ChillPhatCat

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:

tIANci

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.

ChillPhatCat

[8D] 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. [sm=spinnyeyes.gif] Still seems like it'd be a cool modification.

tIANci

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.

ChillPhatCat

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.

tIANci

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

ChillPhatCat

I definitely will, I wouldn't want to risk a $1000 power system going without.

tIANci

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!

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 $$$

gunfighterII

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

dashunde

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.

ChillPhatCat

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.

dashunde

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.

hellblastervolly

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

tIANci

The SU26 will hang all day with a YS160 for sure ... its a lovely plane to fly despite not being a pure bred 3D. As for EP v. GP, having used both its down to personal preferrence, there is no end as to which is better etc etc etc. For me I loved all my GP planes but now its all EP, even to my MidWest CAP 232. Still its most real that EP of 40 size and abive is very costly, not as cost effective at GP but some are willing to pay for it.

Back on topic ... 10S on this baby is going to be a blast! I think it will have almost unlimited vertical. With the right set up we are talking at least 17 lbs of thrust.

gunfighterII

Fernando,
How did your Sukhoi balance out with your set-up?

Being designed for glow power, I was curious how much nose weight you had to add.

hellblastervolly

Gun.

So far I place the ESC in the nose under the firewall and the lipo behind where the fule tank was going to be place. I add a tray of ply so I can laid them on it and strap them with velcro straps. The Rx will go as far forward as posible I still have 72 MHz so mine is a little bigger than a 2.4 GHz. I still working on changing the landing gear from the wing to the fuse that will move it forward, I have the old kit the newer version have it on the fuse. I'll keep you posted when it's finish and test the balance again.

Fernando

microdon2

My Feedback: (47)

I have a CG 73" Sukhoi 26m, with a DLE 30 (picked up the plane used). A very nice plane \ engine match. But this morning I had a mishap - the engine stalled, I ran out of altitude and crashed into a tree. And a low-branch hung the plane up, so it didn't drop to the ground. Fortunately - amazingly - there was minimal damage. But the cowl is badly chipped and I have a hole punched in the front of the right wing. Wing is fixable, but would like to find a new cowl. Anyone know where I can get a blue and yellow (more mustard) colored cowl for this plane? Also, does anyone know the exact color blue? I'll need to get some monokote (or Ultracote) for patching. Thanks.

Mike

microdon2

My Feedback: (47)

Just found the Ultracote colors for this plane on the CG site.

Covering Matches Ultracote® Colors:
884 Cub Yellow
873 Deep Blue
877 True Red

Now I just need the cowl...