Re: New RAAF Air-To-Air Refuelling Capability

[Errol Cavit]

"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.

[matt weber]

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..

[Guy Alcala]

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

[matt weber]

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

[JB]

"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

[Guy Alcala]

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

[JB]

> 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]

"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

[BB]

"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.

[Guy Alcala]

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

[matt weber]

On Tue, 01 Jul 2003 08:40:51 GMT, Guy Alcala
> wrote:

>JB wrote:
>
>> True enough, it does burn more fuel, but possibly not enough to be an issue.
>> Actually, in domestic ops, the RR is the most thirsty of the engines.
>>
>> Some numbers:
>> 767-200 PW
>> Fuel to climb to FL330 (at 155,000 kgs start weight) 3280 kg
>> Cruise at FL330
>> @ 155k, 5086 kgs/hr
>> @ 130k, 4510 kgs/hr
>> @ 110k, 3994 kgs/hr
>>
>> 767-300 GE
>> Fuel to climb to FL330 (at 155,000 kgs start weight) 3010 kg
>> Cruise at FL330
>> @ 155k, 4940 kgs/hr
>> @ 130k, 4476 kgs/hr
>> @ 110k, 3982 kgs/hr
>>
>> The numbers are for a .79 cruise, and reduce by just on 400 kgs/hr (for
>> both) if you are holding.
>>
>> The 767-300 has a bit less drag than the -200, so I would expect a GE
>> equipped 200 to be slightly worse than these figures. You can't use a 300,
>> as there will be tail clearance issues with the boom refuelling gear.
>
>Do you happen to know why the -300s have less drag? Offhand I'd expect the
>opposite, given the larger wetted area.
larger wetted area, but the aircraft is transonic and the longer
fuselage increase the 'fineness' or ratio of cross section to length,
which tends to reduce drag in the transonic and supersonic regimes.
Relatively few notice just how Long (and thin) Concorde actually is.
It is about 2 meters shorter than an a330-300!

[BB]

"Dave Proctor" > wrote in message
...
> Whilst undoubtedly under the effects of alcohol, "BB" >
> wrote:
>
> > The 767-200 are showing signs of a fair bit of wear and tear.
>
> Only recently though, and mainly in the cabin. For the first part of
> their life they were used on international ops, thus they had a low
> number of cycles whilst having high passenger utilisation.
>
> lately though they have been used on the monorail, so their cycles
> have gone up, along with their passenger usage. Given their imminenet
> retirement, there has been no refurbishment.
>
> Whilst the cabins look tired, as far as cycles go most of them are in
> middle age - not young, but not close to retirement either.
>
> =========
>
> Dave
>
> Don't Drink Drive....
> It's A Laundry Detergent

Structurally as well... increasing amounts of corrosion and the like
being found... especially in cargo areas...

Regards,
BB.