Nice you got to fly with some of Rick's handiwork.
I did do a direct comparison with his last glider mod, an LS-4 he bought
after a fire consumed his 20 and many other gliders at a comp. We had flown
together in the LS-4s and they were about the same. After a lot of work with
root fairings made of modeling clay, tuft testing using an enormous VHS
camcorder, Rick made better fairings for his 4 and added a tail tank.
Next time we were climbing together performance seemed identical. But I was
flying dry and he was full of water. Left me behind in cruise.
Just a wing root fairing and a tail tank!
Good comparison. Both at MGW, the LS6 will climb with an ASW20 but leave the
20 behind. Seen it me against a good 20 pilot so it had to be the glider.
Jim
________________________________
From: Mike Borgelt <[email protected]>
To: Jim Staniforth <[email protected]>; Discussion of issues relating to
Soaring in Australia. <[email protected]>
Sent: Monday, May 6, 2013 4:49 PM
Subject: Re: [Aus-soaring] ASW20's
ASW20:
The A model and F model are essentially identical. The F was built
in France under licence.
Gross weight 454Kg.
Wortmann FX62 131 at root (actually the 15.3 % version tapering to 14.4%
at end of taper break), becoming FX60-126 at tip.
Some late A models got a gross weight increase if the fuselage was light
enough. As high as 508 Kg I think.
The B model has a gross weight of 525Kg and the lower wing surface was
changed to be thicker aft to encourage more laminar flow. To prevent
laminar bubbles blow hole turbulators were installed. Stainless steel or
mylar foils were used also to seal the control surface gap on the bottom.
Significantly higher empty weight due to extra structure and less bendy
wings as a consequence.
The C is the same but with the extra structure to cope with the higher
weight removed so the empty weight is lighter and weight was the same as
the A model. I don't know if any C models ever got approval for a higher
than 454Kg gross.
I'm not sure the wing lower surface mods did anything for performance.
That wing as built was a fair way from what Schleicher intended. Ron
Sanders got the drawings and fixed up his 20B and did the correct leading
edge. Seemed to be a little better.
On the 20B I flew in Texas in 1986 Rick Wagner had fitted a tail tank. I
was sceptical until I flew it half full one day and filled it up
thereafter. Also putting mylar seals on the top of the control surfaces
helped. Felt much more solid in thermals.
I talked with Rick a couple of times about his ASW20 mods. He used to
have a photo of tuft comparisons on his workshop wall.
The standard downturned tips are terrible. I don't think any current
designs have them. I removed them from my Mini Nimbus and substituted
ones more like the LS4 and what Rick did but before I learned about
his.
Better wing root fairings are a good idea, particularly extending the
fairing forward at the leading edge. Look at the nacelle/leading edge
fairings on a P-38. Or a Salto.
As ever, the biggest problem is finding out whether the mods really make
much difference.
Mike
At 08:58 AM 7/05/2013, you wrote:
Since all the ASW20BHs
have passed their time as an H, isn't the biggest performance difference
between stock ASW20s the MGW of the 20B? Doesn't mean much at reference
weight.
>Heard of people who have removed the pitots, put the turbulator tape over
the blow holes of the C.
>There's a "Frankenglider" or two with the great combination C
fuselage and A wings.
> For those unfamiliar, the ASW20BH was the limited time at a higher
red line "Hobbs Special", all low serial number B models raced
in the '83 Worlds.
> Of course, the best 20s are not as they came from the factory, but
ones modified by Rick Wagner. All the ASW20s he saw were EXP. Rick's
recipe:
>Cut off inner end of flaps, bond to the wings.
>Build better wing root fairings. Think ASW27 with the fairing extending
forward of the leading edge to the canopy rail.
>Cut off outer end of ailerons.
>Cut off wing tips. Discard.
>Build new wing tips. (looked between the LS-4 and original ASH26E curved
tip)
>If it doesn't have a tail tank, add one.
>Modify the trailer so the wing root fairing fits in the roof and clears
the floor, and adjust tip hold downs.
> Wil Scheuemann's recipe was more like:
>Remove skin of outer trapezoid.
>Replace with same airfoil as inner panel.
> That would probably spin like a top if you didn't behave, but go
like a bat out of hell.
>But unlike H301 Libelles, there are no Scheuemannised ASW20s, with or
without Sebastian Kawa.
>All those ideas were pre- wingletty things.
> Unfortunately the best example of Rick Wagner modified ASW20s was
destroyed a while ago. Believe Rick's wingtip moulds have been lost, and
none of the other modified 20s have all the mods. One has the aileron,
flap and tip mod but not the last version of the fairing.
>Jim
>
>
>From: Adam Woolley
<[email protected]>
>To: Discussion of issues relating to Soaring in Australia.
<[email protected]>
>Sent: Monday, May 6, 2013 2:52 PM
>Subject: [Aus-soaring] ASW20's
>
>If four ASW20's, one of each variant (a, b, c, f) were put in perfect in
flight test flying factory conditions - all with the same reference
weight of 400kg.
>
>Which one would out perform the other? Or, would they all perform
identically?
>
>Keen to hear reasoning if one knows the answer (I don't, hence the
Q).
>
>
>Cheers,
>WPP
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>
>
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instrumentation since 1978
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