New RAAF Air-To-Air Refuelling Capability

"Trevor Fenn" wrote in message
...
(The Enlightenment) wrote in


A330s will be in the Qantas inventory. The A330 has larger cargo
capaciy and is big enough not to require additional tankage.


Kinda hard to build a tanker without extra tankage.



I'm fairly sure that the current RAAF B-707s (_not_ KC-135s) didn't have any
tankage added.

--
Errol Cavit
to email, my middle initial is G | "I see; power without responsibility, the
prerogative of the harlot throughout the ages." Kipling replying to
Beaverbrook, who was boasting of his power.

On Mon, 30 Jun 2003 11:47:54 -0000, (Trevor
Fenn) wrote:

(The Enlightenment) wrote in


A330s will be in the Qantas inventory. The A330 has larger cargo
capaciy and is big enough not to require additional tankage.


Kinda hard to build a tanker without extra tankage.

Not hard at all actually.
On a 777-200ER, if you fill the tanks,
171,000 liters is about 301,000 pounds of fuel. EW is 320,000
pounds, and most operators have MGTOW's in the 620-630,000 pound
range. Add in the refueling gear, and well, you are probably going to
be constrained on the fuel load.

In otherwords, the standard tankage covers the entire spread between
EW and MGTOW in most configurations. The A330-200 and -300 are not
much different in that regard.

A330 has 130,000 liters fuel capacity, which is about 229,000 pounds.
EW on the A330 is 265-275,000 pounds, MGTOW is 513,000,
so with full tanks, it is 494,000-504,000 pounds. In other words
there is very little point in putting more tankgage in. The weight of
the tank will consume much of the available remaining lift capacity,
and even if the tank weigh nothing, 5000 liters is about the most
additional fuel you can hope to carry. That's not much of a tank.

My gut feel is the air to air refueling gear will eat up most of the
available weight left anyway. So additional tanks give only a very
small increase in capacity..

JB wrote:

They've been orphans in QF operations for a very long time. Whilst I'm sure
there is a cost, I doubt that it's enough to really be a problem. There is
already plenty of expertise in place with regard to maintenance of these
engines.

I suspect it depends on exactly how the deal is structured. Are they going PFI,
is it going to be fully RAAF, some hybrid? On the orphan issue, does Qantas
want to get rid of them because they're too small, because they _are_ orphans
and not cost-effective, or some other reason? The other issue might be how
widely available parts will be for the JT9 for 20 years or so; after all, the
last new JT9D was produced in 1990. The JT9D seems likely to disappear from
service long before the other engines.

There are no pilot training/currency issues. If that's all the RAAF have,
then they won't have a currency or training problem. In practice, I operate
all three types of engine, and there aren't any practical issues, other than
remembering (or not) a few different limits. Procedurally more or less
identical.

Good to know. What's the thrust on the JT9s, compared to the other engines?
Payload capability operating from Learmonth and Tindal is likely to be a factor.

Guy

On Mon, 30 Jun 2003 22:19:42 GMT, Guy Alcala
wrote:

JB wrote:

They've been orphans in QF operations for a very long time. Whilst I'm sure
there is a cost, I doubt that it's enough to really be a problem. There is
already plenty of expertise in place with regard to maintenance of these
engines.

I suspect it depends on exactly how the deal is structured. Are they going PFI,
is it going to be fully RAAF, some hybrid? On the orphan issue, does Qantas
want to get rid of them because they're too small, because they _are_ orphans
and not cost-effective, or some other reason? The other issue might be how
widely available parts will be for the JT9 for 20 years or so; after all, the
last new JT9D was produced in 1990. The JT9D seems likely to disappear from
service long before the other engines.

There are no pilot training/currency issues. If that's all the RAAF have,
then they won't have a currency or training problem. In practice, I operate
all three types of engine, and there aren't any practical issues, other than
remembering (or not) a few different limits. Procedurally more or less
identical.

Good to know. What's the thrust on the JT9s, compared to the other engines?
Payload capability operating from Learmonth and Tindal is likely to be a factor.

Guy
JT9D's covered a wide range, but I believe the 767-200's have 7R's,
which in this application are 50,000 pounds thrust each. Runway
requirement/lift capability is rarely much of an issue with the -200.

You can get several variants of the CF6-80 for the 767-200ER, as well
as PW4000's. For thrust pick a number from 50,000 to about 57,000
pounds.

