Posts to the Skywacker List: These were written for my local hang gliding/paragliding list. They start with my first Mosquito demo flight and describe my experiences learning to fly a Powered Harness.
I've been thinking about the Mosquito motor harness for over a year now. Today I went over to demo one at Blue Sky (Steve Wendt - near Richmond). They came out with a new model (NRG) late last summer, but Steve still had the old one. The new one uses the same power train etc, but the harness has been cleaned up and is easier to get into, among other things.
After going all over the controls and attaching it to the glider Steve took a flight to show how it was done. It looked pretty easy. After he landed again we hung the harness up and adjusted it to fit me (the old model is one-size-fits-all, the new one comes in two sizes). The old harness is not easy to get into, and you almost have to have a helper. I'm told the new model has all buckles for the leg loops, etc so it is much easier to get into. Once you are in it you can only walk forward, otherwise the skids can dig in and fold under.
I did a lot of searching on the internet to see what I could find out about other people's experiences. Between what I read there and what Steve told me - these are some of the things you need to know:
Forget about what you know about bar position on your glider. They say that the bar trims further down your body than you are used to. Yes and no. The weight of the motor and prop behind you mean that the combined CG of you in your harness is further back. The glider itself trims where it always does, but because your CG is further back you swing further forward through the control bar. But from a flying perspective, the bar is indeed further back than you are used to - maybe 6 inches or so in normal flight. With power on you are pushed further forward through the control frame, so the bar may seem to trim a foot or more back of where you are used to under full power. The important thing is to just let the bar trim to where it wants to when you are under power.
You need to think about thrust lines while under power. Basically, this just means keeping your body parallel with the keel - save those turns where you lead with your feet for when the power is off. They say that leading with your feet when making a turn under power will tend to make it want to wrap up tighter. I made only gradual turns, so I never even noticed this. I could tell that changing my body angle did effect the way the glider wants to turn, but if you keep the turns mellow even full power turns didn't seem to be very difficult.
Every comment I've read says that landing with the Mosquito is at least as easy as landing without it, and most people were of the opinion that it is actually easier. You come in on final and wait till you feel the skids starting to drag behind you, then wait a second or so and flare normally, only not as hard. Because of your forward position you have more flare authority than you are used to, and the skids dragging help pull you to a stop. My experience today agrees with those opinions. The demo was on a 195 Falcon, and it was exceedingly easy to land with the Mosquito. I imagine my normal glider won't be too much harder.
The most important part seems to be to let the glider control the angle of attack on take-off. I have heard it said a number of times that if you try to push out on the bar you will go into a mush mode - after which the "p factor" (gyroscopic forces from the rotating prop) takes over and tries to lock you into a right turn. The really cool thing about this unit is that you are controlling the power with a mouth throttle on takeoff. If the power starts causing funky things to happen simply release your bite on the throttle and you are back to flying your old familiar hang glider - straighten things out if you are high enough and reapply power, otherwise just land and try again.
For my first flight the wind was blowing at maybe 3 to 5 max on a cloudy morning. You run the engine up holding back against the thrust, just to warm the engine briefly and make sure you've bled all the bubbles out of the gas line. Then just start running, letting the engine push you and letting the glider have full control of the pitch once you get moving.
It seems like I was off the ground in a half dozen steps or less - no p factor or turn tendency or anything like that. About 20 feet off the ground I started to go prone and the engine quit (I hit the kill switch with my elbow). It was no problem, I just pulled myself back upright and settled down to a normal, easy, hang glider landing.
After checking to make sure that was the problem, a couple of tugs on the starter rope and I was off again. This launch was equally easy, and this time I didn't hit the switch accidentally. Climb rate seemed very good right off the deck, then seemed to become more variable - probably just the air I was in. I didn't have any instruments, but it seemed like at times I would be climbing pretty rapidly and other times not climbing very fast, although I couldn't hear or feel any difference in the engine. They claim a max climb rate of 400 fpm, with a range of 200-400 fpm. I was certainly getting something within that range, probably at least 250-300 on average, and maybe higher.
I'm guessing I got up to 4-500 feet in less than two minutes, and not all of that was at full power. I tried making turns with different power levels, and it all seemed pretty straight forward if you kept the turns gentle. If something got a bit stiff I'd just ease off on the throttle for a moment and it responded just like a regular hang glider again. My conclusion was the power was certainly adequate for someone of my weight (170-175) - and the distributor, who is well over 200 lbs, says it gets him up OK too. I envision using this mainly to fly mountains close to home that don't have a launch. Whether it takes me 5 minutes or 10 to climb up to where I can shut the engine off and soar a previously inaccessible site doesn't really make that much difference.
But you wouldn't want to try taking off from a small field where you had to depend on immediately crossing a 200 ft row of trees.
Once you are at a safe altitude you zip up the pod harness, which pulls the skids forward. Then you grab each one and attach it to a clip on the side of your harness so that they are completely streamlined. I never bothered with this step while flying (I tried it hanging in the simulator on the ground) - but Steve said that most times, when you are ready to land, you can just unclip the skids and the air resistance on them will pull them back into place and unzip your harness for you as well.
For landing the preferred method is to shut off the engine and lock the prop in a horizontal position. The prop lock is just a tab on the harness that you pull. The prop will normally freewheel, and you may have to pull and release the brake a couple of times to get the prop where you want it. You could land with the engine running and the skids will keep the propellor off the ground - but the horizontal locked position is your best insurance for not getting a painful injury in your wallet if you have a less than perfect landing (that really slick 1 lb carbon fiber prop costs $500 to replace).
