I have decided it's time to move up to a large UAV airframe.
I still have the giant payload master in the build, but it is taking forever as if i'm not working offshore, i'm busy test flying ardu-equipped foamies.
I'm going to keep flying the small stuff for now as they are great for ironing out bugs... but they simply can't carry the telemetry gear and cameras that I want to test.
Anyway....I have now purchased a Mugin airframe from FPVflying and it is due here shortly.
Just wondering if there is anyone on here who has one one of these?
I'm looking for information regarding any structural deficiencies and anything else i might need to watch out for.
I'm confident in my ability to assess it's "airworthiness" but obviously it's good to hear from people who've had prior experience with a particular airframe.. eg. areas prone to cracking and parts that wear out quicker than expected.
Cheers
John.
Replies
What is a good cruise speed range for this bird?
Are there any other airframes I should consider that can carry a full sized SLR for 4+ hours?
Depends how you do it:
Near the CG, there is space for about 6L if you were using 1 or 2 tanks. However, I think if you were using a custom tank, or multiple smaller tanks, you could probably get at least 8 litres in there.
You could also put more fuel further forward of the fuel tank area and it should still be fairly stable even after burning fuel, but by that stage you'll be near it's MTOW.
You could also use external fuel tanks, but obviously that adds drag and will require more modifications.
As for speed, it depends on your engine, and we haven't done any testing to map the throttle setting vs fuel consumption, but we can cruise at a very low throttle setting at about 100km/h, or max out at around 180km/h.
There is also now a 4450mm 'super' version of the Mugin if you're concerned about range and MTOW, but otherwise there aren't many commercial alternatives to the Mugin, especially when it comes to price.
I see different figures on different sites, it's pretty confusing.
What do you figure the useful load to be?
I've seen it written that that "Flying Weight" is 25kg, that must be the MTOW.
I see the "Load Weight" as 8kg, not sure if that includes the 5kg that 6.5L of has should weigh.
So my question is, after filling the tank, can I add another 8kg or 3kg?
I'm definately considering the big 4450, but it's a real beast to transport and costs 2x. Plus, no one online has built/flown one and I don't want to be the first.
My reply got mangled for some reason, but here's a v2 of it:
My understanding is:
MTOW (25kg) is comprised of:
Load weight (payload) = 8kg
Fuel = 5kg
Airframe = 10kg
Engine = 2kg
(All approximated of course)
I base this on the fact that my team's Mugin weighs something like 17kg with GF55ii engine, modifications to the airframe, avionics and 3L of fuel.
Some things to note though:
1. You will need to replace the landing gears with metal ones, and pretty much immediately; the fibreglass ones that come with it will not survive many flights; the nose gear will shatter and collapse first and the main landing gear has a tendency to pivot forward and backwards due to it's short base. Our mains haven't broken yet, but they have pivoted and damaged the fuselage. If they had failed a bit more we would have had our prop strike the ground too which would have been nasty. If you have your SLR camera on a gimbal underneath, or just protruding downward, you may end up with a broken camera too.
2. (This is a more a note) Our Mugin did not come with the 6.5L fuel tank (it's a new inclusion), so I don't know how it fits, etc.
3. You'll need probably 75m for take-off and ~150m for landing; our Mugin at ~17kg does take-offs in 60m and landings in 100m (with a ~60km/h ground speed and a very good pilot). It's not too bad, but if you're limited in space, consider making some sort of wheel or air brake system for it.
4. Be wary of operating from grass strips. With metal landing gears it might be alright, but even then, I'd probably want larger wheels and would want to be landing on sports field rather than the random fields.
Hi John,
This is a great UAV platform. I am using this here in Nigeria. We have about 5 kits and have over 5000 hours day and night flying. We are using these as our RC UAV trainers. I am planning to install one of the Mugin with the Ardupilot. I don't know how it will suit it. Do you have any suggestions to this. Have you already installed one?
Hi Waqas,
Obviously I'm not John, but my team has been utilising the Mugin 3m v3 with the APM 2.6.
To mount the APM we created an avionics board (made of balsa wood and depron foam) that sits inside the fuselage and is mounted on top of stratocell foam blocks about 40x60x40mm (W,L,H) (that foam was selected simply because we had some available and it be believed it would approximately the right level of rigidity / flexibility).
That combination works quite well and we have very little vibration, which the APM is easily able to cancel out using software. Andrew Tridgell has stated as well that there's a good chance you could mount the APM (or better yet, Pixhawk) to the fuselage (and the software's artificial dampening would suffice), but I wouldn't recommend it, as at the very least, it creates the risk of having your APM / Pixhawk coming mechanically loose.
On our airframe we've had a pretty good experience (in the past, users of previous versions of the Mugin like Canberra UAV have lost a landing gear wheel, etc), but even still, we have actually managed to have plywood layers vibrate apart; that has only happened on the small piece that wasn't glued particularly well (and it didn't have much surface area to attach to), but it is still something we will be keeping an eye on as we continue operations.
Hi Joshua,
Thanks for the reply and information. It looks pretty interesting. I am planning for a pixhawk in the system. Do you have a configuration file for the APM. I really would like to know the autopilot tuning PID's which is the most tricky part of tuning. can you help me with some pictures that could help me design the autopilot mounting. Thanks
Waqas
Unfortunately I don't have the configuration file available to me for the next few days (Easter long weekend), but afterwards I should be able to retrieve it.
As for the internal mounting, here are some (sorry for the poor angles though) that are somewhat recent.
Note that even the last one (the most recent) is old; we since added a post that raised the 2.4GHz RC satellite receiver above our ballast (which is a ~1.5kg bag of lead shot; that's another thing - the Mugin is notably tail heavy) and also mounted our RC receiver onto the side of the fuselage to provide some polarity diversity. We didn't have too much trouble with the receivers either side of the battery box, but during one flight, we had a bad landing (broke the nose gear and damaged the fuselage - see the recommendations of the Canberra UAV team regarding landing gear) that was mainly caused by the manual RC link dropping out momentarily on approach.
That large block behind the nose gear mount is a housing for 4x 5000mAh 3S LiPo batteries.
In the coming weeks / months we intend to completely overhaul the avionics board.
For one thing, we intend to make it a 3D printed design (made of ABS) that will roughly resemble the existing design, but exploiting the strength of ABS to create something that will provide plenty of airflow, integrated cable management as well as more secure mounting points for electronics.
For dampening we will probably continue to use stratocell foam or something similar, but at the moment those blocks are glued to the fuselage and the avionics board velcros onto the blocks; we don't need to, but we would like a method that is easier than velcro, which has sometimes proven stronger than the glue between the foam and fuselage.
Hi Joshua,
Thanks for the information. I am starting up a new system for the mugin V3. With the pixhawk. And a portable GCS with tracking. I hope you can help me on the PID for the Tunning. Please can you get me the config File for your PID for the mugin. Also can I have your contact number. I would like to talk to you directly too. Sometimes it is faster. Thanks
Waqas
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