Keys to flying in ground effect:

[durabol[_2_]]

Keys to flying in ground effect:

-want sensitive control so can react quickly to "squirelyness"
-large stabilizer (perhaps a stabilator) and longish tail boom
-optimized control surfaces for good control at low speed
-best to fly only in low wind
-long tow rope to avoid turbulence of or crashing into boat

-anything missing?

Brock

[vaughn[_2_]]

"durabol" > wrote in message
...
> Keys to flying in ground effect:
>
> -want sensitive control so can react quickly to "squirelyness"

....which will quickly lead to a PIO, given an inexperienced pilot. I don't know
exactly what you are planning, but go to a gliderport and get some aero tow
experience before you go any further.

> -anything missing?

I don't know exactly what you are planning, but I earnestly suggest that you go
to a gliderport and get some aero tow experience before you go any further.
http://www.ssa.org/sport/wheretofly.asp


Vaughn

[Wayne Paul]

"vaughn" > wrote in message ...
>
> "durabol" > wrote in message
> ...
>> Keys to flying in ground effect:
>>
>> -want sensitive control so can react quickly to "squirelyness"
>
> ...which will quickly lead to a PIO, given an inexperienced pilot. I don't know
> exactly what you are planning, but go to a gliderport and get some aero tow
> experience before you go any further.
>
>> -anything missing?
>
> I don't know exactly what you are planning, but I earnestly suggest that you go
> to a gliderport and get some aero tow experience before you go any further.
> http://www.ssa.org/sport/wheretofly.asp
>
>
> Vaughn

I totally agree with Vaughns. Sensitive controls with quick reaction is very likely to lead to over-reaction. In the initial part of a glider aero tow, when the glider is airborne and the tow plane isn't, you will rapidly learn what is like to fly in ground effect.

As a side note: You may even find flying gliders fun!!

Wayne
http://www.soaridaho.com/

[bildan]

On Nov 25, 6:19*am, "vaughn" >
wrote:
> "durabol" > wrote in message
>
> ...
>
> > Keys to flying in ground effect:
>
> > -want sensitive control so can react quickly to "squirelyness"
>
> ...which will quickly lead to a PIO, given an inexperienced pilot. *I don't know
> exactly what you are planning, but go to a gliderport and get some aero tow
> experience before you go any further.
>
> > -anything missing?
>
> I don't know exactly what you are planning, but I earnestly suggest that you go
> to a gliderport and get some aero tow experience before you go any further.http://www.ssa.org/sport/wheretofly.asp
>
> Vaughn

I strongly agree with Vaughn - learn aero tow first. It's not
trivial.

If possible, fly a Grob 103 in ground effect. It has an interesting
behavior that illustrates some of the issues. Mainly, the center of
lift moves forward in ground effect reducing pitch stability and
making the elevator about twice as sensitive as it is out of ground
effect.

Most existing G103's have been damaged at least once due to PIO's in
ground effect - although some of this is due to a peculiar wheel
bounce effect.

[cavelamb[_2_]]

durabol wrote:
> Keys to flying in ground effect:
>
> -want sensitive control so can react quickly to "squirelyness"
> -large stabilizer (perhaps a stabilator) and longish tail boom
> -optimized control surfaces for good control at low speed
> -best to fly only in low wind
> -long tow rope to avoid turbulence of or crashing into boat
>
> -anything missing?
>
> Brock

We all start learning somewhere... So yes, there is quite a bit missing.

First and foremost - learn how to do center of gravity calculations
and how to find the center of pressure (Lift) of your wing and tail surfaces.

Then, learn about the relationship between CG and the center of lift and
how that relationship determines stability. A forward CG will give you
that "squirleyness". Correcting the CG/CP relationship will correct it.

A large tail area and long tail arm won't fix instability.

Flying in low wind for sure, but which way???
Which way do the birds fly?


The tow rope could be an interesting problem that could actually be dangerous.
Two parts -

1) where the rope attaches to the aircraft? Will that impart a pitch moment?

2) Jerk. (4th derivative of motion) What happens when the rope suddenly
goes taught? What about if that happens in flight?

[Oliver Arend]

>*A forward CG will give you that "squirleyness". *Correcting the CG/CP relationship will correct it.

You mean "a forward CP", so the distance between CG and CP will be
shorter!?

> A large tail area and long tail arm won't fix instability.

That's contrary to what I learned, so please explain further.

Oliver

[Brian Whatcott]

Oliver Arend wrote:
>> A forward CG will give you that "squirleyness". Correcting the CG/CP relationship will correct it.
>
> You mean "a forward CP", so the distance between CG and CP will be
> shorter!?
>
>> A large tail area and long tail arm won't fix instability.
>
> That's contrary to what I learned, so please explain further.
>
> Oliver

Increased 'tail volume' as it's sometimes called, can promote dutch roll....

Brian W

[cavelamb[_2_]]

Oliver Arend wrote:
>> A forward CG will give you that "squirleyness". Correcting the CG/CP relationship will correct it.
>
> You mean "a forward CP", so the distance between CG and CP will be
> shorter!?

Sorry, you are right. That would be an an AFT CG problem.

CG is ahead of CP by some distance, and a download on the tail
holds the nose up.

>
>> A large tail area and long tail arm won't fix instability.
>
> That's contrary to what I learned, so please explain further.
>
> Oliver


Stability is a CG/CP issue.

[Anyolmouse]

"durabol" > wrote in message
...
> Keys to flying in ground effect:
>
> -want sensitive control so can react quickly to "squirelyness"
> -large stabilizer (perhaps a stabilator) and longish tail boom
> -optimized control surfaces for good control at low speed
> -best to fly only in low wind
> -long tow rope to avoid turbulence of or crashing into boat
>
> -anything missing?
>
> Brock

Some reading for you-
http://www.angelfire.com/on/dragonflyaircraft/centeroflift.html There
are what appears to be some typos in it and he also states that the
stall (of the wing) is because of low airspeed. Hmm! I was taught that
it was caused by too much angle of attack. But, some good info in this
page in my opinion.

--
We have met the enemy and he is us-- Pogo

Anyolmouse