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Old Jul 24, 2010, 02:58 PM
Foaming at the mouth..
darksiede's Avatar
USA, KS, Topeka
Joined Jul 2008
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Taking the UM's brushless.... staying 1s

Ok, I've been researching and I have most of the parts on-hand or on the way to me currently, and plan on experimenting and posting my results in full.
What I am looking for is a good to excellent alternative to the coreless pager motors most of us currently fly in our 1s UM planes. An alternative that does not entail going to 2s..

We can go with a 12mm inrunner, using a 3.5:1 gearbox.:

cheap walkera 12mm 11000kv inrunner $16.50 (on another site)
This particular one is 10g, but they can be found as low as 8 grams..

cheap BP 3.5:1 gearbox for 12mm innrunner $7.95
This part weighs in at 13.4 grams

Obviously we need a 1s capable esc for this setup:
1s 10a brushless esc with faster switching for inrunner costing $12.50
The esc weighs in at 6 grams

Going to a larger motor that will need more amps then stock 150mah cells can kick out, we would need to go bigger here as well..
280mah 25c 1s from Common sense RC, costs $18.95 for a twin pack
The cells weigh in at 8 grams each..

Simple math tells us we are adding 37.4 grams of weight to the plane.. We are going to loose some weight before these parts go in however..
I'm not sure how much we gain back from loosing the stock motor & gearbox, as well as how much more the 8g lipo weighs over a stock 150mah lipo..

I am guessing to say we are going to add at least 25g total weight after parts exchange to most planes.
That would give us an estimated AUW of around 50 grams / 1.76 ounces, including the battery.

Running the math through Ecalc I can produce some very interesting results:

At WOT the entire flight a pack would hit LVC at 6.5 minutes, mixed flying could give 10+ minute flights..

1s1p 280mah pack at 4.2v (fresh charge), 10 amp esc, and a 5043 prop:
3.92 ounces! / 111.2 grams! of thrust
Pitchspeed of 36mph at 3.6 amps..

1s1p 280mah pack, at 3.7v (LVC), 10 amp esc, and a 5043 prop:
3.17 ounces / 89.8 grams of thrust
Pitchspeed of 33mph at 3.0 amps..

On a fresh pack we would have a 2.22:1 thrust to weight ratio and even at the end of the pack, we are maintaining a 1.81:1 thrust to weight ratio.
More then enough to prop hang the entire flight...

On a plane like a Champ, I can see this being awesome.. Able to carry more payload with only a slight affect from the added wing loading.
I know I have flown mine with 25 grams extra weight on it and was still cruising below 50% throttle on a stock plane.

I can't really comment about the mustang as I don't own one..

However the question would be what about the Sukhoi? (and 4site which I don't own fits here as well)
Higher wing loading on those is averse to what they are made for, but where is the fine line?
I haven't really modded my Sukhoi's beyond taping a 280mah pack to the belly, and I did notice the weight in sport flying.
I also noticed the extra authority it gave me in dealing with the wind however.

So I guess the question comes down to this... at a total cost under $60... would you?

Ideas, thoughts etc etc.. please.. I've spent several hours digging around and hunting things down to research this completely out, hunting for the lightest & best options..
I know some weight and possibly cost could be saved going for a 5a esc from say HC.. I am however going with what I have on hand already...


~Kev
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Old Jul 25, 2010, 12:18 AM
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USA, OK, Muskogee
Joined Nov 2008
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Well Kev, it would seem that everything is too heavy.
I, for one, can't understand why the market is not already flooded with 2g outrunners.
If you look at the very old and still very interesting thread here: http://www.rcgroups.com/forums/showthread.php?t=596219
Helmut had a vision of nano motors, able to deliver what we want...and more.
My own forays have seen 1.5g thrust brushless, using ex PC CPU fan 4 wire single chip solutions and i'm only a beginner. All scaled, there seems little reasoning why a hobby version of this technique would use brushed motors in 2010.
Price is the lead. A 6mm or 7mm pager costs 'tuppence hapenny' as they say.

