Originally posted by fdiron
I got my primer pump information from a book that I read years ago. I cant even remember the exact name of the book, it was 'P51 Mustang' I think(probably around 300 pages). It was a collection of stories about the P51. There was also a book just like it about the C47. In the P51 book it talked about a p51 getting hit in the cooling system and then the pilot using the primer pump. Anyone know the book I am talking about?
This story commonly appears, mostly based upon Jim Goodson's acount of his P-47 overheating and Godfrey nursing a Mustang home
with a very minor leak.
As I've said, I brought this story to several P-51 pilots, including Arthur Heiden (20FG), Stan Richardson (55th FG) who both flew the P-51 (and P-38) in the ETO. Also, I exchanged comments with Dudley Henriques (past President of the International Fighter Pilots Fellowship) and Vlado Lenoch who currently flys a P-51D. Every one of these guys said the same thing (paraphrased by me): "If it (the Mustang) had a serious coolant leak, the engine would have seized within minutes regardless of what the pilot tried to do." That is what I mean when I say that the story has been misinterpreted. No way would using the primer pump offset the loss of total system pressure, or worse, the loss of all coolant. Yes, using the primer can keep an engine hovering at the temp readline from overheating if, and only if, the temperature is marginally over the limit. Exceeding the max temp by just 10 degrees C can lead to rapid failure. So, if using the primer keeps it close to the limits (121C), the engine will probably survive. As it was, Godfrey's Merlin was a write-off. Merlins were especially cranky about cylinder head temperature. Too high and you get detonation, which makes even more heat. Too low and the spark plugs will load up and foul. Indeed, during extended cruising, pilots were instructed to "run up the engine" to 45 in/Hg @ 2,900 rpm to clear the plugs once every hour. Failure to do so could find you with a severely misfiring Merlin when you push up the throttle in response to encountering the enemy.
My regards,
Widewing
