Fin Mounted TE Prob vs fuselage mounted TE prob

I have not received my soaring magazine yet this month but I hear there
is an article dealing with fin mounted vs fuselage mounted TE probes.

Anyone have thoughts on this issue?

Richard
www.craggyaero.com

wrote in message
oups.com...
I have not received my soaring magazine yet this month but I hear there
is an article dealing with fin mounted vs fuselage mounted TE probes.

Anyone have thoughts on this issue?

Richard
www.craggyaero.com


I read Dick's article with interest. He did his usual incredibly through
experimental work to support the probe design.

I see several advantages to the Johnson probe.

1. It's likely to be less sensitive to yaw with its single hole aft.
2. Shorter tubing runs that can be easily inspected and replaced if needed.
3. It eliminates the danger of breaking the fin mounted probe while
installing/removing the tail dolly.
4. Possibly faster and more accurate vario response since acceleration and
line capacity errors are reduced.
5, One less part to install (or forget)

Bill Daniels

One additional practical advantage to the fuselage
mounted TE:

If you forget to remove the TE probe from the fin-mounted
position and close the Cobra/Komet top with the glider
inside the trailer, you'll end up with another bend
in the TE probe.

That won't happen with a fuselage-mounted TE probe.

(Since I have a funky tube trailer, that isn't possible
with my ship. So, it didn't happen to me.)

Ray Lovinggood
Carrboro, North Carolina, USA

At 13:30 02 June 2005, Bill Daniels wrote:

wrote in message
roups.com...
I have not received my soaring magazine yet this month
but I hear there
is an article dealing with fin mounted vs fuselage
mounted TE probes.

Anyone have thoughts on this issue?

Richard
www.craggyaero.com


I read Dick's article with interest. He did his usual
incredibly through
experimental work to support the probe design.

I see several advantages to the Johnson probe.

1. It's likely to be less sensitive to yaw with its
single hole aft.
2. Shorter tubing runs that can be easily inspected
and replaced if needed.
3. It eliminates the danger of breaking the fin mounted
probe while
installing/removing the tail dolly.
4. Possibly faster and more accurate vario response
since acceleration and
line capacity errors are reduced.
5, One less part to install (or forget)

Bill Daniels

This placement was suggested for the PW5 I used to be a partner in.
Installation was simple and it worked as well as the fin implementation on
my Mosquito.
wrote in message
oups.com...
I have not received my soaring magazine yet this month but I hear there
is an article dealing with fin mounted vs fuselage mounted TE probes.

Anyone have thoughts on this issue?

Richard
www.craggyaero.com

On my LS-6 I have a small TE Leak somewhere between the bottom of the
Vertical Stabilizer and the TE Probe that's located on the upper
leading edge of the Vertical Stabilizer. The leak is most likely where
the tubing connects to the TE Probe. I think that I would need to cut a
hole in the Vertical Stabilizer to fix it! UGGHH!!!

This Fuselage mounted TE Probe would be a perfect fix for my situation.
My questions a How do you know where to place the probe on a
particular aircraft? How come nobody figured this sysytem out sooner.
Are there any down sides to this system??

On my LS-6 I have a small TE Leak somewhere between the bottom of the
Vertical Stabilizer and the TE Probe that's located on the upper
leading edge of the Vertical Stabilizer. The leak is most likely where
the tubing connects to the TE Probe. I think that I would need to cut a
hole in the Vertical Stabilizer to fix it! UGGHH!!!

This Fuselage mounted TE Probe would be a perfect fix for my situation.
My questions a How do you know where to place the probe on a
particular aircraft? How come nobody figured this sysytem out sooner.
Are there any down sides to this system??

Thanks for Any replies!

Jerz

For Example John Smith wrote:
This placement was suggested for the PW5 I used to be a partner in.
Installation was simple and it worked as well as the fin implementation on
my Mosquito.
wrote in message
oups.com...

I have not received my soaring magazine yet this month but I hear there
is an article dealing with fin mounted vs fuselage mounted TE probes.

Anyone have thoughts on this issue?

Richard
www.craggyaero.com

Hey, and how about those way cool wing root fairings! I don't believe
they are standard fare on S-H Venti A or B. Their lack is the biggest
lapse in the design IMHO.

Does anyone remember an article on this mod?

And congratulations to Dick for a timeless contribution to the science
and art of TE and all the other great work he has done for us. Gratis.

Bob Johnson

The Ventus A and B models really need a good wing root fairing.
Schempp-Hirth realized their mistake years ago, and offered a simple
aftermarket fiberglass fairing mod kit. I installed mine during the
early 80s, and it really helped the low speed performance.
I think it may still be possible to obtain a similar fairing, and
possibly Al McDonald or someone else knows where?
Dick Johnson

I won't receive my copy of "Soaring" until some weeks from now, so I
don't know exactly what's in it, and can merely make an educated guess
based on the comments in this thread, but:

1) It eliminates the danger of breaking the fin mounted probe while
installing/removing the tail dolly. On the original ASW-19 and -20, there is a fuselage mounted TE probe.
Every single one I know has been bent or broken very soon after
delivery, and repeatedly repaired or changed. One I made myself has
been bent during the first half hour after mounting, while I was away
preparing my navigation. So much for the breaking risk. People just
love to step over a fuselage instead of going around.

2) Of course, these ASW probes are placed some distance behind the
wing. You could avoid the breaking problem by placing the probe above
the wing, but I remember distinctly some articles by different TE probe
designers warning against this placement because this would influence
the results negatively, due to the underpressure over the wing. If
Dick's findings disprove this belief, he will have rendered us glider
pilots another great service.


--
stephanevdv
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