The Servo Flap Controlled Rotor for gyrocopters ?

LOL Arnie,
fortunately we have some of the best beers in the world here in Duesseldorf (I don't sound too much of a local patriot, do I ?...;-), so no great risk here!

NO WAY !!!! .... the best beer in the world is Coors Original Banquet , brewed from pure Colorado Spring Water , and no preservatives

And I am Canadian and say so !!

And Adolph Coors came from your part of the world

Nobody can argue those facts !!!

Just go drink one and be happy :) :)

haaaaa best wishes

Then get to heel to work and design some new aircraft !!
 
Each estimate I have so far given in this forum has been so ridiculously wrong that I would actually like to delete all those posts, so no more estimates from me...;-(

Believe me Juergen, I know the feeling quite well.

That's what I envisage ultimately, a four seat Sedan De'Ville Gyro, something along the lines seen below swinging a 60 foot four bladed rotor....;-)

This will be a lesson to me Ed, I don't smoke but I'll think twice before I quit drinking...;-)

I agree, that is a nice looking automobile.....but you really should cut down on the quantity of that Duesseldorf made brew.....it's giving you 60' rotor dreams ;).
Hmm.....maybe brew drinking would help me think again.....

I think Arnie would also like one of these servo-flap controlled gyro rotor thingys.
He is one bright dude too, so he may give advise on the tough parts....
 
How about a 1 blade rotor with counterweight, Juergen? That way, if the counterweight is symmetrical, collective/feathering involves rotation about bearings that don’t have to resist centrifugal force.

One of the predecessor companies of MBB had such a design.

I, in my monkey see/monkey do mode, built such a rotor. But sadly, it didn’t work.
 
It was Bolkow before they merged with Blohm+Voss and Messerschmitt to become MBB later to be gobbled up by Daimler Benz.

Dino
 
How about a 1 blade rotor with counterweight, Juergen?
You must be reading my mind, Chuck! A single bladed rotor is indeed very high on the list of possibilities I would like to investigate. I seem to remember that you mentioned dynamic problems with this system. Do you think the design below would solve these issues?
http://www.google.com/patents/US6619585

Adolph Coors came from your part of the world
He actually came from Barmen, about 20 miles north east of Duesseldorf.... which explains a lot.....(broad grin...)
 
Yes, Juergen, the lift vector of a single blade rotor is tilted toward the counterweight and as the patent says, can be compensated by overbalancing the blade.

That’s not the most serious problem; the counterweight, not being precessed by aerodynamic forces as is the rotor blade, likes to maintain its orbit. It is precessed by the active blade.

But until it catches up, everything is violently out of track. I mean violent.

I managed to get daylight under the wheels of my gyro couldn’t tilt the rotor fast enough to maintain control.

My friend Gary, younger and braver than I, wanted to have a crack at it. I thought; “Why not? He’s young and healthy and won’t have too much trouble growing more skin.”

So Gary took it and as soon as the rotor got up to flying speed, lost the neutral position of the stick. The more he stirred the stick, the worse the vibrations became until it simply hopped over without ever leaving the ground.

Gary did manage to grow more skin.

One blade rotor problems are easily demonstrated with scale models running in front of a large fan or holding out the car window.
 
While you’re exploring things with one blade, Juergen, you might look into one blade propellers that were developed in the 1930s based on, I think, the Tidd patents.

Constant speed is easy, just skew the teeter hinge.

Trouble is, driving force is a moment rather than a couple; the propeller would rather stand still and force the drive shaft to go in a circle.

I would Google it except my high speed internet connection is down and I’m limping along on dial up with a noisy, rural telephone line. About as much fun as a visit to the dentist.
 
The more he stirred the stick, the worse the vibrations became until it simply hopped over
If things get out of hand it is quite often some sort of resonance. On the other hand the Boelkow team has actually flown a single blade helicopter and quite well at that so it seems to be a case of the right design. The question is whether they have published enough on the way to allow those following their footsteps to achieve success easier and faster. Such a design, when started from scratch, might require a team of experts and thus would be beyond my capabilities. I will definitely continue to collect material on single blade rotors and any contribution is of course highly appreciated.
I’m limping along on dial up with a noisy, rural telephone line
Good grief, Chuck, that sounds awful! Hope you're quickly back in the 21st century!
the propeller would rather stand still and force the drive shaft to go in a circle
WWII fighter planes do this if you gun the engine at slow speed without enough aileron authority. They are flipped right on their backs by their props and if you don't have miles of height you're done.
the Tidd patents
Thanks for the hint, Chuck, Tidd seems to have analyzed the problem and it seems he came up with some good ideas:
http://www.google.de/patents/US2297815
Pitcairn is refering to Tidd's work:
http://www.google.com/patents/US2742095

The Tidd prop was briefly discussed here:
http://vps.zoniehosting.com/~rotary/forum/showthread.php?t=18855
 
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In case you hadn’t noticed, Juergen, the Boelkow helicopter used a Hiller servo rotor. With this, they were probably able to slow rotor precession rate enough to get vibration to a livable level.

