bouncing off the runway

Yesterday I chatted with a retired man flying a model airplane. He said
he'd taken lessons in a plane with conventional gear in the 1950s. On
his third lesson, the instructor had him land. It was perfect.

After that, every time he landed he would bounce and float above the
runway. His instructor didn't know what caused it. A senior instructor
went up with him and observed that when he touched down, he didn't
continue to hold the stick back. That caused the tail to rise and the
plane to lift off.

That doesn't make sense to me. I've always understood that with
conventional gear, excess speed is the cause of bouncing and floating.
With the main wheels forward of the center of mass, your angle of attack
will increase when you touch down, and the plane will rise if you still
have flying speed.

If a pilot touches down too fast, I've understood that he needs to keep
the tail up and use the brakes without nosing over.

If the instructor had told him he was touching down too fast because he
wasn't holding the stick back far enough during descent, that would make
sense to me because a higher angle of attack induces more drag.

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

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

Cheers

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

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? 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?

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?

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.

On Jun 26, 7:25*am, E Z Peaces wrote:

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

That is one of the biggest myths in aviation. I've flown a lot of
taildraggers (GA) and few of them had the stall angle and the 3 pt
angle in alignment. As an example the Globe Swift stalls with the tail
about 2 feet off the ground while the Decathlon/Citabria stalls with
the tail on the ground and the mains still several feet in the air,
its very, very much still flying in the 3pt position. The hard part of
landing a Citabria is not to crush the mains after landing the tail.

-Robert, CFII

"Robert M. Gary" wrote in news:bc1da0d3-1801-4602-8a5b-
:

On Jun 26, 7:25*am, E Z Peaces wrote:

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

That is one of the biggest myths in aviation. I've flown a lot of
taildraggers (GA) and few of them had the stall angle and the 3 pt
angle in alignment. As an example the Globe Swift stalls with the tail
about 2 feet off the ground while the Decathlon/Citabria stalls with
the tail on the ground and the mains still several feet in the air,
its very, very much still flying in the 3pt position. The hard part of
landing a Citabria is not to crush the mains after landing the tail.

You're right about the Citabria, but not the Swift. The Swift's thing, like
a lot of low wing airplanes, is that the stab gets into roiled air as it
gets near the stall. As further evidence, the alpha on a swift in three
point is about 10 Degrees, no way you're going to have a critical angle
that low on anything this side of a razor blade.


Bertie

On Jun 26, 11:49*am, "Robert M. Gary" wrote:
On Jun 26, 7:25*am, E Z Peaces wrote:

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

That is one of the biggest myths in aviation. I've flown a lot of
taildraggers (GA) and few of them had the stall angle and the 3 pt
angle in alignment. As an example the Globe Swift stalls with the tail
about 2 feet off the ground while the Decathlon/Citabria stalls with
the tail on the ground and the mains still several feet in the air,
its very, very much still flying in the 3pt position. The hard part of
landing a Citabria is not to crush the mains after landing the tail.

-Robert, CFII

Bull****!

BTW: The tail can rise even after the wing is stalled.

-Robert