The C-130 used to have the Alison/RR T-56-A-15 engine (4590 HP). The C-130J now uses the RR AE-2100 engine (4637 HP). Honeywell is now in late stage development of the T-55-714C (6000 HP).

"The latest configuration T55-714C delivers 22% more power and uses 8% less fuel than its predecessor. The next-generation T55 produces 6,000 SHP and is easier to maintain with lower operating costs and increased readiness for the warfighter."

Can anyone compare these engines?
How does a nextGen T-55 compare with an AE-2100?
Any reason the C-130J couldn't use the nextgen T55 (or even a derated version of that)?

https://aerospace.honeywell.com/us/en/l ... aft-engine

Isn't this a bit of a apples and oranges comparison? The RR AE-2100 is for fixed wing aircraft and the T55-714C is for rotorcraft.

aumaverick wrote:

Isn't this a bit of a apples and oranges comparison? The RR AE-2100 is for fixed wing aircraft and the T55-714C is for rotorcraft.

The T55 is always mounted horizontally. It's not like the engine would need a new orientation. I do wonder if the gearbox would need a new ratio.

USAF re-engines things when parts become an issue. That’s not the case for the legacy herc fleet. The T-56 has plenty of power for the Herc, and they don’t care one iota about fuel efficiency. Upgrading some E or H models to the RR might make sense, I dunno, at some point, but in today’s budget environment it is very far from a priority for what is basically an ANG/reserve fleet that works fine to fly the frames a few hours a month.

Tough to tout fuel efficiency against an engine that burns 1K an hour. Same idea with torque.

texl1649 wrote:

USAF re-engines things when parts become an issue. That’s not the case for the legacy herc fleet. The T-56 has plenty of power for the Herc, and they don’t care one iota about fuel efficiency. Upgrading some E or H models to the RR might make sense, I dunno, at some point, but in today’s budget environment it is very far from a priority for what is basically an ANG/reserve fleet that works fine to fly the frames a few hours a month.

It's not the engines that are the issue, but the propellers that are increasingly becoming obsolescent; most aircraft that are still using the T56 are switching to the 8-blade Collins NP2000 propellers with a digital Electronic Propeller Control System (EPCS).

Per the manufacturer's claims, it delivers a 20% thrust increase during take-off, a 50% reduction in maintenance time and a 20db sound reduction in the cockpit compared to legacy propeller systems. It is already being used on the E-2 Hawkeye and C-2 Greyhound fleet, and the USAF is already taking delivery of C-130H's upgraded with the NP2000's as well.

I'd like to know what happened to the proposal to put a more aerodynamic cockpit/nose section and winglets on the C-130 in addition to new engines ("advanced" or "next-gen" C-130 I think they were calling it) That cockpit glass is great for visibility but its the aerodynamic equivalent of a barn-door.

texl1649 wrote:

The T-56 has plenty of power for the Herc, and they don’t care one iota about fuel efficiency.

I bet they care about the payload/range chart, and the ability to carry more payload further is probably worth a whole bunch of iotas.

Longer maximum range, and for shorter range flights carrying less fuel means more payload. I agree it doesn't help with volume, just weight.

They probably also care about reduced maintenance cost, and lower burden on maintenance personnel.

But I do agree it's probably uneconomical .. depending on how long and how many hours you intend to fly the C-130s.

The C-130 will be getting replaced by a quad tilit rotor/wing in the JMR-Ultra program.

https://en.m.wikipedia.org/wiki/Future_Vertical_Lift

RJMAZ wrote:

The C-130 will be getting replaced by a quad tilit rotor/wing in the JMR-Ultra program.

https://en.m.wikipedia.org/wiki/Future_Vertical_Lift

Maybe. I doubt it but time will tell. I bet 20 years from now they are still flying more than 100 C-130s.

kitplane01 wrote:

I bet they care about the payload/range chart, and the ability to carry more payload further is probably worth a whole bunch of iotas.

Longer maximum range, and for shorter range flights carrying less fuel means more payload. I agree it doesn't help with volume, just weight.

They probably also care about reduced maintenance cost, and lower burden on maintenance personnel.

But I do agree it's probably uneconomical .. depending on how long and how many hours you intend to fly the C-130s.

No, they really don't. Because the powers that be are not fanboys. They're professionals (usually) on a fixed budget with many far, far higher priority programs to fund than squeezing a little more juice from an orange that fits their cup just fine as it is.

It's hard enough to replace their props, and that has a legit, service-identified, flight safety need.

kitplane01 wrote:

RJMAZ wrote:

The C-130 will be getting replaced by a quad tilit rotor/wing in the JMR-Ultra program.

https://en.m.wikipedia.org/wiki/Future_Vertical_Lift

Maybe. I doubt it but time will tell. I bet 20 years from now they are still flying more than 100 C-130s.

The C-130J has a service life of more than 20 years and there are still brand new C-130J coming off the production line. So of course there will be 100 C-130 still in service in 20 years time. That is like betting the sun will come up tomorrow.

