WWII warplanes vs combat sim realism

On Sat, 22 Nov 2003 21:14:48 +0200, "Jukka O. Kauppinen"
wrote:

The real problem was the center of gravity behind the undercarriage.
This made it possible to brake unusually hard in landings, but it also
required the pilot to keep the plane straight in takeoff and landing. If
this failed the plane could get into quickly worsening turn until the
other undercarriage failed or the plane drifted off the runway.

Generally, this was very interesting reading.

If I may make a few comments though....

The Cg was only part of the problem with the 109s ground instability, it was the
extreme negative camber of the wheels, combined with a "toe-out" condition that
induced the much of the instability. Compare with the Spitfire, positive camber
and a few degrees of "toe-in" produced far more stable ground handling on a
narrower track. Grumman used similar geometry for the G-36/F4F.


I'm putting together an article about various aspects of the 109 with
pilot commentary. Here's some quotes about 109s diving:

- The Me 109 was dived to Mach 0.79 in instrumented tests. Slightly
modified, it was even dived to Mach 0.80, and the problems experimented
there weren't due to compressility, but due to aileron overbalancing.
Compare this to Supermarine Spitfire, which achieved dive speeds well
above those of any other WW2 fighter, getting to Mach 0.89 on one
occasion. P-51 and Fw 190 achieved about Mach 0.80. The P-47 had the
lowest permissible Mach number of these aircraft. Test pilot Eric Brown
observed it became uncontrollable at Mach 0.73, and "analysis showed
that a dive to M=0.74 would almost certainly be a 'graveyard dive'."
- Source: Radinger/Otto/Schick: "Messerschmitt Me 109", volumes 1 and 2,
Eric Brown: "Testing for Combat".

Which model of the P-47 was Eric Brown describing? With the introduction of the
P-47D-30, dive recovery flaps were standard, and dive speeds up Mach 0.83 became
uneventful. I have plenty of test data to support that. I have placed one data
sheet on the web at: http://home.att.net/~Historyzone/DiveChart.html

Here we see the P-47 diving at Mach 0.79, in just one of 300 dive tests that
varied from Mach 0.76 through Mach .083 over the course of several months.
Curtiss Wright test pilot Herb Fisher flew the test for the purpose of
evaluating various propeller blade designs at high sub-sonic Mach
where most of the blade was in the transonic region.


"My flight chased 12 109s south of Vienna. They climbed and we followed,
unable to close on them. At 38,000 feet I fired a long burst at one of
them from at least a 1000 yards, and saw some strikes. It rolled over
and dived and I followed but soon reached compressibility with severe
buffeting of the tail and loss of elevator control. I slowed my plane
and regained control, but the 109 got away.
On two other occasions ME 109s got away from me because the P 51d could
not stay with them in a high-speed dive. At 525-550 mph the plane would
start to porpoise uncontrollably and had to be slowed to regain control.
The P 51 was redlined at 505 mph, meaning that this speed should not be
exceeded. But when chasing 109s or 190s in a dive from 25-26,000 it
often was exceeded, if you wanted to keep up with those enemy planes.
The P 51b, and c, could stay with those planes in a dive. The P 51d had
a thicker wing and a bubble canopy which changed the airflow and brought
on compressibility at lower speeds."
- Robert C.Curtis, American P-51 pilot.

I wouldn't put too much stock in the Curtis quote.

If I remember correctly, Curtis transitioned from the P-38J into the P-51D.
I imagine that he had a few frightening experiences diving the P-38. Why,
because if he is accurately quoted, he seems a bit reluctant to push the Mustang
as you can be absolutely sure that the Bf 109 was into compressibility as well.
Much of the information in his quote is incorrect. There was no increase in wing
thickness and his redline speed for the P-51 is for much lower altitude
operation, not at 38,000 feet. How about an example attributed to Sid Woods, who
tested the P-51at Wright Field and later took into combat and finished the war
with more than 10 victories?