The Indoor and Micro section has so many AR6400 mods and Vapor conversions and what have you. But, leading edge brushless homebuilds are very few.
Shagrug had one: http://www.rcgroups.com/forums/showt...shagrug&page=3 flight video in that thread.
His motor weighs 0.42g.
A manufacturer hasn't produced anything...this stuff is 4 years old !

A gearboxed nano outrunner, on a Parkzone type plane is certainly where we are at. But, coreless pagers are nearly free and, they really are very efficient.

My vision is of a 2g weight, 10g thrust DD outrunner. Needing a 130mAh 1S lipo power source or less.
Where is it ?
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Old Jul 25, 2010, 12:57 AM
Foaming at the mouth..
darksiede's Avatar
USA, KS, Topeka
Joined Jul 2008
924 Posts
Quote:
Originally Posted by Slider2732 View Post
Well Kev, it would seem that everything is too heavy.
Yes.. we would need near double the wing area to fly as slow as say the champ does in stock form.. But on a sport/3d plane like the sukhoi, is heavier wing loading a negative? On the 4site it's a given that it is..

Quote:
Originally Posted by Slider2732 View Post
A gearboxed nano outrunner, on a Parkzone type plane is certainly where we are at. But, coreless pagers are nearly free and, they really are very efficient.
Nearly free? true.. efficient? questionable.. reliable? hardly!

Quote:
Originally Posted by Slider2732 View Post
My vision is of a 2g weight, 10g thrust DD outrunner. Needing a 130mAh 1S lipo power source or less.
Where is it ?
Thing is, for a 1/72 scale plane.. weighing in under 15 grams and having maybe a 5-8 inch wingspan. sure! that would be spectacular..
However in the realm of one of the most common micro fliers, being the Parkzone birds, 16+ inch wingspans and near 30g weights sans battery.. Lots of people are looking for an alternative to the coreless pager motor blues..
10 grams of thrust is not going to cut it for these birds..

I honestly think that if I can find some 'magic combo' of parts that will only add say 10g to the AUW, yet still provide a 1.75:1 thrust to weight ratio or higher for the entire flight.. We would have that solution..

I had planned on ordering the 5.1g outrunner from HC today, but as usual it's on backorder.. It's a 10mm can, and could possibly slot into the STOCK sukhoi XP / Mustang gearboxes and give us 1/2 the weight of the first motor I have lined up to test.. Ecalc'ing it on a 4:1 gearbox it could pull 3.22 amps at 4.2v, swinging a 5043 prop at 8600+ rpm and give 3.65 oz / 103.6 grams of thrust.. At the LVC we would still have 2.94 oz / 83.3 grams of thrust and be down to 2.71 amps at 7700rpm..

Using a modified stock gearbox, the only real tradeoff would be 5.1g in the motor + 6 grams on the esc.. and 8 grams on the lipo.. We would be loosing a few grams (whats the weight on the stock XP motor anyone?) from the stock motor, and from trading off the 150mah cell.. so new AUW would be an additional 10 grams +/- to the plane.

That would put us around 40 grams AUW give or take a little bit, and almost dead on a 2:1 thrust ratio right down to the LVC cutoff.. Or exactly what I am looking for!

~Kev

PS: If anyone has a spare 5.1g 1015 11500kv outrunner from HC, I'm highly interested in buying it..
http://www.hobbycity.com/hobbycity/s...idProduct=9824
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Old Jul 25, 2010, 10:38 AM
The building never ends!
Tucson, AZ
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Quote:
Originally Posted by darksiede View Post
Yes.. we would need near double the wing area to fly as slow as say the champ does in stock form.. But on a sport/3d plane like the sukhoi, is heavier wing loading a negative? On the 4site it's a given that it is..
Sport planes don't mind a heavier wing loading. 3D planes . . . eh, not quite so much.

Quote:
Nearly free? true.. efficient? questionable.. reliable? hardly!
Here's the rub. An ultra-micro brushless setup is no more efficient than a brushed ultra-micro setup. You're throwing away nearly 40% of your input power as waste heat.

