JN4D and the Liberty engine

Dear all.In The Canvas Falcons book there are some strong criticisms of both the "jenny" and the liberty engine.How much truth is there or is it just bias? Can the Liberty lump be as unreliable as said (in the book).The report is that it was prone to cutting out at inapprobiate moments!Was this a desiegn or manufacturing defect.Regards andy the tyke

[leo]

I have read that the problems with the Liberty 12 had to do with the automotive type ignition the engine had. Once the system was better understood, the engine proved to be reliable.

leo

There was an oil consumption problem early on, but this was controlled by a redesigned lubricant. It received bad press from writers that had no knowledge on the subject of aircraft engines.

Regards,
SteveD

There were several changes made to the Liberty over the course of time. And we must remember that parts for these engines were for the most part hand made. Much as with German/British/French planes and parts, parts and assemblies built at one plant didn't always fit well with engines made in other plants. Problems that could only be discovered in actual use were delt with as expidient as was possible for the time. Needless to say, the Libertyof 1920/21 was not neccessarily the Liberty that rolled off the lines in mid 1918. Bare in mind as well that the Liberty also was produced in, if I remember corectly, 3 different horse powers by the end of the war.(Don't quote me on that - I may be wrong.)
As for the Jenny, which Arch Whitehouse called a "trans-atlantic horror", it's chief fault was the one that made it such a good trainer aircraft, and that was that it was inherently stable. Pilots trained on the Jenny, which one had to almost force into a spin, killed themselves at an alarming rate when turned loose on real front line aircraft which by design are inherently UN stable. Most of the American pilots who were shipped to England for training by the British (the so called 'Oxford Boys') were forced to re-do all that they had done at the Texas airfields on Jennys, all over again, but on Avro 504's which were a 'step up' so to speak. This was done in an effort to prevent killing off the fledgling aviators. Hope some of this helps!

The Jenny was actually a superb ab initio trainer; if it had a flaw, it was that its top speed was only about 75 mph. Stability is not a curse in a basic trainer.

If you want a graphic demo of the Jenny's usefulness, compare training casualty figures in 1916-17 for RFC training squadrons in Canada -- which used the Jenny -- and in the UK -- which used such horrifically unsuitable types as the Farman MF. 11. (I don't have the exact figures here, but there's a piece on RFC training on this site -- ahem -- that provides the data.)

[leo]

Wern't the early Jennies wing warpers? The pilot wore a harness which he used to warp the wings during turns?

leo

Dear all. Thanks for all your help. Safe flying.andy the tyke