Help me Birdy

[Chuck_Ellsworth]

I hate to start more discussion on the down wind turn again, but I really do have a problem now.

I was trying to figure out more about the down wind turn thing, so I decided to wait until a good wind was blowing and then to day I got my chance to experiment.

Now I've lost my flying machine.

Birdy help me...

My boomerang didn't come back! :D

Any suggestions?

Chuck

[mceagle]

Chuck,
I do not believe that you would re-start such a post on a frivolous whim. Could you give us more information please, or is this just a boomerang joke?
If the latter,
"then there is a trick, and to you I'm gonna show it,
If you want your boomerang to come back, first you've got to throw it".

[Hognose]

Ah, Chuck, it's a simple matter of aerodynamics. Most boomerangs sold to tourists and whatnot are close replicas of the Australian aboriginal weapon. They are optimized for flight in the outback! Think hot and high. The only place in the solar system suitable for testing for outback conditions is the sunny side of the Planet Mercury -- hot as blazes and airless as a tomb. The poor ickle boomerang's Reynolds numbers are all wrong for the dense air of coastal Canada, where it's 30 degrees C cooler. Sucker's probably still climbing.

You need to (your option) hire an aerodynamicist like Dave Lednicer, or spend some quality time swotting up on a good aero book (I recommend Hoerner's 2 volumes, Fluid Dynamic Lift and Fluid Dynamic Drag). I know you have to have a grasp of higher maths cause you've done fuel management on Catalinas.

Anyway, take your aero book, and duplicate the tourist boomerang, only, change the airfoils throughout to conform to your intended aerodynamic environment. Particularly on the rainy pacific coast, the best airfoils are the ones the Navy uses on sub control surfaces.

And Tim -- I can't speak for Chuck, but *this* is just a boomerang joke. Mate.

cheers

-=K=-

[Udi]

There is one principle, Chuck, that you still don't understand. You've got to throw the boomerang in such a way that it turns into the wind - i.e. upwind, not downwind! When the boomerang turns upwind, it get additional lift - just like airplane. If you throw it in a way that it turns downwind, of course it would lose lift and crash. Duh! :rolleyes:

You, of all people, should know that!

Udi

[barnstorm2]

Kevin,

Right mate, I was afraid that boomerang joke would come back to me. :D

[birdy]

Q; Whot you call a boomerang that won't cum back???
A; A stick.

[le-wardy]

That's why you've got the cattle dog nearby to go get that one.

[Chuck_Ellsworth]

Thank God for this conference, I knew that if I asked the right people a question I would get a sensible answer.

My admiration for your knowledge is going up Birdy, now one more question.

Was Australia once the name of a prison in England? :D

And do you use a GPS to navigate in your area?

There, that is two more questions.

Chuck

[mceagle]

Just another interesting thing. I wonder how many people realise that the Australian Aborigionals utilized the principle of Autoration (Boomerang) some 30,000 years before Cierva was even born.

[birdy]

Chuck E.,
Way back on some other thread I said somethi'n like,"now I know I can never take you seriously".Good thing I'v got a bit of memory in me hollow head or you'd be mak'n me look a d..kh..d again ay.

Tim,mate,surely your not serious.[I read that crap too.]

[Chuck_Ellsworth]

Hey Birdy :

I quite enjoy your posts and am truly impressed with your use of a gyro in your cattle business.




I posted the boomerang thing as a joke just for fun.

Maybe someday I shall get to visit with you and of course Paul, then we can really share our thoughts.

As far as the down wind turn stuff goes I come at these things from a different sector of aviation than the gyro group, we are maybe just to structured and set in our ways...

The bottom line is regardless of aerodynamics and physics if you can make your gyro do what you want, that is all that matters.

Chuck

[birdy]

I reckon the major difference between us Chuck is that you fly many different typs of machines,I only fly one.
You'd have to be structured in your approche coz your not tuned into or familuar with every type you fly,you have to be flexable and adapt to the airodinamics and aspects of the different flying characteristics of many different machines.

My little brain is only tuned to one machine,and it don't handle change very well.

[Chuck_Ellsworth]

And if it works, don't fix it. :D

[mceagle]

Birdy,
Yes, I am serious. It may not have been 30,000 years ago but ancient carvings show that it certainly was many thousands of years ago. Perhaps we should look deeper into this ancient tool because a Boomerang in autorotation has a far better glide ratio than a gyroplane in autorotation.

[Hognose]

a Boomerang in autorotation has a far better glide ratio than a gyroplane in autorotation.

Tim, and guys:

d'ya think that the fact that a boomerang has no part which is not part of the aerodynamic lift surface, might have something to do with that?

A gyroplane has a mast, a fuselage or frame of some type, a powerplant (gyrogliders excepted, obviously) and a pilot. All of this stuff is a parasitic user of the lift provided by the rotor -- it doesn't provide any list itself. It does provide drag, but that's scarcely helpful in the glide ratio department.

