First APM2 Build for Aerial Photography to create DEM,DSM for GIS purposes - Ursus Airframe
Hi Forum,
Some pictures to start...
Thought some of you may be interested in this build as I intend to build an aircraft capable of 1 hour flights to map large areas in order to Create some Digital Elevation models for GIS mapping purposes. Initially i will be doing this for experimental purposes. I know there are a lot of rules and regulations in around commercial photography etc.
I will be focusing on the following
- Best Airframe for the job, including some brief build information
- Suitable Cameras for the project. (Canon Point and Shoot cameras using CHDK)
- Camera Stabilization - already made a basic pan/tilt gimbal for my Skywalker using the FY21AP
- Ardupilot APM2 Learning with Trial and Error
- Software to create the Digital Elevation models.
I know this is a highly specialized area, but i do have some of the above from asking various people on here (initially posted about this in my blog area, but that was wrong place, so posting here...)
Right where to start...
Airframe
I have selected the Ursus Airframe for this build as it seems to have a large wing and space for enough batteries to give slow, stable flight for up to an hour or more in some cases. It has been talked about on here before
Some Stats...
Wingspan: 2200mm
Material: EPP and wood
I'll try and post more pictures than words.. .as they are more interesting to look at...
Day 1
Airframe arrived, fuselage part assembled,
Day 2
Wooden spas glued into wings, Glass rods glued into tail booms
Day 3
Fuselage glued together, with, wooden wing joiners glued into place
Day 4
Wings joined, APM arrived, sticker stuck to horizontal stab.
Day 14
After a few weeks of tinkering, my APM2 has arrived, And with much help from Chris and Michael I have managed to get HIL mode running pretty well in Xplane 10. I have been familiarising myself with the MissionPlanner as much as possible. Learning how the PID settings work.
Servos implemented, Undercarriage on.
I have also been playing with the Canon CHDK (Canon Hack Development Kit) on an ixus 80 and Intervalometer. Which is how i will be taking the photos from the plane, I wanted to see how long it can take pics for before the battery dies, I took pictures every 120seconds, and it took 81. Review was selected though after each picture, And i will be taking pics quicker than that. I created a time lapse from the window. Not that interesting, but its all part of the learning curve.
Day 23
I have upgraded the nose wheel undercarriage to a more robust strut with steering as well. This should give plenty of ground clearance for the Camera Gimbal
Testing the placement of the electronics, need to decide where to put the APM2, R149DP Futaba RX and the Camera IMU. Plenty of room in here for 2 x 5000 3s lipos! AUW is currently 2.7kg!
Tags: APM2, Canon, FY21AP, GIS, Gimbal, Photogrammetry, Ursus, chdk
Replies to This Discussion
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Permalink Reply by Richard on -
CRASH, Airframe fail!
So the weather was perfect, wind was ~9mph, blue sky - the plane was getting to photo taking altitude and suddenly the left wing snapped about 200ft AGL. Aircraft was under manual control at the time, fortunately I wasn't over the Sea.
The APM2 was on board recording data, here is a screenshot of the flight...You can see the dive at the end!
Here is the wreckage in the back of the car....
Possible Factors -
- Flying the plane a few weeks ago in 37mph wind could have stressed the wooden wing spas
- Too much weight in the fuse
Can't think of anything else,
I was just about to do a nice flight with telemetry log for a first stab at some photogrammetry! back to the airframe drawing board. It is repairable, however the main wooden spa that is enclosed in the fuse is snapped inside the fuse. The Ply dihedral wing joiners have also snapped in the wings, which are going to be a bit of a pain to fix. the only real way I can think of getting this airframe to a flyable condition is to install shed loads of CF and Epoxy. and glue the wings on solid, it will just about fit in the back of the car with the wings on.
Options..
- Repair Airframe with CF and Epoxy, to a stronger condition than before
- Install eqt in the skywalker and try that
- Source a new airframe, preferably twin boom
- build something from scratch....
Thoughts...?
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DeveloperPermalink Reply by R_Lefebvre on -
Oh that sucks. That was a nice looking design. Sorry.
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Permalink Reply by Darro Lin on -
Really sorry about the crash! What settings in google earth do you use to show the airplane images?
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Permalink Reply by Richard on
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I Simply checked the checkbox next to 'Planes' in the left hand side - new plane is almost ready!
