BD-5 crash in Australia

Peter Dohm wrote:

maybe the hotdog method of achieving liftoff then maintaing low level
horizontal flight and accelerating like hell before climb out is a
better way of flying them.

My disagreement is only with calling it Hot Dogging. What Stealth Pilot
suggested, and called Hot Dogging, was really just a soft field take off
without the soft field. Accelerate in ground effect, retract the wheels as
appropriate, and begin climbing at the normal climb speed. I have read that
the proceedure was strongly advised for some low powered retractables, such
as the early Swifts, to reduce the risks during the early part of the
climb--although that had to do with maintaining a usefull climb angle over
obstacles, rather than a possible loss of power.

Peter
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Peter,

If what was meant by Stealth is as you describe...... establishing
NORMAL climb speed similar to a soft field T.O., I'm with you.

However, if climb out is NOT established at NORMAL
climb speed as soon as practical....

I gotta stick by my original guns. :-)

P.S. All this discussion is rather moot for me,
after reading Rich Isakson's comments.


Barnyard BOb - the devil's in the details

Peter,

If what was meant by Stealth is as you describe...... establishing
NORMAL climb speed similar to a soft field T.O., I'm with you.

However, if climb out is NOT established at NORMAL
climb speed as soon as practical....

I gotta stick by my original guns. :-)

P.S. All this discussion is rather moot for me,
after reading Rich Isakson's comments.


Barnyard BOb - the devil's in the details

I have always thought that the BD5 was a "very cool looking" little
airplane, and it is certainly interesting on how it might have turned out if
the original engineering team had been much more lucky, or possibly
insightfull, in troubleshooting their drive line problems. I also really
think that much of the behavior to which Rich Isakson alludes is more
related to pilot expectation and the relationship between the center of
trust and center of drag than it is to the relationship between the center
of thrust and the center of gravity.

However, in a practical sense, these are really semantic arguments. They
would make a great discussion over a keg of beer; but in the end, I would
never atempt to fly that airplane equipped as described--because I don't
know how to balance it within the weight that the wing can really handle
and, combined with the change in pitching moment from power on to power off,
the damned thing would attempt to kill me.

The bottom line is that we all agree.

Peter

"Peter Dohm" wrote:

I have always thought that the BD5 was a "very cool looking" little
airplane, and it is certainly interesting on how it might have turned out if
the original engineering team had been much more lucky, or possibly
insightfull, in troubleshooting their drive line problems. I also really
think that much of the behavior to which Rich Isakson alludes is more
related to pilot expectation and the relationship between the center of
trust and center of drag than it is to the relationship between the center
of thrust and the center of gravity.

However, in a practical sense, these are really semantic arguments. They
would make a great discussion over a keg of beer; but in the end, I would
never atempt to fly that airplane equipped as described--because I don't
know how to balance it within the weight that the wing can really handle
and, combined with the change in pitching moment from power on to power off,
the damned thing would attempt to kill me.




The bottom line is that we all agree.

Peter
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There is_one_who never agrees with anybody.
Let him, and his BD remain nameless and shunned.


Barnyard BOb

When hang gliding, the only launches I've ever blown were when I let
the AOA get too high. In a horribly underpowered, weightshifting ship
like an hang glider, high AOA is the easiest way to use up that human
1/4 horsepower and stall. The first launch I blew resulted in an
asymetrical stall and I partially spun back into the hill. The second
resulted in a mushing stall and even though I dropped 63' on the take-
off run, I never made it off the ground.

Of course its rather difficult to compare the take off envelope of a
BD-5 to a hang glider, but with respect to the rapid change in AOA ,
thrust/drag angles, and stall speeds, there are some similarities.
Weight slightly forward and nose level equal a low positive AOA and
increasing thrust as gravity takes effect and continues to accelerate
my ship. We're taught to resist the urge to push out (pull up) until
sufficient airspeed is achieved, usually best glide or greater. With
the BD, this would equate to VR, gear up, accelerate to at least best
glide or best climb (dunno which would come first) and then continue
the climbout. Runway length and obsticles considered of course.

Anyone know what the typical takeoff run is for a BD? Would it be a
good idea to drop the gear unpowered? They take less than a second to
deploy.

Just my thoughts from the non-powered end of the envelope.

Harry

Barnyard BOb wrote:
"Peter Dohm" wrote:

I have always thought that the BD5 was a "very cool looking" little
airplane, and it is certainly interesting on how it might have turned out if
the original engineering team had been much more lucky, or possibly
insightfull, in troubleshooting their drive line problems. I also really
think that much of the behavior to which Rich Isakson alludes is more
related to pilot expectation and the relationship between the center of
trust and center of drag than it is to the relationship between the center
of thrust and the center of gravity.

However, in a practical sense, these are really semantic arguments. They
would make a great discussion over a keg of beer; but in the end, I would
never atempt to fly that airplane equipped as described--because I don't
know how to balance it within the weight that the wing can really handle
and, combined with the change in pitching moment from power on to power off,
the damned thing would attempt to kill me.




The bottom line is that we all agree.

Peter
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

There is_one_who never agrees with anybody.
Let him, and his BD remain nameless and shunned.


Barnyard BOb

Let his unholy name remain uninvoked.

Dan, U.S. Air Force, retired