"In contrast, the P-51, had far fewer compressibility problems at speeds
normally encountered in combat, including dives from high altitude. The D
model was placarded at 300 mph IAS (539 mph TAS, Mach 0.81) at 35,000 ft.
In a dive, the P-51 was such an aerodynamically clean design that it could
quickly enter compressibility if the dive was continued (in reality, a
pilot could, as a rule, catch any German plane before compressibility
became a problem). But, say, in an evasive dive to escape, as the P-51's
speed in the dive increased, it started skidding beyond what the pilot
could control (this could be a problem in a dive onto a much lower-flying
plane or ground target--couldn't keep the plane tracking on the target if
speed was too high). As compressibility was entered, it would start
rolling and pitching and the whole plane would begin to vibrate. This
began about Mach 0.72. The pilot could maintain control to above Mach
0.80 (stateside tests said 0.83 (605 mph) was max safe speed--but
structural damage to the aircraft would result)."

Curtis' assertion that the bubble canopy induced compressibility at lower
speeds is bunk. Direction instability at high speeds was a problem through the
P-51D-5-NA. Later models were fitted with a "dorsal fin" which largely cured the
instability. All earlier D models were retro-fitted in the field as kits became
available (they also received a modification to the rudder trim tab).

Thanks for a very interesting read.

My regards,

Widewing (C.C. Jordan)
http://www.worldwar2aviation.com
http://www.cradleofaviation.org

"Jukka O. Kauppinen" wrote in
:

decides the fight! Alas for the luftwaffe the Bf109 wings were not
designed for guns etc so were not terrifically robust, the pilots
were often more worried about the wings falling off than blacking
out......

Incorrect.

Having guns or not doesn't have anything to do with the strenght of
the wings. 109s from A-E had wing weapons, again one of the K models
was designed for wing weapons. The wings were also one single
structure, which made it possible to make them very strong.

"- Are the stories true, that the 109 had weak wings and would loose
them easily?
He has never heard of a 109 loosing its wings from his experience or
others. The wings could withstand 12 g's and since most pilots could
only handle at most 9 g's there was never a problem. He was never
worried about loosing a wing in any form of combat."
- Franz Stigler, German fighter ace. 28 victories. Interview of Franz
Stigler.

"The maximum speed not to be exceeded was 750kmh. Once I was flying
above Helsinki as I received a report of Russkies in the South. There
was a big Cumulus cloud on my way there but I decided to fly right
through. I centered the controls and then something extraordinary
happened. I must have involuntarily entered into half-roll and dive.
The planes had individual handling characteristics; even though I held
the turning indicator in the middle, the plane kept going faster and
faster, I pulled the stick, yet the plane went into an ever steeper
dive. In the same time she started rotating, and I came out of the
cloud with less than one kilometer of altitude. I started pulling the
stick, nothing happened, I checked the speed, it was about 850kmh. I
tried to recover the plane but the stick was as if locked and nothing
happened. I broke into a sweat of agony: now I am going into the sea
and cannot help it. I pulled with both hands, groaning and by and by
she started recovering, she recovered more, I pulled and pulled, but
the surface of the sea approached, I thought I was going to crash. I
kept pulling until I saw that I had survived. The distance between me
and the sea may have been five meters. I pulled up and found myself on
the coast of Estonia. If I in that situation had used the vertical
trim the wings would have been broken off. A minimal trim movement has
a strong effect on wings when the speed limit has been exceded. I had
100kmh overspeed! It was out of all limits.
The Messerschmitt's wings were fastened with two bolts. When I saw the
construction I had thought that they are strong enough but in this
case I was thinking, when are they going to break
- What about the phenomenon called "buffeting" or vibration, was there
any? No, I did not encounter it even in the 850kmh speed."
- Kyösti Karhila, Finnish fighter ace. 32 victories. Source: Interview
by Finnish Virtual Pilots Association.

