Trey Carroll wrote:
ZRX61 wrote:
I thought I was going to witness a crash at an airshow yesterday. Hammerhead stall in Bearcat?? WTF??
Let's hear about that.

We haven't heard anything yet on a Bearcat incident, but I will state flatly that doing a Hammerhead on Level 1 waivers in a prop fighter would NOT be in any routine I would condone.
I've done them in the 51 with altitude but never even thought of doing one in a show routine. The Bear, considering it's power and propeller size could even be more problems in this scenario than the 51, although both have the same issues to some extent.
The problem with a low altitude initiated HH in these airplanes is a complex one, and it gets exceedingly worse as the aircraft flies the up line. As you lose energy you get slipstream force, torque, and gyroscopic precession all acting on the airframe in varying degrees with increasing rates. In a Bearcat you can have your hands full of airplane in a heartbeat as things deteriorate nearing your apex point.
Slowing on the up line, your slipstream tightens on you becoming more and more powerful tending to slew the aircraft right which in turn drops the left wing. Now torque comes into the equation and wants to roll you left. You're correcting these forces with right rudder and right aileron if you have a ball centered up line.
At the apex things can get downright interesting on you. As the energy bleed comes back to your rotation point and you apply inside rudder to initiate the pivot, you're now faced with gyroscopic precession as that HUGE prop disk rotates up front. That wants to pull you over on your back while torque wants to roll you left. You apply forward stick to counter the precess and right aileron for the torque. The speed difference between the rotating wings causes a lift asymmetric requiring right aileron to kill the lift countering that left roll tendency.
If you're beginning to get the picture that Hammer Heading something as powerful as a Bear from a low altitude initiated up line just might not be the maneuver of choice for the prudent and well advised, my work here today has been well spent.
It is possible to reduce power as you fly the up line and make the pivot powered back which is indeed an option for doing a HH in a prop fighter but even that's not a good idea coming off a Level 1 initiation.
Bad JuJu in these airplanes.
Hoover, as good as he is, torqued off his high apex in a 51 at Transpo in 72 at Dulles. Being Hoover he saved it but anyone else might have had a really bad day.
Anyway, my read on Hammerheads off the deck in Bearcats FWIW.
Very glad this one had a happy ending because the rest of the weekend was bad news enough for a lifetime.
Dudley Henriques