Hi guys

I'm looking for a 50cc or bigger conversion for an 82" 540 that I just picked up.

What do you recommend and where would be a good place to pick one up?

Well, I have tried and investigated many choices and my honest opinion is after two years extensive
search = better buy some good 80cc gas RC engine, for example MVVS, which goes like on the rule
of tumb
Number BHP = (Number CC)/10, i.e.
for 80cc you should get at least 8bhp. And in fact I wander what is the use of 50cc, when they are
as heavy as 80 cc almost. Similar thing like the OS-max 0.61 and 0.91, just "heavy-metal" and
some fuel saving, which is a bit funny.
This ratio 10/1 above would be "nearly" avaialble for the small motorbikes or some big chain-saw
but due to the load they are deigned for their Gear-Box is part of the engine for the motorbikes
and Crankshaft is Very Heavy for the chain-saw. I.e. in neither case you can decrease much
the weight by cutting from outside. Also the Power-vs-Weight is about maybe 5 times worse for
the conversions, unless you spend couple years to get it to let say 2.5 times worse, if you are lucky.

I.e. - the Prices for the Aviation RC Gas engines at the end are not that high as it might look.
Sorry to disapoint you maybe, but I did not want to see more victums of the Idea of Conversion.

Cheers,
Nick

Ralph I have done many 50cc Echo engines which as you know is the BME 50. I am working on a 72cc Husky now that looks like it will weigh the same as the Echo 50 when I am done with it. There are a bunch of them out there so you do have choices and options.

I have a 58cc Stihl backpack blower that made an easy conversion. Scrap engines are a little hard to find but a 65cc blower is also available.

Bill

Hello Tim

What model Husky are you working over?

Some of the Huskys have a plastic lower crankcase and the bottom of the cylinder in the
top journal for the crankcase.
I'm not sure this is a good thing.

I was hopeing that some one would say so and so is selling short blocks for x amount of dollars
and mine is working great.

For $300.00 a G-62 would be pretty hard to beat.

Interesting but isn't it quite too heavy ?
Could please post at least:
The Weight, RPM and on which Propeller ?
And of course some photo if possible.

Nick

Ralph, it is a 272-XP. All metal engine and lite. The Husky parts seem to be a little less than Echo parts. Another thing I discovered is that there are a fair number of aftermarket parts available for them. I have had pistons and cylinders and it is hard to tell the difference. I also have a couple of Partner concrete saws to do. Same thing on them as far as cost and part availability. Time will tell on weight on those.

[/quote]

Interesting but isn't it quite too heavy ?
Could please post at least:
The Weight, RPM and on which Propeller ?
And of course some photo if possible.

Nick
[/quote]
I run with magneto and leave the pull start on but have not weighed the engine in 12 years. Next time it is off the airplane I will weigh it again. It turns 6900/7000 with a 22 X 10 Dynathrust and G-62 muffler and 6900/6900 with a 22 X 8 Dynathrust and Slimline muffler.

The all up airplane weight is 22 pounds.

Bill

Bill,

I checked with the local Stihl dealer that the "naked" engine out of the back-pack is about 5.5kg.
Let say you managed to get it down to 5 kg but I am not sure if that is quite possible - your
measurement will tell sometime when you have it out.
Then the power you are having behind those rpm is around 4.5 bhp calculated and the
thurst is around 12.5 kg i.e. about 27 pounds and I belive you get a good pull up.

But if we look at 80cc ZDZ 80RV which is only 2.3 kg weight and deliver about 6000 rpm
on 26x12 that makes like 7.5 bhp and 20kg thrust, i.e. about 40 pounds and then your plane
should be going like a rocket in the sky, isn't it. Of course this engine cost at least 700 USD
while Stihl is very cheap indeed. How much did you pay for it ? - I guess it is below 150 USD ?

Anyway, my calculations and observations so far a quite discouraging for the Conversions,
they are 2x heavier and deliver 2x less power, i.e. about 4x worse; then 700 USD makes
good sense if a Conversion costs more than 700/4 = 175 $, we live once ... and this
hobby is not cheap in any case. In fact the cheapest ratios are around .90cu planes,
having in mind the price for servos etc. Isn't it ?

