Wednesday, March 12, 2008

Lessons : Death Spiral

Here I got Flying Lesson From, i'm sure this lesson will help you Guys.....

Don't let the name intimidate you, the death spiral maneuver needent spell the end for your pride and joy as the death spiral is fairly basic in design and execution. The majority of the maneuver is basically just a prolonged elevator flip, it's the knife edge falling part that can raise the blood pressure a little!

The setup for this maneuver is your basic 3D setup (Idle Up Two) (-10 to +10 pitch). Try to maintain around 1750 - 1800 RPM on the head. Gyro in heading hold.

Before you attempt this maneuver you should be comfortable with the following:
1. Fast Forward Flight.
2. Nose in.
3. Inverted hovering (both tail in and nose in).
4. Inverted circuits.
5. Quick hand-eye co-ordination :).

Please make sure you are comfortable with the above before you try this, nothing is worse than watching someone try and fly outside their ability and screwup and not have the ability to catch it!

The Death Spiral is made up of a number of different actions. You start at a good altitude (for your first one start very high!) then:
- Quarter aileron flip to knife edge. It is important that the heli is right on it's rotor tip and falling straight down. If it is not, your death spiral will not be straight.
- Apply some forward or back elevator while in the falling knife edge position, the heli should now be 'spiraling' straight down.
- After about two to three flips (depending on your flip rate) I recommend bailing out. Do this by applying the OPPOSITE aileron to what you applied to start the flip. This way you will come out with the heli the right way up.
- Continue to practise this maneuver but continue to increase the number of elevator flips that you do before bailing out.

Mix it up:
Once you have become comfortable with pulling out of the maneuver upright, try adding a little extra something in there by pulling out inverted, backwards etc.

Try doing a 45 degree Death Spiral by adding negative pitch while nose in, then positive pitch while tail in.

Also try compensating for wind conditions by adding in the appropriate pitch controls to ensure the heli falls straight.

Also, once you've got yourself sorted here, start trying to transition the helicopter from vertical falling flight to sideways horizontal flight while flipping. For example, while doing forward elevator flips, had in a little right aileron and a little negative pitch when the heli is nose in to you, then once it gets tail into you, add in a little left aileron and a little positive pitch. Be careful not to 'overpitch' the controls else you'll bog the engine, loose headspeed, make lots of noise etc and the result won't be great. If you do it correctly the heli should end up flying sideways while still flipping.

Points to watch while doing this maneuver include:
- During the spiral part of the maneuver, ensure that you have zero pitch on the blades as the helicopter is falling, otherwise the heli won't fall straight.
- Make sure the heli enters the maneuver on the knife edge falling perpendicular to the ground other wise the maneuver will be 'crooked'

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