Glider crow-hops:

It's an Apis 13m. Anyone with a web browser can figure that out.

You should be able to network your way to experience with the type and
develop a transition plan with an experienced CFIG. I don't see the
problem.

-Evan / T8

On Aug 23, 8:38*am, John Cochrane
wrote:
On Aug 23, 10:06*am, Brad wrote:









On Aug 23, 7:41*am, Waveguru wrote:

Teaching yourself to ground launch is a bad idea. *Work with an instructor experienced in ground launch and get sighed off first. *There are many things that can go wrong and it’s not as simple as you think. *Have you read about the accident in Cle Elum last year?

Boggs

I've built and test flown 3 sailplanes, one that was our own design.
Each one was initially flight tested by me using the "crow-hop"
method. I would be happy to share with you what my process was and
what was learned from these tests.

You can contact me directly via Bob K thru the hpaircraft website.

Or you can ask the smart guys here who have never built or crow hopped
a sailplane.

Dick Schreder must be spinning in his grave.

Brad

So, let's clarify. "Crow hops" are commonly done by very experienced
pilots, acting as test pilots for new designs or homebuilt aircraft.
They are doing crow hops to establish if the glider is airworthy and
controllable, and following a detailed plan. Most recently, Dick
Butler and Concordia.

"Crow hops" are not advised as a way for pilots to make a transition
to different aircraft types, especially for newer and less experienced
pilots.

The OP didn't tell us what kind of glider he had bought before
starting flying lessons, only that nobody he knew had any flight
experience in type. And he had previous building experience. This
starts to smell of new pilot AND untested glider, a homebuilt or old
project that has been sitting around for many years whose
airworthiness is in question. Needless to say that is a deadly
combination.

John Cochrane

I must have missed the part where he claimed to be a "low time pilot"

here is how I define a crow-hop:

first step is to place the sailplane intake-off position, taxi tow-
plane ahead of sailplane far enough to have the prop wash be effective
for roll control authority and advance throttle.
glider pilot gets to feel the roll response of the glider, leveling
wings and picking up right then left wing.

actual take-off is a normal take off under tow and then a release from
the towplane straight-ahead and land straight ahead. airbrakes not
used the first time, landing gear not cycled. if pilot is comfortable
with this then proceed to next step.

take-off 2, same procedure except dive brakes are used, land straight
ahead.

if pilot is comfortable then either a few more of these are done or a
high tow is taken.

I would be interested in Dick Butler's explanation for not advising
crow-hops............just out of curiosity. My experience has been the
crow hop was actually more intensive than a high tow, maybe that is
what he is getting at?

Brad

John C's comments are well said.

A few extra thoughts of my own.

"crow hops" (near heard that term before but I get it) might equate to a "high speed taxi" which is how the general aviation (GA) powered crowd might take a few hops off the runway to test the new hardware. This might work for self powered aircraft but not for a (non-powered) glider.

Think about a glider on a tow rope behind a tow plane. Having the tow plane pull you to take off speed, then you come back down and both you and the tow plane need to come to a halt in unison. The take off is the trickiest thing to master anyway, these hops you suggest would be REALLY tricky.

Of course there is this aspect of the first flight in a single place glider which very few powered GA pilots have ever experienced. Nearly all of them have flown with someone else in a 2 place before soloing it. Even a single place Pitts has a two place equivalent. The point is that gliders are different beasts with special needs. I don't mean to scare, just to get specialized training.

So, anyway, the common course of action is to take a high tow (5,000 ft AGL) early or late in the day, while pretending to execute landing patterns multiple times as you descend. That and a good briefing of the ship beforehand by the POH and an instructor you trust. Especially if this glider of yours is a CG hook and you have never flown one before.

Good luck and stay safe.

- John DeRosa

On Thursday, August 23, 2012 8:44:06 AM UTC-6, JohnDeRosa wrote:
John C's comments are well said.



A few extra thoughts of my own.



"crow hops" (near heard that term before but I get it) might equate to a "high speed taxi" which is how the general aviation (GA) powered crowd might take a few hops off the runway to test the new hardware. This might work for self powered aircraft but not for a (non-powered) glider.



Think about a glider on a tow rope behind a tow plane. Having the tow plane pull you to take off speed, then you come back down and both you and the tow plane need to come to a halt in unison. The take off is the trickiest thing to master anyway, these hops you suggest would be REALLY tricky.



