KI8FR

1st of all, Sorry about all the miss spelled words the spell checker is not working and I fly allot better then I spell.

I see on this list were allot of ppl are making there home light for plans. I was looking at my engine and I can see that there is allot of room for power. but I can not find any thing on the net or on this list were some one has tried it.

To me it looks as if I can take off about 100,0000 off the side of the crank box.. That would make the presser allot more for bringing in more fuel.

I can see that some one can take off about 10 to 20.000 off the calendar and bring the compression up.

I have not got in to deep with it yet.

Now as the block goes if no one has a mill they can just put something on the side cover on the in side of the block. but the jug would have to be milled..

If this is something that some one had tried let me know. I would not want to put allot of time in something that is not going to work lol

Plz let me know
Thanks Paul

The Raven

A converted Homelite engine will end up around 2Kg (4lb+) if you retain the magneto ignition.

Before leaping into massive modifications start with the simple things. Once the engine is running well you can later pull it apart and try more extensive mods, just be aware that the more extreme mods will kill torque. Extreme mods are better suited to the boat guys turning little props than aircraft spinning big props.

Remove only enough of the front mounting flangs of the case to lighten it. DO NOT remove much material around the coil area, the coil bracket will snap on a hard landing (I know).

Get someone to machine the fins on the flywheel down. Just take them down to the highest solid point on the flywheel. DO NOT snap them off or otherwise remove them as they give strength to the flywheel.

Replace the carb, the stock carbs are way too small to get the best power. A WA-167 is a good choice.

Replace the muffler, it's heavy and restricts the engine. There are pitts style mufflers out there.

Remove the crankcase/cylinder gasket and use a thin layer of gasket "goo". That will give a slight compression increase without affecting port timing much. Any machining you do on the cylinder or case will upset the port timing, which will require further work.

Try to source a "stuffed crankcase" rear cover. You can modify the stamped tin cover but I would rather spend the money on a decent conversion part. I wouldn't machine the rear of the case.

Fit a prop adapter and a 16x8 prop (25cc engine) and then run the engine in and tune it. You should get close to 8000rpm.

I'm about to run in a 30cc (same mods as above) and will see what revs and prop best suits.

Search through the engine conversions forum some more, heaps of good stuff in there.

KI8FR

To late..

I milled off .020 off the jug. then I took a die grinder and took .020 of the top of the intake port.
and cut out the in side of the manafold and put on a carb off a us 25cc engine

I took a pice of still that is .117 and brased it to the in side of the side cover.. This cover is made of still not plastic.

I took out the key to the fly well and advanced the timing 6 degres. Wich it about the thiknes of the key way. Put lock tite on it and put on the prop hub.

With a 16x8 prop I am running at 9164 rpms. but it has a bad idel. It will vibrate bad.. I take it up about 1/4 and it will smoth right out.. I do not know why it is doing this yet.. could be the carb or the timing or the .020 I took out of the intake.. I do not know. I will have to play with it more. I did not think about the tork on it.. I will have to see what the trust is going to be.

Thanks for your in put.... but if it is not going to work it was fun to do lol........

Paul

The Raven

If you milled the jug 20thou then raise the exhaust a similar amount.

IIRC the US Engines 25cc carb is a WA-200. That should flow more than enough.

The steel cover I assume is the pump vent lots of guys modify?

Advancing the ignition will make the idle rougher (on almost any carb equipped engine), it's your choice to live with it or not. I wouldn't want to run 9000+ rpm on a regular basis, my Homelite research indicated that 8500rpm is more than enough for a Homelite that's going into a plane. I'd suggest using a bigger prop.

I'll be running in my new 30cc engine this week, hopefully enough to fly it this weekend. It has only the mods I listed except I'm temporarily running a drilled out stock muffler until the new pitts muffler arrives.

Just for your own info, a 25cc Homelite @ 8000rpm (16x8) will fly a heavy plane 15+lbs. Take a look at my gallery to see the beast I made. It's my first scratchbuild and far from perfect but it's been fun doing it all myself.

KI8FR

This is just somthing I was just playing with.. it was alot of work for what I got out of it.. I just wanted to see what could be done.. I put on a smaler carb.. I do not know what carb it is I cant see it. lol but it is idaling good now. a little ruff but ok. With this carb it is doing about 8762 rpm. I put on a 18x8 on it. the rpms are now at 7202 rpm. that is all the props I got to try.
but like I said it was fun playing with it. This engine is a old one.. and was ran as a eater for a wile. So I just thought I would play with it....
I have a GP space walker arf that Im going to put a homelite in. but not sure on what mods.. I know I need to have a ch-in in it and not the mag. The fly wheel will not fit. and Im not going to cut a hole in the cowl for the fly wheel lol

Paul

The Raven

Sounds like you're having a lot of fun with it. To smooth the idling you'll most likely need to bring the ignition back a bit, a smaller carb will also help mask that somewhat.

Yes, I'd run a 18x8 prop given those revs. 7000rpm on a Ryobi with that prop flies nicely.

Let us know how your ignition conversion goes, would like to see what's involved. At the moment they are too expensive for me.

fokker38cc

Raven
Good morning Sir
I am reading this post and casually go into your gallery
Wow
I fall in love with your beauty , I am a believer of foam but in Argentina I can take only white foam, I am living in an area outside big cities and it is still dificult take white foam.
I am interested in your beautifull fuselage made of foam.
Details ?Please
Write about fuselage ,F1, sides material and glue , F2 , tank, fuse weight, rudder etc, how to atach motor and square ring outside of F1.
I have a flying wing with a Poulan 25 cc stock ignition and carb throat enlarged by file at 9.5mm, muffler made of a can of mosquito poison
Fly great at 6.1 kg and 1500 sq in of wing area, fuse of lite ply of door skin, bottom and top of balsa , rudder only (remember is flying wing) of balsa covered with monokote and wing of white foam covered with brown paper glued with white glue thinned with water and latex paint.
Fly with autority and provide relaxating flights and have logged more than 30 hours of flying time , both the engine and I were new in conversion engines, only minor incidents, props broken and landing gear bent ocasionally.
Fly like a trainer say my friends.
Many thanks for your time
Happy landings
When I have time I can send photos of my plane
Sorry have no gallery, no camera, no friends with camera and time
Jose
Argentina
South America

The Raven

Hi Fokker38cc,

My plane is based on a design by [link=http://www.flybyphotography.com/CrazyHerb/index.htm]Crazy Herb[/link]. The original design no longer appears on his website but I have a copy [link=http://members.optusnet.com.au/~semac2/]HERE[/link].

The aircraft is constructed using DuPont Foamular 250 extruded polystyrene, which has a load rating of 25psi. It is heavier than white foam but far stronger.

The fuselage started as solid foam with a ply support down each side. The rest of the fuselage was sheeted with balsa, which added some weight.

The wing has two spars, 3mm ply would be just as strong and much lighter than the monster spars I used. The wing is covered in brown paper and paint.

If you build a plane like mine try to keep it light. While my plane flies nicely it is very heavy (15lb/7+Kg). The lighter you make it the better it will fly.

As already mentioned the engine is a Homelite 25cc, which has just been changed to 30cc. All the conversion parts were bought from a local manufacturer. The carburettor is a Walbro WA-167. Do not use the standard carb as it has no high end needle and will run very lean (even after lots of modification).

Forgot to mention I used a flat bottom wing, you can basically make whatever wing shape you want.

A friend also built one of these (see pics under "HERE") and we both found the plane to be tail heavy. I would suggest you add at least 2 inches to the front of the plane, leaving the wing where the plan shows.

fokker38cc

Hi
Nice planes, I know you enjoy the flight
I see your planes in HERE very nice grass, I am living in semidesertic area, my landing strip have big stones and small stones.
Perfect for a cheap plane and the engine have air filter , very good, I am using with it because sand fly with the wind.
My area is windy.
If you send me thru PM your mail I will send pictures of my plane.
I make my own props of wood, because here a prop is 17 U$S, payment of half day at work.
With two hours and 1 U$S of wood I make a prop, and work I measure thrust and it work.
The conversion is addictive I have a McCulloch in the work area, only adaptor to the coil and go to the field for test. I make test with special test stand and a fish scale attached to measure thrust. Cheap and funny.
I am a sunday flyer and like relax and fun, also cheap .
Happy landings
Jose

The Raven

The nice grass you see in some of the pictures is from our new flying field. We had just seeded it and the grass was growing nicely. This summer is very hot and not much rain, now the grass looks a lot browner. Hopefully we can keep it alive over the next few months.

I will send you a PM but you could put them in your RC Universe gallery for everyone to see.

Props are basically the same price here (at least for the large ones) but I am fortunate that I haven't broken one yet (despite three landing which should have broken it).

I tested my 30cc Homelite yesterday but I didn't fly it as there was too much wind. With the standard muffler I could only get 7200rpm, which is well below the 8000rpm with a pitts muffler. I will have to order a pitts muffler and drill out the stock muffler for the moment.