After I landed I talked Steve into letting me have one more flight. The wind had picked up a tiny bit, and I got off the ground really quickly on the third takeoff. I just made that a short flight because it was the takeoffs that I had been concerned about. After 3 out of 3 being just fine I was writing Steve a deposit check!
The Mosquito was everything I hoped it would be. While the engine does make a lot of noise, it really wasn't nearly as loud as I had expected it to be. Takeoffs were actually very easy, and I would say much, much, less stressful than a towing launch from a truck! You don't have nearly the forces under power that you have from a tow, and if something goes wrong you don't have to go reaching for a release. In fact, unless you really let things get out of hand, you probably don't even have to start over again like you would with a released tow - just release the throttle until you get straightened out and then reapply power.
Steve says he has had quite a few people demo the Mosquito, and only one guy had any problems - and his was a case of poor, nose high launch technique (right turn on climb, didn't even take out a downtube, but he did have to buy a new prop :( ). I had heard some stories about scary launches at Sun & Fun last year (turns out that was a Doodlebug) which sort of scared me off for awhile, but my impression now is that this is a really neat toy! Sort of like a fairy godmother sprinkled some dust and said, OK kid, now you can go fly your hang glider out of a flat field!
Actually, the year wait really paid off - the new model looks like it will be a great improvement. Besides the harness improvements, the controls have been more carefully integrated into the harness instead of hanging on the outside (like that kill switch), the mouth throttle has been improved for use with full face helmets, and even the parachute container has an integrated switch so the engine is automatically shut off if you throw your chute.
They ain't cheap - this will come in at about $5k. But if $ are a problem you can probably pick up one of the older models pretty cheap.
It should fly as well, just not be as convenient. I talked to a guy who had an add in the most recent HG magazine - he had one for sale for $3500 complete with a brand new High Energy parachute, and it had never been flown (3 guys bought 3 of them together, and then they all ended up taking turns flying just one of them). Once people see how slick the new ones are I imagine the older ones will be out there begging to be bought.
Mine should be here in about 3 weeks or so - I'm feeling like a kid waiting for Christmas morning to get here!
This is an excellent web page describing the differences in bar
position
between a Mosquito and regular hang gliding:
http://www.bmaa.org/powhang.htm
Other stuff to know: you do have to make one modification to your glider in order to use the Mosquito - the end of the keel must be cut off. The specs say it should be cut no further than 47" behind your hang point. You can use a sleeve and a pin to put it back on for set-up and when not using the Mosquito. You also have to attach loops to the junction of your sidewires and leading edges - these are for attaching side "limit lines" when you hook up the Mosquito - to keep you from moving the rear of the harness too far sideways and getting the prop into the sail.
The 47" distance should not be a problem with most gliders (it looks like I could get it down to 43 or 44 inches on mine), but some lower aspect ratio gliders, like the 195 Falcon Steve Wendt has, require more work. For that glider the 47" was actually cutting off the keel in front of where the wires attach. He had to shorten the upper and lower wires and cross-bar cable in order to move the cable attachment point forward.
If you want to actually see (and hear) one take off - checkout the
"takeoff.avi"
file (near the bottom of the page) at:
http://fly.to/powered-hang-glider
After 6 weeks that seemed like 6 months my Mosquito NRG finally came in. And there I was, picking it up on Friday the 13th. What could go wrong? Well, rain for one. A slow moving front was parked over us and every time it seemed like the sky was getting brighter the rain would start again.
So we spent a couple of hours in the hangar going over the harness and controls, installing the parachute, and starting the engine. The NRG has a lot of changes from the older Mosquito. The biggest one is that it is now front opening. Instead of having to try to climb in through a small opening in the front, you simply back up to it, slip your arms through the shoulder straps, cinch the waist belt, buckle the leg straps, and then shut the front of the harness with two more buckles. The hardware and buckles appear to be first class stuff. This harness also has a carbon backplate in it which is attached through a pulley system so it is very easy to go between fully upright and prone positions. There is also a angle-of-dangle adjustment which operates with a jam cleat on one side. The control cables, fuel line, etc are on top of the carbon back plate and hidden by a cover which attaches with velcro. Makes a clean looking harness, but everything is easy to get to. The mouth throttle design has been improved, and it is attached to a bungy which pulls it back into your left shoulder strap when you are not using it. The throttle control has been completely reworked. Instead of the bicycle gear shifter control on the side of the harness (which could get bumped or snagged on wires) the new arrangement is at the right shoulder. It consists of two balls attached to cables. One ball is large and donut shaped - pulling this decreases the throttle. The second line runs through the donut hole and is attached to a smaller ball - this increases the throttle. This arrangement allows you to easily control the throttle without having to look at it, and it is easy to find and gives precise control. There is no kill switch anymore (the one that I bumped off on my first flight) - the choke is used to stop the engine (which also makes it easier to start next time). There is still an emergency switch. It is basically an insulated alligator clip with a piece of webbing separating the jaws. Pulling the webbing out kills the engine. This is located inside the parachute compartment and terminates in a small red handle on the outside of the harness, just above the parachute handle. You can pull the small handle to just kill the engine. Or when you pull your parachute to throw it, that also kills the engine. Either way you have to open up the parachute compartment to reset the switch.
At one point it looked like the rain had stopped for awhile, so I set up my glider. Even if I couldn't fly it, it would be good to check hang strap length and get the side limit lines adjusted. It started raining again before I had the glider completely assembled, but not hard, so we proceeded to get the lines adjusted, etc. I kept listening to the weather radio - the rain was supposed to stop by mid-afternoon - of course it could be blown out then, too. I kept hoping for a window between the rain and the wind.
