6 Cyl Radial Air Eng (GrabCad)

[Jmccrack]

Has anyone seen an air valve system like the one on this engine?

 

[nparmley]

I've looked at the design on Grabcad, and can not see the cam system. If you cold post the the cam system with a view of the piston/pistons maybe someone could figure out the timing. I suspect you have built an engine someone made as a cad exercise without considering actually making it a working design. My 2 cents.

 

[nparmley]

Please, pay no attention to my previous post. I was looking at the wrong engine. Finely, found the correct one, and will try to look at the time.

 

[Jmccrack]

Thank you so much for your interest. I could sure use the help. And it is a GrabCad engine that probably has never been built.

 

[Jmccrack]

Sorry guys this thread somehow got moved (my bad). The pictures and drawings are on a different thread

 

[Steamchick]

Thanks Gary: "I.C. radials fire every other cylinder "... So for a 7 cylinder 4 stroke, it would be timed (cams and ignition) for 1,3,5,7,2,4,6 ..??
Thanks!
K2

 

[kf2qd]

Good day,
I am not familiar to the type of engine you have built. Aircraft radial engines use an odd number of cylinders in each row.
Single row use 7 or 9. Twin row 2 x 7 or 2 x 9 etc.
Your con rod arrangement may be out of whack. I will chase up a picture and post it.
50+ years since I completed my apprenticeship.
I hope this helps and I have not confused the whole thing.
Regards, Dennis

A radial or Rotary gas engine has an odd number of cylinders because they fire everyother rotation and the sequrnce goes 1-3-5-2-4 and back to 1 for a 5 cyl. And air engine does not fire so it can drive on every revolution

 

[adolfgalland]

KF2QD just said it perfectly. The original question asked on this discussion was about a air powered radial and it turned into discussing both air and gas powered. I have never seen a 4 stroke air powered radial so yes they fire one cylinder after the next and you can have any number of cylinders you want. I have thought about trying to build a 4 stroke air powered version for several years but just haven't put the time or effort into the design stage. Would be interesting to hear one run. Gary

 

[Peter Twissell]

I'm not sure why one might consider a 4 stroke air engine.
There are only two phases to an air engines operation, power stroke, with air pressure admitted to the cylinder and exhaust stroke, with the cylinder open to atmosphere.
Would a four stroke air engine have compression and expansion strokes?
It seems like it would simply reduce power and efficiency.

 

[adolfgalland]

You are right Peter that 4 stroke air powered engines could be considered a bad approach to what is practical and efficient. The only reason to do it is for the true 4 stroke sound. A highly respected gentleman named Chuck Fellows pioneered the 4 stroke concept with air power with a unique ball and spring arrangement. I have used it and went a step further and put a true 2 valve system in the head of engines like my version of Chuck's John Deere styled engine shown below. Naturally there is no compression in these engines but the sound is very nice.
Gary