Aircraft Customization and Development Community

    This thread is intended for discussions of issues and exchanges of experiences and ideas related to customization and/or development of aircraft in Aerofly RC. I invite all who are interested to comment or share your experiences.

    I have been experimenting with customizations of some of the aerobatic aircraft in the RC9 library via the Edit Aircraft tool. For example, I have started to build a customized SBach 342 that performs like my Pilot RC SBach 36% model (107 inch wingspan) that you can see in my avatar. I have also started to work on a customized Extra 330 that is designed and sized for a 120 cc engine.

    i have come across some perplexing issues I thought to be worthy of discussion within the Aerofly RC community. Here is an example:

    The Extra 330 Standard model in the RC9 library is described as Roland Matt's TOC model. It has some parameters revealed in the Edit Model window that I find somewhat strange. I assume that the "size" of the model is the wingspan, which is 3 meters. The wingspan and the 17.2 kg mass are consistent with the 40+% airplane size category that TOC pilots typically use. Airplanes this big typically use 150 cc and larger gas engines.

    The engine power vs RPM curve has a maximum of 7.367 kW, which is 9.88 HP. This is the maximum power that Desert Aircraft quotes for their DA 100L. A DA 120 has a maximum power output of 7.6 kW (see https://hfeinternational.com/w…DA120-Data-Sheet-2021.pdf for details.). Yet the airplane behaves as if powered by a larger engine.

    The propellor parameters don’t make sense as given. The radius is 33.717 inches which makes the diameter around 67.4 inches. The pitch is 28.669 inches, which is much larger than the maximum pitch on model aircraft propellors available today. The largest propellor from Mejzlik is a 30x13 3-bladed propellor. Interestingly, if I divide 33.717 x 2 and 28.669 by 2.54 cm/inch, the results are 26.5 diameter and 11.3 pitch. These numbers in inches make somewhat more sense if the propellor is 3-bladed. Are the textbox captions for these parameters in the Edit Aircraft window correct?

    Despite the fact that I am flying manly gliders since many many years, I made the experience model simulators are not at all the tool for developing or adjusting a real model.

    This is true from the beginning with MFS blessedly until latest RC9.

    You can influence flight behaviour, but hardly ever transfer the values needed to a real model.

    EG: at a real 4m competition glider the position of CG is important in millimetre, but in any simulator you have to change almost centimetre to have the same effect.

    The same will be true with power requirements and propeller behaviour.

    So enjoy flying simulator, adjust the model to your need but do not apply the values to reality.

    Jürgen N. Thank you for your comments. This thread is off to a good start.

    What I am trying to do is modify existing aircraft simulations in the RC9 library so that they perform in RC9 like their real versions perform at the flying field. For example, my 10 year old Pilot SBach 342 that is my avatar has a 107 inch wingspan and a DA 100L engine with MTW canisters. I want to create a simulation of this airplane in RC9 that behaves like the real thing by modifying the existing SBach 342 in the RC9 library. To do this, I believe I need to do the following:

    1. Change the size i.e. wingspan from 3 meters to 2.7 meters.

    2. Change the mass to 12.5 kg.

    3. Change the engine power vs RPM curve so that it has a maximum output power of 9.8 hp or 7.3 kW at 7500 RPM.

    4. Change the propellor parameters to 27 inch diameter or 13.5 inch radius and the pitch to 10 inches.

    5. Increase the CG distance by around 4 cm so that the airplane maintains a horizontal trajectory with zero elevator deflection.

    With these changes I have gotten to a simulated airplane that behaves more like the real airplane than did the unmodified version. The Pilot SBach has a thick wing airfoil that causes the real airplane to fly more slowly at full power than the simulated airplane. I have not yet figured out how to adjust the wing airfoil parameters in the Edit Aircraft window.