Servo power?

What size servos should I use for a 90", high wing, 25cc gas/petrol trainer/camera plane? STOL, Mildly aerobatic.
Servo Types Standard : about 3.3 KG/cm torque Medium torque : BB 5 to 6 KG/cm torque High Torque : over 10KG/cm torque
Does this sound about right as the *minimum*?:
Throttle --- Standard Ailerons (a servo each) --- BB medium torque Rudder (+tailwheel) --- BB Medium Torque Elevator --- BB medium torque Flaps --- High Torque (or 1 BB medium for each flap)
Also, Is one 6V (5cell nimh) 2300 mah battery pack enough ?
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| What size servos should I use for a 90", high wing, 25cc gas/petrol | trainer/camera plane? | STOL, Mildly aerobatic. | | Servo Types | Standard : about 3.3 KG/cm torque | Medium torque : BB 5 to 6 KG/cm torque | High Torque : over 10KG/cm torque | | Does this sound about right as the *minimum*?: | | Throttle --- Standard | Ailerons (a servo each) --- BB medium torque | Rudder (+tailwheel) --- BB Medium Torque | Elevator --- BB medium torque | Flaps --- High Torque (or 1 BB medium for | each flap) | | | Also, Is one 6V (5cell nimh) 2300 mah battery pack enough ?
80 inch Robinhood, (Curtis Robin stand off scale) that I bashed by removing the dihedral, beefing up the spars with spruce along with using hardwood in the cabin area, plus adding flaps and functional struts.
I used, T-Standard, A-BB Med, R-BB Hi, E-BB Hi, F-BB Med for each flap.
A 1400Mah NiCad battery has been sufficient for 10 years. ( The packs started out C size and are now AA size for the same capacity) I started out with a BB medium torque on the rudder but it didn't last long flying off of grass as well as pavement.
BTW it is powered by an OS BGX-3500 (2.1 CI)
--
Jarhead




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Jarhead wrote:

Okeydokey, thanks for giving me a rough idea.

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Ted shuffled out of his cave and grunted these great (and sometimes not so great) words of knowledge:
Here you go. Plug the information in and it will tell you what you need. There are also several other nice calculators there.
http://www.csd.net/~cgadd/eflight/calcs_servo.htm

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Ted Campanelli wrote:

Nice one!

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On 15 Nov 2006 03:46:30 -0800, snipped-for-privacy@digiverse.net wrote:

I dunno, but I strongly believe that any and all "camera" planes should be electric powered because electric motors don't vibrate a fraction as much as IC engines, especially gasoline ones, and you have the option to eliminate vibration completely by turning the motor off during a photo run, and then restarting it.
Tejas Pedro
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| On 15 Nov 2006 03:46:30 -0800, snipped-for-privacy@digiverse.net wrote: | | >What size servos should I use for a 90", high wing, 25cc gas/petrol | >trainer/camera plane? | >STOL, Mildly aerobatic. | | I dunno, but I strongly believe that any and all "camera" planes | should be electric powered because electric motors don't vibrate a | fraction as much as IC engines, especially gasoline ones, and you have | the option to eliminate vibration completely by turning the motor off | during a photo run, and then restarting it.
That would be ideal, yes, but the electric equivilent of a 25cc gas engine would cost a bundle.
Like it or not, above a certain size, going electric costs a lot more than going glow or gas. Things are certainly improving, but the cost difference is still pretty signifigant, and it gets worse if you already have all the gas/glow support equipment you need, but don't have the electric support equipment.
As an example, I'm currently assembling an Ultrastick 25e. Motor $90, ESC = $115, a single battery pack is around $130, though I'm cheating a bit by going with emoli cells I've already got. Setting up a similar glow setup for this plane would cost $80 for the engine, $10 for a servo and $10 for a gas tank -- and this is still a small plane by glow standards.
(On a side note, I'm really impressed with this ARF, though I haven't flown it yet. I'll bet if I had all my tools ready to go, ESC all soldered up, battery pack ready to go, I could have assembled it in a single hour. No glueing needed whatsoever!)
--
Doug McLaren, snipped-for-privacy@frenzied.us
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Doug McLaren wrote:

So build something smaller.
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Doug McLaren wrote:

You hit it pretty much on the head. The plane will have to be a platform for a semi-pro video camera likely to weigh about 2lb. The engine will be anti-vibration mounted, as will the camera. The plan is to use it for footage for a travel documentary.
The ultimate challenge is to fly it through a rock arch in some sea cliffs. It means that I will have to fly it into the arch and set it for a slight climb and turn when the failsafe kicks in as it loses radio contact on the other side, it should regain RC contact when it comes into vision again. I think that would make quite a spectacular vid (even if it piles into the cliff!). Obviously I'll film all the less risky stuff first....
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snipped-for-privacy@digiverse.net wrote:

I could carry 2lb payload on my 200W electric 60" old timer..just.
Certainly a 5lb plane with 350W - an easy sort of cheapish electric setup could carry 2lb. Something like the venerable senior telemaster is in that ball park. Power train about $200
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The Natural Philosopher wrote:

