Friday, December 13, 2019

Interview with OZONE R&D Mr Luc Armant ( 12/12/2019 )





Hi,
I asked OZONE R&D, Mr. Luc Armant, a few questions concerning some interesting future designs.
Please find below his kind answers.

Ziad: 1- Will the new Delta 4 be certified this spring?

LUC ARMANT: Delta4. We aim to certify it this spring. However, we only release a glider once we are fully happy with it, so we can never be sure of the date. Remember that it's evolving research work, weather conditions, humans, politics. So there is a lot of uncertainty in the equation. The only thing sure is that an Ozone paraglider model is only released once it's superior to the previous model.


Z: 2- Will it have a moderate aspect ratio? Like its predecessor?

LUC A: Delta4, moderate aspect ratio. Yes. I believe it's still possible to have the best performing glider in the C category while maintaining relatively low aspect ratio, which helps for safety and manageability.


Z: 3- Will the use of the collapse line be used in the new C class? And on the D4?

LUC A: Collapse lines. There is an amendment to the current norm that needs to go through a formal vote. If I understood correctly and if it's accepted, it will only be in an application for certification around June 2020. 


Z: 4- Can you please comment on the strong points of Zeno 2 you are focusing on? Will it have sharper Handling?

LUC A: Zeno2. of course nice and sharp handling is important. Zeno1 does not have bad handling, but it is very sensitive to trimming, so the pilot needs to trim his Zeno1 regularly to make sure it's at his best. I personally love the Zeno handling when the trimming is set to slightly positive (per group, from 1 to 3 around 4-10-5mm)



Z: 5- Will the Zeno 2 get the same sizes as the Delta Rush series? Example 75-95…etc. Or will it follow the Zeno 1 pattern? 70-90…85-100…etc.

LUC A: For the moment, I'm making research prototypes in the same ML size than the Zeno1, for comparison sake, but we can adjust the size once we're happy with the final result. We'll see. 


Z: IMHO, and personal feel, I think seat board harnesses got lost over time, and there’s a big gap in pilot feel that was lost with them.
Seatless harnesses have great back support but lack precision versus the seat harness ones.
6- Will Ozone invest in a 3 kg, or 5 kg state board harness series with a back fairing?

LUC A: light seat board harness with back fairing. That's the Forza2 project. work on progress. 


Z: 7- What’s your personal philosophy toward the future of 2 liner gliders? Will the internal structure evolve in such a way, that even lower aspect ratio gliders could have fewer attachment points and still be very solid and homogenous in rough air? Is my thinking far a bit? From your perspective?

LUC A: 2 liner gliders future. I think that there are many things possible in the future. It's been only 10 years of developments by only a few companies until now. But I think interest and developments will grow up for this sort of design. 


Z: 8- As the products, being lighter, (harness and glider), Even a 70 kilos pilot will find himself on an XS or S glider…. With 80 or 85 all up weight. Will art be possible for a manufacturer to produce special sizes with special line diameters for this class in order to maintain the gap of performance with the bigger sizes? Or will it be too costly?


LUC A: Yes, it's possible for a manufacturer to produce a special size with a smaller line diameter on smaller sizes. To do so, it's basically costing the manufacturer a complete load test certification (one or two prototypes wasted + certification cost), so it's a question of how much the manufacturer expects to sell off one particular size and how much it may increase the performance. 
However, please note that even after adapting line diameter to match at best the lighter weight, most of the gap performance will still be there. Several scale effect phenomena are responsible for that. I see so many small pilots unhappy about that, but unaware of the real reasons that it's always good to remind the physics behind. 
a- line strength is related to line section, while line drag is related to line diameter. So when you multiply a line diameter by 2, the strength is multiplied by 4, while the drag is only multiplied by 2. That's an advantage for bigger sizes. 
b- stitching size, and stitching surface imperfection size are constant. The smaller the size, the bigger the relative drag. 
c- Reynolds number. also, a scale effect that affects flight performance down for smaller sizes, especially for the thick profiles used in paragliders. 
d- pilot+harness drag (a very big part of the total drag). Pilot+harness drag does not increase as much as the weight when you increase the pilot's weight. Another scale effect that can be simplified as Pilot+harness being a sphere. When you increase the diameter of a sphere by 2, its volume, mass or weight increase by 8, while it's frontal area and drag only increase by 4. 


Thank you very much for your kind answers!
Best regards,
Ziad

No comments:

Post a Comment

Note: Only a member of this blog may post a comment.