A new tractor design

Supermotive

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Try looking up Sorrell Hiperbipe as an example.
Good Stuff. I am currently trying to fit my fuse design into a STOL wing airfoil; and attempting to adjust for fitment. The part that is a little difficult, is I will be tapering the 2 side trusses into each other; with the side trusses eventually meeting within the rudder. Sorrell Hiperbipe seems to keep a wide fuselage all the way to the tail. This tapering in mine may cause me to bleed off some of the downwash as the air hugs the top of the fuselage.
 

Jean Claude

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I piloted gliders C800, Bijave, C 310, airplanes Piper J3 , PA 28, Jodel D117, DR 220, Cessna 150, C
Total Flight Time
About 500 h (FW + ultra light)
A 8.8 x 0.2 m rotor lifting 990 lbs at 100 mph reaches a ratio L / D = 9
No lifting fairing reaches this ratio and therefore it is better to entrust the entire lift to the rotor alone.

If it is a wing of 3 m² wing, then it should not carry more than 200 lbs, otherwise the rrpm will be reduced too much. This means cL < 0.27
While, the cD = cD min + (cL² / π A) = 0.025 with the wall interactions and an span of 4 meter (A = aspect ratio = 5.3) Hence L / D = .27 / 0.025 = 11 for the wing alone

So, the total drag with airframe is improved by less 2%
 
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XXavier

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Madrid, Spain
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ELA R-100 and Magni M24 autogyros
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673 gyro (Jan. 2021)
Downwash?

You're right. The downwash doesn't hit the fuselage of a gyro flying s/l. I enclose a graph of the downwash of a gyro calculated by Jean Claude. I've tilted it 30º so that the relative wind is level with the computer screen...

The downwash has a downwards component with respect to the direction of the relative wind, but not so much that it may hit the fuselage...

ctrum10xjk.jpeg
 
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kolibri282

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I have run a few sample calculations in my rotary wing design program. The aircraft is a Magni M-16, the wing area is 35 sqft and the rotor is unloaded about 30% with the wing lift ( fWN(3) ) being 1320 N. The rrpm reduces from 414 to 343. The rotor X force reduces considerably from 173 N to 24.7 due to a smaller disk angle (7.2° vs 9°) but the wing adds more drag than the reduction in rotor X force. Note that I have not checked whether the wing drag is calculated correctly, I have not considered winged gyros a lot. This shows that, as always in aircraft design, to gain an advantage some really careful design and optimization is necessary. One advantage of a winged gyro is the much broader wheel base you can employ, as can be seen from the nice pic blow.


No wing, thtaN=2.5°
mu 0.149 thtaN/cTs 0.75246 cTs_cr 0.01265 cTs_cr/cTs 0.21821 UvViHov 4.73908
alfaD 8.98° alfaNf 7.68° alfaS 14.53° als -5.55° als_th -5.61°
oM 43.376[1/s] oMR 178.5[m/s] oMR 585.6[ft/s] n 414.2 [1/min]
fMR(1) -173.94 fMR(2) -10.24 fMR(3) -4098.89
fWN(1) -0.00 fWN(2) 0.00 fWN(3) -0.00


with wing thtaN = 2.5°
mu 0.181 thtaN/cTs 0.76291 cTs_cr 0.01265 cTs_cr/cTs 0.22124 UvViHov 5.78568
alfaD 7.17° alfaNf 5.61° alfaS 14.45° als -7.27° als_th -7.35°
oM 35.927[1/s] oMR 147.8[m/s] oMR 485.0[ft/s] n 343.1 nmmt 199.8 [1/min]
fMR(1) -24.77 fMR(2) -10.24 fMR(3) -2773.39
fWN(1) -314.62 fWN(2) 0.00 fWN(3) -1319.70



Pa-18_advertisement_31.jpg
 
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Alan_Cheatham

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Have you done a full structural analysis before beginning construction or are you just hoping for the best?

The primary load bearing truss structure should have no curved tubing, all tubes should be straight.

Also, be aware that if you build the fuselage side trusses to dimensions you have pulled off the two-dimensional side view the fuselage will end up shorter than designed by the time you bend the tail to a taper, this will be more so for a wider side-by-side design. Consideration must be given to tail taper and "stretching" the tube layout to compensate.
 

kolibri282

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Quote: Consideration must be given to tail taper and "stretching" the tube layout to compensate. /Quote
That was the reason why I had proposed to use a CAD program for the final design, these programs allow to automatically calculate the correct length from a 3D model
 

JEFF TIPTON

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Try this site for ideas.

Douglas fir would be a good material.

 

Jean Claude

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Centre FRANCE
Aircraft
I piloted gliders C800, Bijave, C 310, airplanes Piper J3 , PA 28, Jodel D117, DR 220, Cessna 150, C
Total Flight Time
About 500 h (FW + ultra light)
When the airframe is subject to the efforts, it stretches some tubes and compresses others. For this long tubes, the buckling limit is reach far before the elastic limit. Thus I wonder why want a high elastic limit that does not bring anything.
 

Alan_Cheatham

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