is whether the person is having a fun or not and that's usually indicated by the smile on the pilot's face. I don't think Steve's smile is any bigger than Sean's or Jocke's. All three of you enjoy what you are doing and just have a different way of getting to the same point. Enough with the back and forth "but you said" crap...all of the motor setups can and do produce the same amount of smiles which is what this hobby is all about."

I totaly agree with you!


Now lets all hope the weather (spelling?) gets better in this part of europe :)

[Splummer]

R/C Dallas,

Thank you for the post. I am very interested in your system, I have not used the A123 on any Giant Scale applications. I have used them as 7S on a .40 size model (They were Kinda Heavy). I did like the deep discharge ability without immediate cell damage.

Please keep us updated!

-Sean

[sneu]

With larger outrunners available with KV's in the 100-200 range, there might not be any need to gear such motors down any further. Do you have some basic figures - weight, desired prop size, desired battery configuration?

For a given weight the geared motor will be lighter--no if ands or buts and can have a lower effective Kv to the prop. If weight is not a factor then use the cheaper and heavier motor. In the case of motors and power systems less costs more:)

Steve Neu

[rebell]

I want to build some big scale civilian aircraft, so, as mentioned before, speed is not an issue. Since I life in a area where most of the year we get a lot of days where the wind is very calm, weight is not a requirement. Combining this, I can build very light without having problems. Flying a lightweight plane at low speed, drag is also less of a power consumer. The lighter you build, the less power you need and the smaller and lighter the power system need to be, decreasing the weight even further.

Now, if I install a heavy low kV direct drive outrunner, it also needs a lot of cells. Then I must strengthen the airframe, going in the wrong direction with the weight. The cost is then also going up a lot.

I have a few planes in mind but the one I might build first is a 3-metre Caravan. I built a 1-metre Caravan and it really doesn’t need a lot of power. The 3-metre is only done on CAD so far and I don’t want to mention the calculated weight here before I actually built it, you might laugh at me, but I can say it will be VERY LIGHT. Putting a small direct drive outrunner on it, the prop will be to small for scale appearance and enough thrust will only reached at higher rpm. That is why I thought of a small geared outrunner to do the job.

I did not test the combination yet, but used different calculator programs to see what might happen. While I see that the programs are sometimes off by a big margin, I don’t think they are so far of that I cannot go by those figures. I want to use an Axi 2814-12 with a 3:1 gearbox to pull an 18x11 2-blade prop and let the plane fly at scale speeds. Yes, I know there are bigger motors that turn this prop on direct drive, but that is at the cost of weight and amp draw.

The next reason is that I just want to use as small a motor as possible just for the fun of it. Maybe this is the main reason.

[feathermerchant]

FWIW I know that 80A is over what AXI recommends for the motor but
a) I need the weight in the front to make CG
b) My temp samples tell me it is not getting hot
c) We know it unloads in flight. A 10 min flight used ~3,000mAh from the pack so that's about 20A average.

I also know that the amount of cooling has a lot to do with how much power the motor can handle. ie how much heat it can dissipate.

Steve - What is the normal difference in power output possible for a motor of your with and without fan? IOTW what did adding the fan benefit in terms of allowable power output?

I'd say that it would really help me want to by a Hacker or Neu if there were som ereal life setups listed. Even Steve's calculator is not very close. Maybe +/- 10%

[henke]

My 4 year old 80" plane with a geard C50XL still has not been outperformed by anything, And I guess the Hacker Quad is the strogest motor around for a 120" 40% plane. However Sean has a good point in the high forces doing 3D with 30"+ props.

So for giant scale the race between Inrunner and outrunner get´s more even, where the geard system has a bit more power, and the outrunner the simplicity.

And for winning the competition, who cares if the winning motor has 97% or 70% Efficacy, it´s not about dyno runs, it´s about moving air, beeing out there flying.

(The Katana Jocke is flying is the first outrunner powerd plane that impresses me, seem to be light and yet has good power.)

[rcelectfly]

My 4 year old 80" plane with a geard C50XL still has not been outperformed by anything, And I guess the Hacker Quad is the strogest motor around for a 120" 40% plane.

The NeuMotors GBAM does the same thing for a whole lot less money with one motor and one ESC. There are currently two of them flying.

Here is one in a 46% ultimate.

http://www.rcgroups.com/forums/showthread.php?t=688499

Here is information on the test of the motor and controller

http://www.rcgroups.com/forums/showthread.php?t=677235

The GBAM gearbox is plenty strong to to handle the loads of a very large prop.

Chuck

[Splummer]

Hey Chuck,

Thank you for the post.

It would be great to get some video and details shots of this system, airframe, details, etc. Great to see a NEU really Large Aerobatic electric.

Exciting news on the GBAM, what will the price and delivery time be?

-Sean

[rcelectfly]

Hey Chuck,

Thank you for the post.

It would be great to get some video and details shots of this system, airframe, details, etc. Great to see a NEU really Large Aerobatic electric.Exciting news on the GBAM, what will the price and delivery time be?

-Sean

Sean,

You are welcome. I want to see it fly also.

You will have to ask Steve about that. They are being built to order I believe. It should not take long to get one.

Chuck

[henke]

The NeuMotors GBAM does the same thing for a whole lot less money with one motor and one ESC.


I like Sean as he likes videos, so my guess is still that the Hacker system is the most powerful around for 40% planes.

[Jocke]

So the quad, 4x C50XL, rated to 2,2kw peak 10s, max eff on 1,2kw 88% if i remember correct. Total 8,8-9kw peak?

Any prop data with Volt, Amp, Prop/rpm?

[GWRIGHT]

Most people run the C50's above their 2.2kw rating. The quad systems I've seen run (several of them) are in the 10KW range.



