Homebuilt Coaxial Helicopter (RELOADED)

Rotor Rooter

Dave Jackson
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Cita,

I agree, when you say that yaw control can be handled by the inclusion of a 'differential' in the gearbox.

This is the proposed method in the web page mentioned above; [Coaxial Transmission w/ Yaw Control ~ With larger version of drawing just added.].

By clutching the central back-to-back crown gear to either the upper or the lower crown gear the relative rpm (and drag) of the two rotors can be varied + or -, thereby producing yaw. In addition, the pedals will not have to be reversed during autorotation.

By braking the central back-to-back crown gear the rpm of the two rotors will be equal, but opposite.

By the application of an incremental rotation of the back-to-back crown gear the crossing azimuth of the upper and lower blade can be changed.


Should you, or anyone disagree with this, please say so.

Dave
 
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Fly Army

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Ballistic Recovery ?????

Ballistic Recovery ?????

On their technical data page at the bottom they list "Ballistic Recovery". Why ?????? and more precisely ...HOW ???
 

brett s

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I'm with you on that, makes no sense to me either - just wasted payload & money. Marketing hype only IMO...

If the rotors are still attached & spinning, no way you'll be able to deploy safely - if they aren't, odds of surviving are about nil regardless.
 

Sita

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Hello Dave,

I'm still pondering over your design but at first glance it seems to me that the forces will cancel each other leaving no yawing force.Like I said though I'm still try to grasp the idea (grin-grin)

cita
 

Rotor Rooter

Dave Jackson
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Andre,
I am sure, Dave, that you can do simpler!!!
Hell, anyone can make it simpler. This complicated transmission was designed for rotornaughts who enjoy maintaining more than flying. :)

Seriously, the only advantage it offers over 1 pinion and 2 crown gears is that it does not require pedal reversal during an infrequent autorotation.
It's just an idea from the Department of Demented Designs.

Dave
_____________________________
Edited to add a 'More Seriously'

You want something simple. I'll let you in on a secret; but don't tell anybody or I'll have to shoot you. :laser:
Go to Goggle and search on [ElectrotorSimplex]
 
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joe nelson

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Wasn't there a coax aircraft several years ago called the Pearch Eagle or something like that? It had two 503s as powerplants but couldn't autorotate so it wasn't a commerical success.
 

PTKay

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PTKay

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Servo flaps:

In Conclusion

As can be gathered from this analysis, the servo flap provides the whole helicopter with more stability with regard to angle of attack than other rotor control systems. It is easier to give wider margins for rotor blade flutter and it reduces the requirements for an AFCS to give good handling characteristics especially in gusts. It is lighter than other systems and needs no hydraulics, yet it gives better rotational inertia, which is important for good autorotational characteristics.

The servo flap is extremely simple in concept and execution yet very effective in control. The reasons for its application in helicopter design being limited to exactly one company are rather hard to comprehend, nevertheless should not be attributed to flaws in the system.

http://www.helis.com/howflies/servo.php
 

joe nelson

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I love those servo flaps and work on mine each day...working on the swash plate control system (classic gimbal) today. Had a idea of using uhmw plastic in lieu of the bearings.
 

PTKay

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This is the answer I got from them:


vielen Dank für Ihr Interesse an unseren Helikoptern. Der Eaglet kostet, je nach Ausstattung des Kits, zwischen 60.000 € und 100.000 €. Die genauen Optionslisten sind in Vorbereitung, wir schicken sie Ihnen gerne zu, wenn sie bereit sind.
Ausgeliefert werden die ersten Kits in der zweiten Jahreshälfte 2008.

Mit den besten Grüßen, / Kind regards,

Christian Frey, CEO


"...thank you for your interest in our helicopters. The Eaglet costs, depending upon equipment of the kit, between 60.000€ and 100,000€. The exact option lists are in preparation, we dispatch them to you gladly, if they are ready. The first kits shall be delivered in the second half of the year 2008."
 

PTKay

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Eaglet is a kit,
Xenon - ready to fly....

Small difference. ;)
 
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