Bolkcom of the CRS against F/A-22

In article ,
"Kevin Brooks" wrote:

"Henry J Cobb" wrote in message
...
Bolkcom said the Raptor's 540-nautical mile unrefueled combat radius
dictated it operated from forward bases -- another drawback for a
Pentagon facing potential conflict in distant lands with perhaps scant
bases nearby from which to operate.

Or it could be (gasp!) refueled;

Or, more to the point, it has a *lot* more than a 540 mile combat
radius, over 840 miles.

--
cirby at cfl.rr.com

Remember: Objects in rearview mirror may be hallucinations.
Slam on brakes accordingly.

On Fri, 05 Mar 2004 00:50:27 GMT, Chad Irby wrote:

In article ,
"Kevin Brooks" wrote:

"Henry J Cobb" wrote in message
...
Bolkcom said the Raptor's 540-nautical mile unrefueled combat radius
dictated it operated from forward bases -- another drawback for a
Pentagon facing potential conflict in distant lands with perhaps scant
bases nearby from which to operate.

Or it could be (gasp!) refueled;

Or, more to the point, it has a *lot* more than a 540 mile combat
radius, over 840 miles.

and the source of this 840 mile figure is???,

Does that figure include the 200nm supercruise profile?

Just want to know...

Cheers
John Cook

Any spelling mistakes/grammatic errors are there purely to annoy. All
opinions are mine, not TAFE's however much they beg me for them.

Email Address :-
Spam trap - please remove (trousers) to email me
Eurofighter Website :- http://www.eurofighter-typhoon.co.uk

In article ,
John Cook wrote:

On Fri, 05 Mar 2004 00:50:27 GMT, Chad Irby wrote:

Or, more to the point, it has a *lot* more than a 540 mile combat
radius, over 840 miles.

and the source of this 840 mile figure is???,

Several, including:

http://www.periscope.ucg.com/sampleWeapons.html

http://www.fighters.co.yu/Data/Usa/FA22ARaptor-data.htm

http://www.harcirepulo.hu/F-22/

--
cirby at cfl.rr.com

Remember: Objects in rearview mirror may be hallucinations.
Slam on brakes accordingly.

On Sat, 06 Mar 2004 02:09:45 GMT, Chad Irby wrote:

In article ,
John Cook wrote:

On Fri, 05 Mar 2004 00:50:27 GMT, Chad Irby wrote:

Or, more to the point, it has a *lot* more than a 540 mile combat
radius, over 840 miles.

and the source of this 840 mile figure is???,

Several, including:



OK first their not really what I would call 'good' sources, OK for
homework and newspaper reporters, not for much more though...

This is going to sound a little harsh... but do you have anything with
a little more authority or credability?

http://www.periscope.ucg.com/sampleWeapons.html
You might want them to check their fuel load ;-) its possible they
confused kg with litres... and thats where the error has crept in.

I would wager that the Raptors real fuel load is sub 20,000lbs my
educated guess is around 18,000-19,500lbs.
But you'll have to wait till its not classified to prove me right or
wrong, or someone 'in the know' gives us a hint.


http://www.fighters.co.yu/Data/Usa/FA22ARaptor-data.htm
This site is under construction, try to go to the UK link etc..
BTW the Eurofighter Data has errors (see if you can find it)... so
what makes you think that the F-22 is correct?


http://www.harcirepulo.hu/F-22/

This site has lots of inaccurate info on it, and it only took me 10
seconds to find out too.


I'm not convinced by these sites, If it was from Janes, Brasseys,
Lockheed, USAF, GAO, RAND, these I would be more interested in.


Cheers
John Cook

Any spelling mistakes/grammatic errors are there purely to annoy. All
opinions are mine, not TAFE's however much they beg me for them.

Email Address :-
Spam trap - please remove (trousers) to email me
Eurofighter Website :- http://www.eurofighter-typhoon.co.uk

In article ,
John Cook wrote:

OK first their not really what I would call 'good' sources, OK for
homework and newspaper reporters, not for much more though...

This is going to sound a little harsh... but do you have anything with
a little more authority or credability?

Not as such, but you should also remember that the *other* sources for
range (the short ones) haven't really got any better of a record. As of
right now, combat range for the F-22 is still in the "estimated" area,
but it's really interesting that the range for this new plane, with
newer engines and supercruise, is often represented as the same or less
than an F-15 (or even an F-4!) with the same fuel load...

