Skyhawk Details

Ronny Svendsen asked some interesting questions about the use of red on the Skyhawk crush points and the A4D-2N (A-4C) radome change that caused me to go back and review those details. The crush-point question resulted in the post just before this one. I've just added some additional pictures to it and a comment by Rick Morgan with respect to the purpose of all that red. I also went looking for more radome examples. I had originally mentioned the change from the A4D-2N nose with the large black radome to one that was mostly gray/white with a small area of white or black on the tip. See http://tailspintopics.blogspot.com/2010/07/a4d-skyhawk.html.

It appears that this change may have been made with some urgency, because I've now seen several examples, some furnished by Ronny, of the later radomes that are probably field replacements because they are a solid gray that doesn't match the color of the forward fuselage and the black anti-glare paint does not extend forward onto the radome as it subsequently would. This is an example:

The new radomes also appear to come from different sources (two are tipped in white and two in black) which suggests an effort to field replacements as quickly as possible by buying them from more than one manufacturer.

I'd still like to know why the change was made and how the new radome differed in construction from the original one. For example, was the transmissivity now limited to the small area on the tip of the nose or was that just an erosion-resistant coating?

Painting Crush Points Red

One notable feature of the Navy's gray/white paint scheme was the red identification of crush* points: flaps, slats, speed brakes, and landing gear doors. Except it was not always so. In this picture, reportedly taken in May 1960, neither the A4D-2 nor the F4D-1 have red-painted slat wells or red-edged landing gear doors.

(Also note that the F4D has probably been pushed back into its parking place, since the nose wheel is facing backwards.)

In fact, it is fairly rare to see any pictures of the F4D with red in the slat wells and very rare to see one with red edges on the landing gear doors (except for one restored for a museum). This one was photographed at the Paris Air Show in May/June 1961 as confirmed by Bernard Thouanel. The only obvious red is on the edges of the wing at the fold joint but there does appear to be red on the wing that would be covered when the slat closed (but definitely not on the edge of wing inboard of the slat).

Note the inflight refueling probe that has been added to the left drop tank, a change adopted fairly late in the F4D's career.

However, there are clear examples of later F4Ds with red-painted slat wells:

The Navy began the change from overall blue to gray/white in February 1955 (see http://tailspintopics.blogspot.com/2009/12/changing-from-blue-to-graywhite.html). At the time, the interior surfaces of speed brakes and wing flaps and their wells were to be painted red, according to Mil-C-18263 dated 23 February 1955. The interior of slats and their wells was added by Mil-C-18263A dated 16 July 1956, although this was reportedly "released at a later date." Red on the edges of doors was decreed by revision B of Mil-C-18263 dated 12 February 1959.

So how come, assuming that the date given with the photo is correct, do those airplanes have grey slat wells and all white gear doors? The answer is probably that it takes time to revise contracts in the case of the manufacturers, and create the requisite documentation in the case of the government repair and overhaul facilities. With that in mind, these changes were generally issued with a generous amount of time before compliance was required.

And even then there are examples where the main gear doors have a red edge and the nose gear doors do not.

 It would appear that the A4D Skyhawk didn't have red edges on the gear doors before 1961. Color photographs suggest that the slat wells were painted red before the gear-door edges began to be painted red, so if the slats aren't red, then it's likely that the gear-door edges weren't either.

Some other interesting examples:

Note that the A-4 on the left has red slat wells (and you may not be able to see it, but the gear doors are not red-edged) while the one on the right does not. (The airplanes are from two different squadrons; in general, the maintenance officer of a squadron liked to have all of his charges be from the same overhaul batch so they were identical in configuration.)

The slat wells weren't always red (however, this is the only example I've seen).

The speed brake wells (or flap cove for that matter) weren't necessarily red even though the interior of the speed brake was.

One interesting aspect of this requirement is that McDonnell painted crush points red from the beginning, and not just the edges of the landing gear door but the whole door.

