JMR (Joint Multi-Role) & FVL (Future Vertical Lift) Programs

TomcatViP said:
Don't forget that vertical flight is all about Mass Vs Power. A reduced cross section fuselage is also lighter and offers generally less drag, something that ease keeping/increasing performances with a significant military payload when the range induces a need for a greater magazine. Think also agility transitioning in and out vertical mode. You certainly don't want to be stuck with a sluggish airframe while being shot at.
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You also wouldn't want a scenario repeating as per Afghanistan where the AH-64s couldn't keep up with the CH-47s. I expect the USMC has a similar conundrum given the V-22 can fly so much further and faster than the AH-1s. So an associated gunship version that dropped some weight but maintained or even gained a bit of speed would be advantageous.
 
e-Graphite said:
But to what end? No need for lower drag. Reduced vulnerability to ground fire during direct attack is unlikely to be the reason as the wing/nacelles stay the same and I really doubt we'll see one with a 30 mm cannon taking on tanks. A modern, dedicated attack tiltrotor is more likely to be a modified fuselage with a large internal capacity of ALE and weapons to be ejected through the sides/bottom of the fuselage with that extra weight paid for by removing external load capabilities, troop provisions/protection, etc. I suspect we'll see some basic weapons hard points on the wings of all FLRAA, but I would expect more out of a dedicated attack ship.
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Vertical drag is still an issue.

A gunship V280 doesn't need the entire passenger compartment filled with ALEs. At best it needs about half that volume, maybe less. Not that it couldn't use the entire depth of the fuselage under the wings if ALEs just drop out instead of launch off rails or tubes. But all it needs is to make sure the launch rails/tubes clear the proprotors even in full forward flight.


Ozair said:
You also wouldn't want a scenario repeating as per Afghanistan where the AH-64s couldn't keep up with the CH-47s. I expect the USMC has a similar conundrum given the V-22 can fly so much further and faster than the AH-1s. So an associated gunship version that dropped some weight but maintained or even gained a bit of speed would be advantageous.
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Exactly.

The escort craft needs to be faster than the troop transports when the escort craft is fully loaded.
 
Drag is a very big issue. Especially when having to go long distances. Drag is exponentially increased with speed so going twice the speed induces > 2x drag. IF I can carry the same weapons load internally, and not exposing the weapons to environmental effects at high speed and long duration, while not incurring the associated drag with external weapons, why would I not carry them internally. A practical demonstration of this can be to compare a UH-60M and an MH-60M (DAP). The DAP is several tens of knots slower than the "slick" Blackhawk, both due to weight, but more so the drag associated with all of the scabbed-on sensors and weapons.
The reasons the venerable Chinook can go faster than any other U.S. Army is installed power, and it has very little drag because everything is inside. When it does sling loads the Apache's are faster.
 
yasotay said:
Drag is a very big issue. Especially when having to go long distances. Drag is exponentially increased with speed so going twice the speed induces > 2x drag. IF I can carry the same weapons load internally, and not exposing the weapons to environmental effects at high speed and long duration, while not incurring the associated drag with external weapons, why would I not carry them internally. A practical demonstration of this can be to compare a UH-60M and an MH-60M (DAP). The DAP is several tens of knots slower than the "slick" Blackhawk, both due to weight, but more so the drag associated with all of the scabbed-on sensors and weapons.
The reasons the venerable Chinook can go faster than any other U.S. Army is installed power, and it has very little drag because everything is inside. When it does sling loads the Apache's are faster.
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Which is why I suggested internal weapons carriage in the existing fuselage. Sure, you COULD develop a custom fuselage, but it'll need to hit similar landing gear hard points and empennage arrangements to reduce development risk. The stiffness of the fuselage needs to be similar to the existing one, the same avionics, mission equipment, APU, etc. all need to be carried. Seems like a lot of cost for a small payoff.
 
Weapons are denser than bodies. Hence, the available volume is not what affects the performances but the fact that your attack version will be heavier. By reducing the drag and empty mass of the fuselage, you free some available power to tackle that extra weapon load in dynamic conditions. And weapon engagements are all about dynamics.

Remember the AH-1. She came years after the successful usage of armed UH-1 and still, it was widely seen as an improvement in all regards.

There is also another factor that make me feel uncomfortable with a converted transport helo: the cargo bay used as a weapon bay isn't generally protected to contain secondary deflagration. See by yourself:

View: https://youtu.be/vVAjnAU-Bps
 
TomcatViP said:
Weapons are denser than bodies. Hence, the available volume is not what affects the performances but the fact that your attack version will be heavier. By reducing the drag and empty mass of the fuselage, you free some available power to tackle that extra weapon load in dynamic conditions. And weapon engagements are all about dynamics.

Remember the AH-1. She came years after the successful usage of armed UH-1 and still, it was widely seen as an improvement in all regards.

There is also another factor that make me feel uncomfortable with a converted transport helo: the cargo bay used as a weapon bay isn't generally protected to contain secondary deflagration. See by yourself:
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A fair set of points. I will go one further to say that (I am told) the fuselage is far less to develop, cost wise, than the dynamic components. If you can retain the same ~ 80% commonality resident on the current USMC H-1 series, it might be worth the investment. I am just not sure that the cost is worth the investment. Not to mention that the second and third order effects of commonality might argue for as much commonality as is possible.
A perennial argument to be sure.
 
yasotay said:
A fair set of points. I will go one further to say that (I am told) the fuselage is far less to develop, cost wise, than the dynamic components. If you can retain the same ~ 80% commonality resident on the current USMC H-1 series, it might be worth the investment. I am just not sure that the cost is worth the investment. Not to mention that the second and third order effects of commonality might argue for as much commonality as is possible.
A perennial argument to be sure.
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I mean, using the entire wing and tail surfaces, maybe the tail boom up to where it expands to the passenger compartment, would give you much of the commonality you're talking about. That's about how much the H-1Y/Z have in common. Oh, and landing gear.

I'd want a narrower fuselage so that weapons-bay-door-mounted weapons like on Comanche would clear the proprotors in full forward flight.
 
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The Way Ahead with FLRAA: Insights from AUSA 2024 - Second Line of Defense

By Robbin Laird The panel on the future of vertical lift and interviews conducted by the press during the recent AUSA conference provided further insights regarding the FLRAA program and the way ahead. The conference was held from the 14-16 October in Washington D.C. Let us address first the...
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A somewhat longer article, but gives you an idea of some of the efforts that the U.S. Army is using to prepare for the arrival of the FLRAA.

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The U.S. Army Approach to its New Tiltrotor Aircraft - Second Line of Defense

By Robbin Laird FLRAA is coming at the dawn of the age of autonomous systems. It is being crafted as a manned program to operate in the con-ops of formations that will operate in the world of combined arms operations of manned systems working with autonomous ones. The Army approach encompasses...
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Also more insights in how the U.S. Army will integrate the aircraft into the force structure.
 
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