Why no CAS turboprops?

[Charles Gray]

A question-- why haven't any CAS aircrarft been designed with
turboprops or the pusher varient (I foreget what you call it)? Given
their slow operating speed, it would seem to be a natural match up. Is
it a case the they are obsolete, or more of a case that people (read--
budget officials) have come to expect *jets*, on military aircraft.
Also, after a brief flurry of interest in USB (Upper surface
blowing) combat aircraft in the 1980's, nothing seems to have come of
it. The predicted STOL and payload advantages were rather
impressive-- did engineering problems come to the fore?

[Abe]

In article >,
says...
> A question-- why haven't any CAS aircrarft been designed with
> turboprops or the pusher varient (I foreget what you call it)?

The Argentinian Pucara is/was a CAS aircraft with turboprops.

http://fas.org/man/dod-101/sys/ac/row/pucara.htm

[Bob Liberty]

Have participated in CAS with an AC130.
ole nav

"Abe" > wrote in message
...
> In article >,
> says...
> > A question-- why haven't any CAS aircrarft been designed with
> > turboprops or the pusher varient (I foreget what you call it)?
>
> The Argentinian Pucara is/was a CAS aircraft with turboprops.
>
> http://fas.org/man/dod-101/sys/ac/row/pucara.htm
>
>

[Kevin Brooks]

"Abe" > wrote in message
...
> In article >,
> says...
> > A question-- why haven't any CAS aircrarft been designed with
> > turboprops or the pusher varient (I foreget what you call it)?
>
> The Argentinian Pucara is/was a CAS aircraft with turboprops.

As is the dual-role Super Tucano from Embraer; there is even a single seat
model (ALX).
http://www.embraer.com/english/

Brooks

>
> http://fas.org/man/dod-101/sys/ac/row/pucara.htm
>

[[email protected]]

Don't the brazilians(?) use the (Super) Tucano over the Amazon Basin

I Found the following link, which has quite a bit of info...

http://www.airforce-technology.com/projects/super_tucano/

[Yama]

"Charles Gray" > wrote in message
...
> A question-- why haven't any CAS aircrarft been designed with
> turboprops or the pusher varient (I foreget what you call it)? Given
> their slow operating speed, it would seem to be a natural match up. Is
> it a case the they are obsolete, or more of a case that people (read--
> budget officials) have come to expect *jets*, on military aircraft.

As others noted, many turboprops have and are being used in CAS duties
generally in Third World countries, where probable opposition is unlikely to
shoot back with too much stuff. Since there are plenty of suitable planes
(advanced trainers, for example) which can perform in the role, it's usually
waste to design purpose-built aircraft.

Major countries, who expect to meet first-rate opposition, don't build prop
CAS planes because it's a really bad idea. Some view even A-10 as too slow
and vulnerable against modern (truly deadly) low-altitude defences. There
have been some projects in the past (Piper Enforcer, a turboprop P-51(!)
comes to mind) but they haven't led to anything. If you want to fly low and
slow, get a helicopter.

[Les Matheson]

And in the MC-130E. BLU-82 forever. Now the MOAB, with more bang for your
buck.
--
Les
F-4C(WW),D,E,G(WW)/AC-130A/MC-130E EWO (ret)


"Bob Liberty" > wrote in message
. com...
> Have participated in CAS with an AC130.
> ole nav
>
> "Abe" > wrote in message
> ...
> > In article >,
> > says...
> > > A question-- why haven't any CAS aircrarft been designed with
> > > turboprops or the pusher varient (I foreget what you call it)?
> >
> > The Argentinian Pucara is/was a CAS aircraft with turboprops.
> >
> > http://fas.org/man/dod-101/sys/ac/row/pucara.htm
> >
> >
>
>

[R Haskin]

The Air Force (or any other country with a few million burning a hole in
their pocket) coulda had the Piper Enforcer...


"Charles Gray" > wrote in message
...
> A question-- why haven't any CAS aircrarft been designed with
> turboprops or the pusher varient (I foreget what you call it)? Given
> their slow operating speed, it would seem to be a natural match up. Is
> it a case the they are obsolete, or more of a case that people (read--
> budget officials) have come to expect *jets*, on military aircraft.
> Also, after a brief flurry of interest in USB (Upper surface
> blowing) combat aircraft in the 1980's, nothing seems to have come of
> it. The predicted STOL and payload advantages were rather
> impressive-- did engineering problems come to the fore?
>

[Kevin Brooks]

"Les Matheson" > wrote in message
news:JdmKb.52565$Fg.49542@lakeread01...
> And in the MC-130E. BLU-82 forever. Now the MOAB, with more bang for
your
> buck.

Not sure I'd call either one exactly a "CAS" (emphasis on the "close" part)
asset--God only knows what the danger close margin is for either of those
puppies.

Brooks

> --
> Les
> F-4C(WW),D,E,G(WW)/AC-130A/MC-130E EWO (ret)
>
>
> "Bob Liberty" > wrote in message
> . com...
> > Have participated in CAS with an AC130.
> > ole nav
> >
> > "Abe" > wrote in message
> > ...
> > > In article >,

> > > says...
> > > > A question-- why haven't any CAS aircrarft been designed with
> > > > turboprops or the pusher varient (I foreget what you call it)?
> > >
> > > The Argentinian Pucara is/was a CAS aircraft with turboprops.
> > >
> > > http://fas.org/man/dod-101/sys/ac/row/pucara.htm
> > >
> > >
> >
> >
>
>

[Charles Gray]

I'm sorry-- let me be a little more specific.
Is there any reason why a turboprop or pusher turboprop would be
less suitable for the low and slow CAS mission than say an aircraft
with a-10 style jet engines? I.E., is there some technological hurdle
that makes them innately less effective than jets at the speeds and
altitudes that CAS operates at?

