Elmer's no11 Radial

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lensman57

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Hi and my best wishes for Xmas and New year to everyone,

I have now finished the construction of Elmer's no1 Radial engine.
It does work but not very well, I suspect the valve arrangement is not optimised as yet. There is a constant flow of high pressure air from the exhaust vent at the front. I am still not clear as how the rotary valve works as the design allows it to rotate about the 1/16" pin that drives it or am I supposed have fixed it to the drive pin some how? Elmer's construction notes are not very clear to me.
Many thanks and regards,

A.G
 

lensman57

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I had the same problem with my #11. Read thru the whole build log posts here to see what the problems and fixes were. Runs great now with help from the forum.
http://www.homemodelenginemachinist.com/f31/two-engines-one-elmer-gets-makeover-18142/index2.html
Hi Stan,

Many thanks for your reply, I have read your build log many times and decided to redo the crank shaft as the there is a bit of run out as you had and the rotation is not concentric. My concern is more to do with the oscillating valve. If I locktite the pin to the central hole it will prevent it from rotating about itself, but I am not sure if this is something I should do or not. What does prevent the valve from from rotating about its axis otherwise?
Also I think there is a typo in Elmer's plans on page 46, it states to drill 23 tap 3/16 40- 2 holes, as far as I can see there is only one hole in the valve chamber for air intake.

Regards,

A.G
 

Sshire

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Hi Stan,

Many thanks for your reply, I have read your build log many times and decided to redo the crank shaft as the there is a bit of run out as you had and the rotation is not concentric. My concern is more to do with the oscillating valve. If I locktite the pin to the central hole it will prevent it from rotating about itself, but I am not sure if this is something I should do or not. What does prevent the valve from from rotating about its axis otherwise?
Also I think there is a typo in Elmer's plans on page 46, it states to drill 23 tap 3/16 40- 2 holes, as far as I can see there is only one hole in the valve chamber for air intake.

Regards,

A.G
I just looked at the drawings again.
Correct on the valve housing. As far as I can see on my #11, there is only 1 3/16-40 hole. Not 2.
Since the valve is symmetrical and is turning on an offset valve crank pin, it needs to move freely about the offset axis. Don't Loctite.
I think it's most critical to have just enough clearance between the valve face and the valve housing to allow the valve to rotate and no more. I had a piece of 400 or 600 grit paper on the surface plate and kept sanding the housing until there was slight binding of the valve. Then I did a few sanding strokes on the valve until it just moved freely.
 

lensman57

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Hi Stan,

Many thanks for your tips, I have now got the crank to go around smoothely and it is a better fit in the bronze bushings. Will lap the air chamber next to bring it to touch with the valve. I connected it to my dimunitive air compressor and it does go around a few times before the air pressure , volume drops off, without a flywheel so there is hope for this engine.

Regards and best wishes,

A.G
 

kf2qd

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The valve face and the valve body face need to be very smooth, lapped if possible. And then just a film of oil. Ideally the supply pressure should help the seal, if the contacting surfaces are flat.
 

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