North American and/or the Navy also appears to have painted the interior of the landing gear doors on some FJ-3 and FJ-4 Furys red.

* Rick Morgan reminded me of a reason, maybe the reason, for all that red: "When I was in TRACOM we were told that the red edges to door was so that you could quickly see if one wasn’t seated properly in flight, usually while checking a wingee with an unsafe ‘up’ indication. The red under the slats also helped determine that they were deploying properly as you slowed down; an A-3 with a stuck slat could be catastrophic;  you really had to pay attention to them while slowing down... Likewise red speed brakes were great indication that they were moving (always exciting when lead forgot to warn you while descending a section in weather) Never thought over-all red was a good idea; it made hydraulic leaks harder to see."

Marking Anomaly

This a TBM assigned to Philippine Sea in the late 1940s.

Take a closer look at the underside of the left wing.

This is how the markings on the underside of the left wing should have been oriented at the time. (A large NAVY marking was subsequently located there, with a smaller unit code and aircraft number located under the wing somewhere.)

I haven't seen any other examples of this particular presentation except on Brit airplanes. Note that if  someone buzzes you, it's a lot easier to read his unit code and aircraft number after he goes overhead if the airplane is marked this way although I'm sure that's not the reason...

Elliot doesn't mention this convention so my guess is that it was a layout error by a novice squadron painter.

Fitting In

Many of these posts are the result of questions from acquaintances or asked online. If the question is interesting, often the answer seems worthy of saving by this means.

In this case, the question was from Larry McCarley, who is working on a 1/48th model of the Skyhawk. He was having trouble with the width of the side consoles and the distance between them relative to the actual aircraft.

The answer was basic and similar to the problem of putting an exact scale reciprocating engine in the cowl of a plastic model: the actual thickness of the fuselage skin is far thinner than can be replicated in a plastic model and engines are closely cowled. In the case of the A4D, the fuselage skin was a relatively heavy 0.10" aluminum sheet.* In 1/48 scale, that's .002," or half the thickness of a sheet of 20-lb copier paper. Given that there was some insulation on the interior of the sidewalls (it's cold outside at 35,000 feet), the 1/48-scale sidewall would have to be literally paper thin if the width of the consoles and ejection seat are to be to scale. Good luck with that.

Larry reports that the actual interior width of the Hasegawa 1/48 A-4 kit between the sidewalls is about 35.6 scale inches, meaning that the width of the consoles and the ejection seat has to be reduced by a total of almost three scale inches, a bit less than 10%. (I'm surprised that it isn't more; I would have guessed that the wall thickness of a 1/48 scale kit was about 1/16 inch, meaning the interior width would have been a scale six inches narrower than the real thing.)

I suspect that this is the problem with aftermarket resin cockpits that require extensive grinding on the cockpit sidewalls to install and undersized ejection seats in some kits. You have to fudge or cheat the width of the interior components to get them in the width available. Hasegawa fudged in part by narrowing the forward console.

The A4D cockpit is particularly challenging in this regard. Heinemann was obsessed with minimizing the Skyhawk's weight and wider was heavier. As a result, the Douglas-designed ejection seat was just wide enough for the average pilot's bottom and the consoles (at the front) just wide enough for the installation of the standard-width control panel. (Douglas probably avoided having to replace its seat in the A4D with one from Martin-Baker simply because of the narrowness of the installation.)

*As one of several weight-saving Skyhawk innovations, Heinemann combined a flak-mitigation design with the basic airframe structure. The AD Skyraider had proved to be susceptible to relatively light antiaircraft damage in the early days of the Korean War. An external "armor" (deflector plate) kit was quickly developed that could be added over critical areas including the side of the cockpit.

In the A4D, the weight penalty of the thicker than structurally necessary skin was somewhat mitigated by the fact that it did not require the use of longitudinal stringers in that area, which also minimized the width of the fuselage.

