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General control line discussion => Open Forum => Topic started by: Richard Koehler on November 15, 2013, 06:06:23 PM
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Does anyone know where the Fancy Pants is supposed to balance? Thanks for looking.
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I just checked my copy of the Brodak plans and it shows it 2-3/8" back from the L/E.
You'll still want to trim the model to your individual preference though. y1
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Thanks for the information.
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I see this so often, but yet it is not a dumb question either. I was taught early in my building of flying model control line planes was that 25% of the average chord was a good starting point. I wonder if people actually read the instructions and look at the plans that come with their kits. Even scratch building a plane from plans, the designer usually shows a starting. Now Richard I'm not saying you didn't read the plans or the instruction book. You say the plane is the Fancy Pants. Is this the one from RSM Dist.? If so Eric sometimes does forget to include instruction sequences. Also he is a great guy to talk to when he is not busy. I'm not going to mention the items he left out in a kit I built of his. Have built several of them and this one kit slipped by somehow. He did make good thought. Another plane I need to reproduce with different power system. H^^
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I was taught early in my building of flying model control line planes was that 25% of the average chord was a good starting point. H^^
Bad advice here Doc.
Todays modern stunt ships, with large stab/elevators, can withstand a center of gravity at 25% or so. But if some poor beginner tries to fly a Skyray, Flite Streak or Ringmaster with the CG that far back, he'll likely bring the model home in a bag.
Even classic ships such as Noblers, Ares, Smoothies and such, have small tail feathers (as compared to modern ships) will typically fly with the CG at about 20%.
Start with the CG a bit forward than what you think it should be and work your way back. It is always better to start off nose heavy than tail heavy.
Larry, Buttafucco Stunt Team
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Bad advice here Doc.
Today's modern stunt ships, with large stab/elevators, can withstand a center of gravity at 25% or so. But if some poor beginner tries to fly a Skyray, Flite Streak or Ringmaster with the CG that far back, he'll likely bring the model home in a bag.
Even classic ships such as Noblers, Ares, Smoothies and such, have small tail feathers (as compared to modern ships) will typically fly with the CG at about 20%.
Start with the CG a bit forward than what you think it should be and work your way back. It is always better to start off nose heavy than tail heavy.
Larry, Buttafucco Stunt Team
Well,, if we are talking about generalities here, then let's put a different perspective on this CG thing.
A good safe place to put the CG on a flapless airplane is 20% of the Mean Aerodynamic Chord. Since many of the older flapless airplanes have straight wings, just go with the 20% location and you have it. Or, if there is a tapered wing involved, unless there is an extreme amount of taper, not normally seen in CL stunt ships, the average chord will be very near the mean aerodynamic chord and the 20% location on the average chord will suffice.
For "typical" flapped designs, the 25% location of the mean aerodynamic chord will be a safe starting place. Again, unless there is a lot of taper not normally seen on typical CL stunt ships, the 25% location on the average chord will work.
Now, for some of the more modern designs, like with pipes with 25% horizontal tails or bigger, there are some that have the CG well back of the 25% average chord, but this is in the realm of more advanced designs and fliers. For some electrics, the matter of the CG that some top fliers are using becomes a whole different subject well beyond the scope of this discussion.
Keith
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15% on a stock Twister worked fine for me.
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Bad advice here Doc.
Todays modern stunt ships, with large stab/elevators, can withstand a center of gravity at 25% or so. But if some poor beginner tries to fly a Skyray, Flite Streak or Ringmaster with the CG that far back, he'll likely bring the model home in a bag.
Even classic ships such as Noblers, Ares, Smoothies and such, have small tail feathers (as compared to modern ships) will typically fly with the CG at about 20%.
Excellent! My work is done.
Brett
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Excellent! My work is done.
Brett
Ha, Who do you think I learned all of this good stuff from.
I have learned over the years, who to listen to and who not to listen to.
Larry, Buttafucco Stunt Team
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All I know from experience is that a nose heavy plane will fly without too much trouble other than it might take more control. But, a tail heavy plane will be hard to fly level and land. I have on in the shop that just proved my theory in the shop that will not fly again because of the damage.
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25% will be tail heavy, a flapless model may or may not even be flyable at this setting. Starting around 18% will put you in the "close to right" trim area and the airplane should be easy to fly assuming no major alignment or warp problems exist.
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25% will be tail heavy, a flapless model may or may not even be flyable at this setting.
Well, to be fair, it does depend on how fast you can run.
15% is a really good starting place for many of these sorts of models.
Brett