To start a program today to put new engines on the C-130 would require production to go beyond 2040 to justify the development costs. The quad tilt rotor/wing would definitely be in production before then.

There is a huge push to bring heavier units straight to front line vertically. The forward operating bases can then be located much further from the front line exponentially reducing the logistics supply chain. The STOVL transport will replace one C-130, one helicopter and hundreds of personnel at the forward operating base protecting the runway, splitting the cargo from the C-130 into the helicopter. The STOVL takes the cargo in one step.

kitplane01 wrote:

aumaverick wrote:

Isn't this a bit of a apples and oranges comparison? The RR AE-2100 is for fixed wing aircraft and the T55-714C is for rotorcraft.

The T55 is always mounted horizontally. It's not like the engine would need a new orientation. I do wonder if the gearbox would need a new ratio.

And the original engine when used on the osprey develops 6000 hp. Allison/RR could easily bump the power on those 2100s if requested, but the roughly similar hp ratings between the H and J Herks is a feature, not a bug.

kitplane01 wrote:

aumaverick wrote:

Isn't this a bit of a apples and oranges comparison? The RR AE-2100 is for fixed wing aircraft and the T55-714C is for rotorcraft.

The T55 is always mounted horizontally. It's not like the engine would need a new orientation. I do wonder if the gearbox would need a new ratio.

The T55 would need a gearbox. The Chinook has the necessary reduction gearing built into the airframe, while with fixed-wing aircraft any gearing has to be provided as part of the engine.

RJMAZ wrote:

kitplane01 wrote:

RJMAZ wrote:

The C-130 will be getting replaced by a quad tilit rotor/wing in the JMR-Ultra program.

https://en.m.wikipedia.org/wiki/Future_Vertical_Lift

Maybe. I doubt it but time will tell. I bet 20 years from now they are still flying more than 100 C-130s.

The C-130J has a service life of more than 20 years and there are still brand new C-130J coming off the production line. So of course there will be 100 C-130 still in service in 20 years time. That is like betting the sun will come up tomorrow.

To start a program today to put new engines on the C-130 would require production to go beyond 2040 to justify the development costs. The quad tilt rotor/wing would definitely be in production before then.

There is a huge push to bring heavier units straight to front line vertically. The forward operating bases can then be located much further from the front line exponentially reducing the logistics supply chain. The STOVL transport will replace one C-130, one helicopter and hundreds of personnel at the forward operating base protecting the runway, splitting the cargo from the C-130 into the helicopter. The STOVL takes the cargo in one step.

You have much more trust the Army will get it right than I do.

I believe the original MV-22 program was for over 1,000 units, many of them Army units. The Comanche was supposed to go into production. Maybe the Army gets it right, but the vertical lift program seems SO uneconomical to me. And it's OK if you don't care about money, but my guess is that it will cost so much the Army will have to either cancel it or give up some other capability to afford it. Of course no one should be sure about the future ...

Spacepope wrote:

kitplane01 wrote:

aumaverick wrote:

Isn't this a bit of a apples and oranges comparison? The RR AE-2100 is for fixed wing aircraft and the T55-714C is for rotorcraft.

The T55 is always mounted horizontally. It's not like the engine would need a new orientation. I do wonder if the gearbox would need a new ratio.

And the original engine when used on the osprey develops 6000 hp. Allison/RR could easily bump the power on those 2100s if requested, but the roughly similar hp ratings between the H and J Herks is a feature, not a bug.

Sure. I understood that. I was really wondering of the three turbine engines that one might mount on a C-130, which can fly for the least weight in fuel while consuming the least maintenance.

kitplane01 wrote:

You have much more trust the Army will get it right than I do..

I think it will be a USAF program.

Here is a more recent article. Moving away from a fixed runway is very important.

https://www.airforcemag.com/air-force-c ... echnology/

"contractors have shown a variety of vertical-lift or short takeoff/vertical landing concepts"

I actually think a tilt wing like the LTV XC-142 prototype will win over a quad tilt rotor due to better slow takeoff and cruise performance. The tradeoff will be inferior hover efficiency. In a quad tilt rotor the rear engines might inhale hot exhaust gases from the front engines.

The Future Vertical Lift wiki page says engines up to 10,000hp are being studied. I assume that these powerful engines are for the largest aircraft which would be the C-130 replacement.

The XC-142 has four engines with 2,850 shp and a 15,637 kg vertical takeoff and 20,185 kg slow takeoff weights.

If we scale it up to four 10,000hp engines we end up with 54,720kg vertical takeoff and 70,647kg slow takeoff weights.

https://en.m.wikipedia.org/wiki/LTV_XC-142

kitplane01 wrote:

Spacepope wrote:

kitplane01 wrote:

The T55 is always mounted horizontally. It's not like the engine would need a new orientation. I do wonder if the gearbox would need a new ratio.

And the original engine when used on the osprey develops 6000 hp. Allison/RR could easily bump the power on those 2100s if requested, but the roughly similar hp ratings between the H and J Herks is a feature, not a bug.

