What a beautiful landing

Reunite Gondwanaland (Mary Shafer) wrote:
No. *The M2-F2 was dangerous because of the lateral "phugoid". *It
really had to be flown feet-on-the-floor. *Check out "Runway to Orbit"
for more detail. *The HL-10 was okay.

Both the HL-10 and M2-F2 had their fair share of problems. After the
HL-10's first flight, it spent the next 15 months as a " hangar queen
" and was modified to correct stability and buffeting issues.

When the M2-F2 was rebuilt after the crash, a center vertical tail was
installed and it became the M2-F3. According to Air Force pilot Jerry
Gentry, the transformation of the M2-F2 into the M2-F3 changed "
something I really did not enjoy flying at all, into something that
was quite pleasant to fly. "


Chris

Reunite Gondwanaland (Mary Shafer) wrote:
On Fri, 27 Nov 2009 16:51:58 -0600, Pat Flannery
wrote:

I liked the HL-10, but apparently it was the worst flying of the
original ones, to the point of being dangerous.

No. The M2-F2 was dangerous because of the lateral "phugoid". It
really had to be flown feet-on-the-floor. Check out "Runway to Orbit"
for more detail. The HL-10 was okay.

No it was not, at least as originally built:
http://www.century-of-flight.net/Avi...g%20Bodies.htm

"Engineers at NASA's Langley Research Centre in Virginia developed
another lifting body design. It was designated the HL-10. The HL-10
design offered a great amount of internal volume for its size, meaning
that an operational version would be able to carry a lot of people or
cargo inside. It differed somewhat from the M2-F2 by having the rear
edges of the fuselage extended outward into angled vertical fins. The
M2-F2 and HL-10 would be dropped from the B-52, ignite their rockets to
achieve high speeds, and then glide to un-powered, "dead-stick" landings
on the dry lakebed at Edwards Air Force Base.
The M2-F2 made its first glide flight on July 12, 1966. The HL-10 made
its first glide flight in the same manner on December 22, 1966. But the
HL-10 did not fly again for 15 months because those running the program
became concerned about its safety. This was prompted in part by a number
of near crashes and temporary losses of control with the other lifting
bodies such as the M2-F2.
One of the big problems the lifting bodies had was with what is called
"flow separation." The airflow over the fuselage became turbulent and
did not flow smoothly. The HL-10 designers fixed this by extending the
leading edges of the fins (the edge that heads into the airflow) and
cambering, or curving, them."

There was also a problem with optical distortion from the bubble
nosecone, which gave the pilots the impression that they were higher
than they actually were during final approach.
That, and the problems on the first flight are discussed he
http://www.nasa.gov/centers/dryden/p...main_H-757.pdf