[Abe]

In article >,
says...
> I'm sorry-- let me be a little more specific.
> Is there any reason why a turboprop or pusher turboprop would be
> less suitable for the low and slow CAS mission than say an aircraft
> with a-10 style jet engines? I.E., is there some technological hurdle
> that makes them innately less effective than jets at the speeds and
> altitudes that CAS operates at?

The point is that "low and slow" isn't a healthy thing to do. "Low and
fast" is much preferable, even if it makes it harder to hit the target.

[Charles Gray]

On Tue, 6 Jan 2004 12:32:31 -0000, Abe > wrote:

>In article >,
>says...
>> I'm sorry-- let me be a little more specific.
>> Is there any reason why a turboprop or pusher turboprop would be
>> less suitable for the low and slow CAS mission than say an aircraft
>> with a-10 style jet engines? I.E., is there some technological hurdle
>> that makes them innately less effective than jets at the speeds and
>> altitudes that CAS operates at?
>
>The point is that "low and slow" isn't a healthy thing to do. "Low and
>fast" is much preferable, even if it makes it harder to hit the target.
I'm not entirely certain about that-- the A-10, although it took
damage in Desert Storm, certainly didn't seem like a suicidal
proposition. I knkow some pilots who claim that the A-10 was more of
a case that it wasn't "Sexy" enough rather than it didn't work.

[Abe]

In article >,
says...
> On Tue, 6 Jan 2004 12:32:31 -0000, Abe > wrote:
>
> >In article >,
> >says...
> >> I'm sorry-- let me be a little more specific.
> >> Is there any reason why a turboprop or pusher turboprop would be
> >> less suitable for the low and slow CAS mission than say an aircraft
> >> with a-10 style jet engines? I.E., is there some technological hurdle
> >> that makes them innately less effective than jets at the speeds and
> >> altitudes that CAS operates at?
> >
> >The point is that "low and slow" isn't a healthy thing to do. "Low and
> >fast" is much preferable, even if it makes it harder to hit the target.
> I'm not entirely certain about that-- the A-10, although it took
> damage in Desert Storm, certainly didn't seem like a suicidal
> proposition. I knkow some pilots who claim that the A-10 was more of
> a case that it wasn't "Sexy" enough rather than it didn't work.

On a modern battlefield, I wouldn't give the A-10 much of a life span.
It might armoured like a tank, but it's sitting duck.

How would the A-10 survive in a theatre full of modern vehicle-mounted
SAMs, I wonder?

[Charles Gray]

On Tue, 6 Jan 2004 22:21:45 -0000, Abe > wrote:

>In article >,
>says...
>> On Tue, 6 Jan 2004 12:32:31 -0000, Abe > wrote:
>>
>> >In article >,
>> >says...
>> >> I'm sorry-- let me be a little more specific.
>> >> Is there any reason why a turboprop or pusher turboprop would be
>> >> less suitable for the low and slow CAS mission than say an aircraft
>> >> with a-10 style jet engines? I.E., is there some technological hurdle
>> >> that makes them innately less effective than jets at the speeds and
>> >> altitudes that CAS operates at?
>> >
>> >The point is that "low and slow" isn't a healthy thing to do. "Low and
>> >fast" is much preferable, even if it makes it harder to hit the target.
>> I'm not entirely certain about that-- the A-10, although it took
>> damage in Desert Storm, certainly didn't seem like a suicidal
>> proposition. I knkow some pilots who claim that the A-10 was more of
>> a case that it wasn't "Sexy" enough rather than it didn't work.
>
>On a modern battlefield, I wouldn't give the A-10 much of a life span.
>It might armoured like a tank, but it's sitting duck.
>
>How would the A-10 survive in a theatre full of modern vehicle-mounted
>SAMs, I wonder?

Not well-- if you sent it in alone. However, with SEAD it would do
pretty well-- A-10's in the first gulf war took plenty of fire from
shoulder fired SAMs' as well as cannon fire and came back in a
landable condition-- imagine an F-22 or F-35 doing the same. Also,
unlike the faster, more "sexy" aircraft, slow CAS can loiter in the
area, prepared to shoot up the odd target.
It should also be noted that During Desert Storm, A-10's did very
well:
"The Air Force sent 144 A-10s to the theater. While flying only 30
percent of the Air Force's total sorties, these aircraft achieved more
than half of the confirmed Iraqi equipment losses and fired 90 percent
of the precision-guided Maverick missiles launched during Desert
Storm. They demonstrated versatility as daytime Scud hunters in Iraq
and even recorded two helicopter kills with their 30mm guns. Although
A-10s flew more than 8,000 sorties in Desert Storm, only five were
lost in combat in a very high-threat environment. "

[Abe]

