Back in the mid-90's Frank Anderson asked me to take some pictures of a Drone .40 diesel.

I ran across this leftover shot of the .40 with a .29,

From what I remember, Leon built two of these engines and one was campaigned by Hal DeBolt in a UC Stunt Model.

I think a .49 and not a .40 Jack

I was told it was a 40 but who knows? I know a McCoy 49 was a lot thicker than a .29 so from comparing the two Drones they looked fairly close. It did have a long stroke so maybe that's where the displacement gain was made.

Perhaps some Drone experts who knew Leon or Hal might have some details.

Text from the article The Drone Story.

Thanks for that, I thought a .40 was not a typical displacement for that period.

my only other question was the number made. I was told there were two, one campaigned by Hal DeBolt and the other one was kept by Leon. My picture is of Leon's engine, I don't know for sure if another one exists.

My intention was to show this engine existed.

I have a couple of the Drone .29 ball bearing versions. This one with an Aerodyne variable compression head. Jack

Here is one with the stock head. Jack