At one point I noticed it hadn't been raining for a little while. The wind was pretty light, maybe 3-5 with peaks of 7 or 8. We took towels and dried off the leading edges and I started feeling that little bit of anxiety that always precedes a launch - especially when it is something new and different. I got moved into position, cinched the waist belt tighter (that is about the only thing that controls the direction of the harness until you can get your legs up into the harness) and started the engine. I ran it up again to make sure it was running good at full throttle, that the engine was warm, and that the bubbles had been bled from the fuel line. I also walked forward a few steps directly into the wind to make sure the harness was lined up directly behind me.
I bit down on the throttle and started to run. For some reason it just feels different to run on flat ground with a glider heavy on your shoulders. I guess a mountain launch has a downhill component and as the pilot goes downhill the glider seems to come off the shoulders much faster. After a few steps the glider rose up and carried itself - leaving just a very brief awkward moment between when it was resting on my shoulders and when it was carrying itself. For that brief moment I didn't feel like I would have much control of it if a wing got high - I guess that is where you just spit the throttle and try again. Anyhow, nothing ever happened during the three flights I took, and with more wind perhaps it would not even be noticeable. Once the glider was carrying itself I remembered some advice from other pilots to "try to keep it on the ground" in order to prevent taking off with too high a nose angle. So I pulled the bar in a bit, but that didn't seem to matter, my feet were off the ground in another step or three. I pulled in some more while I quickly got my legs back up into the pod. Even with the pulling in (the bar was probably close to my belt) climbing was not a problem.
Climbing and turns were not a problem as long as I kept the bar pulled in. At one point I sort of pushed the bar out a bit in a turn and things got real stiff and hard to control - then I realized what I was doing and pulled back in and it all got easier again. This was a new engine, and they recommend not running it at full throttle for more than 5 minutes at a time until it has some time on it. Being a bit cautious, I backed off the throttle as soon as I felt I had sufficient altitude. I then set the throttle on my shoulder and put away the mouth throttle. Once I got up to 7-800 feet I decided to try zipping up the harness. It was not difficult, but I couldn't figure out how to do it without briefly taking both hands off the control bar. Zipping up the harness with one hand is no problem, but the legs also need to be snapped into place once the harness is zipped up. The problem is, if you let go of the zipper pull to grab a leg, the air resistance on the legs pulls them back and starts unzipping your harness again! So I had to hold the zipper pull with one hand while I reached back and grabbed a leg with the other. Once I had the leg I could put the zipper pull hand on the bar again while I snapped the leg into place. This was all it took to hold things stable, and then I could reach back with the other hand and snap the other leg into place.
Even with running at various throttle settings and sort of wanging around trying to get the harness zipped up I had climbed to about 1000 over in around 5 minutes. I had originally intended to climb up pretty high to play around, but things started getting a bit turbulent. I wondered if maybe something funky with the frontal passage was happening, so I decided to land to be safe. I shut off the engine and flew around a bit - really not very different than flying with a regular harness - just noticing that there was extra weight at my feet.
Ooops - better remember to unzip before I get too close to the ground! There is definitely more to keep track of on this harness. On the right side leg "door" you have the tab to the line that pulls the zipper up. You also have the starter handle and the choke with it's jam cleat. On the left door you have the un-zip tab and the prop lock with it's jam cleat. On the left side of the harness near the waist is the angle-dangle adjustment and jam cleat. It took me awhile to sort through all the various controls to get things opened up again (definitely not something to be doing on final!) but other than that the landing was uneventful.
One strange thing I noticed on landing - it is pretty easy with my K4, but there is an extra part to it. You come in on final, wait until the legs start to drag, and then give it a mild flare. Because you are farther through the control bar with the motor weight you have much greater flare authority. Normally, once you flare and the glider stops the landing is "over". But what I noticed here was that the glider stopped, I landed on my feet - and then it felt like I was being nudged from behind and had to take a couple of steps to stay upright. The momentum of the extra mass behind you has to be taken into account.
The rain had started again, which was probably why I had felt the turbulence. I was about to start tearing down when it stopped again. So I went back and took two more quick flights to get the feel of take-offs with the new harness and my glider. These were quick flights - climb up to 2 or 3 hundred feet, do a loop of the field, and land again. The take-offs were easy and the flights uneventful. I found myself getting a bit sloppy on the third flight - just overload from all the new stuff - and decided to call it quits.
It's a cool toy, and I can't wait to play with it some more!
After the BooWah day Saturday at Big Walker (Randy's message) I was feeling pretty satisfied about having had a flying fix. But the forecast for Sunday morning was light SE, which was perfect for taking the Mosquito out to Clover Hollow. The main hill faces NE, but it almost always blows out of the SE on a sunny day, which is right up the valley. I suspect this is caused by convection up John's Creek Mountain which is off to the NW of the hill. And a SE day would ensure the wind would be straight up the valley. I have been wanting to see Clover Hollow from the air ever since I took my first hang gliding lesson there, 20 years ago. So Jean graciously agreed to accompany me so I could try out my toy on "home territory".
All my flights so far had been near Richmond, which is near sea level. The 'Hollow is closer to 2000 feet, so I was keen to find out how much the increased altitude would affect things. The day was sunny and a fairly steady breeze was blowing up the valley, generally 5 to 10, although some lulls and direction changes indicated the thermals were already forming.
