TRANSFORMING VTOL EDF JET DRONE (VARITECH) – ROBOTECH PROJECT

[VAALLEON]

This new VTOL design introduces a new concept where the flight controller angle is changed to transform to horizontal flight, via a dynamic mixing algorithm that I call dynamix. This enables the mag and horizon (angle) functions of the flight controller to be fully functional during whole flight, which will make it very easy to fly and perform autonomous missions.

The old flight controller mixing algorithm was replaced with a dynamic mixing algorithm that continuously change the mixing ratios as the flight angle changes.

I use my Split Thrust Vectoring System to navigate the unit vertically and horizontally.

New variable angle wings to improve vertical flight performance while making horizontal flight possible.

Sturdier nozzle wings, to provide better controls in horizontal flight.

If I was younger, I would call this project the "Transformer Project". But I am more a Robotech generation rather than transformers. So, this is my Robotech project and the unit is my new Varitech.

Check out the video to more pics and see how it moves.

MonoPhan Vario – Virtuoso of Thrust ™

https://www.youtube.com/watch?v=N1avXRU63_Y

 

[Gramaphobe]

I am of the Battletech generation, so I have much respect for your project. Keep us updated!

 

[VAALLEON]

Sure Gramaphobe, I'll keep you guys posted! Battletech is as cool. I am still correcting minor but disturbing technical problems before I can increase the attack angle. I will post as soon as I shoot a video worth watching...

 

[JamesWhom]

Awesome looking machine!

 

[VAALLEON]

Awesome looking machine!

Thanks bud!

 

[VAALLEON]

Here’s an update on the project. As some of you know this concept is built on my existing MonoPhan platform, which is a reliable and competent flyer. However, I made many changes to the existing platform to upgrade it to the new varitech.

1- As I mentioned earlier, the software was updated to handle all mixing needs in a dynamic manner, changing the mixing rations with the flight controller angle.

2- I switched from 7.4V to 5V power for the flight controller and the servos (I switched from external battery power to BEC power), to protect the servos from overheating.

3- The nozzle wings were strengthened.

4- The aerodynamic structure was changed by adding the folding wings.

I knew that these were going to have an effect but I could have never guessed it would be this hard to get it to be a reliable flying machine again.

First of all changing the feed voltage required me to change the PID settings. I was guessing that I would have to increase the P, considering the reduced reaction time of the servos caused by the reduced voltage. But it didn’t work that way. My tests showed that I needed to reduce the P setting!

The added lateral surface from the folding wings made the yaw stabilization somewhat tougher. But this wasn’t my biggest problem.

My biggest problem was that, I experienced a high level of instability during rudder (yaw) input in vertical flight. After applying the input and releasing the stick, the unit was moving left, like I applied the roll. I nearly crashed it a couple of times and tested some mechanical changes but didn’t get a satisfactory result. Since it wasn’t reliable in vertical flight I didn’t attempt to extend the wings.

After a painful week of testing, I found the reason that caused this weird phenomenon. Even though the end points of the servo travel was defined in the code, the board wasn’t providing a symmetrical end point to the cooperating servos, which needed to mirror or counter mirror each other. The slight variance in the servo end points was causing the unit to go out of control at situations where the servos were pushed to the end points. This required me to use an external mixer for the yaw mixing and update the code accordingly, which solved this problem.

I also made other changes, such as narrowing and extending the fan nozzle, to create a smoother transition for airflow, from the fan to the vectoring nozzle, and adding larger vanes inside the nozzle halves for a better control. This made a huge difference and completely stopped the fluttering of the nozzles.

Another change that I made was to my transmitter. I transferred the ch5 control to an external potentiometer, which I attached to the top of my stick. This way, I am able to control pitch/roll while I am changing the attack angle. I attached a picture, if you are interested in building one for yourself.

After all these, my 80A ESC failed. So, I am using my 100A ESC for the tests, until I get a new one. Extra weight and worse balance.

Anyway, I added the link for a short vertical flight test video of my fixed varitech. Now it’s time to test the transition and see how my dynamic mixing works

Thanks:

https://www.youtube.com/watch?v=ei7sfketv-w&feature=youtu.be

 

[VAALLEON]

Ok. I remembered very well why I switched to 7.5V from BEC power at the first place, after the flight controller decided to "reboot in the middle of the test flight". I pretty much totaled the varitech right after I took below flight video. I couldn’t believe that the 3mm carbon landing gear bars snapped like a piece of cheap plastic during the crash. The body and the servos were damaged. The folding wings survived for future use.

The unit was rebuilt as seen in the pic with new landing gear and re-positioned original smaller wings for further testing, before going back to a folding wing setup. However, I am waiting on a new variable voltage ubec to proceed with the testing. Simply because 7.5V is too high, the flight controller is not operating properly and the servos are over vibrating/heating in the new setup and 5V has the risk of rebooting in the middle of the flight

These wings are proven to work on this machine and I believe will let me test the dynamic mixing at higher attach angles. However, I feel like I will need to go back to the cross wing design which MonoPhan was born with. We'll see.

