Author Topic: First pass speed of sound (Read 1977 times)

Wilbus · « **Reply #30 on:** July 13, 2004, 03:19:19 AM »

Me 262 A-1 Pilot's Handbook, ref: F-SU-111-ND dated 10 January 1946. Issued by Headquarters AIR Material Command, Wright Field, Dayton, Ohio. Classification cancelled; 3 June 1955.

So it seems even the US admited the 262 was capeble of supersonic flight if pushed hard enough in a dive.

Overlag · « **Reply #31 on:** July 13, 2004, 10:37:12 AM »

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Originally posted by ra
You should read it more carefully. They are talking about the speed of the airflow around the aircraft.

maybe you should too?

it says that once the speed of sound is exceeded, the plane regains control....

Widewing · « **Reply #32 on:** July 13, 2004, 10:45:33 AM »

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Originally posted by Wilbus
Uhm Widewing acording to you the critical mach of the 262 is well bellow the critical mach of a Spitfire, which I don't believe at all as it would mean a 262 could be outdived by a 262.

No, you CAN NOT be SURE the 262 never broke the sound barrier.

"The other" pilots who claimed they did it were in prop planes, and a prop plane can't go through the sound barrier as the prop, once the plane reaches a certain speed, acts more like a break.

Lots more interesting stuff to read from the page, all of it makes sence and has got a good point. Also, MACH 1 is quite a bit easier to reach at 30,000 feet then it is at sea level.

In my Book Mutke was the first to go through the sound barrier and live to tell the tale.

You Luftwaffe fanatics will never let go of your delusions, will you?

You post a page from a document that clearly defines the standard conditions and effects of compressibility, NOT transonic flight, and expect that to be taken as proof the 262 was capable of exceeding Mach one. The tip of a bullwhip can exceed Mach one, so is the bullwhip as a whole supersonic? LOLOLOLOLOL

As to the Spitfire being faster in a dive than the 262, without its prop the answer is yes. A late-model Spitfire was dived from 44,000 feet in 1946. As it reached 25,000 feet the drag rise on the prop resulted in the prop hub failing. All five blades flew off into space. Continuing down, out of control, the Spitfire attained Mach 0.90 before increasing density and temperature slowed its physical and relative velocity to that where the pilot was able to regain control. After a deadstick landing, the aircraft was examined and promptly written off as being too damaged to repair.

NAA's XP-86 had a considerably lower chord to thickness ratio wing, of far greater sweep (and a laminar flow design to boot). The XP-86 had much lower drag too. Even then, about all it could manage was Mach 1.04 in a sustained dive. Yet, you expect us to accept that the 262, with its wing twist and tail flutter issues as well as its far greater drag, could come within 3% or 4% of the Sabre's speed in a dive?! It's laughable.

Here's an interesting discussion on WWII fighters and the sound barrier. It demonstrates the extremes of stupidity as well as provides excellent data and reasoning. Have a look, and read the whole thread. Take note of the speeds shown for the Spitfire and P-47 as well as why the 262 could never exceed Mach one.

Axis History Forum

My regards,

Widewing

Widewing · « **Reply #33 on:** July 13, 2004, 10:58:16 AM »

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Originally posted by Overlag
maybe you should too?

it says that once the speed of sound is exceeded, the plane regains control....

No, it's talking about the effects of compressibility. 1,000 km/hr is nowhere near Mach one at any altitude where the Me 262 could attain that speed. Hell, it was common to exceed 1,000 km/hr diving a P-47. Test pilot Herb Fisher exceeded 600 mph routinely doing dive tests with a P-47D. However, at 20,000 feet, that is barely above 0.82 Mach, a long, long way from Mach one.

My regards,

Widewing

Dune · « **Reply #34 on:** July 13, 2004, 03:04:52 PM »

I have heard two reasons why Welch's accomplishment wasn't recognized by the USAF. For one, it wasn't approved and would have seriously taken the glory away from their X plane and Yeager. Secondly, I have also heard they didn't want the Russians to know the full capabilities of the Sabre.

