Skyflash, Jet Powered Glider

[team_skyflash]

Hi everybody,

this is Fritz from germany. Our team is currently building the first prototype of a jet powered, manned microplane. We call it "Skyflash". You can find daily updates, pictures and more at our website and on facebook:
http://www.skyflash.org/Slideshow/Home-English/home-english.html
http://www.facebook.com/pages/Skyflash-Int/502971813056201
We started our project five years ago. Through some prototypes and models we came to the first real Skyflash airplane that is currently under construction. Our goal is total freedom of flight without large structures or anything around you. It should feel just like the wings are a part of your body. But, unlike a lot of skydivers, wingsuits or stuff like that, we will have a landing gear, a regular powerplant and easy, self-stable, controlability.
The plane will be powered by two 80hp jet turbines consuming 440gr/min of Diesel fuel. Wingspan is 3,40m and max. speed is planned at 200mph. Weight is typically around 250lbs including the pilot and everything else. The whole plane is controlled only by the movements of the pilot, just like a hangglider.

Our first roll and stability tests have been captured and uploaded to youtube =)

http://www.youtube.com/watch?v=EQpDz-0UPCw

I´d be glad to post our status and more information here if you like our project!
We hope to manage our first flight in the first or second quarter 2013. I´ll be very happy to see our post between all those great projects that I´ve already seen there!
In germany, or europe generally, we have no institution like the EAA and so I´m very glad that there are so many impassioned aviators here in the US.

Best regards from germany


Fritz

[rwanttaja]

Interesting project. The thrust line seems above the center of mass; wonder if you'll have to tilt the engine a bit to compensate for the pitch-down moment of power application.

With no aerodynamic controls and the pilot strapped to the structure, how is roll controlled? I understand you're using arm drag for yaw and leg motion for pitch. If a wing drops, how does the pilot pick it up?

What is your intended flight test plan? Are you going to glide test it first?

For some reason or another, this reminded me of a long-expired US Patent from back in the '20s:


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Ron Wanttaja

[team_skyflash]

Thanks first for posting this interesting patent! You´re definitly right - looks quite a bit like our design. But I think our dream isn´t the newest at all - We´re just crazy enough to realize it...

Regarding your points -
The nose down moment of the engines is not too strong but calculated. It will have to be compensated by the pilot at lower speeds and depends very much on the flown speed, the wing will create a nose-up moment at higher speeds. The nose down shall also be some kind of a stall protection - Whenever something gets critical you can put the throttle up and the plane will recover. Due to your feet beeing in the engines jet-stream, you can apply a lot of force (for example at take-off) to annihilate this moment even without floating air around you.
Also, in addition to what you see at most CAD printings, the pilot has a V-tail mounted at his feet. This has quite a strong lever-arm to the force applied by the engines moment.

The pilots reaction on a dropping wing will be pretty much like the reaction of a hang glider pilot would be - bringing your center of gravity to opposite direction. If that doesn´t has enough effect, he can, different to a hang-glider, also put his arm in front of the leading edge of the upper wing - thus destroying the lift there, and move his legs creating a rudder effect with his V-tail. We already tried that out with the preliminary gliders :-)

Tests will start directly with the engines mounted due to the very important influence they have on stability and applied forces on the airframe. We will post a lot of details regarding the tests and controls later on our website.

I hope my english is understandable, don´t mind to ask!

Best regards

[rwanttaja]

Thanks first for posting this interesting patent! You´re definitly right - looks quite a bit like our design. But I think our dream isn´t the newest at all - We´re just crazy enough to realize it...

Regarding your points -
The nose down moment of the engines is not too strong but calculated. It will have to be compensated by the pilot at lower speeds and depends very much on the flown speed, the wing will create a nose-up moment at higher speeds. The nose down shall also be some kind of a stall protection - Whenever something gets critical you can put the throttle up and the plane will recover. Due to your feet beeing in the engines jet-stream, you can apply a lot of force (for example at take-off) to annihilate this moment even without floating air around you.
Also, in addition to what you see at most CAD printings, the pilot has a V-tail mounted at his feet. This has quite a strong lever-arm to the force applied by the engines moment.

The pilots reaction on a dropping wing will be pretty much like the reaction of a hang glider pilot would be - bringing your center of gravity to opposite direction. If that doesn´t has enough effect, he can, different to a hang-glider, also put his arm in front of the leading edge of the upper wing - thus destroying the lift there, and move his legs creating a rudder effect with his V-tail. We already tried that out with the preliminary gliders :-)

Tests will start directly with the engines mounted due to the very important influence they have on stability and applied forces on the airframe. We will post a lot of details regarding the tests and controls later on our website.

I hope my english is understandable, don´t mind to ask!
Your English is excellent, especially considering that you're discussing technical details.

You've looked into the nose-down moment with power, so I'm feeling better in that regard.

I'm still just a touch uncertain regarding roll control. CG shift is a classic method of control (invented by a countryman of yours over 100 years ago, I believe :-). But the CAD drawing on your web page makes it look like the pilot was going to be strapped solidly to the wing...if he is, how does he shift his weight? Or is he hanging from a short harness that lets him shift? I can see disrupting the airflow to control roll, but is the pilot going to be able to make the necessary arm motions at 200 MPH?

