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Old Apr 14, 2012, 10:48 PM
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Quote:
Originally Posted by Edwards Rc View Post
Lighten up dude.. I was being sencere... and this was not even my problem...I just rebuilt my A10 with $15 servos... use a DX8 and a Ar8000 receiver.. mine are smooth and dont jitter..
Can't help myself.... need therapy
Ed price and jitter or no jitter says little to the quality of the servo.

Jitter is easily programmed out simply because digitals have such a greater range of frequency control; 500mHz on digitals to 50 mHz on analogues. If they dead ban program several steps out so that the servo is less responsive it won't jitter. But its holding power and resolution would still be magnitudes better than your equally cheap analogue so to you its great and it actually is. Just about any cheap digital should be a big improvement over previous common comparisons with analogues. Because the components are shared between digital and analogue via manufacturing savings, both have improved but the markets costs fluxuate because there are less middle men so from some the price goes down. Traditional sources, thinking like oil barrens, don't want to reduce the percieved market price so they play on the idea that its more expensive because its better, where what they are selling is often being made in the same plant as the cheap one made up of the same thing. Thus pricing is becoming less of a tell as to quality. ESCs are a good example of that. You just have to find out if the quality is actually there or if its a box with a monkey inside......
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Old Apr 14, 2012, 11:48 PM
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United States, CA, Lancaster
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Good stuff Max...

So I need you electrical expertice.. BUilding up this A10 electrical system, gathering the componets..

So this is th LX A10.. I am installing the OEM 70mm 6 blade fans and 2100kv motors.. I have 2 castel 80amp esc's (no Bec).. the power leads off the ESC;s are 14 guage.. as you probably already know, the run up to the battery is quite long.. 28" to the front of the Battery Tray..

Tell me if this sounds right to you.. I was planning on soldering the 14 guage ESC's power lines into a Y using 10 guage wires from that Y up to the Battery tray ( 28") and soldering 4mm Bullet connectors.. This runs off a 6s 5000Mah 30-40c Lipo..

The only question, I have before your comment, it what is the name and size female connectors to I need to order for the ESC to Motor plugs? The motors already have male connectors on them.. they are small.. maybe 3mm, but not sure if there is a standard used on outrunner motors...

So Max, tell me if I'm doing something wrong here in my plan.. if so, what I need to change.. thanks for the expert help..
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Old Apr 14, 2012, 11:55 PM
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But I don't even have an A-10 Offline; I'll PM you since this is the SU thread.
Quote:
Originally Posted by Edwards Rc View Post
Good stuff Max...

So I need you electrical expertice.. BUilding up this A10 electrical system, gathering the componets..

So this is th LX A10.. I am installing the OEM 70mm 6 blade fans and 2100kv motors.. I have 2 castel 80amp esc's (no Bec).. the power leads off the ESC;s are 14 guage.. as you probably already know, the run up to the battery is quite long.. 28" to the front of the Battery Tray..

Tell me if this sounds right to you.. I was planning on soldering the 14 guage ESC's power lines into a Y using 10 guage wires from that Y up to the Battery tray ( 28") and soldering 4mm Bullet connectors.. This runs off a 6s 5000Mah 30-40c Lipo..

The only question, I have before your comment, it what is the name and size female connectors to I need to order for the ESC to Motor plugs? The motors already have male connectors on them.. they are small.. maybe 3mm, but not sure if there is a standard used on outrunner motors...

So Max, tell me if I'm doing something wrong here in my plan.. if so, what I need to change.. thanks for the expert help..
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Old Apr 14, 2012, 11:58 PM
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Hi Edwards Rc.
Do your self a favor and install a separate BEC (Turnigy 7.5A is a proven solution for me).
Also, install 2 capacitors per ESC, since you run long power leads.
Finally, add anti spark protection (2 Ω, 2W resistor) to keep your connectors clean.
Happy landings
Takis
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Old Apr 15, 2012, 01:08 AM
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I do have the A-10!!!...Cyclone 2500kv motors on 6S with Sapac fans in the stock LX housing...I'm using 80 amp ESC's and have 10 guage wire to the battery...I soldered all of my connections between the ESC's and the battery as every place you install a connector there is resistance...I'm using EC-5 connectors for the battery to the ESC's...I'm also running a separate UBEC...As a general rule---You don't need a capacitor pack when running 6S and under...Higher voltages are where you will see ripple current as being a problem with long battery leads...An anti spark connection is a good idea as every time there is a spark the connection gets a little bit higher in resistance due to spark pitting of the connection..Here are a few pics of my weathered A-10....I still have a little left to weather and clear coat...Note that the elevator/horizontal stab hasn't been weathered yet..

Kevin
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Old Apr 15, 2012, 02:21 AM
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NIce Job Kevin, I do have a 10 bec/cc to install. I'm also running 80amp Castel ESC's and will do the same soldering as you mentioned.. I'm not familar with the EC5 connectors, but will get them as I know Deans are not recommended..

