262 breaking sound barrier

The Wasserfall proved to be pretty much a complete failure as a SAM. The few German launches showed the difficulty of guiding it by optical radio control from the ground. The few US postwar launches showed how poor it was as a performer.
The Germans might have been ahead in missiles but they were badly trailing in guidance and tracking systems.
Sänger's "Silverbird" was another of those Nazi wet dream projects that just diverted resources from more useful and practical projects. As we now know some 60 or so years later a mostly aluminum with minimal stainless steel and no titanium in its skin or structure would never have stood up to the heat and stresses imposed by what Sänger was proposing. Just the lack of knowledge of the Earth's outer edge of the atmosphere and of near space flight alone doomed the project.

 

That's very true about the Wassefall T.A.
Guiding it by sight was very tricky unless they made a warhead powerful enough to explode amongst a formation and do significant damage.
The Henschel glide bomb and Fritz X used a similar guidance system and scored a few hits on ships until the allies devised a suitable jamming system.
The original 100kg warhead on the Wasserfall was replaced with a larger 300+kg warhead in the hope that a general detonation in the centre of a formation would bring down bombers even if not hit directly.
They also produced a radar guidance system for the Wasserfall known as Rheinland but they were already aware that an infrared guidance system was required to autodirect the craft to target. It was diversion of resources to inappropriate programs and restrictions and obstructions to these developments that greatly held back the project.
An interesting project was the Hs 293 D which was a TV guided missile with a TV camera in the nose and broadcast its picture back to the launch plane with a 4km broadcast range. I have some video of this in operation which I might try to post on Youtube although I'm digressing from the thread topic
The obstruction of the Wasserfall's development frustrated Albert Speer who wrote post war:

"To this day, I am convinced that substantial deployment of Wasserfall from the spring of 1944 onward, together with an uncompromising use of the jet fighters as air defense interceptors, would have essentially stalled the Allied strategic bombing offensive against our industry. We would have well been able to do that -- after all, we managed to manufacture 900 V2 rockets per month at a later time when resources were already much more limited."

 

Some interesting comments from here Leduc, the test flights regarding the french Leduc ramjet fighter prototype:


On April 21st, 1949, after being released overhead Blagnac, test pilot Jean Gonord lit up the engine and established a climb using only the ramjet engine.


During the war, various tests had been conducted (particularly in the USSR and in Germany, but also in the United States) on ramjet engines installed experimentally on transporter airplanes. This type of propulsion was even used on some gun shells to increase their range, and many other projects were born as well. However, the flight of the Leduc 010 on April 21st 1949 with its ramjet operating represents the first flight of an aircraft solely propelled by a ramjet engine.


After this success, the tests were conducted with full force, and in just a few flights, the Leduc 010 proved the extraordinary capabilities of the "athodyd" engine, in particular its incredible rate of climb.
Even before the cabin was pressurized, Gonord found itself propelled to 11, 000 meters in just a few minutes. During another flight, it was the high-attained airspeed, which took him by surprise: upon reaching Mach 0.85, he encountered the violent effects of compressibility, which resulted in bounces of more than 600 meters of altitude. It was undoubtedly the first French airplane to experience this phenomenon.

The Leduc was air-launched from a carrier plane and started its engine at 200mph at which it began to accelerate under ramjet power.
On its first flight the Leduc 010 achieved 680km'hr at half throttle and later flew at 830km'hr at half throttle.



Postwar, Sänger went on to work in France and helped develop the composite engine in the Griffon. It was the first supersonic aircraft with a ramjet.
Although also fitted with a turbine, the griffon rather resembles the Sänger engines being tested on the back of the Dornier.


