MorePower

I'm scratch building a CG Sukhoi (72.5" wing) and would like to go gas. I was going to put an MDS 1.48 or OS 1.60 in it, but I want to go with gas if I can. How much is too much weight for a engine on this plane (949 sq"). I was hoping to use a magneto Poulan 46cc. About 3.5 to 4.lbs. The advertised weight of the plane "claims" 8.75 to 9.5 lbs.

krayzc-RCU

My Feedback: (31)

i went to a fly in and a flyer was running a BME-44 on his with a 20 x 8 ziner he was just blurping the throttle around doing 3d and easy take offs.

MorePower

That's great... I'm told that the BME44 is within a few oz. of the Poulan. I don't want a "pig" that's got too high wing loading.

with the Poulan on board it should be about 31.5 oz / sq ft.
is that too much...???

JohnnyJ

My Feedback: (1)

Hi!
How about a Moki 20, the same engine as an RCS 1.4.
It will swing an APC 16X8 at 8500 rpm or better.
See

http://www.rcfaq.com/

I have for sale at $525.00 Cdn.
Thanks
John
[email protected]

DGrant

My Feedback: (4)

Moki 20 Johnny? Maybe you mean 2.10 right. Since they don't make a 1.20, at least they don't anymore.

I've got a Moki 1.80 in mine, I can tell you that is plenty for glow, absolutely. I can't imagine a 2.10 in this airplane. Mine goes vertical at will, unchallenged. 18x10 at 7800r's, and it's a tractor.

How about an RCS1.60, although the BME is my choice really. If your going to go the 44, might as well go to the 50, it's only mere ounces heavier. I've got one of these for my Midwest EXTRA, yet to fly, however, I'm sure it's got what it takes. At over $600 all said and done(that's including muff and spinner) it better, and I have no doubt. Don't know though, that' does seem a bit heavy for the plane. My Moki is no lightweight, but ready to fly, it's lighter then the gassers.

JohnnyJ

My Feedback: (1)

Hi!
The Moki 20 SA is a gasser identical to the RCS 140 (1.4 cu).
It weighs 28 oz.
More power than a 120 4 stroke and lighter.
Thanks
John

DGrant

My Feedback: (4)

ah ha...thanks for setting me straight. The 20 is 20cc's. I stand corrected, or better educated
That sounds like it might be decent, although once you've had the power of a strong glow it's tough to find a gasser to compare in this size range. It seems you'd almost have to go the 40-50cc range to come close the Moki glow's. How does that 20 compare with the glows?
I admire the original poster for scratching out a Goldberg Sukhoi. I bet that's going to be one awesome plane. Thanks again Johnny. Take care.

For MorePower, ..how about a ZDZ40, they are a bit less pricey then the BME's, and from what I've read, very powerful for a 40cc engine.

robert

How about a YS 140?

MASTER of 3D

My Feedback: (1)

u dont want a pig with hihg wing loading but u are going to put a gasser in a 1/4 scale with only 969 squares u might want to think a little befoire you are done u will have a high wing loading an it will probaly be higher than u estimate

2lo

My Feedback: (4)

HEY MORE POWER
I too have a CG sukhoi. since your scratch building, I'm in the middle of converting mine to gas putting on a bme 44.
I'm also changing the wing set up. putting the finishing touches to a plugin set up. made an aluminum spar to fit exactly in between the spars, don't know why you couldn't use ply, I just wanted aluminum. made interlocking light ply that fit into the inside of the fuse locking into all the overhanging lips that will attach the wings,using the wing saddle to mantain incidence.
don,t know exact wing area yet,but I'm sure it will be more than enough, span will be at 78".
hoping to finish by this weekend.
mine before weighed exactly 10lbs. With a glow and heavy mount. I don't think I'll gain more than a pound, if that much.

MorePower

If I can finish at 11 lbs with a gasser, I'll be in the low 27's for wing loading. I taken every measure I could to keep it light. I really like the sounds of the RCS 1.4 but I need to keep cost down. That's why I was looking at the Poulan conversion with a Mag. A guy at my field is building one with a 30cc homelite with a CH ingition. I don't think it will have enough power to 3-D.

2lo--- If you think you'll be in at 11# with the BME, I should be at about 12# with a conversion ( 29oz/sq.ft) .... Is that too much????

