Fast helicopters

"Bart" wrote in message
...
I don't mean to further yet another moronic discussion about yet
another pie in the sky (lol) rotorcraft, but MM, regardless of
who he is, is correct. Ground resonance has nothing to do with
rotor tip speed. Its mainly germane to helicopters which have
shock-struts as the main rotor rotational rate crosses the
resonant frequency(ies) of the struts. It tends to be exaggerated
and more dangerous in machines with four struts and three blades.
Nothing has ever caused my Jetranger to enter the onset of
ground resonance. Know why?; Two blades, No struts....Hmmm.

Mach number my eye, and who the heck cares about ground resonance
in a discussion on increasing Vmax?

Bart

What a nice change, someone who does actually understands something about
the issue!

The reason that a JetRanger can not have ground resonance is that it does
not have lag hinges or other source of flexibility in-plane. If the rotor's
natural lag frequency is higher than the rotor speed, as is the case with
the Bell teetering rotors, it is impossible for it to have a ground
resonance instability. Rotors with this characteristic are called
"stiff-inplane". You can have a stiff-inplane rotor with more than 2 blades
(BO105, BK117) and they too are immune from ground resonance. (If look at a
BO105 or BK117 hub you will not see any lag dampers.)

The struts are associated with ground resonance, but not in the way that you
seem to think. They do not cause the problem; they are there to provide the
damping needed to stabilize the system.

If anyone is interested, we could have a nice little productive thread on
ground resonance. If you do care about this subject, though, please, ignore
that guy "Dennis". He really, really doesn't know what he is talking about
on this subject.

mm wrote:


If anyone is interested, we could have a nice little productive thread on
ground resonance.

Pardon me for sounding snide but if your next nice little productive
thread is like your last one then two other people will participate
besides youself and one of those will be Dennis who you claim
doesn't know what he's talking about.

Sounds like a barn burner to me.

If you do care about this subject, though, please, ignore
that guy "Dennis". He really, really doesn't know what he is talking about
on this subject.

AND YOU DO......!!!!!!!!!!!!!

Your not related to Badwater Bill are you...???????????

George Vranek wrote:
In the last weeks, there is a big silence in this NG regarding fast flying
helicopters. Please have a look at www.vranek.ch/diskrotor.htm and publish
your comments and questions if any in this NG.
Geoge




I see a lot of negativity in this NG about this concept but I feel it
has at laest as much merit as a tilt rotor.

J. Roncallo

My opinions posted on this news group are my own and do not represent
the company I work for.

I agree the concept has at least as much merit as a tilt rotor.
Brien
"John Roncallo" wrote in message
...
George Vranek wrote:
In the last weeks, there is a big silence in this NG regarding fast
flying
helicopters. Please have a look at www.vranek.ch/diskrotor.htm and
publish
your comments and questions if any in this NG.
Geoge
I see a lot of negativity in this NG about this concept but I feel it
has at laest as much merit as a tilt rotor.

J. Roncallo

My opinions posted on this news group are my own and do not represent
the company I work for.

Hallo John, hallo Brien,

thanks for your comparison of the diskrotor with the tiltrotor. But despite
of nearly 50 years long development, the tiltrotor has two faults: It has
not optimal rotors for hovering and not optimal props for cruising. It
means, that a tiltrotor lifts less load in hovering than a conventional
helicopter and cruise slower than a conventional turboprop airplane with
equal installed power.
The diskrotor is optimal for hovering because the big disk brings law and
order in the aerodynamic of a helicopter rotor and the disk with retracted
rotor blades is well suitable for a really fast cruising. Even supersonic
speeds are feasible!!!

George

"brien" wrote in message
...
I agree the concept has at least as much merit as a tilt rotor.
Brien
"John Roncallo" wrote in message
...
George Vranek wrote:
In the last weeks, there is a big silence in this NG regarding fast
flying
helicopters. Please have a look at www.vranek.ch/diskrotor.htm and
publish
your comments and questions if any in this NG.
Geoge
I see a lot of negativity in this NG about this concept but I feel it
has at laest as much merit as a tilt rotor.

J. Roncallo

My opinions posted on this news group are my own and do not represent
the company I work for.

George Vranek wrote:

Hallo John, hallo Brien,

thanks for your comparison of the diskrotor with the tiltrotor. But despite
of nearly 50 years long development, the tiltrotor has two faults: It has
not optimal rotors for hovering and not optimal props for cruising. It
means, that a tiltrotor lifts less load in hovering than a conventional
helicopter and cruise slower than a conventional turboprop airplane with
equal installed power.
The diskrotor is optimal for hovering because the big disk brings law and
order in the aerodynamic of a helicopter rotor and the disk with retracted
rotor blades is well suitable for a really fast cruising. Even supersonic
speeds are feasible!!!

George

"brien" wrote in message
...



I said the concept has at least as much merit as a tilt rotor. I did not
say better or worse. I fully understand the tilt rotors limitations and
some of the disk rotors.

You are still yet to discover the how practical or impractical your
concept is, and who knows maybe it will just be the most practical
concept since the tail rotor. Maybe you will only need 30 years instead
of 50. If you got the funding go for it. Also if you get the funding let
me know.

John Roncallo

"John Roncallo" wrote in message
om...
George Vranek wrote:

Hallo John, hallo Brien,

thanks for your comparison of the diskrotor with the tiltrotor. But
despite
of nearly 50 years long development, the tiltrotor has two faults: It
has
not optimal rotors for hovering and not optimal props for cruising. It
means, that a tiltrotor lifts less load in hovering than a conventional
helicopter and cruise slower than a conventional turboprop airplane with
equal installed power.
The diskrotor is optimal for hovering because the big disk brings law
and
order in the aerodynamic of a helicopter rotor and the disk with
retracted
rotor blades is well suitable for a really fast cruising. Even
supersonic
speeds are feasible!!!

