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Kollman Raptor
 
Kollman-Rapt
 
The Matt Kollman Raptor is a copy of the Fledge with a composite airframe the same platform as a Fledge. The airfoil was a 2412. It is nearly symetrical with a low pitching moment. The first step was to make the D-tube and load test it. The first D-tube weighed 25 lbs. Jim Marske gave the info and the D-tube was successfully loaded to +7 g's -4g's.
 
The original rigid wing design was scrapped. A new design was started named the Raptor. The Raptor would use the same pitch stable airfoil that's on the Marske Monarch. A new set of D-tubes were completed. These were made of foam and fiberglass with a carbon fiber spar. They weighed 25 lbs each and were load tested to verify the strength.
 
While waiting for the sail it was decided to build a hard wing version of the Raptor. Using Marske Monarch molds for the D-tubes, the D-tubes were made to Monarch specs with the addition of some twist. The D-tubes weighed 32 lbs apiece. Since they were built to Monarch strength they were stronger than necessary for a hang glider. The ribs were made of fiberglass and spruce. There was also a spruce trailing edge. The airframe was covered with heat shrinkable Mylar. The empty weight was 140 lbs.
 
The wing was essentially a Monarch wing swept back with tip rudders. It has a standard control bar with struts and no top rigging. The pilot uses weight shift for pitch. For roll control sliders are used just like on the later Fledge hang gliders.
 
The plan was to aerotow the Raptor and make short hops and feel it out. The first flights were made in spring of 1994. Ten feet of altitude resulted in a long flat glide. The drag rudders were responsive and predictable. After many hops with the highest being 100' it was decided to tow to 5000' and feel it out. The climb up to 5000' was uneventful. After release the first thing to find out pitch stability. Pulling on the bar, the bar pressure built up steadily. There was very little bar movement but substantial bar pressure. Below 15 mph indicated it felt mushy but wouldn't break or fall off to one side. The glider never stalled and broke it just goes into a low speed mush with a high sink rate. Direction control is still there because the drag rudders are still working. The slider controls worked well but it was clear I didn't have enough mechanical advantage on the rudders. When the glider was banked it would tend to tighten up and turn higher unless high side rudder was used. All in all it was a sucessful flight. The Raptor felt stable and controlable. The handling wasn't great but it was acceptable for a first flight. The Raptor prototype weighed 140 lb.
 
After a couple months reworking the rudder cables and playing with different dihedral settings the handling got just right. The Raptor was now roll neutral. That means it stays banked at what ever angle it is set at. Deploying a rudder makes the glider roll in that direction. Once the desired bank angle is achieved the rudder is released. The Raptor will continue to turn at that bank angle. To return to level flight the opposite rudder is applied. This was just like weight shifting.
 
One of the first thing noticed was the Raptor's ability to turn tight and climb in thermals.
 
It was decided to set up a production run of three gliders and 6 D-tubes and hardware needed wasn't available off the shelf. Others wanted collapsible gliders and they wanted smaller gliders. The collapsible was a challenge. The first collapsible glider took almost an hour to put together and it wasn't easy. It also weighed over 130lbs. To get the smaller size wing and still use the same molds the airfoil was modified. Truck tested the pitch curves were well in excess of what the H.G.M.A. required. By changing the size and modifying the aerfoil the dihedral setting was going to need change. This wing was a lot more sensitive to dihedral settings. The sink rate seemed similar but the glide was definitely better than other hang gliders. This wing isn’t able to generate lift as well at lower speeds.

Through repeated set ups and break downs and modifying the design, at 105 lbs. it set up faster and easier. The sail was made by Dick Cheney. Using the original airfoil with less area than the first prototype, this glider flew great from the first flight. The performance seemed even better than the first glider. The only negative to report is bar pressure. Flying above 45 mph is very difficult because of too much bar pressure.
There was a total of 2 hardwings and 5 collapsible gliders built to September 1999. All of the gliders were load tested and passed. The different D-tubes were all constructed using different techniques and the lightest one was 19 lbs.
 
The next redesigned was 15 lbs lighter and with the 20 lb D-tubes for a weight of 75lbs. The amount of twist was reduced by 2 degrees, and the also reflex reduced on the airfoil to lessen bar pressure.
 
The Raptor is now flown by weight shift. The wing is built to cantilever strength with a shifting control bar that is connect to the the rudders. When you shift your weight the control bar shifts deploying the rudders. This is the same system used on other rigid wings except thier cables are connected to spoilers. The beauty of this system is a hang glider pilot gets on it and it flies just like a weight shift glider.
 
The Raptor 2 appeared in 1994.
 
Raptor
Wing area: 15.04 m²
Wing span: 12.49 m
Aspect ratio: 10.5
Hang glider weight: 34 kg
Minimum pilot weight: 59 kg
Maximum pilot weight: 112 kg
Max glide ratio (L/H): 18
Max glide ratio speed: 56 km/h

Raptor 2
Max glide ratio (L/H): 18
 
 
 
 


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