FJ-2/3 Nose Landing Gear

Warning: Probably more than you want to know!

First an overview of the nose landing gear from the side.

Note that the shock strut is angled slightly forward and the yoke is mounted in front side of it. The anti-torque scissors on the right side of the strut is angled somewhat aft. The Sword assembly illustration would have you mount the yoke on the bottom of the strut and have the scissors angle forward. Paul Boyer also noted that it would have you put the shimmy damper and the anti-torque scissors on the wrong sides.

This is a closeup of the interface between the strut and the yoke;

Craig Kaston photo

Note that there is a shimmy damper mounted on the left side of cylinder that the yoke is mounted under. It turns out that the yoke is free to rotate within that cylinder since it is basically a sleeve ( there is no nose-gear steering; the pilot steered during taxi and the first part of takeoff and the last part of landing with the brakes).

The shimmy damper does not turn with the nose wheel; it is connected to the yoke where it protrudes at the top of cylinder. What confused me at first looking at pictures of FJs in museums was that lever extending aft on the left side of the yoke. At first I assumed that the museum had left something off but I finally realized that the shiny cylinder at the end of that lever contacted some kind of "ramp" in the nose-wheel well as it was going into the well that turned the wheel 90 degrees so it lay flat under the inlet duct. (On the F-86 that was done with an actuator.) Presumably the shimmy damper provides a centering function when the landing gear is extended.

The line coming down from the wheel well to the bottom of the shock strut pressurizes it to raise the nose for a catapult takeoff. However, the actual routing, at least early on, is along the scissors as shown on this early production (a few were blue) FJ-2:

Here is a comparison of the "normal" strut extension and pressurized for a catapult launch:

However, the strut might be somewhat or fully extended at other times for various reasons.

Also note that when the gear is extended, the top of the forward facing nose gear door goes up into the nose wheel well. As a result, the kit part needs to be shortened (easy) or stuck up into the well (hard).

The Sword nose landing gear strut appears to be too long. I assembled the three big pieces. I drilled an .080 hole in the cylinder in front of the strut and in the yoke to pin them together with a piece of wire since I think simply gluing them won't be sturdy enough.

It looks like I'll need to cut off that thicker section at the top of the strut and "flatten" the tire a bit to get closer to the right "sit". The yoke is also too long but shortening it looks like to much work.

Sword FJ-2 Preliminary

The accuracy of the planform of the new Sword 1/72 FJ-2 has come into question. This was my assessment, using a photo of the Sword FJ-2 wing provided by MVW (Martin) compared to my layout of the FJ-2 wing planform using NAA data for root and tip chords, wing span, and wing sweep at 25% chord. I had some difficulty in establishing the exact location of the trailing edge due to shadow.

In summary, the FJ-2 kit's wing appears to have a little too much wing span and about the right wing sweep depending on the exact location of the trailing edge, which needs some cleanup (and maybe thinning) anyway. Both the root and tip chords look a little too big but not as much as the 6-3's wing. All in all, I'd say its well within my tolerance for error.

Unfortunately, a review of the fuselage picture published by Sabrejet on Britmodeller  indicates a more significant problem. It is clearly somewhat long by 6 to 8 mm (1/4 inch). In checking the comment of another modeler who has the FJ-2 kit that the fuselage was actually slightly undersized relative to the published length, I noticed that the FJ-2 overall length including the extension of the stabilators aft of fuselage of 37' 7" is identical to the 1/72nd length of the kit fuselage from the tip of the nose to the tip of the fairing above the tail pipe. That may be the cause of the fuselage length error.

21 October Update: I now have all three kits in hand and they are lovely to behold.

The surfaces and panel lines are engraved and petite. All the detail parts such as the pitot look as close to scale as you can probably do in 1/72. I haven't checked the fit except for fuselage halves and the wings but so far, so good. The canopy is injection molded in two pieces and clear.

The FJ-2 fuselage and wing are not the same, correctly, as the FJ-3's. The FJ-3s have a slightly deeper inlet and forward lower fuselage and a different air scoop on the upper fuselage aft of the break. The FJ-3s have a cambered leading-edge wing that has a representation of the 6-3 planform change that differentiates it from the -2 and blue FJ-3s slatted wing, which were similar to the F-86E's and early F's. (Remarkably, the FJ-3 wings have three of the four barricade snaggers—these are teeny things in 1/72—on the leading edge of each wing, missing only the most outboard one.) They also have alternative rudders and horizontal stabilizers with the external ribbing on the trailing edge whereas the FJ-2 kit does not.

