by Tommy H. Thomason

Friday, June 1, 2018

AD-4W Skyraider

I thought I'd already done a post on the AD-4W but if I did, I can't find it. So here's a primer based on information that I provided to a kit maker.

Basic AD notes:

1. The vertical fin and rudder were angled three degrees to the left with an an asymmetric airfoil that lifted to the right. See http://tailspintopics.blogspot.com/2017/08/relying-on-museum-pieces-for-accuracy.html

2. The powerplant section including cowl flaps was angled down by three degrees.

The AD-4W was similar to the AD-4 with the following notable exceptions:

1. Addition of a large belly-mounted radome

2. Landing Gear

The landing gear reverted to the early AD configuration with no doors covering the retracted wheel. The wheel retracted into a round opening on the underside of the wing aft of the main wing spar. The retraction mechanism folded into a truncated triangular opening forward of the spar similar to this AD-5Q.
Jim Robbins Photo

The catapult hooks were relocated from under the inboard wing to the main landing gear strut. This resulted in a different forward-facing landing gear door.

Left main landing gear shown. The forward facing door was sometimes removed for flight.

3. Wing

A "stall strip" was added to the leading edge of the right wing only, roughly the maximum width of the well for the gear retraction mechanism.

A fixed slat was added to the leading edge of the outboard wing panels.
(Underside of right wing. Note pitot.)

The outboard wing panel stores pylons and all guns were deleted although the openings for the attach points for the pylons appear to have been retained. Early type AD pylons were retained on the inner wing panels to carry external fuel tanks.

4. The oil cooler outlet was relocated from the belly to each side of the fuselage just aft of the cowl flaps.



5. Addition of a fairing aft of a new sliding cockpit canopy to house electronic-component cooling system (the windscreen remained the same).

Note the inlet and outlet providing air for a radiator at the aft end of the turtle back.

6. Addition of crew-compartment doors on each side of the mid fuselage. Note that the U.S. Navy AD-4W door's window was not bulged like the Brit airplane's.

7. The "armor" plate added during AD-4 production on the side and belly of the forward fuselage was not installed.

8. Auxiliary vertical fins were added to the horizontal stabilizer to restore directional stability lost with the addition of the radome. Both were angled to left by three degrees like the vertical fin.
 (Before you whinge about the dubiousness of photo interpretation, which would normally be appropriate, this fin orientation is stated in the Douglas AD-4W maintenance manual, with a caution that they are not therefore interchangeable.)

9. The dive brakes were deleted. Unlike the AD-5W, the lower speed brake well was covered over.

10. An HF antenna was added to the top of the vertical fin.

Unfortunately, even Douglas Skyraider drawings are not necessarily accurate in shape. This is a work in process using Douglas drawings attempting to define the location and shape of the crew door and the electronics turtle back.
All published AD-4W drawings are at best a close approximation of the unique details.

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