Taking off with the Mosquito NRG
Your aim is to run very fast while you are buckled in equipment that weighs 60 or 70 kg (motor + wing). In other words you are doing something that sounds impossible. But it is quite easy actually.
The best way to do it is also the easiest: let the machines do the hard work
In more detail: Your objective is to run very fast without any muscle effort. You let the wing take a large percentage of your weight early on during the running and you let the engine push you foward. The only thing you will need to do is move your legs and keep the wing in balance (both in pitch and roll). At some point you will be running so fast that the wing will lift you by itself.
Here is the procedure step-by-step:
- You throttle up the engine until it starts pushing you and you start running and pulling the wing with the hangstrap (not carrying the wing foward with your arms). That means that you start running with the engine at around 50% of power and letting the wing rise up and start flying. Remember that you are pulling the wing with the hangstrap and once it is flying you relax your palms and your fingers because you do not have to carry its weight anymore.
- Once the wing has taken its own weight and is flying, you change grip on the uprights and you make sure you are relaxed in the arms, hands and fingers and not holdning tight. As long as you have a light hold on the uprights then you give the wing the opportunity to rise and tension the hang strap while your hands remain at the correct angle (a bit below chest height). As soon as you establish a balanced flying wing you are ready to increase your running speed.
- You continue accelerating and let the wing take its own weight and even a part of your own weight (let us say around 50% of your weight). As soon as the wing starts carrying some of your own weight, you start feeling much lighter and are able to do the "moonwalk". When you do the moonwalk, you feel like you weigh 30-40kg and it feels like you are about to lift. But in reality you will be able to retain that feeling of being light and continue running & accelarating without lifting off the ground. Remember that you still have to hold lightly to the uprights, at this point it is even more important to be able to "feel" with your hands what is going on. Your weight has to be lifted by your leg straps, not by you hanging from the uprights like a gorilla.
The more you accelerate, the more you will have to lower the nose of your wing in order to keep yourself from lifting off the ground. If you maintain a balance with the angle of attack while you accelerate (you gradually lower the pitch so that the wing is constantly carrying around 50-60% of your weight throughout the acceleration) then you will be able to run very fast without actually puting any muscle effort into it. You will, in other words, start moonwalking from early on and will continue moonwalking until the wing lifts you at a high speed.
If you lower the pitch too much then you will feel that you are heavy and each step will feel like a heavy thumb on the ground. You may even get a feeling that the wing is starting to fly faster than you can run and you are unable to keep up with it - in that case you allow the nose to rise a bit and return to the moonwalking.
The running is always done with a straight back and the hands on the uprights - not the speedbar. The running will thus be with a straight spine, the chin up and the push of the engine to the hips and a bit above. Not leaning foward and through the uprights like a free-flight launch from a mountain.
Once you are in the air, you have to change from uprights to speedbar, get your feet in the harness and pull the nose down so that you are climbing with speed 10-20 km/h faster than your glider's trim speed.
The change from uprights to speedbar should be done only when you are 100% certain that the running is over, the wing is climbing and there is no possibility to run any faster. As soon as you are prone and holdning the speedbar you need to pull in and accelerate for 3-4 seconds (you may find yourself flying parallel to the ground during that phase) and then slowly release pressure so that you establish a climb with good speed margins. The best climb rate is normally achieved with a bit of speeding, maybe 10-25 km/h faster than your wing's trim speed.
CAUTION: The technique shown on the video (excessive speeding after take off followed by quick release of the speedbar) is not recommended for pilots new to the Mosquito and should definately not be attempted by beginners.
What can go wrong?
The technique itself is easy and guarantees good take offs. But a lot of guys make the mistake of trying to launch with a motor harness by doing it the way they would normally perform a free-flight take off from a mountain.
But taking off from a flat field under power is totally different from a hill launch. If you apply the same mountain launch technique on flat ground you will end up pushing out the nose far too early. Unfortunatelly this happens quite often. In other words it is the instinct/habit that takes over and makes people stall the glider during take off.
If you have taken off from a mountain many times then you have built an instinct/habit/muscle memory and become accustomed to running a relatively short distance, reaching your maximum speed within a second or two (with the help of muscle power & gravity) and then letting the nose come up and lifting you while the mountain drops away. Even take offs with ground towing go fast and usually require just a few meters of running.
When you start from flat ground (with engine power) you will have to run a much longer distance and come up to a much higher ground speed while the acceleration will take a much longer time, maybe 10 or 15 seconds. These extra seconds will feel like eternity.
These differences often cause mountain flyers to think that "this running should be enough" or "I'm already running too fast" or "time to raise the nose" during the take off run and make a marginal take off or even stall the wing. You simply have to IGNORE SUCH THOUGHTS and JUST RUN for as long as it takes.
You should not be afraid to run a long distance. Run 100 or 200 or even 300 metres if needed, no problem with that. Just run and accelerate and resist the urge to "push the nose up" or allow the nose angle to increase too much. The wing will lift you when it is time to lift you - while you are moonwalking at a high speed. If you are not happy with something, just spit the mouth gas and abort the take off by making a flair on the ground. You can abort the take off whenever you want, which is not something that you can do when you launch from a mountain.
You have to keep away all the "mountain launch" thoughts that will go through your head once your running speed becomes high and continues rising. Just remember that the faster you run, the more normal and safe your take off will be. And it is TOTALLY OK if it takes you 5 or 10 or 15 seconds of running before you lift off the ground and start flying. Needless to say that such a long run will require a LONG field with no obstructions.
Any possible mistake where the pilot stalls the wing during take off can thus be attributed either to the power-of-habit or to bad choice of take off field.
Additional information about the above video:
Power Unit: Mosquito NRG with internal fuel tank
Hangglider: Wills Wing T2 with max hook-in weight 107 kg
VG setting: No VG at all during take-off
Weather: Steady wind around 5 km/h
Weight: Hook-in weight 105 kg (pilot + Mosquito + full fuel)
Other reading material:
Taking off with the Mosquito NRG