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May 08, 2010, 06:12 PM
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matthew73's Avatar
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Build Log

F35b.....Joint Strike Fighter.....VTOL attempt


Hi folks, and welcome to my F35 VTOL project. This will be a hard build but lots of fun. I have already started construction, and design continues in both my head and on paper. (No CAD design here im afraid). I cant provide projected weights, wingspan etc, because this project is so much in its infancy. I have started to test concepts and components. Most of these are new to me (e.g twin motor setup, gyros, crazy radio mixing, contra props, thrust vectoring etc.)

Below are some preview images of the build. I will detail my design concept and basic plan of attack for this challenging project soon.
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May 08, 2010, 08:49 PM
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NighthawkF-117's Avatar
This should be cool good luck!
May 08, 2010, 09:15 PM
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v22chap's Avatar
great looking design .... good luck and keep the pictures and VIDEOS coming
Larry
May 09, 2010, 01:04 AM
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Subscribed too.
May 09, 2010, 05:15 AM
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Thanks for your kind words everybody.
May 09, 2010, 06:15 AM
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F35 Joint Strike Fighter VTOL attempt... Basic concept.


Did i say basic?

Okay so here it is. This is not my idea. Ive heard many people suggest and post the same idea before. I hope i manage to make this explanation easy so that people can understand. The VTOL test rig, and perhaps the finished product (if it ever gets finished), will consist of 2 Yaks, or 2 PBFs (Pizza Box Flyers) mounted along side of each other.

For example: Imagine 1 Yak joined to another Yak, wingtip to wingtip. Now get the pair of Yaks hovering, and you have the start of my VTOL platffom. Okay, so lets now imagine that the left wingtip is now the nose of my F35, and the right wingtip now becomes the tail. Theoretically, as the craft slides sdeweays to the left, My F35 is now moving forwards in direction. Whilst in the hover, the Yak's elevaters, when moved together provide role control. When the elevaters move in an apposing direction to each other, then they should influence Yaw control. Im not exactly sure how moving the rudders together will move the craft. Im guessing that it will skid forward and backward. Can't wait to find out. Pitch will hopefully be controlled by a gyro slaved to the throttle of one or maybe both motors (which will have contra rotating props). And thrust differential may be required. I think that among these concepts, the throttle/pitch control will be the most difficult to master.

Pics listed below include:

F35 STOVL prototype. What an amazing piece of machinery. All those bits and pieces moving all over the place. Like some kind of flying transformer. Will it become a formidable and succesfull platform for warfare? Time will tell.

EPPYAK. This is just about the best designed foamie i have ever built. This was made from the plans by LEADFEATHER. Great fun indoor and out. (Highly recommended). Its about 30 inches long and i can hover it without gyros. No problem.

F82 Mustang. The closest thing i could find to a pair of Yaks hovering.

PBF (Pizza Box Flyer). Another great design by LEADFEATHER. Most PBFs are made 18x18 inches. I made mine 20x20 inches (not illistrated). It was easyer to hover that it was to fly level. Got heaps of fully controlable hovering action. The image included is by LEADFEATHER, I hope that was okay to include it in my thread? Later on I experimented with putting my first gyro on the rudder of the PBF. It made things easier. More on gyros later. My PBF has since been relegated to the foamy bone yard and scrapped for components.

VTOL test rig. In this image you can see the beginings of my VTOL test rig. It consists of 2 PBFs along side each other with a panel in the middle. At the bottom you can see the 4 control surfaces that should influence Yaw(outer surfaces), and Role(inner surfaces). Rudders not pictured at present. The motors will mount at the top. If all goes well then I may lower the motors down further. The whole assembly will then sit inside an elongated box with generous openings in the floor for the downwash.

Ive learnt that succesfull VTOL (and especially transition) is way hard. Only a handfull of people have pulled it off really well. And they have way more experience than me. But i have chosen to treat this project as a massive learning experience. Total success may not be required to fulfill my wants. Ive learnt so much in the last 2 weeks. Please excuse my poor spelling. Will include build images and component testing videos soon.

