Survivability in Combat

Subject: Survivability in Combat
From: "The Enlightenment"
Date: 12/7/03 5:12 AM Pacific Standard Time
Message-id:


"ArtKramr" wrote in message
...
Let's take two planes going on low level support missions. They will
have to
fly through heavy ground fire including small arms fire. One plane
is equipped
with a radial engine,. let's say an R-2800. The other with a jet
engine. Which
plane would have a better chance of survival inder these
conditions?. Opinions?

Regards,


Arthur Kramer
344th BG 494th BS
England, France, Belgium, Holland, Germany
Visit my WW II B-26 website at:
http://www.coastcomp.com/artkramer



Much of the Structure of a Gas turbine is thinner than that of the
rugged engine blocks, cylinder and heads required on piston engines
and thus penetration into a vital component by projectiles may be more
likely however gas turbines can be quite tough. The central casting
of which the shaft and combustion chambers are suspended is quite
solid and centrifugal compressors can be very rugged.

It might be possible to obtain data as to how influential compressor
type is on combat ruggedness.

I suppose that the best comparison might be to assume an aircraft such
as the B26,A26 or B29 had of been equipped with a turboprop like the
Rolls Royce Dart. (Fokker when designing the F27 (built latter by
Fairchild) resisted American Airlines's pressure to use the PW2800.)

This engine would have about 1/2rd the weight and I suspect 1/2 to
volume of the PW2800 and this in itself would reduce its chance of
being hit. The two stage centrifugal compressor was very rugged and
for the weight saved you could wrap the engine in armor.

The Allison T53 gas turbine used on the UH-1 Iroquois and many other
aircraft had a reputation for ruggedness. It kept operating with
objects like bolts ingested and stuck in the compressor. This engine
had as a first stage an axial compressor, a second stage centrifugal
stage that led to a double reverse flow combustion chamber.

The Germans seemed to have had a concern with debris ingestion
(presumably after a hit on a target) in the Jumo 004B engine of the
Me 262. For ground handling and safety reasons wire baskets had been
developed to prevent unfortunate ground crewman being ingested. The
aircraft was tested in flight with the baskets attached and apparently
suffered no reduction in performance.

The concern of 'combat ruggedness' was one reason that the RLM
technocrat Helmuth Schelp (who mapped out Germany's 15 year gas
turbine development program in 1938?) specified that the Heinkel
Hirth He S11 1300kg turbo-jet was to have a 'diagonal compressor'.
This is essentially a centrifugal compressor faired such that the air
flow exits axially (backward) instead of radialy (outward). The air
is then impinged upon a stator to get a degree of axial compression.
In the He S11 there were then 3 subsequently axial stages.

The beauty is that the ruggedness of centrifugal compressor in object
ingestion and turbulent airflow as a first stage can be combined with
subsequently more axial stages of higher efficiency. (Thus He S11
aircraft designees had very flexible air intake shapes e.g. slits in
wing leading edges )

The efficiency at the operating point for the axial unit of the Jumo
004B was 0.79. For the hybrid diagonal-axial He S11 it was 0.8. By
the time the He S11 entered production in 1945 the diagonal compressor
for the BMW 003C the HERMESO I was achieving 0.85 on the test stand
and the HERMESO II of the BMW 004D was expected to achieve 0.91. (By
this time the Germans were converting to more efficient reaction type
axial compressors over the impulse type axial seen on the Jumo 004B
and BMW 003A then in service) so they sacrificed a lot to achieve this
diagonal/compressor on the He S11.

The British style centrifugal compressors, the double sided impeller
types, must have been much more rugged than the axial types they
Germans preferred (for their low frontal area and ease of
installation)

However a shrapnel or bullet hole in the post combustion area of a
combustion chamber in either type of engine would have been fatal as a
flame would be expelled that would eventually melt or burn through
something. A holed combustion chamber or rocker cover was unlikely
to be fatal in an air cooled radial.