Given that 109s were routinely dived at 800-900 km/hour speeds that
certainly shows that if there was some weaknesses in the plane, wings
werent' them.

jok


Sorry mate, the wings on a Bf109 were NOT one piece. The wings were
attached to the fuselage at the wing root just outboard of the u/c and it
was possible to remove the mainplanes and leave the aircraft still standing
on its u/c (which was actually attached to fuselage). This very narrow
track u/c was one of the weak points of the design and when Tank designed
the FW190 he deliberately went the other way and designed his aircraft with
a one piece wing with wery wide track u/c.

On Sat, 22 Nov 2003 17:26:09 +0000, Greg Hennessy
wrote:

What we
really need is a new type with 30-40 years of operational life at a
shatteringly low pound sterling per bomb cost, rather than trying to
reanimate an old V Force zombie which guzzles fuel using late '50's
engine technology.

True.

Allow me to clarify a little: we _are_ trying to reanimate an old
V-Force zombie, just one that doesn't guzzle fuel using late '50's
engine technology and otherwise keeps operating costs relatively low.

Ahh we wouldn't be good europeans then mate :-).

Nobody else is pushing a similar requirement, although I'm sure the
French will jump on the bandwagon to "collaborate" (**** it up)
if they thought it might actually have a danger of appearing. We can
call it RAF A.L. to annoy them.

PMPL!

Right, "RAF Advanced Lifting-body" it is then.

/me shudders at the thoughts of Nimrod AEW.

Yeah, but that was the internal squiggly bits fit. This project is an
existing-tech come as you are party. No new mission-critical systems
to be built from scratch and which can fail the airframe and the whole
project.

As with the Aden-25, it never ever works out that way though. It would turn
into another 'how can we featherbed Bae' project.

Sure, but we're acknowledging that upfront. Where we score over
Eurobanker, sorry, Typhoon, is that there is one primary contractor,
one service and one procurement machine involved. Inefficient still?
Hell, yes, but better than collaborating with the French. And the
design is specifically _not_ state-of-the-art. All we want, afterall,
is a subsonic jetliner with a large bombload and massive internal fuel
capacity. The only performance figures we care about are range,
endurance, bombload and a fast economic cruise speed. And low
operating costs.

This is what we want. Sod the radar signature, if the opposition have
any credible ability to a) detect it tooling in for the bomb run at
46,000 feet or b) intercept a nice, fat target like it,

A lifting body design could be surprisingly stealthy I reckon. All that
volume gives plenty of space to hide 3-4 RR Trents internally.

Now we're on to something. What can we get out of four Trents in
terms of airframe weight, payload* and range?

[*Including token human aircrew in order to get the Air Marshalls to
buy in to the project]

it won't be
going anywhere until the defences are suppressed. Afterwards they
orbit Talibanistan with their humungous internal fuel capacity at 0.9
Mach all day long dropping PGMs on every mud hut until they run out of
stores and go home.

LOL!

But this is what the RAF actually will *need*: maximum efficiency for
the missions they will carry out, and bugger (to some extent) the
capability to do the flasher, harder stuff.

I want a 10,000 mile range on internal fuel with a minimum of 50,000
lbs internal bombload, lowest quote wins.

Why only 50k pounds ? A lifting body could easily carry 2-3 times that
without becoming overly large. I am sure the thoughts of them orbiting at
45k feet with 500 SDBs on board would give any corps commander a wet dream.

Precisely. Let's go for 50 x 2,000lb LGB's (or 100 x 1,000lb LGB's)
internal capacity as a starting point.

Gavin Bailey

--

"Will Boogie Down For Food".- Sign held by Disco Stu outside the unemployment office.

On Mon, 24 Nov 2003 10:00:14 GMT, (The Revolution
Will Not Be Televised) wrote:


True.

Allow me to clarify a little: we _are_ trying to reanimate an old
V-Force zombie, just one that doesn't guzzle fuel using late '50's
engine technology and otherwise keeps operating costs relatively low.


Off the shelf is where its at.


As with the Aden-25, it never ever works out that way though. It would turn
into another 'how can we featherbed Bae' project.

