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Pat Teakle AW20 repair
A couple years ago I bought a broken ASW20, it is
now repaired and flying.
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The Full Sized
The Schleicher AS-W 20 entered
production in 1976 winning numerous world and national championships.
Built for the 15-Meter Class, it features trailing edge flaps which
interconnect with the ailerons and allow the entire trailing edge to
operate as a flap between -9 and +50. The flaps also act as ailerons,
but deflect only half of the aileron amount. The fuselage is identical
to that of the AS-W19, but the elevator is shorter. Conventional speed
brakes are provided on the upper wing.
The model
A 1:3.5 Pat Teakle fitted with the extra wing tips
taking the span to 192 inches a very large model but not too heavy at
13lbs. A tow release is fitted, also a wheel but no retract |
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The repair
The fuselage was broken in half about a foot behind the wing root, I
made a fibre glass tube fitted this on the inside and glued it back
together. The joint was then ground away with an angle grinder down to the tube and glassed,
as Andy Westgate's tips on the club web site ( minus the paint job). I
did away with the elevator linkage from the front and fitted a mini
servo in the Fin
Radio Set up
The radio set up is much like the full size, Ailerons
are mixed to flaps 50% and flap to ailerons 75%. Landing flaps are on a
two position switch and elevator mixed in to give zero pitch change (not
scale like) Rudder mix and snap flap are also used the brakes are on
the throttle stick, Crow is not used but the ailerons do go up 5 degrees
on max landing flap to reduced the chance of a tip stall at slow speed. |
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First flight
The first flight was at Frocester Friday morning, 15MPH
west south west ideal for a first flight, After a very nervous function
check I could not think of another reason to delay the launch; the birds
looked happy in the strong lift apart from three crows having a fight A
little trot then I dropped it over the edge allowing the
model to fall and pick up air speed, it slowly pulled out of the dive
and came to level flight unaided. I had a long first flight being
careful of the height with the Bristol Gliding club launching every
minute for the Nationals. I tried to enjoy the flight and not let the
landing worry me, all the trims seemed spot on except for the 2nd
landing flap position which needed less down elevator. The wings had a
huge bend while looping and rolls were very slow compared to F3B type
models. I spent some time trying to induce a tip stall and failed the
model stalling straight and very late, just a bit of a nod.
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Landing,
This needs a lot of care at Frocester, first stay calm, down to the bend in river, turn into wind,
half flaps, a little brake to loose height, over the trees, full flap and up the
slope, but 10 feet too high, after several passes it flopped down with
the bracken supporting it 2 feet from the ground, now I could stop
holding my breath.
If you wish to land anything fragile at Frocester, adjust the
brake/elevator compensation to give zero pitch change, this unloads the
pilot allowing you to concentrate on hitting the spot; plenty of flap help slow the model, air brake or up ailerons
helps kill the lift. A slow stall into the bracken is my choice, there
are brambles down there which can tear fabric covered models. |
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Flying
This is not an easy model to fly, a careful balance is
needed with ailerons and rudder to get the turns right a slight lead
with the rudder so that
the ailerons are aided by the dihedral helps,
the turning circle is very large. The wings bend
so much I have to be gentle with the elevator while looping.
It would suit the scale
enthusiast as it looks very real in the air if flown at scale
speed. The 10 inch brakes don't seem to do much, but combined with
flaps slow it up well for landing
John Bennett's ASW20 also a Pat Teakle and built by John flies better than mine, more aerobatic
easily doing a rolling circle, loops are faster without the
excessive wing bend.
I am not a keen scale flier, but I do own a Pik20, Vega and ASW27, the
first two are Pat Teakle models
Phil
John's ASW20 Kit review, click
here asw20q
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Peter Wolf flying so I could take some
pictures, that's me in the RH picture launching at Frocester, doing a
Max Wall silly walk
click for larger images
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