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

11 July 2016: It turns out that I didn't do this topic justice. For a much more through and well illustrated discussion, see http://airfixtributeforum.myfastforum.org/viewtopic.php?f=3&t=47356

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. (See http://myaviation.net/?pid=02024117.) 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 here: http://z15.invisionfree.com/72nd_Aircraft/index.php?showtopic=2286&st=0

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 (http://www.ginterbooks.com/NAVAL/NF50.htm). Also see Naval Fighters Number Forty-Nine (http://www.ginterbooks.com/NAVAL/NF49.htm) 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.