I figured out some things about the harness since the last write-up, when I wrote that the beginning part of the run felt awkward until the glider was flying itself. I now realize what was different from my regular harness, which is the amount the glider rises during takeoff. I had not expected there to be any difference because my height above the control bar in the prone position is nearly the same. But the way the main support straps are attached to the harness have a pronounced effect. With my normal harness the straps come in at the hips. I can get the main strap nearly tight while holding the control bar with the 'grape vine' grip. Because most of the slack is already taken up the glider does not rise much and I can use that position all the way until I prone out. With the NRG, the main strap comes into a pulley system on a carbon plate located in the middle of my back. I am at the same height while prone, but hang much lower when upright. Thus the glider rises more during the run, and my hand position has to change to accomodate the glider rise. That was what felt awkward last time. I'm starting to think that, for this reason alone, the 'beer can' grip may be better for launching the NRG. I don't like it as much, but it means I don't have to change hand position during the launch run.
After doing an engine warmup I got lined up into the wind for a nice smooth cycle, bit down on the throttle, and started my run. There may have been some loss of power from the altitude, but with the higher wind velocity than previous flights it was not noticeable. I came off the ground quickly and easily and went into prone position. Then the glider started turning left. I started to correct, but then remembered my flight plan to do that anyway, so as to maximize the field available to me if I had a sudden loss of power. So I let it continue the turn for a bit then tried to stop it. It wouldn't respond. So I let off on the throttle a bit to reduce the thrust. Still turning. The left turn had taken me over a small hill, and I had lost a lot of ground clearance because of it. I decided it was time for emergency procedures and spit out the throttle and did a major correction, throwing everything I had into making a right turn. I finally got it to turn back to the right, but I was sort of slow and almost on the deck. The reacquantaince with earth was not at all pretty, but I didn't break anything. Well, damn. It shouldn't have been that hard! The only thing I could figure was that I should have been quicker to back off on the throttle. I did a walk around to check the glider, and then I saw it: a luff line on the right side had gotten snagged under a batten. That's one of those things I always look for during a pre-flight, and I would have sworn that I had checked that this time, but I obviously hadn't. Even so, I was greatly relieved to find the cause of the problem, and got a good lesson in not getting slack on pre-flights!
So I got back in take-off position again. This time I lifted off easily again, but no radical turns. A couple of times during the climb at full throttle I found the glider getting into a turn that was very difficult to get it to come out of. But every time I found that either reducing the throttle or pulling in on the bar would get things back in control. In fact, even though I knew I needed to have the bar well back, I came to the realization that when things got difficult in a turn like that that I had invariably let the bar out too much. As long as I kept it back by my waist control was fairly easy.
Thermals were definitely working. Once I got up 5-600 feet up I backed off on the throttle to save my not-yet broken in engine. My vario showed everything from sink to 1000 fpm up. I flew over Marty's house then came back and just enjoyed the new view of a place I had come to know so well. I flew over towards John's Creek mountain to check out the soaring potential, but I was starting to get rocked a bit by the thermals and wanted to get more used to power before I flew much in those conditions. I had climbed up to over 1200 feet at that point and zipped up my harness. I figured out how to do that without taking both hands off the control bar: pull the zipper up with one hand, then put the zipper line in the hand that was holding the basetube (to keep it from getting unzipped again) while I reached back with the free hand to clip the leg into place (and then switched hands to do the other leg).
Once I decided to land I left the power on until I had the harness unzipped again, then cut the engine and locked the prop to prevent it from rotating (a rotating propellor has higher drag). I had plenty of time to play around in the thermal bumps I found on the glide back to the field. I didn't find anything real developed, but I did find a nice patch of lift over the 'Tree Line Slope' (those of you who know the 'Hollow will know what I mean) and I found it easy to turn in and gained a bit. From that little bit of experience it seems like thermalling with the Mosquito is not much different than with a regular harness - about the main thing I noticed was it took more effort to swing my feet because of the extra weight down there.
It was a half-hour flight with a good landing. Together with the 2 hours at BW yesterday I had my flying fixes for the weekend! (and I'm still real happy with my new toy!) This photo is taken shortly after takeoff:
I was out at the Va Tech airport with Wayne several weeks ago. We planned to get out there pretty early, but somehow, by the time I was ready to go, it had already gotten pretty thermally. It didn't seem that strong, though, so I let my (over)confidence get the best of me. I ran directly into the wind, and the glider lifted easily. Remembering things I'd read about being sure to get plenty of speed before climbing, I pulled in the bar and just ground skimmed, building speed. Then I hit a thermal gust and got popped up, but still going reasonably straight. I went prone to get my legs back into the harness to stabilize the thrust direction, and at the same time the mouth throttle twisted in my mouth and I briefly lost power until I got it rearranged again. By this time I was in a turn, so I eased off the power (again) and got the wings level again (although I was now no longer directly into the wind). The ground was coming up rapidly, and I was in good shape to make a landing (which I should have done!!!) Instead, I had the brief thought that "I can save this!" and went to full throttle, probably 5 feet off the ground. I got into another turn with no room to correct, and came in slightly sideways on the wheels. The ground loop pushed the harness sideways and a leg broke, which allowed the prop to hit the ground, and it broke.
I got a new prop from Tennessee Propellor - they make nice wooden ones for about half the price of the carbon fibre one, and it isn't that much heavier.
The next week I went out to Clover Hollow to try again. The wind was very light (it was early evening), and I could not get off the ground in two attempts. The glider would start to fly, then settle, obviously not at full flying speed. I had taken off at Richmond in the same winds, so I concluded it was the difference in altitude (2000 ft).