So the quad, 4x C50XL, rated to 2,2kw peak 10s, max eff on 1,2kw 88% if i remember correct. Total 8,8-9kw peak?

Any prop data with Volt, Amp, Prop/rpm?

[GWRIGHT]

I played with gearing outrunners (on small stuff,.. 200 to 400 watts into A30 hackers) and there's definately something to be gained there. I was doing some very low ratios,.. 1.2 to 1.8 due to prop clearance,..but the results were very good. I think it's something worth exploring. I've often thought of even larger stuff. You can find some homebuilt fullscale planes,..like the Rutan Quickie for instance,..that flew on 18 to 22 horsepower (about 15 kilowatts). The A200 will do that, but only with a "little" (comparatively speaking) 32 inch prop. The Quickie, and a couple other homebuilts that size, use 40-ish inch props. The 44X28 being very popular. hmmmm,.. gear an A200 to use a 44X28,.......................... :eek:

Obviously you guys have a lot of knowledge and experience and I cannot contribute here. Please allow me to ask a question.

What is the feeling about geared outrunner? I am planning some big scale models and am more interested in big prop efficiency and thrust than speed. Am I "silly" to want to use a geared outrunner for even bigger props? The planes will have really LOW wing loadings.

[KatManDEW]

Very interesting discussion. I have a 35% plane with the Neu motor, running on 5000+ watts. I see some flying 35% planes with outrunners and10,000+ watts. Seems like a large difference in power to me.

Kilowatts are a terrible thing to waste :)

[GWRIGHT]

It's sort of like whats happened with electric helicopters. Guys could have ample performance for 8 to 10 minute flights, but they set them up for 4 or 5 minutes of insanely ballistic performance, simply because they can.

Very interesting discussion. I have a 35% plane with the Neu motor, running on 5000+ watts. I see some flying 35% planes with outrunners and10,000+ watts. Seems like a large difference in power to me.

Kilowatts are a terrible thing to waste :)

[portablevcb]

I do like this discussion. As a soon to be newbie to giant scale ("only" 1/4 scale :) ) I am interested in geared vs outrunner. I have been partial to geared and belt drives in smaller stuff. But, I have to admit it's mainly because I like the noise they make :rolleyes: On the larger stuff there's enough prop noise to make that a non-issue.

The second consideration was because of prop size. At the time I built those planes outrunners still were limited to smaller props. Now the outrunners are being made that will run with larger props. The simplicity of the outrunner and not having to buy (and maintain) a geardrive is going to move me toward an outrunner for my project. As Sean pointed out at the beginning, the extra weight further forward is a big factor for me too. I really hate adding lead to balance a plane!

Now we need a good discussion of batteries and how long they last at high current draws. I know the motor will last forever (almost). What I hate is to have a battery pack go bad, especially when it will cost more than the motor!

And Gary has a point. We all have a 'sweet spot' for how long we like to fly a routine. Some longer than others. Some like to fly two routines on one charge. Others don't mind letting a power system cool down between flights. I've seen folks with big fans directed at their plane in between flights. Some of the glider guys used to put their NiMh packs in a cooler between flights. So, eveyone has their own idea of a 'perfect' power system.

As for efficiency. When you get to larger stuff it does become more important. But, if I can get a decent flight (<10min) on a "reasonable" battery pack without burning my fingers on the motor :) then I consider the power package adequate.

Keep in mind here I am a scale flier so ultimate performance is not my main goal. I would rather spend less for a power package that is 5% less efficient, but, that still meets my needs.

charlie

[BoneDoc]

I thought about getting the NEU as I was starting my 35% Dalton Extra 260. However, cost became prohibitive for me, and instead I opted for the Hacker A60 18L. I was very pleased with the result, and Sean was even kind enough to update mine to the 2007 model. I like the design and it's definitely innovative.

If you check the video on the thread, you can see that 3600 watts on 19.2 lb AUW frame was definitely adequate for my 3D flying (Xoar 24x10). That was on the OLD motor. The new motor is better and yank the plane around even better (APC 24x12).

[Jocke]

Very interesting discussion. I have a 35% plane with the Neu motor, running on 5000+ watts. I see some flying 35% planes with outrunners and10,000+ watts. Seems like a large difference in power to me.

Kilowatts are a terrible thing to waste :)

Yes there is a big diffrens in power comparing 5kw to 10kw, twice as much in fact ;) 27x12" 3blade spinning 6300rpm gives lotts of pull, but the powersystem i use could go in much bigger/havier airframe, maby in future, time will tell, the Katana i have is a nice performer already on 7kw.

[R/C Dallas]

Need new video to go with that new motor doc! I would love to see a full throttle pull from a hover...that'll put the nay sayers to rest I think! Looking forward to the numbers with the 24x12 as well!

[Jocke]

I played with gearing outrunners (on small stuff,.. 200 to 400 watts into A30 hackers) and there's definately something to be gained there. I was doing some very low ratios,.. 1.2 to 1.8 due to prop clearance,..but the results were very good. I think it's something worth exploring. I've often thought of even larger stuff. You can find some homebuilt fullscale planes,..like the Rutan Quickie for instance,..that flew on 18 to 22 horsepower (about 15 kilowatts). The A200 will do that, but only with a "little" (comparatively speaking) 32 inch prop. The Quickie, and a couple other homebuilts that size, use 40-ish inch props. The 44X28 being very popular. hmmmm,.. gear an A200 to use a 44X28,.......................... :eek:


Cyclon has a few gered outrunner options, also Torcman is working on some bigger things i belive.

I have been told by some electric motor engineers that last few years on the outrunner motors they develop the aim is no longer to spin biggest possible prop as it was before, instead effort has made to find best mix of all and trying to fit motor-plane-prop size as the market/pilots want.

