PDA

View Full Version : Frise ailerons on sailplanes


Mark James Boyd
February 24th 05, 08:11 AM
I was thinking recently about ground loops and flaperons and
adverse yaw and crosswinds. I can understand how
one needs a rudder for sideslips, but beyond that:

Is anyone making a modern competition glider without adverse yaw
using frise ailerons?
How about one that had no ailerons but just spoilers for roll?

Frise ailerons are made so that when one aileron goes down and
increases drag, the other aileron going "up" has a drag
edge on the bottom which increases drag on the opposite side
equally. So when the ailerons are deflected, there is
no adverse yaw, only increased drag on both wings equally.

Neat on the Duchess and the Aero Commander (twin engine planes)
but haven't heard of it in competition gliders.
Also haven't heard of rudder-aileron interconnect for gliders.

I have heard that some big jets, perhaps 737 and such, use spoilers
for additional roll authority as well.
And the U-2 was rumored to have twisting trailing edge landing gear,
so landing in a crosswind in a crab was fine.

The aircoupe combined a lot of these features to make a plane without
a rudder.

Have gliders other than the MDM-1 Fox or SZD 22C Mucha
tried frise ailerons?
A friend is building a Carbon Dragon,
which uses flaperons. Although that sounds great (nice speed
range) I wonder about the adverse yaw.

Ok, ok, maybe a frise type settup isn't aerodynamically efficient
(since there is extra drag during each roll in/out) but then again
lots of rudder during a roll isn't that efficient either.
Did some sailplane designer do a bunch of math and conclude
that frise ailerons, or using spoilers only, just wasn't
gonna work for sailplanes? Or has it just not been done generally...

The Mucha 22C took 1st place in the 1958 Standard Class world championships.
(according to the sailplanedirectory).
Was this the last time frise ailerons made a "splash" in gliding?
--

------------+
Mark J. Boyd

Bert Willing
February 24th 05, 10:02 AM
No one wants increased drag on the wing if you can avoid it with the rudder.

--
Bert Willing

ASW20 "TW"


"Mark James Boyd" > a écrit dans le message de news:
421d8c46$1@darkstar...
>I was thinking recently about ground loops and flaperons and
> adverse yaw and crosswinds. I can understand how
> one needs a rudder for sideslips, but beyond that:
>
> Is anyone making a modern competition glider without adverse yaw
> using frise ailerons?
> How about one that had no ailerons but just spoilers for roll?
>
> Frise ailerons are made so that when one aileron goes down and
> increases drag, the other aileron going "up" has a drag
> edge on the bottom which increases drag on the opposite side
> equally. So when the ailerons are deflected, there is
> no adverse yaw, only increased drag on both wings equally.
>
> Neat on the Duchess and the Aero Commander (twin engine planes)
> but haven't heard of it in competition gliders.
> Also haven't heard of rudder-aileron interconnect for gliders.
>
> I have heard that some big jets, perhaps 737 and such, use spoilers
> for additional roll authority as well.
> And the U-2 was rumored to have twisting trailing edge landing gear,
> so landing in a crosswind in a crab was fine.
>
> The aircoupe combined a lot of these features to make a plane without
> a rudder.
>
> Have gliders other than the MDM-1 Fox or SZD 22C Mucha
> tried frise ailerons?
> A friend is building a Carbon Dragon,
> which uses flaperons. Although that sounds great (nice speed
> range) I wonder about the adverse yaw.
>
> Ok, ok, maybe a frise type settup isn't aerodynamically efficient
> (since there is extra drag during each roll in/out) but then again
> lots of rudder during a roll isn't that efficient either.
> Did some sailplane designer do a bunch of math and conclude
> that frise ailerons, or using spoilers only, just wasn't
> gonna work for sailplanes? Or has it just not been done generally...
>
> The Mucha 22C took 1st place in the 1958 Standard Class world
> championships.
> (according to the sailplanedirectory).
> Was this the last time frise ailerons made a "splash" in gliding?
> --
>
> ------------+
> Mark J. Boyd

Stefan
February 24th 05, 10:59 AM
Mark James Boyd wrote:

> I was thinking recently about ground loops and flaperons and
> adverse yaw and crosswinds. I can understand how
> one needs a rudder for sideslips, but beyond that:

Looking at your posts (this one and those concerning crosswind landings,
I come to the conclusion that you have a problem with correct rudder use.

