Has anyone built the Jan Ridder Bobber?

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I am getting started building Jan Ridder's stirling Bobber engine. Yes, it is probably not the best engine to start out on, but one benifit of being dumb is not knowing when you are in over your head.

I was wondering if any members here have built or have experience with this engine design? There are some parts of the drawing they are making me ??? ??? ??? Mr. Ridder was very nice in sending me the drawings, but I hate to bother him with a bunch of newbie type questions.

Can't get it thru my thick skull on how the cylinder and cylinder end are to mesh up, once I get home this evening I will post a image of the "problem area". Thanks
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Here is an image of the parts that have me baffled. The cylinder body has a 10mm diameter bore, the cylinder head has a 12mm diameter protrusion. The body and head are to bolt together flush, but I see no way for this to happen, other than to force fit the 12mm dia into the 10mm bore.

The sectional view shows what looks like a slight counter bore in the body for the 12mm dia to set into. However I have studied the drawings and see no counter bore called out. All I can figure is it must be:

A. I am reading the prints wrong. I have a degree in drafting so I think I am reading the print correctly, but I can be very thick headed at times and over look the most obvious things.

B. The two parts are "force fitted" together to make an air tight seal. I am new to sterling type engines, but the force fit idea seems odd to me. I don't think that is the answer

C. There is an omission in the drawings, and a counter bore should be called out. I hesitate to say that, as I don't want to be one of those people that immediately blames others.

Anybody have any ideas, thoughts, suggestions? I searched the archive and didn't find any posts relating to this engine design, however I did see where Mr. Ridders signed up to be a member. My best bet maybe to email a link to this thread to him and see if he has time to reply...

 

[stevehuckss396]

I think you are correct about the 12mm counterbore in the cylinder. Things like that happen and sometimes you have to use good judgement. Welcome to the wonderful world of model engines!


I think you are wrong about not contacting him. Worst that can happen is he point out where you missed it on the plans. Best case is you can point out where he missed it on the plans and the correction is made for future builders.

 

[rleete]

Counterbore is 13mm, from what I see. Clearance of .5mm diameter. Depth of CB is not called out, but anything slightly over 1mm should work.

Not the way I would have drawn it (it's slightly confusing), but that's the way I read it.

 

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Counterbore is 13mm, from what I see. Clearance of .5mm diameter. Depth of CB is not called out, but anything slightly over 1mm should work.

Not the way I would have drawn it (it's slightly confusing), but that's the way I read it.

From looking at the drawing it appears that the 13mm diameter is for the 8mm long protrusion on the other end of the cylinder body. The hidden lines in the side view of the cylinder doesn't show a counter bore. However I agree with you that most likely a 13mm counter at slightly over 1mm deep is needed. ???

I sent an email to Mr. Ridders so hopefully he will have time to reply and we can get the definite answer. I plan on starting the base tomorrow evening, the cylinder is a few days down the road. Just thought I had better get the answer now, rather than waiting till the last minute...