[KatManDEW]

5kw to 10kw, twice as much in fact

That's twice as much electrical consumption only. That doesn't necessisarily translate into twice as much thrust/speed.

[Heather]

I would rather spend less for a power package that is 5% less efficient, but, that still meets my needs.


Don't forget that a 5% difference in efficency translates to a 25% change in power handling.

Little numbers can make a big difference.



Heather

[tIANcI]

Heather you are most correct and from what I hear from people who know you I would know never to argue with you. But the statement is based on cost + need v. cost. I love my AXI and Plattenberg motors but I am moving towards motors from DualSky as it meets my needs at 50% the cost of a performance motor. Yes ... the lesser efficiency is very noticeable, very ...

[Tipover]

I'm wondering how dual inline outrunners like the AXI's fall into this discussion. Are two smaller outrunners mech coupled more efficient than one large outrunner for a given wattage/weight setup? Again I suppose higher costs would be the downside.

Kevin

[tIANcI]

Tipover - that's a good question ... however from a cost point of view it seems cheaper to purchase a co-axial twin than one huge outrunner. Maybe its because the twin units are already being produced in numbers. Down side is you need 2 ESCs. :)

[KatManDEW]

Down side is you need 2 ESCs

I think the ones I've seen also used two sets of batteries? If that's the case, multi motor setups seem impractical to me.

[Tipover]

From a technical standpoint, I'm not sure why you'd need two sets of batteries to power two ESC's and motors, as long as you're not exceeding the batteries total C rating. Even so, many giant electric planes are allready using parallel packs for duration or to obtain C rating. So what would the downside be?

[edit] Come to think of it, why do you need two ESC's? The motors are mech coupled so they could be timed together?

Kevin

[tIANcI]

The motor set up can be twin or quad, we can still use 1 set of batts to power it up. Can 4 ESCs go to 1 channel on the RX? Using 3 Ys?

[Tipover]

The motor set up can be twin or quad, we can still use 1 set of batts to power it up. Can 4 ESCs go to 1 channel on the RX? Using 3 Ys?

I don't see a problem. Worst case the signal may need to be buffered through something like a power box to lower the receivers output impedence. As a side benifit the total wattage of the power system would be distributed over a larger area of heat dissapation.

Kevin

[tIANcI]

Interesting ... maybe one day I will get a B17 up ... :) 4 pieces of AXI 5330? :) Now we are talking Giant Scale!!!

[Tipover]

On a giant scale B17 I think you'd want 4 separate batteries. Or else Use #4 welding cables running out to the ESC's ;)

Kevin

[tIANcI]

Kevin - farnee ... yeah I need the DCA clearance too, the plane should have a 200" wingspan and weight about 125 lbs. :)

[dalbert02]

I am a newbie to giant scale. However, to fuel the in-out debate, I remember reading something about efficiency and how important it is especially for larger aircraft. Suppose you have a outrunner running at 10kW that is 85% effecient. That means 15% waste heat or 1500 watts wasted as heat. I think my heat gun is rated at 1500 watts... Anyways, now suppose you have an inrunner that with gearbox losses is 90% effecient. Would that not mean that 500 watts are no longer wasted? To me, that seems rather significant. 33% less wast heat. Imagine when we get up to 20 and 30kW systems. I would think that these small percentages become even more important. Well, these are just my opinions, maybe flawed, but perhaps something to consider.
-dave
PS looks like the full scale sonex at oshkosh is an inrunner.

[Tipover]

1500 watts seems like a lot of energy to waste, but relative to what most other large power systems waste its not that bad. Consider what’s been going on with big gas engines over the last several years. As long as we have the power to weight, good flight duration, reliable operation, and all at a relatively comparable cost to IC, I think around 90% of the potential users will be happy. I think the large outrunner has already become the practical EP system of choice. Look at the motor selection that's become available in just the last couple years. The other 10% will still always want the best, and they're willing to pay the extra dollars to get it. :)

Kevin

[SD_Raptor]

I see cost mentioned several times in this thread. Outrunners appear to cost less. However, this is the short term initial cost, ignoring a couple of other factors. If a more efficient motor is used, two cost reductions are obtained.

1. A lower current rating ESC may be used. So you may save $30-$70 using a lower amp rated ESC.

2. Lower A-Hr batteries can be used and still have the same flight duration. dropping from 12S 5000 to 12S 4600 saves $120-$180 for two sets of pack. This savings is realized every time you replace batteries.

When you are investing a few thousand on an airplane, putting expensive digital servos, exotic power distribution, often dual receivers (usually PCM as well), upgrading to CF spars and landing gear, etc., does it really make economic sense not to use a power system that is on a par with the rest of the gear?

So, using a 15% more efficient motor saves $150-$250 for the initial outlay, which nearly offsets the extra cost of using an inrunner vs an outrunner. Replace the batteries once, and the inrunner is ahead in cost. And the batteries on the more efficient system will generally be pulling less current, which should extend the life of the batteries, making replacement less frequent, adding to the long-term savings.

I have switched two planes from outrunners to inrunners, and probably will never go back. The flight performance of the inrunners is equal to or better than the outrunners they replaced. I reduced the weight of both planes, not only with the slighter weight of the motor but by being able to use a lighter motor mount as well, and by having the ability to use slightly lower capacity batteries. I have something over 300 IMAC pattern flights over the last six months (yeah, I practice a lot) on the Neu 1515/3D that is in my 74 inch Yak. The gearbox sounds as good as it did on the first day.

Note: I am completely independent in my opinions and receive no sponsorship from any manufacturer (darn it all). I am writing based only on my own experiences.

