Supersonic 747

[Iceman49]

Our squadron had a C-141 that had a yaw damp problem at 410, did a split-s and recovered at 12000, supposedly went mach1+ in the dive.

[Meikleour]

SpannerKL

Thanks for your input however are you sure that this is active? Re-reading my copy of `Handling the Big Jets` page 266 where DP Davies the then CAA Chief Test pilot discusses the B747 certification flying programme he says that the Stab Trim Brake mechanism was made to be compatible with a Mach Trimmer however that was deleted from the final design. Also the flighdeck has no such controls and the MEL makes no mention of a Mach Trim system therefore I assume that it is not in fact installed. The aircraft exhibits a natural pitch-up at M0.94

[ChristiaanJ]

Bell X-1 and F-104 have straight wings, yes, but they DO have thin airfoil profiles (which doesn't help with low-speed performance... the F-104 has blown flaps to at least mitigate that effect).

To go back a moment to the initial question, I think we can state.... :
yes, most or all of the big 'uns (and probably most of the smaller spamcans) CAN reach Mach 1 and slightly over. Some have done so deliberately (such as the DC-8), some due to circumstances outside their volition....

Just don't try this at home, kids. You may end up having to explain a bent airframe.

And while we're on the subject...
I suppose you know that the critical Mach number of the Spitfire is M0.92?
And that it's quite plausible that at least one Me-262 broke the sound barrier towards the end of WWII?
And that it's most likely that George Welch went over Mach 1 in the XP-86 Sabre, weeks before Chuck Yeager did the "Right Stuff" ?

I like cans of worms....

[EDML]

Aerodynamically it makes sense to have swept back wings below M 1.0
(in the transsonic range) to avoid the onset of Mach effects on certain
parts of the airframe.

Once you are above M 1.0-1.1 that does not matter anymore as everything
is supersonic anyway.

Furthermore there are even people around claiming that the drag of a
straight wing at full supersonic speeds (> M 1.3-1.5) is even lower than
that of a swept back wing - however I do not fully believe that.

EDML

[CV880]

You can read a Douglas press release and an extract of the flight test report for the supersonic DC8 flight at www.dc-8jet.com. The attached photograph indicates it was a Canadian Pacific DC8-40 series with RR Conways that was testing a revised wing design (Since Douglas increased the chord of the DC8's leading edge to improve cruise performance at some point in production I guess this was a part of the testing of that production change).

[Pugilistic Animus]

CV88: I was happy to see that Douglas report--- It seems I have the year wrong in my post---DC-8 Supersonic 1961--- still the first!

ChristaansJ: actually I believe the Boeing figures were TMN not IMN---so position error and compressibility errors were accounted for were accounted for

--- the account I read of the test was from Davies' "Handling the Big Jets", I have to take a look

[Brian Abraham]

And that it's quite plausible that at least one Me-262 broke the sound barrier towards the end of WWII?
And that it's most likely that George Welch went over Mach 1 in the XP-86 Sabre, weeks before Chuck Yeager did the "Right Stuff" ?

It has been recognised that George Welch was the first. Chucks claim to fame is being the first to do it in level flight (Mach 1 that is). As to the 262, the claim that it did,or may have, has been put to rest as a no. There is a comprehensive post war test report done in the US somewhere on the web.

[Anotherflapoperator]

That 146 incident must have been pretty hairy up to the point of failure...the poor old thing only has a VNe of 305kts or .72M on the -300 model. The 146 is a slow boat, and the thick slow speed wing is not happy at high speed at all. -200s tend to have a little hump or tuck at .67 but the memory's fading away nowadays.

[ChristiaanJ]

Originally Posted by Brian Abraham

As to the 262, the claim that it did,or may have, has been put to rest as a no. There is a comprehensive post war test report done in the US somewhere on the web.

There's Hans Guido Mutke's story, and there's "circumstantial evidence" in the "Me-262 Pilot's Handbook", which is the report you refer to (has been around for years, I have a facsimile copy somewhere).
See http://mach1.luftarchiv.de/mach1.htm.
I've seen better write-ups, that's just the first one, with most of the details in one place, that I pulled off Google for this reply.

My own opinion: certainly possible, quite possible, not proven.