by Tommy H. Thomason

Thursday, December 30, 2010

F8F Bearcat: -1 vs -2


The most obvious external differences between the Grumman F8F -2 Bearcat in the lead picture above and the F8F-1 were the 12" taller vertical fin and rudder and the 20mm cannon armament (the latter was also a feature of the F8F-1B, the B suffix indicating a change in armament) indicated by the longer barrels and the bumps on the upper surface of the wing.
The drawing above turns out to be incorrect. See http://tailspintopics.blogspot.com/2016/07/grumman-f8f-bearcat-vertical-tail.html

A not so obvious difference was the windscreen. See  http://tailspintopics.blogspot.com/2016/07/grumman-f8f-bearcat-windscreen.html

There was also a difference in the engine installation. Reportedly (see Davis Gandees comment below) only the first 23 "pre-production" F8F-1s had 5 exhaust stacks.

According to Gandees (and a subsequent comment by anonymous), the remaining F8F-1s had three exhaust stacks. The following sketch showing a fairing added to the trough to cover two lower stacks is is therefore incorrect.


The -1 shown here has the production exhaust trough with the lower side raised above the wing to smooth the flow over the wing and horizontal stabilizer.

 This is the -2 trough with three exhaust pipes.

Air that had passed through the oil coolers was dumped through two "shutter" controlled doors between the inner main landing gear doors. These are the doors on the F8F-1:
Picture by Craig/J361 on Hyperscale

These doors were a slightly different configuration on the F8F-2. They were longer, extending farther forward, and had a scalloped cutout on the inboard side.
Picture by Ron Cline

A fixed oil cooler vent was also added across the bottom of the aft end of the -2 cowl (Mark Hayward picture from the Prime Portal F8F Walkaround):


Mike West of Lone Star Models sells resin 1/48 F8F-1 and -2 cowls as well as other F8F improvements. Chris Bucholtz of Obscurco also offers a replacement F8F-2 cowl for the 1/48 Hobbycraft kit.

For much more detail on the F8F Bearcat and operational usage, see Steve Ginter's excellent monograph written with Grumman's Corky Meyer. It's also available from Sprue Brothers.

3 comments:

  1. I love to research all air platforms. This as good as it get's.

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  2. Actually, only the 23 pre-production F8F-1s had 5 exhaust stacks. Production F8F-1s had 3 stacks per side. The F8F-2s had similar troughs and the 3 exhaust stacks protruded slightly farther aft. The incorrect 5 stack info came from the mostly accurate Squadron Bearcat in Action.

    Davis Gandees

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  3. The above drawings and photos illustrate the 5 stack arrangement with the lower stack level with the wing upper surface. This created disturbed spanwise airflow over the top of the wing, also disturbing the air over the horizontal stabilizer. This was discovered in during high speed test in March 1945 at the full scale Ames wind tunnel in Langley, Virginia. The 5 stacks were combined into 3 raising the bottom of the exhaust trough 4 inches above the wing solving the problem. This information was related to me in a 2006 phone interview with the late Grumman test pilot, Corwin "Corky" Meyer who flew much of the development test with the XF8F-1. Meyer included this info on page 7 in the Ginter Publication "Grumman F8F Bearcat". I hope this clears up this confusion that I believe was started with the illustration on page 32 of the Squadron "F8F Bearcat in Action".

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