No RR engine was ever certified for the -200

"Guy Alcala" wrote in message

Do you happen to know why the -300s have less drag? Offhand I'd expect
the
opposite, given the larger wetted area.

Better fineness ratio.


Thanks for the info. I suspect FL330 is probably a good 8,000 feet higher
than
F-111s are likely to be cruising, or loaded F-18s. Certainly, that's far
higher
than the typical refueling altitudes the US uses in combat (FL210-250
being
quite typical), and most trans-oceanic ferry flights by U.S. fighters also
seem
to be done at FL250, presumably to prevent the need for constant climbs
from and
descents to refueling altitude.

I know. I chose the figure as it was about as high as they would reasonably
go at max weight. None of the engines are at their best when kept down low
though. I was a little surprised at just how well the PW compared in that
circumstance.

JB

matt weber wrote:

On Mon, 30 Jun 2003 22:19:42 GMT, Guy Alcala
wrote:

JB wrote:

They've been orphans in QF operations for a very long time. Whilst I'm sure
there is a cost, I doubt that it's enough to really be a problem. There is
already plenty of expertise in place with regard to maintenance of these
engines.

I suspect it depends on exactly how the deal is structured. Are they going PFI,
is it going to be fully RAAF, some hybrid? On the orphan issue, does Qantas
want to get rid of them because they're too small, because they _are_ orphans
and not cost-effective, or some other reason? The other issue might be how
widely available parts will be for the JT9 for 20 years or so; after all, the
last new JT9D was produced in 1990. The JT9D seems likely to disappear from
service long before the other engines.

There are no pilot training/currency issues. If that's all the RAAF have,
then they won't have a currency or training problem. In practice, I operate
all three types of engine, and there aren't any practical issues, other than
remembering (or not) a few different limits. Procedurally more or less
identical.

Good to know. What's the thrust on the JT9s, compared to the other engines?
Payload capability operating from Learmonth and Tindal is likely to be a factor.

Guy
JT9D's covered a wide range, but I believe the 767-200's have 7R's,
which in this application are 50,000 pounds thrust each. Runway
requirement/lift capability is rarely much of an issue with the -200.

It appears that the Qantas 767-200ERs probably have a MTOW of 350,000 lb., judging by
a Boeing 767-200/200ER runway length takeoff chart* which shows a/c with the
JT9D-7R4D/7R4E or CF6-80A/A2 engines for that weight, and I agree that at that MTOW
takeoff distances should rarely be a problem, even in hot conditions.

*Found on the web some time back.

You can get several variants of the CF6-80 for the 767-200ER, as well
as PW4000's. For thrust pick a number from 50,000 to about 57,000
pounds.

Takeoff Runway length Charts for 200ERs with MTOWs of 380,000 (CF6-80C2-B2 or PW
4052) and 387,000 lb. (CF6-80C2-B4 or PW4056) on hot days (ISA +17C) show that runway
length is definitely becoming a factor. So, if they stick with lower gross weight
200ERs, no problem, but if they want to maximise payload and fuel offload in hot/high
conditions, the lower gross weight JT9D-powered a/c aren't going to cut it. While
the JT9D 767s shouldn't be anywhere near as limited in TOW as the USAF KC-135Es were
when based in the Gulf (or the really pitiful KC-135As), that still could be a
significant operational limitation. It will be interesting to see what the RAAF
decides to do (or rather, what the Government's willing to pay for), given that used
767 airframes seem to be relatively cheap and available these days. Guess it depends
what the market for freighter conversions is as well.

Guy

It appears that the Qantas 767-200ERs probably have a MTOW of 350,000 lb.,
judging by
a Boeing 767-200/200ER runway length takeoff chart* which shows a/c with
the
JT9D-7R4D/7R4E or CF6-80A/A2 engines for that weight, and I agree that at
that MTOW
takeoff distances should rarely be a problem, even in hot conditions.

Their max t/o weight at the moment is 146,000 kgs. It used to be 155,000,
but was reduced when no longer needed for long haul ops. Registration fees
are based on this weight, so their is no point having more than you need.