In article >,
says...
>
> Not well-- if you sent it in alone. However, with SEAD it would do
> pretty well-- A-10's in the first gulf war took plenty of fire from
> shoulder fired SAMs' as well as cannon fire and came back in a
> landable condition-- imagine an F-22 or F-35 doing the same. Also,
> unlike the faster, more "sexy" aircraft, slow CAS can loiter in the
> area, prepared to shoot up the odd target.
> It should also be noted that During Desert Storm, A-10's did very
> well:
> "The Air Force sent 144 A-10s to the theater. While flying only 30
> percent of the Air Force's total sorties, these aircraft achieved more
> than half of the confirmed Iraqi equipment losses and fired 90 percent
> of the precision-guided Maverick missiles launched during Desert
> Storm. They demonstrated versatility as daytime Scud hunters in Iraq
> and even recorded two helicopter kills with their 30mm guns. Although
> A-10s flew more than 8,000 sorties in Desert Storm, only five were
> lost in combat in a very high-threat environment. "

However, how many aircraft were deployed in the CAS role in large
numbers during that conflict? Without anything to compare those numbers
to, they're meaningless. Who's to say that a similar, faster aircraft
would not have had even fewer losses?

[Gene Storey]

Would a helicopter count as a turboprop? Turbo-blade? :-)

[Abe]

In article <dGKKb.8616$6l1.5192@okepread03>, says...
> Would a helicopter count as a turboprop? Turbo-blade? :-)

Helo engines are usually referred to as "turboshaft", which aside from
sounding suspiciously like a porn film, is possibly just another name
for a turboprop.

I wonder what the V-22 engines are. Turboprop when facing forward,
turboshaft when facing upward? :)

[Kevin Brooks]

"Abe" > wrote in message
...
> In article <dGKKb.8616$6l1.5192@okepread03>, says...
> > Would a helicopter count as a turboprop? Turbo-blade? :-)
>
> Helo engines are usually referred to as "turboshaft", which aside from
> sounding suspiciously like a porn film, is possibly just another name
> for a turboprop.
>
> I wonder what the V-22 engines are. Turboprop when facing forward,
> turboshaft when facing upward? :)

Isn't the presence of a transmission in the latter what helps delineate it
from the former?

Brooks

[Kirk Stant]

The OV-10 (twin turboprops) was used quite a lot for CAS (by the Navy
mainly, see "Black Ponies") during Vietnam. And since then by the
Philippines, and probably Venuzuela (sp?).

It was designed for Counter Insurgency (COIN) operations, which was
usually defined as low threat ops including CAS (but that was before
the SA-7 appeared!).

Great plane in a relatively low threat environment. Sucks when there
is radar guided AAA or manpads around - as Marines found out during
DS. Just too slow to get away from the threat!

Fun plane to fly, though, and a great FAC platform.

Kirk

[Kevin Brooks]

"Kirk Stant" > wrote in message
om...
> The OV-10 (twin turboprops) was used quite a lot for CAS (by the Navy
> mainly, see "Black Ponies") during Vietnam. And since then by the
> Philippines, and probably Venuzuela (sp?).
>
> It was designed for Counter Insurgency (COIN) operations, which was
> usually defined as low threat ops including CAS (but that was before
> the SA-7 appeared!).
>
> Great plane in a relatively low threat environment. Sucks when there
> is radar guided AAA or manpads around - as Marines found out during
> DS. Just too slow to get away from the threat!
>
> Fun plane to fly, though, and a great FAC platform.

I can remember my brother telling me that the USAF kept OV-10's rotating
overhead during the hours he and his crew were down near the Laotian border
after their dustoff UH-1 had been shot down. He had a particular affection
for it after that.

Brooks

>
> Kirk

[WaltBJ]

I presume one reason high-bypass turbofans (A10) are preferred vice
turboprops is that in the balance the fans are a more economical
choice. No props to get nicked, no gearbox to worry about, over-all
less maintenance and less cost. And quieter - the Beech 1900s flying
overhead here really howl when trying to make an ETA. Less noise is
good when prowling around. But what is really good is a supersonic
approach when dealing with a known show target- surprise!
Walt BJ

[Abe]

In article >,
says...
>
> "Abe" > wrote in message
> ...
> > In article <dGKKb.8616$6l1.5192@okepread03>, says...
> > > Would a helicopter count as a turboprop? Turbo-blade? :-)
> >
> > Helo engines are usually referred to as "turboshaft", which aside from
> > sounding suspiciously like a porn film, is possibly just another name
> > for a turboprop.
> >
> > I wonder what the V-22 engines are. Turboprop when facing forward,
> > turboshaft when facing upward? :)
>
> Isn't the presence of a transmission in the latter what helps delineate it
> from the former?

Turboprops have transmissions also, I'm sure. At least, you'd need to
put some gearing between engine and props.

[Rick]

Abe wrote:

> Helo engines are usually referred to as "turboshaft", which aside from
> sounding suspiciously like a porn film, is possibly just another name
> for a turboprop.

A turboprop engine is configured so the output shaft will
mount a propeller. It has thrust bearings and is geared to
drive a propeller directly.

A turboshaft delivers its output to a shaft which may be
connected to nearly anything except directly to a propeller.

Rick

[Yama]

"Charles Gray" > wrote in message
...
> On Tue, 6 Jan 2004 22:21:45 -0000, Abe > wrote:
> >On a modern battlefield, I wouldn't give the A-10 much of a life span.
> >It might armoured like a tank, but it's sitting duck.
> >
> >How would the A-10 survive in a theatre full of modern vehicle-mounted
> >SAMs, I wonder?
>
> Not well-- if you sent it in alone. However, with SEAD it would do
> pretty well-- A-10's in the first gulf war took plenty of fire from
> shoulder fired SAMs' as well as cannon fire and came back in a
> landable condition-- imagine an F-22 or F-35 doing the same. Also,
> unlike the faster, more "sexy" aircraft, slow CAS can loiter in the
> area, prepared to shoot up the odd target.

