Design > Stunt design
Ted's Tucker Special Ballast Experiment
Brett Buck:
--- Quote from: Gerald Arana on September 28, 2013, 07:27:36 PM ---BINGO! That is exactly what I was trying to express in the other (DELETED) thread. y1
Brett, Not being an AE I like that squared & cubed thing.... I have experienced it in my past (Glider Competitons) The bigger ships fly better for that application.
Will we see you in Napa on the 6th?]
--- End quote ---
Perhaps, judging as usual, but likely not flying.
Brett
Brett Buck:
--- Quote from: Phil Krankowski on September 28, 2013, 07:26:40 PM ---When you increase the size of an airframe, unless you are building with solid wood, the final density of the skinned and finished airplane will be lower than a smaller ship. This is a large function of built up construction containing mostly air volume.
A large plane that is too light may benefit from ballast at the CG...although how much in CL? I know RC gliders, particularly slope gliders, will benefit from ballast under windy conditions.
The general rule of lighter is better probably still holds.
Phil
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The fraction of "air/balsa" is constant if you scale everything up (including the wood thicknesses).
The Tucker experiment definitively showed that lighter was not always better. That doesn't mean that heavier is always better, either. It depends on a multiplicity of things far beyond the overall mass or wing loading.
Brett
Russell Shaffer:
Is there an article on this experiment available? I don't find anything with a Stunt Hanger search.
Phil Krankowski:
--- Quote from: Brett Buck on September 29, 2013, 12:09:29 AM --- The fraction of "air/balsa" is constant if you scale everything up (including the wood thicknesses).
The Tucker experiment definitively showed that lighter was not always better. That doesn't mean that heavier is always better, either. It depends on a multiplicity of things far beyond the overall mass or wing loading.
Brett
--- End quote ---
No. It's not. If you have a round hole, and increase the diameter by 2x, it has 4x the area but only 2x the perimeter.
If the material sizes are increased by the same percentage as the increase of overall scale the density is still going to be reduced.
Phil
Kim Mortimore:
A general reminder here to no one in particular---if we get into controversy, please play nice to avoid having this thread get bounced. Thanks in advance.
--- Quote from: Brett Buck on September 28, 2013, 02:12:54 PM ---......I have seen a few somewhat larger airplanes that suffered greatly from being built too light and too powerful which made the trimming beyond the capabilities of the pilot to diagnose and correct.
Brett
--- End quote ---
Brett,
Do these planes all tend to have the same problems, or are the problems all over the place?
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