"The first flight of the HL-10, a glide flight, was different from the
following 36 flights in that three serious problems were encountered:
objectionable pitch control system limit cycles, overly sensitive
longitudinal stick gearing, and aerodynamic flow separation over the
upper aft portion of the vehicle. Immediately after the HL-10 was
launched, the pilot became aware of the longitudinal control system
limit cycle and the oversensitivity of the longitudinal control stick.
These problems persisted throughout the 188-second flight, with the
limit cycle becoming severe toward the latter portion of the flight
(fig. 20). Eight SAS gain changes were made during the flight; the pitch
SAS settings decreased from 0. 6 to 0. 2 before touchdown. The severe
limit cycle persisted even after the reduction in SAS gain.
The third problem, an apparently low level of roll control power, was
reported by the pilot to be only a "confusion factor." Accordingly, he
rated the lateral-directional handling qualities from 1. 0 to 3. 5.
Analysis of the flight data, however, revealed the potential seriousness
of the problem and showed that it was caused, in part, by intermittent
separation of the flow field over the upper aft portions of the vehicle.
Figure 21 illustrates the flow separation and its effects on the
vehicle's lateral-directional response characteristics. The separated
flow and the transition between separated and attached flow is best
illustrated by the tip fin flap strain-gage responses. These show a wide
band high-frequency disturbance when the flow is separated and a
relatively thin, undisturbed trace when the flow is attached. The effect
of the flow characteristics on vehicle motion is illustrated by a
comparison of the pilot's aileron input with bank angle and roll rate.
As the flow became attached, a rapid bank angle change and a large roll
rate was generated in response to existing aileron inputs and sideslip
angle (t «s 12. 8 sec and 45.0 sec). When the flow was separated,
however, large aileron inputs resulted in slight or no vehicle response
(t » 0 sec to 12. 8 sec and 20 sec to 45 sec). The rudder was effective
enough to produce sideslip when the flow was separated. The flow became
attached as angle of attack decreased below approximately 5°. At t 45
seconds, Mach number decreased enough to prevent the Mach number-angle
of attack separation (buffet) boundary from being crossed again. From
that point on, the controls functioned normally.
As a result of the flow separation problem, additional wind-tunnel tests
were conducted to identify the portion of the vehicle where separation
occurred and the aerodynamic modification to correct it. The wind-tunnel
tests (refs. 13 and 14) revealed that the separation occurred near the
tip fin leading edge and fin/body juncture and became more severe as it
moved aft over the upper surface of the vehicle. As a result of these
tests, the leading edges of the tip fins were extended and cambered to
improve the aerodynamic flow over the vehicle. In addition, the
longitudinal stick gearing was reduced, and the control system was
modified. The flight-test program was resumed, and no other problems due
to flow separation or control system malfunctions arose."

Pat

You really want to go there Bob? Honestly?

How many B-52s are still in service? Heck, how many DC-3s?

Do we need to name others?

wrote in message
...

YEAH BUT in the case of the shuttle its 40 years old.

do tell how many reusable vehicles are still in use after 40 years?

many of the parts are well past their rated lifetimes NASA shops on e
bay for ground support spares, the vehicle has killed twice, both with
known issues nasa managers dismissed as no big problem...

so mike griffin stated theres a 80% of shuttle killing again.

this from nasas own data.

do you think he was lying?

CCBlack wrote:

Both the HL-10 and M2-F2 had their fair share of problems. After the
HL-10's first flight, it spent the next 15 months as a " hangar queen
" and was modified to correct stability and buffeting issues.

When the M2-F2 was rebuilt after the crash, a center vertical tail was
installed and it became the M2-F3. According to Air Force pilot Jerry
Gentry, the transformation of the M2-F2 into the M2-F3 changed "
something I really did not enjoy flying at all, into something that
was quite pleasant to fly. "

You wouldn't have thought that the extra fin (particularly in that
position where there wouldn't have been that much airflow over it during
the final approach) really would have changed things that much, but
that's just what I read about it also.
The M2F2 crash was covered on the national nightly news the day it
occurred, and the radio communications between the aircraft and the
ground suggested that Bruce Peterson was very concerned that a
helicopter had gotten into his glide path and he was going to collide
with it ("That chopper's gonna get me!" he said twice during the final
approach, although the ground assured him there was no collision danger).
When you see the footage of the crash, it seems amazing that he survived
it, much less that the M2F2 could be rebuilt and flown again.
If I'd been in a aircraft that had started behaving like this, I would
have said "screw this noise" and used the ejection seat:
http://www.youtube.com/watch?v=YCZNW4NrLVY

Pat

On Nov 28, 8:19�pm, "Greg D. Moore \(Strider\)"
wrote:
You really want to go there Bob? �Honestly?

How many B-52s are still in service? �Heck, how many DC-3s?

Do we need to name others?



well how many reusable space vehicles?