I started doing some calculations and going over some comments people had made on the flphg list (foot launched powered hang gliding). Several people had said they didn't think the K4 was a very good glider for a beginning pilot, because of high stall speed, and stiff roll qualities. The glider manufacturers don't give very useful info on stall speed, most just say 25 or "less than 25" with max loading. Well, a professional athlete running 100 metres in 10 seconds is only averaging 22 mph! With running shoes, and without a glider. Obviously real stall speeds are lower. Some estimates I heard for the K4 stall speed are 20 mph. With the Mosquito, I am 5-10 lbs over the max weight of 235 lbs. Doing the air density calcs ( http://www.printwares.com/densalt2.html - this site calculates changes in stall speed relative to the Standard Atmosphere - 59F at Sea Level), my stall speed out at the hollow would be 16% higher, getting it up to 23 mph. With the additional weight of the Mosquito, my stall speed would be about 7-8% higher than I was used to without it. In a light wind launch on a hill, you can dive a bit to get those last couple of mph, but with the Mosquito on the flats you have to run every one of them (and hopefully more than just the minimum possible speed).
Faced with those numbers, I decided maybe the K4 was really not the glider for this. Besides, I've been flying it for 8 years, and I have been toying with the idea of a new glider anyway. Dennis had a great write-up on the Airwave Sportser in HG mag, the large size of which goes up to 265 lbs. But as I started asking questions, the dealers indicated that they were hard to get (8 weeks minimum) and that Airwave seemed more interested in making PG's than HG's, so even that number was not reliable. I also looked at Targets, WW Eagle, and a bunch of others. I finally settled on the Australian Airborne Sting XC2 175 ( http://www.airborne.com.au/pages/gliders.htm ). It is a novice/intermediate glider, with an upper weight limit of 298 lbs(!) and it was reported to be easy handling with a low stall speed. Matt Taber had just gotten in a shipment, and I picked mine up at the Yellow Freight terminal Thursday night.
The Wind Gods must have been in a good mood, because less than 24 hours later I was standing on the BW launch with it! The 175 is 20 sq larger than my K4. Now 20 sq ft on a 30 ft wide glider is only 8" along the trailing edge, but this thing looks huge! I have to actually stretch to reach the nose during setup, and on launch it looks like the nose is miles out in front of me. The wind was coming in nicely, maybe 10-12. I played with the nose angle, just flying it in place, getting the feel of it. The tell tales were changing direction a bit, so I could tell it wasn't entirely smooth air. The most surprising thing to me was the ease of roll. A wing would start to lift, and when I would pull down on that side, it would just come down as if it had power steering! Ricky was there to spot me if I needed it, but I never needed any help. Regardless of which wing tried to lift, just a tug would easily bring it right down!
Launch was very easy, although I had a sort of wobbly exit from the slot - the roll was so easy that I was over-correcting, going left then right, etc. The lift was good at first, then sort of died, and I was scratching at launch level for quite awhile. Even being pretty light on this glider (hook in about 200 for a 178-298 range) - scratching in the bumpy stuff down low was quite easy (although I stayed out aways just to be sure). Eventually I found a good thermal and then everything turned on again and I was never less than a 1000 over after that.
Pretty easy to fly! It has a VG, and even full VG didn't make the handling that much stiffer. Roll was very easy, although pitch pressure is something else! There are basically two speeds to fly, either near trim, or with your arms locked! Anywhere in between there is a *lot* of bar pressure (can you say "pitch stable"?) Thermalling was quite easy, with it neither wanting to roll into or out of a thermal. I did a few mild wangs, and everything was quite smooth and predictable. Arms locked for high speed it stayed straight with no tendency to wing walk. Although I'm sure the top speed is not all that great, I also didn't get the feeling that I was falling out of the sky at high speed.
I finally came down at under 2 hrs simply because I was cold! There was a fair amount of turbulence over the LZ, but control was easy, and I even set up a NE landing with no problem. There was a fair amount of breeze when I landed, so that was very easy - but not a good test of its landing capabilities.
For the kind of flying I do anymore this is a great glider. Float and Boat with minimal stress. And if I really want speed, I've still got the K4. The Sting appears to be well made, and has lots of new features like the spring loaded battens (no strings, they just latch into the trailing edge of the sail) and a pip-pin for the control bar. Only 7 battens per upper side makes set-up a lot easier. And an unexpected bonus - it has a removable keel section that makes it suitable for the Mosquito with no further mods (except for cutting the little bungy cord).
I'd like to get a little more launch/landing practice on it, then on the the Mosquito!
After a couple of flights on the new Airborne Sting I was itching to try it with the Mosquito. The Monday before the 4th was forecast to be NE, so Jean and I went out to Clover Hollow late in the day. I decided to take this stage in steps and get some airtime with this combination before trying to launch from the flat in calm wind. I made the extra effort to hike the glider and Mosquito (two trips!) to the top of the training hill. It was a very easy launch - I added power as I gained speed (instead of full throttle at once) and very quickly found myself in the air and climbing.
This glider makes a lot of difference! With my K4, if I got to more than a slight bank angle under full power I usually had to reduce the throttle to get level again. With the Sting I could roll into and out of turns at full power. The rolling out part took more effort than without power, but it was quite doable.
Shortly after I got into the air my vario battery died, so I have no idea about climb rate for most of the flight. My impression for the first part of it was that I am probably getting at least 200 fpm, although it is hard to say if it is much more. Because the engine only has 1-2 hrs on it I did not run it at full throttle for more than a few minutes at a time. Between times I would back it off to about a half throttle "cruise", where I was probably just maintaining or climbing slightly.
The evening air (I launched after 7) was quite smooth with clear skies, very little wind, and almost no noticeable thermal activity. Without the motor I would not have been up there. And it sure was pretty. I just tooled around the valley taking pictures. I started out with about a half tank of fuel and flew under power for about 50 minutes at varying states of throttle. Pretty neat to just be able to fly wherever you want without having to look for lift to get there! A full tank of fuel should get about 2 hours of powered flight if you are not climbing at full throttle the whole time.
With still a little fuel remaining I shut off the engine because the shadows in valley were getting pretty long. At that point I think I was at least 2000 above takeoff, and perhaps more. I got about a 10 minute sled ride back down to an easy landing.