But doesn't it sort of defeat the very idea of "survivable combat aircraft"
when you need a SEAD package et al to keep it alive?

Sure, passive protection will increase your survival chances in case of hit
but does it really help if you're so slow that you get hit much more often?

> It should also be noted that During Desert Storm, A-10's did very
> well:

Actually, A-10 operations to some well-defended areas were restricted after
some were shot down. Against something like Crotale or SA-15, I'd rate
A-10's survival odds as very low. Or gun systems like Marksman,
Tunguska...those have _very high_ hit probabilities. A turboprop CAS plane
would be even more vulnerable.

Of course, if you're content about bombing some hapless natives, then maybe
you don't have to worry about such threats and slow attack planes are
viable.

[Kevin Brooks]

"Abe" > wrote in message
...
> In article >,
> says...
> >
> > "Abe" > wrote in message
> > ...
> > > In article <dGKKb.8616$6l1.5192@okepread03>, says...
> > > > Would a helicopter count as a turboprop? Turbo-blade? :-)
> > >
> > > Helo engines are usually referred to as "turboshaft", which aside from
> > > sounding suspiciously like a porn film, is possibly just another name
> > > for a turboprop.
> > >
> > > I wonder what the V-22 engines are. Turboprop when facing forward,
> > > turboshaft when facing upward? :)
> >
> > Isn't the presence of a transmission in the latter what helps delineate
it
> > from the former?
>
> Turboprops have transmissions also, I'm sure. At least, you'd need to
> put some gearing between engine and props.

Some gearing yes; but I don't think they have anything as complex as the
transmissions employed on helos. Just a guess, though.

Brooks

[Abe]

In article .net>,
says...
> Abe wrote:
>
> > Helo engines are usually referred to as "turboshaft", which aside from
> > sounding suspiciously like a porn film, is possibly just another name
> > for a turboprop.
>
> A turboprop engine is configured so the output shaft will
> mount a propeller. It has thrust bearings and is geared to
> drive a propeller directly.
>
> A turboshaft delivers its output to a shaft which may be
> connected to nearly anything except directly to a propeller.

I'm a bit hazy on the difference here. Are you saying a turboprop has
no reduction gearing between engine and propellor?

If it does have gearing, then I'm not sure of the clear-cut difference
between that and a more complex transmission. Could you elaborate?

[Rick]

Abe wrote:

> I'm a bit hazy on the difference here. Are you saying a turboprop has
> no reduction gearing between engine and propellor?

No, a turboprop engine has reduction gearing between the
power turbine and the propeller shaft. The output shaft on a
turboprop engine is the propeller shaft, it is reduced in
speed to that required by the propeller and incorporates a
thrust bearing to transfer thrust to the engine mounts.

> If it does have gearing, then I'm not sure of the clear-cut difference
> between that and a more complex transmission. Could you elaborate?

If by "more complex transmission" you mean that of a
turboshaft then you are still a bit confused. The
"transmission" or reduction gear can and often is very
simple and less complicated than that of a turboprop engine.

Some turboshaft engines do not even have a reduction gear or
transmission, the power turbine is designed to turn at the
required speed for the application.

Look at it as a turboprop is only made to turn a propeller.
A turboshaft can turn everything else

Rick

[[email protected]]

"Kevin Brooks" > wrote:

>
>"Abe" > wrote in message
...
>> In article >,
>> says...
>> >
>> > "Abe" > wrote in message
>> > ...
>> > > In article <dGKKb.8616$6l1.5192@okepread03>, says...
>> > > > Would a helicopter count as a turboprop? Turbo-blade? :-)
>> > >
>> > > Helo engines are usually referred to as "turboshaft", which aside from
>> > > sounding suspiciously like a porn film, is possibly just another name
>> > > for a turboprop.
>> > >
>> > > I wonder what the V-22 engines are. Turboprop when facing forward,
>> > > turboshaft when facing upward? :)
>> >
>> > Isn't the presence of a transmission in the latter what helps delineate
>it
>> > from the former?
>>
>> Turboprops have transmissions also, I'm sure. At least, you'd need to
>> put some gearing between engine and props.
>
>Some gearing yes; but I don't think they have anything as complex as the
>transmissions employed on helos. Just a guess, though.
>
>Brooks
>
Yes, that's roughly correct AFIK. I know turboprops but not
Helicopters and I'd think that helicopters would require much
more complicated transmissions. Turboprops aren't very
complicated, just quite rugged, about 10 to 1 or so reduction
planetary gear-train with a 'torsion bar' type of driveshaft to
measure torque and some method of preventing the prop from
driving the engine (
--

-Gord.

[[email protected]]

Rick > wrote:

>Abe wrote:
>
>> Helo engines are usually referred to as "turboshaft", which aside from
>> sounding suspiciously like a porn film, is possibly just another name
>> for a turboprop.
>
>A turboprop engine is configured so the output shaft will
>mount a propeller. It has thrust bearings and is geared to
>drive a propeller directly.
>
>A turboshaft delivers its output to a shaft which may be
>connected to nearly anything except directly to a propeller.
>
>Rick

What aircraft would use that setup Rick? I can't imagine how you
could drive a prop directly from a turbine engine with no
reduction gearing? (or did I misread you?)
--

-Gord.