I can see you needing the engines in place during testing. It just seems to me that a glide test with the engines off might allow the pilot to get accustomed to the handling prior to being under power, and without fuel and hot metal being present. Though I expect power-off and power-on pitch handling to be quite a bit different....

Ron Wanttaja

[team_skyflash]

Thanks you! If I may choose a totally wrong vocabulary just let me know an I´ll explain further what I want to say =)

I understand what point you´re making regarding the roll control. The difference to other aircraft is that we don´t need a very wide CG-shift due to our reduced wing-area and our aspect ratio of just 3,4.
We have an physiological advisor in our team who very much influenced the development of the pilots mounting. Totally fixed without any chance to move is just the hip of the pilot. This means that, for no reason ever, even in gusty conditions, the pilots whole Body will move anywhere - for safety reasons. The hip, which represents the CG of the human body, is his fixed point. Whenever the pilot want´s to stabilize he can strain all his muscles - thus bringing the plane back in neutral position. He is always in control of the airframe. Unlike, for example, the pilot of a hang-glider who has no direct physical control of the wing.
When our pilot wants to move the plane he can swing his arms, his chest and, very important, his legs to the side he wants the CG to move to. Supported by the aerodynamic effect of this body movements, the plane will react very fast.

So what am I trying to say; Basically our plane uses very much a combined form of CG-shift and aerodynamic controls. At low speeds, when the aerodynamic forces are lower, you mostly control the plane by moving your CG. This gives you a very good control and feeling of what´s happening, especially when taking off or landing. At higher speeds you switch to a mostly aerodynamical control and align your body to the airframe.
The forces applied by the pilots movements have been tested with the 2/3 model when plane and pilot were hanging on a string in 1m height.

Regarding your question to the force needed to move your body at 200mph. We in germany have the advantages of our Autobahn ;-) We just tried the attacking forces up to 160/170mph out...
Your ability to move is of course very much affected by the immense airspeed, but you can still make the movements needed to control the airplane. At those higher speeds you also need a lot less body-motion to create the force you need to turn the airplane.
Its important to know that 200mph is representing the upper limit of speeds to be flown. Typical flight speeds will be around 70 - 120mph.

I hope this could answer some of your questions =)

[rwanttaja]

Excellent, thanks! Looking forward to watching your progress.

Ron Wanttaja

[team_skyflash]

All components of the Skyflash have been put together for the very first time =)
There´s still a lot of work to do on the left wing to get it finished, but we´re on our way.

You can see a bunch of new pictures on facebook: http://www.facebook.com/media/set/?set=a.503294929690556.109801.502971813056201&type=3
The dimensions of the airplane become visible for the first time in reality. So far the parts

We work hard and plan to get the covered plane ready to "roll out" by the end of this year!

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[team_skyflash]

Hi everybody,

I explained some technical questions here:
http://www.homebuiltairplanes.com/forums/aircraft-design-aerodynamics-new-technology/14513-skyflash-jet-powered-human.html#post159472
Especially interesting for those who wonder about stability and airfoils =)

Best regards

[team_skyflash]

The first wing is covered =)
Looks great to me. Incredible stability and very good surface quality.
More pictures on facebook!

[team_skyflash]

We will have to wait for some parts now so we won´t get everything done in 2012. Actually we´re waiting for some covering materials and so we will now end our work for this year and celebrate the new one!

Happy new year to everybody! Stay healthy and good luck for 2013! http://www.homebuiltairplanes.com/forums/images/smilies/smile%20happy.gif

[team_skyflash]

We finally reached our first major goal: The pilot and the plane are connected for the first time!
The pilot is capable of walking, running, standing (for hours) and has a great feeling of the airframe and controlability. He says: "I feel like I have finally spread the wings I always wanted to have" :-)
We will now build in the first engine again to continue with rolling tests of the gamma-phase. This includes several speeds including the lift-off speed without mounted V-Tail so that the plane won´t climb. Slight hovering above the ground is the target of this phase.

Our website has also been updated with new pictures and more. Visit us there =)


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[team_skyflash]

We finally reached the status were we could perform the very first taxi-runs. During calm weather and low winds we were able to reach 31mph without any problems. Controlability and stability is better than we could hope and I really had to work a bit to prevent the plane from hovering. The drive had been reworked a bit and should be able to work on gras-runways and up to 100mph without problems.
Weight is finally measured before the runs at 119kg or about 260lb including about one gallon of diesel and everything needed to fly. Because we still have only one engine installed (second one is finally in delivery by now) the plane has a steering to the right which I had to cope with (You can see that with increasing speed in the helmet-camera view). But that wasn´t really a problem.

My first impression is that we have a very managable and stable concept until yet. We can assume that, given a tendency to hover up without pilots interaction at 31mph with low AOA, the predicted V1 speed of 35mph will be realistic. Our predicted weight of 286lb will also be no problem even with more fuel and a second engine inside the plane :-)

Here you can find our videos from those latest tests:


https://www.youtube.com/watch?v=E3-KMAyyE64


https://www.youtube.com/watch?v=DpvhO2BdRyA

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Best regards from germany!

