Gideon Yampolsky

February 2021 Humm … Nobody was ready to take me up ! There are 3 skydiving clubs in Israel. I spoke with all their managers (one of them is my good friend), but it did not work. Israeli airspace is highly congested and heavily regulated. Launching something experimental from the plane requires permits which seemingly impossible to obtain. Clubs did not want to risk their license. I then tried discuss it with hot balloon operators. Same result. I considered rising up by unmanned drone. Well, uncoordinated, in Israel, most probably it would end up by being hit by Patriot missile … Searching for solution was long zig-zagging path. Eventually, only one real option left – paraplane (powered parachute vehicle), with many modifications. So I needed to buy paraplane, learn to fly it, modify it for high altitude and wingsuit launching, find and train pilots who ready to take me up, find how to obtain permits for this. It took 8 months. Paraplane being built in workshop in Israel. Many special modifications were made in order to make it suitable for climbing to high altitude and safe launching of wingsuit jump. We equipped it with powerful Rotax 914 engine, not typical for such kind of vehicle. First version of launching pad. This initial version was modified many times until it has become sufficient for safe jump. Paraplane being tested by manufacturer - High altitude test flight More advanced version of launch pad being mounted on the vehicle

January 2021 I mounted engines on the boots. Added starter battery. Designed and assembled interface circuits, so it became complete system. On the ground system was running perfectly. So, I thought that system is ready for first powered flight. LOL It took another 2.5 years until that happened …

October 2020 Fuel container. I considered many options of container - on the back, or small containers on sides, etc. Finally I decided that container will be on the torso. I thought that it has to be flexible, to match torso movement. Container was implemented as fuel bladder surrounded by ribbed aluminum enclosure and nylon fabric. Fragments of the enclosure - I lined the enclosure with rubber, to protect the bladder. First I prepared small bladder, to test welding method - Actual bladder, 12 liters - Preparation of cover fabric - Almost final, first version - Design and build of the container was a lot of work. After container completion I tried to attach it by zippers to the wingsuit, but found that this attachment was not stable enough. I then prepared harness worn on the body and attached the container, through wingsuit, to the harness. And eventually I have to test it in flight … Note that chest strap of the skydiving rig just goes around it, but has no function in keeping it in place. The container is attached to body harness. I first jumped with container empty. On the next jump I filled it with water to imitate fuel weight. The first jump with the container was preceded by strong anxiety. I did not know what to expect from that big bump on the chest. But in air it behaved perfectly. It did not add any annoying feeling and did not create any difficulties to flight. Canopy deployment, opening and landing also felt quite normal. Good ! Currently (year 2023) I already have two containers, which both have similar dimensions, but different thickness. The capacity of thin container is 6 litters, and capacity of thick one is 12 liters, which supposed to be sufficient for 8 minutes of flight. This is newer design of 6L container –

For Jet Dragon Project I'm using Winx 210. Soft landings. Also, there is 8 mm rubber sole at the bottom of engine mountings.

September 2020 Next I needed control handle – to start and stop engines, and control their thrust. It has to be ergonomic and easily accessible while in flight. First I built several dummy prototypes from cardboard – And the final version – Later, in 2023, I had to completely redesign its concept …

August 2020 Engine mountings should be tested, but I did not want to use real engines for the test, as it could damage them. So I prepared dummy “engines” from plastic buckets filled with weights, for total 13 Kg. And I jumped with it – So far so good !

May 2020 I needed to check that it is possible to carry weight on the foot when flying wingsuit. Combined weight engines, boots, mounting brackets and starter batteries is 13 Kg . My concern was that it will pull legs down and I will stall. I checked it by series of wingsuit jumps while I'm gradually increasing weight attached to the foot. First I attached 4 Kg of weights (packs filled with iron pellets). Jumped, felt normal. Good. Then attached 8 Kg. With 8 Kg I stalled heavily - it was fall rather than flight. On the next attempt I de-arched in order to keep correct pitch and was able to fly wingsuit normally again. Good. Seems that it would be possible to fly with turbines attached to the feet. I had find how to attach the turbines . Key concern was about torsional stress they will apply – their thrust will tend to bend the ankle sideways. Some kind of support was required to avoid it. First “research” version of how to resolve it – I found that tracking shoes did not provide sufficient ankle support. Snowboard boots were better idea – Which leads to implementation looking like this – Engine mounting angle is 18 degrees. In wingsuit flight, legs are stretched apart, this will make thrust vector to be in match with flight direction.

LOL, you are right, it happened. Had to work hard to calm them. Now I'm more careful regarding running engines in neighborhood.