> Is anyone making a modern competition glider without adverse yaw
> using frise ailerons?

I don't know the origin of the legend that rudder is only needed to
compensate for adverse yaw. But as a proper turn is a movement around
all three axis, you always need all three controls for a proper turn,
with or without adverse yaw.

Stefan

February 24th 05, 11:09 AM
Since sailplanes overbank in steep turns applying the required opposite
aileron would then create even more adverse yaw.

One reason that the Carbon Dragon has full-span flaperons is that they
are driven from the root end only, avoiding the need to clutter the
wing structure with pushrods, cables, pulleys, etc.

Jonathan Pitt

February 24th 05, 11:09 AM
Since sailplanes overbank in steep turns applying the required opposite
aileron would then create even more adverse yaw.

One reason that the Carbon Dragon has full-span flaperons is that they
are driven from the root end only, avoiding the need to clutter the
wing structure with pushrods, cables, pulleys, etc.

Jonathan Pitt

Stefan
February 24th 05, 11:10 AM
Mark James Boyd wrote:

> I was thinking recently about ground loops and flaperons and
> adverse yaw and crosswinds. I can understand how
> one needs a rudder for sideslips, but beyond that:


Looking at your posts (this one and those concerning crosswind
landings), I come to the conclusion that you have a problem with correct
rudder use.

> Is anyone making a modern competition glider without adverse yaw using
> frise ailerons?

I don't know the origin of the legend that rudder is only needed to
compensate for adverse yaw. As a proper turn is a movement around all
three axis, you always need all three controls, with or without adverse yaw.

Stefan

John Giddy
February 24th 05, 12:27 PM
On 24 Feb 2005 00:11:50 -0800, Mark James Boyd wrote:

> I was thinking recently about ground loops and flaperons and
> adverse yaw and crosswinds. I can understand how
> one needs a rudder for sideslips, but beyond that:
>
> Is anyone making a modern competition glider without adverse yaw
> using frise ailerons?
> How about one that had no ailerons but just spoilers for roll?
>
> Frise ailerons are made so that when one aileron goes down and
> increases drag, the other aileron going "up" has a drag
> edge on the bottom which increases drag on the opposite side
> equally. So when the ailerons are deflected, there is
> no adverse yaw, only increased drag on both wings equally.
>
> Neat on the Duchess and the Aero Commander (twin engine planes)
> but haven't heard of it in competition gliders.
> Also haven't heard of rudder-aileron interconnect for gliders.
>
> I have heard that some big jets, perhaps 737 and such, use spoilers
> for additional roll authority as well.
> And the U-2 was rumored to have twisting trailing edge landing gear,
> so landing in a crosswind in a crab was fine.
>
> The aircoupe combined a lot of these features to make a plane without
> a rudder.
>
> Have gliders other than the MDM-1 Fox or SZD 22C Mucha
> tried frise ailerons?
> A friend is building a Carbon Dragon,
> which uses flaperons. Although that sounds great (nice speed
> range) I wonder about the adverse yaw.
>
> Ok, ok, maybe a frise type settup isn't aerodynamically efficient
> (since there is extra drag during each roll in/out) but then again
> lots of rudder during a roll isn't that efficient either.
> Did some sailplane designer do a bunch of math and conclude
> that frise ailerons, or using spoilers only, just wasn't
> gonna work for sailplanes? Or has it just not been done generally...
>
> The Mucha 22C took 1st place in the 1958 Standard Class world championships.
> (according to the sailplanedirectory).
> Was this the last time frise ailerons made a "splash" in gliding?

You answered your own question: Too much drag in a high performance
sailplane which spends quite a lot of its time banked in a turn in
thermals.
What's wrong with using the rudder ?
Cheers, John G.

