ORIGINAL: Leandros
Grumman F4F-3P and F4F-7
I’ve done some home-work on this. It interests me, also because there are so many discrepancies between the various available sources - and postings here. My main references are a couple of Grumman manuals on the F4F-3, Greene and Denn’s publications and excerpts from a VMO-251 web-site.
Before I get back to technical details I’d just like to clear up the (lack of) connection between the -3P and the -7, they were, as mentioned here in another posting, quite different airplanes, originating from different needs. The -3P was not dropped on the Marines because the Navy didn’t need it or wanted to use it.
Since you're focusing on the two versions, its probably worth noting one other interesting difference. The Marine F4F-3P was actually used
for carrier reconnaissance missions during its career while the naval F4F-7 never was despite it being designed for that specific role.
The -3P was an emergency project, originating from a need created by the upcoming US counter-strike into The Solomons (Guadalcanal). The planners of that operation needed (photographic) information on the enemy positions there, and the Navy had little resources available for the purpose. A simple rebuild of some F4F-3s was the result and the Marines VMO-251 (M: Miscellaneous, O: Observation) squadron was hastily equipped with these and sent to the South Pacific.
I'm not sure it could be called an emergency project. VMO units were supposed to contain at least some camera equipped aircraft. According
to VMO-251's records, it received the first F4F-3s early in April '42 and the first photo-recon modifications were ordered before the end of that
month. On the other hand, the detail planning for Operation Watchtower (Guadalcanal/Tulagi) was only begun after the Battle of Midway.
Their photo missions were finally fulfilled by borrowing B-17’s from MacArthur’s “Air Force”, with VMO-251 personnel manning the cameras.
The B-17s didn't have to be borrowed from Mac. SOPAC command had its own 11th BG carry out the missions.
The -7 was a much more advanced project and meant to be used from carriers. To that I would like to add that one doesn’t have to fly all missions with maximum fuel….
Have you factored in the impact on the narrow stance F4F of large fuel loads shifting in partially filled wing tanks during take-off? It was
remarked upon during initial testing at NAS Anacostia, in NAFC ferry pilot reports and in a Saratoga pilot's comments on his 5 hour "jaunt"
in a F4F-7 on July 8th '42. It didn't sound favourable.
Notes: As a standard the F4F—3 had a GF-5 radio installation with a special radio direction finder incorporated. Would the -7 have had any additional navigation equipment?
Like much of the F4F's other radio equipment in '42, the early GF/RU units had a poor reputation in regards to reliability. In carrier combat
reports of the period, signal strength rather than bearing was the only factor mentioned as being useful. And that still required a USN TF to
broadcast on an intermediate frequency, something they would be loathe to do other than for very short durations. Dead reckoning with a
final assist by the relatively reliable YE/ZB VHF beacon would be the most likely navigation method for a F4F pilot to find his carrier.
As for the F4F-7, there is no mention in the VF reports or those who received the aircraft as a navy hand-me-down (VMO-251 and VMD-154) of
it having any special navigation equipment beyond that of a standard F4F. It's worth noting too that when the ex-navy F4F-7s were flown by
VMO-251 from the New Hebrides to Guadalcanal to begin operations, they had to be guided to their destination by a B-17 for the length of the
600 mile flight, just like the F4F-4's (with drop tanks) were.
I shall elaborate a little on this in a while.
Fred
A few other things to consider before you muse further on this nimble little beast's ability to dance past a frustrated enemy. Firstly, the
F4F-7 suffered more aerodynamic drag due to its fuel dump outlets than a F4F-3 suffered from its wing guns, so you may find that the F4F-7s
top speed was still inferior to the F4F-3 even when lighter.
Secondly, any long range missions launched from a USN carrier well outside the limits of Japanese patrol aircraft range would likely have required
the F4F-7 to still be carrying a large weight of fuel when it reached the target.
And finally, have you actually checked the altitude at which the navy needed the F4F-7 to take its happy snaps of the enemy? It may not have been
what you think it is.
Edited - because Marine VMD units probably don't want to be called VD units.
This was the only sig line I could think of.
