Modern day propeller fighter - hypothetical

Some of the latest developments in propeller aircraft has fascinated
me. It also brought up an interesting hypothetical question; mostly
when reading about modern day warbird replicas.

With relatively easily available technology off the shelf (no rail
guns or laser cannon please). Lets say a reasonable development budget
of oh say $300 million. The question is are we capable of producing
superior prop aircraft than the great fighters of WWII and what
configuration would it take?

To keep the discussion relatively focused we'll put in a couple of
rules:

1. Mission: Air superiority/dominance during WWII. Land based. It
should be able to clear the skies of any and all opposition at all
ranges and altitudes.

2. Must be a propeller aircraft.

3. Only armanent allowed are guns/cannons. No guided missiles. I guess
dumb firing rockets will be ok since they were used during WWII.


With the above two exceptions all of modern technology is allowed to
be used for example composite materials, radars, titanium armour,
fly-by-wire (will dynamic instability benefit the agility of a prop
plane?) advanced aerodynamic configurations (rear mounted engines). To
make matters really intesting helicopters are fine. Just as long as
the driving force isn't a jet.

If we were to design a new prop, gun armed aircrafy would it
essentially look pretty similar to a carbon fibre, turbo-prop P-51
Mustang or would it be some bizzare split wing, dual rear engined
travesty?

regards,


Nev

"Nev" wrote in message
...
Some of the latest developments in propeller aircraft has fascinated
me. It also brought up an interesting hypothetical question; mostly
when reading about modern day warbird replicas.

With relatively easily available technology off the shelf (no rail
guns or laser cannon please). Lets say a reasonable development budget
of oh say $300 million. The question is are we capable of producing
superior prop aircraft than the great fighters of WWII and what
configuration would it take?

Su we have nearly sixty years of additional power, aerodynamic,
explosive, fusing, gun, electronics and materials research to draw upon.

To keep the discussion relatively focused we'll put in a couple of
rules:

1. Mission: Air superiority/dominance during WWII. Land based. It
should be able to clear the skies of any and all opposition at all
ranges and altitudes.

2. Must be a propeller aircraft.

I assume you mean to allow turboprops. If you stick to piston
engined planes you'll blow your budget trying to recreate the
engine base.

3. Only armanent allowed are guns/cannons. No guided missiles. I guess
dumb firing rockets will be ok since they were used during WWII.


With the above two exceptions all of modern technology is allowed to
be used for example composite materials, radars, titanium armour,
fly-by-wire (will dynamic instability benefit the agility of a prop
plane?) advanced aerodynamic configurations (rear mounted engines).

Gun sights tied to radars and computers would be "death dot" types.
Gatling gun or high speed revolver would shred any WWII fighter in
a second.

To make matters really intesting helicopters are fine. Just as long as
the driving force isn't a jet.

Helicopters are not suitable for the mission: less than half the
needed speed.

If we were to design a new prop, gun armed aircrafy would it
essentially look pretty similar to a carbon fibre, turbo-prop P-51
Mustang or would it be some bizzare split wing, dual rear engined
travesty?

Depends on who does the designing: Rutan would make something
bizarre.

I'ld guess you'd end up with an all weather plane between a P-38
and P-61 in size. Likely twin turbo prop to free up the center
line for radar and the gun. Slightly sweep wing and aerodynamics
to give a top speed something better than 550mph. Engines and pilot
virtually proofed against any air fighter guns of the period and
the rest pretty robust.
Boom & zoom tactics, blast one and blow through, reposition and
repeat. Superior speed and targeting makes it mighty attractive.

Or heck, something bigger but with a CIWS or two mounted, then
you would even have to point the nose at'em.

John Keeney wrote:

snip

I'ld guess you'd end up with an all weather plane between a P-38
and P-61 in size. Likely twin turbo prop to free up the center
line for radar and the gun.

A couple of alternatives for the centerline gun

- Through the prop hub as per WWII engine mounted guns (wasn't the original
idea for a 20mm Birket/hispano like this from WWI?).

- Rear engine as per some studies for CAS in the 80s, BA?