Udo Rumpf
February 24th 05, 02:37 PM
" > wrote in message
ups.com...
> Since sailplanes overbank in steep turns applying the required opposite
> aileron would then create even more adverse yaw.
>
> One reason that the Carbon Dragon has full-span flaperons is that they
> are driven from the root end only, avoiding the need to clutter the
> wing structure with pushrods, cables, pulleys, etc.
>
> Jonathan Pitt



Full span aileron will reduce the deflection to nearly half for any given
roll rate, which reduces deflection drag. With a one stage differential
input the control performance becomes even more advantages.
Naturally it also has disadvantages. An example of that arrangement is the
DG 800 series of gliders. It has less to do with clutter.
The best compromise in my opinion is the ASW 20 and 27 arrangement.
Regards
Udo

Jim Culp
February 24th 05, 02:42 PM
On the subject of spoilerons,
it is a fact spoilerons have been used on a US ATC'd
glider.

It is called the J4 Javelin.
It was in series factory production in the 1970s, and
8 were made.

Competitively, it came up against the popular influx
of German fiberglas gliders that offered in the US
market very high performance gliders such as the Glasflugel
Libelles, Schleicher Asw-15 etc.

The design and engineering was done by Max Peterson,
and production was by his company Peterson Sailplane
Corporation in California. This was reported on by
Dick Johnson.

Also, in June 1973 issue of Soaring magazine there
is the article by Max Peterson, and it is cited in
the SSA Sailplane Directory of 1983.

It was a single seat fixed landing gear all metal glider
aimed at the market for recreational, club, and commercial
operation glider use.

Interestingly, I think I recall the design used the
same parts for right, left and vertical tailfin control
surfaces although I am not sure of that.

A friend of mine, the late Tom Hulings of Mid Georgia
Soaring Association (he was WWII B-17 hero, who put
one of his shotup and then gliding B17s between hedgerows
backed by rocks in England; Tom also holds the WWII
record of bringing back the most shot up bomber of
WWII to base. He was in the Eighth
Air Force).

Tom Hulings did a number of flights in the Javelin
J4. He said he wanted to consider buying one. He

told me of his flying a J4 Javelin at Bermuda High
Soaring School (as a demonstrator?).

Tom Hulings reported to me that his flying the J4 was
interesting and that he enjoyed the experience but
that he did not care to buy one: that he could fly
it without problem; but that he did not care for the
spoileron roll response feeling in that it was not
as sensitive and not as quickly roll responsive as
he liked a glider to feel yet it was completely controllable.


Dick Johnson evaluated the J4 Javelin and wrote his
evaluation. put this into your browser and read-

http://web.ukonline.co.uk/sssrcsoaring/
Spotlight_Data/Javelin/J-4_JavelinArticle.pdf

Kindest regards,

Dancing on clouds,

Keep it up!

Jim Culp USA
Asw-20C
GatorCity Florida

Andrew Warbrick
February 24th 05, 02:45 PM
At 08:30 24 February 2005, Mark James Boyd wrote:
>Neat on the Duchess and the Aero Commander (twin engine
>planes)
>but haven't heard of it in competition gliders.
>Also haven't heard of rudder-aileron interconnect for
>gliders.
>

The Nimbus 4 has a mechanism whereby full rudder operates
a small portion of aileron at the tip so as to counteract
the adverse yaw at the expense of a reduced roll rate.

>I have heard that some big jets, perhaps 737 and such,
>use spoilers
>for additional roll authority as well.
>And the U-2 was rumored to have twisting trailing edge
>landing gear,
>so landing in a crosswind in a crab was fine.

Don't know about the U2 but I believe the B52 incorporates
both of these features, it has no ailerons at all,
entirely relying on differential spoilers for roll
control. Allows a lighter wing with less torsional
stiffness at the expense of awful handling 'feel' and
all of the wheels steer to allow crabbing on the ground,
both for taxying through small (small is a relative
term when you've got a 56m wingspan) gaps and landing
in cross winds.

Jim Culp
February 24th 05, 02:50 PM
On the subject of spoilerons,
it is a fact spoilerons have been used on a US ATC'd
glider.