You are quite right, though, that a boomerang is the oldest man-made example of autorotation. I use the qualifier man-made advisedly: some species of trees' seeds exhibit autorotation (sycamore, sugar maple). See here: http://jrscience.wcp.muohio.edu/nsfall00/FinalArticles/MAPLESEEDDISPERSAL-THEFIN.html

Interesting that the unique boomerang would be developed by the indigenous people only in Australia, the home to so many other oddities and "one-off" creatures. It makes sense in a down-under way, doesn't it?

cheers

-=K=-

[birdy]

Your spoton Kevin.
I reckon if I hung me gyro under a bent stick it wouldn't go far.

Yes,they did and still do MAKE them,but they didn't "invent" autorotation.

And they sure as hell didn't understant autorotation.They just knew that a bent stick of a certain "profile" could "fly".And after playi'n with it for a few thousand years,they got very clever at it.

If you have an open mind and want to know how they realy "discovered" the boomerang ,that's a different story.

[mceagle]

Kevin,
I've often wondered whether the seeds autorotate or windmill. I will have a look at that site you suggested.
A gyroplane is certainly a drag machine but it is curious that even utilizing as much streamlining as the Hinchman H1 Racer, the top speed is not that much greater than an equivalent open frame machine.

[Chuck_Ellsworth]

Maybe its not aerodynamics, I bet its black magic. :D

Birdy???

[birdy]

It's just magic Chuck,no need to be racist. ;)

Tim,if you compare the gyro's engine power to the machines weight,and the boomerang's power[blokes arm] to it's weight, and thow into that comparison the drag of the gyro,the boomer should sail forever.[besides,I can't imagine muster'n with a boomerang]. :D

[Chuck_Ellsworth]

Naw, Birdy that was not rasist. I used it as a play on words.

Black magic is a common saying in North America that has no rasist overtones, actually I think the saying comes from Benin in Africa where voodoo and black magic originated. :D

Having worked in Benin among many, many other countries on that dark continent I am quite familiar with their superstitions and unusaual beliefes.

Boy, you and me just got to get together some day and straighten out all the worlds ills. :D

Chuck E.

[le-wardy]

Chuck, if you're going to get together with Birdy to straighten out the worlds ills. You better have a lot of that 'black magic' (rum) handy to pour down that dry, parched bloody throat of his. He's gonna need it, that's for sure.

And Chuck, you're right about 'black magic' not being an racist overtone.

[birdy]

Oi chuck,me "rasist" comment was a joke,.........gotcha.
The "rasist" tag here in Oz gives me the sh.ts,you can't evan call a blackfella a blackfella anymore.The ol blackfella can't call me a whitey either,wot ever happened to the old days when you called a spade a spade,and everybody knew wot you was talk'n about.
luckily,out here in the middle of no were ,blackfellas are called darkys,white fellers are called whiteys and we all get along good.[anyone who calls anyone a rasist gets a tuneup.]

[Hognose]

A gyro is certainly a drag machine but it is curious that even utilizing as much streamlining as the Hinchman H1 Racer, the top speed is not that much greater than an equivalent open frame machine.

Tim,

most of the drag in a gyro is induced drag from the rotor. Streamlining helps you with form drag, parasitic drag, but the only way to reduce that induced drag... is to reduce the lift being produced by the rotor. Bit of difficulty there is that the lift is what keeps you from heading towards the centre of Earth at 32 fps/s (for our international audience 9.8 m/s/s).

Some fast rotorcraft have tackled this by using counterrotating rotors. For instance on a CH47 (Chinook) the rotor lift is laterally balanced because the fore and aft rotors counterrotate, and the machine can operate at higher forward speeds than a penny-farthing (main rotor/tail rotor) machine. It's still Mu-limited. Some Russian c/r choppers can make some high speeds; their rotors are on a single mainshaft and the limitation here is that you can't have flapping enough for advancing and retreating rotor to make contact, or bad things result.

Carter uses a very rigid (i.e. flapping-safe) rotor slowed down and in forward flight, relies on the stub wings to provide the lift at considerably less drag than a rotor system. In essence the CarterCopter Technology Demonstrator is a fixed wing airplane that uses a gyroplane rotor as a high-lift device! Advantages are many, for one thing the wing can be optimised for cruise with not a thought given to slow flight; the only machines that I know that allow a similar optimisation are air-launched (and comparing the wing of the Ryan Firebee drone to that of the CCTD is interesting).

cheers

-=K=-

[Heron]

Pelé the King of Football (yes the one played with the feet) is known as Negão (Big Black or Very Black) and especially for those closer to him, never heard of complaints.
Besides . . .in the climax of passion men and women call themselves "Meu Nêgo or MInha Nêga" . . .go figure! Its terms of endearment to darken someones collor even if they are blond blue eyed.
But again Brazil is a mulato country!
Heron

[mceagle]

Indubitably?