--
cirby at cfl.rr.com

Remember: Objects in rearview mirror may be hallucinations.
Slam on brakes accordingly.

On Sat, 06 Mar 2004 14:16:43 +1100, John Cook
wrote:

On Sat, 06 Mar 2004 02:09:45 GMT, Chad Irby wrote:

In article ,
John Cook wrote:

On Fri, 05 Mar 2004 00:50:27 GMT, Chad Irby wrote:

Or, more to the point, it has a *lot* more than a 540 mile combat
radius, over 840 miles.

and the source of this 840 mile figure is???,

Several, including:



OK first their not really what I would call 'good' sources, OK for
homework and newspaper reporters, not for much more though...

This is going to sound a little harsh... but do you have anything with
a little more authority or credability?

http://www.periscope.ucg.com/sampleWeapons.html
You might want them to check their fuel load ;-) its possible they
confused kg with litres... and thats where the error has crept in.

I would wager that the Raptors real fuel load is sub 20,000lbs my
educated guess is around 18,000-19,500lbs.
But you'll have to wait till its not classified to prove me right or
wrong, or someone 'in the know' gives us a hint.

Last I heard it was a tad over 18,500.

Just thought I'd chuck this in again... I first wrote this in 1998...
and have left it unchanged - usual caveats apply...

*********************quote

"I will start with the ferry range as this is the easiest.

The EF2000 can fly 2000 Nm (Nautical Miles) using 5700 litres of fuel
+ 2 x 1000 litres drop tanks, total 7700ltrs , this gives a figure of
3.85 ltrs per nautical mile for an engine that produces 120kN dry
thrust.

This figure does not include any reserve fuel, but as all aircraft
usually have this margin, it can for this purpose be ignored.

But now we have established a fuel usage figure for ferry range for a
120kN class engine.

Now the F22 can carry 11000 litres of fuel internally, but the engines
produce 220kN of thrust, if we use the same ratio 220kN/120kN and
apply this to the fuel we get 7.05 litres per Nm.

Ok the above is rough, and no doubt somebody will tell me larger
engines are more/less efficent, and I would like to know!!!.

So the ferry range for the F22 is around 11000/7.05= 1560Nm using
internal fuel.
With additional drop tanks (9000 litres) this extends to 2837Nm.

Using this figure of 7.05 ltrs per Nm, the F22 can fly around 780Nm
combat radius, with no loiter time, using internal fuel only."

****************Unquote

So using ferry type configuration, cruising at its most fuel
efficient, and at its best cruise altitude the Raptors range is
780nm, add supercruise, weapons and combat flight profile. and it
only gets shorter.
I would hazard a guess that the Raptors A to A combat radius is
within the 540 to 620nm with about 25 mins loiter.

This does depend on Internal fuel load...

Hope this helps

Cheers





John Cook

Any spelling mistakes/grammatic errors are there purely to annoy. All
opinions are mine, not TAFE's however much they beg me for them.

Email Address :-
Spam trap - please remove (trousers) to email me
Eurofighter Website :- http://www.eurofighter-typhoon.co.uk

John Cook wrote in message . ..
"I will start with the ferry range as this is the easiest.

The EF2000 can fly 2000 Nm (Nautical Miles) using 5700 litres of fuel
+ 2 x 1000 litres drop tanks, total 7700ltrs , this gives a figure of
3.85 ltrs per nautical mile for an engine that produces 120kN dry
thrust.

This figure does not include any reserve fuel, but as all aircraft
usually have this margin, it can for this purpose be ignored.

But now we have established a fuel usage figure for ferry range for a
120kN class engine.

Sadly, this is not how one calculates range for aircraft. The "liters
per mile" is not constant, but rather a function of specific fuel
consumption (fuel consumption / thrust), lift/drag (dependent on
speed, altitude, and weight), speed, and weight fraction (wet weight /
empty weight).

According to aerospaceweb.org, the Eurofighter has a dry weight of
9750 kg and an internal fuel capacity of 4000 kg (weight fraction of
1.41) while the F-22 has a dry weight of 34000 lb and an internal fuel
capacity of 25000 pounds (weight fraction of 1.68). Range is
proportional to the logarithm of weight fraction, so assuming that
lift/drag are fairly similar and that the engines are of comparable
technology, the F-22 should be able to cruise 50% further on internal
fuel than the EF2000.

