How does the Raptor fly compared to regular flex wings?
The Raptor has a very responsive control system combined with a fast roll rate. Most pilots over controled at first until realizing how little effort is needed. Flex wing pilots who made there first flight on the Raptor had little problem adapting.
What's the difference between the Raptor and other rigid wings?
Most rigids I have seen use spoiler controls and have a flap. The flap is made possible by sweeping and twisting the wing. This added pitch stability at the tips offsets the pitch instability created by deploying flap. This as an elegant solution. It gives a thick slow speed airfoil for slow flight and a thinner airfoil for high speed flight.
The Raptor takes a different approach. Use a pitch stable airfoil over the entire wing. Reduce sweep and twist to a minimum. What's the minimum? For twist it's the least required to prevent tip stalls. Twist hurts high speed performance.
For sweep that's where it gets interesting. Jim Marskes wings have shown pitch stability is possible using the right airfoil. Sweep isn't necessary for pitch stability however a wing without sweep has very little directional stability requiring a large rudder. Also on a wing with no sweep the hook in point for the pilot differs greatly from where the empty balance point on the wing alone. Why does this matter? Because the pilot is hanging from the wing not firmly attached. If the pilot encounters negative G load and the hang strap goes slack The wing alone would be unstable.
So the design philosophy of the Raptor was to use a tapered D-tube to reduce needed sweep. Then set the sweep so the hook in point converges with the balance point of the empty glider. The sweep isn't high enough for good directional stability so Tip rudders supplement it.
What materials are used in Raptor construction?
Raptors use Graphlite rods for spars and high stress areas. The D-tubes do not use core material and are solid composite laminates. D-tubes have been made from fiberglass, carbon fiber and Kevlar and various combinations. Kevlar seems the best suited material for D-tubes.
Ribs are combination of wood cap strips bonded to a composite panel. Hard wings use wood trailing edge. Collapsible wings use standard sailcloth. Ribs use the same construction as hard wing but with additional reinforcements added.
Is the Raptor certified ?
The Raptor is not certified by the HGMA. There are no plans to certify it at this time.
How do you load test wings?
The wing is suspended or supported upside down for positive load test. Then weight is added to simulate flight loads. Raptors are tested for positive and negative 5G @ 300lb hook in. Therefore 1500 lbs of weight is added to wing across the span. I usually test the D-tubes alone since they are the main structural component. The load test of the Cantilever R2r. With no load.
Full load. Willie is pushing down on tip until other tip is airborne.
Is there a tail available for the Raptor?
There are no plans to add a horizontal tail to the Raptor. It doesn't need one. It is recommended that a keel fin be used for additional direction stability.
Has the Raptor been spin tested? How easy does it spin?
I was able to push the R1 into a spin by first stalling in in a moderate turn then denying recovery from stall. Basically when the stall hits the nose will drop and glider will recover. If you keep pushing out and deny the recovery and push it far enough it will spin. I never let the spin fully develop and didn't rotate more than half turn. The recovery was easy let bar return to trim and apply opposite rudder. Easy but scary. The glider would pitch nose down and pick up speed fast. Once the reflex kicked in it would level out. The scary thing was it could use up 200 to 300' of altitude in the blink of an eye.
There has been one accidental spin in the Raptor. It happened during a test flight on the second R1. Shortly after launching on an air tow I discovered my hang point was way off. To maintain flying speed required a lot of back pressure on the control bar. I was eager to test this wing so decided to tow to altitude 3000' anyway. The tow went fine. I was able to test roll stability and turn reversals on wing. Everything felt fine except for problem with trim speed. After driving around for a while to loose altitude I made a high banked 180 to line up with landing field. I also did something incredibly stupid. I let the bar go out to trim. It felt like the glider flared to a stop while banked 45 degrees. When I realized what I done it was too late The glider already entered a spin. I only had about 100' not enough room to recover. I had spun tested 1/4 scale models of the Raptor and they spun flat and fast like a maple seed. So I decided to push out even more. The theory was the faster I spun The slower the descent rate. The result is I got three complete revolutions in before impact. I suffered a broken wrist and spent a few nights in the hospital. Did the theory of spin faster pay off? I don't know but did learn one very important lesson. Do not fly a glider if the trim speed isn't set right land it and fix it.