Takeoff Runway length Charts for 200ERs with MTOWs of 380,000 (CF6-80C2-B2
or PW
4052) and 387,000 lb. (CF6-80C2-B4 or PW4056) on hot days (ISA +17C) show
that runway
length is definitely becoming a factor. So, if they stick with lower
gross weight
200ERs, no problem, but if they want to maximise payload and fuel offload
in hot/high
conditions, the lower gross weight JT9D-powered a/c aren't going to cut
it. While
the JT9D 767s shouldn't be anywhere near as limited in TOW as the USAF
KC-135Es were
when based in the Gulf (or the really pitiful KC-135As), that still could
be a
significant operational limitation. It will be interesting to see what
the RAAF
decides to do (or rather, what the Government's willing to pay for), given
that used
767 airframes seem to be relatively cheap and available these days. Guess
it depends
what the market for freighter conversions is as well.

It all rather depends what you want to do with them. If you are buying
tankers, then with max fuel loads you will end up with t/o weights around
the 150 tonne mark. No performance problem at all. I you want to carry 30
tonnes of freight, and play tankers simultaneously, then you're looking at
the wrong aircraft. You will need something substantially bigger, and more
expensive.

As for 767s lying around the countryside...be interesting to see what
condition most of them are in. Remember, you can't look at 300s, as they'll
drag the refuelling boom on the ground when they lift off.

JB

"JB" wrote in message
...

are based on this weight, so their is no point having more than you need.

are based on this weight, so there is no point having more than you need.

Damn, hate it when I do that...

JB

"Errol Cavit" wrote in message
...
"Trevor Fenn" wrote in message
...
(The Enlightenment) wrote in


I'm fairly sure that the current RAAF B-707s (_not_ KC-135s) didn't have
any
tankage added.

--
Errol Cavit
to email, my middle initial is G | "I see; power without responsibility,
the
prerogative of the harlot throughout the ages." Kipling replying to
Beaverbrook, who was boasting of his power.



That's correct... the main difference between the RAAF 707 tanker and a
standard 707 is the addition of replenish valves and lines to allow the
centre wing tanks to be refilled from the main tanks.... but the tankage
itself is identical...

Regards,
BB.

JB wrote:

It appears that the Qantas 767-200ERs probably have a MTOW of 350,000 lb.,
judging by
a Boeing 767-200/200ER runway length takeoff chart* which shows a/c with
the
JT9D-7R4D/7R4E or CF6-80A/A2 engines for that weight, and I agree that at
that MTOW
takeoff distances should rarely be a problem, even in hot conditions.

Their max t/o weight at the moment is 146,000 kgs. It used to be 155,000,
but was reduced when no longer needed for long haul ops. Registration fees
are based on this weight, so their is no point having more than you need.

Thanks for the info. Even 155,000 kgs does seem rather lacking, although they
might be able to boost that during any freighter conversion.

Takeoff Runway length Charts for 200ERs with MTOWs of 380,000 (CF6-80C2-B2
or PW
4052) and 387,000 lb. (CF6-80C2-B4 or PW4056) on hot days (ISA +17C) show
that runway
length is definitely becoming a factor. So, if they stick with lower
gross weight
200ERs, no problem, but if they want to maximise payload and fuel offload
in hot/high
conditions, the lower gross weight JT9D-powered a/c aren't going to cut
it. While
the JT9D 767s shouldn't be anywhere near as limited in TOW as the USAF
KC-135Es were
when based in the Gulf (or the really pitiful KC-135As), that still could
be a
significant operational limitation. It will be interesting to see what
the RAAF
decides to do (or rather, what the Government's willing to pay for), given
that used
767 airframes seem to be relatively cheap and available these days. Guess
it depends
what the market for freighter conversions is as well.

It all rather depends what you want to do with them. If you are buying
tankers, then with max fuel loads you will end up with t/o weights around
the 150 tonne mark. No performance problem at all. I you want to carry 30
tonnes of freight, and play tankers simultaneously, then you're looking at
the wrong aircraft. You will need something substantially bigger, and more
expensive.

They certainly should have more ability to act as deployment tankers (also
carrying freight/personnel) than anything based on a 707, so the higher gross
weights may well matter. Depends how often you think you'll need to operate out
of area, and how much tanking help (from allies) you can expect for the transit.

As for 767s lying around the countryside...be interesting to see what
condition most of them are in. Remember, you can't look at 300s, as they'll
drag the refuelling boom on the ground when they lift off.

Has that actually been established, or is it more a question of 'yeah, you could
do it, but it will screw the takeoff and landing distances because you can't
rotate as much?' I wonder if the A330 has the same problem (a bigger
tanker/transport than the 767, but maybe too big/heavy for many of the bases the
RAAF might want to work from, in addition to the other issues).

Guy