by Tommy H. Thomason

Wednesday, October 28, 2009

Grumman Panther

20 December 2017: The main problem with the Matchbox vertical fin is too abrupt a transition between the upper aft fuselage and the vertical fin as shown in this Ed Boyd picture of his model.
Smoothing the transition and shaping the bottom of the fin aft of the tailpipe would be relatively easy.

2 December 2017: For a discussion of the small difference between the F9F-2 and -5 wing and wing-to-fuselage fairing, see https://tailspintopics.blogspot.com/2017/12/grumman.html

 16 September 2011: Updated for new kits.

Another work in progress for which there was a lot of existing material. This one describes the differences between the -2 and -5 Panther, since there are -2s in 1/72 (the Matchbox -5 is not so good) and a -2 and -5 from different kit manufacturers in 1/48. Click Here for my thoughts on the 1/72 scale -2 kits.

There were three notable shape changes between the -2/3 and the -4/5: the fuselage was stretched by eight inches between the inlet fairing and the dive brakes; the vertical fin was revised (a bit differently than shown here); and the wing leading edge just outboard of the engine inlet was bulged forward with a small flow fence added (the fence was added after initial -5 production and retrofitted to -2/3s so it alone is not a distinguishing feature although the -2/3 fence is a slightly different shape). The -5 also had a small suck-in door behind the bigger one that was on the -2.

You have to do some rivet counting to see where the stretch is but it's there. Note also that the fiberglass reinforcement on the aft part of the canopy is wider on the -5, but this appears to have been retrofitted to the -2, so its absence denotes a -2 but its presence does not necessarily denote a -5.
 
The tail change is a bit subtler than shown on the illustration above. It was actually enlarged all around as depicted here and the -5 trailing edge was 2.75 inches farther aft.
Regrettably, the difference in the shape of the bottom of either fin isn't shown but the following illustration will make up for that. Note that there is also a difference in the gap between the -2 and -5 upper and lower rudders: the -5 gap was rectangular; the -2's was more triangular.
This is another view of the bottom of  the -2's fin:

Other -5 differences are the tail bumper (more on that below), larger stores pylons on the wing, and the configuration of a small "reverse flap" on the wing flap of -5 (See Yves Marino's comment below). On some -5s, the lower aft corner of the larger suck-in door is cut off to clear the engine inlet.


The cockpit was slightly different. The forward end of -2/3 side consoles was stepped up whereas the -4/5 consoles were flat.

Another detail that I hadn't noticed until just now (17 February 2014) is that the tail bumper is slightly different.  It looks like it was part of a fairing on the -2s (see http://www.primeportal.net/hangar/luc_colin3/f9f-2_panther_123652/index.php?Page=3) but not on the -5s (see http://www.primeportal.net/hangar/howard_mason/f9f-5_125295/index.php?Page=2)

Since I limit myself to 1/72nd scale, I don't know anything about 1/48th kits other than what I read on modeling websites. In this case, Pip Moss has measured the Trumpeter -2 and Monogram -5 fuselages and reports that the Trumpeter F9F-2/3 is 9.375 inches long along the waterline (37' 6") and the Monogram F9F-5 is 9.625 inches long (38' 6"). That means that they are one scale foot different in length (a bit more than the actual 10.75 inches but the difference is approximately 1/32 inch, which is easily attributable to measurement accuracy), and both are a bit short but by less than 1/8 inch. On the other hand, Lewin Jones and others have measured the Hobbycraft (same mold as the Trumpeter kit) -2/3 and Monogram -5 and found them to be the same length, which means the Hobbycraft/Trumpeter fuselage is too long. Use the following illustrations to check for yourself.

One problem with the Hobbycraft/Trumpeter F9F-2/3 is the canopy.  See Michael Benolkin's review Here and Tom Cleaver's Here. Click Here for a description of an aftermarket substitute for the canopy and Here for a source for it.

10 comments:

  1. do you know why there are two different shapes for the area between the upper and lower rudders some are fan shaped and others are rectangular

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  2. The F9F-2 had the fan-shaped fixed area between the rudders while the F9F-5's was rectangular. I don't know why Grumman engineers decided to change it but it couldn't have been too significant since it doesn't appear that the change was retrofitted to the -2.

