Modern day propeller fighter - hypothetical

[Nev]

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

In article >,
(Nev) wrote:

> The question is are we capable of producing
> superior prop aircraft than the great fighters of WWII..?


probably not.

new prop planes have been designed for modern air forces, but these are
made to different specifications. these planes might be used for
missions that require slow speeds, such as reconnaissance. or they are
built for low-budget customers- not at all the high performance
machines that you are looking for.

the task then becomes a question of engineering man-hours. you would
begin by identifying modern materials and devices that are superior to
what existed 60 years ago. this is the easy part.

then you would have to start designing and testing ways to use your
21st century technology for this 20th century application. that would
be the hard part.

let's say you actually did this, hired a team of good engineers to
spend millions of dollars on the question and started manufacturing the
results. the odds are that your effort would still fall short.

during wwii, the best minds of the entire world were devoted to this
question. the large scale use of these planes allowed a great deal of
trial-and-error refinement. there would be no similar opportunity in
the modern world.

to get the real-world testing, you would have to hypnotize everyone on
the planet to forget jet technology, but to not forget any other
technology that might contribute to this issue. then get everyone in a
big war again so you can sit back and observe the results.

the question rapidly becomes too silly to consider.

[John Keeney]

"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?

Sure: 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.

[David Bromage]

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

[Greg Hennessy]

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.

[Cub Driver]

>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

[tscottme]

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.
>

Why is being prop-driven a requirement, afraid the people on the ground
will fall asleep during aircraft operations? Using a prop limits the
aircraft to much lower airspeeds than current fighters. I think there's
been one or two exotic birds that have operated about Mach 1

Why not build an air-superiority fighter with an open cockpit?

--

Scott
--------
Monitor the latest efforts of "peaceful Muslims" at
http://www.jihadwatch.org/

[[email protected]]

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

[John Bailey]

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

>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.
>
>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.

Take one Kuznetsov NK-12MV turboprop giving 14,795 shp as used in the
Tupolev 95 Bear. With four engines the Bear gave: 575 mph (925 km/h)
Ceiling: 39,370 ft (12000 m) For a single engine fighter, it should be
able to cruise climbing straight up. An even more mind boggling
configuration would be two NK-12MV's in a twin boom design, a la the
P-38.

The real value of this design would be using the TU-95's transonic
counter-rotating propellers, which probably provide an upper limit on
speed.

Come to think of it, the single engine version would probably resemble
the Convair XFY-1, Pogo. POWERPLANT: One Allison YT40-A-6 turboprop
(which consisted of two T38 turboprops coupled together) driving a
pair of Curtiss-Wright 16-foot three-bladed contra-rotaing propellers
in the nose.

Specifications of Convair XFY-1 Pogo: (From
http://home.att.net/~jbaugher4/fypogo.html)

Engines: One Allison XT40-A-6 turboprop, rated at 5500 shp. Projected
performance with the 6955 ehp XT40-A-16: Maximum speed: 610 mph at
15,000 feet, 592 mph at 35,000 feet. Initial climb rate 10,500
feet/minute. An altitude of 20,000 feet could be attained in 2.7
minutes, 30,000 feet in 4.6 minutes. Service ceiling 43,700 feet.
Endurance was one hour at 35,000 feet. Weights: 11,760 pounds empty,
16,250 pounds gross. Dimensions: wingspan 27 feet 7 3/4 inches, length
34 feet 11 3/4 inches, vertical span 22 feet 11 inches, wing area 355
square feet. Armament was to have consisted of four 20-mm cannon or 48
2 3/4 FFARs


John Bailey
http://home.rochester.rr.com/jbxroads/mailto.html

[Chad Irby]

In article >,
(John Bailey) wrote:

> On 2 Dec 2003 20:05:13 -0800, (Nev) wrote:
>
> >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.
> >
> >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.
>
> Take one Kuznetsov NK-12MV turboprop giving 14,795 shp as used in the
> Tupolev 95 Bear. With four engines the Bear gave: 575 mph (925 km/h)
> Ceiling: 39,370 ft (12000 m) For a single engine fighter, it should be
> able to cruise climbing straight up. An even more mind boggling
> configuration would be two NK-12MV's in a twin boom design, a la the
> P-38.
>
> The real value of this design would be using the TU-95's transonic
> counter-rotating propellers, which probably provide an upper limit on
> speed.