I also recently upgraded to a JR 9303 - wish I had done that when I upgraded to the Neu motors. Both investments are well worth the money.

One other fun feature of flying with the single gearbox inrunners - people who have never seen them are amazed that such a small motor can fly such a big plane :D

[Jocke]

To make a high performance high efficient (86-90%+) outrunner costs more than the equal inrunner for serial production i have been told, 4-6% higher max efficiency on the outrunner tends to cost up to 30% more to the final pricing of the outrunner. A simple outrunner is basic yes, but if one wants equal or better efficiency and same or better power to weight as the oposit inrunner it will cost, often more in the end.

The way i look at it, a more relieble setup then a direct drive motor using one controller and a high voltage pack is hard to beat, there is a reson why big sucsessfull and experienced manufactors/engineers go for the direct drive shoice, as it is now the best design is the outrunner. Exept Neu motors i do not know of any manufactor (european or asian) who isent working hard in reserch and development of big setups for planes that isent direct drive/outrunner concept.

[Tipover]

I know a few giant IC plane fliers that would never consider converting to giant EP simply because the cost of a really bad crash seems much higher to them. They say that comparably speaking we’re carrying several years’ supply of fuel on board the plane. So they look at it more from a liability/security point of view. Somehow this concept factors into this inrunner vs outrunner discussion. Although if an outrunner and geared inrunner can be made equally efficient for the same $$ I guess its a wash ;)

Kevin

[Thomas B]

For sport giant scale, it is hard to beat the simplicity of large outrunners........and the lack of gear box upkeep....:)

Hardcore giant scale aerobatics seems to favor the geared inrunner.

There is no single solution.

[rcelectfly]

SD_Raptor did not mention one other cost factor involved with the outrunners he had in one of his planes. One outrunner shorted and caused the ESC to go up in smoke and flames. It almost cost him the plane but he was able to get it on the ground and extinguish the flames. Losing a motor and ESC is way more expensive than paying for the little bit extra that a good inrunner and gearbox would cost.

By the way the Motor and ESC were being used within specs and were the manufacturers recommended setup for the plane.

His inrunner motors have been trouble free.

Chuck

[SD_Raptor]

For sport giant scale, it is hard to beat the simplicity of large outrunners........and the lack of gear box upkeep....:)

Hardcore giant scale aerobatics seems to favor the geared inrunner.

There is no single solution.

Apparently you did not read my previous psot carefully - I have at least 300 hard flying aerobatic flights on my Neu 1515/3D with zero maintenance! The motor and gearbox are actually a bit more quiet than when new - the gears have finally burnished well. My other Neu inrunner has only 150 or so flights - also with zero maintenance. One day when the weather is too bad to fly, I'll pull the cowling and service the motors. At the same time, I'll clean the heatsink on the ESC (another necessary and oft overlooked routine mainteance requirement), pull the connectors apart and inspect for wear, arcing, corrosion, and do the other routine chores like check for servo backlash, etc. Gear maintenance is required no more frequently than the other tasks.

While it is true that the old, open frame inrunner gearboxes and some of the earlier versions of sealed gearboxes required maintenance every 50-100 flights (maintenance that takes all of 30 minutes or less), the new gearboxes are nearly maintenance free.

In my opinion, geared inrunners will have a longer life overall. The open frames of outrunners allow dirt to easily get into the motor as air flows freely through the motor. My Neu motors are nearly sealed since the airflow is all around the casing, not through the guts of the motor. At dirt fields or fields with dirt aprons a lot of grit gets into the motor. This will eventually take its toll on an outrunner, with much less effect on an inrunner.

Jocke, perhaps the reason no manufacturer other than Neu is developing high power inrunners is that they believe that Neu is so far ahead that they no the race is lost to them. So they choose the easier and less efficent path. When they were developing geared inrunners, they gave us the designs that gave inrunners and gearboxes a reputation for high maintenance and very high cost. Neu found a way to beat the maintenace issue, and keep the cost of a high efficiency geared motor realistic - no 4-motor/4-ESC/ultrahigh maintenance gearboxes.

Randy

Again, I reiterate that I am in no way sponsored by any manufacturuer. I pay for all of my gear. after flying ourunnerss and Neu geared inrunners, and speaking to many of the pilots of large electric planes, I have no doubt that at least the Neu geared inrunners are superior to their outrunner cousins, in every way but initial cost. After a year or so, the overall cost advantage is also a moot point.

Just to present a complete picture, Neu motors also manufactures outrunner motors (some of them quite large) and recommends them when that is the appropriate motor for the application.

================================================== =====

[tIANcI]

Neu motors ... little things that are happy spinning at 60,000 RPM. :) You guys are lucky ... over here its a little hard to even get gearboxes for speed 400s, as in having gearboxes readilty available in most LHS.

[Thomas B]

Apparently you did not read my previous psot carefully - I have at least 300 hard flying aerobatic flights on my Neu 1515/3D with zero maintenance!
================================================== =====

Actually, I did read it.....I do realize that some of the newer gearboxes are better.

I have seem more than one large Hacker geared inrunner have the gearbox fail in flight and at least one was well under 300 flights.....so there is more than one side to the story.

Remember..I said large outrunners were good for sport use...I was not including hard aerobatics as sport use and indeed said that geared inrunners were a good idea for heavy large scale aerobatic use.

[SD_Raptor]

Neu motors ... little things that are happy spinning at 60,000 RPM. :) You guys are lucky ... over here its a little hard to even get gearboxes for speed 400s, as in having gearboxes readilty available in most LHS.