Both the FJ-2 and FJ-3 fuselages are a little less than 1/4" too long. Theoretically you could take 1/8" out of the aft fuselage (but you can't do it at the break as I had hoped) and about 1/8" off the inlet. I'm for certain going to forget sectioning the aft fuselage. However, in my opinion, the downward curve in the top of the fuselage forward of the windscreen is incorrect (it needs to curve down more) and the bottom of the intake curves a bit forward and shouldn't.

There appears to be enough plastic in both places to get closer to what I think is correct. See http://tailspintopics.blogspot.com/2017/10/sword-172-north-american-fj-23-furies.html for one approach.

The only difference besides decals between the -3 and the -3M kits is that the latter has two Sidewinders and the requisite pylons. Both have the inflight refueling probe.

Getting enough weight in the nose to keep it from tail sitting might be interesting. A little scraping of the upper fuselage at the forward end of the windscreen appears to be required for a good fit. My guess is that putting the nose gear together (seven pieces!) might need to be altered from the instructions with respect to the location of the nose-wheel yoke, which may be too deep otherwise by a teeny bit. I'm pretty sure that the top of the nose gear door should be inside the forward end of the wheel well when it was extended.

More later...

VA-72 A4D-2

In response to a request...

F8F-2P Propeller Hub

Note: The answer didn't take long - see comment below.


I recently took a close look at the propeller on this F8F-2P:

It appears to have an extension on the propeller hub. Moreover, the extension looks like a censored detail.

This same hub and appearance of censorship is on other -2P photos.

I did find one that showed the feature, uncensored or at least not painted white.

I didn't see this extension on hubs of F8F fighters in a quick survey of other photos.

The pod under the wing of the F8F-2P in the top photo is not a mystery. It contains a trimetrogon camera* capability:

Lightening the picture reveals a port on the right side. My guess is that there was also a port on the left side and one on the bottom.

*

Trimetrogon cameras in a B-17

F8U Two-Position Wing

The F8U was one of the few production airplanes with a variable-incidence wing, with the wing raised for takeoff and landing to reduce the nose-highness of the fuselage for those flight conditions while still providing a wing angle-of-attack that maximized lift and therefore minimized takeoff and landing speed to meet carrier-basing limitations.

It was in part the result of Vought's experience with the F7U Cutlass and the Navy's dislike of its nose-high attitude on takeoff and landing. The F7U-3's radome, cockpit, and canopy had to be redesigned to provide adequate visibility over the nose before at-sea carrier landing qualification trials were authorized.

When Vought proposed what was to become the F8U, the need for low drag for maximum speed restricted the height of the canopy. The height of the landing gear, particularly the nose gear, was also to be minimized for various reasons, including weight reduction and to avoid problems experienced with the F7U's long nose landing gear. However, these two design stipulations were difficult to accommodate with the longer aft fuselage of a conventional tailed airplane with an afterburner.

The two side views in the following illustration are to the same scale with the main landing gear wheels and static ground line (approximately the landing attitude relative to the deck) coinciding. Note that the aft fuselage of the F8U would strike the deck with the nose raised only a little over five degrees.

The result was the incorporation of a two-position wing to allow for both adequate visibility over the nose for carrier landings and aft-fuselage clearance on touchdown.

F4U-4 Lancer II Reno Air Races

Once upon a time, I was the pit crew on F4U-4 BuNo 97259 at the 1967 Reno Air Races. When I say "the" pit crew, I was it. The rest of the team were the co-owners, Gene Akers and Mac Mendoza. Gene was the pilot and Mac was the head (and only) mechanic.

When I met them, N6667 was parked behind a hangar at Fox Field, Lancaster, California and I was working as a McDonnell flight test engineer at Edwards AFB.

It had come a long way from its disposal by the Navy, circa 1960.

June 1967

I volunteered to be their pit crew at Reno for room and board that year. It was a shoestring operation, including the first paint job.

If you look closely at this picture, you'll see that the right tire is missing.  Another Corsair arrived with a failing engine and the pilot blew a tire when he landed. We loaned it to his crew to get him off the runway.