A better config for a "modern" prop fighter could be a very beefy
version of the Japanese Shinden interceptor. Pusher prop, swept wing,
canard. A larger version of this, with a 20mm gatling in the belly and
a radar in the nose?

<http://www.eagle.ca/~harry/aircraft/shinden/>

Scale that sucker up by 50% or so in each direction, put a big engine
and some weapons in it, and there ya go...

If you're in love with a twin boom aircraft, dig out the plans for the
P-61 Black Widow. Lots of room for guns (it already has a radome and a
seat for an operator), extremely good handling for a plane that size,
and you could even keep the turret with a minigun or two.

Stick a couple of 20 mm gatlings in the belly, crank up some advanced
engines (modern turboprops would give it about *five* times as much
power), and have fun.

--
cirby at cfl.rr.com

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

[The Enlightenment]

"John Bailey" > wrote in message
...
> On 2 Dec 2003 20:05:13 -0800, (Nev) wrote:
>
> >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.
> >
> >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.
>
> Take one Kuznetsov NK-12MV turboprop giving 14,795 shp as used in
the
> Tupolev 95 Bear. With four engines the Bear gave: 575 mph (925 km/h)
> Ceiling: 39,370 ft (12000 m) For a single engine fighter, it should
be
> able to cruise climbing straight up. An even more mind boggling
> configuration would be two NK-12MV's in a twin boom design, a la the
> P-38.
>
> The real value of this design would be using the TU-95's transonic
> counter-rotating propellers, which probably provide an upper limit
on
> speed.
>

Those sorts of performances I think were achievable with piston
engines.

The Luft46 web site lists a few German pusher prop aircraft that were
projected as replacements for then current Lufwaffe aircraft.
Achieving as much as 584 mph on an ordinary 1750HP Jumo 213 V12 piston
engine seems to have been accepted.

This scimitar prop aircraft is one of the fastest at 584mph.
http://www.luft46.com/dornier/dop252.html

The advantage would be fuel efficiency and the lack of refractory
alloys needed for the engine. The cost of making high octane fuel is
exorbitant compared to make Jet fuel.

I recall seeing GE tested scimitar shaped pusher prop engines, I think
it was on a 727.

[The Enlightenment]

"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

[George Ruch]

(Nev) wrote:

>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?

[snip]

>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?

Bizarre, hardly. Have you taken a look at the Beech Starship?

http://www.bobscherer.com/Pages/Starship.htm and
http://www.brunton.net/starship.html

Seems like that would be a reasonable starting point for such a fighter.
Advanced composite construction, modern avionics and flight controls, and
sexy as hell.

/------------------------------------------------------------\
| George Ruch |
| "Is there life in Clovis after Clovis Man?" |
\------------------------------------------------------------/

[B2431]

>From: "The Enlightenment"
>
<snip>
>
>I recall seeing GE tested scimitar shaped pusher prop engines, I think
>it was on a 727.
>
I seem to recall it being on the right engine of a DC-9. I wonder what became
of that idea.

Dan, U. S. Air Force, retired
>
>
>
>
>

[Peter Stickney]

In article >,
"The Enlightenment" > writes:
> Those sorts of performances I think were achievable with piston
> engines.
>
> The Luft46 web site lists a few German pusher prop aircraft that were
> projected as replacements for then current Lufwaffe aircraft.
> Achieving as much as 584 mph on an ordinary 1750HP Jumo 213 V12 piston
> engine seems to have been accepted.

Quite frankly, that's bat****.
<cue the every 3 months lecture on the Speed/Power relationship for
the thrust of propeller driven airplanes.>
To cut to the chase - a constnt power output engine, like a recip, or
the propeller side of a turboprop, produces less thrust the faster you
go. Assuming 85% propeller efficiency across the board, your 1750 HP
Jumo is producing 2790# of thrust at 200 mph, 1490# of thrust at 375
mph, and at 584 mph, 955# of thrust. (It's actually a lot worse than
that - the efficiency of the prop goes way down beyond about 450-500
mph at Sea Level.