Sure. I understood that. I was really wondering of the three turbine engines that one might mount on a C-130, which can fly for the least weight in fuel while consuming the least maintenance.

It’s likely those wimgs and engine mountings are stressed for that power rating, and any increase will result in added maint costs to structure. It’s doubtful there are any savings to be had.

Wouldn't new engines require a recertification of the airframe, new engine controls, and change to the avionics? This would essentially be a new variant of the H model requiring differences training as well? On top of all this, the new engine would also the aforementioned wings and engine mounts, gearbox, and a new supply chain? Throwing in a new powerful engine does not always mean more...well, maybe more $.

aumaverick wrote:

Wouldn't new engines require a recertification of the airframe, new engine controls, and change to the avionics? This would essentially be a new variant of the H model requiring differences training as well? On top of all this, the new engine would also the aforementioned wings and engine mounts, gearbox, and a new supply chain? Throwing in a new powerful engine does not always mean more...well, maybe more $.

Good example is the reengining of the B-52, a whole bunch of certification work made it cost prohibitive until the engine rebuilt cost tripled in 5 years time due to available parts drawdown.

New props make sense, but does the economics pencil out. Better to spend on fighter production then fixing something that is OK, not great.

Spacepope wrote:

kitplane01 wrote:

Spacepope wrote:

And the original engine when used on the osprey develops 6000 hp. Allison/RR could easily bump the power on those 2100s if requested, but the roughly similar hp ratings between the H and J Herks is a feature, not a bug.

Sure. I understood that. I was really wondering of the three turbine engines that one might mount on a C-130, which can fly for the least weight in fuel while consuming the least maintenance.

It’s likely those wimgs and engine mountings are stressed for that power rating, and any increase will result in added maint costs to structure. It’s doubtful there are any savings to be had.

It appears that this very problem is appearing on the Chinook, the current engines are 5,000 HP, the upgrade they can do goes to 6,000 HP. They have put on one Chinook engines with 7,500 HP but it appears that is "a bridge too far" ie the frame, drive system, gearbox do not have enough reserve for a 50% HP increase, but can be massaged, probably with lower hours / cycles, a 20% increase.

The C-130 payload-range curve is pretty good already, suitable for TATL, Europe to the Middle East or even NZ to Antarctica. If you need even more range, you can add external fuel tanks. It's nearly perfect as a tactical (intra-theater) airlifter and can still do the occasional longer mission.

Much like the CH-47 reengine, you'd be spending billions of $ on a capability that would be useful in 0.001% of potential missions.

mxaxai wrote:

The C-130 payload-range curve is pretty good already, suitable for TATL, Europe to the Middle East or even NZ to Antarctica. If you need even more range, you can add external fuel tanks. It's nearly perfect as a tactical (intra-theater) airlifter and can still do the occasional longer mission.

Much like the CH-47 reengine, you'd be spending billions of $ on a capability that would be useful in 0.001% of potential missions.

If you need more range you use a C-17.

RJMAZ wrote:

kitplane01 wrote:

You have much more trust the Army will get it right than I do..

I think it will be a USAF program.

[...]

The Air Force has essentially zero expertise (and, currently, interest) in rotorcraft. The Army has its hands full with FARA/FLRAA right now, and a C-130-scale tilt-rotor/tilt-wing would be technically very risky. It's not just a matter of scaling what has been done already.

IADFCO wrote:

The Air Force has essentially zero expertise (and, currently, interest) in rotorcraft. The Army has its hands full with FARA/FLRAA right now, and a C-130-scale tilt-rotor/tilt-wing would be technically very risky. It's not just a matter of scaling what has been done already.

This is completely different to the Army programs. The USAF is only years away from putting out an RFP for a VTOL C-130 replacement.

The AFWERX innovation hub last year showed all of the proposals. All major OEMs including all engine manufacturers are involved and have been working on their proposals for years. It is now down to 11 contenders. Like previous programs we will probably see two winners selected next year that will produce prototypes.

The Lockheed tilt wing proposal is by far the most low risk. Designs will score points for reduced radar cross section.

The Bell designs look absolutely amazing! There are similarities with the F-35B lift system but instead of a lift fan it power a tilt rotor. The tilt rotors fold away during cruise and the turbofan in the fuselage provides the thrust. The Bell design being scalable to "45,359 kg" to me points towards a design with two off the shelf F-135 engines from the F-35B mounted on either side of the cargo bay. While the F-35B lift system can only lift 18,600kg vertically the bigger rotor area would provide much more lift than the F-35B lift fan while using the same shaft power.

https://evtol.news/news/air-force-picks ... ol-program

https://www.defensenews.com/air/2021/09 ... ter-stage/

One thing is for certain there is zero chance the C-130 will get new engines. If the 6th gen fighter program is anything to go by the USAF went from developing requirements to a secretly flown aircraft to the F-22 retirement announcement all in a very short period.

I could definitely still see old C-130J in the ANG units in 40 years time. Some of the VTOL designs looks extremely expensive.

LyleLanley wrote:

If you need more range you use a C-17.