The following page gives some details on the silverbird and describes Stalin's postwar attempt to kidnap Sänger Eugen Sänger, Irene Bredt and the Long Range Rocket Bomber



Returning the topic to the original discussion and thread title , the transcript from the 1946 test program is very interesting:
page 13 of the "Me 262 A-1 Pilot's Handbook" issued by Headquarters Air Materiel Command, Wright Field, Dayton, Ohio as Report No. F-SU-1111-ND on 10 January 1946:

"Speeds of 950 km/h (590 mph) are reported to have been attained in a shallow dive 20° to 30° from the horizontal. No vertical dives were made. At speeds of 950 to 1000 km/h (590 to 620 mph) the air flow around the aircraft reaches the speed of sound, and it is reported that the control surfaces no longer effect the direction of flight. The results vary with different airplanes: some wing over and dive while others dive gradually. It is also reported that once the speed of sound is exceeded, this condition disappears and normal control is restored."

There is a lot of discussion about the high speed buffeting experienced by numerous aircraft and the loss of control experienced by Heini Dittmar at 1000km/hr in 1941 in the Me163a but most discussions ignore the last line of the handbook text.
What is significant if the text is genuine (apparently it is but I've never seen a copy to confirm) is the resumption of control above mach 1.
That is quite different to people claiming to have achieved mach 1 just because they experienced severe buffeting. We know that buffeting can be experienced well before mach 1. The significant thing is reports that buffeting stopped as speed increased and control resumed and then buffeting returned as aircraft slowed and subsonic flight resumed.
Fascinating for a report from 1946. Such characteristics may have been known by scientists operating the supersonic windtunnels and flight control systems for the wasserfall which obviously were steerable at supersonic speed, but are interesting from what appears to be a summary of test results from manned flight tests of the Me 262 by allied personnel.
If the document is genuine, can anyone suggest how the test pilots could have so accurately described transonic behaviour and the return of control in the supersonic region? It's a 1946 document.

 

If I may refine on this, this was not for lack of sophistication, they liked a "what works" approach. Whatever was done had to be practical, if it was to exist, it was to kill nazis and quickly, no time for cloud-cuckoo research. Development there was, fact is that in 1945 they were flying Yak-9s and La-5s, not Polikarpov I-16s, or were they?

 

I never had a problem... must be and IE issue, get firefox!!!

Now that is very interesting about the 262. If they knew that it could reach and pass the sound barrier in flight why they didn't continue with it to set records? Maybe it was in wind tunnel testing? Very interesting.

I dont know of any nation that stopped research during the war... maybe France but that is for other reasons. In Russia they were working on all kinds of toys, some of which we use today for example the AK-47 and the SKS. The IS series tanks which were the base for most of the future tanks in Russia. England was working on jet planes, and USA was building nukes. Research has to happen!

 

The test reports of the 262 and Mütke's disputed claims refer to engine flameout around mach 1 so that the planes only achieved Mach 1+ for a few seconds at best in the steep dives and then rapidly turned into disintegrating gliders! There was a rocket development fitted to BMW engines on the 262 as can be seen in this video: http://www.xs4all.nl/~jqmgrdyk/jetpower/Me-262-bwm003r.mpg
The Germans were already developing aircraft with the intent of supersonic flight rather than by accident as in the case of the 262 and development along these lines were more worthy.

Interesting to note that even conventional passenger airliners have travelled supersonic in dives such as the Boeing 727-31 TWA flight 841 which went supersonic in an accidental dive in 1979. It managed to recover and land safely. On August 21, 1961 a Douglas DC-8 broke the sound barrier at Mach 1.012 or 660 mph while in a controlled dive through 41,088 feet. The purpose of the flight was to collect data on a new leading-edge design for the wing.
The DC-8 Supersonic Flight
Boeing reports that the 747 broke the sound barrier during certification tests.
John Roundhill, VP of marketing for new airplane programs at Boeing states:" the 747 was also tested at Mach 1 in a dive,"
A China Airlines 747 broke the sound barrier in an unplanned descent from 41 000 feet to 9500 feet after an in-flight upset on February 19, 1985

 

A sonic bang from a 747 must be something out of the ordinary

 

I saw a B-52 do a barrel roll... do that while supersonic!

 

Why do we think the rockets were for supersonic flight instead of take off?

 

We don't but I only linked it out of interest. If a 262 was in the transonic range (and still in one piece!) then speculatively a rocket boost could have pushed it over the line even if the turbines had flamed out.