[Kevin Brooks]

"Gord Beaman" > wrote in message
...
> "Kevin Brooks" > wrote:
>
> >
> >"Abe" > wrote in message
> ...
> >> In article >,
> >> says...
> >> >
> >> > "Abe" > wrote in message
> >> > ...
> >> > > In article <dGKKb.8616$6l1.5192@okepread03>, says...
> >> > > > Would a helicopter count as a turboprop? Turbo-blade? :-)
> >> > >
> >> > > Helo engines are usually referred to as "turboshaft", which aside
from
> >> > > sounding suspiciously like a porn film, is possibly just another
name
> >> > > for a turboprop.
> >> > >
> >> > > I wonder what the V-22 engines are. Turboprop when facing forward,
> >> > > turboshaft when facing upward? :)
> >> >
> >> > Isn't the presence of a transmission in the latter what helps
delineate
> >it
> >> > from the former?
> >>
> >> Turboprops have transmissions also, I'm sure. At least, you'd need to
> >> put some gearing between engine and props.
> >
> >Some gearing yes; but I don't think they have anything as complex as the
> >transmissions employed on helos. Just a guess, though.
> >
> >Brooks
> >
> Yes, that's roughly correct AFIK. I know turboprops but not
> Helicopters and I'd think that helicopters would require much
> more complicated transmissions. Turboprops aren't very
> complicated, just quite rugged, about 10 to 1 or so reduction
> planetary gear-train with a 'torsion bar' type of driveshaft to
> measure torque and some method of preventing the prop from
> driving the engine (

Thanks. I don't know squat about turboprops, but I do know that helo
transmissions are typically pretty complex and are a rather common source of
maintenance trouble, not to mention being one of the more vulnerable spots
in terms of combat damage.

Brooks

> --
>
> -Gord.

[Rick]

wrote:

> What aircraft would use that setup Rick? I can't imagine how you
> could drive a prop directly from a turbine engine with no
> reduction gearing? (or did I misread you?)

I think you misread. A turboshaft engine can be used for
anything but driving a propeller directly. They are used to
power everything from generators and air compressors to
ships and water pumps. Some of them, like the GE LM2500
drive the output shaft directly from the power turbine at
3600 rpm so they can be direct coupled to a generator. They
do not use a gearbox.

Rick

[[email protected]]

Rick > wrote:

wrote:
>
>> What aircraft would use that setup Rick? I can't imagine how you
>> could drive a prop directly from a turbine engine with no
>> reduction gearing? (or did I misread you?)
>
>I think you misread. A turboshaft engine can be used for
>anything but driving a propeller directly. They are used to
>power everything from generators and air compressors to
>ships and water pumps. Some of them, like the GE LM2500
>drive the output shaft directly from the power turbine at
>3600 rpm so they can be direct coupled to a generator. They
>do not use a gearbox.
>
>Rick

Ok, that makes sense as far as it goes...I'm a little surprised
at the low speed of that turbine though but then, I'm used to
aircraft turbines that rotate much faster, could be something to
do with weight requirements though. The other part of your post
seems to say that you 'can' drive a prop directly and that's what
I was querying actually. Most aircraft turbines driving props
rotate at 13,000 - 14,000 RPM and that's much too fast for props
so you need reduction gearing.
--

-Gord.

[Rick]

wrote:


> Ok, that makes sense as far as it goes...I'm a little surprised
> at the low speed of that turbine though but then, I'm used to
> aircraft turbines that rotate much faster,

The LM2500 is an aeroderivative engine, that is it was born
to fly as the TF39 that powers the C5 transports. It was
adapted to stationary and marine use.

The power turbine sits behind the turbine that drives the
compressor. Just like the fan was driven in the aircraft
version the gases leaving the turbine drive the power
turbine at a much lower speed.

Take a google at a turbofan engine and you will see what I
mean.


> Most aircraft turbines driving props
> rotate at 13,000 - 14,000 RPM and that's much too fast for props
> so you need reduction gearing.

You are a bit slow, the smaller engines turn around 40,000 rpm.

Rick

[Hog Driver]

> On a modern battlefield, I wouldn't give the A-10 much of a life span.
> It might armoured like a tank, but it's sitting duck.
>
> How would the A-10 survive in a theatre full of modern vehicle-mounted
> SAMs, I wonder?

Thank goodness you don't fly them then. You wouldn't be able to employ your
weapons system effectively with an attitude like that.

A-10s don't work alone. HARM shooters abound, and even enough A-10s can
overwhelm a SAM site to cause mayhem and allow one to sneak through and
schwack it.

ATTACK!

[Hog Driver]

> However, how many aircraft were deployed in the CAS role in large
> numbers during that conflict? Without anything to compare those numbers
> to, they're meaningless. Who's to say that a similar, faster aircraft
> would not have had even fewer losses?

You take a look at the results of the failed A-16 experiment, son?

When you're talking CAS, you can't beat a Hawg.

ATTACK!

[Hog Driver]

> But doesn't it sort of defeat the very idea of "survivable combat
aircraft"
> when you need a SEAD package et al to keep it alive?

No. Idiots who think that one airplane can do every job might believe that
to be so, but when it comes to CAS, the A-10 is combat proven (against more
threats than you might think).

> Sure, passive protection will increase your survival chances in case of
hit
> but does it really help if you're so slow that you get hit much more
often?

