F-86 and sound barrier

Hi all,

The 'Welch/Yeager' argument conveniently ignores the NAA flight records for the
period in question. Either Blackburn didn't have these for his book or chose to
ignore them, but they clearly detail Welch's undercarriage problem on October
1, 1947 and also detail the redesign necessary prior to the next flight with
the undercarriage functioning. To suggest that NAA had to bolt the gear down to
prevent Welch going supersonic is ridiculous.

Incidentally, Blackburn also conveniently neglects to include the fact that
Welch had a P-82 chase for the first flight; it would have been difficult (not
to say crass) for Welch to sneak off and break the sound barrier with a chase
craft trying to determine the damage caused by the undercarriage malfunction
which happened during climb-out on flight number 1.

Much as I love the F-86, it wasn't first to Mach 1. There is (and always has
been) no subsitute for good research.

Duncan

On 22 Sep 2003 17:24:26 GMT, (DunxC) wrote:

Hi all,

The 'Welch/Yeager' argument conveniently ignores the NAA flight records for the
period in question. Either Blackburn didn't have these for his book or chose to
ignore them, but they clearly detail Welch's undercarriage problem on October
1, 1947 and also detail the redesign necessary prior to the next flight with
the undercarriage functioning. To suggest that NAA had to bolt the gear down to
prevent Welch going supersonic is ridiculous.

Blackburn does not ignore the problem with the nose gear cylinder. I suggest
you re-read his book (I read the galleys months before the book went into
print and received one of the first books off the press).

The next flight was on October 9, before then, the NAA guys had already solved
the nose gear problem and wanted to install the fix ASAP... Over objections,
they were ordered to "bolt" the gear down and disable the handle. It seems the
USAF wanted their inspectors to check the fix prior to installation. Should
anyone be surprised that they said it may take two weeks to do the inspection?
As it was, the inspection did not occur until October 11, and it took two days
to install and do a series of drop checks on the jacks.



Incidentally, Blackburn also conveniently neglects to include the fact that
Welch had a P-82 chase for the first flight; it would have been difficult (not
to say crass) for Welch to sneak off and break the sound barrier with a chase
craft trying to determine the damage caused by the undercarriage malfunction
which happened during climb-out on flight number 1.

Again, you are flagrantly incorrect. Bob Chilton was flying the F-82 chase
plane and he orbited at 15,000 ft while Welch went off to wring out the Sabre.
Welch did not "sneak off", he merely informed Chilton that he was going up to
"feel it out". Chilton confirmed that the gear was up and locked visually prior
to Welch climbing out.

By the way, the "damage" was the result of a design fault in the nose gear
extension mechanism, not a result of excessive speed on climbout. The gear
would retract, but not extend fully due to aerodynamic forces. Once airspeed had
dropped to below 80 knots, the cylinder was able to fully extend and lock the
gear over-center.


Much as I love the F-86, it wasn't first to Mach 1. There is (and always has
been) no subsitute for good research.

Duncan

I agree, and you might want to practice it yourself.

My regards,

Widewing (C.C. Jordan)
http://www.worldwar2aviation.com
http://www.netaces.org
http://www.hitechcreations.com

(Corey C. Jordan)

wrote:Again, you are flagrantly incorrect. Bob Chilton was flying the F-82
chase
plane and he orbited at 15,000 ft while Welch went off to wring out the
Sabre.

Anyone know what happened to Bob Chilton? Thx.
VL

By the way, the "damage" was the result of a design fault in the nose gear
extension mechanism, not a result of excessive speed on climbout.

The damage was caused by fast retraction of the nose gear on take-off (because
of the weak cylinder against building airspeed); the solution to that one was
to fit a restrictor in the hydraulic 'up' line. Any other problems were linked
to, but not the cause of, the damage.

The NAA logs are quite detaioled on this.