George

"brien" wrote in message
...



I said the concept has at least as much merit as a tilt rotor. I did not
say better or worse. I fully understand the tilt rotors limitations and
some of the disk rotors.

You are still yet to discover the how practical or impractical your
concept is, and who knows maybe it will just be the most practical
concept since the tail rotor. Maybe you will only need 30 years instead
of 50. If you got the funding go for it. Also if you get the funding let
me know.

John Roncallo

Hallo John,

You are right, the most impractical on the diskrotor concept is to get the
funding for it. I have made the first drawing of the diskrotor helicopter in
June 1993 and from that time I have contacted nearly all helicopter makers
(Agusta, Eurocopter, Piasecki, Sikorsky, Westland.........) without any
succes. But I am still optimistic, because the time is ripe for a fast
flying helicopter: There is a certain number of rich people , who are able
to pay 30 millions of US $ for a machine which brings them from New York to
Acapulco without waiting for a slot before take off and without waiting in a
holding pattern before landing. You know, the time is money. If there is a
demand, the suppliers will discover it soon.

George

"George Vranek" wrote in message
...

"John Roncallo" wrote in message
om...
George Vranek wrote:

Hallo John, hallo Brien,

thanks for your comparison of the diskrotor with the tiltrotor. But
despite
of nearly 50 years long development, the tiltrotor has two faults: It
has
not optimal rotors for hovering and not optimal props for cruising. It
means, that a tiltrotor lifts less load in hovering than a
conventional
helicopter and cruise slower than a conventional turboprop airplane
with
equal installed power.
The diskrotor is optimal for hovering because the big disk brings law
and
order in the aerodynamic of a helicopter rotor and the disk with
retracted
rotor blades is well suitable for a really fast cruising. Even
supersonic
speeds are feasible!!!

George

"brien" wrote in message
...



I said the concept has at least as much merit as a tilt rotor. I did not
say better or worse. I fully understand the tilt rotors limitations and
some of the disk rotors.

You are still yet to discover the how practical or impractical your
concept is, and who knows maybe it will just be the most practical
concept since the tail rotor. Maybe you will only need 30 years instead
of 50. If you got the funding go for it. Also if you get the funding let
me know.

John Roncallo

Hallo John,

You are right, the most impractical on the diskrotor concept is to get the
funding for it. I have made the first drawing of the diskrotor helicopter
in
June 1993 and from that time I have contacted nearly all helicopter makers
(Agusta, Eurocopter, Piasecki, Sikorsky, Westland.........) without any
succes. But I am still optimistic, because the time is ripe for a fast
flying helicopter: There is a certain number of rich people , who are able
to pay 30 millions of US $ for a machine which brings them from New York
to
Acapulco without waiting for a slot before take off and without waiting in
a
holding pattern before landing. You know, the time is money. If there is a
demand, the suppliers will discover it soon.

George



I hate to say it but now really isn't the time. The same people that buy
Biz-Jets would be the market ant that market is in the tank.

Also, NOONE would want a fast helicopter more than the military and if any
of the companies above thought the system was viable they would have bought
it or at least optioned it.

George Vranek wrote:


You are right, the most impractical on the diskrotor concept is to get the
funding for it. I have made the first drawing of the diskrotor helicopter in
June 1993 and from that time I have contacted nearly all helicopter makers
(Agusta, Eurocopter, Piasecki, Sikorsky, Westland.........) without any
succes. But I am still optimistic, because the time is ripe for a fast
flying helicopter: There is a certain number of rich people , who are able
to pay 30 millions of US $ for a machine which brings them from New York to
Acapulco without waiting for a slot before take off and without waiting in a
holding pattern before landing. You know, the time is money. If there is a
demand, the suppliers will discover it soon.

George


It is not that it is a diskrotor concept or something new that makes
funding a challange. Funding is always a challenge, I'v seen much more
bizzare ideas get the funding.

All those companys wont be interested unless some government branch like
NASA or DARPA ask's them to research it and pays them to do so. I
suggest you submit the idea as an DOD or NASA SBIR. Visit
http://www.acq.osd.mil/sadbu/sbir/othersites/index.htm. I belive Carter
Copter got started from a NASA SBIR.

My opinions experessed here are my own and do not represent the company
I work for.

John Roncallo

George,

I don't know why you're bothering to blather on about the concept here.
Nobody is going to invest in the concept unless its proven viable. Make
a model and fly it. Thats what most of the chopper inventors did to
prove their ideas.

You also need to revise your ideas about how your example customer
travels. They dont generally need a slot because theyre not parking
their planes at high congestion Class B airports. Since your concept
will never fly at M.77+, it would never be competitive in the 2500nm
range class of aircraft.

Bart


Hallo John,

You are right, the most impractical on the diskrotor concept is to get the
funding for it. I have made the first drawing of the diskrotor helicopter in
June 1993 and from that time I have contacted nearly all helicopter makers
(Agusta, Eurocopter, Piasecki, Sikorsky, Westland.........) without any
succes. But I am still optimistic, because the time is ripe for a fast
flying helicopter: There is a certain number of rich people , who are able
to pay 30 millions of US $ for a machine which brings them from New York to
Acapulco without waiting for a slot before take off and without waiting in a
holding pattern before landing. You know, the time is money. If there is a
demand, the suppliers will discover it soon.

George