A4D-1 Rudder Development

One of the most notable differentiators between the A4D-1 and -2 is the rudder. On the -1, it had a smooth exterior surface. On the -2, longitudinal stiffening ribs were riveted to either side of a central panel. The change was made because of rudder flutter that had been experienced early on in A4D-1 flight test. Recently, someone inquired as to how the A4D-1 was released for service with a rudder flutter problem and by chance, someone else asked about a feature on the A4D-1 rudder that I hadn't paid  attention to before. It turns out that the feature was the answer to the question.

In passing, I also noted another rudder detail change from the XA4D-1 to the production A4D-1. The X and early production Skyhawks had a rudder trim tab with an actuating rod on the left side of the rudder.

The original solution to the rudder flutter problem was the addition of a dash pot-type damper just above the center rudder hinge. Note that the trim tab is still part of the design.

The dash pot allowed the pilot to move the rudder but "stiffened" it at high frequencies to preclude flutter.

The rudder trim tab was deleted on A4D-1s delivered to operational squadrons.

When the rudder flutter problem was solved aerodynamically with the so-called tadpole rudder, the damper was deleted.

Note the addition of a ground-adjustable trim tab.

NEW Airfix 1/72 A-4B/4P Modeling Notes

27 October 2025: This is a replacement link for an excellent build article on the 2011 Airfix A-4B/P kit: https://www.tapatalk.com/groups/airfixtributeforum/airfix-1-72-douglas-a4b-4p-skyhawk-a03029-t47356.html

26 October 2025: For the beginning of a build article of the original Airfix A4D kit, click HERE 

21 June 2014: I added a comment on the detail on the upper fuselage between the canopy and the dorsal fin here: http://tailspintopics.blogspot.com/2014/06/more-modeling-notes-on-172nd-airfix-4b.html

21 November 2012: I added some detail on the landing gear sponson features here: http://tailspintopics.blogspot.com/2012/11/the-dirty-underside-of-a4d.html

15 September 2012: I forget that you might have gotten here by a web search or reference link and so might not have scrolled through the blog and seen the other Skyhawk stuff:

Nose Shape: http://tailspintopics.blogspot.com/2012/11/airfix-172-a4d-2-overall-size-and-shape.html

A4D-1 Rudder http://tailspintopics.blogspot.com/2012/08/a4d-1-rudder-development.html

Fuel Tanks http://tailspintopics.blogspot.com/2012/07/douglas-low-drag-external-fuel-tanks.html

1/48th Cockpit http://tailspintopics.blogspot.com/2012/09/fitting-in.html

7 August 2012: One point that I might not have made clear is that the external configuration of the J65-powered Skyhawks changed over time as product improvements were incorporated at overhaul. Airframe change dates aren't much help because it might take a few years before an airplane went into overhaul after a modification was approved. The A4D-1 in the New England Air Museum is an example.

Note that it still has the fuselage vortex generators that were removed from some A4D-1s.

3 August 2012: Thanks to Peter Collins, we now know the difference between the early and late oil vent on the right side of the J65-powered A4Ds.

 Note that the round vent is located in the center of an oval panel that matches the one on the early vent.

I also added some information on the early and late wing tip lights.

2 August 2012: Added detail on differences
1 August 2012: I don't know if it's represented on the kit, but the A4D-1 and -2 had a small hole in the nose for avionics cooling:

Note: Because this is a picture of an A4D-1, there is no angle of attack sensor on the fuselage. There was however, a box on the upper right side of the landing gear strut containing lenses and a light to provide angle of attack information to the LSO at night. Scroll down to the bottom of the page for a picture and link.

The Scooter is one of my favorite airplanes so I was particularly pleased when Airfix issued a new kit of it in my scale.

 Picture from the Hannants web site

I haven't gotten it yet so this is a work in progress based on the posts of others. I also am not an expert on the A-4P so I'll confine myself to discussing the U.S. Navy Skyhawks.

