Felix Ruehle, designer of the Exxtacy, announces its successor

We've been sitting on this story for over two months after we got an excited phone call from Johann Posch in late September.  We were sworn to secrecy, and we haven't told anyone, but now we can tell you.

Felix Ruehle, the designer of the Exxtacy, has shown his new rigid wing glider at a show in Germany over the weekend.  Although he didn't say, we are assuming that this is an exposition called "Termik" in Boblingen (near Stutgart), as tracked down earlier by our continental reporter, Bart Doets.

Here's a shot of Felix from last spring at Wallaby Ranch:

The new rigid wing glider is called the ATOS.  It comes in two sizes, the ATOS 145 and the ATOS 125. The larger version is currently being test flown, by Felix, and perhaps others.  You'll find pictures of the ATOS at http://www.davisstraub.com/ATOS.

The number you should bare in mind about the ATOS 145, is its Aspect Ratio - 12.1.  This compares to the AR of the Exxtacy and the IXBO at 10.15, and the small Exxtacy at 9.4.  This is an incredible AR for a hang glider.

There will also be a few other interesting numbers.  Like Max L/D = 19 Vs.  17.5 for the Exxtacy. Minimum sink = 138 ft/min.  Vs.  150 ft/min.  for the Exxtacy.  We are assuming that this assumes a hook in weight for the pilot at 200 lbs. We also believe these numbers to be calculated numbers, and not test results.  We await confirmation.

How about glider weight out of the bag at 73 lbs?  This compares with the Exxtacy at 95 lbs.  Now the Flight Design literature on the Exxtacy stated that it weighed 85 lbs, so we hope that Felix isn't using the Flight Design way of weighing things.

Sail area is 146 sq.  ft., and the span is 42 ft.  The glider packs "down" to 5.8 inches, by 48 inches by 20 feet.  We are not clear on this and have asked Felix for more information.  The Exxtacy packs down to 9"x20"x20'.  This seems to indicate that the sail isn't packed around the D-Cells.

The pilot weight range looks to be the same as the Exxtacy 160 (although total weight in different due to the lower weight of the ATOS 145).  This hook in weight range is 125 to 258 pounds.  If the weight ranges for hook in weight are the same, this would indicate that the ATOS 145 is indeed 23 pounds lighter then the Exxtacy 160.

These weight range numbers also make you wonder why anyone would want the ATOS 145, except pilots that wanted a lighter weight glider.  The ATOS 145 weighs less then the Exxtacy 135.

Here are the specs as Felix sent them to me:

Technical Data ATOS 145
Span 12.81m (42ft)
Aspect Area 12.1
Sail Area 13.6 (146ft)
Weight 33kg (73lbs)
Packing Size 5.8x48x20
Take Off Weight 90-150kg (198-331)
L/D 19
Min.  Sink 0.7 (138ft/min)

Felix is claiming that the packing length of the ATOS 145 is less then the Exxtacy 160.  Comparing his specifications to the Exxtacy 160 specifications don't show this, so we will follow up on this.

Felix also states that the max L/D improvement is a conservative calculation because it doesn't account for the better finish on the sail.  He also states, "However, 19:1 can be reached only by an optimized pilot position.  With a higher drag of the Pilot the difference in L/D with respect to the Exxtacy will be less but, still remarkable."

Felix was very concerned about pilot orientation when testing the Exxtacy.  You have to be parallel to the apparent wind  with your arms tucked next to your sides to get the higher glide ratios.

He also says, "BTW, these numbers are not dramatic, at least not the step from topless to Exxtacy.  Of course, we are now in the refinement phase of a design type."

Felix goes on, "There are more advantages.  Especially while flying in thermals with high bank a low induced drag is an important criteria for a good climbing.  This is improved due to the higher aspect ratio and the shape of the tip and a optimized lift distribution.

"Further advantages are a better handling, which is much more direct with a shorter roll ratio.  This is the result of the very light outer wing in combination with a new spoiler geometry and the changed wing shape. I
know it sounds a little bit too much and some Exxtacy owners already asked me "could it be that much better" but that's  also my impression after the first flights."

We asked him:

How are you able to significantly reduce the size of the glider (8%), and decrease the minimum sink rate and increase the max.  L/D?  That is how did you make the glider more efficient?  Does it still have a constant cord?  Does it have a different profile/camber?  Different material?

Felix answered:

"The Exxtacy was designed with a constant chord to keep the production costs low.  The development effort of the ATOS is higher, because the airfoils are designed for the local angle of attack which requires different moulds for ribs and spar.  The new design of the flap is responsible, too, for better sinking.

"The sail material is different and the finish of the sail is better too, due to the experience of Bernd Weber who designed the sails for Thalhofer, the last UP HG's and continued the production of the Pegasus sails after I stopped it, the finish is know very nice.  The sail will be produced at Icaro which will give us an additional Know How input."

Now, that's big news.  We had heard that Gianni (at Icaro 2000) had stopped the Lumina project after its design failures, and now he is working with Felix, who has a proven track record designing the best rigid wing hang gliders.  Comnbine this with the manufacturer of the "best" topless gliders, and things get real interesting

We asked Felix:

Will the glider be as strong at the Exxtacy?

