Ornithopter Photo's & Drawings #2

[wmueller10]

Rather than post the same pictures again, here is a link to the original thread (some very nice aircraft are posted there).
http://www.rcgroups.com/forums/showthread.php?t=324577

Here's a 1889 aircraft patented by R.J. Spalding. Pic inset 2 shows the contraption being supported by a balloon, so the designer must of intended the articulated wings as a method of propulsion and maneuvering only' (for his Flying Machine). If you were to build an articulated, feathered wing today, it would look similar to this design,,, hat's off to Mr. Spalding.
(I didn't bother to read the patent pages on this one but you can). http://patft.uspto.gov/netacgi/nph-P...&RS=PN/398,984

Pic 3, Here's a great shot of a bird flying and articulated wings in action. As you can see, thou not so obvious, the port side wings' area is slightly reduced in the photo. Almost certainly the bird has incountered a port side wind and has adjusted his wings for course correction.

[wmueller10]

The inventor of this 1877 ornithopter design, Murrel, claimed that his contraption actually flew.
Picture 1-2 shows what's left of his 'washboard wing' concept. A flapper valve type wing set-up, where the valves open on upstroke and close on down stroke, to where some kind of lifting bias would be achieved.
Pic 3, is part of his now well known patent of the ornithopter.

In reality, although this aircraft never flew, Murrel had the fortitude to go on and build his dream and should be considered a stepping stone toward ornithopter flight.

http://www.kids-online.net/learn/murrell/murrell.html

[wmueller10]

I recently encountered a computer problem where most of my ornithopter website data was destroyed. I have a few photo's for which I was able to save but who these people are, is a mystery.

Pic 1, a 1900 circa human-powered orni. Pic 2-3, a russian engineer and his wonderful models, the pictures were dated 1978 and 1980. The last one kind of reminds me of a giant airborne jelly fish,,, I wonder if it ever flew
Enjoy the pics. Willi

[Aerosapiensman]

Mr. Mueller, I invite you to visit my website: aerosapiens.com. I feel that by the comments you have made that you can handle my invention in theory. It is 18 feet in span and about 5 feet in chord. Check out my site then get back to me about what you see. Especially, the subtle movements. I have viewed some 1800's patents too. I did not see the one you post. Very interesting. the man attempts to use his whole body to power the contraption. Thank you. Sincerely, David a Moore.

[wmueller10]

Originally Posted by Aerosapiensman

Mr. Mueller, I invite you to visit my website: aerosapiens.com. I feel that by the comments you have made that you can handle my invention in theory. It is 18 feet in span and about 5 feet in chord. Check out my site then get back to me about what you see. Especially, the subtle movements. I have viewed some 1800's patents too. I did not see the one you post. Very interesting. the man attempts to use his whole body to power the contraption. Thank you. Sincerely, David a Moore.

Wow, your the second birdman/towerjumper that's contacted me this month, I wish both of you all the best success with your flying machines.

David reviewing your website, it looks to me as your planning to build a flapping winged aircraft (fletcher) powered by a pilots arm movements.
My opinion is; it won't work. No matter what physical arm strength you can manage, it's still not enough. At best, you may be able to hold a 30 foot wing span out straight for a few seconds, but to flap as a bird or bat is out of the question.

Another problem I see, the design of your aircraft is wrong as well. Few people realize, a ornithopter's C of G is constantly moving around.
Pic 1, shows the CG of an ornithopter while the wings are near the wing-up' position is farther forward than when in a wing-down' position. As Pic 2-3 shows, the same applies to your aircraft. While your wings are in a dihedral postion, your CG is correct, your craft is flying level as intended. As the wings move into a anhedral postion (while flapping), your craft becomes tail heavy and will go unstable, causing you to fall out of the air.

