What would cheyenne look like today?

[Mr.Creak]

Or the Mauser recoil-less RMK-30.
Planned later versions (although single-barrel) have greater muzzle energy than the GAU-8 and it's perfect for helicopter applications.

[rickshaw]

What about replacing the diddy little XM140 30mm cannon turret with an Oerlikon KCA? Fixed forward-firing, for anti-tank work. I'd suggest a GAU-8, but that would probably be too big. Upgrade the nose turret to a 20mm M197, a la Cobra.

The 30mm chain gun would be a more than adequate replacement IMO.

This is an interesting page on the XM140 and its development.  Quite a powerful weapon, in itself it was designed more for APers than AT use, despite having a HEAT warhead.  http://translate.google.com.au/translate?hl=en&sl=auto&tl=en&u=http%3A%2F%2Fsobchak.wordpress.com%2F2010%2F01%2F05%2Fxm140-30mm-gun-xm30-xm52-xm120-armament-subsystems%2F

[Caveman]

Hey guys, thanks for the responses.

PR 19

It was SO far ahead of it's time that not much would have been changed I reckpon.
Some upward pointing anti-IR exhausts perhaps? If Westland-Agusta had anything to do with it, it'd have BERP rotor blades of course 
I'm not sure what that 'balancer cross beam' above the main rotor did, but maybe they'd have advanced the rotor deisgn so they didn't need it, and perhaps added a Longbow style radar-viewing dome above the rotor? How about a fenestron tail rotor, at least the sideways pointing one anyway. The underwing weapons would be more 'of the century' by now, but that's easily done. And maybe angled cockpit glass like the Marine's Cobras?

I think some sort of IR suppression would be a very good idea given its low level flight regime.
How about carson blades? or the steel swept tip jobs that the apaches use?
I had also thought about changing the tail rotor for a fenestron style one. Speed is really the raison de etre of this aircraft and I think that would be a good (in terms of streamlining) way to go. There may be some issues with the additional weight on the tail though.

rickshaw

A taller rotor mast, perhaps? 
Its sensors would have had to be seriously upgraded.  You'd see a FLIR, perhaps a Millimetre radar.  Armament would have changed - Hellfires, different rockets, its cannon would have changed to a chain gun more than likely.
Perhaps its biggest change would have been in tactics and employment.   It was designed to attack like an aircraft, nowadays, helicopters attack from the hover, popping up from behind cover to fire and then disappear again.   The Cheyenne was designed to attack at high speed, like an aircraft.  Effectively it was a gyrocopter, not a helicopter as a consequence.

I believe that it already had an infra red sight on it. The small turret under the nose directly beneath the gunners position contained an optical sight, laser range finder and IR IIRC. I agree that some sort of radar would be a must have upgrade. I completely agree on the armament front. I see it carrying a very similar suite as the apache. I think that the grenade launcher might be deleted.
I dont think that how you suggest current attack helicopters work is 100% accurate. Certainly my recent experience suggests that an attack is definitely made at speed and not in the hover...
I wonder how well the aircraft would have worked as a gyro? Is VTO really required?

ChernayaAkula

- chaff/flare launchers. Lots of 'em! If you look at the Israeli Apaches, they carry more weight in flares than in ammo!
- a DIRCM system as in the AMASE pods to protect against IR-guided munitions
- maybe that ducted fan for the pusher prop and a NOTAR-like set-up for the anti-torque tail rotor. Or dispense with the anti-torque tail rotor completely and use a co-axial main rotor.

I dont think that any aircraft currently on operations anywhere would reasonably be able to go about its business without a comprehensive defensive aids suite. I have a feeling that the additional drag of a taller mast and a second set of main rotors would be a much greater than that reduced by deleting the anti torque tail rotor.

RussC

A further rebuild of some airframes into drone systems following Sept. 11 01.

This is an interesting suggestion. Whilst I agree that drones have become very prevalent in recent times (possibly due to the events in 9/11) I havent seen many military aircraft which have been converted from piloted to drone versions. I am aware that the firescout at some point in its ancestry used to be a civii helicopter but i think the differences outweigh the similarities.

sandiego

I think a twin pack engine would be a logical choice.  All long serving helos increase in weight quite a bit with new sensors and weapons being added, and additional power is almost always needed.  Although original power was more than adequate, higher power would undoubedly been required eventually, and two engines can be better for survivabilty.  Quite a few helos have added an additional engine to deal with power demands (Cobra, CH53E, H-43, SeaSprite, etc).

Yes, I have had the Cobra -> Viper upgrade at the forefront of my mind for this. I think that two engines would be a logical choice. Even if 1 engine cant keep the aircraft in the air, it would at least provide power for hydraulics and electrical systems... (in order to get the aircraft to the scene of the crash)

Well. I think a lot of bits and pieces to think about/work on. I may well try and do a bit of a profile bash... Not sure when I will have the time though, such is life.

Thank you all for your comments guys

[rickshaw]

Are there any 1/72 injection moulded models of the Cheyenne?

[ChernayaAkula]

Yup. There was one by Aurora. 

<...>
ChernayaAkula

<...>
- maybe that ducted fan for the pusher prop and a NOTAR-like set-up for the anti-torque tail rotor. Or dispense with the anti-torque tail rotor completely and use a co-axial main rotor.

