Fighter VTOL 4+1 fixed wing

I don’t think the SERVOx_TRIM matters as they get set during flight when SERVO_AUTO_TRIM is 1. My SERVO3_TRIM is set to1060.

The important parts are to calibrate the ESCs and calibrate the radio tx. to the flight controller using Mission Planner.

Good plan on setting Q_ASSIST_SPEED.

Is your prop a 20x13 ?

Yep radio and ESCs all calabrated correctly.
Just nipped to the workshop to check and the prop is not 20" at all, it is 18x12. The motor box is in another workshop, I will go down soon to check the KV.

Indeed Greg is it a 5015 210kv Prop is 18x12 which apperently is correct.

All the documentation calls for a cruise prop of 20x13. Where are you seeing the 18x12 prop other than what came in the PNP package?

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HI Greg, spoke to the supplyer and he confirmed 18x12 is correct and is what is now shipping with the PNP package. Feels under powered to me. 12s @ 32A max throttle, that is 1536 w. Ordered a 20x13 anyway as I feel a lack of power.

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If you can post a .BIN file of your flight, I can take a look at what the system was doing. The stall speed should be much lower than 20m/s.

Cheers!

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Thanks @GregCovey, looking at the logs I think it was down to me not punching the Throttle from mid stick to full throttle during transition.

I mentioned earlier I was going to order a 20x13 prop. I hadn’t got round to do it.

Have to say a BIG thanks to Ben at @3DXR UK, as he must have read this post, when I got home from the office there was a new 20x13 prop at the door from him. That is simply dedication to customer service. :clap:.

I think everything just went too quickly for my first transition, VTOL flight. New prop on and heading to the field for another go.

@GregCovey, may I ask please, what you have the LIM_Roll set to, the download perams are set to 20 which is very conservative and will take a lot of airspace to turn.

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Live form the field. VTOL flipped 180 around roll and VTOL motors powered it into the ground. One the smoke clears I will take it back to the workshop and do a full diagnostic. Upload the logs if the FC survived.
Strangely enough at the moment more upset with presumably losing my brand new pare of 22,000 batteries judging from the smoke.

I’m very sorry to hear about your crash. It is painful just to read about but I would like to hear more about this 180 degree flip and see your log posting.

A few answers to your questions:

Be careful when using full throttle in FBWA mode as your aircraft may increase in altitude unless your forward flight power system is weak.

My LIM_ROLL_CD is set to 4000 (or 40 degrees).

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Thanks, @GregCovey,
Both batteries lost cels were punctured, hence all the smoke.
The fuselage is a total right-off.
Thrust motor seized.
Lost thrust prop.
VTOL Props damaged
Log uploaded here: - (Edit and photos)
Let me know if you cant download the log from OneDrive.

I need to process the photos to upload them somewhere as they are too big to post directly.

I still have to test all the components but from the Log, I think it is clear what happened. I am not going to say just now as to allow anybody to have a go at the log and formulate their opinion.
Thanks, going home to cry now. :sob:

ACPUK,

I am not sure what caused your crash but my suspicion is that it could possibly be desync between the motor and ESC. Your Q_ASSIST_ANGLE was set to 20 which caused many angle assist events to happen when you were in FBWB mode. Mine is set to 30.

In the images below, we zoom in closer to the fatal angle assist event on the right. The yellow C9 motor looks very low. The question is was this a desync or just the way the plane was tipped. When the
Q_ASSIST_SPEED got below 12m/s, why didn’t the quad motors kick in again?

I’ll continue to look further for the reason…

In the final descent image below, there is an Angle Assist, a Transition Started, and no Speed Assist. I don’t know how the code works here but the plane was going down and not getting assisted by all four quad motors. (as seen in image 3 above)

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So I think my suspicion of an ESC desync is not valid. In this situation, the motor control output (C9 - C12) would be at full value (like 2000) since the flight controller is trying to get more power from a motor that is slipping on the ESC control.

My next suspicion goes back to the flight controller being in some transition mode trying to reach the ARSPD_FBW_MIN setting of 15m/s. Why are C9 and C11 outputs sitting at such a low level when the planes is dropping from the sky?

So here is where the “fun” begins just as the plane was starting to fall out of the sky and spiral to the ground. The speed dropped below the Q_ASSIST_SPEED value of 12 but there was no quad motor action. Was this because it inside a “Transition Started” event?

I will be analysing this all in detail later this evening once I have finished this survey demo.