Quote:
Thing is, for a 1/72 scale plane.. weighing in under 15 grams and having maybe a 5-8 inch wingspan. sure! that would be spectacular..
However in the realm of one of the most common micro fliers, being the Parkzone birds, 16+ inch wingspans and near 30g weights sans battery.. Lots of people are looking for an alternative to the coreless pager motor blues..
10 grams of thrust is not going to cut it for these birds..
A cheap three to five gram outrunner of around 4000 Kv will produce around 40 grams of thrust on less than two amps of current on 1S, if you're using a GWS 4025 or 4530 prop. They'll produce up to sixty or so on a GWS 5030 prop for less than three amps of current. Yes, you'll need to use a 6-7 gram 250 mAH 1S LiPo, and at least a 3A 1 gram ESC, but that kicks a Sukhoi up to 38 grams AUW. A micro outrunner gearbox will do the same thing for less than 2A of current. Of course, the gearbox needs some mods to achieve its potential.

Quote:
I honestly think that if I can find some 'magic combo' of parts that will only add say 10g to the AUW, yet still provide a 1.75:1 thrust to weight ratio or higher for the entire flight.. We would have that solution..
Not going to happen. At least, not on a motor that costs appreciably less than the plane it's going into. 1.75:1 thrust-to-weight on a 45 gram plane (that's a Sukhoi with 10 more grams AUW) is ~79 grams. Only way you're going to get a micro brushless motor to produce that much thrust is by going 2S. A competently-executed 2S setup will add a mere 11 to 12 grams to the AUW and produce over 90 grams of thrust.

Quote:
I had planned on ordering the 5.1g outrunner from HC today, but as usual it's on backorder.. It's a 10mm can, and could possibly slot into the STOCK sukhoi XP / Mustang gearboxes and give us 1/2 the weight of the first motor I have lined up to test.. Ecalc'ing it on a 4:1 gearbox it could pull 3.22 amps at 4.2v, swinging a 5043 prop at 8600+ rpm and give 3.65 oz / 103.6 grams of thrust.. At the LVC we would still have 2.94 oz / 83.3 grams of thrust and be down to 2.71 amps at 7700rpm.
Wow . . . what numbers are you plugging in to get figures like that? I plugged the same motor into the calc program you're using, and it's spitting out 71 grams of thrust at the top of the pack and 56 grams at the bottom of the pack using a GWS 5030 prop. For less than 2A of current. Which is what I'd expect, and what I've seen, from a 1S gearboxed inrunner setup.

Quote:
Using a modified stock gearbox, the only real tradeoff would be 5.1g in the motor + 6 grams on the esc.. and 8 grams on the lipo.. We would be loosing a few grams (whats the weight on the stock XP motor anyone?) from the stock motor, and from trading off the 150mah cell.. so new AUW would be an additional 10 grams +/- to the plane.
The stock motor weighs about as much as the motor you're dropping in. You won't be losing any weight. You'll be adding at least five grams of weight you don't need to add, because the motor you've listed only needs a HC 1 gram 3A ESC (since its maximum current rating is 4A for . . . one second. Which likely makes for a motor whose maximum sustained current is less than three amps.)
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Old Jul 25, 2010, 06:38 PM
Foaming at the mouth..
darksiede's Avatar
USA, KS, Topeka
Joined Jul 2008
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Originally Posted by Ensign Jimmy View Post
Wow . . . what numbers are you plugging in to get figures like that? I plugged the same motor into the calc program you're using, and it's spitting out 71 grams of thrust at the top of the pack and 56 grams at the bottom of the pack using a GWS 5030 prop. For less than 2A of current. Which is what I'd expect, and what I've seen, from a 1S gearboxed inrunner setup.
First off, the 5.1g inrunner is the same weight as the stock coreless..
Secondly, it's an 11,500 KV 10mm diameter inrunner, http://www.hobbycity.com/hobbycity/s...idProduct=9824.
Lastly you'd need to modify the stock gearbox, keep its 4:1 ratio, and mount it + the 0.7g esc into the plane. Slap on a 5043 and let it rip..