It is called the J4 Javelin.
It was in series factory production in the 1970s, and
8 were made.

Competively, it came up against the influx of German
fiberglas gliders that offered in the US market very
high performance gliders.

The design and engineering was done by Max Peterson,
and production was by his company Peterson Sailplane
Corporation in California. That was reported on by
Dick Johnson.
Also, in your June 1973 issue of Soaring magazine there
is the article by Max Peterson, and it is cited in
the SSA Sailplane Directory of 1983.

It was a single seat fixed landing gear all metal glider
aimed at the market for recreational, club, and commercial
operation glider use.

Interestingly, I think I recall the design used the
same parts for right, left and vertical tailfin control
surfaces although I am not sure of that.

A friend of mine, the late Tom Hulings of Mid Georgia
Soaring Association (he was WWII B-17 hero, who put
one of his shotup and then gliding B17s between hedgerows
in England and who also held the WWII record of bringing
back the most shot up bomber of WWII to base). Tom
told me of his flying a J4 Javelin at Bermuda High
Soaring School (as a demonstrator?).

Tom Hulings reported to me that his flying the J4 was
interesting and that he enjoyed the experience but
that he did not care to buy one: that he could fly
it without problem; but that he did not care for the
spoileron roll response feeling in that it was not
quite as sensitive and not as quickly roll responsive
as he liked a glider to feel.

Dick Johnson evaluated the J4 Javelin and wrote his
evaluation. put this into your browser and read.

http://web.ukonline.co.uk/sssrcsoaring/
Spotlight_Data/Javelin/J-4_JavelinArticle.pdf

Kindest regards,

Dancing on clouds,

Keep it up!

Jim Culp USA
Asw-20C
GatorCity Florida

Jim Culp
February 24th 05, 03:26 PM
On the subject of spoilerons,

it is a fact spoilerons have been used on a US ATC'd
glider.

It is called the J4 Javelin.
It was in series factory production in the 1970s, and
8 were made.

Competitively, it came up against the influx of German
fiberglas gliders offered in the US market with very
high performance gliders such as Glasflugel Libelles
and Schleicher Asw-15s.

The design and engineering was done by Max Peterson,
and production was by his company Peterson Sailplane
Corporation in California. That was reported on by
Dick Johnson.

Also, in June 1973 issue of Soaring magazine there
is the article by Max Peterson, and it is cited in
the SSA Sailplane Directory of 1983.

It was a single seat fixed landing gear all metal glider
aimed at the market for recreational, club, and commercial
operation glider use.

Interestingly, I think I recall the design used the
same parts for right, left and vertical tailfin all
moving control
surfaces although I am not sure of that.

A friend of mine, the late Tom Hulings of Mid Georgia
Soaring Association (he was WWII B-17 hero, who got
off- airfield landing experience putting
his shotup and then gliding B17 between stonebacked
hedgerows in England;

Tom Hulings eternally holds the WWII record of bringing
back the most shot up bomber of WWII to base with over
2000 holes shot thru his plane. He was on the ball
bearing plant bombing mission August 17 1943 to Schweinfurt
w/ 8th Air Force).

Tom Hulings, a quiet, kind, and cheerful flight loving
gentleman, told me of his flying a J4 Javelin at Bermuda
High
Soaring School (there as a demonstrator). I am witness
to his statements on this glider.

Tom Hulings reported to me at length on our drives
together in his convertible 1970s Chevy between Altanta
and Monroe Ga,
that:
his flying the J4 Javelin was
interesting and that he enjoyed the experience
but
that he did not care to buy one:
that he could fly
it without problem;
but that he did not care for the
spoileron roll response feeling in that it was not
quite as sensitive and not as quickly roll responsive
as he liked a glider to feel.

Dick Johnson evaluated the J4 Javelin and wrote his
evaluation.

type this full webaddr below into your browser, click
and read. sorry it wont connect from clicking here
below.

http://web.ukonline.co.uk/sssrcsoaring/
Spotlight_Data/Javelin/J-4_JavelinArticle.pdf

Kindest regards,

Dancing on clouds,

Keep it up!

