Sunday, October 13, 2013

Gyro ... text explanation ...

After my  posts about this topic, I received lots of questions/comments regarding the reason why I agree now that Gyro are prohibited. Problem of this controversy and debate is that most of people are mixing their personal wish and are failing to analyze the text itself. They don't read the text as it is, they don't analyze the wording. A good example is when you ask the question: Do you think that the current rules allow or ban the use of gyros ? The answer is "I'M AGAINST GYROS !" which is obviously not answering the question. "Yes maybe but I don't care, I'm against" they repeat! This will not make things to progress for sure !

So let's your opinion aside, and please have a factual look at the current rules.First observation: Model definition differs between F3B, F3J and F3F

F3B

5.3.1.1.  Definition of a Radio Controlled Glider
Model aircraft which is not provided with a propulsion device and in which lift is generated by aerodynamic forces acting on surfaces remaining fixed in flight, except control surfaces. Model aircraft with variable geometry or area must comply with the specification when the surfaces are in maximum and minimum extended mode. The model aircraft must be controlled by the competitor on the ground using radio control. Any variation of geometry or area must be actuated at distance by radio control.

F3J

5.6.1.1.  Definition of a Radio Controlled Glider
A model aircraft which is not provided with a propulsion device and in which lift is generated by aerodynamic forces acting on surfaces remaining fixed. Model aircraft with variable geometry or area must comply with the specification when the surfaces are in maximum and minimum extended mode. The model aircraft must be controlled by the competitor on the ground using radio control. Any variation of geometry or area must be actuated at distance by radio.

F3F

5.8.2.  Characteristics of Radio Controlled Slope Gliders
Maximum surface area (St)............................... 150 dm2
Maximum flying mass . ....................................... 5 kg
Loading on St ..................................................... between 12 and 75 g/dm2
Minimum radius of fuselage nose 7.5 mm in all orientations (see F3B nose definition for measuring technique).

The radio shall be able to operate simultaneously with other equipment at the normally used spacing in the allocated R/C bands (i.e. 35 MHz : 10 kHz). The competitor may use three models in the contest. The competitor may combine the parts of the models between the rounds provided the resulting model used for flight conforms to the rules and that the parts have been checked before the start of the contest. Addition of ballast (which must be located internally in the model) and/or change  of angles of setting are allowed. Variation of geometry or area is allowed only if it is actuated at distance by radio control.

For F3B and F3J the important sentence is:

"The model aircraft must be controlled by the competitor on the ground using radio control. Any variation of geometry or area must be actuated at distance by radio control."

First point: Control surfaces movement are not part of the geometry/area variation as per aeronautics definition (source aeronautics engineers). In fact this sentence  has been written to cover the possibility to heavily change the glider properties (wingspan, section, root chord) between duration and speed task that requires totally different plane in theory. A good exemple is Ralf Decker's Tele-F


Second point: model aircraft must be controlled by the competitor on the ground using radio control

A gyro is not controlling the model aircraft, it is stabilizing it. If you don't pilot your glider, he will simply crash. With or without gyro, the pilot is the only person controlling the plane. The "hole" comes from the fact that the rules refers to the model, not to the control surfaces. Gyro controls the surface, not the aircraft. So this sentence is not clear enough and allows the use of Gyro. A Simple change could be: "model aircraft control surfaces must be controlled by the competitor on the ground using radio control".

Now, F3F glider definition is even less precise as the sentence "model aircraft must be controlled by the competitor on the ground using radio control" doesn't appear which would mean that something/somebody else than the pilot could control/pilot the plane !!!

So based only on the rules 5.3.1.1., 5.6.1.1., 5.8.2. I'm considering that the gyro is allowed, and for F3F, we could even consider to install an autopilot (OK, stupid idea I recognize!).

Now there is another general section in the FAI rules that defines categories:

1.3.3. Category F3 - Radio Controlled Flight

This is a flight during which the model aircraft is maneuvered by control surface(s) in attitude, direction and altitude by the flier on the ground using radio control.

For me this sentence is much clearer, because it says that control surfaces must be actuated by the flier on the ground using a radio control. This make a big difference as any on-board devices acting on the control surfaces in the back of the pilot is therefore prohibited, which is the case of a gyro.

This is because of this sentence that I changed my mind, and now agree that Gyro is forbidden in the current rules. However, I still think that it would be good that the CIAM write a recommendation/statement to make things even clearer.

Update: another rule in the Section 4C says it all as the model aircraft must be in direct control of the flier. this rule cannot be more explicit.




Now, the debate to know if it must be authorize in the future is another question. To be honest, I have a mixed feeling about that subject as they are good arguments on both sides.

For the moment, I will test a gyro in sport flying to see if they are real benefits on a sailplane at the slope. I'm considering to use it in the future on a aerobatic glider. I will keep you updated

1 comment:

  1. "If you don't pilot your glider, he will simply crash. With or without gyro, the pilot is the only person controlling the plane."

    Hi Pierre,
    this is definitely serious mistake and faulty argument. If you will switch off your Tx with gyro in active mode, glider will fly without any problems thanks to permanent gyro activity trying to react to any force disballancing your model in any of 3D axis until your on board batteries will die. Just try it on workbench and then in the air, as well as me. It is gyro is able to control your model without any pilot input. Seems to me people have no clue about possibilities of these devices.

    BR
    Roman

    ReplyDelete

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