The answer clearly is to try and armor parts of the Jet engine, e.g.
the Chance Vought A7 used silicon carbide. Jets are free of the
oil.water cooler problems of piston engines.



Lots of good info. Thanks. I woiuld love to hear the take on all this by a
pilot who flew Jugs in WW II in low level operations then flew jets later and
hear comparative opinions. Any jugheads around here?

Regards,

Arthur Kramer
344th BG 494th BS
England, France, Belgium, Holland, Germany
Visit my WW II B-26 website at:
http://www.coastcomp.com/artkramer

In message , ArtKramr
writes
Let's take two planes going on low level support missions. They will have to
fly through heavy ground fire including small arms fire. One plane is equipped
with a radial engine,. let's say an R-2800. The other with a jet engine. Which
plane would have a better chance of survival inder these conditions?. Opinions?

My gut feeling is the jet, if only because it's faster and spends less
time being shot at (and the higher deflection makes it harder to hit).
Also, jet aircraft can be pretty tough; stories around about them
surviving assorted insults (going as far as F-105s flying with destroyed
engines, using the afterburner as a sort-of-ramjet) so the survivability
between a jet and a radial recip isn't as pronounced.

After all, either aircraft is equally at risk from hits to pilot,
control surfaces, fuel tanks et cetera... superior survivability of the
engine is a factor, but not the only one (vice the use of P-51s rather
than P-47s in Korea)

--
When you have to kill a man, it costs nothing to be polite.
W S Churchill

Paul J. Adam MainBoxatjrwlynch[dot]demon{dot}co(.)uk

On Sun, 7 Dec 2003 16:56:41 +0000, "Paul J. Adam"
wrote:

In message , ArtKramr
writes
Let's take two planes going on low level support missions. They will have to
fly through heavy ground fire including small arms fire. One plane is equipped
with a radial engine,. let's say an R-2800. The other with a jet engine. Which
plane would have a better chance of survival inder these conditions?. Opinions?

My gut feeling is the jet, if only because it's faster and spends less
time being shot at (and the higher deflection makes it harder to hit).
Also, jet aircraft can be pretty tough; stories around about them
surviving assorted insults (going as far as F-105s flying with destroyed
engines, using the afterburner as a sort-of-ramjet) so the survivability
between a jet and a radial recip isn't as pronounced.

After all, either aircraft is equally at risk from hits to pilot,
control surfaces, fuel tanks et cetera... superior survivability of the
engine is a factor, but not the only one (vice the use of P-51s rather
than P-47s in Korea)

Seems to me that you need to define a lot of additional parameters
before you can reduce the discussion to whether a radial is more
survivable than a jet.

If you say same speed, same profile, same airframe, same tactics, same
thrust(power) to weight, same performance, then I'd go to the radial
engine as being one that sustains a bit more insult. But, we've not
added the factor (significant in my mind) about the volatility of
AvGas over JP-4 (JP-8). Wet wing airplane taking a hit in the fuel
tanks? Not pretty.

But, if you let your jet go faster, pull more G, maneuver more
aggressively, build a tactics package that suppresses the defenses,
etc. then you come up with the undebatable conclusion that the jet
does better.

Have I ever mentioned that FAST is better?

"Cub Driver" wrote in message
...
On Sun, 07 Dec 2003 02:15:49 GMT, "Dudley Henriques"
wrote:

International Fighter Pilots Fellowship
Commercial Pilot/ CFI Retired

Dudley, would you post a brief bio for us? I think I recall P-51s, but
I don't have any notion of your career. When were you in the
USAF/USAAF? For whom a commercial pilot? Where taught?

I am a civilian pilot Ford, not military. Obviously you haven't yet done
enough research. Lots of public record on this.

How and why I have flown military airplanes is none of your business.