Jim Culp USA
Asw-20C
GatorCity Florida

Bert Willing
February 24th 05, 03:27 PM
Nimbus 3/4 have these spoilers because otherwise the rudder would need to be
substantially larger to provide sufficient yaw authority. Larger rudder =
more drag all the time, little spoiler = a little more drag only during the
beginning of a turn.

--
Bert Willing

ASW20 "TW"


"Andrew Warbrick" > a écrit dans le
message de news: ...
> At 08:30 24 February 2005, Mark James Boyd wrote:
>>Neat on the Duchess and the Aero Commander (twin engine
>>planes)
>>but haven't heard of it in competition gliders.
>>Also haven't heard of rudder-aileron interconnect for
>>gliders.
>>
>
> The Nimbus 4 has a mechanism whereby full rudder operates
> a small portion of aileron at the tip so as to counteract
> the adverse yaw at the expense of a reduced roll rate.
>
>>I have heard that some big jets, perhaps 737 and such,
>>use spoilers
>>for additional roll authority as well.
>>And the U-2 was rumored to have twisting trailing edge
>>landing gear,
>>so landing in a crosswind in a crab was fine.
>
> Don't know about the U2 but I believe the B52 incorporates
> both of these features, it has no ailerons at all,
> entirely relying on differential spoilers for roll
> control. Allows a lighter wing with less torsional
> stiffness at the expense of awful handling 'feel' and
> all of the wheels steer to allow crabbing on the ground,
> both for taxying through small (small is a relative
> term when you've got a 56m wingspan) gaps and landing
> in cross winds.
>
>
>
>

Gary Boggs
February 24th 05, 03:50 PM
If you want to see what can happen when you have no ailerons as all go to
this web site and scroll down to the B-52 crash.

http://www.alexisparkinn.com/aviation_videos.htm


"Andrew Warbrick" > wrote in message
...
> At 08:30 24 February 2005, Mark James Boyd wrote:
>>Neat on the Duchess and the Aero Commander (twin engine
>>planes)
>>but haven't heard of it in competition gliders.
>>Also haven't heard of rudder-aileron interconnect for
>>gliders.
>>
>
> The Nimbus 4 has a mechanism whereby full rudder operates
> a small portion of aileron at the tip so as to counteract
> the adverse yaw at the expense of a reduced roll rate.
>
>>I have heard that some big jets, perhaps 737 and such,
>>use spoilers
>>for additional roll authority as well.
>>And the U-2 was rumored to have twisting trailing edge
>>landing gear,
>>so landing in a crosswind in a crab was fine.
>
> Don't know about the U2 but I believe the B52 incorporates
> both of these features, it has no ailerons at all,
> entirely relying on differential spoilers for roll
> control. Allows a lighter wing with less torsional
> stiffness at the expense of awful handling 'feel' and
> all of the wheels steer to allow crabbing on the ground,
> both for taxying through small (small is a relative
> term when you've got a 56m wingspan) gaps and landing
> in cross winds.
>
>
>
>

Andreas Maurer
February 24th 05, 03:59 PM
On Thu, 24 Feb 2005 07:50:23 -0800, "Gary Boggs"
> wrote:

>If you want to see what can happen when you have no ailerons as all go to
>this web site and scroll down to the B-52 crash.
>
>http://www.alexisparkinn.com/aviation_videos.htm

In fact this is going to happen with any aircraft that you stall in a
steep turn close to the ground.


Bye
Andreas

jphoenix
February 24th 05, 04:26 PM
Some people that own Nimbus 3's do not connect the tip spoilers because
they say the effect is negligible. I connect them on mine, but I can't
really say how effective they are - they only come up in the second
half of stick input. I believe the Nimbus 4 arrangement with the tip
spoilers connected to the rudder makes much more sense as I almost
always use much more rudder than aileron when turning into a thermal.

More effective than the tip spoilers is to minimize adverse yaw in the
Nimbeast 3 with easy, patient roll rate - in other words, the faster
and farther I move the ailerons, the quicker I run out rudder - at
thermal speeds.