Of course there is this aspect of the first flight in a single place glider which very few powered GA pilots have ever experienced. Nearly all of them have flown with someone else in a 2 place before soloing it. Even a single place Pitts has a two place equivalent. The point is that gliders are different beasts with special needs. I don't mean to scare, just to get specialized training.



So, anyway, the common course of action is to take a high tow (5,000 ft AGL) early or late in the day, while pretending to execute landing patterns multiple times as you descend. That and a good briefing of the ship beforehand by the POH and an instructor you trust. Especially if this glider of yours is a CG hook and you have never flown one before.



Good luck and stay safe.



- John DeRosa

Guys, I don't think you do "get it".

First, this is never done using a tow plane.
It is not "teaching yourself ground launch" since it's not a 'launch'.
It does not involve enough energy to endanger the pilot or glider.
Once upon a time, this is how everyone learned to fly a glider.
A tow car is used only if a bungee is unavailable.

The glider never gets more than a few inches above the runway nor more than 40 knots. It is done in steps starting with a ground roll just fast enough for aileron control and, if things go well, increasing to just barely liftoff speed. If the glider pilot starts to "lose it" the tow car releases the rope and stops well clear as the glider stops. It is never done in proximity to obstacles the glider could collide with.

It's best done in the early morning with a headwind which keeps the ground speed down.

I did this hundreds of times with an experimental flying wing sailplane as pilots learned its unconventional handling characteristics. No one had a problem, the glider was unscathed and all quickly gained the skills to fly the glider well. If the pilot was really inexperienced, I did a couple of dual "ground slides" and "crow hops" in a 2-seat trainer to get them used to the idea.

Northern European countries like Lithuania still do this with primary gliders. Even young children learn to fly them. Google "LAK 16" videos.

On 8/23/2012 11:07 AM, Bill D wrote:
On Thursday, August 23, 2012 8:44:06 AM UTC-6, JohnDeRosa wrote:
John C's comments are well said.

A few extra thoughts of my own.

"crow hops" (near heard that term before but I get it) might equate to a
"high speed taxi" which is how the general aviation (GA) powered crowd
might take a few hops off the runway to test the new hardware. This
might work for self powered aircraft but not for a (non-powered) glider.

Think about a glider on a tow rope behind a tow plane. Having the tow
plane pull you to take off speed, then you come back down and both you
and the tow plane need to come to a halt in unison. The take off is the
trickiest thing to master anyway, these hops you suggest would be REALLY
tricky.

Of course there is this aspect of the first flight in a single place
glider which very few powered GA pilots have ever experienced. Nearly
all of them have flown with someone else in a 2 place before soloing it.
Even a single place Pitts has a two place equivalent. The point is that
gliders are different beasts with special needs. I don't mean to scare,
just to get specialized training.

So, anyway, the common course of action is to take a high tow (5,000 ft
AGL) early or late in the day, while pretending to execute landing
patterns multiple times as you descend. That and a good briefing of the
ship beforehand by the POH and an instructor you trust. Especially if
this glider of yours is a CG hook and you have never flown one before.

Good luck and stay safe.

- John DeRosa

Guys, I don't think you do "get it".

First, this is never done using a tow plane. It is not "teaching yourself
ground launch" since it's not a 'launch'. It does not involve enough energy
to endanger the pilot or glider. Once upon a time, this is how everyone
learned to fly a glider. A tow car is used only if a bungee is
unavailable.

The glider never gets more than a few inches above the runway nor more than
40 knots. It is done in steps starting with a ground roll just fast enough
for aileron control and, if things go well, increasing to just barely
liftoff speed. If the glider pilot starts to "lose it" the tow car
releases the rope and stops well clear as the glider stops. It is never
done in proximity to obstacles the glider could collide with.

It's best done in the early morning with a headwind which keeps the ground
speed down.

I did this hundreds of times with an experimental flying wing sailplane as
pilots learned its unconventional handling characteristics. No one had a
problem, the glider was unscathed and all quickly gained the skills to fly
the glider well. If the pilot was really inexperienced, I did a couple of
dual "ground slides" and "crow hops" in a 2-seat trainer to get them used
to the idea.

Northern European countries like Lithuania still do this with primary
gliders. Even young children learn to fly them. Google "LAK 16" videos.


