number of rotor blades

(Shaber CJ) wrote in
:

I do know a an accident with a glider where the pilot lost a wing,
spin down into a marsh with big fluffy trees and survied. It happened
in Florida a few years ago and the glider was a 1-26.

A few people have survived parachute jumps when the chute didn't open, too,
but it's certainly not common. Anything is possible.

--
Regards,

Stan

Sikorsky has a couple of patents for 'Rotor system having alternating length
rotor blades'. [U.S. patent #5,620,303]

This is not to suggest that the removal of a portion of the blade on the
ground is the same as the removal of a portion of the blade in the air.


"Shaber CJ" wrote in message
...
Subject: number of rotor blades
From: Stan Gosnell

It isn't survivable, just as losing a wing on an airplane isn't
survivable, except in the most unusual of circumstances.

--
Regards,

Stan

I do know a an accident with a glider where the pilot lost a wing, spin
down
into a marsh with big fluffy trees and survied. It happened in Florida a
few
years ago and the glider was a 1-26.

Craig

Dave Jackson wrote:
Sikorsky has a couple of patents for 'Rotor system having alternating length
rotor blades'. [U.S. patent #5,620,303]

This is not to suggest that the removal of a portion of the blade on the
ground is the same as the removal of a portion of the blade in the air.



I can garantee that any of these designs still keep the rotor system
balanced.

A Hughes 369D lost a blade here in B.C. A few years back, it brought up a
whole bunch of issues with the blades.
Here is report:
http://www.tsb.gc.ca/en/reports/air/...8/a00P0208.asp

Mike


"Rob Fonhof" wrote in message
...
Just a theoretical question that someone may be able to help with.
Alot of helicopters have only two rotor blades, ie:Robinsons, Bells, etc.
Others have multiples, ie:dauphins with 4, Hughes etc.
If a blade is thrown on a two blade, bend over and kiss your rear bye bye.
What would happen if you had a 4, 5, or even 6 blade?Would you still be
able
to autorotate? I know the airframe would probably vibrate violently, but
would it be survivable in an autorotate, or even low power to at least get
to the ground.
Have there been instances in the past where this has happened with a 2
blade.
Thanks in advance.
Rob Fonhof

You will still have to bend over and kiss your behind and
I would suggest that you do it rather quick.



"Rob Fonhof" wrote in message ...
Just a theoretical question that someone may be able to help with.
Alot of helicopters have only two rotor blades, ie:Robinsons, Bells, etc.
Others have multiples, ie:dauphins with 4, Hughes etc.
If a blade is thrown on a two blade, bend over and kiss your rear bye bye.
What would happen if you had a 4, 5, or even 6 blade?Would you still be able
to autorotate? I know the airframe would probably vibrate violently, but
would it be survivable in an autorotate, or even low power to at least get
to the ground.
Have there been instances in the past where this has happened with a 2
blade.
Thanks in advance.
Rob Fonhof

Hennie: With the vibration level you would have with a missing blade I
doubt if you could find your behind let alone aim a kiss at it. Having had
one just slip out of track in flight was enough to tell me I would have had
trouble kissing anything.
Stu Fields

"Hennie" wrote in message
om...
You will still have to bend over and kiss your behind and
I would suggest that you do it rather quick.



"Rob Fonhof" wrote in message
...
Just a theoretical question that someone may be able to help with.
Alot of helicopters have only two rotor blades, ie:Robinsons, Bells,
etc.
Others have multiples, ie:dauphins with 4, Hughes etc.
If a blade is thrown on a two blade, bend over and kiss your rear bye
bye.
What would happen if you had a 4, 5, or even 6 blade?Would you still be
able
to autorotate? I know the airframe would probably vibrate violently,
but
would it be survivable in an autorotate, or even low power to at least
get
to the ground.
Have there been instances in the past where this has happened with a 2
blade.
Thanks in advance.
Rob Fonhof

"Rob Fonhof" wrote in message
...
Just a theoretical question that someone may be able to help with.
Alot of helicopters have only two rotor blades, ie:Robinsons, Bells, etc.
Others have multiples, ie:dauphins with 4, Hughes etc.
If a blade is thrown on a two blade, bend over and kiss your rear bye bye.
What would happen if you had a 4, 5, or even 6 blade?Would you still be
able
to autorotate? I know the airframe would probably vibrate violently, but
would it be survivable in an autorotate, or even low power to at least get
to the ground.
Have there been instances in the past where this has happened with a 2
blade.