GRUNHERZ · « **Reply #35 on:** July 13, 2004, 03:24:41 PM »

Whats more significant supersonic only in a dive or supersonic in level flight - granted B29 ride up and short duration rocket power only?

Did sabres use supersonic dives to evade mig 15s in Korea?

IronDog · « **Reply #36 on:** July 13, 2004, 09:39:51 PM »

Read story about guy breaking the sound barrier in a Me163.The
163 was hooked up to a Heinkel 111,and taken to a high altitude,then released.Being it didn't have to burn it's fuel to gain altitude,it was able to use the extra fuel to generate a speed sufficient to break the sound barrier.As I recall,the pilot lost all control for a period of time,and was just able to gain control back in time to avert disaster.I don't recall the pilots name,maybe Wilbuz can help on that.I seem to remember reading a story by a F4U pilot,saying that he broke the sound barrier in a prop plane.I'm no expert,and I don't know if that's even possible.
IronDog

ra · « **Reply #37 on:** July 13, 2004, 09:58:58 PM »

Before you believe tales about this or that WWII fighter breaking the sound barrier, keep in mind that Geoffrey DeHavilland died trying to break the sound barrier in late 1946 in a DH-108, which was specifically designed for the purpose. Do you believe that DeHavilland would have bothered creating an all-new design if there was already a supersonic design in existence? And that they would have failed where the earlier designs succeeded?

ra

mora · « **Reply #38 on:** July 14, 2004, 12:06:18 AM »

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Originally posted by GRUNHERZ
Did sabres use supersonic dives to evade mig 15s in Korea?

Yes they did. Mig-15s were not able to go supersonic.

Wilbus · « **Reply #39 on:** July 14, 2004, 04:45:21 AM »

The 163 never carried enough fuel to brake the sound barrier, even though they launched it from a 111 it still didn't have anough fuel.

As for Prop planes such as the F4u, no prop plane is capeble of going through the sound barrier simply because, once a certain speed is reached, the prop it self acts as a brake instead of as a pulling prop.

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No, it's talking about the effects of compressibility. 1,000 km/hr is nowhere near Mach one at any altitude where the Me 262 could attain that speed.

Well the 262 in question was flying full speed and then put in a steep dive from 36,000 feet, up there MACH 1 is alot easier to get to then down low.

Widewing,

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You Luftwaffe fanatics will never let go of your delusions, will you?

Is that needed to make yourself feel good? That's pathetic IMO but I guess that's the only way you can feel really good about yourself.

Difference between me and you is that I keep an open mind, I don't know wether the 262 actually broke the barrier, however, I consider it a possibiltiy and untill someone flies a real 262 again and actually tries it, I will still consider it a possibility untill proven wrong. What I am pretty sure of though is that Yeager wasn't the first to exeed it, only the first to do so in level flight.

IronDog · « **Reply #40 on:** July 14, 2004, 09:03:58 AM »

Wilbuz thanks for reply.Set me straight on that one.Guess my old feeble memory failed me again.

IronDog

Wilbus · « **Reply #41 on:** July 14, 2004, 11:44:44 AM »

My plessure Irondog

!

hogenbor · « **Reply #42 on:** July 15, 2004, 08:25:07 AM »

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Originally posted by Widewing
You Luftwaffe fanatics will never let go of your delusions, will you?

I can't help but making the remark that a slight bias towards American knowledge and equipment is evident in your posts Widewing, but I'm still impressed enough to believe all of your statements. Besides, you ARE American

No matter how many people WANT the 262 to be the first to go supersonic, this does not mean it really was. Still, it makes a good story.

