What’s the difference between a chandelle and a hammerhead stall?
A chandelle is basically a high-bank turn, performed while ascending at a high rate, the going back down.
A hammer head is a much more vertical maneuver, putting much more stress on the aircraft.
There’s a good description of both on Wikipedia’s aerobatic maneuver page.
Yeah, that’s actually where my question comes from as I can’t seem to grok the difference in the Wikipedia descriptions. I know that a hammerhead uses rudder, but they both look the same to me. I’m wondering, not just how their performed, but how they look different to a spectator.
They look very different. A chandelle is basically a climbing turn. The plane starts in level flight, banks, then climbs while turning. In a hammerhead, the plane enters a vertical climb, loses airspeed, and appears to stop in midair (hence the name stall turn). At the top of the climb the plane yaws left or right to point vertically towards the ground. It gathers airspeed, then straightens out to level flight.
Here’s a chandelle: http://www.nasascale.org/maneuvers/chandelle_turn.htm
Here’s a hammerhead: http://www.geistware.com/rcmodeling/aerobatics/maneuvers/stall_turn.htm. Note that maneuver is performed in a vertical plane, unlike the chandelle.
In a Chandel, the aircraft is basically flown through the entire manuever, with plenty of airspeed over the top…though this could still be well below the “stall speed” for level flight.
In the hamerhead, it stops flying at the top. While refered to as a “stall” this is inaccurate by the aerodynamic definition. In vertical flight, the wings are unloaded, the vertical parts of the manuever requires them to produce no lift, in such a condition, stalling is impossible.
When the aircraft stops at the top (actually just before) , rudder is applied to yaw the aircraft. The rudder is effective at zero speed, as it is in the prop wash. Gliders have to fudge and kick the rudder while there is still some airspeed to initiate the yaw.
OK here’s full disclosure:
I fly (high performance) model gliders. We fly at steep slopes where wind is perpendicular to the slope, generating “slope lift”. OK. We often do maneuvers that we call “half pipes” or “pumps”, often with planes that have only Aileron and Elevator controls. The idea is very much life a skate/snowboarding halfpipe. From level flight, we pull into a maximum climb (often very close to verticle). Near the apex of the climb (airspeed approaching zero), a very slight aileron input is given, causing the plane to essentially pivots around the “lowered” wing, hanging in the air. Opposite aileron is given to straighten the plane out as it dives. Slowly pull up and do the same thing up the other side. If timed and executed well, the plane will gain height (and speed) with each pump.
I’ve always considered these to be hammerhead stall turns, but was recently told that they’re actually Chandelles or wing-overs since a true hammerhead requires rudder and power. While I don’t necessarily dispute the definition, I can’t see how they’d look any different to a spectator.