I'm only really ball-parking the resistance on the esc..



Even down at 3.7v, it's still producing 3.07oz of thrust according to these figures...

So basically, 5.1g inrunner inside the stock gearbox, plus .7 gram esc, a 5043 prop, and the weight difference from running a 280mah 1s pack (common sense rc has 2 packs for $19) You are only adding a FEW grams.. maybe 3 grams total weight.. and theoretically getting massive performance increases, and reliability..

~Kev
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Old Jul 25, 2010, 07:56 PM
The building never ends!
Tucson, AZ
Joined Oct 2008
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Quote:
Originally Posted by darksiede View Post
First off, the 5.1g inrunner is the same weight as the stock coreless..
Secondly, it's an 11,500 KV 10mm diameter inrunner, http://www.hobbycity.com/hobbycity/s...idProduct=9824.
Lastly you'd need to modify the stock gearbox, keep its 4:1 ratio, and mount it + the 0.7g esc into the plane. Slap on a 5043 and let it rip..

I'm only really ball-parking the resistance on the esc..



Even down at 3.7v, it's still producing 3.07oz of thrust according to these figures...

So basically, 5.1g inrunner inside the stock gearbox, plus .7 gram esc, a 5043 prop, and the weight difference from running a 280mah 1s pack (common sense rc has 2 packs for $19) You are only adding a FEW grams.. maybe 3 grams total weight.. and theoretically getting massive performance increases, and reliability..

~Kev
Look at the Rm figure for the motor again. It should be 0.51 ohms, and I've used the calculator's internal resistance figure for a 20C to 25C LiPo cell. And I used the GWS prop parameters, rather than the APC prop parameters.

Finally, I'm using the non-stalled thrust numbers. I note in your screenshot that the calculator is stating that the prop is likely to stall, so the thrust you're going to get will be more like 47 grams, not 107 grams. Which is in line with the sort of thrust numbers that others have gotten taking the Sukhoi brushless. Plug in a 5x3 prop and see what the calculator spits out. Using the assumptions I've stated, the max thrust you get is 71.5 grams . . . but even assuming 4.2V from the battery is quite generous. Under load, the LiPo will quickly fall off to 3.9 to 3.7 V after the first ten or fifteen seconds of use. At the end of the flight, where the ESC invokes LVC . . . the LiPo is delivering ~3.3 V under load. This is why the calculator uses 3.7V as the voltage for a LiPo . . . so the maximum realistic thrust you're going to get will be on the order of under 58 grams. Which is the sort of thrust numbers people have gotten from the GPS-C03 micro-outrunner gearbox, and the best numbers obtained from direct-drive micro 1S outrunners.
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Old Jul 27, 2010, 09:07 PM
Foaming at the mouth..
darksiede's Avatar
USA, KS, Topeka
Joined Jul 2008
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Quote:
Originally Posted by Ensign Jimmy View Post
Look at the Rm figure for the motor again. It should be 0.51 ohms, and I've used the calculator's internal resistance figure for a 20C to 25C LiPo cell. And I used the GWS prop parameters, rather than the APC prop parameters.
Fair enough, here is the correct RM figure, and a GWS prop..



Quote:
Originally Posted by Ensign Jimmy View Post
Finally, I'm using the non-stalled thrust numbers. I note in your screenshot that the calculator is stating that the prop is likely to stall, so the thrust you're going to get will be more like 47 grams, not 107 grams.
At a 4:1 ratio I found the optimal props without stall to be in the 5030 to 6030 range.. anymore pitch and it will stall..

Also, regarding the max amp's on this motor, it is a typo to state 4 amp / 1 sec.. it should read 4 amp / 10 seconds..

Ecalc just updated their pages apparently, and I'm guessing it to be a 2 pole motor..

And finally, this is at the default 3.7 volt reading.. not inflating my numbers anymore with a "fresh" pack at 4.2v

~Kev

Edit: After playing with ecalc more this evening.. a 6038 seems to work well, more thrust & pitchspeed.. also the pole count on the motor is currently not affecting any data.
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Old Jul 29, 2010, 02:50 PM
Foaming at the mouth..
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USA, KS, Topeka
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Yay photobucket is down now and none of my stuff is showing up in here..

