15 October 2026: Updated with more information (see comment)
David Aungst became aware of the difference in the tips of the stock A-4 ailerons and elevators and those of the Blue Angels A-4F Super Foxes and took these pictures of the four-ship display (one did have the Blue Angels mod) suspended overhead in an atrium of the National Naval Aviation Museum at Pensacola, Florida to illustrate it.
Note that the aft outer edge of both the aileron and elevator of the Blue Angels Skyhawks come to a sharp corner rather than being rounded (I overlaid an outline of the stock aileron and elevator on the Blue Angels' so I'm pretty sure that there was no increase in span of either as a result).
The difference seems small but apparently it made a notable enough difference in roll rate and pitch control power to be worth it.
In response to the comment below, I attempted to compare the prototype aileron and elevator tips to the later production ones. Unfortunately, I haven't yet found good pictures for the purpose. It does appear in some that the prototype tips were more pointed, particularly the elevators, but not in the best picture I could find.
However, this picture of an A4D-1 suggests that the tips were sharper at some point thereafter:
Other, better known external changes to the Blue Angels A-4F Skyhawk included the bulged intakes and longer tailpipe that were associated with the Super Fox configuration (see https://tailspintopics.blogspot.com/2011/02/super-fox.html and the illustration below), the removal of the cannons, a housing for the boarding ladder extending from the left cannon bay, the bolted up slats (they were individually actuated aerodynamically so might not extend or retract at the same time, decreasing roll control precision), and the addition of a drag parachute housing under the aft fuselage.
The boarding ladder was very narrow and collapsed like a parallelogram to fit in its housing for flights to and from display venues.
While I have never seen it referenced and certainly cannot prove it, I think the rounded trailing edges on Scooters evolved once the airplane made it to squadron strength and deployed to carriers where deck space was at a premium I suspect early Skyhawks were designed with sharp corners on their surfaces - which were right at head height- that proved through use to be a bump hazard to people on the flight deck. This resulted in the softening of the corners a bit after a number of guys got divots in their craniums while working around the airplanes. Note that the very pointed corners on the main landing gear doors evolved the same way over time. I offer this based on my dad's experience with the very sharp corners on the horizontals on a Vigilante. As he dismounted the squadron bicycle on the ramp at NAS Sanford many years ago, he turned and took the corner of the stab in his right eye. They managed to save it but he was hospitalized at NAS Jax for at least a week. The same kinds of things likely happened with Skyhawks. I think it likely the Blues were happy to trade the added ground safety margin of rounded tips for the crisper handing and looks of the original design - no one made the team by being sloppy or careless in the air or on ground.
ReplyDeleteHow do you do, Tommy.
ReplyDeleteI recently found your great blogs (too late!), filled with incomparably valuable information.
About the tip geometries of the aileron and elevator of the Blues Skyhawks, I noticed it when I built a Hasegawa 1/32 kit 10 years ago. But I skipped to check the geometry of the rudder at that time. I noticed later that it seems not to be, probably, in the same shape of aileron and elevator but rounded. I don't know the reason, of course.