Have there been any successful tip-jet helicopters?

(Jeremy Thomson) wrote in message om...
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

I think that the general concensus is that they all proved extremely
noisy and consumed an inordinate quantity of fuel, 2 factors that have
limited their success and further development.

Ken J. - Sandie A. Geaux

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

Ah, another IE-only page. The site is busted, it relies on out-of-date javascript.

I viewed the Sud-Ouest SO.1221 Djinn at
http://avia.russian.ee/vertigo/snias_jinn-r.html (thanks, Brantly Nut), and
deleted my helis.com bookmark.

terra wrote in message ...
David Lednicer wrote:
I got this when I tried to view it with Netscape 7.02, so I switched and
tried IE 6.0 and it worked.

Ah, another IE-only page. The site is busted, it relies on out-of-date javascript.

I viewed the Sud-Ouest SO.1221 Djinn at
http://avia.russian.ee/vertigo/snias_jinn-r.html (thanks, Brantly Nut), and
deleted my helis.com bookmark.

I didnt know this group was for rating sites ! :-)
Is not my fault if netscape versions are not backwards compatibles,
anyway, I just download, install and review NS7 and update the
scripts.
Hope its works fine now

jorge wrote:
terra wrote in message ...
David Lednicer wrote:
I got this when I tried to view it with Netscape 7.02, so I switched and
tried IE 6.0 and it worked.

Ah, another IE-only page. The site is busted, it relies on out-of-date javascript.

I viewed the Sud-Ouest SO.1221 Djinn at
http://avia.russian.ee/vertigo/snias_jinn-r.html (thanks, Brantly Nut), and
deleted my helis.com bookmark.

I didnt know this group was for rating sites ! :-)

It's for bashing IE-only sites. If the trend continues, the web will be
accessible not just to IE users only, but to *Windows* users only. No Mac, and
no Linux.

Is not my fault if netscape versions are not backwards compatibles,

I don't know what you're saying here. Your script looked for Netscapes 4 and 6,
no awareness of 7.
So I fired up Netscape 4.79... and... the page didn't load at all! Nothing.
After I disabled Stylesheets it loaded, but then the links didn't work.

anyway, I just download, install and review NS7 and update the
scripts.
Hope its works fine now

Thank you! It works in 7, but not old 4.79, which is good enough.

BTW, AOL has recently closed up the Netscape shop, the company is out of
business, so you won't have to look for a Netscape 8 :-(
But... development on Mozilla continues :-)
It's the "same" browser, without the Netscape name in the identifier. There's a
family of other browsers also based on Mozilla: K-Meleon, Beonex, Firebird, IBM
Browser, etc. And then there's Opera. Will your site work with those? I think
the javascript is a bad idea.

In message , terra
writes
David Lednicer wrote:
I got this when I tried to view it with Netscape 7.02, so I switched and
tried IE 6.0 and it worked.

Ah, another IE-only page. The site is busted, it relies on out-of-date
javascript.

More likely that Netscape is busted, as it's riddled with
non-html4-compliant errors.


--
Rod Buck

Rod Buck wrote:

In message , terra
writes
David Lednicer wrote:
I got this when I tried to view it with Netscape 7.02, so I switched and
tried IE 6.0 and it worked.

Ah, another IE-only page. The site is busted, it relies on out-of-date
javascript.

More likely that Netscape is busted, as it's riddled with
non-html4-compliant errors.

No, Netscape 7 is the most standards-compliant browser out there by a long
stretch, as in 100% compliant. You're thinking of Netscape 4.

If you want to see a busted browser, go to
http://www.meyerweb.com/eric/css/edg...iral/demo.html with IE.
Or try any of the other demos listed at
http://www.meyerweb.com/eric/css/edge/index.html

No, Netscape 7 is the most standards-compliant browser out there by a long
stretch, as in 100% compliant. You're thinking of Netscape 4.

If you want to see a busted browser, go to
http://www.meyerweb.com/eric/css/edg...iral/demo.html with IE.
Or try any of the other demos listed at
http://www.meyerweb.com/eric/css/edge/index.html

True Netscape 4 was garbage, but I have little experience of Netscape 7
- didn't want to waste time finding out....




--
Rod Buck

Rod Buck wrote:


No, Netscape 7 is the most standards-compliant browser out there by a long
stretch, as in 100% compliant. You're thinking of Netscape 4.

If you want to see a busted browser, go to
http://www.meyerweb.com/eric/css/edg...iral/demo.html with IE.
Or try any of the other demos listed at
http://www.meyerweb.com/eric/css/edge/index.html

True Netscape 4 was garbage, but I have little experience of Netscape 7
- didn't want to waste time finding out....

You certainly shouldn't risk finding anything out.

Ken's right - tip jet designs seem like a great idea - no transmission,
minimal antitorque (you still have a small amount of friction torque and you
have to have some form of yaw control) - but tip jet drive is incredibly
inefficient. I researched these a number of years ago, as a young engineer.
I remember a quote about the YH-32, to the effect that its major success was
it's ability to turn fuel into noise.

Dan Hollenbaugh

Ken Sandyeggo wrote in message
. ..

I think that the general concensus is that they all proved extremely
noisy and consumed an inordinate quantity of fuel, 2 factors that have
limited their success and further development.

Ken J. - Sandie A. Geaux

"Dan & Jan Hollenbaugh" wrote in message
...
Ken's right - tip jet designs seem like a great idea - no transmission,
minimal antitorque (you still have a small amount of friction torque and
you
have to have some form of yaw control) - but tip jet drive is incredibly
inefficient. I researched these a number of years ago, as a young
engineer.
I remember a quote about the YH-32, to the effect that its major success
was
it's ability to turn fuel into noise.

The reason the British Rotordyne was finally scraped was because of the
noise problem.
Unfortunately government committees work so slowly that the problem was
almost solved before they finally scrapped it!
So it is possible to quieten tip jets down. I believe they did it by
changing the original round exits into long trailing edge slots.
http://www.asra.org.au/rotordyn.htm

Slatts