Question about the RR-1 Valve

Cribbs74 wrote:I think it may be where the inlet opening resides and not the pin.

Yes, but changing the location of the pin effectively changes the opening, no? It would be the same result. So logically if I made a copy, cut the opening, and then drilled the hole accordingly, reverse rotation?

You are correct about moving the pin. It's the same, don't know what I was thinking! Perhaps I wasn't thinking...

Cribbs74 wrote:You are correct about moving the pin. It's the same, don't know what I was thinking! Perhaps I wasn't thinking...

Don't worry. I had to think on it more than a few times to figure it out. I've been thinking on it all day though. Now next question, since it's not really balanced, couldn't I just drill a hole in this one? And make it adjustable? I'm not saying I will, but if I do make another, I could just do the same to it and I'd be able to run any rotation I want with one piece. Correct?

We need Mudhen. He'll probably see this thread. The valve opening probably needs a shift of a certain number of degrees, which I can't fathom a guess at without taking mine apart, something I'd prefer not to do unless no answers arrive. If you had a left hand Tee Dee crank to compare to a RH crank, you could probably get a good idea of how much the timing shift is.

Lol, I was looking online for a pic of a reverse TD crank to compare. Maybe Jason will see this and post pictures. It probably is real easy. I wouldn't modify the original part though.

Cribbs74 wrote:Lol, I was looking online for a pic of a reverse TD crank to compare. Maybe Jason will see this and post pictures. It probably is real easy. I wouldn't modify the original part though.

That's what I was saying. I wouldn't modify the original. But more trying to create a visual. Of having two holes in one piece.

Yes, that should do it. The Cox engine is a directly in-line configured engine, the crank is not offset from the bore to favor one direction over the other. If you exactly mirror the hole with relation to the opening then it should perform exactly in reverse.

If I was making the new parts I would position two holes.

Alternately if you rotate the tank 90 degrees you should achieve reverse rotation of the engine...

Phil

pkrankow wrote:Yes, that should do it.  The Cox engine is a directly in-line configured engine, the crank is not offset from the bore to favor one direction over the other.  If you exactly mirror the hole with relation to the opening then it should perform exactly in reverse.  

If I was making the new parts I would position two holes.

Alternately if you rotate the tank 90 degrees you should achieve reverse rotation of the engine...

Phil

I knew about the 90 degree trick. I was looking for a small project to do at school. I'm in school to become a machinist and have been practicing on the lathe and mill extensively lately. And thought this would be a great project. It seems pretty straight forward. Turn down the bar stock to the widest part of the valve. Measure the thinnest parts depth. Turn that down. Drill the center with an appropriate drill and to the proper depth. Cut off the part at this point at the thickness of the widest part. Then head over to the mill, measure and drill the pin holes and use a woodruff cutter to cut the slot.

Well, for a class it is definitely worth it! Low material cost + good grade = win for everybody!

Phil

Might be worth it to make a couple, regular and reverse. I had one break on me.

Cribbs74 wrote:Might be worth it to make a couple, regular and reverse. I had one break on me.

I didn't know the valve was a weak point. I've been reluctant to run mine because I'm worried about the crank pin. But I guess that's the risk of having a desirable engine. Although, the crank may be my next attempt at a part if this goes well. Maybe I'll start making replacement RR-1 parts so we can run them and be a little more at ease. 

I am not sure if they are inherently weak as it's only happened once to me. Rusty flogged his without any issues so who knows.

Ron

yep, it's 90 degrees the other way, the original LH rotary valves were coated in black oxide to help id them.

Mark Boesen wrote:yep, it's 90 degrees the other way, the original LH rotary valves were coated in black oxide to help id them.

And there we have it. Mark, you da man!

Rusty

G.O. Stang wrote:

Cribbs74 wrote:Might be worth it to make a couple, regular and reverse. I had one break on me.

I didn't know the valve was a weak point. I've been reluctant to run mine because I'm worried about the crank pin. But I guess that's the risk of having a desirable engine. Although, the crank may be my next attempt at a part if this goes well. Maybe I'll start making replacement RR-1 parts so we can run them and be a little more at ease. 

Does the RR-1 use a different crankshaft than the regular cox engines? I have a VGE Rotary Valve engine, and it appears he used a regular crankshaft. Thanks, Andy

I would double drill the replacement valves just to confuse everybody and make it apparent they are a reproduction. It also makes for options in setup.

Phil

COOL JOB maybe this could lead to some of those prop collars I read about, seems I am running into props that have been reamed and want fit 049 s small diameter prop screws , don't no what they were putting them on before ? 

APC props need a collar, the outer hole is held to tight tolerance, but the inner hole is not. Since it is a universal scheme for electric power I expect to see more of it from other brands.

Phil

anm2 wrote:

G.O. Stang wrote:

Cribbs74 wrote:Might be worth it to make a couple, regular and reverse. I had one break on me.

I didn't know the valve was a weak point. I've been reluctant to run mine because I'm worried about the crank pin. But I guess that's the risk of having a desirable engine. Although, the crank may be my next attempt at a part if this goes well. Maybe I'll start making replacement RR-1 parts so we can run them and be a little more at ease. 

Does the RR-1 use a different crankshaft than the regular cox engines?  I have a VGE Rotary Valve engine, and it appears he used a regular crankshaft.  Thanks,  Andy

It's used a regular babe bee type crank, however, there is a small pin on the end of the larger pin and it is specific to the RR-1. Can be seen here.


Look closely. The smaller pin drives the rotor valve.

I have suspect a pin can be pressed into the hollow diesel crankshaft pin with relative ease to make a RR type crank.

OR the pin can go on the valve and fit into the hole in the crank.

Phil

pkrankow wrote:I have suspect a pin can be pressed into the hollow diesel crankshaft pin with relative ease to make a RR type crank.

OR the pin can go on the valve and fit into the hole in the crank.

Phil

I've thought about this. It would work and be fairly strong to press a pin into the hd crank. However, this would degrade the strength of the pin since it would no longer be hollow, and the press would need to be enough to hold the smaller pin in under the vibrations and I would be afraid to stretch the larger pin with too much press. The pin on the valve I would think would be too thin and sheer off since it would have to be thin enough to fit in the crank pin hole and precise enough not to bind up. The best method would be the factory solid pin design. I may experiment with the hd crank though. As I think about it, pressing a small pin in may not be such a bad idea. But my main goal is to produce an RR-1 direct replacement. So that if mine breaks, I have one I can just swap it.

Unlike most, I deliver. Here's the progress on the valve.

Here you see my RR-1 half disassembled. There are 3 vales in this picture, one on the tank, my muse/spare, and the shiny new one.


The project next to the muse.


Note, no slot or crank pin hole have been cut. I only used the lathe today. The milling will be tomorrow.


She fits perfectly. All measurements are identical to the stock part within .0001.



Tomorrow hopefully we'll have a finished part.

Side note, this piece is aluminum where the factory part is steel. I weighed both parts and my aluminum part is heavier. So I figure they will weight very similarly once the part is done. And aluminum is much easier and nicer to machine.

Very nice.

Phil