There is another claim that Heini Dittmar went supersonic in the Me163a V4 that I think was also flown by Hanna Reitsch.
He is now well known to have officially reached 1004.5km/hr in the rocket plane and had throttled back approaching this speed due to buffeting.
Mano Ziegler who was a friend of Dittmar apparently wrote in his book Me163 that the rocket went supersonic and that sonic booms were reported on the ground.
The 163 had a 14 percent thick wing root and 8 percent at the tips.
Dittmar lost control on his 1004.5km/hr flight.
On 6 July 1944 Heini Dittmar reached with the comet Me 163BV18 VA + SP a speed of 1130km / h

 

There's an intriguing piece of film footage from the Lippisch archives of a P13a gliding in for a landing in a hilly region of German occupied territory in 1944 or 45.

http://www.youtube.com/watch?v=MvtxjSrImHw

Although the DM1 apparently never flew, at the very least a large glider mockup of the P13a did fly as this video obviously demonstrates.
Notably, the P13a in the old film sports the ramjet intake nozzle and seems to sport the walter rocket exhaust nozzle at the base of the tail. It has the forward landing bulge skid under the nose and many of the production features not integrated in the DM1.

 

Nice footage. Must have been exhilarating. You have to love building airplanes. I wonder if it was a glider or a working prototype, maybe on a jet engine for airframe tests, or maybe a full prototype.

 

What the youtube above means is that the designers were ok, only they were working for the wrong boss...

That wind tunnel with all that trestle wood like I have in my shed is priceless!

 

You have a wind tunnel in your shed... I am on my way.

 

On supersonic wind tunnels:

Since lately I've been doing quite a bit of research on early surface-to-air missiles and other late WW 2 advanced technology, I've come across some interesting stuff. In the US, supersonic wind tunnels became an interest item late in WW 2 because of practical needs. Prior to that, they were largely ignored beyond basic research and remained tiny in size.
The Germans early on, got into building much larger ones that had little or no practical application and were really mostly just a waste of time, resources, and money.

Anyway, in the US, the first large supersonic wind tunnel was built to support Project Bumblebee. That project was run by the US Navy to develop a long-range SAM missile that eventually became the Talos. In late 1944 and into 1945 Bumblebee was firing ramjet missiles at speeds up to approaching Mach 2 at ranges of 12 to 15 miles and 35,000 feet. A wind tunnel to support design and testing of ramjet engine inlets was necessary so the Navy built a large wind tunnel to support that.

This became the "Daingerfield Project." Later known as the Ordinance Astrophysics Lab (ORL), this wind tunnel was one of the largest in the world at the time. It would go on to be crucial to the US space program in the 60's and 70's. It was also where that wonderful product WD 40 was invented.

Daingerfield TX was chosen because of the Lone Star Steel plant there which already possessed the necessary blower motors to produce supersonic windspeeds along with being relatively in the middle of nowhere.

Secret Cold War military lab embedded at steel plant - East Texas Journal
TSHA | Ordnance Aerophysics Laboratory (tshaonline.org)

 

Concur. One thing we discovered is the buffetting would make the plane uncontrollable. The stabalizer had to be one piece and the entire surface moved instead of part of it. The Me-262 had a traditional stabalizer. Now, the Me-163 is also more plausible as it didn't have a stabalizer. I dunno though. I'm no aero-engineer.

 

Let me toss this in as an additional nail in the coffin of the P 13. The US captured a prototype and actually did extensive wind tunnel testing of it post war.



This is an 'improved' design that the NACA and US did on the original because they found issues with it.



Since the P 13 had a plain--that is no shock diffuser in the ramjet inlet, it would have had immense difficulty keeping the engine running at supersonic speeds. EVERY supersonic ramjet has a shock diffuser cone in the inlet.

Lippisch DM 1 Reconsidered - Part 1 | National Air and Space Museum

Lippisch DM 1 Reconsidered - Part 2 | National Air and Space Museum

Lippisch DM 1 Reconsidered - Part 3 | National Air and Space Museum

Lippisch DM 1 Reconsidered - Part 4 | National Air and Space Museum

Essentially, no, the P 13 wasn't going to be a supersonic anything.