Nick

Nick,

'Big Ugly Pattern'

A Stihl dealer gave me the engine in the early 90's. I think it fell off a landscaper's truck before it was used.

No one will doubt that 38% more displacement will produce more power.

There is some doubt about why an 'ugly as sin' overweight airframe should go faster than the structural limits of the airframe.

Bill

Bill,

Surely you have got a very good deal, but that is exceptional, not a general case indeed.

What is the wing load and eventually the stall speed ? Have you driven it to a stall,
maybe you better don't - it looks quite dangerous for this construction to not willing
to get out of the spiral dive, isn't it or you have tested that already ?

Cheers,
Nick

hello ralph,saw your post on rcu.anyway,i have a 61cc husky i converted but im not going to use.(i have 3 61-62ccengines besides this one).i bought it from geardaddy here on rcu.he said it was a running engine then i finished it.anyway,it has a brand new muffler from ken lambert and prop hub.New carb off of G-62.It has very good compression but is dry since i havent done anything with it in a while.i sprayed wd-40 in it not to long ago.it needs a cdi ign with advance but the mount and magnet are already installed and set for 28 degrees BTDC>. it weighs 5-1/4 lbs as in pic.probably to heavy for your 82 inch unless you have quite a bit of wing area.

Nick,

The airplane has 48 flights an flies much like a trainer. It does have some dihedral. I usually set up airplanes to fly soft to match my limited flying skills. A flair and stall from 5' only frightens the landing gear. Wing loading is OK at 35 oz../sq. ft. but it should be flown to the ground. I have not measured the stall speed but it is a big airplane (93" span) so the stall feels reasonable.

Bill

Bill,

That seems pretty light load on the wings, then I can understand the pleasure of flying a big bird for almost free.
Surely that is the Conversion success - Congratulations !

Myself I am not a F3A pilot for sure, I like fast(!) fly because of the windy nature of Scandinavia, here is
seldom a quiet day, usually at least in average 5m/s wind and then the "medication" is faster plane for sure.

Nick

I HAVE 3, 55CC craftsman saw motors that I have been using for 2 years. They pull my wild hare 300 extra 28% and ultimate bipe 29% stright up.[ul]

I have a 1/3 scale spacewalker and I want to install a conversion engine. What engine would be good for it and can I use a home uilt electronic ignition? This plane is going to painted with auto paint.

Bomberbill

I have seen large 1.80 glow engines in it as well as G38 and G45 Zenoahs. You can find several conversion engine possibilities in that range. Poulan 42 and 46cc engines are decent. I have converted a couple 42cc Poulans. Another possibility is the Echo 44cc saw engine. I have one I converted in my son's H-9 Extra 260. Nice thing about the Poulan is that if you don't have access to a lathe or mill you can buy the conversion kit including prop hub and timing bracketry off the shelf from CH Ignitions and you are ready to go. The Echo has more power than the Poulan but in your case that isn't an issue I would think.

[ Thank you fot the tip. I will look into your sugustions. All I want is to say I did every thing that a lot of my flying friends say could not be bone. I enjoy making it from scratch.

Bomberfbill

Yea, we have beat that one to death here on the new Brillelli 50 thread. Read back on that one for some interesting positions and thoughts. There is a lot of Chinese crap comming to market at low prices. They do have a few nice pieces too but you have to be careful as you do get what you pay for. I prefer doing my own as well. The guys that tell you that you can't do something will have their wheel pants blown off when you show up at the field and do what they do with a $200 motor.

Hi, I started a conversion about 17 years ago using a husky 81. I tried to put it in a Byron P-51 with a long drive shaft to the front. The engine never got started and I could see the fiberglass orbiting as I turned the prop. I pulled it out and bought a G62. The engine (81) sits on the shelf till now. I aquired an 88 inch 21lb WW2 plane like the Lysander and when my friend had it, he had a Fuji 64 which gave it hords of power... so much that it cracked the fin when at full throttle. I fixed that problem but with the G38 that is in it right now it needs more power.
The other day I aquired a Husky 61 in real real good shape and only needs bearings on the crank. I plan to convert this over and use it.
I also aquired from another person a Husky 288 but will never in the future I live in will ever have plane to fit it.
Jim