RCU Forums - The DEATH SPIRAL MANEUVER - save your 2 channel plane

THE DEATH SPIRAL MANEUVER
To Save Your 2 Channel Plane
by Ed Anderson
aeajr on the forums

This article is about a maneuver that every 2 channel pilot should learn.
It could save your plane!

The issue we are trying to address is that there is no way to force them
down. Without an elevator you can not induce a controlled dive as you can
with an elevator. If you get down wind you can easily lose the plane.
Likewise, if you get the plane up in a thermal, you can have a wonderful
time riding the lift, but you may have trouble getting the plane out of the
thermal by just gliding out or by using the motor.

There is ONE way to force these planes to come down, that is by using the
death spiral. Used properly it may save your plane. Used incorrectly it can
destroy it.

POWERED GLIDERS

Two channel rudder/throttle planes can be very easy to fly and lots of fun
for a new flyer. They are basically motor launched gliders. You power them
up and climb, then you power off and let it glide down. If you hold partial
throttle, you can maintain height for a while, but you come down by gliding.

The HobbyZone Firebird series is an example of this but there are many
others. The shape and style of the tail is not important to this discussion
so this has nothing specifically to do with V tail, cross tail or any other
shaped tail system. It may be easier to initiate with a V tail but I think
all tail configurations can do this. Give it a try.

Planes that fly by differential thrust, that is by varying the speed of two
motors, can not reliably perform this maneuver that I am aware of. They do
not have the banking ability that the R/T planes have. If someone can force
a differential thrust plane in to a death spiral on a consistent basis,
please add you comments. I have tried it with the HobbyZone Outlaw and a
couple of the FlyZone planes without success.

I will use the Firebird Commander as the example in this discussion but it
really applies to all 2 channel R/T planes. They are lots of fun to fly. I
have enjoyed flying other people's Commanders and similar planes. I just
don't recommend them because I prefer to have elevator control as part of
the control system. BTW, the HobbyZone Aerobirds can be flown exactly the
same way you fly a Commander, even though they have an elevator. You
don't have to use the elevator to fly the plane. It works fine without it,
but the elevator make the death spiral maneuver unnecessary.

THE DEATH SPIRAL MANEUVER

Be sure you are VERY high the first time you try this. Be sure the wind is
fairly calm, say less than 3 mph. If you have some kind of anti-crash
technology, ACT, turn off as this is what ACT tries to prevent. New pilots
tend to hold the rudder over too long and accidentally go into a death
spiral. Then they freeze there and the plane crashes. The ACT feature is
trying to keep new pilots from accidentally going into a death spiral. We
are going to do it intentionally.

Get the plane high and up wind from you. Turn the motor off and get it into
a smooth glide, preferably going across your field of vision. This is just
so you can see what is happening. Make sure you are over open space,
preferably long grass. If you fail to recover you don't want to drop it
into the woods or on top of someone.

Normally you use the rudder for brief times, a second or two, to initiate a
turn. However if you hold that rudder full over for a long time, say 4-5
seconds, the turn will get tighter and tighter and the plane will get on a
steeper and steeper angle till the wing tip is up at about a 60 degree or
higher angle.

At this angle, the wing has very little lift and the plane will go into a
death spiral and start to spiral dive down very fast. If you keep the rudder
over it will dive tighter and faster. If you center the stick, the plane
will usually pull out of the spiral, but not always, and it takes a LOT of
altitude to come out of the spiral on its own.

After you get it down to a reasonable height, you give it OPPOSITE rudder to
pull it out of the death spiral. That is, if you started the death spiral by
holding the rudder hard left, you take it out of the spiral by giving it
hard right rudder. The direction the plane is facing at the moment does not
matter so don't worry about that. You are trying to stop the spiral, not
worry about which way it is going. After you get it out of the spiral you
can worry about where you want it to go.

Remember, the motor is off the entire time. Do NOT turn it on until the
plane has fully recovered to level flight or you may not be able to recover
at all. The motor will not help here so leave it off!

You will need at least 50 feet of altitude to get it out of the spiral if it
is really in tight, so make sure you have at least 100 feet, say double tree
height, when you start to pull it out, but higher is better!

I suggest you do this only for short dives at first. Get it into the spiral
then use opposite rudder to take it out right away. No more than 2 seconds
of dive. You will get a feel for how fast it will come down. Try this a
few times. Get used to forcing it in and out of the spiral. Practice this
very high to give yourself lots of time to get out.

This is the ONLY way I know of to force the plane down quickly. If it gets
caught in a thermal you can have a great time riding the lift, but you may
not be able to get out of the thermal by just turning out or by using the
motor, but try them first as they put a lot less stress on the plane. If
you can't get out, you need to use the death spiral.

If it gets down wind and you can't get it back, pick your spot and spiral it
in. You will crash but at least you will have a chance to find it if you
pick the spot.

SUMMARY

I don't recommend two channel electric planes, but if you are going to fly
one you need to lean this maneuver in order to save your plane from booming
thermals or down wind situations. I know the V tail planes can do this and
believe you can force any plane with a rudder into a death spiral.

Also note that this puts a LOT of stress on the wing. If you have a crease
in your wing from a bad landing, this may cause that crease to fold. But it
is better than losing the plane.