> This scimitar prop aircraft is one of the fastest at 584mph.
> http://www.luft46.com/dornier/dop252.html

Even assuming that there are _no_ transonic effects on the airframe
(Which there will be), and two engines, the Equivalent Profile Area of
the drawing below is 3.55 sq ft. (That's Drag Coefficient * Reference
Area).
A P-51 works out to a profile area of about 4.66 ft.
This Dornier cattywampus is more that twice the size of a P-51.
The claims are rediculouss on the face of it. The SS Scientific Branch
might believe such horse****, but real life physics wins every time.


(And the Scientific Branch certainly _did_ believe such horse****.
They sent a specialist in Infrared Photography to Spitzbergen to
photograph the British Home Fleet at Scapa Floe through the Hole into
the Hollow Earth.)

> The advantage would be fuel efficiency and the lack of refractory
> alloys needed for the engine. The cost of making high octane fuel is
> exorbitant compared to make Jet fuel.

> I recall seeing GE tested scimitar shaped pusher prop engines, I think
> it was on a 727.

And it wasn't operating at 85% efficency at that Mach Number, either.
The thrust numbers I posted above are best case.

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

[George Ruch]

(B2431) wrote:

>>From: "The Enlightenment"
>>
><snip>
>>
>>I recall seeing GE tested scimitar shaped pusher prop engines, I think
>>it was on a 727.
>>
>I seem to recall it being on the right engine of a DC-9. I wonder what became
>of that idea.

I remember what may be the same picture, a DC-9 fitted with a high-bypass
turbofan, and multiple scimitar-shaped fan blades extending from the
first-stage fan. Damned if I can find it now, though. Nothing like it so
far on the NASA Dryden site. Any other ideas?

/------------------------------------------------------------\
| George Ruch |
| "Is there life in Clovis after Clovis Man?" |
\------------------------------------------------------------/

[Chad Irby]

In article >,
George Ruch > wrote:

> (B2431) wrote:
>
> >>From: "The Enlightenment"
> >>
> ><snip>
> >>
> >>I recall seeing GE tested scimitar shaped pusher prop engines, I think
> >>it was on a 727.
> >>
> >I seem to recall it being on the right engine of a DC-9. I wonder what became
> >of that idea.
>
> I remember what may be the same picture, a DC-9 fitted with a high-bypass
> turbofan, and multiple scimitar-shaped fan blades extending from the
> first-stage fan. Damned if I can find it now, though. Nothing like it so
> far on the NASA Dryden site. Any other ideas?

The one thing I can remember about the program was that the suckers were
too loud to fly over most cities in the US.

--
cirby at cfl.rr.com

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

[Thomas Schoene]

George Ruch wrote:

> I remember what may be the same picture, a DC-9 fitted with a
> high-bypass turbofan, and multiple scimitar-shaped fan blades
> extending from the first-stage fan. Damned if I can find it now,
> though. Nothing like it so far on the NASA Dryden site. Any other
> ideas?

They called in an unducted fan or ultra-high bypass turbofan.

Pictures:

http://www.b-domke.de/AviationImages/Rarebird/0809.html

http://www.nurflugel.com/Nurflugel/NASM/Img0052.jpg

--
Tom Schoene Replace "invalid" with "net" to e-mail
"If brave men and women never died, there would be nothing
special about bravery." -- Andy Rooney (attributed)

[The Enlightenment]

"Peter Stickney" > wrote in message
...
> In article >,
> "The Enlightenment" > writes:
> > Those sorts of performances I think were achievable with piston
> > engines.
> >
> > The Luft46 web site lists a few German pusher prop aircraft that
were
> > projected as replacements for then current Lufwaffe aircraft.
> > Achieving as much as 584 mph on an ordinary 1750HP Jumo 213 V12
piston
> > engine seems to have been accepted.
>
> Quite frankly, that's bat****.
> <cue the every 3 months lecture on the Speed/Power relationship for
> the thrust of propeller driven airplanes.>
> To cut to the chase - a constnt power output engine, like a recip,
or
> the propeller side of a turboprop, produces less thrust the faster
you
> go. Assuming 85% propeller efficiency across the board, your 1750
HP
> Jumo is producing 2790# of thrust at 200 mph, 1490# of thrust at 375
> mph, and at 584 mph, 955# of thrust. (It's actually a lot worse than
> that - the efficiency of the prop goes way down beyond about 450-500
> mph at Sea Level.

