The F6F Hellcat

[HoHun]

Hi F4UDOA,

>I don't know if there is a ratio of MAP to HP but I figure 2400HP was about 65" MAP on the R-2800B-8W.

The ratio of boost pressure to power per cylinder is linear.

However, in practice you get increased charge heating with a migher boost pressure, and you're mostly interested in crankshaft power, which means you'd have to deduce the power required to drive the supercharger, so as usual, the devil is lurking in the details :-)

Regards,

Henning (HoHun)

[F4UDOA]

Indeed,

The early R2800B-8 produced 2000HP at SL.

Later the addition of ADI increased HP to 2135HP at SL. Quickly followed by rating increases to 2250HP and then 2300HP in service A/C. However this was done at MAP rating never increasing and never reaching the limit of 60" MAP at sea level. In fact the 2300HP comes at 57.5"MAP.

Go figure.

[gripen]

F4UDOA,
The limits of the B-series R-2800 have been discused here several times and I don't have anything new to say. But to summarize:

With the grade 100/130 fuel and ADI, the B-series R-2800 was rated at 56" in the beginning and later raised up to 64" in the USAF service and up to 59" or 60" in the Navy. High ratings tended to cause overheating problems during the climb.

With the grade 100/150 fuel and ADI, the B-series R-2800 was at least tested up to 70" or higher  but the service ratings are a bit unclear. Probably in the 8th AF quite high ratings were used with the grade 100/150.

gripen

[F4UDOA]

Gripen,

Can you reccomend a good book on the subject? Or should I say what is the best in your opinion?

[Bodhi]

buy R2800 - Pratt and Whitney's Dependable Masterpiece.  by Graham White.

[gripen]

Yep, White's book is the best book on R-2800. There is not much about the ratings or power curves but otherwise it's good, particularly the installations to the airframes are presented well.

gripen

[joeblogs]

http://mysite.verizon.net/vze479py/sitebuildercontent/sitebuilderfiles/doublewasp.pdf

http://mysite.verizon.net/vze479py/sitebuildercontent/sitebuilderfiles/doublewasp2.pdf

Originally posted by F4UDOA
Gripen,

Can you reccomend a good book on the subject? Or should I say what is the best in your opinion?

[SgtPappy]

Originally posted by Bodhi
The Hellcat did not have the same engine as the Corsair.

Differences were minute, as performance is listed as the same, but the early F4u's had a R2800-8 and the F4u-4 an R2800-18W or a R2800-42W (mostly the B's).  The Hellcat series through the -5 carried R2800-10W.

The differences are in carburetor mounting, top on the Hellcat and F4u-4 and bottom on the early F4u's.  Also, the case designs differ owing to different design requirements.

woops.. sorry bout that. i should have specified that the engines had the same type of performance.. didnt actually mean they were the exact same identical engine

[joeblogs]

[F4UDOA]

Joe B,

It seems as if there could only be two choices for the F4U-1 and F6F-3/5 and that would be the 2SB-G and SSB-G.

I am curious as two which one was it though. It is possible that they used different engines however it would be hard to determine exactly which one since the critical altitudes don't exactly match.

[joeblogs]

According to another P&W document, the R2800-10 is an SSB2-G

The R2800-18 is an SSC22-G

The B or C stands for the B or C series, respectively. The double 'S' stands for a 2 stage, 2 speed supercharger

Trouble is, some of Wilkinson's notation does not appear to be P&W's, especially for the later volumes. It might be a later military or a postwar designation.

-Blogs

Originally posted by F4UDOA
Joe B,

It seems as if there could only be two choices for the F4U-1 and F6F-3/5 and that would be the 2SB-G and SSB-G.

I am curious as two which one was it though. It is possible that they used different engines however it would be hard to determine exactly which one since the critical altitudes don't exactly match.