# Would planes be better if they were more like birds?

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#### henryk

##### Well-Known Member
University of Toronto had the same problems with pitching and heaving when trying to takeoff.
=24 HP +turbo jet engine !

iff compare
with Toporovs 0.5 HP "engine" ???

or 20 HP ISTINA 4-wings orni ?

#### jedi

##### Well-Known Member
Henryk,

Because it is apparent we we have language limitations I would like to ask if you understand the physics of my comment on the landing gear issues.

Also are you aware of the Kasper Aerodynamics posts on the Secret Projects Website?

Kasper wing and trapped vortices

You may need to go to Secret Projects Forum in order to log in.

#### henryk

##### Well-Known Member
Kasper Aerodynamics
-in practice=auer KASPERWING (160 kg /16.7 m^2) can fly horisontally with 5 m/s speed...

Cl =???

#### jedi

##### Well-Known Member
"
henryk
ACCESS: Restricted

" ???
My data tag on Secret Projects shows Access Restricted also but I am still able to access the sight and post comments. I think it is saying I am not an administrator.

#### jedi

##### Well-Known Member
-in practice=auer KASPERWING (160 kg /16.7 m^2) can fly horisontally with 5 m/s speed...

Cl =???
How was that measured? Was it corrected for wind? What was the pilot weight, empty weight and gross weight?

In other words how valid is that data point?

5 m/s = 11.8 mph

Good weight and wing area data but missing density. What was the density altitude. temperature and pressure? If possible calculate Cl with your best guess of the numbers.

I would love to see a video of the Kasper Wing flying along side a person jogging with a wind sock or flag in the background.

160 Kg = 352 pounds

352 pound gross weight minus 254 pound airframe weight = 98 pound pilot!

Most if not all flying Kasper Wing aircraft in the USA are pushing the 254 pound FAR 103 limit.

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#### henryk

##### Well-Known Member
My data tag on Secret Projects
-I was registered,but now I have problem with new registration...

=reg.completed !

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#### henryk

##### Well-Known Member
I would love to see a video of the Kasper Wing flying along side a person jogging with a wind sock or flag in the background.
I understand Yours opinion=12 mph is hard to measure=

1=typical K-W flow/speed meter,bottom of scale
2=Pitot tube on long arm
3=ANEMOMETER (0.1-30 m/s)
4 + bicycle,paralel on airfield road...

(pic.14)

#### henryk

##### Well-Known Member
352 pound gross weight minus 254 pound airframe weight = 98 pound pilot!
=auer GREEN K-W= 75 kg empty weight, wing alone=25 kg (with kingpost),
drive (G25) circa 20 kg.

=85 kg=Pilot (Wojtek) + fuel...

#### jedi

##### Well-Known Member
=auer GREEN K-W= 75 kg empty weight, wing alone=25 kg (with kingpost),
drive (G25) circa 20 kg.

=85 kg=Pilot (Wojtek) + fuel...
Thanks!

#### henryk

##### Well-Known Member
Sure you might get some efficiency gains
=f.e. ConterRotating Differential gear =ONLY ! circa 30 % more Specific Thrust...

#### henryk

##### Well-Known Member
if were talking about a totally different propulsion system like flapping wings then this opens up a whole new category of flying machines and new possibilities.
=experimentally achived Specific Thrust of simple,rectengular fan was 1900 N/ HP
( 263 kG/ kW) !!!

-close solution in VOLERIAN company,but NO theoretical base...

#### nestofdragons

##### Well-Known Member
This is a super video to watch when trying to figure out how wingtip feathers work for birds. It is a 360° video. You can turn to see wingtip, nose or tail. Super handy! sadly not all wingtip feathers visible due to "elbow" in wing.

#### WINGITIS

##### Well-Known Member
This is a super video to watch when trying to figure out how wingtip feathers work for birds. It is a 360° video. You can turn to see wingtip, nose or tail. Super handy! sadly not all wingtip feathers visible due to "elbow" in wing.
BRILLIANT, good find, THANKS

#### DennisK

##### Member
My feather making method may never be able to do nice flexible wingtips like that. Even with the same number of carbon fibers, the stiffness is very sensitive to how the quill is shaped, due to the fact that stiffness is proportional to cube of height but only linear with width. My current molds are concave, so the quill shape is entirely formed by hand as it's laid in after the vane. One idea I tried was to reverse the mold so it has a trough for the quill and then the vane is laid on top. But it turns out precisely filling the trough is not easy to do either, especially with foam core quills.

The loosely connected barbs of real feathers also make them much more flexible than my continuous fiberglass surface. Mine can't flex at all in the side-to-side (in-plane) direction. They can flex up and down some, but the profile curvature becomes tighter as it flexes up, and then the whole thing can snap to an inside-out condition (fortunately they snap back right-side-out on their own when released).

With highly emarginated feathers, and especially if you make the profile nearly flat in the emarginated area, you can get good up-and-down flexibility. Then it's just a matter of precisely controlling the quill shape. I think this portion of the quill could be done in solid carbon even at human scale without becoming too heavy, so then it would only be a matter of trial-and-error to figure out the exact number and length of carbon tow strands to precisely fill the trough on each mold. The foam core portion of the quill back before the emargination would still be inconsistent, but as long as it's too stiff to flex significantly, it will probably function ok.

But even then, you have to figure out what is the right stiffness to be targeting in the first place Perhaps it would be possible to measure the stiffness of the natural reference feathers in some way, and come up with a formula for the quill dimensions to give the same stiffness in carbon, and then extrapolate to the larger size.

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#### henryk

##### Well-Known Member
Is this a mass spring frequency or a flutter frequency?
=dr Sorokodums investigation=all big feathers have equall specific resonance freguency...=26 Hz.

"-The kinematics characteristics of a body of fishes, feathers of birds, wings insects at oscillations (are revealed unknown earlier to science of law). "

from=

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#### REVAN

##### Well-Known Member
Could we have a pic from above and beneath and maybe an STL?
I've been busy working on other things lately, but thought about Owlet again today. I thought it a shame that I wasn't doing anything with it, and recalled that someone had at one point expressed an interest in an stl for it. Why not? Maybe someone else can find something interesting to do with this.

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#### REVAN

##### Well-Known Member
For those without CAD, I put Owlet in GrabCAD. They have a 3D viewer that you can use to see and rotate the model.