ABC Dragonfly

[Kosh]

The ABC Dragobfly was really a dreadful engine. One of its bad faults was that at certain RPM it ran on the natural frequency of the crankshaft resulting broken shafts in few hours of running.

As for the word reciprocating, as long as the piston goes to and fro it is a reciprocating engine, be it radial, rotary, inline or what (even steam). I would urge you to read Bill Gunston¨s "The Development of the Piston Aero Engine" (or so). It is an excellent introduction to the subject.

And furthermore, I´d recommend joining Aircraft Engine Historical Society at www.enginehistory.org to have a subscription to their excellent house journal, Torque Meter.

Jukka

[Lufbery]

Jukka,

Thanks for the info on the Dragonfly engine and the pointers to additional information.

Does the Gunston book cover the Dragonfly at all?

Regards,

[stephen]

Merci. I kept reading that the Dragonfly was a dud and ruined any plane that used it, but I couldn't figure why.

[DJ]

In addition, During it's qualification trials, the jugs were known to glow a dull red from overheating.

[Kosh]

Drew, there is (IIRC) some data on the Dragonfly in Gunston´s book. I am also inclined to remember that Gunston biography of Sir Albert Hubert Roy Fedden (Roy Fedden for short) has some info as well. That bio was recently reprinted by RRHT.

Jukka