Hi,

The Poulan 46cc are a little more power than I can use. Does anyone know if the smaller Poulan chain saw motors are as easy to convert as the 44/46 Poulans, and good runners?? Something in the 30 to 36cc range? How about the Patriot 1900 or the Realtree 2075 saws? Do they have "drop engine out, bolt a prop on and run" setups like the #2750 46cc saw?

Thanks,

AV8TOR

Im not sure if the smaller engines are any lighter ??
To much power??? what is that??
Adam

Av8tor,

The smaller poulan saws don't have the mag bolted to the cylinder. However, CH ignition kit bolts right to it for about $150.
Makes them MUCH lighter without flywheel.

However...the Homelite 33 DOES....Look for the RS engines Brute 33... VERY easy conversion...

Your other option is the Ryobi 31cc.

Those are the two easiest conversions around the 30 cc range.

For ultimate lightweight gas power though...I have an RCS 1.40 that I think is the BEST small gasser I've run to date....SUPER light, compact, and powerfull enough to drag my 12.5 lb H9 Edge around the sky with ease.... It was worth every extra penny that I spent in NOT having to mess with the conversion issue...true to the meaning "bolt and fly"....

What airframe are you looking to fly?? Maybe we can offer your best "proven" solution??

Best of Luck!!
CrazyHerb

As much as I like the Poulan chainsaw engines, they are a bit large for 1.20-size aerobats like the GSP 72" Katana you're thinking about. I'm sure it will fly it like a rocket and 3D like there's no tomorrow, but normal aerobatics will not do well. Heaven forbids you get a flameout near terra firma... it will drop like a rock.

The 46cc and 42cc are perfect for 25%- 27% aerobats, planes like the GP Wagstaff Extra, H9 80" Cap and Kangke Texas Hurricane. Problem with the smaller Poulans is that they use the exact same crankshaft as the 42cc, which is BEEFY. Even the lowly 33cc will end up weighing around 4lbs or so. No big deal on a 16lbs plane, but a little heavy for something that's suppose to be 10-12lbs RTF.

For 1.20 size aerobats, look at equivalent gassers to the G-26. I just got to run my two Kioritz 25.4cc (exact same displacement as G26) with SynchroSpark CH ignition. They both turned an 18x6 at around 7500rpm, and should get better as they break in some more. RTF weight is around 3lbs.

The new Ryobi 31cc and the Homie 30cc, both twin ring engines, might also be viable choices. The Homie needs a judicious trimming of excess metat. Done well and with electronic ignition,both conversions should come in at a little over 3lbs.

I also like the 30cc and 33.4cc Echo chainsaw engines, but I don't know how easy they convert, as they are not popular candidates for RC conversions. They sure do look lightweight, though.

Volfy:

My Ryobi 31 with trimmed flywheel, stock muffler, wood prop, and Paragon mount & spinner weighs in at 4 lb 10 oz. Lose the flywheel and you're down to 4 lb even. Lose the steel muffler and add an aluminum one and maybe you're at 3 lb 12 oz. Add an electronic ignition and you're back at 4 lb. I don't think you can put a Ryobi on a good enough diet to ever get it down to 3 pounds! But my nice little 25cc Poulan Featherlite is at 3 lb WITH trimmed flywheel...

Craig, I am going off of my Ryobi 31cc, which I converted to glow. The setup as shown in the picture (minus the spinner) is just under 3lbs, according to my 5lbs postal scale. The CH Ignition module I have for it weighs less than 4 Oz. If I use a light weight battery pack, I can fairly easily stay under 3-1/2 lbs.

The engine in the picture also has a lot of the unnecessary bosses and appendages ground off. I could probably take off another 1-2 Oz. if I really wanted to. Also, the B&B muffler stingers most likely can be shortened. Plus it really only needs one stinger anyway. It's substantially quiter with one pipe blocked off and I only saw 100-200 rpm drop.

Wow, I'm going to have to finish my Tecumseh 49er. Right now, less muffler and ignition, it's at 3.4lbs. I can still take some more off here and there. Gotta make the sensor mount and fire it up!

The Homie 30cc needs a lot more pruning, as I mentioned above. Here the work I have done on mine so far. The bare short block with only the spark plug weighs in at 2 lbs 3.7 Oz. so far. That is without the flywheel and prop nut in the picture. I don't like to run my conversions on flywheel. It's on there now as a crank turning knob.

I'm sure I can get the short block to under 2 lbs, which puts me back even with the Ryobi 31cc.

The potential is there, if maybe requiring a few more clams and a couple jars of elbow grease.

Volfy:

I'll agree 3.5 lb is very doable. I think an ignition Ryobi UNDER 3 lb (with muffler, prop, and spinner) would still be quite an accomplishment though!

Quite a carving job you did on the homie!

The homie "33" has no trimming required and seems to me to have ALOT more power than the 30cc weed trimmer motor.But the 45cc homie apears to have the same block as the 33cc just a bigger cly.!?? I just got done converting the 45 and that thing really has POWER!!

Thanks for all the input guys.

I'm still thinking about the Poulan though. That Katana seems to consistently come out tail heavy from other posts I've seen, and I'd rather add an ($80.00) Poulan than dead weight.