Exactly. Or you send a tanker with them, or ask an ally to provide an A400M or C-2.

Unless you're the USCG or similar niche applications where range is more important than payload, but you can't afford dedicated long-range aircraft. Nobody's going to invest lots of money for that use case, so add-on tanks will have to suffice.

RJMAZ wrote:

IADFCO wrote:

The Air Force has essentially zero expertise (and, currently, interest) in rotorcraft. The Army has its hands full with FARA/FLRAA right now, and a C-130-scale tilt-rotor/tilt-wing would be technically very risky. It's not just a matter of scaling what has been done already.

This is completely different to the Army programs. The USAF is only years away from putting out an RFP for a VTOL C-130 replacement.

The AFWERX innovation hub last year showed all of the proposals. All major OEMs including all engine manufacturers are involved and have been working on their proposals for years. It is now down to 11 contenders. Like previous programs we will probably see two winners selected next year that will produce prototypes.

The Lockheed tilt wing proposal is by far the most low risk. Designs will score points for reduced radar cross section.

The Bell designs look absolutely amazing! There are similarities with the F-35B lift system but instead of a lift fan it power a tilt rotor. The tilt rotors fold away during cruise and the turbofan in the fuselage provides the thrust. The Bell design being scalable to "45,359 kg" to me points towards a design with two off the shelf F-135 engines from the F-35B mounted on either side of the cargo bay. While the F-35B lift system can only lift 18,600kg vertically the bigger rotor area would provide much more lift than the F-35B lift fan while using the same shaft power.

https://evtol.news/news/air-force-picks ... ol-program

https://www.defensenews.com/air/2021/09 ... ter-stage/

One thing is for certain there is zero chance the C-130 will get new engines. If the 6th gen fighter program is anything to go by the USAF went from developing requirements to a secretly flown aircraft to the F-22 retirement announcement all in a very short period.

I could definitely still see old C-130J in the ANG units in 40 years time. Some of the VTOL designs looks extremely expensive.

None of this sounds like an efficient way to transport goods. The day-to-day mission of the military transport is from runway to runway, and 3x the cost to land in a field instead of a runway might not be winning except in a few use cases. Reminder: money not spent on super-high-tech transports can be spent on weapons, or soldiers.

After advocating to spend billions of dollars reengining an airplane that doesn't need it and would never get a positive RoI, now you bring up efficiency?

If you want efficient transportation of goods go to FedEx or UPS. Of course, they don't worry about being shot at, tossing crap out of the back, low levels, air refueling, heavily armed passengers, or landing on a target with scant diverts for hundreds of miles. Delivering a tank or 150K of ammo isn't the same as delivering porn and amazon packages. Such is life.

Reminder: a super high-tech transport is a weapon!

A transport with acceptable STOL, that can move significant (higher, heavier) vehicles up to 30t and can cross the Atlantic with 20t, refuel fighter & helicopters , seems a better investment moving forward, than rebuilding a 60 year old design.

The good old Herc has been limiting US army/ marines options for a long time. Overwhelmingly political- industrial driven.

https://quotulatiousness.ca/blog/2013/0 ... -politics/

kitplane01 wrote:

None of this sounds like an efficient way to transport goods. The day-to-day mission of the military transport is from runway to runway, and 3x the cost to land in a field instead of a runway might not be winning except in a few use cases. Reminder: money not spent on super-high-tech transports can be spent on weapons, or soldiers.

The C-130 doesn't sound like an efficient way to transport goods either. You are paying 3x the cost per kg of freight to have STOL and gravel runway performance with the C-130J. It might not be winning except in a few use cases.

The USAF uses 767F, 777F and 747F on a daily basis for air freight. The civilian contractors have sized their fleet and purchased dozens of extra aircraft to handle the massive freight loads of the USAF. There is also hundreds of additional civilian trucks to handle the huge volumes of day to day military freight.

The US has been increasing its use of civilians freight operators as it provides massive cost savings. The military aircraft purchased should then focus on war. To reduce the exposure to the supply line. VTOL takes center stage.

https://www.defensenews.com/air/2021/09 ... ter-stage/

You don't want a C-130 landing at a forward operating base to split the cargo into smaller helicopters to send to the front line. You then need a second C-130 flight just to bring in fuel for the helicopters and a third C-130 flight for food for the helicopter crew and base staff. The three C-130 aircraft could be replaced with one high speed VTOL aircraft that takes the cargo straight to the front line eliminating the entire forward operating base. Now that is what I call efficiency.

Forward operating bases would be vulnerable to cruise missile attack against a moderately equipped enemy. This fear is driving the high speed VTOL program.

Remember fuel costs depends on where you get it. Fuel cost from an inflight refueling tanker might be 10 times the original cost per litre. Cost of fuel at a forward operating base could be 100 times the cost per litre. So fuel efficiency of the VTOL transport isn't important.

keesje wrote:

A transport with acceptable STOL, that can move significant (higher, heavier) vehicles up to 30t and can cross the Atlantic with 20t, refuel fighter & helicopters , seems a better investment moving forward, than rebuilding a 60 year old design.