You make one oversight though it is perhaps mine:

1 There are actualy 2 Jumo 213Js on this aircraft driving coaxial
contra-roting props so this automatically doubles the thrust.
2 I believe the Jumo specification is incorrect. Takeoff power is
1750 but with MW50 water methanol injection to allow overboost it is
someting like 2250hp. Likewise at high altitudes a Nitrous Oxide "Ha
Ha" system can bring power up to about 2150 hp because of the extra
oxgen in the NO and its anti-knock properties. Both systems were
fitted to the TA152

(for some reason I can get onto google but certainly the TA152H Jumo
213 could produce 2250hp I don't know if it was a J though)

Thus without boost an equivalent thrust of 900kg - 2000lbs is
available and that would presumably be maintained to quite a high
altitude where the atmoshere is at least half of sea level density and
probably less. With boost more like 2500lbs.

Incidently Anthony Kays book lists the following thrusts of the Jumo
004B1 jet as used in a Me262.

900kg sea level static
730kg seal level 559 mph (a test chamber result I suspect, German
test chambers were excellent and so good they were used by the allies)
320kg at 10000m



>
> > This scimitar prop aircraft is one of the fastest at 584mph.
> > http://www.luft46.com/dornier/dop252.html
>
> Even assuming that there are _no_ transonic effects on the airframe

It DOES have swept wings and 584mph is not at the high end of
transonic. The AVA at Goetingen (German Equavalent to NACA) did a lot
of supersonic research in the mid 30s.

> (Which there will be), and two engines, the Equivalent Profile Area
of
> the drawing below is 3.55 sq ft. (That's Drag Coefficient *
Reference
> Area).
> A P-51 works out to a profile area of about 4.66 ft.
> This Dornier cattywampus is more that twice the size of a P-51.
> The claims are rediculouss on the face of it. The SS Scientific
Branch
> might believe such horse****, but real life physics wins every time.

A pusher aircraft has less drag becuase there is no high velocity
airflow over the airframe that is turbulent to boot. This on its own
suggests higher speed.

>
> (And the Scientific Branch certainly _did_ believe such horse****.
> They sent a specialist in Infrared Photography to Spitzbergen to
> photograph the British Home Fleet at Scapa Floe through the Hole
into
> the Hollow Earth.)

Sounds like the one where a Jewish doctor cut of Hitlers testicals
that was circulated in the war.

>
> > The advantage would be fuel efficiency and the lack of refractory
> > alloys needed for the engine. The cost of making high octane fuel
is
> > exorbitant compared to make Jet fuel.
>
> > I recall seeing GE tested scimitar shaped pusher prop engines, I
think
> > it was on a 727.
>
> And it wasn't operating at 85% efficency at that Mach Number,
either.
> The thrust numbers I posted above are best case.

85% for a scimitar shapped contra-rotating prop is good but I think
achievable.

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

[Urban Fredriksson]

In article >,
Nev > wrote:

>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?

Do you think the Embraer ALX and Pilatus PC-21 look like a
Piper PA48 Enforcer (only with nose gear and yes - I know
it's not really a Mustang)? If something like 4 x 20 mm is
enough, it seems that configuration works well. If you
want something like a Oerlikon KCA, GAU-8 or even Oerlikon
35/1000 a pusher prop might be indicated.
--
Urban Fredriksson http://www.canit.se/%7Egriffon/
A king and an elephant were sitting in a bathtub. The king said, "pass
the soap" and the elephant said, "No soap, radio!"

[robert arndt]

George Ruch > wrote in message >...
> (Nev) wrote:
>
> >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?
>
> [snip]
>
> >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?
>
> Uh, it WAS a modernized Mustang- the Piper Pa-48 Enforcer of the '80s:

http://www.aerofiles.com/piper-pa48.jpg

.... and rejected too...

Rob

[David McArthur]

(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?
>
> 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?

About 15 yrs ago BAe messed around with a project called SABA ('small
agile battlefield aicraft') one of the designs touted was a v.
lightweight pusher UDF propellor craft with about a 2 ton warload.
Looked pretty cool. I think it was mainly an anti-tank craft designed
to fill the void between attack helicopters and full-blown ground
attack aircraft.