I've now got about 3 hours on the Sting in thermal conditions and another hour with the Mosquito. It is a fun glider to fly and easy to setup and I'm quite happy with it. It also is a *lot* easier to fly with the Mosquito than the K4 was.
I have been rethinking light wind flat ground launch technique after doing some practice running with the glider in a field with no harness. I found that very slight differences in nose angle/running technique made the difference between the glider flying itself or just pulling along a drag chute. These small differences could easily get lost in the sound and fury of a full throttle run. I think when I try the flat ground next I will start out slowly, using just enough throttle at first to overcome the drag of the skids - and get to where the glider is just flying itself and lightly tugging at the straps. Only after this stable state has been achieved will I go to full throttle, and then smoothly over a second or two. Sounds good in theory - we'll see how it does in practice! It may take awhile to find out, unless Marty mows the field - the grass is getting high enough that it wouldn't be good to run the prop through it very far. But the top of the training hill should still be OK.
The forecast for Friday was light northerly winds. I have been toying with the idea of flying the Mosquito from Big Walker, but did not want to do it for the first time on a no-wind day. And there also would be no point if it was guaranteed soarable conditions. I also had questions about the height of the grass (possible prop damage/wear) and the height of the brush in front. I loaded both the Mosquito and my regular harness.
Med and Ricky had been at the launch since early morning - the grass was all cut and they had done some major work clearing brush in front. The wind was coming in nicely, probably 5-10. Ricky had a nice launch and gained some altitude initially, but eventually sunk out. Larry and Tim flew next - Tim got up but Larry sunk out. It was just marginally soarable, so I decided to wait a bit to make a decision. If it got better I would fly my regular harness, if it lightened I would go with the Mosquito. I went down to the LZ to pick up Rick and Larry to give the situation time to develop. In the meantime Med also flew and landed.
Back on top I finally decided to go with the Mosquito. The launch conditions looked perfect, including the freshly cut grass. Tim had gotten to maybe 1000 over for a little while, but more often he was just a few hundred over. Ricky and Dennis helped me get ready to go, mostly by just holding the nose while I got the Harness hooked to the glider and fuel line, etc. hooked up. It really didn't take much longer than with my normal harness.
I started the engine and got settled into launch position, which included carefully picking a running path so that no rocks would be sticking up between the skids to damage the prop. The wind was pretty steady, but light with a N-NE cross to it. I had backed up as far as I could to give myself plenty of running room. On a straighter cycle I started running and then increased the mouth throttle to full as I got closer to the lip. I guess it was a combination of the 5-8 wind, some possible lift in front of launch, and the full power - but I suddenly felt like I was the Space Shuttle blasting off! Ricky and Larry later said that it didn't seem like I was climbing that steeply, so I guess it just felt like it. Anyhow, it was a very easy launch and I could have done it with a lot less throttle.
Having my own thermal with me I didn't even bother turning but just flew straight out, climbing away from the mountain. After gaining about 7-800 ft I decided to go exploring and headed straight out to 42. One section must have had some serious sink, because even with full throttle I was showing about 50 fpm down. But most of the way I was climbing at maybe 1-200 fpm with about half throttle or less.
I came back to the mountain with about 1000 or so over and cut the engine off. Tim was down at several hundred over the trees over to the left of launch (towards High Rock), and I didn't find hardly any lift where I was. After losing several hundred feet I tried my first in-air restart. A couple of tugs and it started right up - cool!
I motored over to where Tim was and spent most of the rest of the flight in that area. I'd climb up to anywhere from 8-1300 over and then shut off the engine and work what lift I could find. It was pretty light at that point (after 6 pm) and just barely soarable. Tim and I were the only ones flying. During the light parts of the cycles we'd get down to tree top level, and Tim was even below the top of the mountain a number of times and still managed to get back up (excellent flying, Tim!) For myself, when I got down close to the ridge, I'd just give it a few tugs and climb back up out in front to give Tim plenty of room to scratch. I did about 5 restarts, and all except one took no more than a couple of tugs. The one difficult restart took maybe 10 tugs total, and I had to go through the cold start procedure (choke, etc) to get it to go. But even that took well under a minute and I was always able to have one hand on the control bar.
The other new part of this flight was thermalling with the Mosquito harness (power off). It does feel a little different, at least to start. At first it just seemed like the glider was much stiffer than with my regular harness, but then it seemed to get easier, so I presume that was just a matter of adjusting my technique. Overall it really didn't seem to affect things much. I don't know about any possible loss in performance, but from just the perspective of flying for fun I was able to crank and bank pretty much like normal. Once I had been doing it for awhile I hardly noticed any difference.
I tried to figure out climb rates, and it seems they may be better than I thought, although it was hard to separate out from the air movement. A number of times when I was climbing back up I saw climb rates of up to 500 fpm, which I presumed meant I was passing through some lift. But those times that I cut back to idle to try to work it there wouldn't be anything there, although it would often be just zero sink. Most other times I would typically see rates of 2-300 fpm. My guess now is that the Mosquito knocks maybe 500 fpm off your normal sink rate; so if your normal sink rate is 200 fpm, you might be able to climb at 250-300.
The sun was sinking lower, and I had gotten to try all the new things of flying the Mosquito at Big Walker except for one: landing. With the engine shut off and the prop locked in the horizontal position (to minimize chances of prop damage) I lowered the legs and unzipped the harness while still well above the field. The air was pretty smooth with just a little texture and a fair amount of sink over the LZ. I set up a normal landing on the hillside and it felt like one too. In fact it was even more like a normal landing than I expected, because usually with the Mosquito you wait for the feel of the skids dragging for the cue to flare, but with the steep hillside it was apparently time to flare before the skids touched. Once I landed I had to turn around and look to make sure it was all still back there, because I sure hadn't felt it! Checking the fuel, I found I had used less than half of it for over an hour of flying, probably 40 minutes of which the engine had been running.