Although I can't stop you from going down the road I believe you're thinking
of going with this, I will tell you that I don't like this type of post .
Do your own legwork Ford. There are many sources of public information on
me, and what's not there, I have no desire to share with someone as
obviously hostile to me as you are with this post.
I sincerely hope I'm wrong in what I'm reading from your post here. If I am,
please feel free to dig up and post anything you wish that's public
information on me. If I'm not wrong, I feel compelled to advise you to be
extremely careful where you go with this in a public forum.
Your call !
Dudley Henriques
International Fighter Pilots Fellowship
Commercial Pilot/ CFI Retired
For personal email, please replace
the z's with e's.
dhenriquesATzarthlinkDOTnzt





Dudley Henriques
International Fighter Pilots Fellowship
Commercial Pilot/ CFI Retired
For personal email, please replace
the z's with e's.
dhenriquesATzarthlinkDOTnzt

From: "Dudley Henriques"

"Cub Driver" wrote in message

Dudley, would you post a brief bio for us? I think I recall P-51s, but
I don't have any notion of your career. When were you in the
USAF/USAAF? For whom a commercial pilot? Where taught?

I am a civilian pilot Ford, not military. Obviously you haven't yet done
enough research. Lots of public record on this.

How and why I have flown military airplanes is none of your business.

Although I can't stop you from going down the road I believe you're thinking
of going with this, I will tell you that I don't like this type of post .
Do your own legwork Ford. There are many sources of public information on
me, and what's not there, I have no desire to share with someone as
obviously hostile to me as you are with this post.
I sincerely hope I'm wrong in what I'm reading from your post here. If I am,
please feel free to dig up and post anything you wish that's public
information on me. If I'm not wrong, I feel compelled to advise you to be
extremely careful where you go with this in a public forum.
Your call !
Dudley Henriques
International Fighter Pilots Fellowship
Commercial Pilot/ CFI Retired
For personal email, please replace
the z's with e's.
dhenriquesATzarthlinkDOTnzt

Dudley Henriques

Am I missing something here? I see nothing "hostile" in the request. I also see
nothing wrong with simply saying "I'd rather not say" as a response.

Dan, U. S. Air Force, retired

Subject: Survivability in Combat
From: "Leslie Swartz"
Date: 12/6/03 8:02 PM Pacific Standard Time
Message-id:

Speed is life.

But no gaurantees. Witness all those suiperfast planes lost in battle while
going superfast.

Regards,

Arthur Kramer
344th BG 494th BS
England, France, Belgium, Holland, Germany
Visit my WW II B-26 website at:
http://www.coastcomp.com/artkramer

How and why I have flown military airplanes is none of your business.

Sheez. We're supposed to sit here awestruck at the Fighter Pilot
Fellowship, but we can't inquire as to how and why you flew military
airplanes?

Dudley, there is something fishy about you.


all the best -- Dan Ford
email:

see the Warbird's Forum at www.warbirdforum.com
and the Piper Cub Forum at www.pipercubforum.com

Subject: Survivability in Combat
From: Ed Rasimus
Date: 12/7/03 9:59 AM Pacific Standard Time

Let's take two planes going on low level support missions. They will have
to
fly through heavy ground fire including small arms fire. One plane is
equipped
with a radial engine,. let's say an R-2800. The other with a jet engine.
Which
plane would have a better chance of survival inder these conditions?.
Opinions?

My gut feeling is the jet, if only because it's faster and spends less
time being shot at (and the higher deflection makes it harder to hit).
Also, jet aircraft can be pretty tough; stories around about them
surviving assorted insults (going as far as F-105s flying with destroyed
engines, using the afterburner as a sort-of-ramjet) so the survivability
between a jet and a radial recip isn't as pronounced.

After all, either aircraft is equally at risk from hits to pilot,
control surfaces, fuel tanks et cetera... superior survivability of the
engine is a factor, but not the only one (vice the use of P-51s rather
than P-47s in Korea)

Seems to me that you need to define a lot of additional parameters
before you can reduce the discussion to whether a radial is more
survivable than a jet.

If you say same speed, same profile, same airframe, same tactics, same
thrust(power) to weight, same performance, then I'd go to the radial
engine as being one that sustains a bit more insult.

My inquiry was only about engines. Thanks.