If I do it, and I probably will, I'll let you all know how it comes out. I'll keep the engine as light as possible. It may take me a little while dollar wise to get it all done, but this sounds like a fun project.

BTW, I just ran my little Kioritz 16cc conversion today. I got 7000 rpms on an APC 15 x 8 prop. This is with the engine completely stock except for a muffler I made out of a butane refill can, and a CH ignition "kit" that I bought and installed. I'm really pleased with it. I would post a weight ready to fly for you, but the digital scales I just bought doesn't work. (Neither does the Glo Bee Tach I just bought!!) Had to fall back on my old reliable; my ACE R/C analog tach!

Thanks again and have fun,
AV8TOR

If your looking at using the CH igntion...
I'll second the little 33/34 cc poulan...

I have a Poulan 2150 34cc I bought for 40 bux...and it runs like a little raped ape...

You gotta stay with the PORT inducted conversions for the extra punch....chainsaws are the way to go....think about thier normal use of operation....string trimmers (governed/regulated/reed valve induction for longevity)......chainsaws....on the other hand..all out wide open baby!!!

They just have a whole different "feel" to them....

Not to bash the newer twin ring ryobis though...I have two....can't wait to get them flying...

When i ran the two trimmers right after each other, you could tell just by the sound .....twin ring is much "pop"ier sounding....cooolll!!

Best of luck, keep us posted!!
CrazyHerb

Thanks,

You know, it is funny how things work out. A good number of years ago, I was flying at a little country field out of Prescott, Arizona. A guy showed up with his rather large (for that time) plane. He toted the plane out to the flight line with nothing more than his transmitter. He fired it up and wow, did it sound different. He proceeded to take off and fly like a homesick angel. That was my first exposure to "gas", and I thought to myself, someday, when I have time, I'm going to do that!!

Now I am in the thick of it, and it is too much fun!

Take care,
AV8TOR

I don't know about the Homies, but the 33cc-46cc Poulan chainsaw engines do need an engine mount , whereas many of the weedies can be bolted directly to the firewall. Depending on which mount you use, that could add another 6-8 Oz. to the weight of the engine assembly.

I'm not trying to put down the Poulans; I have both a 46cc and a 42cc. I just don't think they are good match for 1.20 class aerobats.

BTW, The H9 80" Cap is on clearance for $299. Perfect for the larger Poulans. Not for me unfortunately, my wife will go on strike if I heap another big ARF box on top of my existing pile.

Volfy: Where is the $299 sale? Thanks Capt,n

http://www.chiefaircraft.com/cgi-bin...els/Model.html

Hadn't thought about that volfy...
For the 1.20 Katana threre's really no "perfect" converstion style motor that I can think of for this plane that would make it perform up to it's aerobatic potential.

HOWEVER, for a bit more money and less fussing with a conversion I'm totally blown away with how my little RCS 1.40 performs.

I'm currently running my RCS on a 13 lb H9 Edge with a Bambula 16x8. It pulls it around just fine....I have enough vertical to not even worry..pretty much unlimited vertical if I enter the up-line with some sort of airspeed. Crawls out of hover....I'm more impressed with the motor than the plane that's for sure...It's very "scale-like" in power to the full size Edge. Which by any means is not too shabby!!

I run a smaller 8 oz tank and have yet to run out of fuel even after 15 min flight.

To avoid the extra weight of an engine mount, maybe the FPE 1.3 is a decent choice....I haven't heard much about this motor though. There's also the newer Zenoah G-26...but I think it's a little heavier.

I would agree though, for even the small Poulan...you need 1100 square inches (min) of wing for good flight performance. Keep it under 10 lbs and the RCS is awesome....

So, that's kinda what I'm looking for now...an ARF that will build up less than 10 lbs with RCS 140 attached and more than 1100 sq in. Yet, still "scale-looking" aerobatic.

That would give me 1.5-1 thrust ratio.

Best of luck!
CrazyHerb

Herb, what RPM does the RCS 1.40 turn with the 16x8? Sounds like a good engine.

The FPE 1.3 is based on the Echo (Kioritz) 21.2cc engine. The big E letter cast on the cylinder gives it away. My Echo 25.4cc has the same exact letter on it. It's a little weak for a 1.20 aerobat, but I sure dig that cute wrap-around muffler though. I have an Echo blower that has this same engine in it. If some part in the blower ever breaks, I'll liberate the engine in a heartbeat.

The FPE 2.4 at 3lbs, however, looks like a good match for 1.20-1.50 size Extra or Edge. Then again, it's rather pricey.

Still, I like the new G26 the best. It's not priced in the stratosphere like the other small gassers. The weight of it doesn't lend itself well to the all-too-popular 3D stuff, but then again, I'm not a hovering kinda pilot. I happened to think the airfoil on an airplane should be put to work.

Volfy,
You know....I've been wanting to get RPM's from my motor but I always forget to grab the Tach....

I really want to know myself....

This little motor pulls great with the Bambula 16x8, but I want to try a couple different ones for giggles.

Props I will be trying are:
MA Wood Scimitar - 17x6
18x6 TopFlight Power Point with tips clipped and squared to 17x 6
APC 17x8
APC 16x8
Bambula 18x6 (just curious)

I'm really impressed with these Bambula props.....they're thick...but the airfoil on em...just pulls like mad!!

I'll post numbers as I get them....

CrazyHerb