Once settled into the thermal, it's easy to keep on an even keel, but
it does like to overbank if you let it.

Occasionally, on bad thermal days I can move the ailerons and rudder as
much as I want and the beast just does not want to go where I want it
to!! Swearing seems to help. Other days, it's easy as pie. Probably
more to do with the control system located between the headsets than
anything else.

In any case, a little adverse yaw, overbanking and leg exercises
(rudder dancing) are a small price to pay for the horsepower available
in this glider. Someday I'll learn how to use it's potential - and I
have a lot to learn.

Jim




Bert Willing wrote:
> Nimbus 3/4 have these spoilers because otherwise the rudder would
need to be
> substantially larger to provide sufficient yaw authority. Larger
rudder =
> more drag all the time, little spoiler = a little more drag only
during the
> beginning of a turn.
>
> --
> Bert Willing
>
> ASW20 "TW"
>

Bill Daniels
February 24th 05, 06:21 PM
The use of spoilers as roll control on a sailplane has two major drawbacks
compared to ailerons with adverse yaw. These comments are based on flight
test of a roll spoiler equipped flying wing glider.

First, the relationship of drag to reduction in lift produced by the roll
spoiler changes dramatically with airspeed. There is only one airspeed
where the drag and roll produce a perfectly coordinated turn entry.
(Remember that drag increases with the square of airspeed.)

At airspeeds above the coordinated airspeed, the spoiler will produce too
much drag and the turn entry will skid unless outside rudder is used. This
is called proverse yaw.

At airspeeds below the coordinated airspeed, the roll spoiler will not
produce enough drag and the turn entry will be a slip unless into-the-turn
rudder is applied. (Adverse yaw)

The second major problem with roll spoilers is during a steady turn where
one would normally use top aileron to oppose overbanking. If the pilot
attempts to oppose overbanking with roll spoilers, the drag of the spoiler
will cause the glider to yaw away from the turn. The pilot will then use
into-the-turn rudder to center the yaw string which will cause the
overbanking to resume unless still more top spoiler is used. This will
quickly progress to the point where full top spoiler and full into-the-turn
rudder is applied. This is hardly conducive to a low sink rate.

The lession here is that adverse yaw is actually needed for steady state
turns. In a turn the airspeed and angle of attack varies across the full
span. This results in the outside wing having more drag and lift than the
inside wing causing overbanking. Top aileron restores spanwise symmetry of
lift and drag neatly taming the overbanking.

Adverse yaw is also useful for crosswind landings. Into the wind aileron
produces a down wind yaw that helps align the fuselage with the direction of
flight.

Another way to look at it is that differential spoilers produce a control
response that is not unlike the rudder. If the glider is equipped with both
rudder and roll spoilers it has, in effect, two rudder systems and therefore
lacks true 3-axis controls.

That said, differential spoilers actuated through the rudder control curcuit
can significantly augment a weak rudder.

Bill Daniels

February 24th 05, 06:45 PM
I flew a Javelin J-4 way back in the mid 70's at the old Vacaville
gliderport. Odd little glider, nice big cockpit, lousy drag spoilers,
horrible control feel throught the roll spoilers. OK performance as
long as maneuvering wasn't called for.

It crashed the day after I flew it - stall spin on base to final. I'm
convinced the accident was partially due to the poor glidepath control
and poor roll control - pilot probably got high on final, tried a 360,
then got low and lost it.

Interesting concept for a mid performance low cost glider, and with
conventional ailerons and better spoilers it might have worked - would
have been a nice club-class metal ship for clubs and FBO's.

Kirk

February 24th 05, 06:50 PM
1. Since most current high performance gliders carry their laminar flow
across the aileron gap, the drag penalty of a deflected frise aileron,
compared to the deflected rudder, would be huge.

2. Peterson J-4 Javelin - see later posts for more details.

3. Fox has NICE ailerons, for acro - I always had an irristible urge
to do slow rolls on tow when flying a Fox. Also real nice aileron
snatch at the accelerated stall break. It doesn't fly like a racing
glider, it flies like a little fighter plane.

