Posted on 09/01/2021 7:32:34 AM PDT by DUMBGRUNT
A 747 at close to the speed of sound?
Test pilots at an Israeli aircraft company successfully flew a 747 freighter at 98 percent of the speed of sound in a safety demonstration for the Federal Aviation Administration.
Israel Aircraft took the speed test as part of its plans to convert old passenger 747s into freighters.
Menachem Shimol, a test pilot for Israel Aircraft, reported that its test plane reached 0.98 Mach in an 18-degree dive from 36,000 feet Sept. 30.
Pilots described the high-speed experience as ''a little frightening''but said they were confident the plane would remain controllable.
In addition, Boeing knows one case in which a 747 operated by Evergreen International made an emergency descent at speeds that exceeded Mach 1, he said.
As for the freighter that flew 0.98 Mach, Israel Aircraft reports it`s for sale, with an extensive overhaul. The price is less than $30 million.
(Excerpt) Read more at chicagotribune.com ...
I was on a very early 747 Chicago to Toyko, the movie projector had issues, we made a VERY QUICK stop at Boeing Field and picked up repair technicians, about two minutes of not rolling and took off!
Also a flight from Toyko to LA(?) with about one hundred Vietnamese babies!
Chuck Yeager is credited with being the first pilot to break the speed of sound but that record has since been modified to include the caveat, “in level flight”. The reason for this is that a German Me-262 pilot is acknowledged to have broken the sound barrier during the war, but did so while diving his plane.
Aviation Ping!.....................
As long as the topic is exploring the 747 speed envelope,
what’s the slowest speed for a 747?
I’m of the understanding it’s in the ballpark of 110 knots.
Of course, the actual stall speed depends of gross weight, vintage, configuration, flaps/gear....
what’s the slowest speed for a 747?
0..............................
Going to get technical, ground speed could be less than 0.
Would take a mighty jet stream, of course.
In level flight, a 747 would be having some major artifacts of a *sustained* flight at 110 knots.
Pitch high, perhaps buffeting. Every aircraft has different stall characteristics.
LKOL. You beat met to it.
That is still disputed. The 262 had compressibilty problems at mach .86 and the pilot would lose control.
I thought it was the ME-163 rocket fighter.
I have a copy of the original word perfect draft of tex johnsons biography as it was before being edited and several chapters cut out by the publisher
I believe a British test pilot post-WWII may have also broken the sound barrier in his jet, since his flight caused a sonic boom followed shortly by another boom as the plane crashed after control surfaces were locked by going supersonic.
It’s certainly possible that the ME-262 could have exceeded the Speed of Sound in a dive (though how it would have been recoverable is a major question). But aviation records require verification and as we say in Scuba diving, “If you didn’t get a picture, it didn’t happen.”
—”what’s the slowest speed for a 747?’
A fun topic with many variables.
“The slowest theoretical speed is the stall speed with full flaps and slats. It depends on the aircraft mass, the center of gravity location and the air density (which is dominated by altitude and temperature). Let’s assume OWE (operating weight empty) plus one pilot and conditions at Verkhoyansk (ICAO code UEBW) in Siberia in Winter. The average temperature in January there is only -50°F, so this should be a perfect combination of low and cold to produce a density of 1.522 kg/m³.
Now plug in the numbers: Minimum weight for a 747–400 is 254,500 kg, and the same source gives the stall speed in landing configuration at 280 tons with 138 knots or 71 m/s. Now correct for the minimum mass and the higher density, and the result is 118 knots or 60.72 m/s. This is as low as it gets, but no longer safe.
Multi-engined aircraft have another speed limit, called minimum control speed, which the aircraft should never fall below to be safe if an engine fails. This speed is 1.73 times higher than the stall speed for the 747–400, and even during the final approach the pilot will not drop the speed lower than 1.3 times stall speed.”
“Scotty, give me another two percent!”
“I’m giving you all she’s got, captain!”
“This is not logical...”
“STFU, Spok”
In order to keep Yeager (and the Americans, of course) on top of the Germans, they just changed the wording n the record book (adding, "in level flight") (as if that meant much to the pilot flying at the speed of sound).
It was an Me-262; the pilot’s name was Mutke. (He had dived his plane to help a fellow aviator who was under attack by a P-51; his story is out there on the internet.)
But as I've said here, there was sufficient evidence of the veracity of the claim that the official wording that described Chuck Yeager's accomplishment has since been amended to allow for it.
I think there were enough aircraft aloft at that time that could push the envelope hard enough to achieve such a feat; I don’t doubt this claim at all.
The event you are referring to wasn't recognized because there was no instrumentation to verify the claim.
Gen Robin Olds claimed he took a P-38 supersonic in a dive. The plane was known to approach mach 1 because of compressibility issues killing pilots diving the plane.
"Wheaties" Welch claimed to dive an F-86 through mach 1 and probably did not once but twice. The second time was only hours before Gen Yeager's historic flight.
Welch then went on to take the F-100 supersonic as the first jet powered US production aircraft to do that in level flight. Later in that test program, the plane killed him when he over G'd it and it disintegrated. The irony was that his chase pilot was Chuck Yeager.
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