"The breaking load of the Ixbo was 780 kg (according to my last information) in comparison to the Exxtacy (1080kg DHV test).  This was quite enough but with small changes it was possible to increase the max.  load further more (+20%). In order to optimize the structure, I did load test's at the DHV car with strain gauges at critical locations.  This was possible thanks to the DLR (German Research Institute) where I still work part time and which gives me a very good  relation between theory and practice.

"The ATOS has the same designed loads as the Exxtacy."

Oh man, more interesting information. First, that the beefy looking Ixbo didn't have the strength of the Exxtacy.  Second, that the ATOS and the Exxtacy will have the same strength.  And, third, the thought occurs, why not 20% better?

BTW, the projected weight of the ATOS 125 = 68 lbs.

Felix says he will be in Florida for at least one of the competitions this spring.  We also hear rumors that the ATOS will be at the USHGA membership meeting in Knoxville, on February 26,27,28th.

We asked Felix:

We heard that you've reduced the setup time by 30%.  How have you done this?  What is the rib setup?

Felix stated:

"The set up is changed, more comfortable and faster.  E.g.  clean trailing edge by  using new fittings."

Also we asked:

We heard that you've significantly redesigned the spoileron and flap bags.  What is the result of this work and what have you done?

"We did many calculation and test-flights you can see a part of the result at the picture."

Felix said there are more details that will come out later about this.

We asked:

Are you working with a new manufacturer? We hear that the D-cells will be made elsewhere and the gliders assembled in Germany.  True? Is the manufacturer reliable?  Do they have the experience?  Can they put out spare parts?

Felix states:

"The name of the new Company is Aeronautic Innovation F. Rühle and Partner.  Due to bad experience with Ukraine companies the gliders will be assembled in Germany.  The people who assemble the glider are members of the earlier Thalhofer Company, were the experience of more than 20 years hanglider manufacturing can be used.  "

"One additional composite specialist will be responsible for checking and for maintenance of the composite parts. The parts will be manufactured in Germany and other countries."

"Each glider will have a sticker with 'designed by AIR'.  One, but not exclusive distributor is Icaro2000.  This means the customer can buy the glider at AIR, Icaro or an other manufacturer.  The same spar parts e.g.  can be bought at Icaro or AIR.  The advantage of this strategy is, that we get a very good service all over the world, a high number of gliders which reduces the prices, concentrate the experiences and makes high reliability and further development possible.  And we will get some new competition pilots.  I hope that you are in good shape!"

Simply amazing!  Icaro will be a distributor.  Will this mean that AV8 is a US distributor?  What about Lookout Flight Park with Matt Tabor and David Glover - they're right next to Knoxville?  Does this mean that Larry Tudor will be flying an ATOS 145?  How about Glen Volk and the other Icaro pilots?  Manfred?

We asked Felix about his former relationship with Flight Design.  We had heard that he broke off with Flight Design late last spring after the Atlantic Coast Championship.

Felix said:

"Yes I had a contract with Matthias Betsch that he produces the glider and pays  me a licence fee.  Matthias sold the gliders for 200DM from one company to an other.  From this 200DM wholesale price I got the per cent for the Licence.  After many remainders I received the first bill directly after the ACC.  Nobody knows how this works and it is up to the lawyers to find out if this is correct or if I have to pay the lawyer's costs, too.  A former worker has now received the money after a process, another one is still waiting since years (constructor of CT).  "

200 DM is not a lot of money for a hang glider.  I think what Felix is saying here is that Matthias played a bit fast a loose with the bookkeeping.  By selling glider at ridiculous prices from one of his companies to another (if this is in fact the case), he made Felix's license worthless.

We asked Felix:

We also heard that workers were leaving the Flight Design Ukraine factory to work for Aeros.

Felix said:

I don't know if people are going to Aeros, but many workers have left the company, that's right.

We asked Felix about the Exxtacy and trikes:

What are your thoughts on attaching a light weight trike to the Exxtacy or to your new glider.  Is the keel strong enough for a 100 lbs trike?  Should I beef it up? How can I?  Are you thinking about the use of the wing for light trikes?

Felix states:

"It should be strong enough.  Dangerous can be dynamical loads which require an additional safety factor so that I wouldn't recommend it to anybody, as it is not tested.  It is very important how the trike is mounted to the keel to keep the dynamical loads low."

We asked Felix:

Are there other competitors out there?  We hear of the Stealth version coming out very soon. We've seen the pictures of the Lumina.  We haven't heard much about the Top Secret lately.  How do you plan to compete (other than by being light years ahead)?

Felix said:

"Icaro has stopped the Lumina Project, the Pegasus clone from La Mouette has stopped too.  Jos Guggenmos will build one, I gave him many inputs because I know that he will not make a copy. 

"Matthias tells us he has a new Glider "Ghostbouster" but he doesn't want to introduce it, as he is afraid that some body will copy it.  Maybe he hasn't seen the necessary details on the ATOS, right now.  He has created this story some days before the exhibition when he heard about the ATOS project."