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VTOL -- freeman2100 vertical take-off and landing fixed wing +pixhawk

When I ordered my 13x8 props from FoxTechFPV, I also bought one of their Pixhawk Px4 Air Speedometer units since it was a great price at only $36 with no additional shipping cost. However, the pitot tube received did not match the image so I needed to use one of Mark_Q’s Standard APM Pitot Tube Mounts to fit the older style tube…which I had on-hand.

After increasing the base angle with some balsa aileron stock, I glued the assembly together with Foam-Tac and painted it black. There was plenty of room inside the Freeman to run the tubes into the Pixhawk compartment and connect the I2C via a I2C Splitter so that both the AS Sensor and Compass can use the same port.

On the far right of the bottom image is my USB trigger for Pixhawk mapping.

Looks good Greg.

I am assuming your FPV camera is going in the nose, which is why you didn’t mount the pitot tube there.

Dave

Dave,

Yes, normally the AS sensor would mount in the nose. Both the kit and the case are designed for it.

For me, it’s fun to try different things so I sometimes deviate from the intended design.

Cheers!

I wish you and your VTOLs a Merry Christmas! :wink:

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Merry Christmas Everyone !!!
Greg I see you are using a Horus X10s, I ordered one of them a few days ago. I was wondering if you would share your setup for the freeman on it?

All the best to all of you in 2020 safe flying.
Jim McArthur

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Hi Jim,

Sure, there is no magic in the Taranis/Horus setup other than selecting some switches and sounds for the Yaapu telemetry with mapping. I would recommend reading up on the Yaapu telemetry here and here and consider adding the FrSky Telemetry setup in the Wiki here. It will make the Horus X10 come alive!

Merry Christmas all!

Freeman.zip (1020 Bytes)
wav.zip (194.8 KB)

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Greg thank you for sharing. I did actually order it with telemetry setup. Looking forward to its arrival.
Thanks Jim

Also if you haven’t bitten the bullet on the costly X10 there is a new group in the game with a nice X10 like model for half the price jumper t16 supports open tx and yaapu telemetry.

Looks interesting but I already purchased the Horus, it should be here in a couple of days.
Thanks Jim

I have the Freeman 2100 standard build. We have basically everything working with exception of the current sensor.
The voltage reads out fine but the current reads >50A when on the bench. I suspect that this is simply just a wrong pin setup but since the PDB is built in, I cant really figure it out.
Has anyone else had this issue or know of a way to resolve it?

Have you calibrated the current sensor? Sometimes they are just off and need to be calibrated some are precalibrated by the vendor or they can supply you calibrated values but if they don’t take a look at this video very handy to calibrate voltage and current.

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Along with my well-made load mounting bracket, I received a ventral fin. After checking that the fuselage would still go in the case properly, I decided to mount it. Over the holidays, I spray painted the fin along with the main hatch. The fin was glued in place using Foam-Tac. Instead of tape, I used pins to secure the exact spot while the glue dried. Perhaps the 2100 model doesn’t really need the ventral fin but it shouldn’t hurt and gives the Freeman a better look.

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IMG_20200104_133532b
We have finished out auto tune and are about to attempt a transition.

We are fine with the VTOL_TAKEOFF options and the basics of mission planning, but we would like to hear from others what flight profiles we should expect for VTOL_Land.

From the documentation:
When using NAV_VTOL_LAND it is important to have the right horizontal spacing between that waypoint and the previous one. As soon as the aircraft starts on the NAV_VTOL_LAND waypoint it will transition to VTOL flight, which means it will start flying much more slowly than it does in fixed wing flight. So you need to put the previous waypoint the right distance from the landing point. If it is too far from the landing point then the aircraft will spend a lot of time in VTOL flight which will waste battery. If it is too close to the landing point then it will have to stop very abruptly in order to land.

For most small QuadPlanes a distance of between 60 and 80 meters from the last waypoint to the landing point is good. For larger faster flying QuadPlanes you will need a larger distance.

We are wondering what sort of distance from the the last waypoint to the landing position we should be using for this airframe with out stressing it too much. Obviously we want to keep it as short as possible and have to factor in headwind, payload and altitude.

I use ~200ft, with a well loaded airframe. Anything shorter than that and it tends to overshoot, longer than that and it stops short of the point and then wastes battery by hovering around.

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Thanks for that. That helps a lot. What kind of glide slope are you typically coming off when reaching the last waypoint? I have had good success when using a 15% gradient with the Believer and being able to maintain a decent airspeed. I think we may test that first.

I use a flat approach at 150 ft, all descent is done in the downwind and base legs. That way the aircraft doesn’t need to change attitude during de-transition. It probably is worth experimenting with, but I see no need to change my own way of doing it, as it works well.

We have been flying a lot of missions and a while ago decided to stop using auto take off and landings.

A few reasons for that:

  • conditions may have changed. Wind direction or speed is not as expected anymore
  • landing spot is not available anymore
  • any other unforeseen reason

So we decided to use the following sequence:

Take off in Q-HOVER and ascent to 30~40 meter. Switch to FBWA and climb to mission altitude. Switch to auto and start mission.

After the mission, return to landing area. Descent to a comfortable altitude, useally around 100 meters. When the UAV is insight, switch to FBWA and descent further while preparing for the landing area. We usually descent to about 30 meters, nose wind.

Somewhere between 100 to 70 meters from the landing spot we switch to Q-HOVER. Our pilot likes to overshoot the landing area slightly so he can control the UAV, looking at the tail.

This way we have full control over the UAV during take off and landing. When something goes wrong, no need to switch to manual take over.

Of course we are licensed to fly long missions beyond line of sight and our pilot is also a licensed pilot.

We use ping ADSB receivers to monitor the airspace.

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Hey Guys,

I am working on my Freeman build. I am making good progress and have a question for other builders.

On the forward engine mount one side has five holes and the other side has four holes. I can’t figure out what they are for. After mounting the tilt servo and tightly fastening the four bolts, the tilt servo has a bit of vertical play in it, probably 1-2mm. I’d prefer seeing no movement in the tilt servo. I am wondering if I am supposed to use the holes to help secure the tilt servo. Please see the attached images.

Thanks,
Dave

IMG_9781 IMG_9782

Those holes are for mounting the tilt servos. Certain shape style of tilt/robotics servos will have holes that match those and let you put screws in.

Thanks for the quick reply.

I noticed that from Greg’s pictures above.

The tilt servo provided with the kit doesn’t have any holes in it. As far as I can tell there is only one way to mount the provided tilt servo:

The forward engine mount has a rectangular spline (can’t think of a better word).
The cutouts on either side of the tilt servo fit nicely over the spline
The top attaches with four bolts that provide downward force to keep the servo in place. It almost works. But the vertical movement of the servo isn’t good. The entire kit is very well thought out and everything fits together snugly, which makes me think I may be doing something wrong.

Pictures provided.

Thanks,

Dave
IMG_9783 IMG_9784 IMG_9785

Servers by jDrones