Still, there is the problem of rotor thrust vector not concentric with rotorhead axis as well as unbalanced drive torque.

The bottom line is that neither the one blade propeller or the one blade rotor ever got beyond the tinkering stage.

Both, at first glance, appear to offer something for nothing.

Constant speed prop without feathering bearings and complex hydraulic/electric control.

A rotor without heavily loaded feathering bearings.
 
Hans Derschmidt was a prolific German rotor designer. His patent on a single blade rotor seems to go still further in using an unbalanced mass to reduce vibration:
http://patentimages.storage.googleapis.com/pdfs/US3074487.pdf
With this, they were probably able to slow rotor precession rate enough to get vibration to a livable level.
Unfortunately I currently do not have a sufficient grasp on the theory to explore your remark, Chuck, I'll file it for later use...;-)
 
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Yes, Juergen, I’m aware that drive torque moment can balanced by a counterweight at 90º to blade axis. The auxiliary counterweight position must shift in accordance with drive torque.

However, there is no way of producing moment balance in a single blade rotor undergoing precession. The vertical impulse on the rotor shaft can get quite violent during rapid precession.

In the bottom sketch, imagine a rotor something like a Bell gyro stabilizer bar being processed by an air jet. Every time the active blade passes over the air jet, there is a vertical force applied to the rotor shaft.

My high speed internet connection is back up and running, so I've reentered the 21th century.
 

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Juergen,
Unless I misunderstood, the counterweight on the side only can accurately balance the drag of the single blade and delete this vibration 1/rev.
But if the blade pitch is different (drag changes), then the vibration reappears, right?
 
Non, il me semble par contre que Derschmidt a essayé de relier les deux effets, ce qui me semble evident en lisant la partie laquelle j'ai essayé de traduir:

Francais:
Par la manière de la fixation de la masse sur la lame de rotor, la distance de la masse par rapport a l'axe de rotor change en fonction de l'angle d'attaque ou l'angle de tangage de la lame, pour qu'avec un petit angle d'attaque, conforme à un grand bras de levier efficace, un grand déséquilibre soit produit et avec un grand angle d'attaque, conforme à un petit bras de levier efficace, un petit déséquilibre est produit.

English:
Owing to the mounting of the mass on the rotor blade, the distance of the mass from the rotor axis changes in dependence upon the angle of adjustment or pitch angle of the blade, so that with a small pitch angle, corresponding to a large effective lever arm, a large unbalance is produced, and with a large pitch angle, corresponding to a small effective lever arm, a small unbalance is produced.
 
Now I know the trick of Dershmidt. Thank you for your lightening, Juergen.
 
À votre service, Monsieur....;-)
J'ai remarqué que vous prenez un très grand intérêt en ce type de question et je crois qu'il est magnifique d'avoir quelqu'un dans le forum avec votre sorte d'expertise dans le domaine de la dynamique de corps élastique et rigide!

I noticed that you take great interest in this type of question and I think it's great to have someone in the forum with your kind of expertise in the field of elastic and inelastic body dynamics!
 
I’m nosy, Juergen; -does your proficiency with French equal your proficiency with English? Amazing if so.
 
Oh no, Chuck. A translation like this takes several minutes and I'm cheating by looking up words as well as terms and phrases...;-).....plus there are several glitches in the sentence e.g. it should probably be "des corps" but I am not even sure about that...;-(
My French is perhaps best described by the term "Je me débrouille" (I'm muddling through)
 
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Juergen, I always try to see the realistic possibility to fly cheaply
Here is my rough theoretical evaluation of the single-blade relatively to two blades ( ) with the same aspect ratio for lift 900 lbs,
- Blade(s) Single R = 16' x 10" (two blades R =11.5' x 7")
- Rrpm : 280 t/mn (550 t/mn)
- Profile power counter weight included: 14 HP (25 HP)
- Induced power hover : 34 HP (44 HP)
- Ascension power to 800 ft/mn hover: 12 HP (11 HP)
- Max descent rate before VRS: 600 ft/mn (900 ft/mn)
- Rotor mass counter weight included: 80 lbs (20 lbs)
- Delay after engine failure: ? s (? s)

Oh, Your French is perfect !
 
This is a very interesting example. In my design the emphasis is on a very low minimum speed, a bit like the Fa-330 which was designed to fly a the maximum continuous speed of a German type IX fleet submarine (18 knots). Do I get you right that the single blade has a lower rate of descent and a lower total power required? In that case the single blade might be the rotor type of choice for my design.

PS: Vous êtes trop gentil!
 
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Do I get you right that the single blade has a lower rate of descent and a lower total power required?
Of course Juergen. With the same aspect ratio required for a sufficient stiffness of the blade, the swept area is larger and therefore the lowering speed decreases if engine out.
However, in my opinion, this can be a disadvantage in approach with motor, because of the increased proximity of VRS.
 
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