Of course this is just my opinion and I could be wrong about it, but without a long tail to stabilize your aircraft, you need to keep flying over water until you have these things ironed out.
And last, I'm impressed with your teams efforts so far. Welcome to the forum and Good luck, Willi

http://www.aerosapiens.net/

Added info 6-28-05
I was fortunate enough to find this photo backing a CG shift as I see it. Based on tail position alone, would suggest these birds are compensating for a CG shift.

[aerohydro]

Hello

Recently I stumbled upon an interesting online catalog of 18th and 19th century aeronautical prints, known at the Tissandier Collection. Click here for the website, with the index being accessed at this spot. Apart from being available online, the Tissandier Collection has also been packaged up onto a CD-Rom, and is sold commercially under the title "Early History of Ballooning". A search on eBay should yield a few listings for it.

Though mostly about ballooning, the collection does contain a few prints of ornithopters and the like. Below are a couple of a snipped images from one such print, this one concerning two ornithopters designed by J J Bourcart in 1866. The whole print can be accessed by pointing your mouse here. It's quite an amazing print, I think.

Cheers,
Paul

[mscott]

Willi,
I am confused as to why the C of M should shift fore and aft as you show it. Is this to do with the powering pilot's leg movements?
Paul's pictures of Bourcart's biplane show the same kind of counter-rocking as Tupolov's machine. Are there other examples of this principle?

Murray.

[mscott]

Willi,
I reckon the Egret's apparent asymmetry may be simply because of the forshortening of the port wing due to anhedral and the view angle.
Egrets are very photogenic.. there is a similar photo on the cover of David Alexander's book "Nature's Flyers" , a fascinating read.
Murray.

[wmueller10]

Originally Posted by mscott

Willi,
I am confused as to why the C of M should shift fore and aft as you show it. Is this to do with the powering pilot's leg movements?
Paul's pictures of Bourcart's biplane show the same kind of counter-rocking as Tupolov's machine. Are there other examples of this principle?
Murray.

Originally Posted by mscott

Willi,
I reckon the Egret's apparent asymmetry may be simply because of the forshortening of the port wing due to anhedral and the view angle.
Egrets are very photogenic.. there is a similar photo on the cover of David Alexander's book "Nature's Flyers" , a fascinating read.
Murray.

Originally Posted by mscott

Willi,
I had understood that the term "C of G" was simply an imprecise variant of the proper physical term "C of M". You imply some other meaning.. could you explain it?
I can see that thrust will create a pitching moment, nose-down or nose-up depending on the instantaneous dihedral or anhedral, but over a complete flapping cycle it will average out to about the same pitch moment as a fixed wing set at the mean dihedral. A bit of cyclic pitching won't bother either birds or onithopters.

Murray, the C of M will stay about the same, no matter what position the wings are in.

[ As long as your ornithopter (craft) is not flying, you can check the CM or CG of the craft because the terms roughly have the same meaning. However when the craft is flying, the term 'CG' should only' be used because the Flight Glide Path is influenced by wing position. The C of M is the static balance point of an ornithopter and the C of G is the balance point of an ornithopter to "fly" a level glide path, and thou the CM/CG of the craft (physical balance once set) does not move (this applies to 90 degree wing sweep orni's only), the lifting properties of the wing will change because of the varying wing position angles, causing a CG shift as argued. ]

This is my opinion and I apologize for the confusion.

P#8, Yes, at first glance I thought the same thing. Only after looking a bit closer, thou not so obvious, it appears the birds LE port wing tip is angled back about 5 degrees. Also I interpret the feathers as being closer together (port side) reducing the wing area, favoring a left turn into the crosswind.

[mscott]

Willi,
I had understood that the term "C of G" was simply an imprecise variant of the proper physical term "C of M". You imply some other meaning.. could you explain it?

I can see that thrust will create a pitching moment, nose-down or nose-up depending on the instantaneous dihedral or anhedral, but over a complete flapping cycle it will average out to about the same pitch moment as a fixed wing set at the mean dihedral. A bit of cyclic pitching won't bother either birds or onithopters.