Kirk

Markus Feyerabend
February 24th 05, 08:37 PM
>3. Fox has NICE ailerons, for acro - I always had an irristible urge
>to do slow rolls on tow when flying a Fox.....

Why didnīt you just do it, itīs fun! ;-)

Markus

PS: The Swift S-1 too has Friese-Ailerons (it has almost the same wing as
the Fox).

February 24th 05, 08:51 PM
Hmm, I just read my previous post and realized I typed "Fox" (the
two-seater) when I meant "Swift" (the single-seat S-1). Oldsheimers, I
guess - too early to be Gin and Tonic induced...

But to answer the question, I'm sure it would be fun, but I wasn't
flying the Swift often enough to feel really comfortable doing it - and
in Arizona I didn't have to take high tows (easy to thermal up to acro
height) so didn't get far enough away from the glider's owner to feel
good about it either!

At risk of topic-creep, how does the Fox compare to the Swift (flying
wise; I know what it looks like)?

Kirk

Bob Korves
February 25th 05, 01:37 AM
"Mark James Boyd" > wrote in message
news:421d8c46$1@darkstar...
(snip)
> And the U-2 was rumored to have twisting trailing edge landing gear,
> so landing in a crosswind in a crab was fine.
(snip)
> Mark J. Boyd

I have a friend that flew B-52's, C-5A's, and I believe 747's, all with
steerable landing gear. He said that it is a great idea in theory but that
with conventional gear you at least know that if the fuselage is lined up
with the runway then so is the gear. With steerable landing gear you have
to guess at the correction angle setting and then guess again at whether the
gear is aligned with the ground track at touchdown. He said that he
preferred to land with the gear straight whenever it was at all possible.
-Bob Korves

Markus Feyerabend
February 25th 05, 07:26 PM
>But to answer the question, I'm sure it would be fun, but I wasn't
>flying the Swift often enough to feel really comfortable doing it -

That makes sense!

>and in Arizona I didn't have to take high tows (easy to thermal up to acro
>height) so didn't get far enough away from the glider's owner to feel
>good about it either!

I see ;-)


>At risk of topic-creep, how does the Fox compare to the Swift (flying
>wise; I know what it looks like)?

Hereīs what I think (others might see it different):
The Fox has some advantages in the upward lines (due to more inertia). It
rolls a little slower (more span), but not much and the stick forces on
aileron are a tad heavier. I had less problems with rolling circles in the
Fox in the beginning, donīt know how it would be now. My success rate in
stall turns/hammerheads is 100% in the Fox, whereas in the Swift I still
fu.. up ever now and then! My Swift is said to be quite straight, but some
apparently are quite tricky in negative push-upīs. The Fox however is much
easier to push up negative (talk about tailslides with negative entry, my
personal nightmare in the Swift). The Fox flicks like mad, but I had more
problems doing a nice one (stop exactly). Later Foxes are much tamer than
early model Foxes. The early model Fox I flew was good for some amazing
flicks/acclerated stalls, late models are still good, but not that
aggressive. Seating is more comfortable in the Swift but I had no problems
in the Fox either (Iīm 5ft30). The fun-factor in the Fox is unbeatable with
the possibility to take somebody up, but for doing competition style
aerobatics, Iīm quite happy with my Swift and would not change.

Thatīs my personal experience after about 50 take-offs in the Fox vs. about
350 in my Swift.

Markus

February 25th 05, 09:15 PM
Thanks for a great description; I'm going to have to get back into a
Swift sometime soon and try that negative push up/tailslide!

My LS6 obviously isn't anywhere close for serious acro, but it does do
nice easy loops and biiiig slooow barrel rolls on occasion.

Come on spring, I need to look up at the ground again!

Kirk

Markus Feyerabend
February 25th 05, 09:43 PM
>Come on spring, I need to look up at the ground again!

You are soooo right! But the forecast looks more like "even more snow and
temperatures down to -10°F....."

Markus

Google