RCV Update

LAST EDITED ON Apr-27-03 AT 06:02 PM (CDT)
 
Well, for those of you interested in the RCV58CD, you might want to hold off a bit. I like the engine pretty well, but it blew a ring on me yesterday. Couldn't figure out why the rpm suddenly dropped to like 8500 when it had been banging out at about 10,200. A little assessment showed the ring was shot. Now, I don't know if this was just a fluke, or all I can expect out of it with the sort of load we put engines under is 2 or 3 gallons of fuel. But if durability is an issue, then I suspect that this engine will get shelved.

I'll let you know. I'm sending it off the the factory for assessment tomorrow.

Bummer Randy. You're having kinda crappy luck here lately. Didn't you say you set up the nose of the new ride to accomodate a different engine, just in case something like this happened?

Randy, if it helps, I think you're doing the right thing, sending it off to the factory. I have to wonder if the problem isn't from the short piston. It is exceptionally short, and may rock in the bore a lot. Get that Saito .72 in there and re-read GZ's article a time or two. Also confer with PW on props! Good luck, Steve

Steve and Nils,

Well, I'm in the process of fitting in a Saito 56. My Saito, at least, Has more than enough power. I've also learned something today: If you can't get what you want, make it yourself.

In order to fit the Saito into the new plane, I needed a shaft extension. Since the Saito has that stinking 7mm crankshaft, this isn't available. So, after studying the problem a bit, I bored out a Fox 3/4" shaft extension a bit and made a new nut. I made it from aluminum as a trial. Took 2 trys to get the procedure down. Now, I'll hunt down some 5/8" steel dowel tomorrow and make one from steel. I suspect the aluminum unit wouldn't hold together long. It was just done as a trial.

So, the engine is ready, Now I just have to machine out some new motor mounts (Be darned if I can find the other pair I made for this plane) and fit the engine up. Take some hogging on the inside of the cowl to fit over the camshaft cover, but that's about it. Oh, I will have to punch in another hole for the needle valve...sigh. I misjudged the difference in engine length so the needle is about a 1/4" ahead of the RCV. That's life.

I hope the RCV turns out to have some strange problem that can be fixed, but I'm not holding my breath. It shows a lot of promise. Has a bit more torque than the Saito (or it did) and has some other advantages that I really liked. But it is about an ounce heavier...Hey!, I can take some of that weight out of the tail.

LAST EDITED ON Jun-27-03 AT 01:05 AM (CDT)
 
Just a note. The Dirt pointed out to me that I never told anyone how this all came out.

I got the RCV back and they did some interesting things to it. It's got a different piston than the original had and some odd looking bearing on the rotating cylinder (ceramic?). I've got about 40oz of fuel run through it, gradually bring the rpm up and stated in the break in directions. Ran it full bore with venturi for the first time tonight.

It runs just about how it did when I originally broke in the first one (did I mention that this is not my original engine, but a new one?). With the Eather 12.5x4.5 3 blade prop, just sits at about 10,200 rpm, humming along. I'll run it a few more times on the bench to be sure I've got it sufficiently broken in and bolt it back in the plane. Hope it flies like it did originally.

Randy
I did the same thing you are doing on making a shaft extension for a Saito 50 and had problems kicking the prop loose. Maybe you could pin it.
Willis

Willis,

Oh, I fixed the problem with the shaft extension. I made another, slightly longer steel nut that allowed a bit more torque. Problem solved.

I'm eagerly waiting to hear that RCV running, Randy. How about Arlington on the 12th? Air show, D-bat Training, CL demo's (usual field), and over on the East side of Arlington Airport, Cascade Aviation (Paul Vallins) will have BBQ'd burgers going all day, free. Will there be any Lancairs present? Steve

LAST EDITED ON Jun-29-03 AT 11:59 PM (CDT)
 
Interesting. I'm in the middle of a book about the Rolls Royce Crecy, the ultimate in reciprocating internal combustion engines. About the same displacement as the Merlin, it was supposed to put out something like 4000+ horsepower. 35% of this power was supposed to be recovered from the exhaust, either from direct thrust, or through the use of a turbine geared to the crankshaft. The engine was (get this) a sleeve-valved, 2 stroke V-12. Work on it stopped in December 1945, since the war was over and jets were flying.

What was interesting was how the sleeve valve worked. I always thought the sleeve rotated (like on the RCV engine). This one moved up and down, as well as side to side (sort of like an orbital sander). This allowed the exhaust ports to ring the cylinder completely.

The other interesting thing was that, at 3000 rpm, you had 36,000 exhaust impulses a minute. These things probably sounded like Carl Dodge's F2A Speed models, just a heckuva lot louder. Too bad few have had a chance to hear them.