AMT 1/48 F7F-3 Tigercat Build Review

By Kerry Wilcoxon

Background

Shortly after the Battle of Midway in June 1942, the Commander of U.S.S. Yorktown Fighter Squadron Three (VF-3) and veteran of the battle, Lt. Commander John Thatch sat down to write an assessment of the F4F-4 Wildcat, the premier American Navy fighter at the time. The victory at Midway had been tempered by the loss of Thatch’s own Yorktown from air attack and by the inability of American fighters to protect either the carrier they were operating from or the dive bombers and torpedo planes they were escorting. Thatch was blunt, ending his scathing critique of the Wildcat with the statement, “If we expect to keep our carriers afloat we must provide a VF [fighter] airplane superior to the Japanese zero in at least climb and speed, if not maneuverability.¹ While the accuracy of this statement was proven early on in the war, it was the realization of fears expressed by the U.S. Navy long before the war began.

The basic tenant of aerial combat requires that fighter aircraft be able to intercept and then shoot down opposing aircraft before they can do harm. To be successful a fighter must be capable of matching or beating the enemy in maneuverability, horizontal speed, and rates-of-dive and climb. The single-engine fighters available to the U.S. Navy at the start of the war were heavy and underpowered and would prove to be inferior in climb and speed performance to Japanese fighters they would soon encounter. As early as February 1937, the U.S. Navy recognized this shortcoming and concluded that to provide adequate fleet defense, “…it will be necessary to go into a two-engine, single seat fighter design.²” This conclusion would ultimately lead to the development of the F7F Tigercat.

Developmental History

The first experimental twin-engine naval fighter, the Grumman XF5F Skyrocket, could out-climb not only current front line Navy fighters but all prototype navy fighters under development and several land base aircraft in production at the time.³ Unfortunately, the unconventional design of the XF5F suffered from other problems that prevented its development beyond the prototype stage. Still the concept of a twin-engine naval fighter took shape with the Skyrocket and its off-spring, the XP-50 and XP-65.

Concept development continued through the later part of the 1930s and into 1940s, culminating in June 1941 when the Navy ordered two prototypes of the Grumman Tigercat, the XF7F-1. Coincidentally, this was the same day as the Navy ordered prototypes of the XF6F-1 Hellcat. Since the Hellcat was a more conventional design and thus represented the best chance for rapid development, it was given engineering priority. Grumman did not start the design work on the XF7F until the late spring of 1942. With the first flight of the Tigercat taking place roughly a year and half later in November 1943.⁴

Flight testing extended into the spring of 1944 with both Grumman and Navy pilots. The performance of the aircraft at that time was 375 mph at sea level, and 429 mph at 22,000 with a service ceiling of 42,000 feet and a range of 1160 miles. Most impressive of all was the Tigercat sea level rate-of-climb which under combat power and no external stores was 4,580 feet per minute.⁵ Putting this last number into perspective, the Tigercat could climb from sea level to 20,000 in just in 5.2 minutes⁶. To reach the same altitude, the F4F-4 Wildcat would take just over 12 minutes⁷, the F4U-4 Corsair would take 8 minutes⁸ and the F6F-3 Hellcat would take 7 minutes.⁹

The Tigercat also sported an impressive array of ordinance. The F7F carried four 50 caliber machines guns with 300 rounds each in the nose and four 20 mm cannons with 300 rounds each in the wing roots. These would have out gunned anything in the Japanese arsenal at the end of the war and could have offered murderous ground support for advancing troops. In addition, the aircraft could carry up to 4,000 pounds of bombs and up to eight five-inch rockets. The bomb load alone was more than twice what could be carried by the Navy’s premier carrier based bomber, the TBF Avenger.¹⁰

Design Problems

Like any unique aircraft, especially before the age of computer aided design, the Tigercat development and flight testing uncovered several major problems with the design. One of the first was the problem of low speed directional stability especially in relation to roll, which was discovered late in testing. The remedy was to increase the size of the vertical stabilizer to reduce the dihedral affect. Although important, this change was not considered critical enough to slow production and was not introduced into the configuration until 107th aircraft production.¹¹ Some of the pictures of the -2N night fighter and -3 day fighters in flight still show the smaller vertical stabilizer.