It CAN be fun to arrive late to the party. :-)

So now that you've received advice spanning the entire spectrum, how best to
sort it out?

My - utterly free, complete with money-back-guarantee - advice includes:

1) The devil is ALways in the details, and I haven't seen any advice I'd say
is flat out "wrong"...even though plenty of it is conflicting. There
definitely are some useful lessons therein... Proceed accordingly.

2) Yes, you'll be transitioning to a new-to-you single-seat sailplane, but
(based on what you originally wrote) not to a new-to-flight sailplane. I and
every previous responder have done that multiple times; it's one of the
personally intense joys of this grand sport. Point 'A' being, it's not THAT
big a step into the unknown, given many do it safely every year, all around
the globe. Certainly it's not in the same category as acting as a test pilot
to a new-type-sailplane. Point 'B' being there are some sound reasons
supporting the fact most pilots today transitioning to ships of the
performance of your Apis 13M do NOT use the "crow hop" approach. One is that
very few have direct experience with it anymore. (Blame this on the advent of
2-seat trainers post-WW-II. Bill D. - whose aviation [power &
glider]/instructor experience I seriously respect - is an exception, and, note
his referenced "crow hop" experience had both more direct availability of
people with similar experience [because it was decades ago], and, involved
test-flying a new, non-standard/flying wing design. Very prudent
decision/approach under those circumstances, IMHO. Why would you want to
involve yourself with others equally new to what *they're* doing [i.e. "crow
hopping"] as you will be to what *you're* proposing doing? Knee jerk answers
will be downgraded.) Meanwhile John C. touched upon a 2nd reason most
transitions as you've asked about are TODAY arguably most safely done by high
aero tow...i.e. rapidly getting as far away from big, hard things you can hit,
using a tow method with which you (and others) are thoroughly familiar with is
prudent indeed.

3) Brad (Hill - builder/pilot of an Apis 13 w. 800 hours on it & a prior
responder in this thread) apparently used John C.'s recommended approach to
his first flight in his Apis. He alluded to why. Most Definitely pick his
brains before you make your transition flight. Be sure to ask not only "what"
but "why?"

4) If you haven't already, be sure and have a discussion about "PIO" with your
instructor(s) regardless of which approach you pursue.

Have fun! (Just to be anal, I'll note that you won't have much fun if you
crunch something, so there's no need for me to advise, "Be safe!")

Bob W.

On Thursday, August 23, 2012 12:44:22 PM UTC-6, Bob Whelan wrote:
On 8/23/2012 11:07 AM, Bill D wrote:

On Thursday, August 23, 2012 8:44:06 AM UTC-6, JohnDeRosa wrote:

John C's comments are well said.



A few extra thoughts of my own.



"crow hops" (near heard that term before but I get it) might equate to a

"high speed taxi" which is how the general aviation (GA) powered crowd

might take a few hops off the runway to test the new hardware. This

might work for self powered aircraft but not for a (non-powered) glider.

On 8/23/2012 6:54 PM, Bill D wrote:


Major snip of intervening nuance...


Bob, you will recall your wife's first flight in her 1-26. I was certain
she was good to go after training her in a 2-33 but she wasn't so sure. To
her, the 1-26 looked scary - it was her first single seat transition.

Actually, I'd forgotten that detail, Bill, until this reminder!

So, I tied two or three aero tow ropes together and towed her with my Jeep.
The first ground roll was below liftoff speed she over-controlled the
ailerons as I had promised she would. The next try she was straight and
true so I nudged the speed up a bit until the 1-26 lifted off to about 3
feet where she released as instructed. I wheeled the Jeep away from the
runway and she glided straight ahead about 100 yards to a perfect landing.
Her grin just wouldn't go away. Now she KNEW she could fly her 1-26.

Ground skims are a very old technique but they can still serve a purpose.

"I agree!" with both those closing statements. What I was seeking to convey to
the O.P. in this particular regard (the devil being in the details) was it may
matter to him (and his transitional success) how experienced every one of his
helpers is in whatever job he asks them to competently perform. Me knowing
none of those details, my guess is in today's world he's more likely to find
folks competent in aerotowing than in "crow hopping" at his home field.

I suspect we're both in agreement that reducing variables when transitioning
to a new-to-the-pilot ship is arguably "more safe" than increasing them is
likely to be.