Oddly, it is not that different over here. Cheap, brushless outrunners have taken over the electric motor market by and large. Brushed motors can still be found - one LHS has a good selection of the hgiher end brushed motors. It is getting harder to find the higherr quality outrunners like the Hackers as the cheap Chinese 'copies' flood the market. But this does allow new comers to enter the hobby and have far better performance than they typially could have achieved just a few years ago.

[pmackenzie]

Just to present a complete picture, Neu motors also manufactures outrunner motors (some of them quite large) and recommends them when that is the appropriate motor for the application.


Do you have a link? I have never seen a Neu outrunner.
Are you thinking of the ORK? Or some sort of non-R/C motor?

Pat MacKenzie

[tIANcI]

SD - I think the demise in inrunners is because of cheap outrunners. I will be seieng a nice Nue soon, friend just got it for his pylon plane some Jibe etc. :) It will turn a 5" prop at like 43K RPM! I can't wait to see it scream.

[SD_Raptor]

Do you have a link? I have never seen a Neu outrunner.
Are you thinking of the ORK? Or some sort of non-R/C motor?

Pat MacKenzie

You may be right and I confused the ORKs with outrunners. I'll have to ask Steve Neu at the San Diego IMAC competition tomorrow. Yes he flies - F5B primarily but also a good IMAC pattern flier.

Randy

[SD_Raptor]

SD - I think the demise in inrunners is because of cheap outrunners. I will be seieng a nice Nue soon, friend just got it for his pylon plane some Jibe etc. :) It will turn a 5" prop at like 43K RPM! I can't wait to see it scream.

Take some earplugs - those high rpm screamers are obnoxious!

Saw the new Neu fan cooled heli motor today - was just barely warm after ten minutes of flying. Bird had about 30 inch (75 cm) rotor span, flying on 6S

================================================== =====

[tIANcI]

SD - okay ... a pair of ear plugs will be ordered. I am going to get a Comp ARF 2 x 2 Extra up and I am most keen on using the branded stuff. My DualSky outrunner is nice and cheap but down by 20A on something like an AXI. Maybe I will get a Neu inrunner with a gearbox. Bite the bullet and get something good for once. :)

[SD_Raptor]

After burning up a large outrunner in my 74 inch Yak, I tried a DualSky because the LHS had one. Before I installed it in the plane, I ran it as a generator to look at the matching of the phases - it was horrible compared to other motors that I had tested. When I finally purchased a Neu motor, it was much better than any other motor I have tested. Most outrunner motors match to roughly 1%. The Neu matches to within 0.2% - this implies that it has very tight tolerances on virtually every component.

If you get a Neu, you will not be disappointed!

[cj-bipe]

Hi Guys,just Thought I'd Way In.my 46% Ultimate Has The Gbam In It.first Let Me Say That I Have Played With Multle Motor Set-ups And Such But Nothing Compares To This.the Gear Box Steve Has Made Is Like One In A Truck Not Your Tipical Rc Application,but Also Light.the Biggest Thing That I Can Say About This Motor And The Big Outrunner's Is The Amp Draw.the Big Outrunner's Run On Low Voltage An Draw Temenous Amps.the System I Have Is High Voltage Low Amps,which Imho Will Save Your Batteries In The Long Run Along With Everything Elese.the Hottest I Have Ever Got This Combo Even With My New Prop Has Been,motor,133deg.,speed Controller 86deg.,batteries 95deg.let Me Add This Thing Has Ton's Of Power.i Apologize That There Hasn't Been Any Vidie Posted Yet About This Set-up But My Son Has Been Very Ill And Has Taken Alot Of Our Time.i Will Get Some Vid. Soon.great Disscussion But I Feel This Is The Way To Go Imho.



Regards,cj

[Tipover]

the Biggest Thing That I Can Say About This Motor And The Big Outrunner's Is The Amp Draw.the Big Outrunner's Run On Low Voltage An Draw Temenous Amps.the System I Have Is High Voltage Low Amps,which Imho Will Save Your Batteries In The Long Run Along With Everything Elese

I could be wrong, but I don't think all big outrunners are designed to run on low voltage and high amps. I think that is more a function of the motors number of windings and KV rating. :confused: To many watts is what kills electrical and electronic stuff.

Kevin

[KatManDEW]

To many watts is what kills electrical and electronic stuff.

Amps are what kill, electrical components and humans. That's why power distribution is high voltage. High current requires large conductors, and conductor sizes can get ignorant as current demands get large, especially with DC power. High voltage requires only good insulation. We're pushing the limits of conductor sizes already in model aircraft.

Look at Tesla's experiments with extremely high voltage and extremely small current.

Sensible power (watts) combines a balance of current and voltage. Right now we're running way more current than voltage.

10kW at 50 volts requires 200 amps. And 200 amps is extreme now matter how you cut it.

10kW at 100 volts is 100 amps. And is much more sensible.

If we were running low voltage in our houses (say 50 volts), we would need much bigger wiring. And we're running AC in our houses, which is much better for power distribution. DC power has massive losses across conductors. Try running an extension cord from you car battery to your battery chargers, and see how badly the voltage drops. Your chargers will be beeping because of low voltage input. Run the same extension cord with 110vac to a DC power supply to power your chargers, and the same extension cord is now sufficient.

We need higher voltage to drop current to sane levels.

[pmackenzie]

Careful analysis of power system components will show you that is not the case.

Battery:
50 volts at 200 amps vs 100 volts at 100 amps.
Assuming the battery weight is fixed the pack could be made out of the same number of cells, just arranged differently.
For example 13S4P 20 Ahr versus 26S2P 10 Ahr
Each cell in the packs will see the same current in both configurations., 50 amps
Nothing to be gained here.

Motor:
Assuming gearing and prop is the same the higher voltage will require a lower KV. This means more turns of thinner wire.
Thinner wire = higher resistance. It will all come out the same in the end. Look at the tables for Neu motors.
Each motor frame has the same power limits regardless of wind. Ditto for efficiency.