A-10s normally will operate in conditions where F-16s or F-15Es wouldn't
dare to. It's the nature of true CAS operations that you stick your neck
out for the guy on the ground, and take hits to support him. When you have
that type of mindset going into the game, it's nice to have an aircraft that
can take hits and make it home. Speed isn't always better when it comes to
CAS.

> > It should also be noted that During Desert Storm, A-10's did very
> > well:
>
> Actually, A-10 operations to some well-defended areas were restricted
after
> some were shot down. Against something like Crotale or SA-15, I'd rate
> A-10's survival odds as very low. Or gun systems like Marksman,
> Tunguska...those have _very high_ hit probabilities. A turboprop CAS plane
> would be even more vulnerable.

Again, the A-10 doesn't operate solely in such environments (SA-15, etc.),
for good reason.

The SA-19/Tunguska and Marksman can be overflown even by the A-10, and with
Precision Engagement coming online with A-10 squadrons (some Guard units
already possess the capability) it will turn into a LGB plink-fest.

> Of course, if you're content about bombing some hapless natives, then
maybe
> you don't have to worry about such threats and slow attack planes are
> viable.

As long as they're hapless natives waving AK-47s in the air vs. helpless
natives, bomb 'em and strafe 'em 'till they are no more.

ATTACK!

[Abe]

In article >,
says...
> > However, how many aircraft were deployed in the CAS role in large
> > numbers during that conflict? Without anything to compare those numbers
> > to, they're meaningless. Who's to say that a similar, faster aircraft
> > would not have had even fewer losses?
>
> You take a look at the results of the failed A-16 experiment, son?

No I didn't, "dad".

> When you're talking CAS, you can't beat a Hawg.

I'm not saying the A-10 is a bad aircraft, I'm saying that a faster, but
otherwise similar aircraft, would be better, which was the thrust (if
you'll pardon the expression) of the original question.

[Lyle]

On Thu, 8 Jan 2004 22:18:06 -0500, "Hog Driver"
> wrote:

>> On a modern battlefield, I wouldn't give the A-10 much of a life span.
>> It might armoured like a tank, but it's sitting duck.
>>
>> How would the A-10 survive in a theatre full of modern vehicle-mounted
>> SAMs, I wonder?
>
>Thank goodness you don't fly them then. You wouldn't be able to employ your
>weapons system effectively with an attitude like that.
>
>A-10s don't work alone. HARM shooters abound, and even enough A-10s can
>overwhelm a SAM site to cause mayhem and allow one to sneak through and
>schwack it.
>
>ATTACK!
>
want there a mission in the 1st Gulf War, where A-10's Teamed up
F-4G's to take out some sam sites. the A-10'w would be the hunter, and
when the radars were turned on to engage them, they inturn were
engaged by the harms. and those that didnt turn their radar on were
then destroyed by the A-10's.

But seriously folks. all these people that say that the A-10 wont
survive in a modern battlefield are not looking at the big picture.

1. An A-10 is designed to operate within the vicinity of or next to
friendly groundforces.

2, if a A-10 can not survive in those conditions then that means that
we do not have air suppieriority(excuse spelling) and that enemy
aircraft are bombing friendly troops.

3. A-10 is going to be shot down, but so would a F-16/F-15 etc. and
it comes to the bottom line. how many tanks etc dose a plane have to
destroy to pay for itself. just look at how many helicopters that were
destroyed sofar in GW2. are we going to get rid of them cause they are
low and slow?


just my opionion.

[Yama]

"Hog Driver" > wrote in message
...
> > But doesn't it sort of defeat the very idea of "survivable combat
> aircraft"
> > when you need a SEAD package et al to keep it alive?
>
> No. Idiots who think that one airplane can do every job might believe
that
> to be so, but when it comes to CAS, the A-10 is combat proven (against
more
> threats than you might think).

Well, F-16 is also "combat proven" in CAS, then...

> > Sure, passive protection will increase your survival chances in case of
> hit
> > but does it really help if you're so slow that you get hit much more
> often?
>
> A-10s normally will operate in conditions where F-16s or F-15Es wouldn't
> dare to. It's the nature of true CAS operations that you stick your neck
> out for the guy on the ground, and take hits to support him. When you
have
> that type of mindset going into the game, it's nice to have an aircraft
that
> can take hits and make it home. Speed isn't always better when it comes
to
> CAS.

Having an option of speed is always better than not having it. Sure, flying
too fast over the target won't do any good in CAS, but having speed reserve
increases your chances against missiles etc, plus it makes your plane more
viable to other roles. Hence, highly specialized turboprop plane is a poor
idea in modern battlefield.

> > Actually, A-10 operations to some well-defended areas were restricted
> after
> > some were shot down. Against something like Crotale or SA-15, I'd rate
> > A-10's survival odds as very low. Or gun systems like Marksman,
> > Tunguska...those have _very high_ hit probabilities. A turboprop CAS
plane
> > would be even more vulnerable.
>
> Again, the A-10 doesn't operate solely in such environments (SA-15, etc.),
> for good reason.

And that good reason is that they're too vulnerable, despite all their
passive protection.

> The SA-19/Tunguska and Marksman can be overflown even by the A-10, and
with
> Precision Engagement coming online with A-10 squadrons (some Guard units
> already possess the capability) it will turn into a LGB plink-fest.

Then, you are flying too high to perform effective CAS, plus your odds of
actually detecting those things you are supposed to bomb are very poor. See:
Allied Force.