David

[Scott Ferrin]

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 :-)

[Tarver Engineering]

"Thomas Schoene" > wrote in message
link.net...
> George Ruch wrote:
>
> > I remember what may be the same picture, a DC-9 fitted with a
> > high-bypass turbofan, and multiple scimitar-shaped fan blades
> > extending from the first-stage fan. Damned if I can find it now,
> > though. Nothing like it so far on the NASA Dryden site. Any other
> > ideas?
>
> They called in an unducted fan or ultra-high bypass turbofan.
>
> Pictures:
>
> http://www.b-domke.de/AviationImages/Rarebird/0809.html
>
> http://www.nurflugel.com/Nurflugel/NASM/Img0052.jpg

Russian prop benders were on site for the program. The engine saves about
23% of fuel compared to regular high bypass engines, of the time. (pre
tripple spool compressor)

[Greg Hennessy]

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.

[Ad absurdum per aspera]

> >I recall seeing GE tested scimitar shaped pusher prop engines, I think
> >it was on a 727.

> I seem to recall it being on the right engine of a DC-9. I wonder what became
> of that idea.


"Unducted fans" or "propfans" were, I believe, tested on both a 727
and an MD-80. See for instance

http://www.jsc.nasa.gov/er/seh/profan.html (contemporary article from
midway through the program)


http://www.aerospaceweb.org/question/propulsion/q0067.shtml (survey
article; pix)


http://www.aviation-history.com/garber/vg-bldg/udf-2_f.html


The goals were, I think, a combination of fuel efficiency and some
internal simplifications.


I'm not exactly sure why they aren't much in use. Hypotheses I've
read include greater risk to the passenger cabin from uncontained
failures (I wonder if it is coincidence that both the testbeds were
the sort of jets with aft-mounted engines); undesirable "propeller"
image; noise; and parallel improvements in high-bypass turbofans of
the usual ducted design.

Cheers,
--Joe

[Ron]

>About 15 yrs ago BAe messed around with a project called SABA ('small
>agile battlefield aicraft') one of the designs touted was a v.
>lightweight pusher UDF propellor craft with about a 2 ton warload.
>Looked pretty cool. I think it was mainly an anti-tank craft designed
>to fill the void between attack helicopters and full-blown ground
>attack aircraft.
>
>David

Sounds a lot like the Rutan ARES.


Ron
Pilot/Wildland Firefighter

[The Enlightenment]

"Ad absurdum per aspera" > wrote in message
om...
> > >I recall seeing GE tested scimitar shaped pusher prop engines, I
think
> > >it was on a 727.
>
> > I seem to recall it being on the right engine of a DC-9. I wonder
what became
> > of that idea.
>
>
> "Unducted fans" or "propfans" were, I believe, tested on both a 727
> and an MD-80. See for instance
>
> http://www.jsc.nasa.gov/er/seh/profan.html (contemporary article
from
> midway through the program)
>


Thanks for these links. They all seem to think that a Mach 0.85 for a
scimitar blade contra-rotating coaxial "prop-fan" is possible and
indeed fuel efficient. Given that there was in a German 1940s study
suggesting 584 mph with twin piston engines I think its fairly
believable. I find the idea of a Mach 0.85 diesel or spark ignition
engine fascinating.

There is also the Soviet An 70
http://www.geocities.com/CapeCanaveral/9735/antonov1.htm I would be
interesting to read what the Russian desginers thought that they
gained with this designe of a straight jet or prop. I know that a
C-17 got bogged at a Sarajevo airport on a bit of wet grass and that
this lack of grunt is due to the use of jets instead of props.

Either way the Russians are ready to go apparently!

Another fascinating possibility is the use of SOFC (Solid Oxide Fuel
Cells). Many people beleive these will match piston engines in cars
in terms was weight. If turbo supercharged they should have an
amazing efficiency of 85%. They opperate at 800C at which point the
metal oxide membranse can conduct oxygen ions (instead of hysrgen
ions) and thus burn hydrocarbon fuels. The high temperature (still
only 1/3rd that of a pertrol engine) means that no catalyst is needed.
They are running in the lab at 60% efficient unburdened but becuase
they exhaust at 800-1000C they can be trubo-supercharged and excess
shaft power extracted.

These SOFCs should achieve the same power to weigh ratio of petrol
engines and thus be able to propell aircraft. Potentialy their engine
and cell life will be so high that they compete with gas trubines.
They would require only modes cooling and would require light
propellors since no piston torgue vibarations would be present.