Duncan

Exceeding M1.0 in either the Sabre or the Dog was no big deal. You
just pointed them straight down from 40+ and didn't fight it if it
wanted to roll around .95(flap rigging, usually).
Question: didn't Edwards get boomed when Welch went supersonic?
Walt BJ

On 23 Sep 2003 07:47:41 -0700, (Walt BJ) wrote:

Exceeding M1.0 in either the Sabre or the Dog was no big deal. You
just pointed them straight down from 40+ and didn't fight it if it
wanted to roll around .95(flap rigging, usually).
Question: didn't Edwards get boomed when Welch went supersonic?
Walt BJ

It certainly did!

Prior to heading back to North American to debrief with the engineers, Welch
telephoned a friend that he had briefed the day before about what to be
listening for. Excitedly, his friend related that they had been nearly blown out
of bed by a terribly loud ba-boom. The time was noted and it corresponded to
George's dive.

Major General Joseph Swing heard the boom and reported it to Stu Symington.
Hundreds of others heard it too. Many wives ran outside looking for the
tell-tale plume of smoke indicating a crash, but there wasn't any smoke to see.

Ask any of the NAA guys (or the Bell crew as well) who were there at the time.
Welch's boom was quite loud, far more so than Yeagers would be (which makes
sense when you consider that Welch was diving towards the base, whereas Yeager
was in level flight at higher altitude).

My regards,

Widewing (C.C. Jordan)
http://www.worldwar2aviation.com
http://www.netaces.org
http://www.hitechcreations.com

"Corey C. Jordan" wrote:

On 23 Sep 2003 07:47:41 -0700, (Walt BJ) wrote:

Exceeding M1.0 in either the Sabre or the Dog was no big deal. You
just pointed them straight down from 40+ and didn't fight it if it
wanted to roll around .95(flap rigging, usually).
Question: didn't Edwards get boomed when Welch went supersonic?
Walt BJ

It certainly did!

Prior to heading back to North American to debrief with the engineers, Welch
telephoned a friend that he had briefed the day before about what to be
listening for. Excitedly, his friend related that they had been nearly blown out
of bed by a terribly loud ba-boom. The time was noted and it corresponded to
George's dive.

Major General Joseph Swing heard the boom and reported it to Stu Symington.
Hundreds of others heard it too. Many wives ran outside looking for the
tell-tale plume of smoke indicating a crash, but there wasn't any smoke to see.

Ask any of the NAA guys (or the Bell crew as well) who were there at the time.
Welch's boom was quite loud, far more so than Yeagers would be (which makes
sense when you consider that Welch was diving towards the base, whereas Yeager
was in level flight at higher altitude).

Correct me if I'm wrong, but didn't the XP-86 still have the 4,000 lb. thrust J35C-3
at that time? Quite a ways down on thrust from the 5,200 lb. J47-13 of the F-86A,
and the top speed of the XP-86 in the only reference I have handy is given as 618
mph @ 14,000 ft. and 575 mph @ 35,000 ft. (M0.875), versus the 677 (presumably lower
down) of the F-86A. The XP-86 is credited in the same source with first exceeding
Mach 1 on 26 April 1948, but it's implied (not explicitly stated) that it did so on
a 3,920 lb. thrust J35-A-5, and that the J47 was first installed in the F-86A. This
seems more than a bit odd, to install an untried engine in the production a/c
without flying it in the prototype first.

I've read pilot's accounts that say that some F-86As would 'hang up' and not quite
make it through the mach if you didn't do the roll in right, which suggests that the
XP-86 with its lower thrust might well have trouble. Of course, if exceeding mach
was mainly a question of drag rather than excess thrust, then it shouldn't have been
a major problem. I've just always wondered.

Guy

o on
a 3,920 lb. thrust J35-A-5, and that the J47 was first installed in the
F-86A. This
seems more than a bit odd, to install an untried engine in the production a/c

The three XF-86As (sic) were all brought up to 'F-86A-1' standard by the time
they were delivered to the Air Force; that included fitting the J47.