The US is reducing the number of types. Purchasung the A400M is just providing excessive overlapping capabilities. The A400M cant fly as far as a C-17. The A400M can't land on a runway as short as the C-130J. The A400M can however do the majority of missions from both types.

The USAF in 40 years will most likely operate only two cargo aircraft. One large strategic airlifter and one fancy VTOL tactical airlifter.

RJMAZ wrote:

kitplane01 wrote:

None of this sounds like an efficient way to transport goods. The day-to-day mission of the military transport is from runway to runway, and 3x the cost to land in a field instead of a runway might not be winning except in a few use cases. Reminder: money not spent on super-high-tech transports can be spent on weapons, or soldiers.

The C-130 doesn't sound like an efficient way to transport goods either. You are paying 3x the cost per kg of freight to have STOL and gravel runway performance with the C-130J. It might not be winning except in a few use cases.

The USAF uses 767F, 777F and 747F on a daily basis for air freight. The civilian contractors have sized their fleet and purchased dozens of extra aircraft to handle the massive freight loads of the USAF. There is also hundreds of additional civilian trucks to handle the huge volumes of day to day military freight.

The US has been increasing its use of civilians freight operators as it provides massive cost savings. The military aircraft purchased should then focus on war. To reduce the exposure to the supply line. VTOL takes center stage.

https://www.defensenews.com/air/2021/09 ... ter-stage/

You don't want a C-130 landing at a forward operating base to split the cargo into smaller helicopters to send to the front line. You then need a second C-130 flight just to bring in fuel for the helicopters and a third C-130 flight for food for the helicopter crew and base staff. The three C-130 aircraft could be replaced with one high speed VTOL aircraft that takes the cargo straight to the front line eliminating the entire forward operating base. Now that is what I call efficiency.

Forward operating bases would be vulnerable to cruise missile attack against a moderately equipped enemy. This fear is driving the high speed VTOL program.

Remember fuel costs depends on where you get it. Fuel cost from an inflight refueling tanker might be 10 times the original cost per litre. Cost of fuel at a forward operating base could be 100 times the cost per litre. So fuel efficiency of the VTOL transport isn't important.

I agree with everything you wrote.

But ...

A C-130 costs $8000/hour to fly. A Chinook is $6000/hour to fly.

An MV-22 is $18,000/hour to fly, and an aircraft twice the size of an MV-22 might cost $36,000/hour to fly. That's about 5x of a Chinook or C-130!

(Yes, of course no one knows how much the unbuilt aircraft will cost to fly. Plane costs don't always scale linearly with size, and again it is just's a rough estimate.)

A forward operating base might cost $100,000 an hour. If the tactical VTOL transport eliminates this cost then it is far cheaper than any C-130 and Chinook combo.

Let's look at the Iraq war. For every soldier walking the streets there might be 10 other military personnel in Iraq supporting that soldier. The helicopters and the entire maintenance crew were in Iraq. The fuel was trucked in and the bases and fuel transports all needed protection.

The same Iraq war with VTOL tactical transports and V-22/280 aircraft would have eliminated all aircraft based in Iraq. They could have operated safely in Kuwait, Turkey and Saudi Arabia. The amount of fuel used in theatre would have been massively reduced. For every soldier walking the streets you might have less than 3 military personnel supporting that soldier.

A typical patrol mission in Iraq involved soldiers driving in a few light armoured vehicles 50+ km away from their main base in Iraq. A VTOL tactical transport could have dropped them off with their vehicles in the morning and picked them up in the evening. Then safely gone back to the base in Turkey/Kuwait/Saudi Arabia. Any point in Iraq is within 500kms of airport in Turkey, Saudi Arabia or Kuwait. So we are looking at a maximum of 30 minutes flight time. These VTOL tactical aircraft could cost as much as an F-22 and they will still buy hundreds of them as the savings are massive in any conflict.

A Chinook wouldn't have the range to bring in the vehicles like this. The slow speed of the Chinook puts the flight times above one hour massively reducing the number of vehicles it can insert and pickup per day. A Chinook would also be vulnerable to MANPADS the entire flight.

One VTOL tactical aircraft might be able to insert 20 Light Tactical Vehicles in a single day. 10 trips with 2 vehicles per trip. You might need 6 Chinooks to do the same with 3 trips each and one vehicle per trip. This is clearly not feasible.

RJMAZ wrote:

A forward operating base might cost $100,000 an hour. If the tactical VTOL transport eliminates this cost then it is far cheaper than any C-130 and Chinook combo.

Let's look at the Iraq war. For every soldier walking the streets there might be 10 other military personnel in Iraq supporting that soldier. The helicopters and the entire maintenance crew were in Iraq. The fuel was trucked in and the bases and fuel transports all needed protection.

The same Iraq war with VTOL tactical transports and V-22/280 aircraft would have eliminated all aircraft based in Iraq. They could have operated safely in Kuwait, Turkey and Saudi Arabia. The amount of fuel used in theatre would have been massively reduced. For every soldier walking the streets you might have less than 3 military personnel supporting that soldier.

