Hi, Jim.
In the near future, I will be building a Little Mo.
As you know, it's not little at all.
The two biggest spark engines I have are brand new Orwick 65 and brand new Anderson Spitfire.
Which one would you consider for the Mo?
I will of course run spark ignition with a gasoline/castor/synthetic fuel.
Bob Z.
ps - I also have a Forster  99 - used but runs beautifully!

A couple of other things. I used the angled mounting tabs that bolt to the engine bolts to mount my Orwick. If you have those they work well with one little minor fix. The case bolts are 5-40. Floyd Carter gave me the idea to ream them out to 6-32, and use elastic lock nuts on the rear. It worked fine for me. Otherwise, you can bolt it to the firewall.

  The green one appears to be a late model Orwick 65. The other is a Cunnigham Blue Streak. Cunningham contracted to Orwick in his early engine production, but later they had a falling out as He did not believe Cunningham was finishing the parts like he was supposed to.

  If you take the back plate off of your Orwick the first thing you will notice is the rod is polished to a mirror. The pistons are made from nickel cast combo.

  Orwick welded the pin bosses in the piston to keep them light. They are a work of art. From what I have heard Floyd Carter has them both also, and as far as I know they both run about the same. RJL still produces the Cunnigham blue streak, and I have not looked lately but I believe some if not all the parts are interchangeable.

 What is the serial number on the back plate of your Orwick? I can tell you about when it was made and the slight differences there are in them.

  All of the 9 fin Orwicks were made and assembled by Orwick Himself.

  I would say any of the three, the Orwick, the Cunningham blue streak, or the Anderson Spitfire would be great. They are all well made powerful engines that seem to run forever. The power between the three would be negligible. I love them all.

  Hi Bob. Yes, those are both good repro engines. I am guessing by the pictures that the Orwick is a Brit built Orwick by Dunham. All the reproductions that I know of are very good. K&M built quite a few, but they were all the 11 fin engines.

Dunham also reproduced the 74 which was Orwicks early engine. But they were 10 fin.

  Yours really looks like an Orwick built engine from the details, but the R makes it a repro. Odd though, As far as I know the K&M repro's had the R and 5 numbers but were the 11 fin version.

  Either way, they are all Good.