For one of the build posts, see Drewe Manton's web site http://drewemanton.com/models/2012-07-27-a4b-800s/a4b-build-800s/vma324_a4b.html

Airfix based its new Skyhawk kit (it also produced a much simpler and not very accurate A4D-1 kit decades ago) on the A-4B displayed on Intrepid, which is now a floating museum docked on the Hudson at New York City. It therefore represents one that has been through rework and modification several times.

For example, here are some differences annotated on a picture published by "Ajay" as part of his build post in 72nd Aircraft:

Note that the scoop on the aft fuselage was not on early A4D-1s or 2s. It appears to have been added during A4D-2N production over one of the existing vents to improve cooling in the aft fuselage. It appears to have been retrofitted to A-4As and Bs beginning in 1965 on a quick review of pictures in Steve Ginters Naval Fighters Number Fifty. Also see Naval Fighters Number Forty-Nine for many, many photographs and illustration of the A-4A and B.

The kit also has the radar altimeter fairing under the left wing tip. This was added during A4D-2N production and retrofitted to some A4D-2s, including the one on the Intrepid. However, it may have to be removed depending on the specific A4D-2 being represented. For this and some other details on the differences between the A4D-2 (A-4B) and A4D-2N (A-4C), see http://tailspintopics.blogspot.com/2010/07/a4d-skyhawk.html. Note that the A4D-2N (A-4C) had a nine-inch longer nose to accommodate a terrain avoidance radar.

The major omission is the oil vent port on the left side of the fuselage. It was a significant feature in no small part because of the oil streak emanating from it.

This vent was originally  rectangular with rounded corners on the A4D-1 and -2 as shown above. At some point, at least on the -2 and possibly in conjunction with the addition of the air scoop over the small rectangular flush intake on the side of the fuselage, it became round. The feature is present on the  Skyhawk displayed on Intrepid that Airfix used as a reference but wasn't included on the kit.

Cropped from Peter Roan picture HERE

The missing upper rectangular openings just aft of the fuselage break (these provided access to the bolts that attached the aft fuselage to the mid fuselage) could be represented with paint or a decal for simplicity of construction...

I don't know whether the blade antenna aft of the canopy in the kit and on the Intrepid Skyhawk is representative of a later version or not, but the early antenna was clearly different:

 
The kit has a representation of a later version of the Douglas ejection seat, the main external difference being the addition of a vertical slot/channel in the headrest for the "head knocker" used to arm the later seat. It had better ejection performance and was introduced with the A4D-2N (A-4C) in early 1960. It was retrofitted to A4D-1s and 2s.

This is a very early seat being lifted by Ed Heinemann himself to demonstrate its light weight:

Note that the ejection handle should be housed slightly and stick straight out, not be slightly extended and drooped.  For this display, the seat is missing the seat cushion, backpack parachute, seat belt, and shoulder harness as shown in the Escapac seat picture above. The shoulder harness straps (to which the parachute straps were attached) are very short because they were to be connected by the pilot to fittings on the pilot's torso harness, not the seat belt. The early seat can be created from the kit seat by filling in the head-knocker slot (there should still be a depression in the headrest that accommodates the back of the pilot's helmet) and cutting back the sides.

Another picture of the early headrest:

Note: The blade antenna normally mounted behind the canopy was installed under the nose of this aircraft.

The external wing tanks may be undersized and according to the pictures, have a constant cross section where they should be bulged. See http://tailspintopics.blogspot.com/2012/07/douglas-low-drag-external-fuel-tanks.html for more on the Skyhawk tanks, sources for accurate tanks, and a link to Douglas external tanks drawings.

There were early and later main landing gear wheel hubs. Some A-4s had the early hubs through at least through 1970. The kit reportedly has the early hubs.

Another feature on the early Skyhawks that changed over time was the wingtip light. On the A4D-1 and at least the early A4D-2s, they were flush and inboard of the tip. The early formation and position lights were the same color. The formation lights were subsequently deleted and the position lights relocated to the edge of the wing tip: the aft light was a conventional filament one with a colored lens when dim lights were desired and the forward one was a colored gas-discharge light illuminated on the Bright setting. The "Fuselage" lights (there was also one on top of the fuselage; it was subsequently replaced by a red anticollision light with another added to the bottom of the left main landing gear fairing) were used for signaling at night.

