Glider crow-hops:

Brad:

Thanks for all the info about flying the Apis. I'm getting closer to the first flights, probably preceded by some simple ground towed crow-hops to get used to it first.

A question:

Did your Apis have flaperon/wing gap seals? Mine had them, but they made the force on the stick in the roll direction very hard and sticky, at least on the ground.

The maintenance log for my Apis shows them only recently installed and with only about 3 flights on them, so I doubt they were well tested.

It seemed like not a good idea to have hard moving and sticky roll control, at least on the first flights, so I took them off of my Apis. It vastly reduced the stick force required to move the flaperons, and made it more like the elevator force.

I could replace them with new if required. What do you think?

Thanks,
Jerry Booker

On Aug 29, 6:21*am, J-Soar wrote:
Brad:

Thanks for all the info about flying the Apis. I'm getting closer to the first flights, probably preceded by some simple ground towed crow-hops to get used to it first.

A question:

Did your Apis have flaperon/wing gap seals? Mine had them, but they made the force on the stick in the roll direction very hard and sticky, at least on the ground.

The maintenance log for my Apis shows them only recently installed and with only about 3 flights on them, so I doubt they were well tested.

It seemed like not a good idea to have hard moving and sticky roll control, at least on the first flights, so I took them off of my Apis. It vastly reduced the stick force required to move the flaperons, and made it more like the elevator force.

I could replace them with new if required. What do you think?

Thanks,
Jerry Booker

Hi Jerry,

Robert was very conscious about trying to get the most performance out
of the Apis, that is why he installed those root fences. Mine did not
have them and removing yours already gives you a stick force
reduction, I would just leave them off. My Apis had light roll forces.

You probably don't need to do a crow hop, but if you do remember this
is a VERY LIGHT sailplane and will want to jump off the ground rather
quickly............put trim full forward!

Brad

I put the flaperon root flow fences on my APIS as well. I also have mylar
gap seal on the lower surface only, plus some interior "V" seal along the
top and bottom of the flaperons.

I've never flown the plane without the flow fences. If the seal strip
(fuzzy piece of velcro) is narrow and the flow fence is waxed, then these
add very little to the control forces. However, when I added the gap seals,
I did notice an increase in force at the stick to move the flaperons. While
this is noticeable on the ground, I've never really been aware of it in
flight.

FWIW.

John Scott

Thanks Brad and John.

I should have been more descriptive. I was referring to the mylar gap seals that cover the joint between the aft edge of the wing and the flaperon. The flow fences at the root didn't seem to be a problem, so I have left them on. I just removed the mylar seals, and got much less resistance to the stick movements.

I wanted to make sure it was safe to fly without them for the first flights.. I know they probably help with gliding performance, so I will later probably follow some good advice in a direct email and just install them on the bottom surface.

Thanks again,
Jerry Booker

On Aug 30, 6:01*pm, J-Soar wrote:
Thanks Brad and John.

I should have been more descriptive. I was referring to the mylar gap seals that cover the joint between the aft edge of the wing and the flaperon. The flow fences at the root didn't seem to be a problem, so I have left them on. I just removed the mylar seals, and got much less resistance to the stick movements.

I wanted to make sure it was safe to fly without them for the first flights. I know they probably help with gliding performance, so I will later probably follow some good advice in a direct email and just install them on the bottom surface.

Thanks again,
Jerry Booker

So now we're adding up new pilot, new glider, new manuevers (crow-
hops) not practiced with other gliders before, glider not flown by
instructors the pilot can get checked out by, new tow method (ground
not air) and, the latest, uncertain status of mylar seals and other
"improvements" to the control system, so glider flying in unknown and
un-test flown configuration. All at once.

I think enough advice has been dispensed in this thread about useful
approaches to glider test flying, transitions to new gliders, etc.
etc. It doesn't seem to be sinking in though. I hope someone at the
airport where this all is going to happen will perk up.

John Cochrane

That's why "Hey, watch this!" are so famous as the last utterances of so many amateur engineers, scientists, and yes...test pilots.

Hopefully, not in this case.

