Carl Goldberg Sukhoi SU-26  
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All Forums >> Electric Aircraft Universe >> 3D Electric Flying! >> Carl Goldberg Sukhoi SU-26
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Carl Goldberg Sukhoi SU-26 - 6/20/2008 2:15:37 PM   
ChillPhatCat



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From: NY
Status: offline 		I've been building this sukhoi for the last 5 years... well it's more like I built it for a year until it was all framed up and every once in a while I put in 5-10 mins. Anyway, I was originally going to power it with a Gas engine and I had the engine in hand, but I decided against it as the setup was just too bulky and I feared it would vibrate the plane to pieces. I sold that motor and recently I've been thinking about converting it to electric.

I was thinking about running an Axi 5330/18 Outrunner on a 17x12 prop and a couple 9cell 3500 mAh LiPo packs in parallel... The plane is a 1/4 scale, 72" WS and is probably going to come out to about 11 lbs on this setup. Motocalc came up with something like 7 mins runtime and power to weight of 1.2:1... is it generally accurate or just good for a ballpark figure? What other motors can deliver similar power?

As it sits now:


< Message edited by ChillPhatCat -- 6/20/2008 2:21:53 PM >
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RE: Carl Goldberg Sukhoi SU-26 - 6/20/2008 3:18:33 PM   
tIANci



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Status: online 		Chill ... the CG SU26 is such a nice plane. The AXI 5330/18 is just nice for her with a 10S set up. I guess on 9S you can get her to turn the 17x12 happily. The AUW of the plane should be in the 11-12 lbs region. The AXI 5330/18 on 10S will happily fly a 15 lbs plane. I think you might get more than a 1.2:1 thrust to weight ratio. Why not try out an 18x10 and 20x10 prop and see how many amps she is pulling? I mean on MotorCalc that is ...

Other motors are your Hackers, Hyperions, Plettenbergs etc

The run time on MotorCalc is based on WOT and the figures are kinda close, I find that the amp draw to be close enough but RPM sometimes off by quite a bit.

Remember on such conversions your CG is an issue, motors are light so you want to get your batts as far forward as possible. With two 9S 3,500 packs in parallel you should have enough weight to place the batteries in the tank compartment.

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RE: Carl Goldberg Sukhoi SU-26 - 6/20/2008 6:05:57 PM   
ChillPhatCat



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Joined: 6/4/2003
From: NY
Status: offline 		I ran the numbers on those bigger props and it cuts a minute or two off of the flight time... 17x12 on a 10s pack should get me to about 80 MPH and ~220 oz of thrust. I was just looking at the 10S 3700 mAh battery packs and they're selling for $400 ea. Still seems like it'd be a cool modification.

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RE: Carl Goldberg Sukhoi SU-26 - 6/21/2008 9:30:51 AM   
tIANci



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Status: online 		Chill ... anything of 40 sized and above for EP is expensive. As for the prop try on MotorCalc something like a 22x12 or 20x12, you want her to pull around 60A if possible. That gives you about 2KW. I suspect that will give you around 16-18 lbs thrust.

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RE: Carl Goldberg Sukhoi SU-26 - 6/21/2008 7:48:53 PM   
ChillPhatCat



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Joined: 6/4/2003
From: NY
Status: offline 		Ouch... those big props draw like 70-75 amps. On a 10S I got 270 oz of thrust, 75 MPH prop speed and 63 Amps draw for a 17x10 prop... that's about 16.8 lbs of thrust.

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RE: Carl Goldberg Sukhoi SU-26 - 6/22/2008 8:13:29 AM   
tIANci



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Status: online 		Chill ... sounds like a good start ... remember to get a watt meter.

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RE: Carl Goldberg Sukhoi SU-26 - 6/22/2008 5:36:53 PM   
ChillPhatCat



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Joined: 6/4/2003
From: NY
Status: offline 		I definitely will, I wouldn't want to risk a $1000 power system going without.

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RE: Carl Goldberg Sukhoi SU-26 - 6/23/2008 2:44:57 AM   
tIANci



Posts: 8453
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From: Kuala Lumpur, MALAYSIA
Status: online 		A watt meter is like only less than 75 dollars I believe. Many here don't use one and motors/esc tend to give. Batteries too ... All the best in your build and conversion!