I don't know that side or the name of the connectors are for the ESC to motors plugs, but look to be 3mm as the motors connectors are factor installed, but don't say what are. I got the stock 2100KV motors and EDF's..

I just finished modifying the airframe and installing all metal gear servos and RC landers retracts.. I need to get the graphite for my weathering.. was wondering what matt spary you were using to seal the weathering in..

thanks for the reply, guess I should havedone this over on the A10 discussion, since this is for the SU35.. which mine is now ready to fly.. waiting for warmer clamer weather..
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Old Apr 15, 2012, 06:01 AM
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Max, you are wrong about the leverage on outer holes thing.....
If you have a setup completed, to give you your required surface ranges (which thus would require some ratio of servo drive multiplication or division), it does not matter if you move the PAIR of horns ends miles outwards, or miles inwards, the resultant leverages and torques remain identical. You have to move them outwards (or inwards) in unison to keep your prior chosen surface range.

The maths (geometry) of moving the hole used (remember they have to move both ends to maintain surface range) gives the exact same results.

eg Moving out on the servo end would increase leverage, load, torque.... except it is equally offset by the receiver ends reduction in load,torque required due its gain from the leverage of moving it outwards too.

But the overall benefit of moving more outwards in holes is that freeplay - which is a constant if you have some - has less effect because the ratio of the total movement around the now larger arc of travel, compared to the never changing freeplay amount, 'absorbs' the freeplay to a greater degree.

ie Say you have freeplay slop that is 0.4mm. Freeplay slop of clevis to horn hole - not slop in the servo gearing (that is a different issue to correct another way).
If you have an inner hole setup that has an arc of travel that is 6mm, versus a further outward holes arc of travel being 12mm, then the error resultant in the sytem is HALF for the outer hole setup.

If you have servo slop/freeplay.... your only option is to change the servos!
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Old Apr 15, 2012, 06:04 AM
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Originally Posted by tmsn View Post
Here's the latest weathering on my SU35. It looks pretty good in sunlight. It's my first airbrush job in a very long time, I think it came out well. Also put in a smaller pilot figure someone gave me, looks a lot better than the stock giant

I've destroyed two main landing gears this week. One lost the anti-rotation pin while slowing down after a perfect landing. I changed it, and the second time the wheel disintegrated during take off. I didn't even notice it until I landed it and noticed the plane veering left. Thankfully it was another near perfect landing so it didn't do any damage whatsoever.

I need to replace the main gears, they keep buckling like this. I think the 55C 5000Mah battery might be a bit heavier than the plane is designed to handle.
very nice paint job tmsn, I though just glassing my suhkoi would be impressive but that's an awesome paint job. seriously i'm going to have to buy another plane and stand in line behind vince to get you to paint it. also where is the airfield that you fly from? I thought rancho and perhaps this small private airfield i found were really the only places big nuff to handle this plane.

just some random updates on my noob flying experience...had about two or three perfect flights since the video of me landing was taken. i've also had some unfortunate setbacks...like v8 i had the pin on the main gear get loose - mine happened on takeoff so fortunately i didn't get airborne. the reason i didn't get airborne is that the cheater holes on the opposite engine sucked up the metal pin and poof no more fan blades.

following this i put a metal screen on my cheater holes. plane flew great with just the holes screened and i haven't had any further issues with FOD, and yes i fly from a dirt runway, and no it was the pin - i've sucked up rocks and dirt before but nothing complete got rid of the fan blades this quickly.

i've also determined that the stock 4000mah battery is insufficent for fun. this after i ran out of juice while on approach when it was windy and sorta raining. yeah i'm crazy. crashed, took off the nose right in front of the canopy and landing gear which i attempted to retract upon realizing that i was dead stick...repairs are almost complete.

was thinking of switching out to the cs-10 70mm fan blades...sorry for asking again but what kind of esc's would i need to run with stock motors? is there any gain in thrust or are the change sun blades all about sound?
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Old Apr 15, 2012, 06:24 AM
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When I ran up my fans, there was a terrible 'graunchy' noise... hmmmm, blades hitting housing I would expect.
On disassembly... yep, big scrape marks around the housings.
Checking the blade clearances, the motors were bolted in off-centre by some millimetre, or fraction of. Enough to have one side the fan giving about a 2mm gap and the other side a 1mm gap.

You can't move the motors, as their bolt holes are a tight fit to the bolts. So I drilled them out to 3mm (they seem to have been about 2.5mm or so) to allow re-centering of the motors. Problem solved.....

But doing up the shaft nuts was verging on impossible.... as is the common case of shafts using the 'tapered clamping bozo system' !! That was disappointing to see they used that on a 6S (1500w approx) type system. You really want motor flat(s) and grub screw shaft mounting.