~Kev
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Old Jul 30, 2010, 11:19 PM
Foaming at the mouth..
darksiede's Avatar
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Joined Jul 2008
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Images are back.. Still waiting on HC to get the 1015 back in stock and will order a few for testing this completely through for real world results.

~Kev
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Old Aug 05, 2010, 11:01 PM
Foaming at the mouth..
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USA, KS, Topeka
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I received my ChineseJade order today..

That gives me the first test motor, 12mm inrunner of 11,000kv.. I was surprised to find the stock heli brass pinion on it is the correct pitch to mate with stock PZ sukhoi gearboxes. It's quiet the nice bonus, and after this motor does my 1s speed competition entry it will be devoted to the cause of finding a reliable 1s brushless system with good output.

Still waiting on 2 more 12mm inrunners from 2 different sites to come in, and waiting on HC to restock the 10mm inrunner for testing purposes as well..

~Kev
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Old Aug 06, 2010, 12:42 AM
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I await your results. I would love to see a reliable 1s UM powerplant.
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Old Aug 06, 2010, 06:51 AM
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What length are those 12mm inrunners, Kev? The shortest I have seen is the baby Feigao at 22mm.

Tony
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Old Aug 06, 2010, 04:00 PM
Foaming at the mouth..
darksiede's Avatar
USA, KS, Topeka
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Originally Posted by t-turley View Post
What length are those 12mm inrunners, Kev? The shortest I have seen is the baby Feigao at 22mm.

Tony
The Walkera I received yesterday is 18mm case length, 20mm overall (Case+shaft)

So its a little smaller then the Feigao.. I am really anxious to see the 1015 at HC though..

~Kev
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Old Aug 08, 2010, 08:50 AM
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A 12mm inrunner for the um planes seems like serious overkill. Will the stock brushed pinions fit on the 1015 inrunner?

I'm still not convinced it's a better option for um planes than this one: http://www.hobbyking.com/hobbyking/s...earbox_GPS-C03

I did rough math before, and its feasible to reduce the overall weight of a plane using the mini geared outrunner, 0.7g esc and 240mah hyperion 1s packs. Can't beat more thrust and less weight!
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Old Aug 08, 2010, 11:50 AM
Foaming at the mouth..
darksiede's Avatar
USA, KS, Topeka
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Quote:
Originally Posted by wparsons View Post
A 12mm inrunner for the um planes seems like serious overkill. Will the stock brushed pinions fit on the 1015 inrunner?
Don't know yet, HC has been having issues restocking the 1015, so I can't get ahold of one..

Quote:
Originally Posted by wparsons View Post
I'm still not convinced it's a better option for um planes than this one: http://www.hobbyking.com/hobbyking/s...earbox_GPS-C03
The 12mm inrunners come in right around 10g, heavier then the C03 for sure, but definitely offer more power.. Obviously the 1015 is 5.1g, but I can't do anything with that motor until I can physically receive one.

Quote:
Originally Posted by wparsons View Post
I did rough math before, and its feasible to reduce the overall weight of a plane using the mini geared outrunner, 0.7g esc and 240mah hyperion 1s packs. Can't beat more thrust and less weight!
The C03 costs $23 not counting shipping or an esc, and for $23 shipped I got the old version walkera 003 12mm inrunner and an esc, the new version 005 costs $24 alone but may not be needed is the cheaper old version works fine in this application.

The best review of the C03 I've read says 42-48g of thrust.. It also has a fragile gearbox, propshaft and wires.. The 12mm inrunner will get over 75g of thrust on a full pack, and never less then 62g thrust before the battery hits lvc. It may be heavier, but for under 12g of more weight, I'm going to be getting nearly 2X the thrust. AUW would end up around 40-42g on a Sukhoi XP, and will prop hang the entire pack. Some weight can be saved also, once the setup is proven by eliminating the connectors between motor & esc, trimming the servo lead length etc etc..

~Kev
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