bouncing off the runway

E Z Peaces wrote in
:

Bertie the Bunyip wrote:
More_Flaps wrote in
news:0390ffd1-a85e-4ae3-8971-
:

On Jun 26, 3:00 pm, E Z Peaces wrote:

The man said the problem was that he had failed to keep the stick
back after touchdown. Does his recollection make sense?
Nope



Does actually. Little tailfraggers, and big ones, come to think of
it, bounce along of you dont get the stick back after three pointing.
the mains will thrust it back up into the air a bit and then the nose
comes back down again repeating the cycle.



Bertie

Doesn't a three-point landing occur at stall speed?


Not always.


Isn't the plane
going too slowly to lift off again? Besides, if the tail is that low,
touching down won't increase the angle of attack, will it?

If the tail is that low, you have th estick all the way back.


You say the mains will thrust it back up into the air and the cycle
will repeat. In a three-point landing, it seems it would take springs
to make a plane rise. Aren't shock absorbers supposed to prevent
that?


Shock absorbers are for cars and they'r emade to dampen cycles such as
that.




Bertie

Bertie the Bunyip wrote:
E Z Peaces wrote in
:

Bertie the Bunyip wrote:
More_Flaps wrote in
news:0390ffd1-a85e-4ae3-8971-
:

On Jun 26, 3:00 pm, E Z Peaces wrote:

The man said the problem was that he had failed to keep the stick
back after touchdown. Does his recollection make sense?
Nope


Does actually. Little tailfraggers, and big ones, come to think of
it, bounce along of you dont get the stick back after three pointing.
the mains will thrust it back up into the air a bit and then the nose
comes back down again repeating the cycle.



Bertie

Doesn't a three-point landing occur at stall speed?


Not always.


Isn't the plane
going too slowly to lift off again? Besides, if the tail is that low,
touching down won't increase the angle of attack, will it?

If the tail is that low, you have th estick all the way back.

The man said it was after touchdown that he'd quit holding the stick back.

You say the mains will thrust it back up into the air and the cycle
will repeat. In a three-point landing, it seems it would take springs
to make a plane rise. Aren't shock absorbers supposed to prevent
that?


Shock absorbers are for cars and they'r emade to dampen cycles such as
that.




Bertie

I've read about oleo aircraft struts at least as early as the 1920s.

Sorry about my multiple posts this morning. Each time I sent it, my
newsreader said the news server had not responded, so I'd try again.

E Z Peaces wrote in
:

Bertie the Bunyip wrote:
E Z Peaces wrote in
:

Bertie the Bunyip wrote:
More_Flaps wrote in
news:0390ffd1-a85e-4ae3-8971-
:

On Jun 26, 3:00 pm, E Z Peaces wrote:

The man said the problem was that he had failed to keep the stick
back after touchdown. Does his recollection make sense?
Nope


Does actually. Little tailfraggers, and big ones, come to think of
it, bounce along of you dont get the stick back after three
pointing. the mains will thrust it back up into the air a bit and
then the nose comes back down again repeating the cycle.



Bertie

Doesn't a three-point landing occur at stall speed?


Not always.


Isn't the plane
going too slowly to lift off again? Besides, if the tail is that
low, touching down won't increase the angle of attack, will it?

If the tail is that low, you have th estick all the way back.

The man said it was after touchdown that he'd quit holding the stick
back.



Yes, I know. I read your post.



You say the mains will thrust it back up into the air and the cycle
will repeat. In a three-point landing, it seems it would take
springs to make a plane rise. Aren't shock absorbers supposed to
prevent that?


Shock absorbers are for cars and they'r emade to dampen cycles such
as that.




Bertie

I've read about oleo aircraft struts at least as early as the 1920s.

Theyre not dampers, they're oleos and provide no damping. Shock
absorbers are something different and have a different function, though
tey're misnamed in any case, since its the springs that absorb and the
shicks, as they;'re called, prevent the energy stored in the spring from
rebounding the wheel off the road. Airplanes don't have shock absorbers.

Bertie the Bunyip wrote:
E Z Peaces wrote in
:


I've read about oleo aircraft struts at least as early as the 1920s.

Theyre not dampers, they're oleos and provide no damping. Shock
absorbers are something different and have a different function, though
tey're misnamed in any case, since its the springs that absorb and the
shicks, as they;'re called, prevent the energy stored in the spring from
rebounding the wheel off the road. Airplanes don't have shock absorbers.

Here's an example:
http://www.hangar9aeroworks.com/Aero...oncastrut.html

E Z Peaces wrote in
:

Bertie the Bunyip wrote:
E Z Peaces wrote in
:


I've read about oleo aircraft struts at least as early as the 1920s.

Theyre not dampers, they're oleos and provide no damping. Shock
absorbers are something different and have a different function,
though tey're misnamed in any case, since its the springs that absorb
and the shicks, as they;'re called, prevent the energy stored in the
spring from rebounding the wheel off the road. Airplanes don't have
shock absorbers.

Here's an example:
http://www.hangar9aeroworks.com/Aero...oncastrut.html


Yeah, I know,. I was flying one a couple of days ago and I've had them
apart, too.
It does little or nothing to stop a bounce in spite of it's name. I can
also stater that categorically since I was training two ab-initio tailwheel
pilots in it.