[Peter Stickney]

In article .net>,
Rick > writes:
> wrote:
>
>
>> Ok, that makes sense as far as it goes...I'm a little surprised
>> at the low speed of that turbine though but then, I'm used to
>> aircraft turbines that rotate much faster,
>
> The LM2500 is an aeroderivative engine, that is it was born
> to fly as the TF39 that powers the C5 transports. It was
> adapted to stationary and marine use.
>
> The power turbine sits behind the turbine that drives the
> compressor. Just like the fan was driven in the aircraft
> version the gases leaving the turbine drive the power
> turbine at a much lower speed.

O.K. That's a Free-Turbine Turboshaft. The output shaft is driven by
its own separate turbine, and, therefore, can be sized to turn at
whaver combination of torque & RPM you want, within certain limits.
The Gas Generator (Compressor/turbinw spools, and the burners) are
then able to turn at whatever speed is best for them. I'll bet it's
quite a bit faster.
Many turboprops are set up the same way - the output shaft is run off
its own turbine, and is separate from the Gas Generator. You can see
this on some commuter airliners - they'll be sitting on the ramp,
whining away, with the props stationary.

As I remember it, Gord was an FE on airplanes with the Allison T56.
That's a bit different - there's only one shaft, and the output to the
gearbox, compressor and turbine are all rigidly connected.
In that case, the whole engine turns at some serious RPM.
(Something like 13,000). A neat deal with teh T56 is that in flight,
it's basically a constant speed engine - the propeller pitch changes
to keep the RPM constant, while the torque varies, and the fuel
control varies the temperature to produce the desired torque.

> Take a google at a turbofan engine and you will see what I
> mean.
>
>
>> Most aircraft turbines driving props
>> rotate at 13,000 - 14,000 RPM and that's much too fast for props
>> so you need reduction gearing.
>
> You are a bit slow, the smaller engines turn around 40,000 rpm.
>
> Rick
>

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

[[email protected]]

(Peter Stickney) wrote:

>
>As I remember it, Gord was an FE on airplanes with the Allison T56.
>That's a bit different - there's only one shaft, and the output to the
>gearbox, compressor and turbine are all rigidly connected.
>In that case, the whole engine turns at some serious RPM.
>(Something like 13,000). A neat deal with teh T56 is that in flight,
>it's basically a constant speed engine - the propeller pitch changes
>to keep the RPM constant, while the torque varies, and the fuel
>control varies the temperature to produce the desired torque.
>

Yes...basically this is correct. The T-56 (as used) is a great
engine prop combination. As Peter says the engine/prop runs at
100% RPM all the time in flight. Basically you give it more or
less fuel to control the power. More fuel equals more temp which
(tries to) equal more rpm which equals more pitch which equals
more go. It's called a 'narrow band engine'.

Now the Napier Eland' which the T-56 replaced on Canada's Convair
440 (making it a 580) was a convoluted sob and was fully
understood by damned few aircrew (not to mention techs). I've won
quite a few beers with that engine. Get this now...the power
lever controlled (among other things) the prop pitch control (NOT
a CSU) setting which selected the prop to a COARSER pitch, so, as
power was added the prop would actually turn faster because of
the added torque but in spite of the coarser pitch. This devilish
arrangement was a bitch to keep in trim and required almost
constant tweaking.
--

-Gord.

[Alan Minyard]

On Thu, 08 Jan 2004 05:14:07 GMT, Rick > wrote:

wrote:
>
>> What aircraft would use that setup Rick? I can't imagine how you
>> could drive a prop directly from a turbine engine with no
>> reduction gearing? (or did I misread you?)
>
>I think you misread. A turboshaft engine can be used for
>anything but driving a propeller directly. They are used to
>power everything from generators and air compressors to
>ships and water pumps. Some of them, like the GE LM2500
>drive the output shaft directly from the power turbine at
>3600 rpm so they can be direct coupled to a generator. They
>do not use a gearbox.
>
>Rick

The LM2500 definitely has a reduction gear, and is not (in the USN)
used to power a generator. In most applications two LM2500 are
connected to a common reduction gear.

Al Minyard

[Alan Minyard]

On Thu, 08 Jan 2004 05:26:55 GMT, "Gord Beaman" ) wrote:

>Rick > wrote:
>
wrote:
>>
>>> What aircraft would use that setup Rick? I can't imagine how you
>>> could drive a prop directly from a turbine engine with no
>>> reduction gearing? (or did I misread you?)
>>
>>I think you misread. A turboshaft engine can be used for
>>anything but driving a propeller directly. They are used to
>>power everything from generators and air compressors to
>>ships and water pumps. Some of them, like the GE LM2500
>>drive the output shaft directly from the power turbine at
>>3600 rpm so they can be direct coupled to a generator. They
>>do not use a gearbox.
>>
>>Rick
>
>Ok, that makes sense as far as it goes...I'm a little surprised
>at the low speed of that turbine though but then, I'm used to
>aircraft turbines that rotate much faster, could be something to
>do with weight requirements though. The other part of your post
>seems to say that you 'can' drive a prop directly and that's what
>I was querying actually. Most aircraft turbines driving props
>rotate at 13,000 - 14,000 RPM and that's much too fast for props
>so you need reduction gearing.


You are right, the LM2500's are geared down, they operate
MUCH faster than a ships propeller, which is what they drive.