 Basically, all we did was fill the oil and check the gas between races. Gene and Mac were there with their wives and went to bed early. I went into Reno with some of the other crews.

A couple of mornings I made a functional check of the oxygen system in a vain attempt to accelerate the end of a hangover.

This picture was taken 22 September 1967. I'm at the left wheel, ready to pull the chocks.

For the 1968 race (I wasn't there; I had gone back east to graduate school), Gene and Mac found a sponsor to give it a real paint job.

Several years ago, I looked up Mac and asked him what color it was. He didn't remember, other than it was a "bright green" that was picked from color chips at the aircraft paint shop they took it to.


More later...

USAF/VNAF A-1Es

A work in progress on the non-USN wide-body Skyraiders. Rely on the following at your own risk. Comments welcome.

Douglas AD-5 Armor

Like the single-seat AD (A-1), the AD-5 had a bolt-on "armor" kit. (For the single-seat armor, which was slightly different, see http://tailspintopics.blogspot.com/2013/07/ad-armor-all.html) There was some internal difference shown in the SACs of the basic AD-5 (A-1E) and the night attack AD-5N (A-1G).

AD-5 (A-1E)

AD-5N (A-1G)

Exterior Armor Photos

Lockheed P/F-80 Shooting Star Tip Tanks

It may seem like I'm going off the reservation again with this topic but it does, peripherally, pertain to a airplane operated by the U.S. Navy.

It is also a work in progress, since I personally don't have a lot of material to work with. Gerry Asher has yet to fully weigh in, so there will be changes. Since I posted it today, I've modified the source of the second and the final tank to be Fletcher Aviation Corporation, an aerospace manufacturer that subsequently became Sargent Fletcher a decade or so later.

The P-80 wing tip incorporated a shackle from which to hang a jettisonable fuel tank or 1,000-lb bomb (the requirement to do both dictated its location under the wing; otherwise the tank would have been mounted in-line on the wingtip to maximize the end-plate effect).

The original 165-gallon tip tank was a thing of zaftig beauty, with a rounded nose and sculptured afterbody, that was mounted directly under the wing tip and smoothly faired into it.

Note the flange going from nose to tail on the top and bottom of the tank since it was assembled from two halves.

This tank was sometimes dropped in flight or otherwise damaged and needed to be replaced. As a result, a cheaper design was procured from Fletcher.

Note that it has a pointed nose, a constant-diameter midsection (barrel), and a more conical afterbody. It would appear that this tank was manufactured in three sections: forward, mid, and aft that were then assembled together.

It is this tank that was the basis for the so-called Misawa tank, which added two more of the barrel sections to increase its fuel capacity by a much-needed 90 (some sources state 100) gallons (Misawa was the Air Force base in Japan where this kludge was created: see http://yellowlegs-and-others.com/Equipment_Vehicles_Weapons/Misawa_Tank.html).

However, Lockheed, Fletcher, or some other source designed and manufactured yet another tank that had a higher fineness ratio and a rounded nose. This tank is frequently seen on RF-80s:

And also on most U.S. Navy TO/TV-1s:

And on early T-33s and F-94s:

Note that it appears to be slung somewhat lower than the other tanks with a fairing enclosing the attachment to the wing. This is my best guess as to its size and shape.

The final F-80 tank, similar in configuration to the Misawa tank, was also procured from Fletcher. It was mounted inline with the wingtip rather than under it and sported a side-mounted fin on the afterbody. It increased the capacity of the tip tank to 230 gallons.

I'd appreciate information on and links to drawings and dimensions of these tanks.

A-1E Yankee Escape System

For more on the Yankee system, see https://www.youtube.com/watch?v=8Yw8g1Soigk

The US Air Force installed Stanley's Yankee escape system in its A-1E Skyraiders as well as its single-seat ones. The Navy incorporated it in single-seat Skyraiders in at least two attack squadrons late in their fleet service but not in any of their wide-body A-1s.

The rocket was mounted almost vertically rather than almost horizontally as in the single-seat Skyraider but the result was the same:

From the USAF Flight Manual:

From a Stanley Aviation Brochure:

From Ed Barthelmes excellent A-1 Skyraider Walkaround*:

* If you don't have it, you should buy it: