my 2-stroke 0.46 glow "Big Fat Wolf" project

[Antti]

Hi everyone. I just found this site and decided to register and tell whats going on. Here is a tale of my own making of model aircraft glow engine:

One evening when I was reading a catalog, I found some model engine plans. When I came back home, I started to find some from the web. Finally, I found a simple two stroke glow engine plan by Shane Wighton. First I had to convert the inches to metric in order to understand the size. When that was done, I found out that the engine will be way too small for my planes. So I doubled the measures. The next problem was the materials used: a lot of steel and a bit of aluminium -> too heavy . I also had to make some own design in order to make this engine proper to be mounted to aircraft. Although this engine is based on Shane Wighton's 2-stroke and a couple of things are copied from SC 40, I've made also a lot of own designwork.

At this moment, the engine is about half-ready. Crankshaft is almost ready, crank-case almost ready, cylinder almost ready, cylinder head is ready. The only things I haven't started to make are: crankcase-cover, piston, con-rod, rotary valve and intake manifold. So there is some work to do and not much time before summer (I'm making this at Nivala vocational school while studying machinery). Since this is my first engine this is not 100% homebuilt, but not far from that. the only parts I'm not going to make myself are carburator, crankshaft bearings, muffler and glow plug. Of course I could make this 100% myself but I just have not time so I make muffler and maybe the carb later.

And what are the machines used to do this? Everything between sandpaper and 5-axis cnc-mill But mostly I'm using manual lathe and manual mill

The name "Big Fat Wolf" comes from the size of this engine and mistakes while making this. "Big" because the size of this engine is approx. same as 110 four-stroke but the capacity is only 46 "Fat" because this has got a plenty of metal and weight, at least this feels heavy and "Wolf" because in Finland we call something broken, bad, improper etc wolf. I had to re-do almost all of the aluminium parts because of some mistakes so I made some wolves ;D

Of course you want to see some pics so here I have some and more coming soon: http://kuvablogi.com/blog/27523/1/
If interested, I might publish the plans of this engine if I found this engine working

 

[rake60]

Welcome to HMEM Antti.

Nice progress on your engine! Thm:

Rick

 

[itowbig]

were always interest in plans yup yup yup. nice engine

 

[Maryak]

Antii,

Welcome to our forum. wEc1

Best Regards
Bob

 

[Antti]

thank you guys nice to get some interestment from more experienced people. I've got a feeling that this engine might be too heavy and underpowered for aircraft use but we'll see...

here is a link to the shane's engine: http://www.john-tom.com/MyPlans/SteamPlans3/Shane2Stroke/Shanes_Two_Stroke_IC_Engine.pdf

this project has taken a lot of time but most of that time has spent while thinking and planning. this would be ready if i had already good instructions but that would be too easy?

I have one problem with this: where I can find some cast iron to make the piston? I was told that cast iron would be the best choise and it prevents engine seizure but cast iron might be difficult to find. Could I use any other materials? the liner (you know the pipe inside cylinder where the piston moves is that called liner?) is made of steel and I'm going to use cast iron or aluminium from old pistons to make a piston. Or could I use any other metals? And what about bronze cylinder and aluminium or steel piston?

 

[kf2qd]

you might take a look at the .60 plans i uploaded to the forum. Aluminum, cast iron sleeve and steel crank. And material that could be machied off to lih=ghten it up, but most planes i've built needed some ballast anyways... The cad files are there also so you could scale them and then redo the dimensions and have it in metric. Made from 2" (50mm) square bar.

 

[Antti]

thanks i'll check it out your engine looks a bit same as mine

 

[kf2qd]

Hey - A 2-stroke is a 2-Stroke. May pretty a part here or there but they still work on the same principle. Some are designed to compensate for some requirement of materials or apendages but they are still the same basic parts put together in the same basic way.

And what really great is they RUN.

 

[Antti]

today i made some progress, not much but progress anyway in a couple of hours. finished the rotary valve and crank and started to make the conrod. I also looked for cast iron and I found some about 80mm cast-iron bars, but they are too thick and there is no sense to make piston of that (but i might make some moped cylinder sleeves 8)).

so plan b: piston made of aluminium. at first i planned to make it of pure aluminium, but then i realized that pure aluminium piston will be too weak. so i decided to melt some moped pistons and use it. i asked about it and i was told that made-in-vocationalschool foundry cannot produce good enough quality I also visited local "blacksmith" but he didnt have any cast iron.

so plan c: steel sleeve and hardened steel piston. i could also make bronze sleeve or piston but i dont have much bronze bar left and i want to make some bronze jewels for my girl

tomorrow i have maybe seven hours so i try to get conrod ready and maybe the piston too. new pics coming soon

 

[Antti]

now i have made the crank, conrod and piston. the crank needs to be balanced and the piston needs to be finished.
the deadline of this project will be june 4th when the summerholiday begins and i wont be able to machine for two months

pic of crank, conrod and rotary valve: http://kuvablogi.com/nayta/2611145/

 

[Antti]

i've made some progress again. the engine needs only gaskets, bolts and one nylon part to the crank and then it's ready for assembly and the first start unfortunafely i have a bad feeling about the rotary valve. i think it wont be tight enough for smooth running but we will see... and of course i will post a video of the first start

i've been thinking about my next project. twin-cylinder glow or maybe a stirling for rc-boat use. any suggestions?

 

[Antti]

today i finally got this engine ready to start. it didnt start but i saw some flames and smoke coming out from exhaust port. so not bad for the first engine. what went wrong? not enough compression or bad fuel? the fuel was about 2-3 year old and contains (or used to contained) 10% nitro. i started O.S 46LA with that fuel yesterday. i also have fuel which contains 20% nitro so i try to get it running with that.

 

[Antti]

today i tried to start this again, this time with methanol&20% nitro. nothing happened. then i mixed some gasoline with methanol and then it got some life but didnt start (and my glow plug battery died). tomorrow i will charge the battery and try to start this with hotter glow plug. and if nothing happens, i will lower the cylinder 0.4mm to get more compression.

I ask you again: what engine i should make after this one? stirling? multi-cylinder glow? steam? wankel?

 

[Antti]

hi there! havent got much time to work on this. luckily my summerjob ends next friday. i found the reason why this one didn't start: too big combustion chamber -> not enough compression. cylinder head and cylinder sleeve has been turned so now there should be enough compression to ignite the fuel. if this one starts, it wont probably run nicely untill i fix the rotary valve. there is a leak but i think i can fix it.

but guys, seriously, any opinions about my next project? it could be 100% myself-design twin-cylinder stirling engine or Lobo Pup 1.6cc twin diesel. i'm really interested in diesel engines and lobo pup would look nice next to my big fat wolf on bookshelf but it would be much easier to get a diesel engine if i just modify wolf's cylinder head. i have two heads for wolf: one good and another good with bad glow-plug threads. the worse one would be good for diesel use if i just add the compression adjustmen screw