"Flying the Wallis Autogyro"

Editorial note:  The following bit of information has been passed on to us by Colin Hutchison, who received it from Paul Mathews  (Finland)  ....and we caution that while this is excellent information concerning the flying of the Wallis (Benson/pusher type) model autogyro,  this is not the technique we would recommend for tractor type models.    The techniques suggested were strictly written in regard to the (tricycle gear) Wallis, and may possibly apply to other similar models such as the (tri-gear) Kalt Robin, but would not necessarily apply to the majority of common model autogyros, which are predominently tail wheeled models.



MICRO-MOLD  WALLIS  AUTOGYRO  PILOT  NOTES

General:

Single rotor autogyros present a new challenge to the R/C modeller and certain techniques will need to be mastered to achieve a consistent flying performance.   Previous experience in flying fixed wing models is perhaps more relevant than helicopter flying and I,  with the aid of these notes both types of pilots should find no problem in converting to autogyro flight.

Control Throws::

Swashplate movement should be the maximum possible and is approximately 30 degrees either side of neutral.
Engines:

A good 60 or Schnuerle ported .50 will give the best results.

Fuel Tank:

Do not use silencer pressure unless absolutely necessary.  The system illustrated in Fig. 2 will give a constant engine run irrespective of the amount of fuel in the tank.

Take Off:

DO NOT RELEASE THE UP ELEVATOR,   until the model leaves the ground.

As the wheels are released from the drag of the ground the nose will pitch up.  Correct this with a firm but gentle jab of down elevator,  but don't overdo it or the airspeed may increase too much.  After some practice it is quite possible to do very smooth take-offs even from relatively rough ground without the nose pitching up at all.

(It is very difficult to define precisely the exact sequence of events at take-off but it may help to think of it as being exactly opposite to normal fixed wing procedure- In the case of the gyro the stick is held back for most of the run but then pushed forwards at the point of take off)-

Continue the climb out to a safe height keeping the airspeed as low as possible by using the elevator.   With a good motor fitted this should present no problem but if less power is used then a fair amount of juggling with the elevator will he required to keep the speed above that minimum required for level flight.

Again,  as experience is gained you will be able to do a slalom climb out at a higher airspeed,  but at this stage it is best to err on the too slow side and rely on engine power to get you out of trouble rather than risk the total loss of control that can result from too high a speed.

With the model at a safe height throttle back to tickover,  at the same time pushing the nose forward to level the machine.  ( I f you have made a particularly steep climb out you will probably need full forward stick at this point for about two seconds to stop the model from falling backwards out of the sky.   From this point on it is really just a case of gently  'easing'  the model around the sky at the lowest possible throttle setting-  If in doubt,  throttle back;  if the nose pitches up when the throttle is closed then the previous throttle setting was too high!

Turns & Circuits:

Turns should be initiated with aileron and then held with the rudder with a touch of up elevator as per fixed wing.   Opposite aileron is necessary during anything but the gentlest of turns to prevent the turn tightening up-  There is always a slight tendency to balloon coming out of a turn as the extra g force has caused a temporary increase in rotor r p.m.

When flying in a wind he careful  (a)  NOT TO turn downwind to sharply.
Autogyros don't like negative airspeed and the model will drop like a stone and
(b)
NOT TO increase the airspeed when flying into the wind.   Let the model come on at its own speed.

For the first flight you may find it helpful to have someone standing alongside you to confirm which way the model is flying.   Orientation can be a bit of a problem until you get used to it.

Landing:

The secret here lies entirely in the use of the elevator control:  the throttle is not used at all during the landing.  If this basic technique is always used  (it's not too difficult)  then even engine off landings will present no problem in the future.  The landing run is about six inches in no wind, and zero in any wind at all.

Position the model about 50' downwind and at about 50' altitude.  Close the throttle to tick-over and keep it closed.

Push the nose down  (about 1/2 stick movement is typical),  this is quite safe provided the throttle is closed.   The model should now be descending towards you at an angle of about 45 degrees with the rotor disc more or less horizontal.   You will need to continue to hold the stick forwards to maintain airspeed.  If this is your first attempt you will probably undershoot,  so be prepared to go round again if necessary but remember to apply the elevator in advance of the throttle.  If all is going well continue to 'push' the model down to about 2-3 feet at which altitude level the machine out without letting it "balloon" by releasing the forward pressure and applying up elevator if necessary.   As soon as the forward speed has dropped away to nothing apply full down elevator to level the rotor and the model will settle gently, dropping the last six inches or so vertically.

This is very similar to landing a helicopter engine off but very much easier and with much more leeway for error.  In fact you can drop the last two feet vertically without any damage as long as the elevator is held forward to stop the rotor chopping off the top of the rudder in the ensuing bounce. .

This landing method is an alternative to that used by many other flyers who initiate the landing flare by a quick burst of throttle as in normal fixed wing flying.

The aim is to set up the final stage of the landing such that the model can be made to touch down with  (a)  the throttle fully closed,  (b)  the lowest possible airspeed and  (c)  the elevator stick well forward.

If you do land a bit hard check that the main undercarriage strut has not deformed causing the main wheels to bind,  or you may have trouble with the next take- off .

Normal rolling landings are an extension of this technique but with the throttle set at just a little above tickover and the model more or less flown onto the ground with just a hint of flare before pushing the elevator forward at the point of touchdown.

Landing is much easier in a gentle breeze
(as is take-off.)

Remember that once the speed of the model has dropped below that minimum required for level flight the model will drop whatever you do with the throttle,  so unless you've got at least five feet of altitude don't stop the model unless you intend to land!

Taxing:

DO NOT use the throttle in an attempt to cushion the landing.  You may get away with it for some of the time but more likely you will chop the tail off or strike the ground with the rotor about one landing in three.

The autogyro is much easier to taxi than most fixed wing models and will quite happily taxi cross wind.  Always keep the rotor angled towards the wind.  On rough ground keep full down elevator applied.

I have found that if the fixed nose leg is angled very slightly to the left taxiing turns can be accomplished to the right by opening the throttle and letting the torque from the rotor rev up turn the model.  This works very well on grass but would probably not be quite so successful on concrete.

Basic Landing Rules:

Down elevator at touchdown will prevent tail damage being caused by the rotor if the landing is a bit heavy.

Final Points:

There are three conditions to guard against on take-off and it is important to be able to recognise these conditions should they occur.

Symptom:    Model takes off fairly quickly & rolls to the left.  Usually accompanied by the whole model shaking.

Cause:    Rotor speed too low at point of take-off

Remedy:   Check bearings,  clutch,  coning angle (too high)  and blade incidence.
Check balance also as a rearward CG can allow a premature take-off.

Symptom:

   After a long run the model pitches violently upwards and into the air.

Cause:  Ground speed too high.

Remedy:   Hold more up elevator during the take-off run.

Symptom:   Model staggers about after take-off under full control but will not climb. (This condition is easy to achieve when flying from grass with low power).

Cause:   Airspeed too low.

Remedy:   Gently 'push' the model forward using down elevator and expect some (loss) of height.   At about 5 to 6 m.p.h. the model will start to climb.

rev..1-17-99..jb