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

Hi Vinicius,

I am using version 3.9.11, not 4.0 or 4.1. Just a guess here…perhaps your parameters did not remain static. Can you load an earlier version of your .param file from when the 3.9 firmware was installed?

Lastly, try posting your issue in the Plane 4.0 forum to see if anyone else is using it or create a new thread here on the VTOL plane forum so the appropriate title shows up on the main Ardupilot page.

Good luck!

The problem was a mistake in the Q_TILT_MASK, I was using 4 instead 5.

Did this change during the firmware upgrade?

I believe the parameter is called Q_TILT_MASK, not Q_TILT_BITMASK. My concern with the question above is if the firmware upgrade caused the issue.


Hi @GregCovey,

I update the parameter name.
The configuration wasn’t changed in the update, the value of 4 was made by myself.

I have an another question.

I was reading about qautotune, were the the pitch, roll and yaw axis will be tuned.
This means the auto tune for plane unnecessary or we need to first to qautotune and in flight do the plane autotune ? Or the qautotune will adjust the pitch and roll for motors and ailerons/elevator/elevons ?

QAUTOTUNE is for the quad motors only. AUTOTUNE is for forward flight servos for pitch, roll, and yaw.

I would stress caution on using any AUTOTUNE feature unless you have previously flown the QuadPlane and feel that the default parameters are not sufficient. Even then, I do a small tweak to the PID values manually and check for improvement. Typically, you only need to adjust the P value slightly for each axis.

I will ask Mr. Chang for the Freeman PIDs and post them here. I’m curious to compare them against the Nimbus 1800 PIDs.


Anyone? Have I got it right when selecting one of these for the rear motors for a Freeman 2300 at 6,1 kg take off weight?

  1. T-Motor MN4014 KV400 4-8S 30A 171g with cables 900W
    50% 1530g (17x5,8")
    100% 3360g (17x5,8")


  1. KDE Direct KDE3510XF-475 KV475 4-6S 30A 120g 665W
    50% 1580g (15,5x5.3")
    100% 3520 g (15,5x5.3")

And what is a suitable KV for the front motors in a 6,1 kg Freeman 2300 in a 6S-setup? Around 500? What safe thrust is enough for throwing from hands? 1,0?

Asim, I have used Pixhawk 2.1 + Mauch Sensor Hub X2 V2 , Mauch PL BEC + backup-BEC, 2x PL-200A Sensors. Measuring from BEC from PDB where both batteries are connected. But I dont get how they have thought about which one to use between the two sensor-values that came on a little piece of paper for each sensor.

Not sure if this is off topic.

But has anyone looked into this plane.


Baby Shark VTOL RTF.pdf (440.3 KB)

this company has some really interesting VTOL’s small to fairly large

Not clear on your question. Are you asking how the system decides between the two sensors?

Which setup are you using?

this is my setup using V3 not V2.


Mr. Chang sent me the parameter files to be used as a guideline or reference. I posted them below.

I have gone through the parameter file differences with my own and did not find many changes. I believe the AHRS_EKF_TYPE change comes from using different Pixhawk hardware. For forward flight, they are using higher P values so I may change to those. Their transition speeds are slower but aided by custom firmware that I prefer not to post until I test it, if needed. The modified firmware improves transition stability.

Parameter File Differences

Greg’s Parameter then (MFE’s Parameter)


ALT_HOLD_RTL,10000 (-1)

BRD_TYPE,2 (No Entry for MFE)

PTCH2SRV_D,0.04 (0.1)
PTCH2SRV_FF,0.4 (0)
PTCH2SRV_I,0.15 (0.2)
PTCH2SRV_IMAX,3000 (3000)
PTCH2SRV_P,0.7 (1.5)
PTCH2SRV_RLL,1.15 (1.3)

Q_A_ACCEL_P_MAX,110000 (30000)
Q_A_ACCEL_R_MAX,110000 (30000)
Q_A_ACCEL_Y_MAX,20000 (27000)

Q_A_ANG_PIT_P,6 (6)
Q_A_ANG_RLL_P,4.5 (8)
Q_A_ANG_YAW_P,3 (3)

Q_A_RAT_PIT_I,0.35 (0.2)
Q_A_RAT_RLL_D,0.004 (0.012
Q_A_RAT_RLL_I,0.4 (0.25)
Q_A_RAT_RLL_P,0.4 (0.3)
Q_A_RAT_YAW_D,0.07 (0)
Q_A_RAT_YAW_I,0.08 (0.18)
Q_A_RAT_YAW_P,0.7 (0.3)
Q_A_SLEW_YAW,3000 (6000)

Q_ANGLE_MAX,4000 (1500)
Q_ASSIST_ALT, n/a (20)
Q_ASSIST_ALT_MOD, n/a (18)

Q_LAND_SPEED,50 (40)

Q_TILT_MAX,65 (32)
Q_TILT_RATE_DN,50 (12)
Q_TILT_RATE_UP,200 (45)

RLL2SRV_P,1 (3)

YAW2SRV_INT,0.3 (0.15)
YAW2SRV_RLL,1 (0.8)

MFE Freeman 2100.param (19.5 KB)
MFE Freeman 2300 .param (19.5 KB)


You need to enable the BATT2_MONITOR parameter and a second set of battery parameters will become available.