The major changes to convert the kit to an A4D-1 are easy: remove the inflight refueling probe and fuselage fairing and modify the rudder (or replace it) so it has a flat surface rather than external stiffeners. The hard part is the different configuration of the vortex generators. For that and some more detail on the A4D-1, see http://tailspintopics.blogspot.com/2011/01/a4d-1-vortex-generators.html

The nose landing gear was slightly different:

 Note: Early A4D-2s might have the early angle of attack indicator and fork or the early angle of attack indicator and the later fork.

For a description of the early angle of attack indication to the LSO, see http://thanlont.blogspot.com/2012/04/night-carrier-landings-in-beginning.html

Douglas Low-Drag External Fuel Tanks Redux

I provided dimensioned drawings of the 150, 300, and 400-gallon Douglas low-drag external tanks here: http://tailspintopics.blogspot.com/2011/07/douglas-low-drag-external-fuel-tanks.html

The tanks and fins were standardized but the number and location of the fins varied with the specific location on a particular type.

The 150-gallon tank was common on the A4D-1 and early A4D-2s.

Because the tanks were very similar in shape, you have to look carefully to see which one is installed. In the case of the A4D, the clues are a somewhat smaller diameter relative to the airframe and more obviously, how far the tank extends behind the wing trailing edge and to a lesser degree, ahead of the wing leading edge.

Here is an example of a single 400-gallon tank on an A-4 and one with two 300-gallon tanks. Note that the 300-gallon tanks do not have fins, which is not unusual, but the forward location of the national insignia on an A-4E is.

I've seen questions about which kits have accurate external tanks so I did a quick survey of some of the 1/72 kits in my stash, comparing their 300-gallon tanks to the drawing. In rough order of acceptability:

Esci A-4 (A4D): Excellent

Hasegawa A-1 (AD): Almost perfect. Rounding the nose a bit provides almost exact length; the fins are a bit small but not objectionably so.

Tamiya F4D: Very slightly oversized, rounding the nose would be appropriate.

Airfix F4D: Very slightly oversized.

Airfix S-3: Basic size and shape okay; the fins need to be cut down. (The basic shape of the airframe is also better than the Hasegawa kit, e.g. the engine nacelles aren't circular.)

Hasegawa EA-6B: Basic tank okay but fins slightly undersized.

Fujimi A-6: Length okay but diameter a bit undersized and too tapered; fins good.

Hasegawa S-3: Too short by about 13" and forward edge of fin angled downward too sharply.

Fujimi A-7: Too short by about 31" and terrible fins

Airfix AD: Somewhat undersized (too tapered/conical) and fins too small.

Hasegawa A-4: Definitely undersized; could be sectioned to create the 150-gallon tank.

Matchbox F3D: 150-gallon size but forward part of tank is too tapered, conical.

Hasegawa F9F-8: 150-gallon size but too small in maximum diameter; taper down in diameter from mid section both forward and aft is too conical; and the fins are not correct.

Alex provided some additional notes on tanks from other kits:

Fujimi A-4E/F kit # F24: L = 77.5mm, D = 8.7mm.
Overall shape appears to be correct.

Hasegawa AV-8B kit # D19: L = 85mm, D = 10.4mm.
Definitely oversized.

Academy OV-10A kit # 1665: L = 54mm, D = 7mm.
Too small even for a 150-gallon tank.

Sword F3D-2 kit # 72072, 300-gallon tank: L = 77.5mm, D = 8.5mm.
Overall shape appears to be correct.

Sword F3D-2 kit # 72072, 150-gallon tank: L = 61mm, D = 7.3mm.
Apparently undersized.

For some aftermarket options, see http://tailspintopics.blogspot.com/2013/08/things-under-wings-douglas-low-drag.html

Comments, additions, and corrections welcome.