Hoping to post new videos as I find the right feed voltage for the new setup...

https://www.youtube.com/watch?v=q5ldOsnnsnc

 

[ExperimentalRC]

Do you have a ubec powering the flight controller? I wouldn't rely on the bec from the esc.

 

[VAALLEON]

When I started using the Multiwii, I had problem with finding the right voltage to feed it. Multiwii boards are designed for multicopters and driving the ESCs rather than the servos. I tried a variety of Ubecs from 5V to 7.5V but couldn't get reliable results. In the end I stared using a tiny 2S lipo to power up the FC and the servos. However, this didn't perform well when I switched over to the folding neck design, because of the setup being vulnerable to vibration.

Now I just received my "expensive" 10A variable voltage ubec which will hopefully help me find the right feed voltage for this setup.

 

[VAALLEON]

This is the test that I did today after installing the new ubec and the old wings.It was a high speed nice flight. I took it to some 20-30 degree angles and found out that the so far the dynamic mixing is good but the aerodynamics are still not right.

https://www.youtube.com/watch?v=ooYbbXXagyI&feature=youtu.be

Here is the reason:

When I switch to the fast forward flight via the stick, like I used to do since I started this project the vectoring nozzle is pretty much still perpendicular the horizon and creating a significant lift plus preventing the unit speeding up too much.

When I achieve the same result by changing the angle of the FC and fooling it to adjust the unit angle, the moment it corrects the angle, the nozzle is going back to the original position, which is reducing the lift and increasing the speed significantly.

This is the difference in flight characteristics and why it speeds up so much with the FC angle variations. It took me a while but I got it. I need more lift on this concept that I needed on the previous version.

Conclusion:

Back to the drawing board for a new wing design.

Thanks

 

[VAALLEON]

Here’s the third wing design that will be tested for horizontal flight.

https://www.youtube.com/watch?v=juSIC4xUxn0&feature=youtu.be

I decided to be on the safe side this time and instead of building a nice looking one with covering material and such, I cut it from a cardboard box The purpose of the first test is to see how the unit reacts to this wing in vertical flight. I never used wings with this much lateral surface on my units. They are a larger version of my classic cross-wing design.

I tested it in a somewhat strong headwind that I would never fly any of my units in, except testing, just to make sure it can handle the new wings in vertical flight.

It handled better than I expected. We had a couple of yaw inconsistencies but it corrected itself without me intervening. Next test will involve changing the FC angle and getting it into transitioning.

I’d like to thank “one or maybe a couple of my followers” who do so just to give ma a thumbs down on Youtube. Looks like you just can’t stop watching my test videos, even though you are determined to dislike them…

But my real thanks are for my followers who are supportive of development and don’t watch my videos with prejudice. I would appreciate if you guys can like my test videos in case you don’t dislike them for some reason.

Thank you very much for the support…

 

[ZoomNBoom]

Ive got to congratulate you on getting the EDF fly reasonably well, but thats not much of a wing. Its more like fins on a rocket, there is no way they will produce a significant amount of L/D in forward flight and the wingloading will be off the charts.

As for disliking the vids, my guess is that its because of the quality of the video, its really bad even for a mobile phone recording, which is a bit of a shame, I would like to see it better.

 

[VAALLEON]

Hi ZoomNBoom and thanks on your comments. I am with you on the wing load, and i know that it will theoretically hit infiniy at hirizontal flight because of the flat shape of the wings. I am not expecting these wings to complete the transition. I am hoping them to go 75-80% into the transition where they will stay at an angle and create significant lift by slicing the air. From experience i know that this concept doesn't like classic wings and the cross wing design is something that i used with success in the past on other units, just not this large.

Thank you for your comments on the video quality, too. I believe its more the wide angle of the lens that is causing the quality issue. But in return it is ensuring that i am able to capture the action without it getting out of the frame. I take a lot of videos and I dont have a designated cameraman

Besides, i would understand disliking videos for poor quality if they were posted for artistic recognition, not flight tests

Thanks for the tip tho...

 

[VAALLEON]

Yep! I just can’t stop building stuff! I decided to no longer torture my bellowed 70mm edf drone with this project and build a new one. One, which is lighter (700g versus 1000g), more agile (my new 120 degree box type split thrust vectoring system), more maneuverable (almost 90 degree longitudinal wings). The funny part is this unit is built with what I had in my scrapyard, re-built analog servos, medium-rare cooked motor, old esc and FC

My major problem with the previous unit was that the yaw lost its responsiveness when I started to change the FC angle and put it to forward flight. The new unit is a monster version of my 55mm 120 degree FPV Triport drone and is a proven yaw champion.

I will add folding wings to this design, which are already designed in the drawing board (in my head), right after I get a feel of the lateral resistance situation in the current state.

You can find the maiden test flight attached. The one that I am talking to my neighbor is a short one, because I somehow used some depleted batteries. The second one is longer and against a pretty strong head wind. This flight is just to test if it will fly and the PID setting. So, as I mention in the video, don’t expect too much!