Or both as per Dornier 335, hmmm 2 x Bear engines (15,000hp each) might be a
bit much. Or maybe the Voyager idea of 2 different powers, one small for
cruise efficiency and range with a bigger one for combat (oil etc
preheated). The cruise engine optimised for cruise at FL300+ should give
good range together with some protection from flak and being bounced (A
nice preliminary study for a mere 100K, recommending a more detailed
study).

For combat alpha and beta pitch could be used on one or two to control
acceleration/deceleration without spool up time. Single power lever of
course.

The main limit to power would probably be prop problems with precession
during violent manouvering being only one.

Radar could be wing mounted with electronic correction for night/cloud
sighting.

Trike gear would be essential even for a single engine, the ground loop rate
was bad enough at WWII p/w ratios let alone with p/w x 2+ and the sort of
ground angle required by biggerprops. A Pitts with 1,000hp might be a bit
of a handfull.

I suspect 300M might be a bit low for development now. The Australian Wamira
trainer from the early 80's chewed up AUD70M before cancellation before
flight, there were many reasons spec changes being the main one To give one
exanple, had to be side by side, had to be tandem, other people might want
the other so has to be either!!!. Instead the PC9 (pre Texan II) was
bought, this is roughly equivalent to the Bf109A, Spit 1, P40A in
performance.

AFAIK the PC9 and Texan II are loosely derived from the Bf109, although no
common parts, the chain went, Bf109 begat the lower powered PC3 trainer
(cheaper to operate and better manners) then the PC7, PC9 and Texan II went
through an incremental process of desired handling and MORE GRUNT.

regards

jc

On Thu, 04 Dec 2003 02:07:05 +1100, wrote:

John Keeney wrote:

snip

I'ld guess you'd end up with an all weather plane between a P-38
and P-61 in size. Likely twin turbo prop to free up the center
line for radar and the gun.

A couple of alternatives for the centerline gun

- Through the prop hub as per WWII engine mounted guns (wasn't the original
idea for a 20mm Birket/hispano like this from WWI?).

- Rear engine as per some studies for CAS in the 80s, BA?

Or both as per Dornier 335, hmmm 2 x Bear engines (15,000hp each) might be a
bit much.

I imagine it might be a bit large too :-)

On Thu, 04 Dec 2003 16:37:38 GMT, Scott Ferrin
wrote:


Or both as per Dornier 335, hmmm 2 x Bear engines (15,000hp each) might be a
bit much.

I imagine it might be a bit large too :-)

Make for interesting an interesting piece of flying boom refuelling also.


greg

--
In the beginning. Back in nineteen fifty-five
Man didn’t know about a rock ’n’ roll show
And all that jive.

In article ,
Scott Ferrin wrote:

On Thu, 04 Dec 2003 02:07:05 +1100, wrote:

John Keeney wrote:

snip

I'ld guess you'd end up with an all weather plane between a P-38
and P-61 in size. Likely twin turbo prop to free up the center
line for radar and the gun.

A couple of alternatives for the centerline gun

- Through the prop hub as per WWII engine mounted guns (wasn't the original
idea for a 20mm Birket/hispano like this from WWI?).

- Rear engine as per some studies for CAS in the 80s, BA?

Or both as per Dornier 335, hmmm 2 x Bear engines (15,000hp each) might be a
bit much.

I imagine it might be a bit large too :-)

Just how long would the main gear have to be?

Nev wrote:
1. Mission: Air superiority/dominance during WWII. Land based. It
should be able to clear the skies of any and all opposition at all
ranges and altitudes.

2. Must be a propeller aircraft.

3. Only armanent allowed are guns/cannons. No guided missiles. I guess
dumb firing rockets will be ok since they were used during WWII.

How about a Pucara?

Cheers
David

On 2 Dec 2003 20:05:13 -0800, (Nev) wrote:



2. Must be a propeller aircraft.


Shame, A skyraider, a CFM56 and a crowbar came to mind LOL.


greg

--
In the beginning. Back in nineteen fifty-five
Man didn’t know about a rock ’n’ roll show
And all that jive.