Sure, but we're acknowledging that upfront. Where we score over
Eurobanker, sorry, Typhoon, is that there is one primary contractor,
one service and one procurement machine involved.

Yes, I can see where that would be an advantage. Rather than lets see how
we can copy the An-70.

Inefficient still?
Hell, yes, but better than collaborating with the French.

Anything is better than that. The fate of the Jaguar-M should have made it
plain w.r.t the French being in it for anyone other than themselves.

And the
design is specifically _not_ state-of-the-art. All we want, afterall,
is a subsonic jetliner with a large bombload and massive internal fuel
capacity. The only performance figures we care about are range,
endurance, bombload and a fast economic cruise speed. And low
operating costs.

I wouldn't have thought it that hard to do either given that its been done
b4 for commercial aviation.



A lifting body design could be surprisingly stealthy I reckon. All that
volume gives plenty of space to hide 3-4 RR Trents internally.

Now we're on to something. What can we get out of four Trents in
terms of airframe weight, payload* and range?

Two Trents can carry a fully loaded A330 or 777 out to 6-7000 miles with a
take off weight 250 tonnes.


Why only 50k pounds ? A lifting body could easily carry 2-3 times that
without becoming overly large. I am sure the thoughts of them orbiting at
45k feet with 500 SDBs on board would give any corps commander a wet dream.

Precisely. Let's go for 50 x 2,000lb LGB's (or 100 x 1,000lb LGB's)
internal capacity as a starting point.


Lifting body is looking like a shoe-in in that case.


greg

--
$ReplyAddress =~ s#\@.*$##; # Delete everything after the '@'
The Following is a true story.....
Only the names have been changed to protect the guilty.

On Tue, 25 Nov 2003 01:15:13 -0500, (Peter Stickney)
wrote:



Those numbers are the maximum offload. If the tanker flies further,
it can tranfer less fuel. Fir example, a KC-135A would typically
transfer 120,000# at 1150 miles from takeoff, and 24,000# at 3450
miles.

It sounds like the victor had all if not more operating expense than a
kc-135/707 tanker while having less than half the fuel offoad.


I wonder if that particular conversion is what fooled the Air Ministry
into thinking that the Spey=engined Phantoms would be a piece of cake.


That wouldnt surprise me. IMHO someone should have served time for the
whole tsr2/f111K/f4K debacle. The russians must have been laughing their
arses off.




greg
--
$ReplyAddress =~ s#\@.*$##; # Delete everything after the '@'
The Following is a true story.....
Only the names have been changed to protect the guilty.

"The Revolution Will Not Be Televised" wrote in
message ...
On Fri, 21 Nov 2003 18:38:24 +0000, Greg Hennessy
wrote:


Dig those old Short Sperrin airframes out of storage now!

What did happen to the Sperrin airframes? Did they get scrapped in the
1960's (as I suspect)?

Nick

Greg Hennessy wrote in message . ..
On Tue, 25 Nov 2003 01:15:13 -0500, (Peter Stickney)
wrote:



Those numbers are the maximum offload. If the tanker flies further,
it can tranfer less fuel. Fir example, a KC-135A would typically
transfer 120,000# at 1150 miles from takeoff, and 24,000# at 3450
miles.

It sounds like the victor had all if not more operating expense than a
kc-135/707 tanker while having less than half the fuel offoad.

Well... It's a matter of context, really. The KC-135 is a dedicated
Tanker/Transport design, intended to (among other things) top off what
at that time was the world's largest strategic bomber so that it could
go paste any point in the Former Soviet Union and get back home.)
The Valiant/Victor tankers were converted bombers that weren't doing
much else, at the time. A closer U.S parallel would be the KB-50 -
retired bombers used by the Tactical Air Command, USAFE, and PACAF
to support deployments. They weren't optimum for the job, but they'd
already been paid for, and since nobody else wanted them, they wern't
going to be diverted when they were needed.