But, we've not
added the factor (significant in my mind) about the volatility of
AvGas over JP-4 (JP-8). Wet wing airplane taking a hit in the fuel
tanks? Not pretty.


I had not included wing design in my orignal question.


But, if you let your jet go faster, pull more G, maneuver more
aggressively, build a tactics package that suppresses the defenses,

Tactics packages that supress defenses vary in their effectiveness and there
are never any guarantees.

etc. then you come up with the undebatable conclusion that the jet
does better.

No issue is undebateable.

Have I ever mentioned that FAST is better?


Yes Fast is better has merit, But there are no gaurantees. There are never
gaurantees, Thanks for the input.

Regards,



Arthur Kramer
344th BG 494th BS
England, France, Belgium, Holland, Germany
Visit my WW II B-26 website at:
http://www.coastcomp.com/artkramer

(B2431) wrote:

From: "Dudley Henriques"

"Cub Driver" wrote in message

Dudley, would you post a brief bio for us? I think I recall P-51s, but
I don't have any notion of your career. When were you in the
USAF/USAAF? For whom a commercial pilot? Where taught?

I am a civilian pilot Ford, not military. Obviously you haven't yet done
enough research. Lots of public record on this.

How and why I have flown military airplanes is none of your business.

Although I can't stop you from going down the road I believe you're thinking
of going with this, I will tell you that I don't like this type of post .
Do your own legwork Ford. There are many sources of public information on
me, and what's not there, I have no desire to share with someone as
obviously hostile to me as you are with this post.
I sincerely hope I'm wrong in what I'm reading from your post here. If I am,
please feel free to dig up and post anything you wish that's public
information on me. If I'm not wrong, I feel compelled to advise you to be
extremely careful where you go with this in a public forum.
Your call !
Dudley Henriques
International Fighter Pilots Fellowship
Commercial Pilot/ CFI Retired
For personal email, please replace
the z's with e's.
dhenriquesATzarthlinkDOTnzt

Dudley Henriques

Am I missing something here? I see nothing "hostile" in the request. I also see
nothing wrong with simply saying "I'd rather not say" as a response.

Dan, U. S. Air Force, retired

Touchy lil ****er ain't he?...
--

-Gord.

"The Enlightenment" wrote in message ...
"ArtKramr" wrote in message
...
SNIP
..
The efficiency at the operating point for the axial unit of the Jumo
004B was 0.79. For the hybrid diagonal-axial He S11 it was 0.8. By
the time the He S11 entered production in 1945 the diagonal compressor
for the BMW 003C the HERMESO I was achieving 0.85 on the test stand
and the HERMESO II of the BMW 004D was expected to achieve 0.91. (By
this time the Germans were converting to more efficient reaction type
axial compressors over the impulse type axial seen on the Jumo 004B
and BMW 003A then in service) so they sacrificed a lot to achieve this
diagonal/compressor on the He S11.


There is a typing mistake in my above post. All the compressors of
the BMW003 series were axial NOT diagonal.

The BMW 003A (the 4 jet engines of which used on the Arado 234C and in
its BMW003E dorsal mount form as on the Heinker He162
Salamander/VolksJaeger) in fact had an axial type compressor. This
compressor was an axial "impulse" type in which the compression is
carried out by the turbine blades and the stator merely serves to
guide the airflow. The BMW 003A produced 800kg thrust.

To increase thrust without increasing fuel consumption ABB developed
for the BMW 003C an axial compressor known as the HERMESO I. The was
of the "reaction type" in which more precise machined blades provide
around 50% of the compression. The result is higher efficiency in the
case of HERMESO I this was 0.84 Thus the BMW 003C achieved the same
thrust as the Jumo 004B with the samller weight, fuel cosumption of
the already good BMW003.

The BMW 003D had the refined HERMES0 II with a bench tested efficiency
of 0.91. The engine was expected to have a thrust of 1100kg and to be
used on on range recon versions of the Arado 234. For combat the
tougher 1300kg thrust He S11 with its diagonal compressor was seen as
superior.