The question is are we capable of producing
superior prop aircraft than the great fighters of WWII and what
configuration would it take?

I'm not sure what the engine would be. Is there an off-the-shelf
turbine engine that could be tweaked to the war-emergency power
requirements of a fighter aircraft?

I'm not saying there is none! I haven't the faintest idea of what the
capabilities of existing turbines might be. But note that the
horsepower of front-line fighters in WWII was more than doubled in
four years, as an example of wartime requirements. Also, lives were
cheaper in those days. The Germans accepted a man-killer like the Me
163 into front-line service, and the Me 262 would also be unacceptable
today, with its 10-hour engine life.


all the best -- Dan Ford
email:

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

"Cub Driver" wrote in message
...

The question is are we capable of producing
superior prop aircraft than the great fighters of WWII and what
configuration would it take?

I'm not sure what the engine would be. Is there an off-the-shelf
turbine engine that could be tweaked to the war-emergency power
requirements of a fighter aircraft?

I'm not saying there is none! I haven't the faintest idea of what
the
capabilities of existing turbines might be. But note that the
horsepower of front-line fighters in WWII was more than doubled in
four years, as an example of wartime requirements. Also, lives were
cheaper in those days.

The Germans accepted a man-killer like the Me
163 into front-line service, and the Me 262 would also be
unacceptable
today, with its 10-hour engine life.

The engine entered service with an MTBO of 25 hours which was well
established. (about 16 missions) Manufacturing complaince and service
realities degraded this to 10 hours for a while. Still if I was an
Ju 88 pilot I'd prefer converting to the Jet than the Me 109 given
that my combat skills and the concentraion of allied aircraft.

Mean time between overhall was 25 hours not total engine life and was
a problem of lack of chromium and particularly nickel at one level and
at another level poor manufacturing quality control compliance. (This
made the biggest difference; the use of unskilled factory labour
versus technicians and tradesmen who did not need supervision or
detail instructions)

Injector burners were the most heavily consmed item but could be
easily replaced.

The 6 Combustion chambers were made of simple carbon steel coated in
aluminium and needed to be replaced at 25 hours.

Both the hollow air cooled tinadur and cromadure turbine blades were
removed at 25 hours, x-rayed and if OK replaced for a further 10
hours.

Theoreticaly engine overhaul life reached 60 hours in the latter model
s.

Earlier engines, the Jumo 004B1 had solid blades while the Jumo 004B4
had hollow aircooled blades and was more reliable. The first
experimental blades had lives of 4 hours to over 100 hours due to
manufacturing spread.

What the Jumo 004B lacked was a throttle bypass system to bypass
excess fuel as the compressor spooled up. The control system did rely
on RPM and pressure but this was inadaquete in cases of rapid throttle
movement. The over supply of fuel could raise combustion temperatures
by 200C which had the effect of burning through combustion chambers
and turbines.

The BMW 003A used on the Arado 234C and He 162 volksjaeger despite
lagging 9 months behined and actualy having its control system derived
from the Junkers model was more sophisticated in having a throttle
bypass system.

The annular combustion chamber on the BMW 003A lasted 200 hours, the
turbine could be removed, inspected and replaced in less than 2
hours, the engine did have a throttle limiting system. Unlike the 004
the engine did not need to be stripped down.

The Jumo 004C and Jumo 004D both entered production (for use in
prototypes) and had increased thrust of 1050 and 1100kg due to detail
refinements. In the case of the 004D this included duel zone
combustion to overcome the atomisation problems that cuased flameouts
at high altitude and idling. (These engines all entered production
but not service. A Jumo 004C apparently propelled an Me 262 to
584mph.)

Part of the problem the engineers faced was the fuel. Although
designed for running on the diesel based J2 fuel for reasons of
economy and safety this added a 2 stage startup initialy on a lighter
fuel as well as necesitating fuel systems that could cope.

Some Me 262 missions were flown with crude oil in the tanks. The
crude oil was refined only by centrifuge, then heated and pumped into
the tanks.





all the best -- Dan Ford
email:

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