The second problem that was never resolved had to do with the center-of-gravity which was so far aft that the Tigercat was prone to enter into a flat spin within a few rotations of a normal spin. Once in a flat spin, control surfaces produce no lift and recovery is difficult. Any solution would have required major redesign which would have taken time; instead spin testing was removed from the test profile. Unfortunately not in time to save the life of one pilot who ended up spinning into the ground.¹²

But by far the most serious problems encountered during the Tigercat development were structural flaws encountered during the high loading environment of carrier landing. These problems would have the greatest impact on the development, deployment and ultimate life of the Tigercat. In preliminary qualification testing on a simulated carrier deck, the unique Y-frame tail hook developed for the Tigercat failed.¹³ This resulted in the decision to deploy the Tigercat only from land based Marine units. The tail hook assembly would later be strengthened enough to allow the F7F-3N Tigercat to become the first twin-engine aircraft to land on an aircraft carrier. Unfortunately, during these tests a second structural problem arose with the wing-root which further limited the use of the Tigercat on carriers.¹⁴

Operational History

Despite the failure of carrier qualification, the navy began equipping Marine fighter squadrons with Tigercats in early 1945. VMFN-531 was the first to be equipped with the -2N night fighter and VMF-911 was the first to be equipped with the -3 day fighter. Both units were on Okinawa preparing for the planned invasion of the Japanese mainland when the war ended.¹⁵ After the war, VMF-911 along with its F7F-3s would be absorbed by VMF-312 which had previously converted from the F4U Corsairs they flew during World War II. VMF-312 would train with the Tigercat from early 1946 to 1947. Sometime after that the squadron converted back to the F4U-4 which they would eventually take to Korea.¹⁶ The night fighters including the -2N, -3N and ultimately the -4Ns would be used in post-war service and combat in Korea but long before Korea, the F7F-3 day fighter would be phased from the fleet and would never see combat.

The reasons for the early retirement of the Tigercat are not clear however, the most logical reason seems to be its failed carrier qualifications. Since carrier deployment was a necessary requirement for any naval aircraft, it may simply have come down to using what had already worked which in this case would have been the F4U an aircraft with a proven track record for ground attack and close air support, the new role envisioned for the F7F-3. This decision also took place in the back drop of the inter-war period when jets were quickly taking over the role of frontline fighter. In any event, by the outbreak of hostilities, there were no operational squadrons flying the -3. The remaining inventory was converted to night fighters, drone control aircraft or simply stricken from the inventory. With this inglorious ending, the F7F-3 Tigercat passed from history without its potential as guardian of the fleet ever being realized.

Tigercats Today

Today, the remaining F7F-3 Tigercats are on display at various air museums around the country including the Naval Air Museum in Pensacola, Florida and the Davis-Monthan Air Museum in Tucson, Arizona. There are a few that are still airworthy including at least one that was recently (2005) converted to a -2N-ish configuration so that the pilot could carry passengers. To get a sense of what the Tigercat looked like in flight there are several videos of the F7F available on Youtube.com but probably my favorite is the 1945 news real footage that shows the -3 in being put through its paces (http://www.youtube.com/watch?v=_pv2teDEDVw). Although grainy, the footage provides a glimpse into to the power and beauty of the Tigercat.

Project

The F7F-3 Tigercat has been one my favorite aircraft since I was a kid. I remember building the Monogram version in 1/72nd scale but when I decided to build the kit as an adult, I wanted to build in a larger scale and the only choice was the excellent 1/48th scale AMT/Ertl F7F-3 kit produced in the mid-1990’s. Since AMT/Ertl no longer produces this particular kit and Italeri, the company that now owns the F7F molds has not re-released a -3 variant, the only outlet for finding the kit was e-bay or other on-line auction sites where it can generally be found for between $10 and $20 (mine cost $15 and was still in the factory sealed box).

Kit

With kit in hand I, opened the box and found four spurs of gray styrene parts, one sprue of clear parts and soft rubber tires. In addition, the kit comes with a large sheet of decals and two separate assembly sheets, one for the general assembly and one for the finished painting and decal application.

My particular kit had quite a bit of flash especially on the sprue with the wings. All of this cleaned up fairly easily and there were no other obvious problems with either the mold or the plastic. The surface detail is rendered in crisp recessed panel lines and although the cockpit was fairly basic, the wheel wells, gear doors and engines had enough detail to satisfy intermediate model builders like myself.

The assembly instructions turned out to be not very useful especially with final construction. The first 11 steps are shown in separate boxes on the front of the large sheet but the final assembly including the attachment of wings, horizontal stabilizer, and landing gear are all thrown together on one illustration on the back of the sheet. The assembly is not so complex that this created a big problem but some of the assembly steps on this side would have been better described with specific illustrations.