A typical patrol mission in Iraq involved soldiers driving in a few light armoured vehicles 50+ km away from their main base in Iraq. A VTOL tactical transport could have dropped them off with their vehicles in the morning and picked them up in the evening. Then safely gone back to the base in Turkey/Kuwait/Saudi Arabia. Any point in Iraq is within 500kms of airport in Turkey, Saudi Arabia or Kuwait. So we are looking at a maximum of 30 minutes flight time. These VTOL tactical aircraft could cost as much as an F-22 and they will still buy hundreds of them as the savings are massive in any conflict.

A Chinook wouldn't have the range to bring in the vehicles like this. The slow speed of the Chinook puts the flight times above one hour massively reducing the number of vehicles it can insert and pickup per day. A Chinook would also be vulnerable to MANPADS the entire flight.

One VTOL tactical aircraft might be able to insert 20 Light Tactical Vehicles in a single day. 10 trips with 2 vehicles per trip. You might need 6 Chinooks to do the same with 3 trips each and one vehicle per trip. This is clearly not feasible.

I understand what you're saying .. but I'm not sure I agree. The point is not to conduct the patrol, the point is to win the war. If the nation is so hostile, and our military presence is so weak, we cannot secure an FOB and we cannot drive a patrol 50km , then we've already lost.

kitplane01 wrote:

I understand what you're saying .. but I'm not sure I agree. The point is not to conduct the patrol, the point is to win the war. If the nation is so hostile, and our military presence is so weak, we cannot secure an FOB and we cannot drive a patrol 50km , then we've already lost.

It is not that black and white.

We didn't see the USAF base their C-5 and C-17 squadrons in Iraq. They dropped off and picked up when required. This strategy simply moves further down the logistics and supply chain.

Every soldier guarding a forward operating base or protecting a fuel truck convoy is one less soldier to help win the war on the front line. So moving the bulk of the logistics out of theatre is improving the size of the combat force on the front line.

Improving logistics is only one advantage of the VTOL. Then we have the mounted vertical maneuver concept which has been discussed many times. Being able to place armoured units at any point in the battlefield is very difficult for an enemy to defend.

RJMAZ wrote:

kitplane01 wrote:

I understand what you're saying .. but I'm not sure I agree. The point is not to conduct the patrol, the point is to win the war. If the nation is so hostile, and our military presence is so weak, we cannot secure an FOB and we cannot drive a patrol 50km , then we've already lost.

It is not that black and white.

We didn't see the USAF base their C-5 and C-17 squadrons in Iraq. They dropped off and picked up when required. This strategy simply moves further down the logistics and supply chain.

Every soldier guarding a forward operating base or protecting a fuel truck convoy is one less soldier to help win the war on the front line. So moving the bulk of the logistics out of theatre is improving the size of the combat force on the front line.

Improving logistics is only one advantage of the VTOL. Then we have the mounted vertical maneuver concept which has been discussed many times. Being able to place armoured units at any point in the battlefield is very difficult for an enemy to defend.

I agree with almost everything you wrote. The question is "is this the best use of the money". Because not buying the VTOL would let you pay more soldiers, or more weapons, or so on.

I don't think any of the VTOLs are going to fly in armored vehicles bigger than an MRAP. Especially not the new AFVs that weight 40 tons. A Stryker might weight 20 tons, but a Boxter weighs 38, and a Namer weighs 60.

RJMAZ wrote:

Every soldier guarding a forward operating base or protecting a fuel truck convoy is one less soldier to help win the war on the front line.

I think that here is the bulk of the misunderstanding.
The front line as you call it doesn't really exists in an asymmetrical war, the US don't need the extra two boots on the ground to defeat the Iraki army. They really can do it without flinching with tec from the 70s...

After this first phase, the FOB becomes the Frontline, that is what you need to be as close as possible to the citizen, protect them from terror attacks, gain their trust, establish good relationships etc...

What you are describing is great for special ops, but to "win a war" like Irak or Afghanistan, you actually need more FOBs and 50k patrols than day long insertions. The goal of the patrol is not to get there but to actually patrol the ground and make it safer for everyone by there mere presence

Naincompetent wrote:

I think that here is the bulk of the misunderstanding.
The front line as you call it doesn't really exists in an asymmetrical war, the US don't need the extra two boots on the ground to defeat the Iraki army. They really can do it without flinching with tec from the 70s...

After this first phase, the FOB becomes the Frontline, that is what you need to be as close as possible to the citizen, protect them from terror attacks, gain their trust, establish good relationships etc...

This work would still be done. There would still be bases in Iraq but the logistics would be massively reduced. The helicopter pilots, military chefs and runway maintenance crew are not out in the field establishing relationships.

Each FOB could be 10% of the size, be much easier to defend and still maintain the same presence. Not all of the soldiers out in the field need to return to a FOB to sleep at night. Most could easily cross the border and have their vehicle picked up by a VTOL aircraft. A 1 hour drive to the FOB is replaced with a 30 minute VTOL flight.