Duncan

In article ,
Guy Alcala writes:
"Corey C. Jordan" wrote:

On 23 Sep 2003 07:47:41 -0700, (Walt BJ) wrote:

Exceeding M1.0 in either the Sabre or the Dog was no big deal. You
just pointed them straight down from 40+ and didn't fight it if it
wanted to roll around .95(flap rigging, usually).
Question: didn't Edwards get boomed when Welch went supersonic?
Walt BJ

It certainly did!

Prior to heading back to North American to debrief with the engineers, Welch
telephoned a friend that he had briefed the day before about what to be
listening for. Excitedly, his friend related that they had been nearly blown out
of bed by a terribly loud ba-boom. The time was noted and it corresponded to
George's dive.

Major General Joseph Swing heard the boom and reported it to Stu Symington.
Hundreds of others heard it too. Many wives ran outside looking for the
tell-tale plume of smoke indicating a crash, but there wasn't any smoke to see.

Ask any of the NAA guys (or the Bell crew as well) who were there at the time.
Welch's boom was quite loud, far more so than Yeagers would be (which makes
sense when you consider that Welch was diving towards the base, whereas Yeager
was in level flight at higher altitude).

Correct me if I'm wrong, but didn't the XP-86 still have the 4,000 lb. thrust J35C-3
at that time? Quite a ways down on thrust from the 5,200 lb. J47-13 of the F-86A,
and the top speed of the XP-86 in the only reference I have handy is given as 618
mph @ 14,000 ft. and 575 mph @ 35,000 ft. (M0.875), versus the 677 (presumably lower
down) of the F-86A. The XP-86 is credited in the same source with first exceeding
Mach 1 on 26 April 1948, but it's implied (not explicitly stated) that it did so on
a 3,920 lb. thrust J35-A-5, and that the J47 was first installed in the F-86A. This
seems more than a bit odd, to install an untried engine in the production a/c
without flying it in the prototype first.

The rather low thrust of the XP-86s is quite true, but in the case of
diving one through the Mach, it's pretty much irrelevant. The big
factor in barging into the region o rising drag isn't the 1,000-1,200#
of pusth that you're getting from the J35 at 40,000', bit the 13,000#
of gravity assist that you get in the dive. Of course, with such a
low thrust/weight, it took forever to get up there.

Roland Beamont made a "flying trip" to the U.S. in '47-'48 to assess
the various projects that were going on, and to get some first-hand
experience with American aircraft developments. (He flew the P-80A,
the P-84A, a B-45 prototype, and an XP-86) He did, in fact, make a
transonic dive in a J35 power XP-86. He did a series of article
about this trip, includig the flight test reports, in "Aeroplane" back
in 'bout 1988 or 1989. They were also chapters in "Testing the Early
Jets".

I've read pilot's accounts that say that some F-86As would 'hang up' and not quite
make it through the mach if you didn't do the roll in right, which suggests that the
XP-86 with its lower thrust might well have trouble. Of course, if exceeding mach
was mainly a question of drag rather than excess thrust, then it shouldn't have been
a major problem. I've just always wondered.

It's not so much a matter of thrust, as making sure you've got enough
dive angle on before you start getting into the thicker air below,
say, 20,000'. If you didn't get it pointed pretty much straight down,
you'd be running into thick air pretty fast.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

On 23 Sep 2003 05:53:00 GMT, (DunxC) wrote:

By the way, the "damage" was the result of a design fault in the nose gear
extension mechanism, not a result of excessive speed on climbout.

The damage was caused by fast retraction of the nose gear on take-off (because
of the weak cylinder against building airspeed); the solution to that one was
to fit a restrictor in the hydraulic 'up' line. Any other problems were linked
to, but not the cause of, the damage.

The NAA logs are quite detaioled on this.

Duncan

According to Roy Ferrin, the actuator was replaced with one having a
larger diameter piston, and the door linkage was adjusted to close a tad sooner.
I can't see how a flow restrictor in the line will compensate for a lack of
force resulting from inadequate pressure area. If you want more push for a given
hydraulic pressure, you need a larger cylinder.

My regards,

Widewing (C.C. Jordan)
http://www.worldwar2aviation.com
http://www.netaces.org
http://www.hitechcreations.com