Landing
Glide and slow down till the glider is on the verge of a stall and then flair hard. The flair window is not that critical you can flair going too fast and if you jam it the glider turns into a lot of frontal area and stops/drops. I have had a lot of good no step landing and also pulled off some nice no wind landings. I will admit that I fly with wheels and have been know to use them when I mess up. When you see that your down wind and your flying a 100+ pound wing that you have sunk all your money and soul into you might make the same decision. Wheel landings are a no brainer.
Conclusion /3/98, Mark Stump
Raptor status from my perspective as having flown the three collapsible versions. I have been flying hang gliders since 1975 and pretty much exclusively on ridged wings since 1980. I have around 60 hrs airtime on the various Raptors my comments will be basically about the three flights I had on the latest version. In August Matt Kollman brought down the latest version of the Raptor to Arkansas so I would get off his back about letting me get some time on it before it had to go to it's owner in California. Matt was also wanting to see the glider foot launched off a mtn and foot landed in addition to seeing how the glider performed in comparison to the Exxtacy which we consider to be a bench mark to gauge our performance. LAUNCHING This glider weighs about 105 lb.. This is noticeably better that the 118lb prototypes I have been flying but I'm still anxiously waiting for the under 100lb wing! I like the way the raptor ground handles with the ridge control bar it's easy to stabilize the glider on launch and it also has good static balance. What I have found is that the Raptor gets flying very quickly and it doesn't have any tendency to drop a wing. Some of this is probably due to it's weight and the span, it takes a lot of air to throw it out of position.
Flying
The Raptor likes to fly around 23-25mph. You can fly it as slow as 16-18 mph but you don't have much if any roll authority at these slow speeds. It is reluctant to stall and gives you lots of feed back of an impending stall. The base bar pushes back real hard as you then start to feel the air separate from the top of the wing. It tracks straight at all speeds and doesn't yaw around. It just feels real stable and solid. Thermaling is very easy just deploy the rudder to get in the desired bank and then come off the rudder. The glider will pretty much stay in the bank as long as is not too steep. If the bank is too shallow this wing has a real strong tendency to get leveled out and with it being 40' span if your flying slow it will take some time to get it brought around and re centered up in the thermal. The sink rate in a moderate to steep bank is what's noticeable. This wing climbs strong in a 40+deg bank. What's also amazing is that you can push out till it gets so quiet you hear no wind noise, just the sound of your vario screaming. I continually land and have experienced noticeably higher climb rates than anyone else. Glide! This wing glides side by side with the Exxtacy at the speeds it(the Raptor) can fly. This is the kicker... Your asking yourself where's the bad news, well here it is. It's hard to get this wing going fast. What has been affecting our overall performance is the wing has excessive bar pressure above 35mph. Matt Kollman and Jim Marske have determined that this pressure is being caused by too much twist. We have 6deg of twist we are currently modifying the two prototypes to have 4deg of twist.
When we put theses gliders on the USHGA truck test rig owned by Mark West he stated we had one of the strongest pitch curves he had every seen. We well exceeded the **** requirements in pitch. So this gives us quiet a bit of room to lower the twist and speed the Raptor up. From all I've been told this is going to help every aspect of our performance. From lowering our stall speed ,reducing our sink rate even further and speeding up where we can utilize the awesome glide we have when we need to run. I look forward to finding out if this is true! Landing The Raptor's have drag rudders these come in very handy when your landing in a restricted field. Just deploy them both and pull the bar in, the glider will descend very steeply to the point you want to enter the field at. At this point come off the rudders,
The Raptor 1999. The glider is evolving but not as fast as it should because of very limited resources(dollars). We have a very high performance foot launchable wing that is fun to fly. We know what changes we are going to make over this winter and feel very confident that the glider that emerges next spring will be one of the top performing foot launchable wings in the world. All we have to do is have the ability to go faster we already do everything else real well. If this proves to be the case then We will have the delima of how to get into production.