The armoured patrols leaving the FOB were also extremely predictable. Having completely random insertions of these patrols makes it hard for the enemy to place IED's.

As fuel in theatre was so expensive lighter more fuel efficient vehicles were used and they were much more vulnerable to IEDs.

RJMAZ wrote:

Naincompetent wrote:

I think that here is the bulk of the misunderstanding.
The front line as you call it doesn't really exists in an asymmetrical war, the US don't need the extra two boots on the ground to defeat the Iraki army. They really can do it without flinching with tec from the 70s...

After this first phase, the FOB becomes the Frontline, that is what you need to be as close as possible to the citizen, protect them from terror attacks, gain their trust, establish good relationships etc...

This work would still be done. There would still be bases in Iraq but the logistics would be massively reduced. The helicopter pilots, military chefs and runway maintenance crew are not out in the field establishing relationships.

Each FOB could be 10% of the size, be much easier to defend and still maintain the same presence. Not all of the soldiers out in the field need to return to a FOB to sleep at night. Most could easily cross the border and have their vehicle picked up by a VTOL aircraft. A 1 hour drive to the FOB is replaced with a 30 minute VTOL flight.

The armoured patrols leaving the FOB were also extremely predictable. Having completely random insertions of these patrols makes it hard for the enemy to place IED's.

As fuel in theatre was so expensive lighter more fuel efficient vehicles were used and they were much more vulnerable to IEDs.

I agree that there’s a misunderstanding here. What you’re describing is more of a hit and run style patrol, just dropping in wherever and patrolling around for a few hours, then getting airlifted back to base. That doesn’t win you a war or earn trust from the people you’re trying to protect.

If I’m looking to attack some village or town, I simply wait a few hours after I last saw the patrol go by when I’m reasonably certain they’ve been airlifted out and are now a few hundred miles away. Or I attack the next day when that patrol has been redeployed elsewhere. Sure they can redeploy and airlift them over to where I’m attacking, but by that point a few hours have gone by, and I’m long gone. Or I shoot down the massive tilt rotor and have more time.

A quad Herc-sized aircraft I think will happen, but I doubt it will be just VTOL (unless mostly empty), as you’ll need a football size area anyway and realistically the down wash would/will be tremendous, especially for an unimproved field/strip etc. The political battle for it between the army and USAF will be…unfortunate and likely cost at least 10 years of squabbling, which will lead to…more a.net bickering about ongoing C-130 production thru the 2050’s.

texl1649 wrote:

A quad Herc-sized aircraft I think will happen, but I doubt it will be just VTOL (unless mostly empty), as you’ll need a football size area anyway and realistically the down wash would/will be tremendous, especially for an unimproved field/strip etc. The political battle for it between the army and USAF will be…unfortunate and likely cost at least 10 years of squabbling, which will lead to…more a.net bickering about ongoing C-130 production thru the 2050’s.

A C-130-size VTOL is certainly conceivable, but it would require the use of many technologies that are unproven, or at least unproven at that scale. Some things don't scale easily. Several years ago NASA carried out an extensive investigation on what a 90 passengers/1000 nm/300 kts VTOL could look like (google, or better, duckduckgo "NASA LCTR Large Civil Tilt Rotor" for many links), and this became painfully obvious. Impossible? No, but it would require such massive R&D investments that, at least in the US, it is essentially a nonstarter.

texl1649 wrote:

A quad Herc-sized aircraft I think will happen, but I doubt it will be just VTOL (unless mostly empty), as you’ll need a football size area anyway and realistically the down wash would/will be tremendous, especially for an unimproved field/strip etc. The political battle for it between the army and USAF will be…unfortunate and likely cost at least 10 years of squabbling, which will lead to…more a.net bickering about ongoing C-130 production thru the 2050’s.

All the designs suggest it will be STOVL like a V-22 and F-35B.

The V-22 can only takeoff vertical with approximately 50% fuel and 50% payload. The convenient think about STOVL is usually the tactical airlift mission starts from a full size runway. So the aircraft can take off with extra fuel and it's not really a negative. The aircraft will then burn fuel/weight on the way to the front line where it is now light enough to land vertical. It then has enough fuel to do the return trip and with the payload dropped off it can do a rapid tactical takeoff.

This is why the tilt wing idea is my favourite. It gives the biggest payload boost when doing a rolling takeoff or landing on say a soccer field area.

The battle between the USAF and Army will definitely be difficult. This USAF program has massive overlap with the Army JMR-ultra program. There is no chance both programs could produce two aircraft. Both programs are looking at a very similar size but the USAF clearly has higher speed requirements. A tilt wing design is definitely more of a USAF aircraft but a quad tilt rotor is definitely something that could be operated by the Army.