> I'm not exactly sure why they aren't much in use. Hypotheses I've
> read include greater risk to the passenger cabin from uncontained
> failures (I wonder if it is coincidence that both the testbeds were
> the sort of jets with aft-mounted engines); undesirable "propeller"
> image; noise; and parallel improvements in high-bypass turbofans of
> the usual ducted design.
>
> Cheers,
> --Joe

I think there were some noise issues (not major), blade safety I
think could be handled (the scimitar shaped much add unusual
stresses), then there is the issue of gear boxes. These are high
maintain items. (The only geared turbo fan in sevice is that unit
(Allison) on the BAE avro regional/ BAE146 series jet I think)

It will be interesting to see if Pratt+Whitney's PW8000 geared
turbofan for airbus changes the anti-gearbox mindset.









>
> http://www.aerospaceweb.org/question/propulsion/q0067.shtml (survey
> article; pix)
>
>
> http://www.aviation-history.com/garber/vg-bldg/udf-2_f.html
>
>
> The goals were, I think, a combination of fuel efficiency and some
> internal simplifications.
>
>

[Mary Shafer]

On Wed, 03 Dec 2003 23:11:57 -0700, George Ruch
> wrote:

> I remember what may be the same picture, a DC-9 fitted with a high-bypass
> turbofan, and multiple scimitar-shaped fan blades extending from the
> first-stage fan. Damned if I can find it now, though. Nothing like it so
> far on the NASA Dryden site. Any other ideas?

We put ours on the spine of the Jetstar and drove it with bleed air.

That DC-9 you recall probably belonged to GE, which has a test
facility in Mojave.

Mary

--
Mary Shafer Retired aerospace research engineer

[George Ruch]

Chad Irby > wrote:

>In article >,
> George Ruch > wrote:
>
>> (B2431) wrote:
>>
>> >>From: "The Enlightenment"
>> >>
>> ><snip>
>> >>
>> >>I recall seeing GE tested scimitar shaped pusher prop engines

[snip]

>> I remember what may be the same picture, a DC-9 fitted with a high-bypass
>> turbofan, and multiple scimitar-shaped fan blades extending from the
>> first-stage fan. Damned if I can find it now, though. Nothing like it so
>> far on the NASA Dryden site. Any other ideas?
>
>The one thing I can remember about the program was that the suckers were
>too loud to fly over most cities in the US.

Probably so. Something like flying next to a TU-95 (migraine headache
number 43, or so I've heard).

/------------------------------------------------------------\
| George Ruch |
| "Is there life in Clovis after Clovis Man?" |
\------------------------------------------------------------/

[George Ruch]

"Thomas Schoene" > wrote:

>George Ruch wrote:
>
[snip]

>They called in an unducted fan or ultra-high bypass turbofan.
>
>Pictures:
>
>http://www.b-domke.de/AviationImages/Rarebird/0809.html
>
>http://www.nurflugel.com/Nurflugel/NASM/Img0052.jpg

So much for memory <g> Right idea, wrong end of the engine.

/------------------------------------------------------------\
| George Ruch |
| "Is there life in Clovis after Clovis Man?" |
\------------------------------------------------------------/

[Tarver Engineering]

"Mary Shafer" > wrote in message
...
> On Wed, 03 Dec 2003 23:11:57 -0700, George Ruch
> > wrote:
>
> > I remember what may be the same picture, a DC-9 fitted with a
high-bypass
> > turbofan, and multiple scimitar-shaped fan blades extending from the
> > first-stage fan. Damned if I can find it now, though. Nothing like it
so
> > far on the NASA Dryden site. Any other ideas?
>
> We put ours on the spine of the Jetstar and drove it with bleed air.
>
> That DC-9 you recall probably belonged to GE, which has a test
> facility in Mojave.

GE red hats from North Base did the UDF and the GE90. IIRC there is only an
artist's rendering of the UDF on an MD-80, while the engine actually flew on
the flight test 727-100 that lives at Mojave.

[Steve Hix]

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?