Speed controller:

The higher the voltage the FETs are, the higher the resistance is. This comes down to the physics of how the semiconductors work.
This is in part why HV controllers are larger than LV ones. They use more and larger FETS.
High voltage FETs are also more expensive than the more common low voltage ones.

Wires and connectors:
Here the HV setup wins, but losses in the wiring of a model are probably the smallest in the whole system.
Total wire length is at most a couple of feet.

What can make a difference is incremental changes.
Going from say 12S to 14S without requiring a change in the speed control or battery capacity can let you run a smaller prop at lower current for the same power.

Pat MacKenzie

[KatManDEW]

I still think we need higher voltage, and less current than what we're running on big stuff.

[Tipover]

As far as humans are concerned, as little as 50 joules has been know to take some out. This has to do with conduction paths and efficiency of conduction. Same efficiency deal going on with high voltage transmission lines. Personally, speaking from experience, I'd rather grab ahold of 50v over 100v any day ;)

Kevin

[tIANcI]

SD - you get what you pay for ... I will let you know how happy I will be, and I am sure I shall be, when I purchase a nice Neu! Can you advice me what to get if I wanted to fly my 80" 13 lbs plane? I will go with a 10S set up and prob a 22x10 prop to start with.

Tipover - I grabbed hold of 220V before ... it was most interesting. I did not feel myself landing on the floor! Back then break dancing was in and it was at a party so you can imagine ...

[rcelectfly]

You may be right and I confused the ORKs with outrunners. I'll have to ask Steve Neu at the San Diego IMAC competition tomorrow. Yes he flies - F5B primarily but also a good IMAC pattern flier.

Randy

Randy,

The ORKs (Out Runner Killers) are inrunners. NeuMotors does not currently make any out runners.

Chuck

[pmackenzie]

Tipover - I grabbed hold of 220V before ... it was most interesting. I did not feel myself landing on the floor! Back then break dancing was in and it was at a party so you can imagine ...

I got a 575V 3 phase shock once, from one phase to another.
I won't go into details, but it was a total brain fade moment. Really stupid.

Fortunately it was entirely my hand that got the shock, finger to thumb.
Feels very different than a 110v "tingle"

Pat MacKenzie

[tIANcI]

Pat - thank your lucky starts for circuit breakers and rubber shoes? :)

[pmackenzie]

Breaker never blew.
I was wearing running shoes.

Pat MacKenzie

[Tipover]

I got a 575V 3 phase shock once, from one phase to another.

Feels very different than a 110v "tingle"

Pat MacKenzie

Somewhat like a body slam into a cement wall?

I've gotten a few 400-600dc shocks while working on vacuum tube power supplies. Even with the mains power off the filter capacitors can give you a real wollop. It just dang hurts.

Kevin

[SD_Raptor]

Amps are what kill, electrical components and humans.



Electrical components are not killed only by amps.

1. MOS and many other semiconductor devices are very sensitive to voltage which can short out the thin dielectric insulating layer. Below a certin threshold voltage, the devices have no problems. That is why many packages have static sensitive labels.

2. Heat is the enemy of most other semiconductors. If you want to prove this, disbale the fan on the CPU in your computer - the voltage and current don't change much but the heat buildup will fry its little brain.

3. For motors the situation is far more complex. Heat buildup is limited by the thermal properties of the insulation on the magnet wire. High temperature insulation is great but expensive for fabrication since each winding must be stripped individually. Maximum current is primarily determined by how efficiently the heat can be removed from the motor. Maximum voltage is determined by the breakdown voltage of the insulation. Thicker insualtion would be nice but reduces the winding density - winding density is very important for efficiency. As the magnetic field intensity increases (determined by current and winding density) the magnetic pressures come into play, requiring great care in winding, stator design, and materials strength. To complicate matters further the induced eddy current losses most also be considered.

There is no simple solution. Each application has a range of motors that will work, covering some range of voltage. The choice is the users. Fortunately these days, we have a wider range of solutions than ever. depending on the plane, your preference of fly style, niche within that style, budget, etc., you get to choose the voltage, current, KV, size, weight, prop size or efficiency that best meets your needs.

What you do find in the industrial motor market is that as power requirement increases, motor voltage increases faster than motor current for high rpm motors and current is usually higher for lower rpm motors (high and low are relative terms, to put it mildly). In this market a huge range of gearboxes are available to best match a motor to its application. Often the gearbox costs as much or more than the motor.

Randy

[BoneDoc]

All this brings back to the same point:

It's nice to have a geared inrunner if you've got the dough, but for a lot of us, outrunners are simpler and cheaper :).

[feathermerchant]

Well said. That is a simple solution.

[Jocke]

I could be wrong, but I don't think all big outrunners are designed to run on low voltage and high amps. I think that is more a function of the motors number of windings and KV rating. :confused: To many watts is what kills electrical and electronic stuff.

Kevin

The fact that outrunners are designed for 12-15s Lipo is bcas of rules and laws of in the european union.... if a eropean manufactor makes a motor designed for more than 15s Lipo there will be no market at all, over 14s Lipo, it gets very dangerous.

[Jocke]

Apparently you did not read my previous psot carefully - I have at least 300 hard flying aerobatic flights on my Neu 1515/3D with zero maintenance! The motor and gearbox are actually a bit more quiet than when new - the gears have finally burnished well. My other Neu inrunner has only 150 or so flights - also with zero maintenance. One day when the weather is too bad to fly, I'll pull the cowling and service the motors. At the same time, I'll clean the heatsink on the ESC (another necessary and oft overlooked routine mainteance requirement), pull the connectors apart and inspect for wear, arcing, corrosion, and do the other routine chores like check for servo backlash, etc. Gear maintenance is required no more frequently than the other tasks.

