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My Live KATU Flight 370 broadcast presenation

Monday, March 12, 2007

MENTOR - Aerobatics: Hammerhead Turns

I think the Hammerhead turn is the best aerobatic maneuver. It has it all; diving zooming, acceleration, deceleration, near weightlessness, slow flight, turns, sky and good views of the ground!

Start at altitude, of course! Push over briskly for a smooth quick dive. Maybe take your G load down to +.5g on the pushover and stabilize into your descent. Don’t forget left rudder, enough for the Look out to maintain positioning and ground-track, you have a moment before needing to look at the airspeed indicator again, since it takes a moment to build to 145 or so, your hammerhead turn entry speed. At your entry speed, start a smooth quick steady pullback. Maybe about +1.5 to +2.0g. Remember your rudders; just as a steep dive or pitch down requires left rudder, you’ll need right rudder when pitching up! As you pitch above the horizon and keep going up, switch your primary view 90 degrees left or right.

You are watching for the wing to get to 90 degrees perpendicular to the horizon. Perpendicular wings to the horizon mean you are going straight up, which is the goal. This is where it gets a little tricky and needs a little practice. You want to get to straight up before you run out of airspeed, and I don’t mean airspeed dropping so low you might stall, I mean airspeed dropping so low you don’t have enough ruder authority to make a crisp pivot turn at the top. The dangers here are mushing out the bottom of the turn and falling into a sloppy spiral, or a spin entry, or a tailside, which while fun and exhilarating can be damaging to your otherwise sturdy aerobatic steed when the tail slide slams the elevators back against their hinges. But we are not here to talk about the dangers, we are here to talk about how fun it is when you do it right!

As you near the top, it gets quiet. The whoosh of air slows and the controls get softer, just like they do when you slow down when landing. You are almost ready for the turn! JUST before too little airspeed remains, kick full rudder, either direction. The remaining momentum will putt-putt you over the top, and ideally you’ll reach the apex of the turn with one wing straight down and the other straight up just as you peak at your highest altitude for the maneuver. You can’t forget aileron! The plane will generate more lift on the up-wing, and so will need more countering aileron. If you pivot the turn to the right, you’ll need right aileron, making the top left aileron go ‘down’ holding the wing straight in the turn. If you forget aileron going over the top you’ll definitely come out on an un-intended heading, and possibly end up flipping over on your back which quickly turns into a dive recovery.

As soon as that top wing passes straight up and the nose starts dropping below the horizon things are going to speed up quickly! Controls will start getting that solid feel back, and you’ll need to back off the aileron towards neutral and start coming in with left rudder for your dive. If all went nicely, you’ll be on the reciprocal heading you had when you entered the maneuver, and you’ll be in a nice clean dive. You only have one thing to decide; throttle back and ease back into level flight, or leave it at full throttle and do it all over again! It’s nice to have such choices.

onward & upward! ~ rfb

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