B-52s are just reusing the airframe, nearly all other parts have been
relaced over and over,

probably few commercial DC3s since they are fuel piggies.

now think about the launch landing and other stresses shuttle go thru.

now other vehicle goes thru such a challenging environment

Pat Flannery wrote:
You wouldn't have thought that the extra fin (particularly in that
position where there wouldn't have been that much airflow over it during
the final approach) really would have changed things that much, but
that's just what I read about it also.
The M2F2 crash was covered on the national nightly news the day it
occurred, and the radio communications between the aircraft and the
ground suggested that Bruce Peterson was very concerned that a
helicopter had gotten into his glide path and he was going to collide
with it ("That chopper's gonna get me!" he said twice during the final
approach, although the ground assured him there was no collision danger).
When you see the footage of the crash, it seems amazing that he survived
it, much less that the M2F2 could be rebuilt and flown again.
If I'd been in a aircraft that had started behaving like this, I would
have said "screw this noise" and used the ejectio
seat:http://www.youtube.com/watch?v=YCZNW4NrLVY


I hope that everyone doesn't think when they see a video on youtube
( or wherever ) of an M2-F2 in PIO that it's the infamous Bruce
Peterson crash. In fact I think the link you provided shows film
footage of one of the earlier flights with Milt Thompson at the
controls.

But wow ... you can really see that thing not only oscillating from
side to side ... but also pulling G's from one turn to the next. Some
of those early M2-F2 flights, they actually put the thing into PIO on
purpose to study the problem.

I read somewhere that Milt Thompson ( in this film footage I think )
was actually turning a yaw damper knob ( or some similar control
device ) to smooth out the oscillations ... but he actually turned the
knob the wrong way ! So the control inputs were making the PIO even
worse ! However ... he still made a successful landing.

Oh yeah ... by the way. When I was a little kid ... and I was
watching the " Six million dollar man " ... my Dad liked to point out
that he heard the same voice communications you heard on the t.v. news
that Bruce Peterson had with ground control before his crash. My dad
said that the guy was " screaming his head off ". Although I've never
heard that recording myself.


Chris

Pat Flannery wrote:
Reunite Gondwanaland (Mary Shafer) wrote:
No. *The M2-F2 was dangerous because of the lateral "phugoid". *It
really had to be flown feet-on-the-floor. *Check out "Runway to Orbit"
for more detail. *The HL-10 was okay.
No it was not, at least as originally built


You know ... there's something funny about pointing out that flying a
particular model of a lifting body as " dangerous ".

A test pilot straps himself into a craft that has the flying
characteristics of both a brick and a bathtub. It's got a rocket
engine ( on powered flights ) that uses liquid oxygen and ethyl
alcohol as fuel ... essentially a flying bomb if something goes
wrong. On an unpowered flight your dropped from a pylon out on the
wing of a B-52 from 45,000 feet ... and have about three and a half
minutes before touchdown. So your rate of decent is like 13,000 feet
per minute. ( Dive bomb the lake bed ! ) Maneuver your flying potato
towards the runway. Flare the thing at around 300 knots. Pop the
gear down at the last second ... and touchdown at a little bit below
200 knots. Then coast to a stop a mile and half down the lake bed.

Where is the no desk ?

=]

Chris

CCBlack wrote:
Pat Flannery wrote:
You wouldn't have thought that the extra fin (particularly in that
position where there wouldn't have been that much airflow over it during
the final approach) really would have changed things that much, but
that's just what I read about it also.
The M2F2 crash was covered on the national nightly news the day it
occurred, and the radio communications between the aircraft and the
ground suggested that Bruce Peterson was very concerned that a
helicopter had gotten into his glide path and he was going to collide
with it ("That chopper's gonna get me!" he said twice during the final
approach, although the ground assured him there was no collision danger).
When you see the footage of the crash, it seems amazing that he survived
it, much less that the M2F2 could be rebuilt and flown again.
If I'd been in a aircraft that had started behaving like this, I would
have said "screw this noise" and used the ejectio
seat:http://www.youtube.com/watch?v=YCZNW4NrLVY


I hope that everyone doesn't think when they see a video on youtube
( or wherever ) of an M2-F2 in PIO that it's the infamous Bruce
Peterson crash. In fact I think the link you provided shows film
footage of one of the earlier flights with Milt Thompson at the
controls.