Cheers.
Last edited by matthew73; May 09, 2010 at 08:02 AM.
May 09, 2010, 09:43 AM
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well it looks like you'll probably have the hovering thing handled the only thing i queston is that you really won't beable to transition to full forward flight. this has always been the biggest problem to overcome . i have a frew ideas on how to do this of my own design of course just need the funding to pull it off. i'm als working on the scorpion from avitar but this has the same issue as yours it ill hover but really no full transition to full forward flght like a plane so it will be cool but i feel like i'm falling below the mark of a true vtol like the f-35 or harrier jet. good luck i'll keep watching to see how it goes.
May 09, 2010, 09:44 AM
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NighthawkF-117's Avatar
I get it. Love the F/P-82 also the JSF is a cool plane. Will you be useing gyros? How many. By the way im contemplating a way to build a V-22.
May 09, 2010, 06:49 PM
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I plan to use the Blue Arrow BA-G2H1 Gyro to start with. Ive already flown with them on 3 different aircraft. I get these from Hobbyking. They seem to work fine, their cheap, light weight, and small in size. For the moment i plan to use one for role axis, one for pitch axis (most likely on throttle of one or two motors), and one on Yaw axis. Im also going too experiment with a remote switchable headlock gyro for Yaw axis also.

Gyros are so much fun. Plugging them in and watching them work for the first time is like some kind of Frankenstein moment. Then you tune them to the point that you don't notice them working whilst flying. All of a sudden your plane becomes easier to fly and you forget that you've even got them.
May 09, 2010, 08:02 PM
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RCvertt's Avatar
Very nice build. Looks like you'll learn a lot from it.
May 10, 2010, 03:06 AM
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Build Pics


Im currently building the center section of my VTOL rig that contains my two PBFs. Now that i have those basic dimensions, im able to build the box that will contain them. This elongated box serves the following purposes; It gives the whole thing shape, it provides a large space to accomadate the control surfaces, motors, ESCs etc, it provides structural rigidity, it provides a stable base so landing gear/legs may not be neccessary for testing, and it will contain all components onboard with a little room to move things around. And as you will notice it contains openings for the prop wash.

Below are some pics. More work on the centre section continues. As does testing with gyros.
May 10, 2010, 04:49 AM
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Gyro - Throttle first test...success


gyro-throttle test rig.mp4 (2 min 35 sec)
May 10, 2010, 11:39 PM
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RCvertt's Avatar
Cool stuff.

Any idea what thrust you're getting from it? What KV is the motor?
May 11, 2010, 01:37 AM
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matthew73's Avatar
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Thanks RCvertt.

The motor is a Turnigy 3020 1200 kv, 8x4 prop, 18 amp ESC running on 2 cell LiPo. I seem to remember reviews stating that it will go verticle for a model that wieghs around 350grams. 2 of these should be sufficient to hover my rig so long as it does not gain to much wieght.

My new props have just been delivered to my door. They are contra rotating GWS 8x4 3 blades. I planned to do an amp draw test to make sure that i am not over taxing my ESC. Ive just noticed that these props have a much more beefy centre. Im yet to wiegh them, but as you might imagine they wiegh more than the standard GWS DD 8x4 2 blade prop. And as a result they will not fit my prop saver on these motors. So I will have to choose different motors, and i will have to use alloy prop adapters. If anyting, i will have to get slightly higher rated ESCs if the amp draw on the 3 blade increases markedly. If they draw more amps then flight time goes down, so bigger battery required.

Can you see whats happening here.

I call it the VTOL conundrum.
Last edited by matthew73; May 11, 2010 at 02:19 AM.
May 11, 2010, 02:16 AM
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Gyro - Throttle test rig.


This is the test rig that I used to test this concept. It consists of a piece of pine 45cm long. Mounted on it is a Turnigy 3020 1200 kv motor, GWS 8x4 DD prop, 18 amp Hobbywing Sword ESC, Blue arrow BA-G2H1 gyro (mounted in the centre), 2 cell LiPo, and a Spectrum receiver.

This was a good start. Lets hope my luck continues.
Last edited by matthew73; May 12, 2010 at 01:59 AM.


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