2lo

My Feedback: (4)

MOREPOWER
I'm no expert, but I think as long as you do your best to keep the loading under 30 you'll be ok for regular aerobatics. I'm trying hard to keep mine down also. This su26 is a floater on landings, just remember that those larger props act like brakes when you throttle back. I would go ahead and land a little hot the first few times to see how she reacts.
I'm hoping to keep the loading in the mid 26's, if I can this thing ought to bee a real blast.
Was using a st2300,bisson,pump, hyde soft mount, mount seemed a little heavy, but I needed it to help achieve balance(that mount is nice it felt like a fourty size engine in there)with servos in the rear for elv.
So far I haven't run across any one else who has put a gasser in one of these.
I getting anxious. keep me posted.

Bob Pastorello

My Feedback: (198)

If I were doing one of these, I'd choose a MVVS 1.60 gasser. I have one now in a 'pattern' Giles look-alike, and at 11lbs +, it is still outstanding. Will turn a 17 x 8 near 8000, and run all day for a buck. Or less.

Checkout my website - "MVVS 1.6 on Viper"....has all the info.

planecajun

My Feedback: (21)

i think everyone is missing the point on this.
he doesn't have the money for all these fancy engines.
the poulan will probally do a great job in the koi.
do watch out for those brakes though. power on landings recommended.

MorePower

Should I build the wing bigger to lower the wing loading??? I still don't know what is considered the "normal" range. Thanks planecajun for bringing the thread "back". I'm stuck with a cheaper conversion or an OS160. Kinda sick of green gooo though.

MiL

if you're going to scratch build anyway, then maybe you should consider scaling the plans up a little bit to be sure that the plane is big enough for the engine you want to use

besides, bigger flies better anyway right?

MorePower

The fuse is done ( except the fire wall ) . I was orriginally going to use an MDS 1.48 but have heard too many horror stories. My thoughts were always for glow, but there's more and more gas power at my club. Unfortunately, there all really BIG. Gas was kind of an after-thought. A G23 is too small, and all the mvvs, zdz, and rcs's are too expensive. An Rcs in Canadian $$ is about $620.00 by the time I get it here.

MorePower

maybe a "used" motor is the way to go If I can Find one...

**Johnny** Is the moki 20 indentical to the rcs or just similar..??

MorePower

Maybe I'm barking up the wrong tree with this plane/engine. I have a bad habbit of trying to save money and then going too far with my final choice.

The objective is to stay "economical" if I can. But, like I said, I don't want a PIG that doesn't fly nice...

DGrant

My Feedback: (4)

I heard HarborFreight carry's the Ryobi 31cc for very reasonable price. Is this true? If so, you might check into that.

JohnnyJ

My Feedback: (1)

The RCS 140 is a Moki 20 in RCS disguise.
Identical except for name tag.
check out this link for MOKI, ZDZ, YS, and Menz

triadaviation.com

and for $ conversions

http://www.oanda.com/converter/classic

John

R.Runyan

Hello,

I had a Saito 120 on my CG Sukhoi NOT even close to the power I needed.
The ad said 8.5# to 9.5# NO WAY!!! I even put lighting holes in some places and with the new engine (Moki 1.35) it still taps out at 11# I could still use a little more power but the Moki is just fine.
I would say that when building the wing, the landing gear needs beefed up alot.
Where are you guys geeting your Fiberglass cowls for the CG Sukhoi?

Moki 1.35 is a good choice and not to expensive I got mine NEW off Ebay and paid $192.50 US.

Hope this helps.

Robin

planecajun

My Feedback: (21)

hey,
for some reason this thread keeps cartwheeling back to other engines. look, the poulan will be fine! trust me! i have a 35% cap that calls for a 80-100cc engine. i currently have a 3w-140 on this plane! i see tons of poeple putting g-62's on the new gp pitts. that plane was never intended for that large of an engine. i have old guys at my field who pick up the tail on my cap and say jeezz what a brick but, i can hand launch the doggone thing straight vertical and fly out of sight. so.....try the poulan, for finance sake. if you dont like the way it pulls.....then save the plane till you buy another engine....but from experience, i think you'll like it...

Chris 540

My Feedback: (3)

I don't think theplane will fly very well with the poulan...

Why in the #### would anyone put a 3W 140 on a 35%??? Do I dare ask what your plane weighs? You are obviously unaware of how well a light plane flies?

planecajun

My Feedback: (21)

the plane weighs right at 31 pounds, and flies more beautifully and gracefully than any light plane i have built to date. im sure if we were talking about a smaller plane being overpowered it would be different but this size plane handles the extra power well. its all a matter of preference but i like my rocket!