The brand new strimmer engine cost me 30 ($50 US)
It needs to be STOL, fly in windy conditions, cope with turbulence and be able to carry floats as well, with a decent climb rate. The video camera may need to be on a tilt-swivel mount. I already have small electric and glow planes (glow is out because the fuel is unobtainable) I can always fork out for a big electric setup at a later stage, but right now this is the cheapest and favourite option. The thing is, the locals there might get interested in building some, and strimmer engines are widely and cheaply available. Conversly, glow engines would have to be got mail order and expensive glow fuel would have to be delivered by ship because it's volatile, lead time 4 weeks. I'm fed up with glow engines anyway.
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| The ultimate challenge is to fly it through a rock arch in some sea | cliffs. It means that I will have to fly it into the arch and set it | for a slight climb and turn when the failsafe kicks in as it loses | radio contact on the other side, it should regain RC contact when it | comes into vision again.
You might not ever lose contact -- the cliff will probably attenuate the signal greatly, but unless you're really far away enough of it might still diffract around the cliff to control the plane.
Of course, it's hard to fly a plane you can't see, so ...
| I think that would make quite a spectacular vid (even if it piles | into the cliff!). Obviously I'll film all the less risky stuff | first....
Sounds like a great way to destroy a plane! Be sure to have somebody filming on the other side so you can catch the crash!
--
Doug McLaren, snipped-for-privacy@frenzied.us
Only those who dare to fail greatly can ever achieve greatly.
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On Wed, 15 Nov 2006 18:34:48 GMT, "Doug McLaren"

Do you want good pictures or not?
Electric motors vibrate less, much less, than IC engines, and can be turned off and on in flight, a huge advantage especially for quality minded photogs. It's laugh out loud funny to me that so many rc'ers can sink very many hundreds or even thousands of dollars into the brand new latest hobby gadgetry and yet somehow manage to continue to gripe out about the cost of electric power. Guy with a 10K plane and a 2K radio, "electric is too expensive." Get real, bro.

My vision of a camera plane is that of a 100+" span sailplane-like platform. "Old" electic flight technology (meaning much less expensive) motors & batteries would be more than sufficient power.

See? You're really just another electric fan! <g>
Which, btw, I'm not. I gotta smell that exhaust. If I ever go all electric I'll need to have a downwind camp stove nearby boiling glow fuel.
Tejas Pedro
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Random Excess wrote:

Of course. Videos, not just pictures.

Sure, but it needs to carry a broadcast quality video cam.

Sure, but it won't carry a 2lb pro video cam, possibly on a swivel-tilt platform, nor will it cope with windy conditions or flying uphill fast. You can fit a *still* or even a small consumer video cam onto pretty much any plane nowdays, but to shoot pro vids where I want to do it, the plane I'm building is my first choice.

Lol! I have 'lectric gliders too and some 400 size own design funplanes. I prefer peaceful electric to stinky, dirty glow. I left the pull start on this petrol engine (quite light one) and it starts with two pulls. No messing with glow batteries and needle valves. The fuel is cheaper too. Anyway, you can't get glow fuel where I want to film.

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snipped-for-privacy@digiverse.net wrote:

You should see some of teh slope sorarers mate! They are FAST as greased weasel shit.

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On 15 Nov 2006 12:06:32 -0800, snipped-for-privacy@digiverse.net wrote:

It sounds like an interesting project. Good luck and I hope you have fun with it.
Tejas Pedro
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Random Excess wrote:

Cheers, I'm already having fun designing the plane.

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| >Like it or not, above a certain size, going electric costs a lot more | >than going glow or gas. | | Do you want good pictures or not?
Of course. And I want a pony too.
In any event, you can get pretty good pictures with a gas/glow plane by building in an appropriate vibration daming mechanism into your camera mount. Then all you have to worry about is the exhaust from your engine fouling your camera ...
| minded photogs. It's laugh out loud funny to me that so many rc'ers | can sink very many hundreds or even thousands of dollars into the | brand new latest hobby gadgetry and yet somehow manage to continue to | gripe out about the cost of electric power. Guy with a 10K plane and | a 2K radio, "electric is too expensive." Get real, bro.
I was thinking more of a $300 plane, $50 radio and $50 camera, but hey, get real bro.
If you've got $10k to put into a plane, you should be able to get great results, IC or electric.
| My vision of a camera plane is that of a 100+" span sailplane-like | platform. "Old" electic flight technology (meaning much less | expensive) motors & batteries would be more than sufficient power.
Yes, that would work nicely. And contrary to what the other poster said, as long as you watch the CoG carefully, a somewhat high performance 100+" glider certainly should be able to tolerate another 2 lbs of weight without much trouble, though if you mount the camera underneath, I wonder about landings without a landing gear -- I guess you'd want to add one.
| >(On a side note, I'm really impressed with this ARF, though I haven't | >flown it yet. I'll bet if I had all my tools ready to go, ESC all | >soldered up, battery pack ready to go, I could have assembled it in a | >single hour. No glueing needed whatsoever!) | | See? You're really just another electric fan! <g>
Absolutely. But I'm not an electric (or glow) fanboy -- I know the advantages and disadvantages of electric vs. IC.
| Which, btw, I'm not. I gotta smell that exhaust. If I ever go all | electric I'll need to have a downwind camp stove nearby boiling glow | fuel.
I recall seeing some scents to add to your glow fuel at the R/C car shop. Seriously. I imagine it's only a short matter of time before somebody makes some nitro-smelling cologne, if it hasn't already been done.
--
Doug McLaren, snipped-for-privacy@frenzied.us Nature abhors a vacuum. So does my dog.

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Coincidentally I was in Austin last week at one of the Hobbytowns looking at that plane,the ultra stick 25e. I ended up with a Formosa glider which I will power with existing parts. Went by the Cedar Park shop(rc cars mostly) and bought an Evolution 1.0 NX for $150. mk
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A fellow in our club just maidened the Ultra Stick 25e, and loves it. Of all of the electrics I've seen, this one is pretty awesome. I know very little about electrics, but this plane will serve to spur me into learning more about them. The plane is just dead solid. The guy who has it is not usually impressed with electrics, but I sense a difference in his attitude with this one. Of course, he has more motor than he needs on the plane, but it really performs extremely well with it. I believe he said it is an AXI that is two steps over the one which he was intially considering.
I'm still sticking with glow for now, but I have ventured into the dark side in a couple of small ways. We'll see how those "ventures" go.
Harlan
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