So far, so good! This glider(Airborne Sting)/Mosquito combination is working very well, much better than with the K4.
Anyhow, last Sunday looked like it might be one of those rare days at the Hollow. The wind was kind of switchy at first (mid to late afternoon), but I set the glider up just to do some practice runs with it. Even with 175 squares and running with everything I've got, getting the glider to fly properly on flat ground in no/very little wind was not as simple as it sounds. The nose angle is very sensitive at those air speeds - with the nose just a couple of inches too low it will never fly; having it just a couple of inches too high and it is just acting like a drag chute. And if there was even the slightest bit of tailwind, forget it! I put on my old knee hanger harness so I could fly the glider against the straps while I was running, just like I would be with the Mosquito. Of course, with the Mosquito pushing you along during an actual launch, you don't have to work so hard - but I wanted to be able to feel like I had good control of the pitch. It seems like the thing that is easiest to do wrong (and probably the most expensive) in launching a powered harness is to let the nose angle get too high and try to fly before it is ready.
At one point the cycles were going up the hill, and I carried the glider up for a simple flight. I like flying the training hill, but the Hollow does not have a wind direction that works very often. Jean had our new DV cam along, and was filming my runs and the hill flight. A video is excellent feedback for seeing what you are actually doing versus what you *think* you are doing. I had a good launch and landing, and the winds were shifting to the catabatic direction (nearly opposite to what they had been, coming down off John's Creek Mt).
The catabatic winds meant two things: that the little bit of wind there was would be smooth and steady, and that it was getting very close to dark! I did a couple more practice runs and felt confident I could maintain good control of the pitch. It was getting deeper and deeper dusk as I hooked up the Mosquito.
But the launch went very well - instead of immediately going to full throttle I matched the throttle to speed, increasing both gradually. I concentrated on just maintaining the proper pitch angle and soon I lifted off very smoothly. I was very pleased - I had been visualizing this technique for weeks - so it was a very good feeling to get it to actually work. It was getting so dark that I only had time to do a two minute loop around the "pattern" and land again, but I was happy!
I posted a video of the takeoff in the files section:
For a text book example of a good takeoff in no wind check out:
http://www.powerplanes.com/USnowindRH.mpg
Notice the last couple of extra moon-walking steps he takes.
Yesterday was a cloudy and drizzly morning, but the winds were forecast to be light NE, a good direction for Clover Hollow. Although I had expected it to be drier, the forecast promised that it would be drier later in the day. And I had already arranged with a friend to go along, so I did not want to pass up a rare opportunity to fly during a weekday. Arriving at the Hollow the wind was light but steady, right up the valley. The ceiling wasn't very high, maybe 50 to 100 feet above the top of the training hill - but all I really wanted was a chance to practice repeated flat-ground takeoffs in smooth conditions.
Of course, by the time I was set up the wind had died to near nothing. I was definitely going to get some "light wind" takeoff practice! Most of the time the wind flags hung limp, and I had to depend on Pete blowing bubbles to have any idea of what the air was doing. Even though it was very light, I definitely only wanted to try this when whatever air movement there was was towards me!
I have always been against the "beer-can grip" for launching a hang glider - I just don't think it gives you nearly the control of the "gravevine" grip, especially in gusty conditions. But, I am coming to realize that maybe it is the better way to launch a powered harness in light winds. The difference being the distance you have to run (from the videos I have been counting well over 20 steps for a light wind takeoff) and the control you need to have over the nose angle. The beer can grip just seems to work better here.
My first launch went pretty well; I had a good run and got off the ground smoothly. I was a little disappointed though because I felt like I had stopped running a couple of steps sooner than I should have. Launching a mountain site you are usually just fine by the time you feel the glider lifting you, but here you really should be ready to take an extra step or two. I just did a big loop around the area and set up for a landing. At less than 100 ft over the top of the hill the ground was looking pretty white and vague, so there really wasn't much flying to be done anyway. My landing was also pretty good, although I had to run it out a bit to keep the nose up.
As soon as I landed I noticed the wind was actually blowing a little bit again, right up the valley, so I immediately carried the glider back to launch position without unhooking. I only waited just long enough to catch my breath, then got ready to go again, since this wind cycle would probably not last long. A longer rest would have been better. My takeoff started out OK, but at one point a wing dropped a little bit and once again I quit running too soon. It was still a successful launch, but I felt like it had been really sloppy. Once again I did a single pattern loop in the bottom of the clouds and landed. The landing, too, felt sloppy, although the nose didn't touch the ground. This time I unhooked to take a bit of a break and rest and relax before trying again.
For my third attempt the wind was nearly zero - the bubbles Pete was blowing just went a few feet and fell on the ground. After what seemed like a long wait the bubbles actually started drifting very slowly in my direction. While I was waiting I had been visualizing all the steps of the takeoff, determined to keep running this time! As it turned out, I think it was my best takeoff ever - the run felt smooth, the pitch felt good, and I kept running right into the air. I even have it on video, see:
In the first few frames of the video you can see the bubbles floating in the air in the upper left corner.
During the wait between flights the ceiling had lifted another 1-200 feet, so it was now 4-500 ft above the valley floor. I had already decided this was my last flight of the day, and with the higher ceiling I decided to go touring! It was really great - I flew up to the head end of the valley, just touching the ceiling of clouds! There were plenty of fields available so there was no worry about what to do if the engine quit. I felt like I was in my own little aerial playpen - ringed by ridges and topped by cloud. Here and there the ceiling would be lower and I would have to reduce the throttle and pull in a bit to maintain ground reference. There were also tendrils of clouds hanging down, and it was fun flying around and through them.