The separate painting and decal instructions were an odd touch as well since the three versions offered are all essentially the same overall sea blue and the decal variations are not that different from each from each other. One of the variants which depicted a Marine Corp version also called for the installation of an ADF antenna which, as the instructions indicated was not included.

Overall though the packaging and presentation of the kit is very nice and the complexity is not overwhelming.

After Market Features

Since there were so few -3s built, I knew that my choices in paint schemes would not be extensive so I decided to compensate by adding details to make the finished product look better. To enhance the cockpit and wheel wells I used cockpit instrument decals produced by Mike Grant Decals (SKP048). To balance the finished plane on its landing gear I applied self-adhesive 7-gram lead ballast weights from Great Planes (GPMQ4485) and for more realistic looking landing gear, I used Scale Aircraft Conversion’s white metal F7F landing gear (SV48008). To display the cockpit open and slid back on the fuselage, I also used the Squadron Signal vacuformed canopy (SQ9593). Finally, to add realism to the 20 mm wing mounted cannons I used the hollow shafts of two #22 hypodermic needles purchased from my local drug store.

Construction

The AMT Tigercat turned out to be one of the easiest kits I have ever built. The part fit is exceptional and the assembly is straight forward with a few exceptions noted below. I was pleased with how well the wings and horizontal stabilizers mated to the fuselage and how easy it was to set the dihedral. The seams in the fuselage and wings were easily filled in with gap filling super glue and there was very little sanding required.

I started with the cockpit area which I painted in Testors Model Master Interior Green enamel (FS-34151) except for the instrument panel and side consoles which I painted flat black. I added detail to the panel and consoles by painting the switches and handles silver or red and then used the Mike Grant cockpit gauge and placard decals to add detail to the main instrument panel, console and cockpits sides. Using reference photos of the actual instrument panel and cockpit, I tried to match the instrument style and positioning with the appropriate decal from the sheet. When I was finished with everything, I gave the assembly a light wash of burnt umber to add more definition.

With the cockpit mostly assembled, I then turned to adding the nose weights to balance the finished model on the tricycle landing gear. When I first began working on the project, I thought it was strange that there was no mention anywhere in the instructions on how to balance the model with ballast. The kit includes a scale oil drum and box that are intended to fit under the tail to prop up the completed model but there is no reference about nose weights.

Undaunted by this apparent oversight, I forged ahead using my Great Planes self-adhesive lead ballast weights. There is not much room in the nose for adding weights but I ended up covering the upper side of the nose wheel base behind the instrument panel with about 40 grams of lead. The ballast weights are very easy to work with and the self-adhesive backing is monstrously strong so once they were in place it took an X-acto blade to remove them. Since I had filled almost every useable bit of space in the nose with ballast and the assembled fuselage felt like a brick, I thought there would be no problem with balancing the finished kit so I completed the assembly.

I was wrong!

When I installed the Scale Aircraft Conversion metal landing gear, which attached perfectly to the slots intended for the AMT landing gear, I placed the assembled kit on its wheels and the aircraft promptly sat back on its tail as if I had added no weight at all. I had to add another 21 grams to each of the engine nacelles just forward of the landing gear before it would balance on its nose wheel. Even now, the finished model will fall back on its tail if bumped hard enough. The one positive side affect of the added weight is that it makes the soft rubber tires flex more realistically.

After all of the weight I had to add to the finished model my decision to use the SAC metal landing gear looked particularly wise in retrospect, never mind that I originally wanted to use the landing gear for added detail. It is hard to imagine the AMT supplied plastic gear struts holding up under the relatively intense weight of all that ballast. This may explain why AMT did not provide recommendations for adding ballast in the instructions.

Apart from the balance issues, the only other problems I experienced with assembly were attaching the main landing gear doors and arranging the 5-inch under-wing rockets. The main gear doors have three dimpled tabs to attach (in theory) to the holes inside the engine nacelles. I could not get all three to attach no matter how hard I tried or what angle I held them at so I finally had to remove the center tab from each of the gear doors. The modified doors fit much better.

Mounting the 5-inch rockets was not much of a problem but the instructions were misleading since it shows them mounted with fins parallel and perpendicular to the ground but in practice, I could not mount four per side without the fins arranged diagonally to the ground.

The final assembly step of note for this model was my use of hollow shafts of two hypodermic needles for the barrels of the 20mm wing cannons. The needle shafts were remarkably easy to work with, once I convinced my pharmacist what I was using the needles for. I cut the shafts off with a Dremel saw and removed the burrs from the tip. They painted up fairly well and while they dried, I drilled out the attachment holes in the wing roots. The finished tubes were attached using super-glue.