I know it doesn’t look much like a Varitech right now but I am pretty sure it will teach me a lot, just like every new variety that I build, and will look much cooler with the folding wings when I add them…

Thank you for following…

https://www.youtube.com/watch?v=Q2lySNX7JGQ&feature=youtu.be

 

[VAALLEON]

Upgrades:

1- During the first tests I realized that the 120 degree split vectoring mechanism is not a “nick” champion as much as it is a “yaw” champion. To get over this, the fan body was extended and the distance between the fan and the nozzle was increased by about 1”.

2- Even though extending the fan-nozzle distance helped, it didn’t solve the problem. So I started adding wings to the lower half of the body, to balance out the lateral resistance and create lift in forward flight, in a way that I can tilt the machine to higher attack angles. I ended up with a box type cool wing design.

When I use the stick to tilt the machine for forward flight I got almost to 45 degrees without a major problem. The problem occurred when I tried to get the same result with changing the FC angle. The unit wasn’t very responsive to FC angle change. From the reaction of the unit I could detect that I passed at least 2 dynamic mixing phases and I could see the FC at almost 45 degree angle, without any balancing problems. But because the unit didn’t adjust to level the flight controller, after that point, it lost its balance (because there wasn’t too much room left for gyro compensation, while the FC was using all of servo travel to level the unit). I was able to save the unit, no damage done.

I have 2 options. Either tweak the design of the thrust vectoring nozzles to get a more responsive nick action, or add an adjustable aerodynamic surface to cooperate with the FC angle. I will try the second option first, because there are many good qualities of the current thrust vectoring design that I love, such as light weight, solid yaw hold and simplicity.

https://www.youtube.com/watch?v=UTIHLx5EMsc&feature=youtu.be

Thanks for watching.

 

[VAALLEON]

I crashed it yesterday. Surprise? Nah! I always do it I took off all of the added wings and put it on the table, trying to figure why it just don’t tilt and beat the airflow the way that my other unites do. While I was looking at it with empty eyes, IT CAME TO ME!

It is something that I actually know very well, but for another reason. From the beginning of the Mono-Phan project I learned to keep the center of gravity high, because it helped with wobbling and balancing. And I kept that rule until this unit. But while testing this unit, I realized that lower center of gravity didn’t effect this new thrust vectoring design in a negative way, in terms of balancing, and I kind of liked the idea because it provided a more uniform weight distribution.

However, apparently this was the very reason that the unit refused to tilt despite all those added wings in the lower half. “It was not able to lift its back!” Below test flight is after I fixed the unit and raised the batteries to the top. The difference in flight is like night and day.

I know the video sucks and it goes out of the frame quite often and I apologize for it. But you can clearly see it lilt to about 45 degrees in many parts. I also find it kind of cool that I can simply fly it towards myself and catch it in the air at the end of the flight. You cannot do that with any other machine of this size (that I know of)… And the best part is, there are 2 parts in the video that the tilt was created by the FC by changing its angle the yaw was pretty responsive all throughout the flight and it didn’t speed up crazy like my other monster 70mm unit does (1kg, with 4800kv Cyclone Power motor, should give you an idea why it does that).

https://www.youtube.com/watch?v=j9PEuFMjRe8&feature=youtu.be

It still needs some upgrades but it looks like I finally got into the right route… I mean I hope

Thanks for watching.

 

[VAALLEON]

THE PROOF OF CONCEPT:

MonoPhan goes horizontal for the first time!!!

After totaling the redesigned unit twice and saving tens of possible crashes, I addressed the final problem that the Vario unit had last night. Even though I checked it multiple times, I have coded the algorithm to compensate the roll reverse at horizontal flight, which was causing the unit start to wobble, flip and lose control as I was half way to the transition.

I have been thinking the problem to be aerodynamic and working on the wings all along. To be honest, even though it is a very stupid mistake and made me lost a lot of time, I think it helped me to find the best wing design, by letting me test the unit with the wrong algorithm and find the most stable wing design under those circumstances.

After I corrected the error and re-flashed the controller last night, today I took it to 20 degrees attack angle at the first flight without any major problems)) It got so high and far, I almost lost the sight of it. The algorithm and changing the FC controller angle worked perfect and the only reason that I didn’t go to 10 degrees is that I didn’t need to risk it before fine adjusting the attack angle of the wings.

I am very happy to share this with you guys who have been following me on this for a while now. Today marks the day that MonoPhan gains horizontal flight capabilities, while keeping on being a very competent vertical flyer when needed.

Thank you!

https://www.youtube.com/watch?v=5BR62UAZgCI&feature=youtu.be

 

[VAALLEON]

Ok, this is more like where I want to go. The new folding wing design. The previous wings failed to handle flight angle less than about 20 degrees.

These wings turned out to be a beauty. Very smooth transition and better attack angle. Kept it around 20 degrees in this first flight. The servos need a little trimming before I go any further. Still, a very balanced flight…

https://www.youtube.com/watch?v=CxuTdvXTad0&feature=youtu.be

 

[paulshort]

Wow nice. I am amazed how stable it can be off one EDF unit.

 

[VAALLEON]

Thank you paulshort. Getting better everyday