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RE: Carl Goldberg Sukhoi SU-26 - 6/30/2008 12:01:09 AM   
dashunde


 

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Status: offline 		No way.
Based on its design age I'm going to speculate it is not really a 3d machine, right?
If that is the case, a new 120 or 160ax would have that thing high-speedin across the sky all day long for 1/3 the $$$

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RE: Carl Goldberg Sukhoi SU-26 - 6/30/2008 12:18:53 AM   
gunfighterII



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Status: offline 		dashunde,
Your right, it's not really a 3D machine. A great airplane though otherwise.

Mine has a 120AX with a pump, plenty of power. I think it's around 10.5 lbs

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RE: Carl Goldberg Sukhoi SU-26 - 6/30/2008 4:58:06 AM   
dashunde


 

Posts: 188
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From: lincoln, NE, USA
Status: offline 		I'm envious. I've been thinking about building/buying (arf) that is not really a 3d machine.
See, I can fly 3d/high alpha pretty well... but my high speed/pattern stuff is shameful.
I need a plane that forces me to be smoother and to develop higher speed pattern'ish skills.
And I really like SU's!!!

Yea, ya know, I just think that the virtues of electric power would be lost on that plane, and it would be twice as fun on glow for far less money, same could be said for a 26cc.
I love glow, mostly because it enables wide-open passes time and time again without nary a concern for throttle management, try that with e-power.
And more to the point... I'm never going to build ANYTHING that needs a $300 BATTERY! (insert cuss words around this area)
For that money it better have finely machined parts and make a nice noise instead of being a foil bag full of nasty chemicals... I'll have none of it!!
My limit is 2500mah packs and 40oz planes... cost effective and way over-powered. Good bang for the buck there.
(sorry.. rant off)

All things considered, that SU looks like a VERY good candidate for a small gasser. The 26's don't really make alot of prop-hanging power, and that SU doesn't have the surfaces for it anyway... so why not? Perfect match.

< Message edited by dashunde -- 6/30/2008 5:06:09 AM >

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RE: Carl Goldberg Sukhoi SU-26 - 6/30/2008 5:03:17 AM   
ChillPhatCat



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quote:

ORIGINAL: dashunde

No way.
Based on its design age I'm going to speculate it is not really a 3d machine, right?
If that is the case, a new 120 or 160ax would have that thing high-speedin across the sky all day long for 1/3 the $$$



Eh... back in the day, the SU-26 was 3D... it just isn't up to the standards of what is known as 3D these days. I'm not making this consideration on cost... Over the years, it slowly grated on me having to get all my field equipment out, firing up the engines, tuning the engine and cleaning the model off at the end of the day... Now I charge a couple packs, throw one in the plane and have at it. Plus, it's so very nice to be able to just start and stop the motor on a whim.

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RE: Carl Goldberg Sukhoi SU-26 - 6/30/2008 5:13:15 AM   
dashunde


 

Posts: 188
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From: lincoln, NE, USA
Status: offline 		Chill, I hear you... I do understand the on-field simplicity of e-power, and its worth the extra few bucks on smaller stuff, but this 10 pounder and its $300+ packs? I'd be out on that.

So maybe thats where a (quality) gasser would be the best of both worlds for you?
All you need is a glove for flippin and proper gas can.. no glow starters, igniters or nasty fuel mess required.
Ok, so you'd have to tune it.. but that is far less time/hassle than babysitting packs on the charger.
Besides, once broke in and tuned you've got it made.
Fill, Flip, Fly.

< Message edited by dashunde -- 6/30/2008 5:33:58 AM >

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RE: Carl Goldberg Sukhoi SU-26 - 6/30/2008 6:58:11 AM   
hellblastervolly


 

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Status: offline 		Chill.

The plane look good, I have the same plane on the table and was going to make it a gas plane but change my mind also. I have a Power 160 on it, you can use the Power 110. I think 2 5S 3700 mAh in your case will do better than one 10S and will cost you less. You can go with the bigger prop like tianci said the sukhoi is a sport or aerobatic plane so you need more torque than speed.

Fernando

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