Fr3aK Zone - Page 35 - RC Groups
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Mar 26, 2012, 12:05 AM
Registered User
iwokeupwithgills's Avatar
Analytical solutions with the level of anisotropy found in composite layups would be difficult to arrive at, much less reproduce during fabrication. Perhaps you could get some experimental (modal) results of different layups using a laser-doppler velocimeter? The modal shop also rents accelerometers and modal hammers if you wanted to do a simple modal test to get FRFs.

I submit that perhaps there is some coupling between the boom's fundamental modal frequency and the aeroelastic or vortex shedding behavior of the stab that could be exploited.
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Mar 26, 2012, 12:30 AM
Jim C
ShadowFalken's Avatar
42 Tom. nice lateral thinking.
Mar 26, 2012, 08:32 AM
Father of Fr3aK, DLG Pilot
tom43004's Avatar
I'm not sure how consistent my materials and processes are yet, but it looks like there may be some real benefit here. Obviously I will be testing more.

I pulled three more sets of tails this past weekend and all were under 13.5 grams. So much of that process has changed that I think I should post a new video

I have also been playing with the seaming method on my fuses and have peeled about five to ten minutes from that layup. Every little bit helps.
Mar 26, 2012, 11:47 AM
Team Crunch Brothers
Tom, have you tried to validate the launch difference with a different thrower? It is possible that you effectively tuned your fuse to your specific throwing style, but that may not help someone that launches with a slightly different style? Maybe they need that kick point a little further out, or closer in...

Mar 26, 2012, 12:13 PM
Father of Fr3aK, DLG Pilot
tom43004's Avatar
Yes, it's very possible Lex. Could we be buying our DLG fuses with a "tour stiff 100" or a "85 flex" rating in the future?

Mar 26, 2012, 12:30 PM
Just fly it!
wyowindworks's Avatar
Tom, is it possible that the way that canopy was taped on was different. I know that when I had some people testing my fuse they found out that the way the canopy was positioned and sealed would effect launch height. I don't think that it was effecting the actual launch height but rather how the altimeter was taking a reading. Fluctuations of 20' could be attained by just fiddling with the canopy seal.

BTW, in no way am I trying to discredit your findings. You could very well be onto something very significant. I just don't trust those pesky altimeters.
Mar 26, 2012, 01:39 PM
Father of Fr3aK, DLG Pilot
tom43004's Avatar
I don't trust them either, but no... The canopies were the same.
Mar 26, 2012, 02:26 PM
Throw it like you hate it
RCPC's Avatar
Awesome empiricism! Where did the 6gr weight savings happen with the new fuse? If the weight savings came from the extremities, could this lead to a reduction in the amplitude of the yaw excursions on launch, leading to increased launch height? Also, does moving the kick point farther aft effectively make the boom stiffer by shifting the bend profile? Some static deflection tests with a load at the tail would be interesting to evaluate as well. I like your pursuit of "free" launch height. Can I have some as well?
Mar 26, 2012, 03:17 PM
Father of Fr3aK, DLG Pilot
tom43004's Avatar
Extremeties are a pinch lighter Paul. I took some material from the boom in general and replaced it in certain places and with layers.
Apr 05, 2012, 10:39 PM
Registered User
NorCal Hobbies's Avatar
Tick tock. tick tock.
Apr 09, 2012, 09:22 AM
Father of Fr3aK, DLG Pilot
tom43004's Avatar
Different tail shape for testing with the same airfoil, slightly thinned, and about 8% larger...
Apr 09, 2012, 10:34 AM
Jeff Carr
I like that. Should help in the launch

Apr 11, 2012, 09:51 PM
registered user
can you send a set of those tails to Australia ?? PM was full
Apr 11, 2012, 11:15 PM
rcgeorge's Avatar
Tom that looks great
Apr 12, 2012, 12:38 PM
Registered User
NCDLG's Avatar
Tom, amazing work as usual. I like the look of the new tail... go big!


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