Libelle

Mr. Quebec and Mike thank you. I had looked at both those pages. I had considered the Damaged Libelle I found a good candidate for the Schumman Mods being that extensive repairs would be needed anyhow and why not add those mods while I was at it. I would find it hard to modify a classic glass ship like the Libelle. I would want to keep it factory and do a restoration but not major external modifications. The Schumann mods the primary being the wing would be a moot point on the 201 as they have the Wortmann was it wing already correct? In respect to the turbulence Schumann claimed as being the entire undersurface of the wing perhaps a turbulator tape applied in the right place on the under surface would provide a better flow. Maybe the same tapes could be applied to the nose section with improved results for higher speed flight. I'm not concerned with owning a Libelle to fly fast in competition, I'd be happy with having such a beautiful ship to fly and accept it for what it is, limitations on speed being what they are. What I'm understanding is the 301s spoilers were half as effective as the 201s yet it had flaps which compensate and bring it to a similar ability as the 201 or allow slightly better landing performance? The 201 had a higher performance airfoil standard? Anything else I'm missing?

The 201 airfoil is not higher performance than the 301.

Wikipedia Libelle entry isn't necessarily correct. I read that the 201 had a Wortmann airfoil whereas the article written by Schumann stated that the 301 airfoil was a Heutter airfoil. Maybe the thing is the 201 has the Heutter airfoil that has been mistakenly called a Wortmann in the Wiki entry.

Maybe mistaken in the Wiki entry and otherwise? Glasfaser must be able to say what the true airfoil section is. From what I'm gathering the 201 and 301 have the same airfoil yet if Wil Schuemann is correct in his assertions the both mentioned Libelle have a Heutter airfoil and not a Wortmann as is seemingly commonly thought.

If it's any help, I obtained a set of laser cut templates for the Libelle 201b from Streifeneder. They are all marked as FX 66-17AII for all wing stations. The FX series would be a Wortman airfoil.

Mark Guay

I have built a number of wing wheels and WingRiggers for both the 201 and 301. I can definitely say that the airfoils are very different. The 201 is thicker, with more curvature on the bottom.

The 301 aerofoil is a lot thinner & designed for flaps so very different.

I have spoken to Christian Streifeneder regarding turbulators, he has pointed out that there may be a case for putting them on the top surface of the wing, but then it would be difficult to wash the wings. He's not convinced they are effective on the underside.

By the way, there is no H in 201 (regardless of what Wikipedia says) - the H in H301 denotes Hutter who was involved in it's design, but the 201 did not.

Cheers,
Nick.

On Sun, 24 Jun 2018 17:37:23 -0700, fthacorpgov wrote:

In respect to the turbulence
Schumann claimed as being the entire undersurface of the wing perhaps a
turbulator tape applied in the right place on the under surface would
provide a better flow.

My Libelle, an early H.201 with balsa surfaces and both top and bottom
surface brakes, has lower surface turbulation. This is zigzag tape a bit
forward from where the undercambered rear part of the lower surface
starts. It was fitted when I bought it but I'm fairly certain the tape
and instructions were supplied by Glasfaser. Mine runs comfortably at 80
kts without much height loss. I do not have root fairings fitted: would
like fairings but I don't think the fuselage would fit in the trailer
with them on - very narrow trailer.


--
Martin | martin at
Gregorie | gregorie dot org