Rolladen- Schneider LS3A flap seals- Do they really make any difference?

[dennis raphael]

The flap seals at the wing root consantlty seem to get bent up , fall
off, and otherwise look lousy. How much good do they really do for a
recreational soaring pilot??? Any differnce in flight charactoristics
I will notice?. For those who dont know what I am talking about, the
seals are a piece of flexible plastic that attach to the top and
bottom of the flap next to the fusalage to seal a 3/8 in gap at the
rear 5 inches of the wing root where the flap raises and lowers.
thanks

[Greg Arnold]

Never noticed any difference on my '3, though Johnson did find they improved
climb.

"dennis raphael" <dennis...@hotmail.com> wrote in message
news:40d38c8d.01070...@posting.google.com...

[November Bravo]

The are two LS3's at oour club, and aoriginal flaperon LS3 and an LS3A.
Both have the seals and both showed a significant performance increase.
Have never had a problem with the seals coming off or getting bent.

"dennis raphael" <dennis...@hotmail.com> wrote in message
news:40d38c8d.01070...@posting.google.com...

[clay thomas]

"November Bravo" <jjb...@iserv.net> wrote in message news:<vf017.20159$AM.5...@e420r-sjo3.usenetserver.com>...

I made some new ones two years ago and have had no problem. I used
clear mylar obtained at a drafting supply house. I attached with high
quality double sided 3M tape. Let me know if you need the templates to
cut new ones.If the thichness of the mylar is correct,they will never
fold over in flight.

[p...@aigroupinc.com]

please send the templates. thanks pck at aigroupinc.com

[chip.b...@gmail.com]

I owned an original LS 3 for many years. Never had a problem with the seals in flight. But the wing root brackets in the factory Komet trailer would crease them unless they were taped together in a gentle curve before lowering the lid. I think I recall adjusting the brackets in the trailer to eliminate this problem. Dick Johnson's testing indicated there was some performance loss without the seals. I know of at least one owner who used auto body putty to build up a flat spot on each side of the fuselage so the butt end of the flaps could "wipe" against them (with a felt seal) and dispense with the flexible seals entirely. I watched them perform this minor modification in the hangar on a rain day at a contest back in...1979? :)

Chip Bearden
ASW 24 "JB"
U.S.A.

[KiloKilo]

You were flying contests in 1979? You must be one of those legacy soaring pilots ...:-) kk

[obi...@googlemail.com]

Hi,

it would be great if anybody could send me some information on how to build these seals (templates, dimension, material, etc).

Thanks,
--oliver

[Sierra Whiskey]

I Just recently made some using this Template:
http://www.goddard.com/wipers/wiper1.pdf

They seem to be working great. I ordered some 0.040" thick Mylar which seems to work perfect. I selected a thicker material to see if it would be more robust than what I had before. The material before was quite thin and tore in a couple places. I have about 50 hours of flying on my new wipers and they appear to be holding up quite well. I may go back and re-cut them this winter just to make them about 1/4" wider, but we will see.

-SW

[larry....@gmail.com]

On Friday, July 25, 2014 1:04:22 PM UTC-4, Sierra Whiskey wrote:
> I Just recently made some using this Template:
>
> http://www.goddard.com/wipers/wiper1.pdf
>

Here is the url for the templates along with revisions I made to the above design and pix of them installed.

Regards,

Zero One (Larry Goddard)

[larry....@gmail.com]

Oops...
Here's the URL === http://www.goddard.com/wipers/

[jfitch]

Not an LS but a PIK 20D I had. Same issue, flaps coming into the fuselage junction. The previous owner had sawed off about 5 inches of the flap and glassed it to the wing fixed. That made it easy to tape the wing/fuselage junction properly because nothing at the root moved. I will not pass judgement on the legality of such work, but I was the envy of all the other PIK owners.

[Bill Palmer]

RE "I ordered some 0.040" thick Mylar"

DO you mean 0.004" thick (extra zero in there)
Clear Polysester Film

McMaster part # 8567K42
https://www.mcmaster.com/#polyester-(pet)/=1bmm306


My LS3 seals are getting a bit ratty looking too.

Thanks wfpalmer at gmail

[Charlie M. (UH & 002 owner/pilot)]

I would really think it is supposed to be 0.040" thick, that's like a couple sheet of paper, your number is very thin.

[Dan Marotta]

Think of the spark gap in an automotive spark plug.  That's normally
around .028" to .032".  Some electronic ignitions call for a larger
gap.  Borrow a set of feeler gauges or a caliper and see what .040"
looks like.

On 2/18/2018 6:26 PM, Charlie M. (UH & 002 owner/pilot) wrote:
> I would really think it is supposed to be 0.040" thick, that's like a couple sheet of paper, your number is very thin.

--
Dan, 5J

[ronald...@gmail.com]

I have been using 14 mil (.014") mylar for many years for the flaperon/fuselage seal. I attach them with low profile velcro, and remove the seals before trailering so the clamshell/wing brackets don't damage them. I also make a narrow rub strip from velcro (fuzzy side) for the edge that rides on the fuselage. If you sand and clean the mylar before sticking the velcro it seems to bond well. Got the mylar on Amazon. You can order it by the foot. 24 inches wide.

I can't answer the question as to whether they help, but I would bet they don't hurt....

RC

[srath...@gmail.com]

I have owned an LS3-a for 9 years. It came without the mylar wipers and I added them after a couple of years flying without. One thing I noticed right away was that it is noticeably quieter at all speeds. I used two strips of the double sided mylar tape on the first try and I lost one while flying. I ended up reattaching them using contact cement after scuffing up the flap surface with a Scotchbrite pad. They have stayed on ever since. The mylar I used came from the leading edge of a hang glider I used to own. This mylar is considerably thicker than what I have seen on other ships. It is very durable and it bends and pushes against the fuselage making a good seal. I don't know for sure if it improves performance or not but it can't hurt and it will help your performance if you believe.

[Dan Marotta]

Oh...  Flap to fuselage wiper seal.  I thought you were talking about
the flap to wing seal.  I made those for my Mosquito decades ago from
material pulled from the trash cans in the hardware engineering lab
where I worked at the time.  I don't know the thickness of that stuff. 
It was used for engineering drawings.

--
Dan, 5J

[jj.nu...@gmail.com]

Dick Johnson experimented extensively with sealing the gap between the flaperon and fuselage on one of the very early '3s after he found the polar curve to be erratic in the 70-80kt region. Fitting some rough seals apparently removed a 'notch' in the curve at about 75kts and smoothed the polar straight away - with improved performance.

I flew my LS3 without them once and was surprised how noisy it was. Anything above 80kts and the wing-fuse junction got louder and louder until it was really screaming above 100kts. Swift changes in angle of attack presumably sent the airflow shooting up through the gap, where it mixed with the turbulent flow off the wing top surface and hit the tail causing the pilot to feel a buffet through the stick. Fitting mylar seals as people have mentioned fixed everything.

When they get old they sometimes don't seal as well and can buzz at high speed. What annoys me more though is the increased stick loads when driving the flaperon which has four mylar seals constantly rubbing against the fuse. I flew a different LS3 once which had a fairing built up on the fuesalage to make the gap maybe 2-3mm, and then felt to fill the gap. I think that is the best solution (best of both worlds) but its a lot of work.