My "VTOL" Voyage finally making progress?

[L Edge]

Have you ever had a project that has kicked your butt? I chose the VTOL bi-copter approach 11 years ago, 7 years ago, 1 year ago, and now. Vibrations, stability, and lack of experience with the software got the best of me time after time. Well, I am back at it and making progress.

Always looking for a VTOL plane that doesn't exist, decided to make one where there are no physical surfaces for aileron, elevator or rudder control and yet fly. So this is it.

Notice the two servos, that is the key to horizontal flight. To have pitch, both servos go up or down, roll has one servo go up and the other down, and yaw uses differential thrust by changing RPM's.. Does it fly and can it take off vertical? Heck yes, with ease. Can it have a controlled takeoff and land? That's the problem. Forward flight is rather easy, hovering(wind) and landing, not so.

Can a gyro work? No, because there is a vert to horizontal which is called the transitional stage. This allows you to maintain a lift/thrust hovering/flying conditions at all times to control the aircraft.

11 years ago, Open Aero VTOL V1.6 software using a KK2.1 board with help available. Over time, it dropped out of production so only help was booklet. Anybody who has explored software and puts the wrong value(s), it ain't going to work. So struggle it is until "eureka", so now I hope to go one step forward and stay, not 2 back.

If you look at the vert picture(ship is called EYESPY), to lift off and hover, you add throttle and hold it fixed once it is off ground.
To pitch down, it moves away from you, pitch up, it comes to you. (Both servos move same direction)
To rotate about itself(roll), right aileron brings the left corner counterclockwise. (Left servo comes at you, right moves away)
To move plane to the right(yaw), the rudder is pushed to the right. (Remember, if throttle moves a click less, down you drop) Servos don't move, right motor decreases)

So while I practice in the cellar hovering( finally solved P,I,D's) and now tweaking, here is horizontal flight showing it flies, even with gusts.

Still have transition to cover, should be no problem going to horizontal, but other way around controlling decent with wind.!!!!!!

 

[LitterBug]

I have a few that I bought with the intent to tailsit/VTOL, and have meant to build a foamboard wing (FT Dart) to do tailsit/vtol, but have never taken the time to follow through. I have built and flown two bicopters including the EZ Bicopter I 3D printed the main frame and used carbon rods, plus used a 3D printed pivot designed for tricopters. Also built @David Windestål's Bicopter. They flew OK, but really needed a lower CG. Really need to revisit these again, Plausibly for FF '25 and incoporate them into a wing design.

RCExplorer BiCopter Thread

Just when I thought I had way too many builds already, David Windestål comes out with another awesome idea and I find myself working on organizing a build in my head. Here's the Alpha Build he cut, assembled, and got flying during the week previous to flying to Flite Fest Ohio '18...

forum.flitetest.com

 

[L Edge]

Finally nailed it in the cellar. Made about 8 hovers and happy.

Next unknown I got to work on is the transition point that allows you to move away from hovering say 10%(that allows you to hover in a wind where the slab of foam is tilted at an angle by program) and then add power to make the transition to forward flight.
That is why I picked this program and then it will be an outside battle with nature(wind) to see how I do and how good this software is..
Glad I flew choppers when I was younger.

 

[Piotrsko]

For out doors, think you may want bigger diameter lower pitch props like on an osprey but that is just my uninformed guess. Possible issue is lack of immediate thrust changes as motor spins up or down so you would want less expo or more throw. Does the motor offset affect anything? How do you rotate about the centerline without turning or does than even matter?

 

[L Edge]

1) Using APC 9 x 4/7 props and to hover, throttle is about 50 %, to fly horizontal only about 35%. Found the 3/8 pitch lacked get up and go. Especially in the wind. Acts like a chopper in hover.
2 )Motor and battery are in same plane.
3)When vert, aileron just turns it about centerline. It is like tacking, when the wind blows and you break free of the ground, you tilt forward to hover, you rotate plane say 30 degrees with the aileron, you add right rudder so your plane slides right forward and keep pitch nose down to move forward. To shift other direction, quickly rotate aileron to left to 30 degrees, add left rudder to slide left and pitch down to go forward. Plus the throttle has to adjusted to keep same height.

