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Have there been any successful tip-jet helicopters?



 
 
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  #1  
Old July 24th 03, 04:40 AM
Jeremy Thomson
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Default Have there been any successful tip-jet helicopters?

I'm not aware of any tip-jet helicopters that have made it into
production.
Please correct me if I'm wrong.

At first the idea seems a no-brainer, no torque to counter, no
gearbox, should result in a lighter & thus more efficient aircraft.
I suppose the devil is in the details.
Is the problem with tip-jets the rotor hub?
Either you have to pass fuel or hot gas through the rotor hub to the
blades.
I guess sealing a rotating assembly with hot gases flowing through may
be a non-trivial problem?
But that shouldnt be a problem for jets-at-the-tips type designs, fuel
would not be hot enough to damage seals.
Perhaps there is a inherant flaw in the jets-at-the-tips style design?

I've seen videos of the Hughes heavy lift helicopter that directed the
output of a couple of turbojets(/fans ?) through the blades.
I thought that design was successful, it was more a matter of funding
that it wasnt put into production, am I wrong?

Jeremy Thomson
  #3  
Old July 24th 03, 09:18 PM
Scott Gardner
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Default

I can't say it was successful in terms of production, but I did see it fly.

Go to: http://www.intora-firebird.com/main.htm

Scooter

"Jeremy Thomson" wrote in message
m...
I'm not aware of any tip-jet helicopters that have made it into
production.
Please correct me if I'm wrong.

At first the idea seems a no-brainer, no torque to counter, no
gearbox, should result in a lighter & thus more efficient aircraft.
I suppose the devil is in the details.
Is the problem with tip-jets the rotor hub?
Either you have to pass fuel or hot gas through the rotor hub to the
blades.
I guess sealing a rotating assembly with hot gases flowing through may
be a non-trivial problem?
But that shouldnt be a problem for jets-at-the-tips type designs, fuel
would not be hot enough to damage seals.
Perhaps there is a inherant flaw in the jets-at-the-tips style design?

I've seen videos of the Hughes heavy lift helicopter that directed the
output of a couple of turbojets(/fans ?) through the blades.
I thought that design was successful, it was more a matter of funding
that it wasnt put into production, am I wrong?

Jeremy Thomson



  #6  
Old July 25th 03, 03:34 AM
terra
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Default

David Lednicer wrote:

The Sud-Ouest SO 1221 Djinn was the only one that was at all succesful.
The US Army evaluated three as the YHO-1.

See: http://www.helis.com/timeline/aerospatiale.php


Did *you* click the link to see the Djinn? With your Netscape 7.02?
Using 7.1, almost every link gets me a popup box telling me I need Netscape 4 or
higher. Duh.

  #7  
Old July 25th 03, 03:52 AM
terra
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Default

Brantly Nuts wrote:

There have been at least 2 tip-jet type helicopters to reach type
certification and production.

Sud Ouest So.1221 Djinn, about 150 produced.
http://avia.russian.ee/vertigo/snias_jinn-r.html

Kolibri H-3, about 10 produced.
http://avia.russian.ee/vertigo/nhi_kolibri-r.html


It says version #1 "was written off through ground resonance". Maybe due to
something like a fuel imbalance through the blades, because 2-blade rotors don't
suffer from ground resonance. Do they?

  #8  
Old July 25th 03, 11:59 AM
ops
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Default



Jeremy Thomson wrote:
I'm not aware of any tip-jet helicopters that have made it into
production.
Please correct me if I'm wrong.





Where does the Hiller YH-32 fit in then?

http://www.museumofflight.org/collec...lay.html?ID=59

http://avia.russian.ee/vertigo/hiller_hoe-1-r.html


rm

  #9  
Old July 25th 03, 05:59 PM
David Lednicer
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Posts: n/a
Default


I got this when I tried to view it with Netscape 7.02, so I switched and
tried IE 6.0 and it worked.

 




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