So for now I just made flats on the tip end of the rotor shaft, so that it can be held with a spanner/shifter whilst also using the same for the nut. This allows maximum torque ability, whilst also assuring the rotor, motor, shaft have no way of changing alignment as you tighten it up.
How did anyone else tighten it up in any useful manner? I hope not by holding/clamping the motor can !!

As it turns out I have ONE of the exact same fan units (from Hobby King) and it uses a twin grub screw clamp system for its rotor shaft instead. So I can get those shafts if I need to.... and/or want to. But I have another solution I will use....

I also tested a CS10 rotor in there and it is a perfect fit. (I had already set my "same fan/housing" up as a CS10 rotor version for another plane anyway). But I would move down to 2100KV motors for that - which I don't have for now, so that will have to wait. Or rather, I think the maiden flight will be waiting until I get more CS10 rotors and 2100kv motors for it.....
I have converted two aircraft to CS10's and they are 5,234,231 times better sounding!! LOL. It basically turns an "Is that a flying leaf blower?" into as close to a turbine sound that electric fans can probably get - for now. So it is a no contest that this Su 'needs' them to move it closer to a scale version of the real thing - in sounds terms.

It is best to keep the stock housings because they are of course the perfect fit into the plane anyway. You just drill a 3.3mm hole/slot into the side to allow an allen driver in to do up the CS10 rotor shaft grub screws then.
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Old Apr 15, 2012, 06:40 AM
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With CS10's..... my tests (of many setups - but by no means anywhere near as many as you can make up!!) are showing that to get 1.4Kg area of thrust you need approx 31,000 RPM.
To get this, it depends some reasonable amount on the motor, you need a theoretical 34,000 RPM (as the load will not allow full volts to KV RPM totals). Thus something in the 2000kv area for 6S.
I expect you would find 1800 to 1900kv would give the best result... and say 2100kv will still give the similar end result but will be lower RPM than its theoretical because it won't be able to drive the load fully anyway. And even if one could then it would be much higher Amps than stock.

I don't even know if there are any 28mm sub 2000kv motors (probably are somewhere) so I am going to start out with 2100kv to at least set a known baseline to work it out from better then.

I already know that 5S "optimal" (***) area is 2300kv......
1.4Kg BENCH tested thrust will cost approx 60A for that. In plane will lose X amount of that thrust.
Thus I am guesstimating about 55A to 60A for 6S to get 1.4 Kg or so out of the CS10 in the Su-35.

I have a 2300kv (not the Su ones) that I can do a quick test on for one reference... I will, but I already know that is really not going to be anywhere near suitable.
Also note.. the stock motors are 2300kv, to drive just a 6 blade fan for 1.3 Kg thrust or so, using 50A or so. So right away you can know a 10 blade fan is going to kill those off via its power hunger! (and thus watts and HEAT).
2000kv or a bit lower is required......
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Old Apr 15, 2012, 10:51 AM
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Joined Dec 2010
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I did static test with the cs10 on the stock 2300kv motors and wasn't impressed. Thrust #s were down compared to the stock fan.

Cs10 - 2100g thrust

http://www.rcgroups.com/forums/showp...postcount=1374

Stock fans - 2900g thrust
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Old Apr 15, 2012, 02:11 PM
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Interesting retract mod rotating wheels and 1 piece nose gear door rather than the split doors.

Freewing SU-35 main gear Mod (2 min 21 sec)
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Old Apr 15, 2012, 02:36 PM
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Cool...

Just my opinion after having other aircraft with similar retracts, i.e. the FA18, large T28 with lots of servos to operate doors and ball links to rotate retracts.. things look cool at first, but start breaking down and getting loose..

Though I like scale operations, I have found that the simplier the better for long term use.. unless one just wants to spend alot of time on the bench fixing things..
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Old Apr 15, 2012, 05:01 PM
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Nearly turned my SU35 into a pile of foam bits today. Right after takeoff I rolled and retracted the gear. The second time I tried this I slowed the roll and must have fixated on watching the gear retract....and next thing I know I am split S ing right at the ground. I pulled hard and staggered out in high alpha. Whoa!
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Old Apr 15, 2012, 05:36 PM
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The front gear door would be super simple. No effort really.

But check out those mains and the L stub leg!! That is pretty ridiculous.
How long do you think a 20mm L feeding the main landing gear leg, will last in its required position... before it is forced rearwards to 45deg or even near 90deg!!
That will cop massive forces on landings that the leverage it gives will make sure no attachment methods las tlong!

If he welded it all up (gee, tough job) then it would not rotate... but would rip out the retract from its mounts sooner or later!!

Well..... unless you fly off a hard SMOOTH runway... and grease every landing! Every single time....

The mod sort of looks nice, but would be impractical.

I think he needs to focus on the silly looking pilot they supply first......
"Wow, what a great looking plane! Wow, the landing gear is complex and realistic! Umm, what the heck is that mutant thing in the cockpit???"
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