 

[Piotrsko]

Gotcha, the pivoting motors act like a tail rotor, more less thrust acts like adjusting cyclic on one side. Whooda thunk?

Is there a final purpose for this or is it a one off demo?

 

[L Edge]

Gotcha, the pivoting motors act like a tail rotor, more less thrust acts like adjusting cyclic on one side. Whooda thunk?

Is there a final purpose for this or is it a one off demo?

Final purpose is to design a model that doesn't exit, which is has no moving physical control surfaces. All action is up front. Can't find anybody else who has tried it.

So I don't have physical elevons, what is going to happen when going from forward flight to hover(descending) with a wind? X-Vert handles it with set of elevons( it hiccups at times, as I flown it many times) so with moving control surfaces on the top, what is going to happen?
Besides I chose a different way of Tx controls to hover it vertically, so it's going to testing my talents.

Next, is my Photon NYGAD plane, think I have found a solution so you can fly the rudderless plane rather than being in control by a FC unit.
Solved what causes the pitch problem that shows up with those future designs.

 

[LitterBug]

If you did it with a quad, it would be much easier.....

A quad and an x or + wing would be even better.

I didn't realize you were trying to go servoless.... Guess I should have read better when not drowsyat bedtime.

 

[L Edge]

Here is the video of the bi-copter approach for takeoff. Notice when close to ground, prop blast interferes and sends plane everywhere.
Bring it up about 3 feet, settles nicely.

To fly it vertical, motors/prop go to hover. To move left or right, I use the rudder left or right, this changes motor speed and it slides left or right. Remember when the rudder stick is moved, it can't change the throttle position or it climb or drops and your in trouble.

Pitch, both motors/servo move together so push the pitch down and it moves the plane away. Pull toward, plane comes to you.

To roll the plane(aileron) about itself, the servo pitches one down and the other comes up. I set it up so that you want a counter clockwise rotation, give a right turn. Again, no physical elevons, all action is generated ahead of leading edge.

Try it with the video running to see if you could fly it with these controls.
I set up weak hovering so I can practice moving it around and restore control.

 

[NickRehm]

Not a tailsitter, but Tom did a similar thing where he used motor tilt and differential thrust for primary control in forward flight (+ an elevator...but you get the idea). Basically re-used the motor tilting mechanisms from hover like you're doing. It can definitely be done!

 

[LitterBug]

OK, so my bicopter with a wing below/behind. Should fly much better than a bicopter, in forward flight anyway.

RCExplorer BiCopter Thread

Just when I thought I had way too many builds already, David Windestål comes out with another awesome idea and I find myself working on organizing a build in my head. Here's the Alpha Build he cut, assembled, and got flying during the week previous to flying to Flite Fest Ohio '18...

forum.flitetest.com

May need to revive some old hardware..... And join in the fun!

 

[L Edge]

Not a tailsitter, but Tom did a similar thing where he used motor tilt and differential thrust for primary control in forward flight (+ an elevator...but you get the idea). Basically re-used the motor tilting mechanisms from hover like you're doing. It can definitely be done!

First of all, you do some nice "outside the box" thinking and designing.

Like the KK2 software, is has a couple of features that I like going thru the transition which allows you set a time for outward and inward as well as a smoothen throttle curve to assist you.
Secondly, it's set up so you can step a % of each(between hover and thrust flight) in your program in your 3 position switch. I want to fly in wind so the flat plate really needs to be tilted somewhat to hover. The mid switch will allow you the set your hover with a tilt to combat the wind. Once it programed in, it should be easier.

 

[L Edge]

OK, so my bicopter with a wing below/behind. Should fly much better than a bicopter, in forward flight anyway.

RCExplorer BiCopter Thread

Just when I thought I had way too many builds already, David Windestål comes out with another awesome idea and I find myself working on organizing a build in my head. Here's the Alpha Build he cut, assembled, and got flying during the week previous to flying to Flite Fest Ohio '18...

forum.flitetest.com

May need to revive some old hardware..... And join in the fun!

Yes, please do.

 

[LitterBug]

My questions are on motor placement and airfoil choice.
1) With the motors placed in front of the wing rather than off to the sides, can we expect to get "lift" from the wing to amplify the pitching of the motors? Would this also give some roll control when yawing to help coordinate turns?
2) As a tailsitter, would a symmetrical airfoil be better under those conditions for control under most conditions?