Brantly B2s had a problem in the early '70s. I personally saw a blade come
off one. The other blades pulled the gearbox off the airframe. Two on board
but only one was killed as the machine was only at 20 ft.

Slatts

Losing a MR blade in flight results in certain death, but what about
having a blade delaminate? That is, part of the skin comes off but
the main chord is still attached?

Dennis.


Dennis Hawkins
n4mwd AT amsat DOT org (humans know what to do)

"A RECESSION is when you know somebody who is out of work.
A DEPRESSION is when YOU are out of work.
A RECOVERY is when all the H-1B's are out of work."
To find out what an H-1B is and how they are putting
Americans out of work, visit the following web site
and click on the "Exporting America" CNN news video:
http://zazona.com/ShameH1B/MediaClips.htm

Well its a rough ride down but definitely controllable. The BK117 has had
this happen numerous times (I would guess about 15 times, all landed
safely). The engine cowling is being left unlatched (this is not the
mechanics or pilots story) and is coming open in flight striking the M/R
blades. The M/R blades tear the cowling off the airframe and upward into
the rotor system. The result is almost always large sections of M/R
skin/foam being ripped off a blade or two. I've seen several BK blades that
had 3 foot sections missing, from the spar back. The worst one I ever saw
was an Omniflight BK that lost the last 6-8 feet of the Skin/foam off 1
blade. All that was left on the outer 6-8 feet of one blade was the spar.
Like swinging a stick around. The pilot did a great run on landing in some
frozen field but he said everything was just a blur all the way down from
the imbalance. I've heard many stories of aircraft loosing large parts of
blades (shot off) in Vietnam. It livable if you just loose the light stuff.
Most of the weight is spar and metal eroision strip, thats the stuff you
want to keep onboard. I've been looking thru my stuff since this tread
started looking for a weight figure I read one time on what the centrifical
load was on a 206 M/R blade but can't find it. I remember it was a whole
lot more force than I ever would have guessed. Made me respect for the
strength of those TT straps.JC

wrote in message
...

Losing a MR blade in flight results in certain death, but what about
having a blade delaminate? That is, part of the skin comes off but
the main chord is still attached?

Dennis.


Dennis Hawkins
n4mwd AT amsat DOT org (humans know what to do)

"A RECESSION is when you know somebody who is out of work.
A DEPRESSION is when YOU are out of work.
A RECOVERY is when all the H-1B's are out of work."
To find out what an H-1B is and how they are putting
Americans out of work, visit the following web site
and click on the "Exporting America" CNN news video:
http://zazona.com/ShameH1B/MediaClips.htm

I had heard that the centrifugal load on the hub from the blade is
something like 25,000 lbs for a small helicopter. I'm sure that there
is a formula somewhere that takes the total weight of the blade, the
RPM and the length. I don't have it though. I'd have to brush up on
my calculus to figure out the formula. I'm sure that someone here
probably has it already figured out.

Dennis.

"Helimech" wrote:

blades (shot off) in Vietnam. It livable if you just loose the light stuff.
Most of the weight is spar and metal eroision strip, thats the stuff you
want to keep onboard. I've been looking thru my stuff since this tread
started looking for a weight figure I read one time on what the centrifical
load was on a 206 M/R blade but can't find it. I remember it was a whole
lot more force than I ever would have guessed. Made me respect for the
strength of those TT straps.JC


Dennis Hawkins
n4mwd AT amsat DOT org (humans know what to do)

"A RECESSION is when you know somebody who is out of work.
A DEPRESSION is when YOU are out of work.
A RECOVERY is when all the H-1B's are out of work."
To find out what an H-1B is and how they are putting
Americans out of work, visit the following web site
and click on the "Exporting America" CNN news video:
http://zazona.com/ShameH1B/MediaClips.htm