But wow ... you can really see that thing not only oscillating from
side to side ... but also pulling G's from one turn to the next. Some
of those early M2-F2 flights, they actually put the thing into PIO on
purpose to study the problem.

It was obvious that it had a real roll stability problem, I suspect from
the fact that the vertical fins wouldn't get into the airstream enough
to be able to correct the roll to either side until it got so severe
that the aircraft was almost at a 90 degree angle from vertical.
It's funny that that trait didn't show up in wind tunnel tests of models
of the design. They may have thought it would be okay from the test
flights of the M2F1, but that had a set of horizontal fins on it the
M2F2 lacked. They were probably considered unworkable from a reentry
viewpoint if the aircraft had been developed into a orbital version.
BTW, when I was looking around for info on the HL-10, I ran into this:
http://en.wikipedia.org/wiki/Northrop_HL-10
Which describes plans to launch a pair of reentry capable HL-10s and
Apollo CSMs into space atop Saturn Vs.
I would think that the bubble nose would have to be deleted in that
version in favor of a more conventional cockpit.
Asking for two Saturn V's for this concept was probably a bit much; if
they had asked for a couple of Saturn 1B's or Titan III's and skipped
the Apollo CSM they might have gotten somewhere on it, although all they
would have effectively done is reinvent the X-20 Dynasoar.



I read somewhere that Milt Thompson ( in this film footage I think )
was actually turning a yaw damper knob ( or some similar control
device ) to smooth out the oscillations ... but he actually turned the
knob the wrong way ! So the control inputs were making the PIO even
worse ! However ... he still made a successful landing.

That sounds like the description from Milt Thompson's book "Flying
Without Wings" which he unfortunately died before finishing, so the book
had to be finished from his notes, and the quality really suffered as a
result.


Oh yeah ... by the way. When I was a little kid ... and I was
watching the " Six million dollar man " ... my Dad liked to point out
that he heard the same voice communications you heard on the t.v. news
that Bruce Peterson had with ground control before his crash. My dad
said that the guy was " screaming his head off ". Although I've never
heard that recording myself.

He was obviously very excited and seemed fixated on the helicopter.
I can see the source of the helicopter concern, as with no way to
accurately judge the distance to it, you could think that it was
hovering right in your glidepath, while observers at a distance would be
able to see that you were going to miss it.
It probably shouldn't have been flying directly over the landing path in
any case, as the last thing a pilot attempting a glide landing needs is
any sort of distraction, particularly in a aircraft that has as high of
a sink rate as the M2F2.

Pat

CCBlack wrote:

A test pilot straps himself into a craft that has the flying
characteristics of both a brick and a bathtub. It's got a rocket
engine ( on powered flights ) that uses liquid oxygen and ethyl
alcohol as fuel ... essentially a flying bomb if something goes
wrong. On an unpowered flight your dropped from a pylon out on the
wing of a B-52 from 45,000 feet ... and have about three and a half
minutes before touchdown. So your rate of decent is like 13,000 feet
per minute. ( Dive bomb the lake bed ! ) Maneuver your flying potato
towards the runway. Flare the thing at around 300 knots. Pop the
gear down at the last second ... and touchdown at a little bit below
200 knots. Then coast to a stop a mile and half down the lake bed.


Could be worse...you could be flying a Yokosuka MXY-7 Ohka. :-D

Pat

On Nov 29, 9:56*am, Pat Flannery wrote:
CCBlack wrote:
Pat Flannery wrote:
You wouldn't have thought that the extra fin (particularly in that
position where there wouldn't have been that much airflow over it during
the final approach) really would have changed things that much, but
that's just what I read about it also.
The M2F2 crash was covered on the national nightly news the day it
occurred, and the radio communications between the aircraft and the
ground suggested that Bruce Peterson was very concerned that a
helicopter had gotten into his glide path and he was going to collide
with it ("That chopper's gonna get me!" he said twice during the final
approach, although the ground assured him there was no collision danger).
When you see the footage of the crash, it seems amazing that he survived
it, much less that the M2F2 could be rebuilt and flown again.
If I'd been in a aircraft that had started behaving like this, I would
have said "screw this noise" and used the ejectio
seat:http://www.youtube.com/watch?v=YCZNW4NrLVY

I hope that everyone doesn't think when they see a video on youtube
( or wherever ) of an M2-F2 in PIO that it's the infamous Bruce
Peterson crash. *In fact I think the link you provided shows film
footage of one of the earlier flights with Milt Thompson at the
controls.