LB

 

[L Edge]

My questions are on motor placement and airfoil choice.
1) With the motors placed in front of the wing rather than off to the sides, can we expect to get "lift" from the wing to amplify the pitching of the motors? Would this also give some roll control when yawing to help coordinate turns?
2) As a tailsitter, would a symmetrical airfoil be better under those conditions for control under most conditions?

LB

Before I answer, when you tailsit, are you in earth reference or airplane reference.?
I use airplane reference which is:
ailerons control roll, elevator controls pitch, and rudder controls yaw that's cause I hover.
Earth reference:
ailerons control Yaw, elevator controls pitch, rudder controls roll

See the difference. Can't answer 1 until I am on same wavelength. Your roll could be my yaw.
2) I am hoping it will. I picked symmetrical hoping that on the descent(have no elevons) it doesn't introduce side forces.

 

[joelspangler]

I've considered trying a bi-copter VTOL a couple of times, but have never been able to talk myself into actually trying. I think your idea of vectored thrust rather than traditional control surfaces is a neat one. I'm going to link to a video that explains the issues you'll run into while transitioning between VTOL and normal flight - while the video is for an airframe with normal control surfaces, I'm thinking many of the same thought processes will probably apply.

 

[LitterBug]

I think it would be better to have the control surfaces (elevons) rather than just vectored motors. Pitch authority will be the biggest issue without at least an elevator in forward flight, and probably in transistion. It was the the weak link in the bicopters when I was playing with them too. CG needed to be kept sufficiently low or it would pendulum, or even become completely unstable in the fore/aft directions.

In Tom Stanton's video that Nick linked above, Tom did have an elevator on the tail. So it wasn't all done with just motor pivoting.

 

[L Edge]

I've considered trying a bi-copter VTOL a couple of times, but have never been able to talk myself into actually trying. I think your idea of vectored thrust rather than traditional control surfaces is a neat one. I'm going to link to a video that explains the issues you'll run into while transitioning between VTOL and normal flight - while the video is for an airframe with normal control surfaces, I'm thinking many of the same thought processes will probably apply.

Hey, that's the fun of this site. To see what works and what doesn't. Hope you watch and then try your bi-copter(toughest) and have some fun. This time all it took was one correct P value for me and I am off and running. Thanks for the video, only part I am concerned about is the descent in wind like I mentioned.

You can see Litterbug feels you need elevons, I hope not. To simulate as close as possible, I did 2 experiments.
Flew Eyespy(level flight) around doing rolls, loops, coordinated turns and even a flat spin that didn't loose much altitude. Had control in all three axis.

Second, as a tail sitter, (if gusty wind) probably requires you to pitch forward, rotate plane if side wind and possible slide left or right to keep the plane under control to land.

Look at this video.

.

Hey,, you got a chance. that is my setup when hovering. Long as you know rudder slides it left or right, aileron rolls the wings and pitch down, I improve my odds. You will need fast actions.
It won't be long before I'll say I'm ready.

 

[L Edge]

I think it would be better to have the control surfaces (elevons) rather than just vectored motors. Pitch authority will be the biggest issue without at least an elevator in forward flight, and probably in transistion. It was the the weak link in the bicopters when I was playing with them too. CG needed to be kept sufficiently low or it would pendulum, or even become completely unstable in the fore/aft directions.

In Tom Stanton's video that Nick linked above, Tom did have an elevator on the tail. So it wasn't all done with just motor pivoting.

It really depends what happens in hover or forward flight with your model. When Tom went from FF to hover, watch the ailerons(he calls flaps) come down partially. I thought it was for pitch, he says it was for slowing the plane down.(time1:45)

Best comment from someone who has tried to get it going is "These complex plane don't have a long life.

 

[LitterBug]

Step 1 for me:
Get my intact RCExplorer bicopter out and give it a fly. I had made some adjustments to the mixing a long while ago that never were tested.

Step 2:
Make a wing designed around my EZ bicopter/tricopter plates with extended 10x10mm booms.


I'll hold off on the elevon build till later. I want to give the non control surface a good go first. I plan to use the FT Dart for the elevon plane, and eventually I have a massive flying wing that I'd like to upscale too if the Dart proves successfull.

Cheers!
LitterBug