On Thursday, August 30, 2012 6:38:55 PM UTC-6, John Cochrane wrote:
On Aug 30, 6:01*pm, J-Soar wrote:

Thanks Brad and John.



I should have been more descriptive. I was referring to the mylar gap seals that cover the joint between the aft edge of the wing and the flaperon.. The flow fences at the root didn't seem to be a problem, so I have left them on. I just removed the mylar seals, and got much less resistance to the stick movements.



I wanted to make sure it was safe to fly without them for the first flights. I know they probably help with gliding performance, so I will later probably follow some good advice in a direct email and just install them on the bottom surface.



Thanks again,

Jerry Booker



So now we're adding up new pilot, new glider, new manuevers (crow-

hops) not practiced with other gliders before, glider not flown by

instructors the pilot can get checked out by, new tow method (ground

not air) and, the latest, uncertain status of mylar seals and other

"improvements" to the control system, so glider flying in unknown and

un-test flown configuration. All at once.



I think enough advice has been dispensed in this thread about useful

approaches to glider test flying, transitions to new gliders, etc.

etc. It doesn't seem to be sinking in though. I hope someone at the

airport where this all is going to happen will perk up.



John Cochrane

John, I have deep respect for your views on many subjects, but here you are just plain wrong. All the "issues" you raise above are precisely why this first 'flight' should be a "crow hop". There is exactly zero chance of the pilot getting hurt and virtually no chance of dinging the glider. But, there is an excellent chance of uncovering problems which could prove fatal if an aero tow is attempted.

Despite it being done tens of thousands of time in the whole history of gliding, I don't think there is a single incidence of pilot injury from a minimum energy "crow hop". I have it on excellent authority that no ground launch sign off is needed for a "crow hop" since it really isn't a launch of any kind - just the glider equivalent of taxi tests.

What I find revealing in the hand wringing is an apparent terror of takeoff rolls and landings rolls which is all a "crow hop" is. Maybe you folks need more practice. Go do some "crow hops" and get back to us.

"Newly soloed student pilot...."

Didn't have to read a thing after that to reach the conclusion that any initial test flying should be conducted by someone else, who can give him a proper checkout with specific comments on his particular aircrafts handling qualities and/or quirks when he's more fully capable and has more glider experience. On the pro side of the aviation world, we like to say that if you'll "work it backwards from the FAA/NTSB hearing- you WILL arrive at the right answer" to questions like this.

My 2 cents.

Rob
ZAP

John, I have deep respect for your views on many subjects, but here you are just plain wrong. *All the "issues" you raise above are precisely why this first 'flight' should be a "crow hop". *There is exactly zero chance of the pilot getting hurt and virtually no chance of dinging the glider. *But, there is an excellent chance of uncovering problems which could prove fatal if an aero tow is attempted.

Despite it being done tens of thousands of time in the whole history of gliding, I don't think there is a single incidence of pilot injury from a minimum energy "crow hop". *I have it on excellent authority that no ground launch sign off is needed for a "crow hop" since it really isn't a launch of any kind - just the glider equivalent of taxi tests.

What I find revealing in the hand wringing is an apparent terror of takeoff rolls and landings rolls which is all a "crow hop" is. Maybe you folks need more practice. *Go do some "crow hops" and get back to us.

I have no problem with "crow hops" per se. I'm just applying the
principle of "do one new thing per flight." Add up the number of
"firsts" on this proposed flight. You need two hands.

John Cochrane

I'm with John, and many others who have commented on this thread.

And Bill, I respectfully, but totally, disagree with you.

The "crow hop" idea is seriously flawed in this circumstance, IMO.

Either the glider in question is a safe, known quantity, and therefore is probably a lot easier to fly than any of the trainers J-soar has flown, or it is an unknown quantity that should be test flown by an experienced pilot.

In the first case, there is NFW a crow hop is easier or safer than a normal aero tow. In the second case, the nature of the unknowns would be the determining factor in whether the crow hop approach is needed. Seems unlikely in this case, unless there had been some serious modifications made to the Apis in question.

I'm a bit perplexed as to why J-soar is so hung up on this crow-hop approach to what is really a simple and common exercise. But if I was there, I would do my best to discourage it.

Just sayin'...

Kirk
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