Bertie

Bertie the Bunyip wrote:
E Z Peaces wrote in
:

Bertie the Bunyip wrote:
E Z Peaces wrote in
:

I've read about oleo aircraft struts at least as early as the 1920s.
Theyre not dampers, they're oleos and provide no damping. Shock
absorbers are something different and have a different function,
though tey're misnamed in any case, since its the springs that absorb
and the shicks, as they;'re called, prevent the energy stored in the
spring from rebounding the wheel off the road. Airplanes don't have
shock absorbers.
Here's an example:
http://www.hangar9aeroworks.com/Aero...oncastrut.html


Yeah, I know,. I was flying one a couple of days ago and I've had them
apart, too.
It does little or nothing to stop a bounce in spite of it's name. I can
also stater that categorically since I was training two ab-initio tailwheel
pilots in it.

Have you stood by the wing tip and rocked the wing like a seesaw? If
you can get it to rock higher and higher and it keeps rocking after you
let go, then I guess the landing gear doesn't have effective shock
absorbers.

I remember touchdown bounces from my days with balsa, tissue and dope.
None of my models would have bounced even slightly from a stationary
drop because all had rigid landing gear.

None had a movable elevator. I could climb and dive by changing thrust,
which would move the center of lift by slightly changing the speed. If
I wanted a plane to fly faster, I would move the center of gravity by
weighting the nose so the model would balance at a higher speed.

Without elevator control I couldn't make three-point landings. My
Curtis Hawk had the biggest bounce, but the airspeed was low enough that
it would rise only about five inches before mushing elegantly to the
ground. My Corsair would bounce about two inches.

My Spitfire landed much faster than the others because I weighted the
nose with two flashlight batteries. With that much airspeed, it might
have risen disastrously high if it had bounced on touchdown. It didn't
bounce at all.

The three models were different in the position of the main gear. The
wheels of the Hawk were well forward of the center of gravity;
apparently the Army plane was designed that way to counter the tendency
of a short, high plane to nose over when landing on a rough field at low
speed. When the wheels of my model touched down, the center of mass
would continue to fall, lowering the tail and increasing the angle of
attack. Naturally, it bounced.

The problem wasn't as bad with the Corsair because the wheels weren't so
far forward. The wheels of the Spitfire were farther back, and the
weights brought the center of gravity forward as well as increasing
inertia about the horizontal axis. This way, the tail didn't sink fast
enough for the plane to lift off after touchdown.

With my balsa models, bouncing came from the rapid sinking of the tail
after touchdown. If I'd had elevator control, I might have managed
three-point landings with the Hawk. I don't see how the model could
have bounced in that case. (A neighbor used to fly his father's
Stearman under his brother's instruction. He says he sometimes touched
down tail first.)

E Z Peaces wrote in
:

Bertie the Bunyip wrote:
E Z Peaces wrote in
:

Bertie the Bunyip wrote:
E Z Peaces wrote in
:

I've read about oleo aircraft struts at least as early as the
1920s.
Theyre not dampers, they're oleos and provide no damping. Shock
absorbers are something different and have a different function,
though tey're misnamed in any case, since its the springs that
absorb and the shicks, as they;'re called, prevent the energy
stored in the spring from rebounding the wheel off the road.
Airplanes don't have shock absorbers.
Here's an example:
http://www.hangar9aeroworks.com/Aero...oncastrut.html


Yeah, I know,. I was flying one a couple of days ago and I've had
them apart, too.
It does little or nothing to stop a bounce in spite of it's name. I
can also stater that categorically since I was training two ab-initio
tailwheel pilots in it.

Have you stood by the wing tip and rocked the wing like a seesaw? If
you can get it to rock higher and higher and it keeps rocking after
you let go, then I guess the landing gear doesn't have effective shock
absorbers.

I remember touchdown bounces from my days with balsa, tissue and dope.
None of my models would have bounced even slightly from a stationary
drop because all had rigid landing gear.

None had a movable elevator. I could climb and dive by changing
thrust, which would move the center of lift by slightly changing the
speed. If I wanted a plane to fly faster, I would move the center of
gravity by weighting the nose so the model would balance at a higher
speed.

Without elevator control I couldn't make three-point landings. My
Curtis Hawk had the biggest bounce, but the airspeed was low enough
that it would rise only about five inches before mushing elegantly to
the ground. My Corsair would bounce about two inches.

My Spitfire landed much faster than the others because I weighted the
nose with two flashlight batteries. With that much airspeed, it might
have risen disastrously high if it had bounced on touchdown. It
didn't bounce at all.

The three models were different in the position of the main gear. The
wheels of the Hawk were well forward of the center of gravity;
apparently the Army plane was designed that way to counter the
tendency of a short, high plane to nose over when landing on a rough
field at low speed. When the wheels of my model touched down, the
center of mass would continue to fall, lowering the tail and
increasing the angle of attack. Naturally, it bounced.

The problem wasn't as bad with the Corsair because the wheels weren't
so far forward. The wheels of the Spitfire were farther back, and the
weights brought the center of gravity forward as well as increasing
inertia about the horizontal axis. This way, the tail didn't sink
fast enough for the plane to lift off after touchdown.

With my balsa models, bouncing came from the rapid sinking of the tail
after touchdown. If I'd had elevator control, I might have managed
three-point landings with the Hawk. I don't see how the model could
have bounced in that case. (A neighbor used to fly his father's
Stearman under his brother's instruction. He says he sometimes
touched down tail first.)



Wonderful, you should write a book.

Bertie