Hi, Im very new to this thread. I had seen the posted plan for the Freebird, built it, and, it flys! My 5y/o boy(and wife) got the biggest kick out of it. It took a bit of work to trim for longest smoothest flight, but I managed about 5-7 seconds , maybe a second more with the glide. I noticed late, that the wings "buzz" more than flap.
Does anybody have any idea where to find more free plans, rubber power or other wise. Im thinking I may even try a motor powered freeflight Ornithopter.
has anyone ever scaled up the Freebird?
thanks,
Mark
Greenwood, Indiana

Ok here are some plans I’ve found over the years.

The first link has plans for 5 ornithopters, scroll down to the bottom of the page.
http://www.ornithopter.org/indoor.shtml

This plan is from the October 1935 issue of Model Airplane News.
http://www.theplanpage.com/Months/2105/flapper.htm

This is a link to a thread that has a pdf. file with 4 interesting plans.
http://www.ornithopter.org/forum/showthread.php?t=34

The Spencer Orniplane http://www.ornithopter.org/orniplane.shtml

You can find some drawings on Patricia’s site. It has the drawings of her Behemoth 4,
And John Mack’s “full size” dragonflys.
http://www.ornithopter-pilot.com/Orn...27s_Forum.html

3 plans are available on Yohei Takatani site. Click on the picture to view the plan.
http://homepage1.nifty.com/akatombo/e-product.html
There used to be plans on this site for the dragonfly 1 as well, I can’t seem to find it though. I know it can be found somewhere. I actuialy built one of these, it did fly, but my version came in overweight, still have it.

There are more plans out there. I can picture one or two more clearly in my mind but can’t remember where in the web they are.

I’m sure Willi will have some links to add.

WOW, THANKS!!! I didnt expect so much. Guess I wont have to bother you guys for awhile. Anyone convert any of these to electric freeflight??
Mark

I don’t know if anyone has converted any of these over to electric, but I have heard of freebird electric R/C Conversions.

Speaking of R/C ornithopters here is a link to the Cui Cui Plans
http://www.rcgroups.com/gallery/show...sort=1&cat=500

And the English version of the text from the construction article, in MS Word format.
I was going to convert these to PDF but I think that would just make them bigger.

I will continue to post other plans here as I find them. I hope others will consider doing the same.

Zach

Thanks so much Zach. I'll be looking over these links and plans tomorrow at work. I thought that Freebird might be a good one to try freeflight electric, it has such a small "stroke", prolly wouldnt burden a motor too much. I am wanting to try one with more of a flapping motion than the kinda "buzz" that the freebird has. Not looking to "RC" any yet, just try to understand them more.
Please, if you or anybody else in and out of here find or have anything, please ppost here, Ill check back often.
Mark

Hi Mark,

The Freebird wings should flap through about a 60 degree angle! Based on your description, it sounds like you have the crank radius too small. It should be at least 1/4 inch and can be up to 3/8 inches. You should get much longer flights when you make this change.

Some people have scaled up the Freebird. It will need a much thicker rubber band (more strands of rubber) as you increase the size. You can't simply double the number of strands of rubber when you double the size.

If you need more help with the crank you can e-mail me at nathan at ornithopter dot org.

Nathan’s right, when you double the size of an aircraft you must increase the power by a factor of 4.
A few years back I designed a Ornithopter with a 21” WS that I called the ZXO-3 (Zach’s Experimental Ornithopter version 3). Anyhow it flew so well I decided to scale it up 50% which gave me an ornithopter with a 31.5” WS. It clocked flights at well over a minute. I flipped through some old notes and found that I had powered it with 3 loops of 3/16” rubber.

When you scale up a design make sure the structure of the aircraft can handle the extra load. I didn’t make my wing spars strong enough and they eventually snapped causing the energy stored in the large rubber band to be released all at once, and if you look up the definition of an explosion that pretty much fits the bill. It ended up falling out of the sky in about four pieces, very entertaining for everyone watching.
I recommend using brass tubing for the crank instead of instead of aluminum, epoxy the tubing well in place and use a basswood block to attach it to the motor stick instead of a balsa one. Also use a glass bearing instead of the plastic one listed on the Freebird plans.
Make sure the glass bearing can stand the compression caused by the rubber band, (I had a cheep one shatter).

In short make it strong but keep it light, which is pretty much the rule of thumb for anything intended to fly.

Hope this helps,
Zach

Peck Polymers sells ball thrust bearings that are used in large rubber powered airplanes. You would use this in combination with one of their nylon bushings which are flanged so they can't go anywhere. The ball bearing would greatly reduce the friction. By the way, even though glass lasts longer than plastic, it also has a higher coefficient of friction and is hard enough to wear away at your brass or aluminum tube. All Ornithopter Zone kits, starting in a few weeks, will have Teflon and brass bearing surfaces for reduced friction and long life.

Sounds like that would work much better. I just built that one with what I had laying around and haven’t built any other large ones since. Glass bearings will grind away at tubing. I’ve been experimenting with brass washers placed between the glass bearings and aluminum tubing to reduce both friction and wear on the tubing. I have some Teflon washers but haven’t tried them yet.

Zach

The plastic bead on my Luna** wore through.
I replaced it with a Micro-X Teflon washer backed up with a brass one.
It seems to perform much better after the change.
Pat MacKenzie
** the Luna is sold at Ozone. About the same size as the Freebird but it is a "double flapper" design. Very durable.
I usually give it to kids at indoor meets, and they have only managed to break it once.

What's your source for "micro-x teflon washer"? I would like to compare it with the teflon tubing that I've located.

I bought mine from FAI Model Supply. They offer them as a hop up part for a Science Olympiad plane. Hers a link to the page where they are listed. http://www.faimodelsupply.com/fai-sorcerer.htm

I’m going to experiment using Teflon tubing along with the Teflon washers. It would be nice if someone made Teflon coated glass or plastic bearings. The Teflon bearings I have been able to find were too large for our application and had not been drilled out.

Friction can be a pain,

Zach

Oops, posted twice.

Originally Posted by Chronister

What's your source for "micro-x teflon washer"? I would like to compare it with the teflon tubing that I've located.

I bought them at their booth in Toledo. They (Micro-X) have been in business for a long time, but don't seem to have a web site other than this placeholder
Their address is:
Micro X
PO Box 1063
Lorain, OH 44055
440-282-8354
As Zach pointed out, other suppliers of F/F and indoor stuff probably have them as well.
Pat MacKenzie

Hello,
Does anyone have plans for the Luna? I would love to build one for my self. I have built the Freebird and its great... I only scratch build and I have never built anything from kits.
Thanks & regards,
Rip