Using 2x1000L drop tanks raises the EF2000's weight fraction to 1.55,
so the F-22 should still be able to cruise 17% further disregarding
its lift/drag advantage (no external tanks).

-jake

On 6 Mar 2004 17:09:52 -0800, (Jake McGuire) wrote:

My attempt at rough range calculation snipped

Sadly, this is not how one calculates range for aircraft. The "liters
per mile" is not constant, but rather a function of specific fuel
consumption (fuel consumption / thrust), lift/drag (dependent on
speed, altitude, and weight), speed, and weight fraction (wet weight /
empty weight).

According to aerospaceweb.org, the Eurofighter has a dry weight of
9750 kg and an internal fuel capacity of 4000 kg (weight fraction of
1.41)

The numbers have changed a lot since then, the Empty weight of the
Typhoon is 11,000kg, quite a hike isn't it.
But then again the fuel load is now at 4996kg, as confirmed by a pilot
to me personally and from a cockpit picture showing the fuel load
as 4992kg.
So the weight fraction now is as follows
Using the updated figures 15996/11000=1.45

while the F-22 has a dry weight of 34000 lb and an internal fuel
capacity of 25000 pounds (weight fraction of 1.68).
Now some of these figures seem very suspect to me...

Usual T/O weight 60klbs???
Max T/O weight 62klbs??

If you look at the empty weight of 34klbs and add 25klbs
you get 59klbs, Hmmm, add 2500lbs for 6 Amraam 120C and two Aim 9X
your at 61.5K, now add Cannon shells??? Ooops you just bust the Max
T/O weight.... what you going to take off so the pilot can get in...?
The max T/O weight looks very wrong, and I bet the Empty weight has
crept up too,( I think this because the figures quoted predate the
mutterings about weight gain)....


OK using the your figures the Raptor is 59klbs/34klbs is 1.73

But using the more likely figures you get 53klbs/34klbs=1.55


Now the second set of figures seem much more likely to me.


Range is
proportional to the logarithm of weight fraction, so assuming that
lift/drag are fairly similar and that the engines are of comparable
technology, the F-22 should be able to cruise 50% further on internal
fuel than the EF2000.

Its a bit closer than that!


Using 2x1000L drop tanks raises the EF2000's weight fraction to 1.55,
so the F-22 should still be able to cruise 17% further disregarding
its lift/drag advantage (no external tanks).

The conformal fuel tanks that are slated for tranche 3 look better
value they have a capacity of approximately 1,500 litres each could
extend the range of the aircraft by 25%, with 'surprising little
aerodynamic effect'.

Cheers


-jake

John Cook

Any spelling mistakes/grammatic errors are there purely to annoy. All
opinions are mine, not TAFE's however much they beg me for them.

Email Address :-
Spam trap - please remove (trousers) to email me
Eurofighter Website :- http://www.eurofighter-typhoon.co.uk

In article ,
John Cook wrote:

On 6 Mar 2004 17:09:52 -0800, (Jake McGuire) wrote:

Range is proportional to the logarithm of weight fraction, so
assuming that lift/drag are fairly similar and that the engines are
of comparable technology, the F-22 should be able to cruise 50%
further on internal fuel than the EF2000.

Its a bit closer than that!

Aside from the weight fraction, the F-22 is a *much* cleaner airframe
when carrying weapons. The EF2000 has conformal missiles, but it still
has a lot of extra hardware hanging out there in the airstream with a
normal load, and when you add on wing tanks, it gets very important.

Using 2x1000L drop tanks raises the EF2000's weight fraction to 1.55,
so the F-22 should still be able to cruise 17% further disregarding
its lift/drag advantage (no external tanks).

The conformal fuel tanks that are slated for tranche 3 look better
value they have a capacity of approximately 1,500 litres each could
extend the range of the aircraft by 25%, with 'surprising little
aerodynamic effect'.

....and the expanded wing for the "bomber" version of the F-22 should
have a *major* addition in fuel-carrying capability, for even less
effect.

--
cirby at cfl.rr.com

Remember: Objects in rearview mirror may be hallucinations.
Slam on brakes accordingly.