With a keen interest in aviation but no technical background in it how can I ever comment on if it was likely that the 262 broke the sound barrier? It does not seem likely, but what do I know? Still I would vote for no. That having said, we have a flyable 262 around in Texas, as close to the original as we will ever get, but with much more powerful engines. Shall we ask them to try how fast it will go? (For those not in on irony, this is a rather poor joke)

I'd like to say that I'm not a Luftwaffe fanatic but the sometimes fantastic ideas and designs (born mostly out of desperation) that the Germans came up with really tickles the imagination. And no-one will refute that the U.S and the Soviet Union both made use of German knowledge in their jet and rocket programs.

Widewing · « **Reply #43 on:** July 15, 2004, 10:04:51 AM »

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Originally posted by hogenbor
I can't help but making the remark that a slight bias towards American knowledge and equipment is evident in your posts Widewing, but I'm still impressed enough to believe all of your statements. Besides, you ARE American No matter how many people WANT the 262 to be the first to go supersonic, this does not mean it really was. Still, it makes a good story.

I admit that my remark was somewhat insensitive. I do tend to get short tempered with people who, rather than research the technology, accept speculation and uneducated observations of untrained (technically speaking) pilots as gospel. I have no stomach for such reasoning regardless of a person's national origin. A great many pilots have claimed to have broken the sound barrier due to observing strange behavior at high speeds. I know of one P-47 pilot who, to this very day, is convinced that his P-47 went supersonic. Despite being informed to the contrary, he argues that he "knows what he saw". Thus far, I have avoided telling him that he is a certified idiot. I have even gone as far as to have a former Republic test pilot try to explain why it was impossible. He hung up on the test pilot half-way thu the explanation.

I have seen similar "thickheaded" reasoning when it comes to the Luftwaffe. You know, the old "we were beat my numbers argument". Now, we know that the Luftwaffe was out-numbered towards the end of the war. However, Allied technology produced some of the finest aircraft of the war, piloted by better trained men. Yeah, German technology was fantastic. Yet, in many areas they were behind the western Allies.

There is much to admire Germany for, but let's not be fanatical about them as it blinds one to reality.

I have discussed the 262 question with friends who work at Dryden, people with doctorates in aeronautical engineering. Each one has stated that the Me 262 was no more capable of exceeding Mach one than the F-80 or Meteor. Although all were certainly fast aircraft compared to prop driven fighters of their generation, they were all utterly sub-sonic.

Yet, some people, like that P-47 pilot, will never accept facts that crush their personal delusions as if their very identity would be lost as a result.

My regards,

Widewing

hogenbor · « **Reply #44 on:** July 15, 2004, 11:10:11 AM »

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Originally posted by Widewing
I have even gone as far as to have a former Republic test pilot try to explain why it was impossible. He hung up on the test pilot half-way thu the explanation.

Which only proves that thickheadedness can be found among all nationalities

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I have seen similar "thickheaded" reasoning when it comes to the Luftwaffe. You know, the old "we were beat my numbers argument". Now, we know that the Luftwaffe was out-numbered towards the end of the war. However, Allied technology produced some of the finest aircraft of the war, piloted by better trained men. Yeah, German technology was fantastic. Yet, in many areas they were behind the western Allies.

There is much to admire Germany for, but let's not be fanatical about them as it blinds one to reality.
[/B]

Too true. Let's be realistic and open minded shall we? (Too much to hope for on this BBS). But please don't get worked up about people who confuse fact and fiction, they're not worth it. Everybody is entitled to an opinion and no matter what you say, some people will die being utterly convinced that the Me-262 or the P-47 for that matter broke the sound barrier, no matter how much reasoning you heap upon them. Personally, I don't care if they believe that a Fokker Dr-I did it.

That having said, what if the test pilot of the Texas 262's initiates a dive, runs into compression and breaks the sound barrier? As you say, experts have stated that it would be impossible. I wouldn't go that far. Extremely, extremely unlikely, yes. Impossible no. Why? Scientists are only human after all. Besides, leaves the 'Luftwaffe fanatics' a bit of hope.

Regards,

Ronald