[Mary Shafer]

On Thu, 4 Dec 2003 18:11:14 -0800, "Tarver Engineering"
> wrote:

>
> "Mary Shafer" > wrote in message
> ...
> > On Wed, 03 Dec 2003 23:11:57 -0700, George Ruch
> > > wrote:
> >
> > > I remember what may be the same picture, a DC-9 fitted with a
> high-bypass
> > > turbofan, and multiple scimitar-shaped fan blades extending from the
> > > first-stage fan. Damned if I can find it now, though. Nothing like it
> so
> > > far on the NASA Dryden site. Any other ideas?
> >
> > We put ours on the spine of the Jetstar and drove it with bleed air.
> >
> > That DC-9 you recall probably belonged to GE, which has a test
> > facility in Mojave.
>
> GE red hats from North Base did the UDF and the GE90. IIRC there is only an
> artist's rendering of the UDF on an MD-80, while the engine actually flew on
> the flight test 727-100 that lives at Mojave.

You're right. I was thinking, as I wrote "DC-9", that something
wasn't right about that, but I couldn't quite remember what. It was a
727, not a DC-9, is what.

Photos of it, with the odd engine, would show up now and then as a
"look at that" item in the various aviation magazines. There was at
least one in "Straight and Level".

Mary


--
Mary Shafer Retired aerospace research engineer

[Tarver Engineering]

"Mary Shafer" > wrote in message
...
> On Thu, 4 Dec 2003 18:11:14 -0800, "Tarver Engineering"
> > wrote:
>
> >
> > "Mary Shafer" > wrote in message
> > ...
> > > On Wed, 03 Dec 2003 23:11:57 -0700, George Ruch
> > > > wrote:
> > >
> > > > I remember what may be the same picture, a DC-9 fitted with a
high-bypass
> > > > turbofan, and multiple scimitar-shaped fan blades extending from the
> > > > first-stage fan. Damned if I can find it now, though. Nothing like
it so
> > > > far on the NASA Dryden site. Any other ideas?
> > >
> > > We put ours on the spine of the Jetstar and drove it with bleed air.
> > >
> > > That DC-9 you recall probably belonged to GE, which has a test
> > > facility in Mojave.
> >
> > GE red hats from North Base did the UDF and the GE90. IIRC there is
only an
> > artist's rendering of the UDF on an MD-80, while the engine actually
flew on
> > the flight test 727-100 that lives at Mojave.
>
> You're right. I was thinking, as I wrote "DC-9", that something
> wasn't right about that, but I couldn't quite remember what. It was a
> 727, not a DC-9, is what.

In '97 when i was contracting at Boeing Everett there was a manager with the
MD-80 artist's rendition on the wall and i mentioned that the engine had at
least flown on a 727.

> Photos of it, with the odd engine, would show up now and then as a
> "look at that" item in the various aviation magazines. There was at
> least one in "Straight and Level".

The funny part is that the flying MD-80 artist's rendition is used fairly
commonly to show the engine, even though it never happened.

[Tom Mosher]

Mary Shafer > wrote in message >...
> On Thu, 4 Dec 2003 18:11:14 -0800, "Tarver Engineering"
> > wrote:
>
> >
> > "Mary Shafer" > wrote in message
> > ...
> > > On Wed, 03 Dec 2003 23:11:57 -0700, George Ruch
> > > > wrote:
> > >
> > > > I remember what may be the same picture, a DC-9 fitted with a
> high-bypass
> > > > turbofan, and multiple scimitar-shaped fan blades extending from the
> > > > first-stage fan. Damned if I can find it now, though. Nothing like it
> so
> > > > far on the NASA Dryden site. Any other ideas?
> > >
> > > We put ours on the spine of the Jetstar and drove it with bleed air.
> > >
> > > That DC-9 you recall probably belonged to GE, which has a test
> > > facility in Mojave.
> >
> > GE red hats from North Base did the UDF and the GE90. IIRC there is only an
> > artist's rendering of the UDF on an MD-80, while the engine actually flew on
> > the flight test 727-100 that lives at Mojave.
>
> You're right. I was thinking, as I wrote "DC-9", that something
> wasn't right about that, but I couldn't quite remember what. It was a
> 727, not a DC-9, is what.
>
> Photos of it, with the odd engine, would show up now and then as a
> "look at that" item in the various aviation magazines. There was at
> least one in "Straight and Level".
>
> Mary

The UDF on an MD-80 flew. They even took it to Farnborough in 1988.

http://www.airliners.net/open.file/212668/M/
http://www.airliners.net/open.file/340963/M/


Tom Mosher

[Tarver Engineering]

