BD-5 crash in Australia

In a previous article, "Richard Isakson" said:
bottom of the airplane, the pilots center of gravity is low and the engine
is fairly low. That makes the airplane center of gravity low but the thrust
line is up at that top of the airplane. The high thrust line wants to push
the nose down so the pilot has to compensate with aft stick. Now the engine
stops. The clutch disengages the engine and the prop and the prop sits out
there windmilling. A windmilling prop is like a parachute, now trying to
pull the nose up. The airplane controls are commanding nose up already so,
between the controls and the prop, up the nose goes. If the pilot's not
spring loaded to shove the nose down, it won't go down. It will pitch up
violently and the g-loading will go up. This causes the wing skins to

The Lake Amphibian, and probably most boat-hull type amphibs, have that
same problem. The weight and drag are down near the hull, and the thrust
comes from that engine mounted on a pylon above.


--
Paul Tomblin http://blog.xcski.com/
If I have pinged farther than others, it is because I routed upon
the T3s of giants.
-- Greg Andrews

Funny, I've noticed over the years that for the most part the more a
person
or group calls on God, the more they love their enemy dead.



True for some religions, but not all.


That'd surprise the hell outta all the people who have been burned at the
stake, drowned, hanged, killed in war, etc


"It is true that any sect, cult, or religion will legislate its creed into
law if it acquires the political power to do so, and will follow it by
suppressing opposition, subverting all education to seize early the minds of
the young, and by killing, locking up, or driving underground all heretics."

--- Robert A. Heinlein

"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

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

Dan Nafe wrote:

Funny, I've noticed over the years that for the most part the more a person
or group calls on God, the more they love their enemy dead.







True for some religions, but not all.

OK, name 'em....


You cannot get "we want you dead" out of either book.

You miss the point entirely.

Books, like guns...
Don't kill people.
People/groups with the books [and guns], kill people.

Settlers came to America from England to avoid religious persecution
and then burned witches at the stake when they were in charge.
This kinda' trade mark crap has been going on since the Stone Age.

- Barnyard BOb -

In article ,
"Ron Webb" wrote:

Funny, I've noticed over the years that for the most part the more a
person
or group calls on God, the more they love their enemy dead.



True for some religions, but not all.


That'd surprise the hell outta all the people who have been burned at the
stake, drowned, hanged, killed in war, etc


"It is true that any sect, cult, or religion will legislate its creed into
law if it acquires the political power to do so, and will follow it by
suppressing opposition, subverting all education to seize early the minds of
the young, and by killing, locking up, or driving underground all heretics."

--- Robert A. Heinlein

Someone once said that the preachers promise heaven until they attain
control; then, all they deliver is hell. IMHO, this appears to be true
of all religions.

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

Orval Fairbairn wrote:
In article ,
"Ron Webb" wrote:

Funny, I've noticed over the years that for the most part the more a
person
or group calls on God, the more they love their enemy dead.


True for some religions, but not all.

That'd surprise the hell outta all the people who have been burned at the
stake, drowned, hanged, killed in war, etc


"It is true that any sect, cult, or religion will legislate its creed into
law if it acquires the political power to do so, and will follow it by
suppressing opposition, subverting all education to seize early the minds of
the young, and by killing, locking up, or driving underground all heretics."

--- Robert A. Heinlein

Someone once said that the preachers promise heaven until they attain
control; then, all they deliver is hell. IMHO, this appears to be true
of all religions.

And ex wives

Dan, U.S. Air Force, retired

"Dan" wrote in message
...
Orval Fairbairn wrote:
In article ,
"Ron Webb" wrote:

Funny, I've noticed over the years that for the most part the more a
person
or group calls on God, the more they love their enemy dead.


True for some religions, but not all.

That'd surprise the hell outta all the people who have been burned at
the stake, drowned, hanged, killed in war, etc


"It is true that any sect, cult, or religion will legislate its creed
into law if it acquires the political power to do so, and will follow it
by suppressing opposition, subverting all education to seize early the
minds of the young, and by killing, locking up, or driving underground
all heretics."

--- Robert A. Heinlein

Someone once said that the preachers promise heaven until they attain
control; then, all they deliver is hell. IMHO, this appears to be true of
all religions.

And ex wives


And they don't always have to be ex wives.

In a previous article, Richard Riley said:
On Wed, 23 May 2007 19:09:31 -0300, "Dave"
wrote:
In Christianity, the believers are told to love their enemy, (not that the
atheist is an enemy) and pray for non believers. That is what they are
doing.
Funny, I've noticed over the years that for the most part the more a person
or group calls on God, the more they love their enemy dead.


Have you ever met a Buddhist?

Obviously you never have.

Buddhists don't call on god. They don't have a god.

--
Paul Tomblin http://blog.xcski.com/
Software planning seems to be based on denying plausibility.
-- Graham Reed