Note before I forget to discuss, I had to disable assist from forward thrust motor for wind compensation as when trying the first land, motor was powered even just above the ground. Prop would have hit the ground as running. Fortunately I has a table I ended up landing on.

@GregCovey interesting debugging line of thought. Raising more questions in my head, wanting me to get this demo over with ASAP so I can go home and look more into the Log.

HI @GregCovey,
There are telltale signs leading up to the flip, most significantly a heavy undesired left roll at -70 deg at time 1701806 : -


This may just look insignificant but it is not, this is a considerable large ark to the left, sweeping the aircraft 180 degrees. Plotting it in plot.ardupilot (55m20s)you can see the significance of this banking. At this point airspeed was 17m/s, so should not be stalling. (VTOL kicks in)
This happens 3 times during this section of the flight.
This to me would indicate a mechanical issue with one on the Alerons.

The final bank band and flip; Airspeed is 18ms
At the point then the VTOL motors kick in (1758363) the aircraft is at -117 deg: -


The dominant motors are Q10 & Q12 being Rear Left & Rear Right !!!
This is odd as this flips the aircraft tail over its nose.
I would have expected Q10 & Q11 to dominate with Q11 being the higher. Pulling the aircraft nose up and left side up back to level.
This is odd.
In any event, I believe this hard bank left at -117 deg was too late for VTOL assets to rectify the attitude.
I will look at the aileron servos and links in the morning.

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Fighter VTOL has updated the English subtitles

Fighter Aerial Survey UAV Assembly Guide

Fighter Aerial Survey UAV Assembly Guide 1-Partial Assembly of KIT Fuselage

Fighter Aerial Survey UAV Assembly Guide 2-Tail Section Assembly of KIT

Fighter Aerial Survey UAV Assembly Guide 3-Wing Section Assembly of KIT

Fighter Aerial Survey UAV Assembly Guide 4-Aileron and Tail Servo Installation

Fighter Aerial Survey UAV Assembly Guide 5-Power Cable Signal Cable Installation of KIT Fuselage

Fighter Aerial Survey UAV Assembly Guide 6-Installation of Motor and ESC

Fighter Aerial Survey UAV Assembly Guide 7-Preparation for Flight Cntrol Asembly

Fighter Aerial Survey UAV Assembly Guide 8-Installation of Flight Control, GPS, Airspeed ,etc.

Fighter Aerial Survey UAV Assembly Guide 9-Voltage Calibration, Shutter Check, Compass Calibration

Fighter Aerial Survey UAV Assembly Guide 10-Remote Control Setting,Rudder Surface Debugging

Fighter Aerial Survey UAV Assembly Guide 11-Encapsulation, Fixation, Paste Strengthening Film

Fighter Aerial Survey UAV Assembly Guide 12-Multi-rotor Level Flight Fixed Wing Conversion Course Test

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Fighter VTOL UAV Operation Guide adds English subtitles.

Fighter VTOL UAV Operation Guide 1-Mission Planner Survey Ground Station Software Installation

Fighter VTOL UAV Operation Guide 2-Sony A7R Camera Parameter Settings

Fighter VTOL UAV Operation Guide 3-Fighter VTOL Fixed-Wing Assembly

Fighter VTOL UAV Operation Guide 4-Mission Planner Survey Ground Station Route Planning

Fighter VTOL UAV Operation Guide 5-Fighter VTOL fixed-wing inspection before takeoff

Fighter VTOL UAV Operation Guide 6-Ground Station Route Flight Notes

Fighter VTOL UAV Operation Guide 7-Position Data Extraction of Flight Control

Fighter VTOL UAV Operation Guide 8-Image Data Pix4D Quick Spell Check

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My feeling is that the left roll is merely the beginning of total loss of control by the flight controller. In the image below, you can see that the plane was just tumbling to the ground. Even with a loss of aileron, where was the quad motor assist? What version of firmware were you running?

In this image below, the QTUN Throttle Output is used on the first three angle assists but not the last one, creating a fatal fall.

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Currently, there are still 7 in stock at the Banggood USA warehouse and the price has dropped to $568 plus $3 shipping. Promotion Sale From Jun 27 to Jul 6.

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Hi @GregCovey, should we move this onto another thread as it is not an issue with the Fighter and is distracting from the purpose of this thread?

What version of firmware were you running?

V4.0.9

merely the beginning of total loss of control by the flight controller

It would appear this way, I have tested the aileron servos and links and can not find an issue with them.

@GregCovey moved to here

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