Painting and Decals

Before I started I knew nothing about the history of the F7F-3 but wanted to build a Tigercat from an active duty Navy squadron. I soon learned that there were no such squadrons or aircraft but the kit did offer a Navy version in the standard delivery paint scheme (Aircraft Number: 80462) along with two Marine Corps aircraft so I would still be able to build a Navy Tigercat after all, or so I thought. Photographs of the “462” aircraft are some of the more common -3 photographs available on the web and the distinctive numbers on the engine nacelles (the last three of the aircraft number) at least provide a little style to the paint scheme. Because I knew the exterior would be fairly monotonous sea blue, I also decided that I would install all of the ordinance and external stores that I could to break up the blue. What I did not know at the time was that this particular aircraft probably never flew with any external stores at all. In fact, soon after the in-flight photographs were taken, the “462” Tigercat day fighter was converted to a two-seat -3N night fighter and ended up with the Marines so its career as a -3 day fighter in the Navy was short lived.¹⁷

Despite the news, I continued on with the “462” scheme. I painted the overall aircraft with Testors Model Master enamel spray Gloss Dark Sea Blue (FS-15042) which I applied without a primer coat. There is some question of the color of the interior wheel wells which are called out as being interior green but which probably should have been dark sea blue as well based on the common Navy paint schemes of the time. I decided to use the interior green as recommended in the instructions, finished with another light wash of burnt umber for color variety.

Since this aircraft never saw deployment as a -3, there would have been very little weathering to the exterior so I settled for white/grey exhaust streaks on each nacelle which are visible in the photograph and would have occurred during the early flight hours of this aircraft.

The kit decals are not good which was a surprise to me since the rest of the kit was so well done. The decals are thick and don’t conform well even to the relatively smooth surfaces of the aircraft. I recommend cutting away as much of the clear base material as possible before applying to avoid yellowing and then don’t spare the Microsol decal solvent. This is especially true for the engine nacelle decals. I also thought that the stars and bars provided for the wings were too small compared with the photo so I ended up swapping them out with larger versions from my drawer of spares.

Photo courtesy of Jacques Trempel care of jacquest@sympatico.ca

Conclusions

Ultimately, the build turned out well and conveyed the image I had in my mind of what the Tigercat looked like. I would recommend this kit to anyone interested in aircraft of the post-WWII era. Just be prepared to add lots of ballast!

References:

1. Lundstrom, John B. The First Team: Pacific Naval Air Combat from Pearl Harbor to Midway, Naval Institute Press, 1984, p.441
2. Lucabaugh, David and Bob Martin, Grumman XF5F-1 and XP-50 Skyrocket, Naval Fighters Number 31, Steve Ginter Publications, 1985, p.3
3. Ibid, p.16
4. Scarborough, W.E., F7F Tigercat In Action, Squadron/Signal Productions Inc., 1986, p.5
5. Ibid.
6. NAVAIR-1519A (Rev 9-44), Airplane Characteristics and Performance F7F-3N, Bureau of Aeronautics, Navy Department, March 1, 1946, p2
7. Report No. 1471C, Detail Specification for Model F4f-4 Airplane, Grumman Aircraft Engineering Corporation, October 21, 1942, p. 5
8. Report No. 7289, Detail Specification for Model F4U-4 Airplane, Chance Vought Aircraft Company, Publication Date Unknown, p. 13b
9. Report No. 2422B, Detail Specification for Model F6F-3 Airplane, Grumman Aircraft Engineering Corporation, May 1, 1944, p. 7
10. Publication AN 01-190EB1, Pilots Handbook of Flight Operating Instructions Navy Model TBM-3 Airplane, Grumman Aircraft Engineering Corporation and U.S. Navy, August 15, 1945, p. 71
11. Scarborough, ibid. p.5
12. Meyer, Corky H., F7F Tigercat: The Untold Story, Flight Journal, August 2002, p. 4
13. Scarborough, ibid. p.7
14. Ibid. p. 31
15. Andrews, Hal, F7F Tigercat, Naval Aviation News, July-August 1998, p.42
16. Crowder, Michael J. United States Marine Corps Aviation Squadron Lineage, Insignia & History - Volume One - The Fighter Squadrons, Turner Publishing Company, 2000, p.176
17. Andrews, ibid. p.40