Al Minyard

[Rick]

Alan Minyard wrote:

> The LM2500 definitely has a reduction gear, and is not (in the USN)
> used to power a generator. In most applications two LM2500 are
> connected to a common reduction gear.

If by "most" you mean the numerical majority, most LM2500
installations are in power generation. A single engine
direct drives a generator.

Comparatively few of the engines are used for geared marine
propulsion systems.

Rick

[Rick]

Rick wrote:


> If by "most" you mean the numerical majority, most LM2500 installations
> are in power generation. A single engine direct drives a generator.
>
> Comparatively few of the engines are used for geared marine propulsion
> systems.


Oops, big foot in mouth, just found out there are about 300
more LM2500 engines in military use than civilian power
generation.

Don't know what percentage of the military installations are
geared propulsion though. Probably most of them.

Rick

[Abe]

In article >, ] says...
> In article >, Abe
> > wrote:
> >In article >,
> >says...
> >> A question-- why haven't any CAS aircrarft been designed with
> >> turboprops or the pusher varient (I foreget what you call it)?
> >
> >The Argentinian Pucara is/was a CAS aircraft with turboprops.
>
> The Pucara is usually denoted a COIN (Counter insurgency) aircraft.
> Flying one around a modern battlefield is going to be unhealthy.

Absolutely, which demonstrates nicely why turboprops aren't used in CAS
aircraft :)

[Kevin Brooks]

"Abe" > wrote in message
...
> In article >, ] says...
> > In article >, Abe
> > > wrote:
> > >In article >,
> > >says...
> > >> A question-- why haven't any CAS aircrarft been designed with
> > >> turboprops or the pusher varient (I foreget what you call it)?
> > >
> > >The Argentinian Pucara is/was a CAS aircraft with turboprops.
> >
> > The Pucara is usually denoted a COIN (Counter insurgency) aircraft.
> > Flying one around a modern battlefield is going to be unhealthy.
>
> Absolutely, which demonstrates nicely why turboprops aren't used in CAS
> aircraft :)

Gee, my text indicates there are two mission categories for air support of
ground forces--CAS and AI. No mention of "COIN". Which leads me to conclude
that COIN is not a mission per se, but more of a "condition set" for
missions--the actual missions in support of COIN operations would still be
CAS and AI.

Brooks

[[email protected]]

Rick > wrote:

>Rick wrote:
>
>
>> If by "most" you mean the numerical majority, most LM2500 installations
>> are in power generation. A single engine direct drives a generator.
>>
>> Comparatively few of the engines are used for geared marine propulsion
>> systems.
>
>
>Oops, big foot in mouth, just found out there are about 300
>more LM2500 engines in military use than civilian power
>generation.
>
>Don't know what percentage of the military installations are
> geared propulsion though. Probably most of them.
>
>Rick

Good man...I have much admiration for a person who, when he finds
himself in error, admits it. Good on you sir.
--

-Gord.

[Rick]

wrote:

> who, when he finds himself in error,

Thanks, but I am used to it ;-)

Rick

[[email protected]]

Rick > wrote:

wrote:
>
>> who, when he finds himself in error,
>
>Thanks, but I am used to it ;-)
>
>Rick

Yes, I suppose we who do it a lot, deserve less and less credit
as time goes on because it becomes easy for us but now if dudley
were to ever do it then he'd deserve a purple heart, a
ticker-tape parade and a national holiday created for him. Hell,
I even saw Rasimus do it recently. Excellent.
--

-Gord.

[Alan Minyard]

On Mon, 12 Jan 2004 03:42:20 GMT, Rick > wrote:

>Rick wrote:
>
>
>> If by "most" you mean the numerical majority, most LM2500 installations
>> are in power generation. A single engine direct drives a generator.
>>
>> Comparatively few of the engines are used for geared marine propulsion
>> systems.
>
>
>Oops, big foot in mouth, just found out there are about 300
>more LM2500 engines in military use than civilian power
>generation.
>
>Don't know what percentage of the military installations are
> geared propulsion though. Probably most of them.
>
>Rick

No problem, compared to some of my screw ups that was
VERY minor. :-)))

Al Minyard

[Penta]

On Mon, 12 Jan 2004 11:02:46 -0000, Abe > wrote:

>> >The Argentinian Pucara is/was a CAS aircraft with turboprops.
>>
>> The Pucara is usually denoted a COIN (Counter insurgency) aircraft.
>> Flying one around a modern battlefield is going to be unhealthy.
>
>Absolutely, which demonstrates nicely why turboprops aren't used in CAS
>aircraft :)

What, exactly, does a COIN aircraft DO, anyway? I know,
counterinsurgency...but that's not what I mean. How are they actually
used?

John

[Kevin Brooks]

"Penta" > wrote in message
...
> On Mon, 12 Jan 2004 11:02:46 -0000, Abe > wrote:
>
> >> >The Argentinian Pucara is/was a CAS aircraft with turboprops.
> >>
> >> The Pucara is usually denoted a COIN (Counter insurgency) aircraft.
> >> Flying one around a modern battlefield is going to be unhealthy.
> >
> >Absolutely, which demonstrates nicely why turboprops aren't used in CAS
> >aircraft :)
>
> What, exactly, does a COIN aircraft DO, anyway? I know,
> counterinsurgency...but that's not what I mean. How are they actually
> used?

Generally, just like any other combat aircraft--they would perform CAS or
air interdiction operations. COIN is not a mission--it is merely different
set of conditions under which you execute your combat operations.

Brooks

>
> John