February 2020 I needed to confirm that turbines produce identical thrust. If they are, they both can be controlled by common throttle knob. On the other hand, if each turbine produces significantly different thrust, then their controls should be separated, which makes implementation more complicated. I built mechanical balance system to run two turbines simultaneously and measure thrust difference. Fortunately I found that the thrust of each turbine is almost the same.

I’m publishing the story of Jet Dragon Project – development of jet powered wingsuit system. It took 3.5 years, over 5000 work hours, and tens of aborted jump attempts, until first successful flight several weeks ago. During development I consulted many people, including dear fellow late Jarno Cordia, who had previous experience with jet powered wingsuit flight. However the new system was actually designed from scratch. January 2020 After initial assessment and reading publications on the web, I decided to use two P400-Pro jet turbines from JetCat. Each can product 400N thrust, so total will be 800N. According to calculations it is supposed to be more than enough for level flight, with approximately 25% extra power to allow climbing up. After receiving turbines several weeks later I assembled simple setup to see how it runs. First I checked that it responds to throttle commands - Then run it on the bench -

Thanks Jarno, very helpful !

Does anyone have experience with rodeo exit from Skyvan ? Skyvan has a back door, so jumping rodeo means passenger exits a little-bit before wingsuiter. I think we will roll over on the back and passenger will fall down. Are there any videos of rodeo exit from Skyvan ? Tips and comments are welcome.

It is not a balloon, but rather powered parachute (aka paraplane), with shelf mounted on the side for convenient exit. 400N * 2 jet engines attached to snowboard boots. I had technical issues which prevented engines to start in flight. These will be resolved soon.

I have only good things to say about Winx. I’m happy owner of one, and my next main will also be Winx. However, my friend experimented with deployment methods (shamefully have to admit that it was due to tips I gave him) and got heavy line twists. It ended in cutaway, twice. The fact that he has Winx did not help. Even Winx has its limits. I see Jet project mentioned. Here is my version :-)

Need advice: which full face helmet has a visor extending lower (toward chin) so it allows eyeballs to look down as much as possible. I’m currentyly using Cookie G3 and when looking down I see helmet’s chin mold, i.e. my vision in that direction is somewhat blocked. To make sense of what problem I’m trying to resolve, see the picture below. The display is mounted in the position as low as possible for Cookie. If I will try to mount it lower than that, part of it would not be in the field of view, obscured by helmet’s black plastic. So I’m looking for helmet with visor extending down, which will allow to mount display in lower position. Looking at different helmets I got impression that Bonhead Aero has better vertical field of view. Does somebody has experience with Bonhead or with other helmets and can advise on that matter ?

About what was inconvenient with Vufine display: It is supposed to be located very close to eyeball and has lens designed accordingly. But you would not want to put it so close to the eye in wingsuit flight, as it may hit the eye badly. Attempt to position Vufine at reasonable distance creates "tunnel vision" effect - even a slight shift of eye from the optimal position makes the image to disappear. No practical use by any means. As I posed the image earlier, assembling of AON2 on helmet front works much better. I already made about 200 jumps with this setup and believe it is a practical solution in terms of where and how display should be positioned. The AON2 can be replaced by any kind of custom implementation, but optimal position is as I mentioned. I'm currently designing my own custom solution with 5" 800 x 480 high-brightness LCD .

I was not happy with the result, and abandoned it after several test flights. Vufine display is not convenient to look at during the flight. Instead, I mounted AON2 on helmet front. This configuration works pretty good.

No

15 liters fuel bladder. Will be on the lower back, right behind BOC.

I need to make openings for engine mounts. You can see some details here – https://www.facebook.com/photo?fbid=2906758286118203&set=a.678091862318201 https://www.facebook.com/photo?fbid=2697855983675102&set=pcb.2697856870341680 https://www.facebook.com/photo?fbid=3098818256912204&set=pcb.3098833303577366 I will ask advice from our riggers, but cannot ask them to do the job. They don’t have materials and experience to modify wingsuits.

I need to do several significant modifications on ATC wingsuit. Since it is going to be continuous research process, I decided to obtain all necessary materials and skills to do it myself. Thereby several questions: Main surface material (like 210D Ripstop) – what are my options and where to buy ? What thread (size, type) should I use, where to buy ? Needles for sewing machine – type, size ? Are ball-point needles preferable ? Sewing machine – for start I intend to use household Bernina machine. Does it makes sense ? If not, what do you recommend ?

Well, I already ordered C4 suit. And I think jumping from ATC to RACE is too much. I will use C4 for a year or two before considering further upgrade.

Wow, you made it very clear. Thank you for comprehensive explanation. I will go for C4.