"Tom Mosher" > wrote in message
om...
> Mary Shafer > wrote in message
>...
> > On Thu, 4 Dec 2003 18:11:14 -0800, "Tarver Engineering"
> > > wrote:
> >
> > >
> > > "Mary Shafer" > wrote in message
> > > ...
> > > > On Wed, 03 Dec 2003 23:11:57 -0700, George Ruch
> > > > > wrote:
> > > >
> > > > > I remember what may be the same picture, a DC-9 fitted with a
> > high-bypass
> > > > > turbofan, and multiple scimitar-shaped fan blades extending from
the
> > > > > first-stage fan. Damned if I can find it now, though. Nothing
like it
> > so
> > > > > far on the NASA Dryden site. Any other ideas?
> > > >
> > > > We put ours on the spine of the Jetstar and drove it with bleed air.
> > > >
> > > > That DC-9 you recall probably belonged to GE, which has a test
> > > > facility in Mojave.
> > >
> > > GE red hats from North Base did the UDF and the GE90. IIRC there is
only an
> > > artist's rendering of the UDF on an MD-80, while the engine actually
flew on
> > > the flight test 727-100 that lives at Mojave.
> >
> > You're right. I was thinking, as I wrote "DC-9", that something
> > wasn't right about that, but I couldn't quite remember what. It was a
> > 727, not a DC-9, is what.
> >
> > Photos of it, with the odd engine, would show up now and then as a
> > "look at that" item in the various aviation magazines. There was at
> > least one in "Straight and Level".
> >
> > Mary
>
> The UDF on an MD-80 flew. They even took it to Farnborough in 1988.
>
> http://www.airliners.net/open.file/212668/M/
> http://www.airliners.net/open.file/340963/M/

That's really cute, but not the one in the picture we are discussing.

"Tarver Engineering" > wrote in message
...
>
> "Tom Mosher" > wrote in message
> om...
> > Mary Shafer > wrote in message
> >...
> > > On Thu, 4 Dec 2003 18:11:14 -0800, "Tarver Engineering"
> > > > wrote:
> > >
> > > >
> > > > "Mary Shafer" > wrote in message
> > > > ...
> > > > > On Wed, 03 Dec 2003 23:11:57 -0700, George Ruch
> > > > > > wrote:
> > > > >
> > > > > > I remember what may be the same picture, a DC-9 fitted with a
> > > high-bypass
> > > > > > turbofan, and multiple scimitar-shaped fan blades extending from
> the
> > > > > > first-stage fan. Damned if I can find it now, though. Nothing
> like it
> > > so
> > > > > > far on the NASA Dryden site. Any other ideas?
> > > > >
> > > > > We put ours on the spine of the Jetstar and drove it with bleed
air.
> > > > >
> > > > > That DC-9 you recall probably belonged to GE, which has a test
> > > > > facility in Mojave.
> > > >
> > > > GE red hats from North Base did the UDF and the GE90. IIRC there is
> only an
> > > > artist's rendering of the UDF on an MD-80, while the engine actually
> flew on
> > > > the flight test 727-100 that lives at Mojave.
> > >
> > > You're right. I was thinking, as I wrote "DC-9", that something
> > > wasn't right about that, but I couldn't quite remember what. It was a
> > > 727, not a DC-9, is what.
> > >
> > > Photos of it, with the odd engine, would show up now and then as a
> > > "look at that" item in the various aviation magazines. There was at
> > > least one in "Straight and Level".
> > >
> > > Mary
> >
> > The UDF on an MD-80 flew. They even took it to Farnborough in 1988.
> >
> > http://www.airliners.net/open.file/212668/M/
> > http://www.airliners.net/open.file/340963/M/
>
> That's really cute, but not the one in the picture we are discussing.
>
>
How about this ugly thing mounted on what appears to be the wing of a DC-9
(upper right image in the group of three).

http://www.aerospaceweb.org/question/propulsion/q0067.shtml

[Tarver Engineering]

> wrote in message
y.com...
> >
> How about this ugly thing mounted on what appears to be the wing of a DC-9
> (upper right image in the group of three).
>
> http://www.aerospaceweb.org/question/propulsion/q0067.shtml

It's not as pretty as the one in the picture in question. Although the DC-9
would have provided a much more likely vehicle for production. The UDF was
tested back when Pratt was sucking gas, but things have changed since then.