Yes, that sounds correct. Use the 2300 Configuration List to reference the motor Kv needed. Max take-off weight is 8kg.
Freeman 2300 Configuration List.pdf (74.9 KB)

Yes, those designs are very nice but they are expensive and require assembly/disassemby at the field. Do a search for Mugin VTOL. The “Shark” label is for FoxTechFPV.

Asim: Im using the same setup as in your attached picture, but not the PowerCube. I am using a Mauch PL 2-6S / 1x BEC to power the Cube and the Hub. What I meant and what I forgot to mention was that when setting up the power monitoring in Mission Planner (BEC on Power1 and BackUp-BEC on Power2 and third backup on rails) you can use only one of the small papers with values that came with the PL-200A-sensors, which one should I use? They dont have the same values. Both sensors are connected to the Hub and this one is powered by the BEC that is getting the current/voltage-sensorsignals from the Hub and bridgeing them/one of them (?!) through to the Power1 on the Cube. Are you going to use Mauch Dual battery redundancy with the Sensor Hub in the Freeman? I thought of this idea but may skip it and run on only one battery.

GregCovey: BATT2_MONITOR monitors the Cube’s Power2-port, right? There I got the Mauch BackUp-BEC which only have ground and power, no sensor-signals for current or voltage. But I guess the sensor-signals from the other PL-200A-sensor can be connected to the Power2-port sensor-signals inputs instead, and use BATT2_MONITOR using the other piece of paper with values (whatever this values are called, Amperes per volt and Voltage Divider if I remembered it right).

Max takeoff-weight for the Freeman is 8 kg but it will never get that heavy for us, thats why I am trying to find another motor-setup that works well with the aprroximately 6,1kg weight which is a lot less than 8 kg. My goal is to have rear motors that hovers at just under 50% PWM with 17-18" propellers and front motors that are suitable for the 6,1kg weight and still power effective and can transition easily and safely. Thats why I was wondering what power-to-weight-ratio is needed. 1:1-motors in the front would make the Freeman hover nose up, but should it be more powerful or less? I dont like handlaunching weakly powered planes, thats why I dont want the Freeman to transition with a huge dip. :slight_smile: But I dont like putting on over-powered setups either, they are heavier and/or draws more current. The Believer we use with KDE Direct-motors have a power-to-weight-ratio at litte above 1:1 (more power than weight). But I dont know how much, the propellers we use are not in any performance datasheet ( https://cdn.shopify.com/s/files/1/0496/8205/files/KDE_Direct_XF_CF_Brushless_Performance_Testing_-_KDE2814XF-515.pdf?7734511287488513374 ) and we use APC 11x5.5". But they should be almost the same in thrust as the mentioned 12.5x4.3", maybe a little more powerful. Believer weight is 4488 and motors with 12.5x4.3" reaches max 4720 gram. And I dont find any performance datasheet for the MFE-setup for the Freeman either.

I think I found a suitable front motor for 6,1 kg Freeman.
KDE Direct KDE3510XF 475KV
4-6S 30A 120g 665W and with 15.5x5.3" propeller 1580g (50%) and 3520g (100%), each.
That means it hovers under PWM 50% and can do powerful transitions without much dip at all.

And when flying it will only draw

  • 1.2A per motor if using 25% power
  • 3.5A per motor if using 37,5% power
  • 7.1A per motor if using 50% power

50% power in a mission is around 14,5Ah -> 1x 6S 10000 @70% will fly max 30 min which is enough for a mission (longer time if using less current), have to fly within 500 meters in radius, thats not a big area anyway.

Am I right?!

  1. Can you post the pic of that paper of PL 2-6/1 x BEC. I am not using those, but by looking at the specs that is just a step down regulator to 5.35V / 3A, so whatever values Mauch has provided on the paper are just factory test results values after the manufacturing was done. Standard process.

