China's transport, tanker & heavy lift aircraft

xyqq said:

PLAA has been quite serious about putting a boom system on Y-20:
View attachment 61101
It suites a relatively large plane, which can experience tremendous difficulty in catching a floating "basket". That is probably why there is only one KJ-500 with an experimental probe installed.
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I have no doubt they are seriously looking into it after all it’s easy to turn a boom into a Basket but it’s a hell of a lot harder to turn a probe into a receiver.
As you and I have shown there are Probes on J20. And though they might not have fielded probes across there Y8/Y9 fleet that doesn’t mean they will or could install boom receivers into them. It’s not a drop in kit it requires changes to the structure of the fuselage. And although it might not be as easy to tank if it’s less expensive to fit.
It would be easier to sell Y20 tankers to nations with existing F16 and F15 fleets like Pakistan or the Middle East than to adopt the Boom for their own use.
If the aim of the PLAAF is to build up its tanker forces Probe and Drogue is the easiest way to get the most bang for the buck.

Just to comment on your conjecture again. No aircraft has both systems built in for reception. And changing systems doesn’t make sense. Having both systems would add excess weight complexity that in a fighter isn’t needed. It would also shut down the production line and force retooling that can take years and substantially increase costs.
The same for a bomber.
I agree you can turn a boom into a Drogue. But you can only tank one bird per Boom/Boom drogue. A Drogue pod system can have any number of receivers at once.
Yes refueling is quicker on boom. But again in this case not a single known boom receiver in the fleet well a number of Probe and Drogue types.
Yes only one prototype for the transport/Awacs class yet that doesn’t prove Booms that just means they are taking there time. Probe systems can be added as retrofits where Boom systems cannot.

TerraN_EmpirE said:

Just to comment on your conjecture again. No aircraft has both systems built in for reception. And changing systems doesn’t make sense. Having both systems would add excess weight complexity that in a fighter isn’t needed. It would also shut down the production line and force retooling that can take years and substantially increase costs.
The same for a bomber.
I agree you can turn a boom into a Drogue. But you can only tank one bird per Boom/Boom drogue. A Drogue pod system can have any number of receivers at once.
Yes refueling is quicker on boom. But again in this case not a single known boom receiver in the fleet well a number of Probe and Drogue types.
Yes only one prototype for the transport/Awacs class yet that doesn’t prove Booms that just means they are taking there time. Probe systems can be added as retrofits where Boom systems cannot.

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Australian KC-30A with two systems of refueling, and Ex-Singapore air force KC-135 too. Also French Air force KC-135.

lcloo said:

KC-30A with two systems of refueling, and Ex-Singapore air force KC-135 too.View attachment 61126View attachment 61127

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You missed the point, he is talking about the refueled aircraft, not the re-fueler. The only aircrafts that can both receive from Boom and probe are UK E-3D & French E-3F.

I heard another challenge with booms is that fighters can't accept the fuel as fast the boom pumps it. Is this true?

Twix101 said:

You missed the point, he is talking about the refueled aircraft, not the re-fueler. The only aircrafts that can both receive from Boom and probe are UK E-3D & French E-3F.

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My bad, I was focusing on Y20 tanker's configuration, instead of fuel receiving aircraft.

banjex said:

I heard another challenge with booms is that fighters can't accept the fuel as fast the boom pumps it. Is this true?

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Yes, fighter jets can only accept fuel at 1,000 to 3,000 lbs per minute. The full capacity of a flying boom is 6,000 lbs per minute, as compared to 1,500-2,000 lbs per minute for a hose-and-drogue. As a general rule of thumb, flying boom fits bigger planes like bombers, AEW planes, and transports, whereas hose-and-drogue suits fighter jets (and the only approach possible for helicopters).
As a heavy fighter with big internal tanks, J-20 is somewhere in between: assuming it can accept 3,000 lbs per minute from a boom, it is still about twice as fast as from a hose-and-drogue (which is also not easy to catch). Quicker refueling is critical for the survival of the stealthy fighter as well as the huge tanker during wartime.

xyqq said:

Yes, fighter jets can only accept fuel at 1,000 to 3,000 lbs per minute. The full capacity of a flying boom is 6,000 lbs per minute, as compared to 1,500-2,000 lbs per minute for a hose-and-drogue. As a general rule of thumb, flying boom fits bigger planes like bombers, AEW planes, and transports, whereas hose-and-drogue suits fighter jets (and the only approach possible for helicopters).
As a heavy fighter with big internal tanks, J-20 is somewhere in between: assuming it can accept 3,000 lbs per minute from a boom, it is still about twice as fast as from a hose-and-drogue (which is also not easy to catch). Quicker refueling is critical for the survival of the stealthy fighter as well as the huge tanker during wartime.

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Russian UPAZ-1 pods can reach in excess of 5000 lbs per minute with 52mm dia hoses (since they have to fill Tu-160s with these!), but the newest booms on the KC-30, KC-46 and KC-10 are able to transfer up to 8000 lbs per minute. Ultimately the boom is still better for large aircraft, however the USAF is not an example to emulate by using it for tactical fighters. Just by having the ability to refuel two smaller receivers in parallel the efficiency of probe/drogue rapidly outstrips the boom for handling smaller aircraft.

It's also misleading to suggest 5th generation fighters have higher fuel requirements - they just carry all of it internally so as to avoid the RCS penalty of drop tanks. If you factor external fuel into the load of a 4th generation aircraft, you end up with similar amounts, especially when you consider that 5th generation fighters tend to be larger, so it's no use comparing them to light 4th gens like the F-16 or J-10. Against a Flanker or F-15 with conformal tanks suddenly the J-20 doesn't look so special anymore in this regard.

Stealth has little bearing on the rift in fuel capacity between strategic bombers and tactical fighters, so the applicability of the boom hasn't changed.

Not sure which airbase this is...



Naval Y-9...

Interesting to see that no PLAAF transport aircraft are IFR-capable. Not sure whether these aircraft are fitted for but not with IFR probes or just not designed to have this capability.

Not that the PLAAF would need such capabilities to operate in the East Asia region, but they would need to consider IFR variants if they wish to expand their reach to other continents.