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  3. Quote:"...and the presence of a small "reverse flap" on the wing flap of -5 BuNo 125083 and subsequent".
    As a matter of fact BuNo 125083 is a F9F-2!
    This "reverse flap" was first presented on F9F-2. As per "Handbook Structural Repair Instructions for F9F-2, -4, -5, 5P" AN 01-85FG-3 from 15 Dec. 1950, Revised 15 April 1954 there are 4 groups of F9F models with ot without the flap:
    A.F9F-3: BuNo 122560 to 122565 - no flap
    B.F9F-2 and -3: BuNo 125083 and subsequent - flap with simplified form
    C.F9F-4 and -5: BuNo. 123084, -085, 125080 and -081 - no flap
    D.F9F-4, -5, -5P: BuNo 125082 and subsequent - flap with more complex form

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  4. I'd like to submit a question about the fuselage flaps. I am quite confused, but it looks like some Panthers have the fuselage flaps with a "secondary" hinge, to operate as additional airbrakes as in the Cougar. But Panters should have simple fuselage flaps, operating as flaps only, right? I could not find explanation about this detail. Maybe a retrofit? Or maybe in some preserved Panthers someone just installed flaps coming from a Cougar? Thank you!

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    1. The inboard (fuselage flaps) were different on the some F9F-5s and F9F-5Ps. Part of the flap was hinged to function as an additional set of "dive brakes" (the nomenclature used in the flight manual). These flaps were on F9F-5 BuNos 126642-126669 and BuNos 125893 and subsequent (that's confusing because BuNo 1266xx were not considered subsequent to 125xxx). The same flaps were on F9F-5P BuNos 126271 and subsequent.

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  5. Hello Tailspin, thanks for your clarification above.
    I found another interesting difference between the -2 and -5 version, that is quite confusing to me. I can't figure out the real reason why this details appears, and which part differs in the two versions to give this result.
    Observing carefully the joint line where the aft fuse is attached to the rest of the airplane, in -5 this joint line is located perfectly where the wing/flap trailing edge meets the fuselage. In -2 these two joint lines (aft fuse/fore fuse and Wing/fuse) have no points in common. I noticed this checking pictures of preserved airplanes, and I assume that the wing trailing edge is not a safe reference for locating the joint line of the fuse. Is it possible to explain the reason of this difference? Thank you very much again!

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    1. 30 November Update: Hmm - I've assumed that wing planform and the break location were the same between the -2/3 and the -4/5. I'm now all but certain that the fuselage break for both is FS 299. It does look like the break is a few inches aft of the inboard trailing edge of the wing flap on the -2 whereas it's at the inboard trailing edge of the wing flap on the -5 as you've noted. Drawings are inconsistent but the best ones I have from Grumman suggest that the beginning of the curve on the inboard trailing edge of the wing of the -5 begins far enough farther outboard that it now coincides with the fuselage break as it curves aft. If these drawings are accurate, then the end of the -5's fuselage fairing is also a bit farther aft than the -2's. More later...

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    2. Well, there's your problem. I had forgotten that the -5 outer wing panel was thinner than the -2's in order to put off drag divergence at transonic speeds, 10% versus 12%. The wing thickness at the fold joint was held the same, so to continue the thinness reduction inboard, the leading edge of the wing curved forward and the trailing edge curved more aft to increase the chord locally. The same "thinning" by chord increase was incorporated on the fuselage fairing by extending it farther aft...

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  6. Thank you very much for your effort, very interesting! I remember something about the airfoil thickness, I found where I've read it. Quote from a pdf article "Flight Journal 2002" - by Corky Meyer: "...When I asked the aerodynamic and structural engineers what caused this frightening phenomenon,they speculated that it was probably the result of the wings’ lower torsional strength, as the XF9F-5
    was designed to have a much thinner wing section than the F9F-2".
    At that time I could not understand completely this sentence, because I assumed that the wing had to be the same, and also the airfoil.
    Now this becomes clear!
    Basically this means now that all the drawings usually available on books and internet are not accurate, I assume, since the only difference on planform that is reported is just the L.E.shape close to the intakes.
    Thank you very much for your research and explanation!
    PS: maybe this could be a great topic for a dedicated article on your blog!There are so many Panther lovers around...

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    1. I don't know that many will be as intrigued about your discovery as I was, but I just put a post about it on line: https://tailspintopics.blogspot.com/2017/12/grumman.html

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