Radial engine main bearings
Radial engine main bearings
(OP)
How was the lubrication feed done for aircraft radial engine main bearings? For a vee-engine the top main bearing shell has a 180 deg groove which flows oil into (usually) two holes drilled into the crankshaft main journal, and then feed up to the crankpins to lubricate the rod bearings. The bottom shell is left plain (no grooves) so as to have maximum load bearing capability since the mains in a vee engine are loaded higher in the downward direction. What oil groove strategy for main bearings was used for (2x)R-9 and (4X)R-9 radial engines such as the Pratt & Whitney R-2800 and 4360? Since there are combustion forces acting all around what solution was used? Any pictures on the internet would be nice.





RE: Radial engine main bearings
http:
The main bearings were roller bearings.
B.E.
RE: Radial engine main bearings
Here's a link to a master/slave rod assy:
http://
Here's an R-2800 crankshaft specific link:
ht
Plain silver/lead bearings on this one.
RE: Radial engine main bearings
Yes, that's a master con-rod type R-9 with a multi-piece crankshaft to enable use of a single-piece master rod. I still can't see the main bearings and what oiling/bearing design was used.
RE: Radial engine main bearings
The Pratt 4360 used a one-piece crank with journal type rod and main bearings. If you get a copy of Graham White's excellent book on the R-4360, there is a detailed lube circuit diagram shown on p.100.
Or take a look here: http://
Good luck.
Terry
RE: Radial engine main bearings
And it actually worked. I saw a motorized cutaway in a museum several years ago and spent an embarrassing amount of time just following the motion.
Beautiful.
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Radial engine main bearings
move along, nothing to see here
RE: Radial engine main bearings
The 4360 does appear outwardly complex. But the basic engine configuration is "simple". It uses 2 valves per cylinder with pushrods, a one-piece crank, air-cooling, and gets its power with slow-revs and large displacement cylinders.
Pratt & Whitney had some excellent chief engineers like Luke Hobbs. While others chose to use more exotic approaches like liquid cooling, 4-valve heads, overhead cams, and high revs to make power, Hobbs wisely kept things simple. As a result, the big Pratt recip engines (R-4360 and R-2800) tended to be more reliable and had less development trouble than other engines in the late 30's and 40's.
terry
RE: Radial engine main bearings
ht
Rod
RE: Radial engine main bearings
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Radial engine main bearings
I watched "When Vacations Attack" last night and a T6 had a crankshaft failure and landed on a highway in front of a couple Hwy Patrol cars. Reminded me of this thread.
My only aircraft restoration project was my cousins Cessna T-50. He got two of them surplus for $600 and we made one flyable. That's the only radial I have ever taken apart and overhauled. I think it was a Jacobs. The plane had two and I only did one of them as the AE that was signing off my work moved and I was not allowed to do the second one. It was just an engine, what was the big deal? Mine worked fine for many years!
Rod
RE: Radial engine main bearings
Here's a local, at DTN:
http://tinyurl.com/3fcldvj
After a lengthy restoration, a test flight was made, but the pilot forgot to put the gear down on landing. Scratch two new props & a pair of fresh "Shaky Jakes".
The pic was taken after the Re-Restoration.
RE: Radial engine main bearings
It was lost in Alaska in the early 60's. Crashed on takeoff with ten people on board. No one was hurt. Robert said he "just ran out of lift"....his words.
Rod
RE: Radial engine main bearings
http://www.skyking.com/
Rod
RE: Radial engine main bearings