Liberty Engine

retread · 3 November 2002, 04:30 AM

I have been having a little bit of difficulty finding details of just what were the problems associated with the (infamous?) Liberty engine produced in the U.S. during the later stages of the war. Other than the fact it was a large engine and apparently oversized as well as overpowered for many of the airframes.
Were there mechanical problems associated with the engines as well? Also, does anyone know the original designer and/or manufacturer? Apparently this engine was known as a real mankiller. Was it just ahead of the curve or did it have fundamental problems in design and/or manufacture? :-/

Shooter · 3 November 2002, 05:00 AM

I asked a similar question about the Liberty power plant a couple of years ago and the consensus of all was that the biggest problem of the engine was its weight. The knowledge of the Forum today is much more sophisticated, so there might be other problems associated with that mill.

Shooter sends

chip55 · 3 November 2002, 05:20 AM

Hello
Although it don't say if the Liberty engine had faults, there are good articles here:

http://www.oldengine.org/members/diesel/liberty.htm

http://www.centennialofflight.gov/essay/Ev...es/Tech23G4.htm

http://www.uh.edu/engines/epi1309.htm

be well
chip55

chip55 · 3 November 2002, 05:22 AM

Hello
Although it don't say if the Liberty engine had faults, there are good articles here:

http://www.oldengine.org/members/diesel/liberty.htm

http://www.uh.edu/engines/epi1309.htm

be well
chip55

3 November 2002, 11:45 AM

The Wright Pat Museum has a large amount of information on post war modifications. They used to loan their material via mail.
Most of the problems of wartime engines were discovered in post war tests, and if you are interested in results of changing cams, etc, this can be quite enlightening. Many of their documents are from the SAE.

3 November 2002, 01:04 PM

By WWI standards the Liberty 12 was an advanced and sound design, but the engine suffered from a short operating life. The Liberty was expected to have a TBO (time before overhaul) of only 100 hours, which probably made some sense in wartime as aircraft often did not survive very long. But apparently many engines did not manage to run that long. The first parts to fail were the connecting rods and the main bearings.

The Liberty 12 came in high-compression and low-compression versions, with and without various types of reduction gear, and was built by a number of manufacturers; this must have resulted in a lot of variation in reliability.

By peacetime standards the Liberty 12 was considered dangerous and unreliable, so in the late 1920s Allison was given a contract to modernize some (2000 - 3000) of the mass of Liberty engines that were still in stock. By replacing the plain bronze connecting rod bearings by steel-backed lead-bronze bearings, and some other modifications, the time between failures was increased from about 75 hours to 600 - 800 hours, according to Allison.

ONEALM · 3 November 2002, 04:30 PM

Weldboy -

If you really want to see and hear one - get yourself to Rhinebeck next summer. They have a refurbished Liberty on a mobile stand with a big 9'-something propeller on the front.They run it during the Sunday airshows and it actually sounds great. I expected lots of racket and it's suprisingly smooth.

Now all they need is a DH-4 to stick behind it....

Regards,

3 November 2002, 10:40 PM

I guess you mean other than FIRE !!!!

baldeagle · 4 November 2002, 03:55 PM

* * Another place to hear one run is the Historic Aircraft Restoration Museum at Creve Coeur Airport just west of St. Louis, and that one is on the front of a repro DH-4, which should be flying next year. By the way, they also have a LeRhone-powered Sopwith Pup with a working Vickers machine gun that fires blanks, and drops shell casings on the ground as it flies by. Also a Curtiss Canuck.

* * * * * * * * * * * * * * * * * *AK