[team_skyflash]

Listed as Top 15 Innovation at Trendhunter =)
That motivates!

http://www.trendhunter.com/trends/skyflash-jet-powered-human

[Frank Giger]

Gotta be a Swabian crew building this!

;)

I'm completely impressed at the audacity and level of engineering involved.

[team_skyflash]

Well in fact its more a lower-saxony crew =)
Thanks!

[team_skyflash]

Today we reached the next milestone. The high-speed taxi tests were carried out and showed only minor problems. The Skyflashs hovering speed could be determined at about 32mph.
When the plane starts hovering the pilot has to work keeping the plane going straight because of the asymmetric thrust forces. You can see that when the plane passes the camera with one wing higher than the other.
Also we noticed that the pilot needs his elevator to be able to lift the planes nose and start climbing - just as planned. The controlability is as good as it has been on the last runs. The pilot slowly becomes more familiar with the handling.
Next steps will be the mounting of the second engine to see if any problems occur.

Our latest video showing some rough CG-Check and scenes from the test including the lifted wing:


https://www.youtube.com/watch?v=6k9-UCQULqE

We plan to bring a test-report on our homepage tomorrow explaining some of the results =)

Best regards!

[team_skyflash]

We just managed to get our first report online =)
We have established a new sub-site in the "Tech" section of our website. The first report has about one page of text and we will bring up new ones with every step we make.
I hope that this will answer some questions that are commonly asked.
If you have any questions or comments to it please just let me know. It´s a new section an we want to make the best of it:

http://skyflash.org/Slideshow/Home-English/Test-Reports/test-reports.html

[team_skyflash]

This week discovery channels "Daily Planet" broadcasted a pretty entertaining TV report on our project. Although it is of course also entertaining it contains some nice pictures and facts on the project.
Would be great to hear how you like it =)


http://www.youtube.com/watch?v=yELa2LvRFgs&feature=youtu.be

[team_skyflash]

My post in the "First Flight" corner of this forum is coming closer and closer =)

Yesterday we performed highspeed-tests at an local airport. After some slower runs I was sure that the gear was totally able to deal with the 1300m bumpy grass runway.
First we decided to go for speed without me trying to pitch the plane up. This led to almost 80kph speed on the grass runway - without any problems. Even the slight gusts from the side didn´t mean any problems to us.
A short time later I decided to try to pull up when I feel that the plane is just jumping from bump to bump - This resulted in a state of hover at 55kph. Unfortunately the wind direction had changed to crosswind from my right. This resulted in a drop to the left after hovering up so I had to reduce thrust and stabilize again. The windspeed was indicated to 4 - 6m/s in gusts from 95° right of my plane.
Even so it was a great experience to feel how the vibration of the wheels stop with this great power in my back only controlled by my body...

I hope the video can transfer at least an idea of this :)


https://www.youtube.com/watch?v=Gv-GJngJUD8

[team_skyflash]

I have now finished my report on the 'First Hop' test day and published it right here:
http://www.skyflash.org/Slideshow/Project-Skyflash/Test-Reports/test-reports.html

Would be nice to have some Feedback. I hope there are not too many mistakes in it :-)

[team_skyflash]

We are working day by day and finally we are coming closer to the first flight. Currently we are in the 'Delta'-testphase. Delta includes several highspeed runs as well as a lot of different tests and crosswind-runs. Yesterday we were able to make a big step forward when our pilot slightly rotated in heavy 7m/s (15,5mph) crosswinds to test steering and control-ability without any problems. He was able to keep himself stable on the just 6ft wide track chosen for the test.
We made a short video of those tests which you can find here:


https://www.youtube.com/watch?v=UxqaeLiJ_Ek

I´m looking forward to the next tests which will be done on a former german airport with lots of space and free and wide runway. I´ll keep you updated!

[team_skyflash]

Hi everybody,

it´s been quite a while since I´ve posted my last update so I wan´t to tell you the latest developments =)

After reaching our 'First-Hop' we had to check several aspects like side-winds and gust behavior. After finishing this phase we began the next step which was unmanned.
To check the flight-stability and final take-off speeds the pilot was replaced by 160lb steel. This configuration was then thoroughly tested and developed. After fixing some problems with the gear and several tests we went for the first unmanned flight which was covered by the Discovery Channel joining us from Canada.
At 70km/h the Skyflash took off, reaching a height of 1,50m while covering a distance of 35m before touching down again. For us this self-stable take-off on a worst-case grass strip means a lot!
For the project it means that we can go for the next step, which will be an RC-controlled flight on the Skyflash´s own engines. Together with new partners we figured out some ways to RC-control the airplane. We now have UAV-engines with even more power and reliability.

Here´s our first unmanned flight:

http://www.youtube.com/watch?v=qC9j0k8NoWA&feature=youtu.be

Greetings from Germany!

[Frank Giger]

Ausgezeichnet!

I love how multi-million dollar wind tunnels were replaced by a SUV and a long cable - it shows the team is practical and thinking about the simplest way to solve problems (a big boost in confidence on the design).

:thumbsup: