Re: He-100 Part II- He P.1079 vs Me 509


"Eunometic" <eunometic@xxxxxxxxxxxx> wrote in message
news:1157493473.988264.137230@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Keith Willshaw wrote:
"Eunometic" <eunometic@xxxxxxxxxxxx> wrote in message
news:1157378069.211424.60250@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Kyle Boatright wrote:


The Tsunami is credited with unofficial speeds of 530mph and 557 on
occaision.


Unofficial = unproven

But plausible, given the difficulties associated with obtaining
independently verified tests.



The Heinkel P.1076 probably had at least 20% more power than the Ta
152H-1.

Unlikely given it was supposed to use the same
Junkers Jumo 213E engine

No. The 546mph speed of the P.1076 is associated with the use of the
Daimler Benz DB603N or the Jumo 213J both of which were to be
considerably more powerfull than the Jumo 213E-1. Both engines were
only in the test bench stage.

The Junkers Jumo 213E engine was only one of the the engines the P.1076
was to take. The German V12 engines shared the same mounting points
"platform" is you prefer. The Junkers Jumo 213E-1 was the engine used
in the Ta 152H and was a version of the Jumo 213E optimised to run of
B4 (91 octane) fuel when it was feared that the manufacture of aromatic
components for blending was under threat.

The Jumo 213S and J were versions witch incorporated 4 valve heads
instead of 3 valve heads. They could also opperate at higher RPM.
They were in testing at the end of the war. The Jumo 213S was even
mote powerfull than the 213J

While the Jumo 213 and Griffon were both about 35L the DB603 was 42L
(but despite bieng of higher swept volume I believe smaller and ligher
than either).



and the Ta 152H-1 had a speed of 472mph.

At 40,000 ft when boosted with nitrous oxide

The Supermarine
Spifetfull was even faster effectively 500mph with about the same power
as the Ta 152.


No the Spiteful had the Griffon 101 which had 25% more power

Not quite 25% more like 17% and possibly 13% less at high altitude.
What confuses the issue is the various types of power boosting and
emergency rating used by German engines.

The Grifffon 101 produced 2420hp probably using 100/130 or perhaps
115/145. The two stage three speed supercharger Junkers Jumo 213E-1
produced 2060hp at takeoff (pretty good for 91 octane fuel with MW50).
That's a 17% difference. Incidently the earlier Jumo 213A-1 which
had only a single stage two speed supercharger could produce more power
but only at lower altitudes: 2240hp when running C3 injection plus
high pressure Water Methanol injection. You will note in my analysis
above I incorrectly used the higher special emergency power of the Jumo
213A-1 of the Fw 190D-9 (2100hp or 2240hp depending on variant of MW50
used) rather than the power of the Jumo 213E-1 (2060) This actually
favours my estimate.

However in both cases of the Griffon and Jumo we have the data for the
takeoff power not the power at altitude. The Jumo 213E would gain at
least 30% by injection of nitrous oxide but only at altitude. The
Junkers Jumo and Griffon would show characteristic zig zag pattern of
power varying with altitude due to gear changes and pressure bleed
while the Daimler Benz engine would deliver power in a smooth fashion
due to the infinetly variable drive.

The DB603N could produce 2700hp takeoff power; 12% more than the
Griffon 101. The Junkers Jumo 213J could also produce at least 2580hp
and it was hoped that this would eventually produce 3000hp. Both
engines were intended to have MW50 and GM-1. Presumably Griffon 101
had some room for growth as well.

So what happens if a 2050hp Jumo 213E-1 is replaced by 2700hp or 2580hp
engine in an aircraft that can do 472mph on the Jumo213E-1?

What happens if the 496mph Spitefulls 2420 hp Griffon is given Nitrous
oxide (a 100kg tank would give 30% more power for 20 minutes) or the
DB603N engine (12% more power and more with NOX). (Incidently the
Germans did replace a 20 series Merlin with a DB605: the Spitfire was
faster)


Well gee given that the Merlin 20 only had a 2 speed single
stage supercharger this aint suprising

What happens of the Coefficient of Drag of is dropped 20%-25%.

What happens of the Mach breakaway where localised supersonic flows
occur is raised by say 0.05M (33mph?)



Handwaving is fun but hardly scientific



The P.1076 however also had a much cleaner airframe, unlike the
'Tsunami' it had no radiator.

Make that 'would have had' none were ever built after all

True, but it was based on the He 100 and wind tunnel testing did occur.


Not a substitute for flight I fear



Its external skin smoothness was like
that of a jet. The P.1076 designers, the Gunter Brothers, were
forward looking engineers noted for their breakthroughs rather than
nostaligic amateurs and enthusiasts: otherwise they would have built
biplanes.

Getting to 500mph on the greater power alone was a done deal, going
well beyond it with a cleaner airframe was also.

Done deal requires FLYING , this aircraft never made it off
the drawing board.

Yet we have piston aircraft flying at 496mph (both Spitefull with
Griffon 101 and Do 335 with the DB603LA 2150hp engine) at the end of
the war.


Indeed - both at the limit of what was possible for a piston
engined fighter.

We have in Germany at least on the test bench engines with 25% to 30%
more power on the way.


As against allied engines IN SERVICE




Perhaps 546mph was
guilding the lilly a bit; the Heinkel sales department was probably
giving estimates for an aircraft with a polished surface and no guns
but a speed well into 500mph is quite realistic. The airframe simply
looks more advance than Tsunami. It also had an 42L engine instead of
a 26L engine and the larger airframe favours wetted area versus power
ratio and frontal area vs power ratio.

Note that the UDF unducted fan concept; essentially just a
contra-rotating propeller, demonstrated cruising speeds of Mach 0.83 as
feasible.


So feasible it was DROPPED.

It had the following advantages
1 Quiter
2 33% less fuel consumption.

It was restricted to aircraft of the DC9 configuration.

Why ?

At the time it
was tested the price of oil was at an all time low ($9-$15 barrel) and
prospects did not seem good plus passengers have grown to fear whirling
propellors of any kind and the UDF it was feared would put them of.
That's how cheap oil was.


Reality check. There were and are plenty of propellor engined
commuter aircraft out there.

The issues were NOISE and performance

The UDF did NOT meet noise requirements for airports
and high bypass turbofans proved good enough





Look at the other competitive unlimited racers. The aircraft are
stripped
of military equipment. The canopies are cut down. The engines are run
at
ridiculous power settings, and are guaranteed to come to a bad end if
the
induction cooling system so much as burps. Again, these are 500 mph
aircraft. Rare Bear, arguably the fastest of these aircraft holds the
FAI
record for speed for a piston engined aircraft. 528 mph, using ~3,800
hp.
A modified mustang (modifications not specified, but the engine was
rated
at
3,000 hp), holds a 15/25 km straight course record at 516 mph.

The Bearcat was never known for its speed or low drag airframe, in
speed it was pretty average. It was a lightwieght fighter known for
its high climb rate and high power to weight ratio. It was designed as
a last ditch interceptor for Kamikazee attacks against low to medium
altitude aircraft. It seems to be a popular airframe for modification.


It was designed to be very fast and have a high climb rate.
To that end they used the smallest slickest airframe that
could hold the engine

Small doesn't mean low drag though.


Feel free to prove the Bearcat has a high drag airframe





Without HUGE horsepower increases, a much smaller airframe, or
tremendous
sacrifices in other performance characteristics, 560 mph isn't
possible
for
a piston engine fighter.

http://www.luft46.com/dornier/dop252.html


Another paper airplane.

What you don't emphasise is that real WW2 fighter were optimised for
opperation at higher altitudes where they couldn't get shredded by
AAA/FLAK.

Tell that the pilots of Hawker Typhoons and P-47's

Typhoons were optimised for low altitude:

Funnny you just claimed no WW2 fighters were so
optimised


Napier was denied funding to
develop high altitude superchargers. P-47's were high altitude
fighters that had a resonable capabillity at low altitude by virtue of
their intercoolers.


Well no , Napier has so m uch trouble getting the basic engine
reliable they were instructed to forget about the supercharger
and build an engine that worked !

Later versions of the Sabre were fitted with in the Tempest VI
and proved very good at all levels. Unfortunately by then
the Meteor was in service and the Vampire was on
the horizon



Reno racers are optimised for entertainment and nostalgia.

Achieving high speeds at high altitude is easier because the lower
airdensity drops drag.


WRONG

1) Piston engine power falls of radically with altitude even with
good supercharger technology


Drag falls of more rapidly so that piston aircraft are faster at higher
altitudes.


Nope, look at the performance curve for the FW-190
the optimum altitude is around 20,000 ft

http://www.spitfireperformance.com/fw190/fw190d9test.html


2) At higher altitudes compressibility becomes a real
problem. The speed of sound is lower in that thin cold
air so aircraft like the Tempest were redlined at below
400 mph above 35,000 ft

Compressabillity can be dealt with or at least limited. It took
engineering science to it.


Indeed but the German manufacturers hadnt solved it in 1945 and
even if they did supersonic props dont work well



Lets do a reality check

The most advanced propeller driven fighter built was the
XF-84H Thundershriek. With the swept wing layout of
the Thunderjet (100 mph FASTER than the Me-262) and
a turboprop power plant that was both more powerful and
lighter than ANY piston engine it had a top speed of 520 mph

It was also massively oversized escort fighter. It had an emergency
malfunction everytime it took off. It was meant to fly at 690mph
(supersonic).


And failed despite all that power and an airframe more advanced
than anything that could be designed in 1945


It's a pity the Supermarine spitfull airframe is not longer airworthy.
One with a hot roded Griffon and would see of a 'Tsunami' no worries.


Given that it was dropped because the new wing was judged
to give no better high speed performance than the standard
wing this seems unlikely.

The Spitefull was much faster than the Spitfire because its laminar
profile wing was not effected by compressabillity anwhere near as much
as the spifires early 1930s technology NACA 4 digit wings.


Psst the Spitfire wing was thin enough to have less compressibility
problems than ANY WW2 fighter

Laminar profile wings were profiled to avoid adverse pressure gradients
since Prandls theory predicted that boundary layer seperation would
occur when the rate of pressure change was less than that rate of
pressure change caused by energy loss due to bondary layer slowing
down.

Like all of the so called 'laminar profiles' it didn't maintain
laminarity but it did deal witgh compressabillity in quite thick wings.


The Spitfire didnt have 'quite thick wings'

Speed was Spitefulls problems: it was handling issues that were in
part caused by abondoning the elliptical planform. Supermarine simply
needed time to debug.


Supermarine disagreed

The new wing was fitted to a modified Spitfire XIV NN660, in order to
make a direct comparison with the earlier elliptical wing, and was
first flown on 30 June 1944 by Jeffrey Quill. Although the new
Spitfire's speed performance was comfortably in excess of an unmodified
Spitfire XIV, the new wing displayed some undesirable behaviour at the
stall which, although not unacceptable, did not come up to the high
standards of Mitchell's earlier elliptical wing.


When you cut and paste its good manners to cite your source

Elliptical wings have the effect of increasing the effect of washout,
indeed they allow more washout to be used. So even though the
efficiency of elliptical wings is insignificantly better than tapered
planforms they seem to improve handling much more.

Doriner Do 335 also initialy had handling problems; these were dealt
with by increasing the wings breadth at the roots to give a mild
Handley Page Victor crescent wing like appearence. The thiner section
then stalled earlier than the tips. Also mildly 'area ruled' the
aircraft.


And its top speed was well under 500 mph

Keith



.

Relevant Pages

  • Re: Papers: Meredith Effect and RR Merlin carburator T.O.
    ... The airframe pulled about the same speed out of the same power as the ... The P-51A did its top speeds at even lower altitudes. ... DB605 engine instead of DB601. ... C3 fuel is nothing like allied 100 octane either early American ...
    (rec.aviation.military)
  • Re: He-100 Part II- He P.1079 vs Me 509
    ... The Tsunami is credited with unofficial speeds of 530mph and 557 on ... Daimler Benz DB603N or the Jumo 213J both of which were to be ... The Junkers Jumo 213E engine was only one of the the engines the P.1076 ... Spifetfull was even faster effectively 500mph with about the same power ...
    (rec.aviation.military)
  • Re: He-100 Part II- He P.1079 vs Me 509
    ... The Tsunami is credited with unofficial speeds of 530mph and 557 on ... Daimler Benz DB603N or the Jumo 213J both of which were to be ... The Junkers Jumo 213E engine was only one of the the engines the P.1076 ... Spifetfull was even faster effectively 500mph with about the same power ...
    (rec.aviation.military)
  • Re: Papers: Meredith Effect and RR Merlin carburator T.O.
    ... By the way the claim the Bf109F was a more efficient airframe than the P-51 ... The airframe pulled about the same speed out of the same power as the ... DB605 engine instead of DB601. ... important than HP ratings when it came to top speeds. ...
    (rec.aviation.military)
  • Re: Do-217P
    ... that altitude, you would need more data on the aircraft, engine and ... Power delivered is Thrust x Velocity (you can look this up virtually in ... a significantly higher altitude. ... Also at higher speeds the dynamic pressure causes a ram air ...
    (rec.aviation.military)