quote:

ORIGINAL: Patxipt
Sadly, Mr Turner deosn't mention how he managed to seal the threads - The only way I found was using plumbers teflon tape and that only worked on the small thread size of the M5 screw used on the 12A. Maybe he got lucky, maybe he knows better than me

quote:

ORIGINAL: AMB
Just a guess the O rings life may be shortened by the thin edge of the threads vs a sold contra with its grove
as it is moved in or out martin

I just found this thread.

I didn't eliminate gas leakage past the M10 x .75 thread...but it wasn't horrendous and didn't seem to pose any detriment to the engine's running. More "hillbilly engineering", I guess. The whole project was an experiment, knocked up with the minimum effort.

 If I wanted to do a better job, I'd simply shave a midgin from the standard cylinder head...you may recall that the engine will run well using its standard head, provided that you energise the glow plug to assist in starting. A small increase in compression, over the as-bought standard, would be useful. That would solve any potential problems with blow-past. But, of course, you are left with a fixed-compression diesel and so a very limited propeller' choice.

Meanwhile, I fancy taking a crack at a four-stroke. That Enya is just beautiful. Here's a bit of video of the Enya in action. I do have some of the ST.75 in action too, if you are interested.

http://www.youtube.com/watch?v=56TlDkyqErU

David Turner

http://www.youtube.com/watch?v=hhOm2TL72t4 

A rough old model, which I cadged from a pal, fitted with the ST .75 diesel...just to prove that it works!

Actually, I've been pondering diesel issues for some time. What do you think about using a diesel engine, running at a steady speed, in conjunction with a Constant Speed Unit?

With available off-the-shelf technology, I reckon that this wouldn't be too difficult to achieve. Any thoughts?

quote:

ORIGINAL: bogbeagle

Actually, I've been pondering diesel issues for some time. What do you think about using a diesel engine, running at a steady speed, in conjunction with a Constant Speed Unit?

Very nice, Patxipt...I'd like to see the airframe you put that in.

Gkamysz, AFAICS, one of the major drawbacks of diesels is the problem of operating over a wide speed range (I mean our model diesels, which have no fuel injection).

If I could run the engine at fairly constant RPM, but vary the load via the medium of controllable pitch, I could get around the need for contra-pistons, but still have a practical power unit for model aircraft.

The engineering should be fairly simple (says he, having never actually tried it!). I just need to get around to making it happen.

quote:

ORIGINAL: bogbeagle

Gkamysz, AFAICS, one of the major drawbacks of diesels is the problem of operating over a wide speed range (I mean our model diesels, which have no fuel injection).

Have you guys been having trouble with the Enya 40 diesels, then?

The one which I have been flying (in the Ready 2) belongs to my friend. We've both been using it, from new. Since that time, I have accumulated a little over two flying hours with the model. I'm not sure how much time he has spent flying the plane; probably a similar amount. When we first acquired the engine, we had a bit of fun. What we'd do is to flick-start the model (making sure that there was an audience) and leave it plopping along at idle whilst we wandered off and sat down...and waited...and waited.

Several people were completely taken in by the fact that we had started our "glow" engine without the aid of a glow-driver; and they were quite ready to believe that we had, indeed, devised a self-igniting glow plug. They would be even more amazed when, after a very sustained idle, the engine would pick up and be ready for flight. Of course, these guys were unfamiliar with the smell of diesel fuel, and so were ripe for comic exploitation. They'd be salivating at the prospect of buying one of our special glow plugs, at the knock-down price of just £28.

Anyway, during its time with us, that little Enya has never quit; save for when we've run the tank dry. A .70-sized engine would be great, but I don't believe that they have any plans to make one.

The Laser diesels are really difficult to find. I tried to source one  a while back, but the only one that I could find was just too expensive. I contacted the man, Mr Tidey, but he told me that he has no diesels, no spares and no plans to re-introduce these products. Were the Laser diesels any good? I dunno.

Re Enya prop and compression. I will come back to you with this information asap. As I say, the motor belongs to my pal. So, I don't have it in front of me so that I can take a look at the prop. I'll email him right now.

OK, my pal says that when he received the engine, it was partially disassembled. He fitted a single shim to the cylinder head...shim as supplied by Enya.

I recall that we bored out the dummy glow-plug, so as to reduce the compression a bit further.

Prop is a 12 x 5.

Commercial diesel brew.

Works very well. Only slight niggle is a little hesitation following a prolonged idle. We think that this results from the engine becoming chilled.