While it is true that the old, open frame inrunner gearboxes and some of the earlier versions of sealed gearboxes required maintenance every 50-100 flights (maintenance that takes all of 30 minutes or less), the new gearboxes are nearly maintenance free.

In my opinion, geared inrunners will have a longer life overall. The open frames of outrunners allow dirt to easily get into the motor as air flows freely through the motor. My Neu motors are nearly sealed since the airflow is all around the casing, not through the guts of the motor. At dirt fields or fields with dirt aprons a lot of grit gets into the motor. This will eventually take its toll on an outrunner, with much less effect on an inrunner.

Jocke, perhaps the reason no manufacturer other than Neu is developing high power inrunners is that they believe that Neu is so far ahead that they no the race is lost to them. So they choose the easier and less efficent path. When they were developing geared inrunners, they gave us the designs that gave inrunners and gearboxes a reputation for high maintenance and very high cost. Neu found a way to beat the maintenace issue, and keep the cost of a high efficiency geared motor realistic - no 4-motor/4-ESC/ultrahigh maintenance gearboxes.

Randy

Again, I reiterate that I am in no way sponsored by any manufacturuer. I pay for all of my gear. after flying ourunnerss and Neu geared inrunners, and speaking to many of the pilots of large electric planes, I have no doubt that at least the Neu geared inrunners are superior to their outrunner cousins, in every way but initial cost. After a year or so, the overall cost advantage is also a moot point.

Just to present a complete picture, Neu motors also manufactures outrunner motors (some of them quite large) and recommends them when that is the appropriate motor for the application.

================================================== =====


So how many worls champ F3A, or F5B competitions have the "worlds greatest motors-Neu" winns have, i belive when it comes to winning these things its hard to beat Hacker and Plettenberg, they are now making outrunners, also Kontronik ;) i belive they do not think Neu is to far ahead... they still make winning inrunners AND orutrunners, for diffrent aplications.

Sorry but there is no rule in our world that says and inrunner is more efficient than the outrunner design, i have been in contact with many enginners in europe and asia working for big manufactors, non of them say one design is more efficient or has more power to weight than the other.... they know what they are talking about (exept for the Ezone ;)

[SD_Raptor]

So how many worls champ F3A, or F5B competitions have the "worlds greatest motors-Neu" winns have, i belive when it comes to winning these things its hard to beat Hacker and Plettenberg, they are now making outrunners, also Kontronik ;) i belive they do not think Neu is to far ahead... they still make winning inrunners AND orutrunners, for diffrent aplications.

Sorry but there is no rule in our world that says and inrunner is more efficient than the outrunner design, i have been in contact with many enginners in europe and asia working for big manufactors, non of them say one design is more efficient or has more power to weight than the other.... they know what they are talking about (exept for the Ezone ;)

Jocke,

The manufacturers for whom you work, either directly or indirectly as a sponsored flier, are not going to tell you the whole truth, particularly if they know the truth will be detrimental to their business. Whether you want to believe this, it is nonetheless entirely true.

Simply look at the specs and measured performance of the motors. The majority of inrunners are more efficient than all but the most expensive outrunners. Likewsie for power to weight - inrunners almost invariably have the advantage. Not all, since there are poorly designed and manufactured inrunners.

From a purely mechanical viewpoint, inrunners have several advantages:

1. The spinning mass has a low monent of inertia. This obtains faster acceleration and deceleration. Having the mass closer to the shaft means that any error in mass distribution causes less force on the bearings and less vibration of the entire plane.

2. Because the angular moment is smaller, the change is magnet gap will change less in response to centripital force or to temperature changes for an inrunner than for an outrunner of equal power output. This is one reason that inrunners maintain their high efficiency to the top end of the power band.

3. Inrunner magnets can be more securely fastened to the rotor since the they can be wrapped in high tensile strength materials.

4. The majority of outrunners acheive maximum efficiency at around 50% maximum power while the inrunners have higher and flatter efficiency throughout the higher portion of their power band.

I cannot recall ever having heard of in inrunner throwing a magnet. I have witnessed or read about amny outrunners throwing a magnet. The primary reason that outrunners throw magnets is that the magnet bell is made of a material, which compared to the material of the magnets, has very different thermal, magnetic, and mechanical properties. And since maintaining a small magnetic gap is crucial to good motor power and efficiency, the magnets cannot be restrained by clamps, but are held in by adhesives. These adhesives have physical properties very different from the material of the magnets or the bell - this almost guarantees an eventual bonding failure after enough thermal or mechanical load cycles, particularly for the higher powered motors which have much higher mechanical and thermal loading than the smaller motors.

By way of background, I am an industrial physicist. I enjoy dissecting technology to see how it ticks and dtermining the subleties of whyone technology outperforms another. After much study of many motors, I have no doubt that inrunners are superior to outrunners, particulalry at the higher power levels and that when the difference in cost of the motors is compared to the total cost of the plane, inrunners are only a few percent more expensive than outrunners - if you also factor in the cost of the higher currnet ESC required by the outrunner, higher capacity batteries required by the outrunner, and replacement cost of those large batteries. After one replacement cycle, there is no overall cost in difference. The difference in initial capital cost is 5%, or less, of the total cost of the entire airplane when cost of the appurtances like batteries and speed controls is also factored into the calculation. When the failure rate of outrunners vs inrunners is also factored in and amortized over all electric powered large scale planes, inrunners suddenly become the obvious choice.

