Quote:
Originally Posted by majorfailure
Again: Just because an an engine model does more hp at some alt, it does not mean it does more hp at any alt. 5kft is near FTH of first stage of F4F -good alt for it. Try at 5km alt - FM-2 will be better than F4F.
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Every source I have shows the FM-2 superior to the F4F-3/4 up to around 18-20,000 ft. The same site you link has tests for both which indicates that the FM-2 at 5K will do a bit over 310mph, or within an eyelash of 500kph; the F4F-4 at 4500 ft is listed at 283 mph or
455 kph, a difference I consider significant.
I can't find much mention whether the engine was a plain vanilla -8 or -10, or a -8W or -10W, which indicates water injection, but it was not always noted back then. That still leaves the questionable performance of the F6F-5, which should do
at least 330 mph at that altitude, or about 15-20 kph more than I could get in seven test runs.
I don't know if you're a native English speaker, major, but we refer to this sort of thing as "cherry picking." I'm sure you'll find it a useful term
.
Like many high performance fighters, the rudder corrections for extreme changes in speed (as experienced in a sudden climb or dive) could not be rolled in quickly enough on the Hellcat, sometimes requiring the pilot to exert pressure on the rudder pedals; the same phenomenon was noted for the P-40, P-47, P-51 and the Corsair to some degree,
much greater in the case of the P-40 (meaning that the Warhawk was a couple of orders of magnitude worse than the Hellcat), about the same as in the P-47 and less in the other types. If the rudder issues you refer to consist of the notation on page 8, it was a minor issue and quite acceptable (and clearly superior to the rudder input demands placed on a pilot flying a Bf 109 or FW 190). AFAIK, it was common to all models of the Hellcat, and considered a fairly mild vice.
Edit: The reason it was mentioned is that the original contract probably specified that rudder forces would be trimmable throughout the aircraft's performance (I'd have to re-read Tillman's book to be sure); this turned out to be impossible with the engine and propeller changes from the original R-2600 and Curtiss Electric combination envisioned for the Hellcat, so it was just noted and signed off on every acceptance test rather than go to the massively complicated task of revising all the contract documents in the possession of Grumman and the Navy Department (this was the age of hand-typed documents and carbon copies, remember; they hired thousands of young women to type and file and keep track of all the hard copies, and had warehouses full of the original documents) and getting them re-signed. I can tell you from personal experience that some government contracts still get this sort of standard waiver treatment for minor issues and that if the government rep who had to inspect the paperwork was transferred, you'd
better be able to produce the original paper trail for his or her replacement.
cheers
horseback