The FrSky radio link is bi-directional so you can get warnings for low RSSI and SIGNAL LOST. These can be using the default values on the transmitter setup or customized for your own preference. The manufacturer spec for the Taranis X9D and X8R link is 4921’ (1.5 km). I’m not sure if the Horus changes that but it does allow for a better external antenna to be mounted. I don’t think the redundant receiver extends the range but rather makes the link more solid from all plane angles of the radio link. I have not tested a Tx. failsafe but only a loss of sight failsafe using the RTL mode. That was scary enough. I have flown planes until they are just dots but I’ll typically fly line of sight, even when mapping.
I am still using ACCST because I have had no issues with it over the years and rely on Ardupilot telemetry over the FrSky Sport using Yaapu. My second telemetry link is the normal 3DR link at 900MHz. Sometimes, I use an RFD900 link at the base station which gives you something like a 5 mile (9km) coverage.
When using the RFD TXMOD, you are already using a PPM stream to the flight controller to control the radio functions so you cannot have a secondary SBUS connection.
I will probably go down the route of the FrSky Receiver and Satellite as my primary Tx control although maybe try some of the Archer Access offerings for which the range is stated as >2km. Plenty of range for VLOS flying.
After some consideration, I have now decided to go for 12s and ordered the corresponding motors in China.
This is associated with higher acquisition costs, but the aging of the batteries should be lower compared with 6s, since the current per Li-cell is significantly lower.
I am not sure yet which ESCs I will take and also not yet whether I will install separate batteries for the quad motors. The latter I want to make dependent on the current when hovering and of course on what @Christian_H will report.
The RC remote control and limited MAVlink telemetry will run via TBS-Crossfire (https://www.team-blacksheep.com/products/prod:crossfire_tx). A second MAVlink connection will be installed via LTE 4G with a raspberry and UAVcast software (https://uavmatrix.com/product/uavcast-pro/). Both had been successfully installed in the Mini Talon Quad.Since there is enough space, a LIDAR altimeter and a RTK GPS will go in, so that Next summer the Fighter should be able to drop a 6 pack Budweiser with centimeter accuracy
I like your Budweiser goal! Perhaps there is a new market to compete with Amazon.
The current draw on a 6s setup doesn’t seem bothersome. With all 5 of my motors on for a transition (worst case), the current is still under 100 amps on a 6s, 21AH pack that can deliver 630 amps continuous. The duty cycle for this is very low.
I haven’t found a use case yet for flying with RTK so I am interested in what brand you chose for your setup. My M8N GPS units all seem to work within a few feet to a yard or meter from take-off to landing. Perhaps it may depend upon your location but I am not certain. I am looking at this NEO-M9N receiver with MultiPatch antenna from the GNSS Store. The M8N modules I bought from them years ago are still working fine.
I tried a test with the Matek M9N-5883 NEO-M9N GPS Module on my Pixracer 250mm quad and it worked quite well. I would like to hear your thoughts on using an M9N module versus an RTK system.
Together with a laser altimeter I have measured the altitude differences of the runway on our model airfield and in the approach corridor.
In my region a close meshed NTRIP correction signal is available free of charge. Missionplanner (GCS with internet access) then sends the correction signal via Mavlink to the flight controller. Herewith a RTK-FIX with basic setting of Arduplane is easy. The position accuracy is actually in the centimeter range. The M9N, on the other hand, is in the single-digit meter range. Tridge had made extensive comparative measurements: Big GPS Round Up
Without correction signal, M9N and F9P are certainly not far apart.
I expect that the Fighter will really land with decimeter accuracy and not with “accuracy” of several meters when landing automatically.
Hi Rolf,
I’m very interested in range finder altimeter, particulary what find of forward offset you would use and altitudes you intend to fly at. I have a use case for flying a a set height above terrain. My plan was to fly the mission twice. First time to map in RTK and upload custom GEOTIFF and then fly the precise altitude using terrain follow in MP.
Hi Steven
I have used the rangefinder altimeter in fixed-wing aircraft only for automatic landing. LIDARs with a range of a few meters are sufficient to define the flair point exactly above the runway. I did not use it for terrain following. In the fighter, the LIDAR should also point vertically down and show the Q_LAND_FINAL_ALT exactly above ground.
Hello @GregCovey, @Rolf,
Finally I also just put order on this Fighter. I have important question about PID tuning of the plane mode, especially for Roll and Pitch… Based on default parameter of the plane FW 4.09 , value of the basic PID value for Roll P:1.0, Pitch 1.0 (PID of the Plane mode). I checked that last time you did posting “Gregparam3” file (CMIW), and value of those parameter is 1.2xxxxz
My question is, did you do Autotune (plane mode)?? Or do you think that default PID setting is good enough ?? Could you share your latest parameter (stable in plane mode)…Thank you…
I didn’t use the default PIDs and I didn’t use Autotune. MFE provides the PIDs in their on-line documentation here. I used their PIDs (copied into my .param file) and they worked great for both hover and forward flight modes.
@GregCovey,
Thank you very much… I have checked the parameter, and found it is not much different than default PID of the FW 4.09 …I also tried similar parameter for my previous VTOL, and it work good. I am curious if anybody has done Autotune in Plane mode.
Unfortunately, the engines have not been shipped from the MFE store.
MFE told me via Aliexpress that due to the “pandemic situation” they only ship by expensive air freight to the euopean union.
It’s not worth it price-wise, I will therefore look for other motors.
Hello @GregCovey,
Hope you are fine…Just to share my experience using the new Matex M9N gps with Can bus. I only get maximum 16 sats., while my Cuav Nero pro (and also the Holybro Pixhawk 4gps) can get up to 30 sats. (I use dual gps system)… I am a bit disappointed with Matek M9N performance . I think Cuav Neo pro with Compass RM3100 is excellent… Have you tried the other M9N from GNSS store?
The NEO-M9N chip has an issue with only allowing 16 satellites if the update rate is greater than 5Hz. This is a limitation of the NEO-M9N chip and not the Matek M9N GPS module. If you keep the rate set to the normal 5Hz then it will work.
No, I haven’t transitioned to my winter mode yet of ordering new stuff to play with. My interest in the NEO-M9N from the GNSS Store is in the size of the multi-band patch antennas for larger VTOLs. They are clearly larger than the 25x25.4mm patch antenna in the Matek M9N-5883. The 25x25.4mm patch antenna works just fine in the U.S. and seems appropriate for smaller models.
Do you know what the patch antenna size is inside the CUAV antennas?
Hi @GregCovey,
I have checked the parameter setting of my Matek M9N is 5Hz which is default setting and I did not change it. So with 5Hz I got only 16 sats max. About Cuav Neo3 Pro, I am sorry, I have not got the antenna size yet… But ii is a bit smaller than the Here3 Gps… It is a bit bigger than Holybro Pixhawk 4 Gps. BTW, Holybro Pixhawk4 GPS is also very good. I got more than 25 sats, while Matek M9N only got 16 sats at exactly same condition…
Regards,
Due to the shipping problems of MSE motors from China to the European Union, I looked around for 170kv 12s quad propulsion motors available here and came across the 170kv T-Motor MN601S, which I have now ordered from a dealer in Spain who has them in stock.
I have ordered my Fighter and am looking at going with KDE motors and KDECAN esc’s (don’t look at the price). Since I don’t have the kit yet can anybody please confirm 21.5" props for VTOL will work/fit - Hover thrust 13.6Kg. I will be running a Parallel 6v system with multiple redundancies. On the front plan to run either T-motor AT4120 KV500 with 16/12 prop or AT4130 KV 450 with 17/10 prop (Over Kill?).