Furthermore in many threads about electric powered planes, the reports failures of speed controls operating large outrunners is widespread. I have not read single report of a speed control having problems operating an inrunner. Since the crash of a large scale plane can cost thousands to remedy, I also view the marginally higher cost of Neu motor as cheap insurance against power system failures.

Again, I reitierate, I am in no way sponsored by any company. My analysis and conclusions are completely independent. If there was any outrunner that matched the performance of the Neu motors in my airplanes, I would happily switch over.

Remember that Neu motors is now in business only 5 years. After the 2007 F5B world championships, lets talk again about whether Neu has any winning designs. The situation is changing rapidly. Already in the U.S. they dominate in F5B, are aften the winners in AMA pattern contests even when competing against gas or glow engines, and are the motor of choice for many fliers of electric helicopters. Not bad for a young company.

Well back to flying.

Randy

[KatManDEW]

The fact that outrunners are designed for 12-15s Lipo is bcas of rules and laws of in the european union

Exactly. I believe that is much of the reason we are running high amps and relatively low voltage. European technology represents a large part of development for our part of the hobby, and they must consider their market base.

Is higher voltage dangerous? Say around 100 volts? Sure. But there are 110VAC appliances all over the place outdoors. From light bulbs and power tools, to you name it.

[Surly_Schmidt]

Jocke,

The manufacturers for whom you work, either directly or indirectly as a sponsored flier, are not going to tell you the whole truth, particularly if they know the truth will be detrimental to their business. Whether you want to believe this, it is nonetheless entirely true.

Simply look at the specs and measured performance of the motors. The majority of inrunners are more efficient than all but the most expensive outrunners. Likewsie for power to weight - inrunners almost invariably have the advantage. Not all, since there are poorly designed and manufactured inrunners.

From a purely mechanical viewpoint, inrunners have several advantages:

1. The spinning mass has a low monent of inertia. This obtains faster acceleration and deceleration. Having the mass closer to the shaft means that any error in mass distribution causes less force on the bearings and less vibration of the entire plane.

2. Because the angular moment is smaller, the change is magnet gap will change less in response to centripital force or to temperature changes for an inrunner than for an outrunner of equal power output. This is one reason that inrunners maintain their high efficiency to the top end of the power band.

3. Inrunner magnets can be more securely fastened to the rotor since the they can be wrapped in high tensile strength materials.

4. The majority of outrunners acheive maximum efficiency at around 50% maximum power while the inrunners have higher and flatter efficiency throughout the higher portion of their power band.

I cannot recall ever having heard of in inrunner throwing a magnet. I have witnessed or read about amny outrunners throwing a magnet. The primary reason that outrunners throw magnets is that the magnet bell is made of a material, which compared to the material of the magnets, has very different thermal, magnetic, and mechanical properties. And since maintaining a small magnetic gap is crucial to good motor power and efficiency, the magnets cannot be restrained by clamps, but are held in by adhesives. These adhesives have physical properties very different from the material of the magnets or the bell - this almost guarantees an eventual bonding failure after enough thermal or mechanical load cycles, particularly for the higher powered motors which have much higher mechanical and thermal loading than the smaller motors.

By way of background, I am an industrial physicist. I enjoy dissecting technology to see how it ticks and dtermining the subleties of whyone technology outperforms another. After much study of many motors, I have no doubt that inrunners are superior to outrunners, particulalry at the higher power levels and that when the difference in cost of the motors is compared to the total cost of the plane, inrunners are only a few percent more expensive than outrunners - if you also factor in the cost of the higher currnet ESC required by the outrunner, higher capacity batteries required by the outrunner, and replacement cost of those large batteries. After one replacement cycle, there is no overall cost in difference. The difference in initial capital cost is 5%, or less, of the total cost of the entire airplane when cost of the appurtances like batteries and speed controls is also factored into the calculation. When the failure rate of outrunners vs inrunners is also factored in and amortized over all electric powered large scale planes, inrunners suddenly become the obvious choice.

Furthermore in many threads about electric powered planes, the reports failures of speed controls operating large outrunners is widespread. I have not read single report of a speed control having problems operating an inrunner. Since the crash of a large scale plane can cost thousands to remedy, I also view the marginally higher cost of Neu motor as cheap insurance against power system failures.

Again, I reitierate, I am in no way sponsored by any company. My analysis and conclusions are completely independent. If there was any outrunner that matched the performance of the Neu motors in my airplanes, I would happily switch over.

Remember that Neu motors is now in business only 5 years. After the 2007 F5B world championships, lets talk again about whether Neu has any winning designs. The situation is changing rapidly. Already in the U.S. they dominate in F5B, are aften the winners in AMA pattern contests even when competing against gas or glow engines, and are the motor of choice for many fliers of electric helicopters. Not bad for a young company.

Well back to flying.

Randy


Just what two motors you comparing?

For a 3000w system it looks to me like you will have 25-28oz of metal up front regardless of configuration.

Yet the cost of a neu(1521+box) is double the price compared to a hacker A60-18L.

Actual power? Both manufacturers consider this information highly confidential.

[KatManDEW]

Actual power? Both manufacturers consider this information highly confidential.

There's another factor - how much energy consumption is necessary to deliver that in-flight power? ie: the elusive efficiency factor.

One of these days there will be enough of both types of motors in use, that comparisons of in-flight power, and energy consumption, will be well known. As it is now, I've heard no first hand reports of both side by side.

My only first hand comparison to date is with two ~1000 watt outrunners, on the same planes which once had geared setups on them. The result is that the outrunners generate the same in-flight power, but they require almost 30% more input power to do so. Reports I see online for larger setups, and motor calculators, seem to show the same trend.

30% isn't a big deal to waste on a foamy where it's easy to supply more than sufficcient batteries, but 30% of several kW is a considerable amount when we're already pushing big battery packs to their limits.