I think a VTOL transport would be considerable be more expensive than a conventional 4 engined transport. And carry less, have shorter range and fly slower.
https://www.businessinsider.com/see-ins ... &r=US&IR=T

keesje wrote:

I think a VTOL transport would be considerable be more expensive than a conventional 4 engined transport. And carry less, have shorter range and fly slower.
https://www.businessinsider.com/see-ins ... &r=US&IR=T

Though the 20 year old Bell Boeing model/concept is outdated now, clearly the concept of deployment/employment of a quad tiltrotor is still interesting to consider.

https://youtu.be/DJovLfFmOB4

https://en.wikipedia.org/wiki/Talk:Bell ... _TiltRotor

Not trying to derail the thread, but this (type of capability) is what any future C-130 upgrade considerations will be weighed against.

texl1649 wrote:

Not trying to derail the thread, but this (type of capability) is what any future C-130 upgrade considerations will be weighed against.

I think there's a new, less risky, less theoretical NATO benchmark these days. https://preview.redd.it/xkdbl0z0kiu11.j ... 1da451779b

keesje wrote:

I think a VTOL transport would be considerable be more expensive than a conventional 4 engined transport.

No one is disputing it will be more expensive to buy.

If someone invented a teleporting machine that could send cargo to any point on Earth no one would compare the price of that machine to a conventional 4 engine transport. The entire strategic, tactical and helicopter transport fleets would become redundant.

keesje wrote:

And carry less, have shorter range and fly slower.

Than what? I'm sure it will be bigger, longer ranged and faster than a C-27J. What is the perfect size/spec? I'm sure you think the A400M spec is perfect.

I would say the requirement should be to land vertical with a single 20t armoured "stryker class" vehicle. It should have a cargo bay just long enough to fit two 10t tactical vehicles. With enough fuel to return 500nm. This should handle the movement of fast and agile forces. Though the US could decide that it should be able to fit a heavier 30t Bradley fighting vehicle.

The Bell proposals are clearly showing designs that would be faster than any turboprop transport.

I think the VTOL transports never left the powerpoints during th elast 20 years, and there's good reason for that.


https://www.flightglobal.com/heavy-duty ... 31.article

They'll probably cost $.5B a ship, be noisy, expensive to operate, vunerable and awesome.
But Awesome doesn't replace hundreds of Hercs. Look at B2, F22, Osprey's and other awesome's.

As others mentioned the downwash/ brownout of a 60-70t VTOL also must huge. Twice a CH53K with a 30t load?
The XC-142A was skipped for that reason 60 yrs ago.. https://www.thedrive.com/the-war-zone/3 ... dust-cloud

.

744SPX wrote:

I'd like to know what happened to the proposal to put a more aerodynamic cockpit/nose section and winglets on the C-130 in addition to new engines ("advanced" or "next-gen" C-130 I think they were calling it) That cockpit glass is great for visibility but its the aerodynamic equivalent of a barn-door.

Isn't that an A400M?

RJMAZ wrote:

keesje wrote:

I think a VTOL transport would be considerable be more expensive than a conventional 4 engined transport.

No one is disputing it will be more expensive to buy.

If someone invented a teleporting machine that could send cargo to any point on Earth no one would compare the price of that machine to a conventional 4 engine transport. The entire strategic, tactical and helicopter transport fleets would become redundant.

I would.

It depends on economics. It might be that teleporting dying soldiers from the battlefield to the hospital was an economic use, and teleporting water bottles to the base was not. "Economics don't matter" is silly (and not what you wrote). "Economics matter less than you people think" depends on currently unknown numbers. But yes, we should try and dream and advance and make progress.

If it was me, I'd consider loitering munitions a better economic bet than large VTOL transports. But was can do two things at once.

@keesje -- thanks for the slide -- very interesting

keesje wrote:

[...]

As others mentioned the downwash/ brownout of a 60-70t VTOL also must huge. Twice a CH53K with a 30t load?
The XC-142A was skipped for that reason 60 yrs ago.. https://www.thedrive.com/the-war-zone/3 ... dust-cloud

.

It is possible to estimate the downwash at the rotor disk in hover using momentum theory. The formula is v = sqrt(T/2 rho A), where v is the downwash at the rotor disk in ft/sec, T is the rotor thrust in lbs, rho is the air density, and A is the rotor disk area. So, for T=130Klbs and A=4K sq ft (rotor radius of about 36 ft), it is v=sqrt(130,000/2*0.002378*4000) = 82.7 ft/sec or about 49 kts.

Knowing the downwash, it is also possible to estimate the power P required to hover, which is P=Tv/550 HP. For this example, P = 130,000*82.7/550 = 19,538 HP. This is the "ideal" power. To get the actual rotor power required to hover one needs to divide by 0.75/0.8 and add other mechanical losses, so a more realistic result is 26-27K HP.

By the way, this shows the performance penalty intrinsic in tilt rotors. To reduce the power required we need to reduce the downwash, and therefore increase the disk area. So, to hover efficiently we need big rotors, but when the rotors are turned 90 degrees and become propellers, they become inefficient. The VDTR (Variable Diameter Tilt Rotor) was proposed by NASA and Sikorsky to address this issue, but never made it beyond the wind tunnel stage. This is an example of technologies that could help achieve a fast, efficient VTOL transport, but are still untested in actual flying hardware.