Thursday, August 05, 2004

Flying in the Brazilian Cerrado

WASP Power Unit
Moyes Sonic 190 Hang-Glider

A FLPHG is a normal hang-glider coupled to a power unit which gives it enough thrust so as to leave the ground and climb with a medium-weight individual, thus allowing that flat-landers profit from hang-gliders without having to rely on towing systems. As the majority of the world is flat and many flat sites offer excellent flying conditions it makes good sense to use such a machine to explore the free-flying possibilities.

In order to fly a FLPHG one must learn traditional hang-gliding first. Upon achieving a short level of experience (hang 2 rating or equivalent) switching to a FLPHG is not difficult at all, provided that some details are not overlooked.

April 2004 - The First Flights

Me and Phil Bradshaw arrived in Brasilia (the capital) on Monday morning, April 19th, 2004. We bought some 20 liters higher grade fuel to take with us because we were afraid that the normal brazilian gasoline which contains some 30% alcohol in it could spoil the WASP engine. We settled for a Shell V-Power gasoline that was the most expensive and supposedly unledded. We arrived at the farm late on Monday the 19th.

Tuesday morning we started setting up the whole circus! Everything was falling into place nicely, we cut the hangglider´s keel off and managed to produce a plastic PVC sleeve which was good enough to rest the glider upon, when the unit is not running.

Phil got me hanging on the unit inside the shed and I did a few simulations of zipping and unzipping and found out that only the leg clipping demanded a little more attention because of me not reaching the leg easily. This picture shows me on the left and Phil attaching the fuel tank to test the engine indoors.

After many months envying the birds of prey circling around in the abundant lift I would finally have a chance to get even !!

A typical soaring sky in the region:

On trying it out still hanging inside the shed, the thing that bothered was that the zipper wouldn´t stick when all the way up: it always slided back a little bit and so did the legs. If the zipper would stay in place then I guess I could reach the legs with my hands. But otherwise it didn´t seem all that hard to look for the cables and eventually reaching the legs. It turns out that the zipper really doesn't stay in place, i.e., it tends to slide back as you try to fully close. (Eventually I learned that the proper technique consisted of pulling the zipper partially, holding the zipper pulley with my teeth while reaching for the legs with my hands. Once the legs were locked into place no longer would the zipper slide backwards. The real catch is doing all that WITHOUT losing concentration on flying the wing!! As you look back for the zipper and for the first leg it is quite possible to get into an unwanted turn. Of course this will be more critical on a higher-performance wing like a rigid where I guess this could evolve into a spin risk situation. Practice takes care of this hurdle and reaching for the zipper and legs becomes a non-event.)

It is worth mentioning that we would be taking off from 2990 feet altitude, which would drain some power out of the engine, while at the same time making the air less dense for my wing. As we would later find out, this was no problem, as long as we had a little wind or a lot of space.

We finally took the unit outside, clipped it to the wing. It was the end of the afternoon and the air was smooth. Phil had it running for a while and finally said ok and took off in beautiful long strides. All of a sudden he was out of there! He climbed doing turns above the launch and after about 5 minutes came back for a nice landing!

We were so glad to be able to go to sleep with a success!! But I was getting so anxious during the whole ordeal! Afterwards we just had to pop a couple beers to celebrate !!

We woke up early today, Wednesday for trying a flight before the thermalls set in. BTW the weather had been perfect for the last 2 days, smooth in the morning with nil wind, very thermall during the afternoon and, according to Phil, glassy smooth in late evening.

There was a slight wind this morning as we took the WASP to the field at 7:30am. The battery had charged overnight and the engine kicked in nicely upon Phil´s third try. Soon he was taking off again for a short 5 minute flight. He came back and landed and reported that the thermalls were starting to kick in and that maybe we could wait for the afternoon for my first attempt. But I was on a GO mindset, and I knew anxiety could creep in as we waited during the day so I said I wanted to give it a go. We spent some time adjusting hang-loop height. It seems that Phils hangloop set was too short for me so that when I would pick the glider up it seemed like the unit was pulling me backwards making the whole position very uncomfortable. We tried a longer setting and Phil said I was too close to the base bar, the parachute was just scraping the bar. We finally set an intermediate position and this seemed a nice one.

So I picked the unit up, turned the engine on, had a full throttle 3 second warm up. Took a deep breath, bited the throttle and then I only have a few flashes of what went on: it was just like a normal ramp launch, in as few as 5 long strides I was walking on air. The angle of attack might semm excessive in this pic but there was a considerable amount of wind which gave me quite a strong lift, right after take-off I eased my position into a lower angle of attack.

The adrenaline was running high and I was biting the throttle like a dog clings to a bone!!! I was just trying to find the good bar position and letting the glider pick up some speed.

I started lifting then I gradually eased into position and I was flying and being rewarded with a very nice view of the surrounding areas.

The flight was very stable and I was climbing at 1,5 to 2 m/s according to the vario. Then I hit some early thermalling action and was a little worried as the wing changed direction by itself. I tried to compensate but wasn´t feeling full control maybe because of the limiting lines. Then I decided to ease the power a little bit and it helped but the main thing was to be firm in control. The wing would obey if I really commanded it. The foot throttle was a pleasure, real nice set up and soon I had spit-out the mouth-throtlle and stuck it behind the chute. I played around with different power settings trying to go for level flight and I was very happy to find out that level flight is very much noise-free. In fact even full throtlle isn´t very noisy while flying.

I tried to reach for the zipper and legs but I was having a little difficulty keeping the zipper up while reaching for the legs. The air was somewhat bumpy and I just thought that clipping the legs only to unclip them in a few minutes would be too much to handle in the 1st flight so I just let the legs there as I flew around for another 10 minutes. I was really enjoying it and this was the best part, I was so afraid I wasn´t going to enjoy it!

Then I started planning my approach. As I flew to the corner of the field I was checking all my reaches and everything seemed to be fine: choke, starting button on the left, engine killing switch on the right.

I killed the engine some 600 feet above the ground and went for a normal hang-gliding approach, had no trouble flying with the engine off I just noticed that I should pay attention to the wind on my ears more than to the bar position because of course my usual approach bar position would be too slow for my added weight.

No problem there either I just pulled in for extra speed and also noticed that I was losing height faster than usual which was to be expected, of course, but should be taken into account since we had to clear the pines on the approach. As I unclipped the first harness leg the zipper opened up automatically, that is, just the wind pressure on the dropped leg was enought to drag it backwards and cause the harness zipper to open easily.