  2. Now the PL-200/8 200A - 7/20 sensor comes with a paper where you will see two values under heading, “Calibration data”, V divider and A/V values. e.g. 26.65985 and 61.90232

a) Run Mission Planner, go to setup tab, select optional hardware and then select battery monitor and you will see this;

i) V Divider value will go into 3. Voltage divider.
ii) A/V value will go into 6. Amperes per volt.

b) Repeat the above process for other battery Monitor 2

  1. I am not building Freeman, I am designing my on VTOL from scratch.


  1. The little piece of paper (printed Excel) is just the values for the Amperes per volt and Voltage divider that are measured/calibrated by Mauch from their test results and they are not for the BEC, they are for the PL-200A-sensors. And they differ between both PL-200A-sensors.

Anyway, for example, the values on mines are:
For No 1 PL200A: Voltage divider = 26.63713 + Amperes per Volt = 62.54576 (this on is on S1 on Hub)
For No 2 PL200A: Voltage divider = 26.68723 + Amperes per Volt = 61.81918 (S2)

Sensors I use: https://www.mauch-electronic.com/pl-xxx-sensor-boards
BEC i use: https://www.mauch-electronic.com/pl-2-6s-bec

But in Mission Planner, Battery Monitor 2… what port does that one monitor? Doesnt it monitor Power2 on Pixhawk Cube (I just realised they call it Power Cube and meant Pixhawk Cube when saying Cube) for example? What do you monitor in Battery Monitor “1” and in Battery Monitor 2? If you use the Power Cube, I see it connects to both Power1 and Power2, but I dont use Power Cube. Power2 on the picture above with the PoweCube dont have the Current and Voltage-signals to the Power2-port.

It monitors Power 2

What do you monitor in Battery Monitor “1” and in Battery Monitor 2?

You are monitoring the voltage of each Lipo.

have you read this article?

Well, I dont have the Power Cube which have cables to both Power 1 and Power 2 on the Pixhawk. Therefore I cant measure anything on Power 2 like you do. The Hub Sensor monitors both PL-200A and if they differ, the larm goes and the RC-transmitter on the ground starts larming (using Futaba EXT Volt to measure the combined LiPos voltage (parallel) on the PDB).

In Battery Monitor 1 I monitor the power from the BEC (1x) which is connected to the sensor hub. I guess the BEC got the current and voltage from the Sensor Hub since it doesnt have its own measuring of current and voltage?

Battery monitor 2, I dont use that one. I dont monitor both LiPos on my setup, cant do that with Mauch BEC 1x.

The link you gave, yes. Works fine. But there is not information on using Mauch for Battery Monitor 2. For that, I still have to use another BEC. We should have used 2X ( https://www.mauch-electronic.com/apps/webstore/products/show/7594507 ) instead to power both Power 1 and Power 2 and then we would have Battery Monitor 1 and 2. But… if that BEC 2X dies, there wouldnt be any backup BEC to Power 2.

I dont remember if there was any BEC 2X when I built the first Vulcan Hexacopter in december 2016… I guess thats why we used BEC + Backup-BEC. And still use that setup on the newer octa. Maybe time to upgrade in the next one. :slight_smile:

But for the Freeman (the VTOL in this thread) we dont use dual battery. Dont need to anymore. One battery is enough.

Details for connecting the Power Module (single or dual battery) for the Cube can be found here. I use only Pixhawk v2.4.8 (aka Pixhawk 1).

You will want more pitch on the front motors. Use 14x8 to 15x10.

It is odd that you got two papers for the 1x. I would use the Get In Touch contact page at Mauch and ask your question. Be sure to put your order # in the message.

Have been using Mauch in several multicopters (dual and single bat), planes (single bat) and now VTOLs (dual and single bat). Works fine and have worked fine for years. No problems. The only problem I was wondering what values to use from the two papers… and they dit NOT came with the BEC! They came with the PL-200A-sensors. Have said it several times. It is someone else who percists saying they came with my BEC. :slight_smile:

If you use ONE sensor, use THAT sensors piece of paper to enter voltage divider and amperes per volt into Mission Planner Battery Monitor. It doesnt have anything to do with the BEC.

I did contact Mauch a long time ago to find out which values to use but they never answered. All multicopters works splendid so it is not that important anymore, but when it came up in the thread, I had to ask. Sometimes its best to just continue and get things done if there are workarounds or if it works great anyway. :wink:

But regarding the Freeman and front propellers, yes should use suitable propellers. Maybe I have to change motors for front to accomplish that. What range of PWM is OK to hover the front motors in? 40-60%?

Yes, that range would be ideal. Sometimes the payload, motor Kv, cell count, or prop size/pitch forces us beyond that range and things still work fine.