The KC-135 was a result of lessons learned by Boeing and the AIr Force
about
the amounts of transfer fuel required, and the tanker performance
necessary
to refuel efficiently. While the B-47/KC-97 combination was workable,
refuelling was a knife-edged proposition - the tanker's and receiver's
performance only overlapped in a fairly narrow band. We also had a
secondary requirement to be able to haul stuff along for worldwide
deployments - these were the days of Composite Air Strike Forces -
Reinforced Tactical Fighter Wings that could go anywhere and be
productive on arrival. (Well, that was the theory, anyway.)

The Brit requirements were a bit less stringent - the V-Force could
reach
most of its targets without refuelling, and tey needed to suport the
occaisional Long Range Fighter Command deployment from, say, Suffolk
to Scotland. (I love Brit jets, but I'd really like to see one
where you
don't have to declare a fuel emergency just after pulling the gear up)

Of course, unsuspected circumstances do arise, which have to be dealt
with,
such as the need to use the entire Victor Tanker force to get one
Vulcan
from Ascention Island to Port Stanley and back.

I wonder if that particular conversion is what fooled the Air Ministry
into thinking that the Spey=engined Phantoms would be a piece of cake.


That wouldnt surprise me. IMHO someone should have served time for the
whole tsr2/f111K/f4K debacle. The russians must have been laughing their
arses off.

Add the French, as well. Dassault was probably Sore Afraid that
Fairey
would build a fighter version of the FD.2 and cut them right out of
the
small Mach 2 fighter business. (If you overlay a same-scale image of
the
Mirage III over the FD.2, the resemblance is, shall we say, uncanny.)

It wasn't jusst fighters, or bombers, either. A whole series of
potentially useful and marketable transport aircraft adn airliners
was thrown away without thought.

The handling of the British Aviation Industry by various of Her
Majestey's
Governments in the '50s and '60s is a strange story. Derek Wood's
"Project Cancelled" is bittersweet reading.

--
Pete Stickney
On the road at the moment

wrote in message . ..
Thanks for that Mark. Maybe blackouts should be in the game, but then the
problem lies, not with the aircraft flight models but with the modelling of
the pilots G-force tolerence.
Blackout- a 'naive' pilot will lose vision at about 3 -3 1/2 G. First
time it happened to me I was in Av Cadets doing a loop in a T28 A and
all of a sudden i couldn't see. I was still awake so I eased off on
the stick and I could see again. The loop went to hell. Now for anti-G
- in WW2 the USAAF devised the 'M1 maneuver.' Anyone can do it - just
takes a little practice, You tighten up all the muscles south of the
diaphragm (You need that for breathing - G) Exactly as in the
isometric type exercises. Lower gut, thighs (quads and hams) calves
and feet. The idea is to use your muscles as a G-suit. It works well,
in fact, as good as a pneunmatic G suit. it just wears you out pretty
quick. And in serious trouble (nose buried, running out of sky, or you
trapped a bad guy at six) the adrenalin will help you squeeze even
harder. Now hear this - a pilot in the right frame of mind and skilled
at the M1 maneuver can pull the wings off his airplane and stay awake
doing it. Such a pilot can sustain about 7 G until he gets tired of it
- which won't take too long. Since G-tolerance is very idiosyncratic -
varying widely between individuals - I'd say maybe 9G for 10-15
seconds is a pretty good limit. Some guys have done much better. As
for pulling the wings off - 12-13G from a stick yank would do it in
very quickly if and only if the aircraft has a few years of hard use
on it. ( I know of an F4 that went in with about 8 g on it - lost an
entire outer wing. Too many trips to the well. A good friend and his
student went in with it.) If the plane is newish it'll bend the wings
and pop rivets. (We are talking about fighters - a Beech Bonanza would
be long gone by now - as quite a few pilots have already found out.)
Like I used to tell my students - the published G limits are for new
aircraft - don't bet on them - but if you need G to stay alive use as
much as you need.
Walt BJ