To an old hang glider pilot, the freedom to fly wherever I wanted in the valley, even on a day that wouldn't have been possible for a mountain launch, was really appealing! I flew down to the landowner's house and did about 3 or 4 360's over it. The entire flight was at around 400 feet AGL, and it was really neat to be able to relax and sight see at that altitude!
Finally, seeing about all there was to see in the valley, I went back to the LZ and landed, which was also my best landing of the day. By the time we got back to town the ceiling had lowered and it was drizzling again. I felt pretty confident that I was the only hang glider pilot around who had gotten any airtime this day!
Yesterday was a beautiful day out at Clover Hollow. The wind was generally 5 mph, give or take about 5 (depending on the cycle) and varied between straight into the training hill and straight up the valley (Mosquito take-off direction). I was doing a couple of flat-ground runs with my old knee-hanger harness (practice for Mosquito take-offs) when I saw something I haven't seen in years: another vehicle with a glider on top coming down the field. It was John Graham and family, and he was coming out to get some launch practice on his Fusion.
There was a little more wind than I was used to for the runs in the knee-hanger and several times I got real light on my feet while running. And one time I actually got off the ground and flew for a couple of feet and still had enough energy to get a mild flare out of it. First time I've ever done that.
I went up the hill while John was still setting up. Because the wind was coming in pretty nicely I went to the top to see if I could get an extended ride out of it. But I didn't get any lift - at least in close to the hill, and then I had the problem of having to make turns to get down without running out of field. That's when it started getting a little squirrelly. I was getting popped (up and down) and wing rocked more than I expected. A final turn too close to the ground and then a zero-step landing.
Then John and I went back up the hill together (only half-way this time) - but the wind seemed like it was settled in to flowing straight up the valley (cross to the hill). After waiting a bit we headed further up the hill and make the long walk over to the "tree line slope", which almost always is launchable in those conditions (and is about 260 ft vertical so it is a nice ride). John flew first and got a beautiful landing. I took off soon after in better conditions than John had had and made a number of turns before landing.
I decided to let things smooth out a bit before I tried the Mosquito. John had to pack up and leave to be somewhere else. I set the Mosquito up on the glider and sat back to watch things for awhile. It seemed to be much lighter in the field so I got ready to go. I had an easy take-off at 4:55 and seemed to have a really good climb rate. I got bounced a little bit for the first 500 feet or so and then it seemed like whatever bumps I ran into were just thermals.
I had the goal of seeing Mountain Lake from the air - something I had never done from a hang glider before. The climb was pretty steady, and by the time I was about 2000 over I went back over the spine of John's Creek Mt and got some lift to add to the Mosquito's power. I was 3500 over 15 minutes after take-off. Then I cut back the throttle a bit and started enjoying the view of Mt Lake, which was plainly visible. I fumbled around getting the camera out of it's pouch and took a bunch of pictures. At some point I looked down and was startled to find out how far I had drifted towards the lake - I had been just barely behind JC Mt, and now I was past the next ridge and JC was at about a 2 or 3 to 1 glide. That was when I first realized there must be a lot of wind up high. I was maybe 4000 or 4500 over the field at that point but it seemed like it was pretty far away given the wind. I decided it was time to pay full time and attention to getting back in that direction!
Now, there were fields that I could have reached if I had lost power, but they would have been a long ways from where Jean and the van were, and I really didn't want to do that if I could help it. With the throttle about 80 or 90%, and the bar pulled back to straight-arm position I very *slowly* penetrated upwind. At that bar position and throttle setting I was basically just maintaining altitude - although I think I did climb a couple of hundred feet in the 10 or so slow-motion minutes it took me to get back out over the Clover Hollow valley.
Once over the valley I let the bar out and continued to climb. The rest of my flight was just getting most of the way across the valley so that I could get a look at Pandapas pond and take some pictures of it. When I shut the engine off I was at almost 7700 feet, about 5700 over the field I had taken off from. I expected a nice long sled ride from that height, but it seemed like everywhere I went the air was sinking - I was coming down at 6-800 ft/min. Just as well, the sun was getting pretty low. And the air was glass smooth.
When I was down about 2000 over the LZ I started running into some turbulence. I was surprised to find it that high, but wasn't concerned - yet. About 1000 over it definitely started getting my attention. I looked out to see I was about the same level as Spruce Run Mt - and although it was maybe 3 miles away it seemed to be upwind of me based on what I could tell of the wind direction at that point.
The last 7 or 800 ft to the ground were not spent reflecting on the joys of flight - I wanted down! I've certainly been in worse, but finding yourself tilted into 45 degree banks when you are trying to fly straight tends to remove any complacency that might have been there! The last 100 feet or so were in the shadow of the training hill and things got better then. The wind in the LZ was between 90 and 180 degrees off of what it had been up higher - apparently just sitting in a big rotor! The landing was good and I was glad to be down!
I checked the weather after we got home and saw that they were forecasting stronger conditions as the evening went on, ahead of the weather that was coming in. I learned a lot about the winds in that place because of that flight. It has always been a mystery why the wind could be so variable in that field, and why the direction often didn't bear any correlation to what was elsewhere. And in this case I hadn't spent enough time looking ahead - I had just assumed it would be much calmer in the evening. Still, 90% of it was a great flight, and I had climbed over a mile on slightly over a half tank of fuel.
For some photos from this flight check out the Photo Gallery
Boo Waa!