In any event, I hope he lets RAS know how the transition goes...and how he
accomplishes it!

Bob W.

Thanks for all the comments, and the few direct emails. Due to the time required I can't respond to all the issues raised.

Yes it is an Apis 13m, which was well built by Robert Mudd and then owned by Evergreen Soaring. I suspect Brad may have even flown it. I have read all the flying reports I can find about it, and I would respect anything Brad might add from his vast experience flying one.

My attitude still is that the crow-hop process I described is not a bad idea. And a few others here, with experience doing it, seem to agree. I have done many of them in new powered ultralights. For me it relieved the pressure of the transition, reducing the chance of “task over-load”, by getting more familiar with, and experience with some of the critical phases of flying before the actual flight, and thus reducing the risk.

I would also think that crow-hops in a towed glider are probably no big deal to do. The process is likely no different than practicing a rope break before the tow plane gets airborne, where you land straight ahead on the runway. So it is probably not a bad idea for others to practice it anyway.

A couple of useful things I did pick up on:

The comment which said watch out for PIOs rang a bell with me. I had that problem with one of the ultralights I designed and was crow-hop testing, when trying to test a new control while just a couple feet off the ground. That could be a problem in the Apis when reaching forward to release, or when unlocking the air brake. So I thought that unlocking the air brake first, like it would be anyway during a landing, and keeping the Apis on the ground with a forward stick while it gets up to speed, then release while still on the ground, then let it rise a few inches if there is enough speed left, then pull on the air brake, and then let it touch down and roll out like any normal landing.

The other concern might be allowing it to rise too high in a zoom climb, then stalling. But that is probably no different than any landing and not likely to happen to an experienced pilot.

Of course I'll discuss the crow-hop idea with my instructor, who is probably reading this RAS discussion anyway, and who has had a lot of experience in transitioning students to other gliders.

My Apis flying is still a few weeks away, so there is plenty of time to consider it, maybe even time for some others to try it and report back to RAS.

Thanks again,
Jerry Booker

My "worth what you paid for it" opinion:

You are overthinking the problem. This is a known design with no unusual characteristics. Take a high tow, get the feel of the controls, do some practice approaches, feel the changes when you open and close the spoilers, etc.. By that time you will know how it flies - then land it.

Crow hops are not usually done anymore for a reason - they are not necessary for normal aircraft. And I can think of several ways for things to go wrong with a relatively high performace glider (it's not a primary!) at low altitude when you are concentrating on doing a lot in a short time. Wrong place to be if something distracts you, etc... Think about it. Get away from the ground so you have the options of sorting things out.

Crow hops for testing a new design or for no-instructor primary training is a completely different thing.

Kirk
66

On Aug 24, 9:31*am, "kirk.stant" wrote:

Crow hops for testing a new design or for no-instructor primary training is a
completely different thing.

I'm with Kirk on this. For a new pilot in a proven aircraft, I would
recommend a high tow that gets as far from the ground as quickly as
practical so you can figure out how to fly it and use its systems.

I'm one of the folks who recommended that Brad use what you might call
"crow hops" on his latest completion, the Tetra-15. The situation
there was very different from the one at hand. Brad is an experienced
pilot in sailplanes and hang gliders, but the aircraft was an unproven
example of an unproven design. And I should know, I designed and
helped build most of its important bits.

I supervised the main wing rigging and conducted the static test to
Utility category load factor, and I was pretty sure it was all going
to work out fine, but there's still an anxious gap between pretty sure
and absolutely certain. The crow hops ensured that if we miscalculated
or just plain missed something, it would come to light at a potential
energy (altitude) state and kinetic energy (speed) state such that
both could be brought to zero without bringing to bear a lethal energy
gradient (deceleration).

For the first flights, my main concerns were that we would find that
either we had mis-rigged the wings and it would have turning tendency,
or that we had miscalculated either weight and balance or stability
and control and it would not have good stability or control in pitch.
The "crow hops" would have revealed any of these conditions with ample
margin to rein it in before anyone or anything gets hurt.

However, it all turned just as we had hoped and planned. It flies
straight, has good stability and good control response, performs well,
and I can't get Brad to stop flying it long enough to show it off on
the ground. Which is as it should be, I think.

Thanks, Bob K.
http://www.hpaircraft.com
https://www.facebook.com/pages/HP-24...t/200931354951