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Old Feb 06, 2015, 01:52 PM
Skip Miller Models
SkipMillerModels's Avatar
United States, CO, Boulder
Joined Dec 2013
39 Posts
Quote:
Originally Posted by Marko Gala View Post

When I kept thinking about its miracle flying weight I realised it is just a bubble which has already splashed. Flying weight is just an illusion. What is really important is wing loading.
It lacks wing area (only 60 sq.dm). For instance: Kappa at 1270 grams has exactly the same wing loading as Perfection or Stork at 1570 grams. The myth of Kappa being the lightest F5J model is busted. Now we have F5J models at the same weight of Kappa but with 14 or 17 additional sq.dm of wing area.

One thing to consider is that in terms of wing loading the Kappa may not be the "lightest" but this is due to the planes high aspect ratio wing. These sorts of wings give the planes legs to range further than the pack. All of these planes are going to thermal well, the question now becomes who can go the furthest and still make it back. There was a similar discussion when the Egida first came out, that plane has since proven itself time and time again.

The plane, as Bohus (our wonderful manufacturer) has mentioned is only 11 months old, our prediction is over the course of the next few years we will see some serious wins with this model. Stay tuned!
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Old Feb 07, 2015, 09:18 AM
Lou
Ground Penetration Tester
United States, VA, Waynesboro
Joined Dec 2005
5,980 Posts
Hmm ... I am curious why the sudden 'hate post' by a Euro pilot that competes and flys a different brand.

Still, I am going to buy one; not because I compete ( I don't ) but because it is cool looking, it is red and I can make that wing loading fly.
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Old Feb 07, 2015, 12:30 PM
HomoDilatus
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Joined Jan 2007
3,763 Posts
Quote:
Originally Posted by Marko Gala View Post
Does anybody know if the ballast is being prepared for Kappa? I can not imagine 1250 gram plane being full competitive... maybe thatīs one of the answers why Kappa has not had any significant success at any big intl. F5J contest in Europe so far.

When I kept thinking about its miracle flying weight I realised it is just a bubble which has already splashed. Flying weight is just an illusion. What is really important is wing loading.
It lacks wing area (only 60 sq.dm). For instance: Kappa at 1270 grams has exactly the same wing loading as Perfection or Stork at 1570 grams. The myth of Kappa being the lightest F5J model is busted. Now we have F5J models at the same weight of Kappa but with 14 or 17 additional sq.dm of wing area.

12 g/sq.dm FAI limit is soon to be reached in F5J. But this piece is not gonna make it.

Happy landings
Marko
Wing loading doesn't mean that much. Span loading is the important factor for minimum sink rate. The Kappa has about a 363g/m span loading, and a Stork 6E even at 1570g (1700g+ seems to be more typical from what I can find) and 3.82m span has about a 411g/m span loading. The Kappa's is about 13% less, which should mean the minimum sink rate is improved, but of course Re and airfoil affects also come into play.

Aspect ratio is the important factor for best L/D. The Kappa has approx. AR = 20.3. I believe the Stork 6 wing area is 74.64dm^2, which would give an AR = 19.6? That is pretty close to the same, and off course Re and airfoil affects again mean that higher AR does not necessarily directly translate to higher L/D.

They are both probably excellent F5J gliders. To focus only on wing loading doesn't really tell anyone which might be the better glider, even if a 1570g Stork 6 was available to everyone.

Kevin
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Old Feb 08, 2015, 02:19 PM
E sailplane thermal hack
USA, CA, Chico
Joined Feb 2011
3,391 Posts
Thank you!! I WAS going to say the same thing but didn't feel I was qualified to do so.
The Kappa is DEFINITELY on my short list of F5J sailplanes I'd like to have.
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