<...> I have a feeling that the additional drag of a taller mast and a second set of main rotors would be a much greater than that reduced by deleting the anti torque tail rotor.
<...>

Drag-wise, that's entirely possible. On the other hand, the co-axial rotor eliminates or at least lessens some problems associated with a conventional rotor (such as dissymetry of lift/retreating blade stall). The problem of retreating blade stall apparently also limits the possible top speed of a conventional helicopter.
And an anti-torque tail rotor has to be powered. Negate the need for this tail rotor and you either have more power for the main rotor or, in the Cheyenne's case, more power to the pusher prop.

[rickshaw]

I have a feeling that the additional drag of a taller mast and a second set of main rotors would be a much greater than that reduced by deleting the anti torque tail rotor.

My own reference to a taller rotor mast was because of the rumoured prospensity of the Cheyenne to hit its own tail with the main rotors when pulling up.   Contra-rotating blades would cure that but American designers have tended to shy away from such designs.

[Cobra]

if they Brought back the Cheyenne, i think it would be Better if they used the NOTAR system instead. Rickshaw, Kaman Helicopters uses Co-Axial Blades on their Copter,Including the K-MAX! Not Trying to Argue,just Trying to keep things Civil. Dan

[Caveman]

if they Brought back the Cheyenne, i think it would be Better if they used the NOTAR system instead. Rickshaw, Kaman Helicopters uses Co-Axial Blades on their Copter,Including the K-MAX! Not Trying to Argue,just Trying to keep things Civil. Dan

NOTAR does sound good in theory but I think in practice it has been found to be a bit lacking in control authority and is actually quite a power hungry system. Kaman prefer intermeshing rotor systems to co-ax but I don't think that they offer any less drag than co-ax. Interestingly I think they also utilise servo tabs for control but that's another point of discussion.

I'm not sure where I heard it from, I think it was the project canceled program on the Cheyenne. But at full speed only 20% of the engines power was being used by the main rotor. That can essentially be assumed to be the torque required. So there isn't a high demand for anti torque at high speed. Also, at high speeds aerodynamics are adequate to provide the torque reaction. So I think it's reasonable to assume negligible power requirements for the tail rotor at high speed...

[perttime]

Certainly my recent experience suggests that an attack is definitely made at speed and not in the hover...

That must surely depend on the terrain and what exactly you know about the enemy (location, weapons, does the enemy know you are there...).

Are you more likely to get a shot - and preferably survive - at speed in the open or hiding behind a hill and popping up to shoot?

[Caveman]

Certainly my recent experience suggests that an attack is definitely made at speed and not in the hover...

That must surely depend on the terrain and what exactly you know about the enemy (location, weapons, does the enemy know you are there...).

Are you more likely to get a shot - and preferably survive - at speed in the open or hiding behind a hill and popping up to shoot?

I completely agree! What do you know about the enemy? I would argue that you will rarely know enough to be happy hovering anywhere in range of a target of interest. Who else is hiding behind your hill? If you are moving the enemy can only ever know for certain where you have been.
As for what is the best for getting a shot off. In these days of 3rd party and gps targeting is that such an issue anymore?

[perttime]

If you are moving the enemy can only ever know for certain where you have been.
As for what is the best for getting a shot off. In these days of 3rd party and gps targeting is that such an issue anymore?

During my education in heavy mortars, a couple of decades back, I was told that WHEN the enemy finds out where I am, I can expect artillery shells arriving at my location in about a minute. So, I'd better be ready to move as soon as I'm done shooting.

I'd have no problems hitting a stationary target on the other side of a pretty big hill, with a dumb mortar. I'm not quite up to date about what options there are for hitting moving targets when you don't have line of sight.

[famvburg]

      Isn't Anigrand's resin kit injected as well? I'm thinking his kits are 'injected resin'.

Are there any 1/72 injection moulded models of the Cheyenne?

[Hobbes]

On the other hand, the co-axial rotor eliminates or at least lessens some problems associated with a conventional rotor (such as dissymetry of lift/retreating blade stall). The problem of retreating blade stall apparently also limits the possible top speed of a conventional helicopter.

Dissymmetry of lift, yes. The retreating blade stall problem still exists: after all, the blade still moves at the same speed relative to the air. So I don't expect a coax rotor system to be able to achieve higher speeds.

[Caveman]

On the other hand, the co-axial rotor eliminates or at least lessens some problems associated with a conventional rotor (such as dissymetry of lift/retreating blade stall). The problem of retreating blade stall apparently also limits the possible top speed of a conventional helicopter.

Dissymmetry of lift, yes. The retreating blade stall problem still exists: after all, the blade still moves at the same speed relative to the air. So I don't expect a coax rotor system to be able to achieve higher speeds.

Classically mu ( ratio of blade speed to forward speed) is considered a limit to rotary wing performance. But that is where one of the advantages of compound aircraft lie. If the rotors lift is offloaded onto fixed lifting surfaces then asymmetry of lift an blade stall become less significant. Especially for rigid rotor systems. Reference CarterCopter

[kitnut617]

Are there any 1/72 injection moulded models of the Cheyenne?

Yes --- if you can find one that isn't priced out of this world

http://www.oldmodelkits.com/index.php?detail=21904&searchtext=Cheyenne