the topic of PIO

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the topic of PIO

Postby SamKellner » Sat Dec 12, 2015 2:40 pm

Hawks,

For the newer pilots on the forum, and everyone too,

How to avoid PIO, pilot induced oscillations?

Please comment here and relate any PIO experiences. :wave:
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Re: the topic of PIO

Postby Bill Cummings » Sun Dec 13, 2015 1:09 pm

HOW TO AVOID PIO. (Pilot Induced Oscillation)
A pilot must know that the design of a hang glider is the biggest determining factor in PIO.
Most single surface gliders exhibit way less PIO than double surface gliders.
Gliders with shortened wing (lower) flying wires (for designed anhedral, for greater ease of roll control) are more susceptible to PIO.
Gliders with lengthened wing (lower)flying wires (for designed dihedral, for greater stability of roll) are less susceptible to PIO.
The old saying, "Speed is your friend," is no longer always true with modern double surface super ships. Slowing down will dampen PIO.
Some pilots have found that different methods of towing produce different rates of PIO while using the same glider.
Gliders with a vertical stabilizer will nearly cure PIO.
When a manufacturer says PIO is the cause of handling problems with their design the problem is more likely Design Induced Oscillation (DIO).
Pilots have stood on their basetube control bars and locked their shoulders into the top of their down tubes to hold themselves stationary. If the glider still "wing walks," "Dutch Rolls," or "zig-zags," all over the place -----IT'S NOT PIO.
Gliders with a vertical stabilizer will nearly cure PIO and DIO.
Next we should discuss pilot control input that will avoid PIO.
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Re: the topic of PIO

Postby SamKellner » Mon Dec 14, 2015 7:56 pm

billcummings wrote:HOW TO AVOID PIO. (Pilot Induced Oscillation)
"wing walks," .


There was, '78, a bunny hill, 25ft., north of San Diego called the Bean Patch. I only went there once. No instructor.

When I transitioned from Seagull 3 to this glider,
004.JPG
early Pearson design
004.JPG (19.34 KiB) Viewed 1066 times


I can remember some wing walking going on. A couple of big steps is all I had time for. Landing was ok. Musta been about level at that point.

A couple of flights on the bunny hill at Little Black and it never gave me any PIO or DIO problems.

Weight shift control is great!

Weight shift out of control is what we want to avoid. :geek:

:wave:
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Re: the topic of PIO

Postby SamKellner » Mon Mar 07, 2016 7:34 am

BobK, At the time, Dec. '15, I thought starting a new topic was the correct thing to do. Maybe these topics should be combined?

And here is more on PIO.

Read what BillC says.

Here's what I think helps. Keep your hands on the basebar in a diagonal position wider than your shoulders

Thus creating opposing TCF for stability :!:
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Re: the topic of PIO

Postby Bob Kuczewski » Tue Mar 08, 2016 11:20 pm

SamKellner wrote:BobK, At the time, Dec. '15, I thought starting a new topic was the correct thing to do. Maybe these topics should be combined?

And here is more on PIO.

Read what BillC says.

Here's what I think helps. Keep your hands on the basebar in a diagonal position wider than your shoulders

Thus creating opposing TCF for stability :!:


TCF makes sense to me!!!

With more and more clubs joining the US Hawks, there's bound to be some duplication of topics. The search feature helps bring them all together. Also, I'm thinking of starting a "Hang Gliding Tips" forum which will be a good place for lots of stuff that currently ends up in Hang Gliding General.

We can combine this topic with the other one if everyone in this topic agrees to them being combined. I'm fine with it either way.

By the way, one of the nice things about clubs sharing a common forum is that there's less duplication. I'll bet that nearly every club forum in the country has their own PIO topic (or topics). Here we may get one or two but probably not many more than that.
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