But wow ... you can really see that thing not only oscillating from
side to side ... but also pulling G's from one turn to the next. *Some
of those early M2-F2 flights, they actually put the thing into PIO on
purpose to study the problem.

It was obvious that it had a real roll stability problem, I suspect from
the fact that the vertical fins wouldn't get into the airstream enough
to be able to correct the roll to either side until it got so severe
that the aircraft was almost at a 90 degree angle from vertical.
It's funny that that trait didn't show up in wind tunnel tests of models
of the design. They may have thought it would be okay from the test
flights of the M2F1, but that had a set of horizontal fins on it the
M2F2 lacked. They were probably considered unworkable from a reentry
viewpoint if the aircraft had been developed into a orbital version.
BTW, when I was looking around for info on the HL-10, I ran into this:http://en.wikipedia.org/wiki/Northrop_HL-10
Which describes plans to launch a pair of reentry capable HL-10s and
Apollo CSMs into space atop Saturn Vs.
I would think that the bubble nose would have to be deleted in that
version in favor of a more conventional cockpit.
Asking for two Saturn V's for this concept was probably a bit much; if
they had asked for a couple of Saturn 1B's or Titan III's and skipped
the Apollo CSM they might have gotten somewhere on it, although all they
would have effectively done is reinvent the X-20 Dynasoar.



I read somewhere that Milt Thompson ( in this film footage I think )
was actually turning a yaw damper knob ( or some similar control
device ) to smooth out the oscillations ... but he actually turned the
knob the wrong way ! *So the control inputs were making the PIO even
worse ! *However ... he still made a successful landing.

That sounds like the description from Milt Thompson's book "Flying
Without Wings" which he unfortunately died before finishing, so the book
had to be finished from his notes, and the quality really suffered as a
result.



Oh yeah ... by the way. *When I was a little kid ... and I was
watching the " Six million dollar man " *... my Dad liked to point out
that he heard the same voice communications you heard on the t.v. news
that Bruce Peterson had with ground control before his crash. *My dad
said that the guy was " screaming his head off ". *Although I've never
heard that recording myself.

He was obviously very excited and seemed fixated on the helicopter.
I can see the source of the helicopter concern, as with no way to
accurately judge the distance to it, you could think that it was
hovering right in your glidepath, while observers at a distance would be
able to see that you were going to miss it.
It probably shouldn't have been flying directly over the landing path in
any case, as the last thing a pilot attempting a glide landing needs is
any sort of distraction, particularly in a aircraft that has as high of
a sink rate as the M2F2.

Pat- Hide quoted text -

- Show quoted text -


If I'm not mistaken it wasn't the helicopter that was in the way, or
in front of the runway ... it was that Peterson was off course after
trying to recover from PIO. When he got the thing in a relative
stable flying condition ... he wasn't going to make the intended
runway landing. He was headed off into a part of the lakebed that was
unmarked. The helicopter was actually probably where is was supposed
to be ... but Peterson was headed right at it. So then he was
distracted by the helicopter ... and had no visual reference markings
on the lake bed to judge his distance off of the lake bed.

Well ... anyway ... some pilot lingo jargon like that. I think he
screwed the pooch to be honest.

Hey ... why in the heck hasn't " Six million Dollar Man " been
released in North America on DVD yet ? Man ... I may be a geek ...
but I loved that show. I noticed it's been released in Europe.
Darnit.

=[


Chris