I must admit that I did ask Hans-Jurgen when he would build a hand launch wing when we first started discussing his flying wings. He said that it would be done in future and late in 1996 I received the details for the Co7 Hlg.
Basically it has a parallel chord of 153mm, a span of 1485mm and a sweep of pretty close to 25 degrees. (use the dimensions!)
The wing was designed with the components that were at hand and that is why the prototype ended up with a 500mah battery and some metal geared Volz micro servos. It may have ended up a little lighter if ultra light gear had been available. It has an extremely wide wind range and has been flown quite happily in winds up to 25 metres per second. (at least that fast, memory is foggy). It also catapults quite well, with a hook in the fuselage level with the leading edge.
It is made out of 17-20kg/cubic metre white foam and is covered with two layers of 80gm glass.
One at 90 degrees and another at 45 degrees and has a carbon spar of prefabricated carbon of 7x1 mm. It should be able to be constructed in about 48 hours. Aim for an all up weight of around 500gm.
An interesting thing that was developed on this model was the use of little aluminium sub fins in front of the fin, like a little extension wing. (Sorry for the rude picture) When Hans-Jurgen asked John Yost about calculating the effects of these sub fins his reply was "For Heaven's Sake!" (But imagine it in German)
Hans-Jurgen says that handling wise, the subfins give the best stall behavior he has ever seen in a flying wing.
The section used is the RS004a, again developed by Reinhard Sielemann.
Horst Kropka, the Editor of the fine German Glider Magazine "Aufwind" took this model for a test fly and came back extremely enthusiastic. "You must do an article!" he said, and so it appears on page 24 of Aufwind 1/97.
The wing is one piece, but with a bit of imagination it could be two or even three, which would be my preference. Washout starts at the wing root and ends at the tip with 10 mm or 4 degrees of total washout.
The winglets are 3mm balsa.
Recommended by Hans-Jurgen, is the installation of flaps. They allow the tightest of thermalling and let you "land on a postage stamp." They have a horizontal dimension of 250 mm with the same 30mm width as the elevons.
There is no dihedral or anhedral on this wing.
Again the fuselage is left up to your creativity. Obviously, it must hold the battery and receiver and it would be helpfull if it extended behind the C.G. to help with handlaunching.
This wing has now been made with traditional wing rib construction and has been built down as low as 300gms! Performance is said to be excellent.
Some recent experience from David L.Stone suggests that the Cg may be as much as 10mm further forward than where it is marked on the plan diagram. Tape some lead to the nose for first test flights and move the Cg backwards slowly until it flys to your satisfaction!
Recommended differential is 30% with 40% exponential. You can enclose the antenna in the wing or trail it as a piece of music wire out the back of the fuselage.