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Permalink Reply by James on -
OH!! Rich! that realy sucks, it was a nasty dive. i was afraid from the beginning for the extra weight and wooden joiners.
I hope, all your equip. is unharmed, if yes its a proof that ursus fuse design and foam protects very well the payload!
You have prove, that your hands are capable enough to make things better than before, so give it a try.., or you can just order new wings and replace the wooden spars-joiners with carb ones...
I am really really sorry for your fall, im also glad that it was only foams...
did you get any pics before snapping? or during... :)
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Permalink Reply by Richard on
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Yes, It was a bit unfortunate! but hopefully easily fixable, There are a few large cracks in wing root, and one wing joiner has snapped off inside the wing. The join between rudder and horizontal stab is also gone, so need to epoxy. the wood has actually snapped inside the glued in fuse. Getting a Carbon spa or two across the whole wing is going to be difficult. I may simply glue wings on permanently, and embed 2 carbon spas in each side of the ply joiner.It was a shame to have the airframe fail, As I am inevitably going to have another mishap when i start playing with APM! O well.On the Electronics front, the following has been damaged:5000mah 3s battery ~ £25Futaba R149DP Reciever - Aerial snapped half way along, I can solder, but not sure If the range and performance will be as good as previously. If i have to replace, cost around £40 - so not too bad all in all...but I am also considering a long range rc system to fit into my 9c.... thoughts?Camera and all other gear is fine,After having some time to think about this, As it is summer, I may get another airframe just to get some thing up in the air again asap. I have found a fairly nice airframe that looks pretty good.I am also going to order a Bixler or an easystar 2 so i can start tinkering with APM Grid flightpaths in parallel with my photography learnings o nthe larger airframe...Anyone have any thoughts on Easystar 2 Vs Bixler. similarly priced, both come with brushless motors, inclined to go with the easystar.... purely as an APM test platform.R
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Permalink Reply by R. D. Starwalt on
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Sorry too to hear of the mishap.
If it is a single wire, you should be fine soldering your receiver antenna as long as you strip off as little as possible to make the new joint. After the joint has cooled, cover it with heat shrink tubing for insulation.
If it is a coax cable, that is a bit more challenging but in the worst case you would have to simply replace the entire length of it.
I suspect a single wire. With the small amount lost in a joint,it would almost be impossible to measure any performance degredation without lab equipment. In reality having the antenna flapping in the breeze is more problematic than having the *exact* length of wire that the theory describes.
After the repair, simply range check the system and you will know.
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Permalink Reply by Richard on
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Hi R.D. Starwalt, cheers for the info, I will try soldering it, may lose 1cm or so in the length. I am going to fix the wings back on permanatly, and use carbon strip either side of the dihedral joiners.
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Permalink Reply by Richard on
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New Airframe Purchased! I will be fixing the URSUS, however as we only have about 1 month of light evenings and summer in the UK, time is of the essence! so a nice pre-built plane had to be bought to get me up and running.
Just bought the FPV Raptor from fpvflying -
It looks like it will penetrate wind better, and is mostly pre-built - This should arrive from China within 2 weeks. I am however going to use the skywalker for a while. I am not a fan of the T Tail though, keeps breaking whenever i look at it!
I am guessing a slow flyer is better for AP though, and the URSUS was good for that, but there are so many fit for purpose airframes out there. I really dont want to waste sunny evenings building!
It will fly again though!
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Permalink Reply by Richard on
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Can Anyone recommend a motor for the Raptor? I believe the prop size is 9 x 6 - battery will be a 25c 5000mah 3s 11.1v lipo. Unsure as to which motor/kv rating i need, the longer flight times the better!
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Permalink Reply by Martin Poller on -
Not sure if this is of any help, you might have seen already.
Cheers
Martin
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Permalink Reply by Richard on
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Cheers Martin for the doc. I went for a 3536 1200kv motor with an 8 x 6 apce prop. powered by a 3s 5000mah battery it should be upto the job!
Going to try to do my first APM2 auto flight tonight with the skywalker, No air speed sensor though. Bought it along with a set of the UK 433mhz 3dr radios, but discovered upon arrival that you need expert soldering skills to get either of them working :-(.
Fingers crossed GPS speed will be good enough for it to navigate in wind..! There won't be a camera on this flight, but I will post the flight path KML if it works successfully...
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