First of all some background...
Having spent a good 2 years playing about with an Skywalker, Ursus and a Canon camera running CHDK, and designing my own uav, which actually flew recently ,I have come to the conclusion that flying wings may just be the best type of platform for short range aerial mapping tasks to create DEM, DSM models for GIS purposes.
The Skywalker was okay (but quite fragile, and now in pieces!), but I think it is too small to fit a roll gimbal on it. And I've found that if pictures are taken on a slight angle, it is very difficult to use software to tile them up nicely. this is my best effort, but far from perfect. The roads on the right do not line up as the camera must have been on a 45 degree angle when the picture was taken. (click for larger resolution) - It was taken using an ixus80 attached to an URSUS Airframe
Realizing that I need to use an airframe that can accommodate a stabilized roll gimbal, i started to design and build my own twin boom design. It took 6 months from initial design, to first test flight. It has a wingspan of 2.4m - AUW of 5kg, and a flight duration of around 30 minutes with 2 x 5000mah packs. However it needs a heck of a lot of room to take off and land, something i don't have in the areas i need to take photos.
Picture of twin boom plane...
What are peoples experiences with using flying wings for this reason? I have the following types of flying wings, and wondering which one is the best to begin with?
- jp-si 48" span Zagi
- Scaled up 60" span jp-si Zagi (hot wire cut by myself)
- x8 2m wing
I have been using the 60" wing to test the APM2 and 3dr radios. And was using the URSUS (now in pieces after a nasty crash!) as a test platform to practice with the Canon CHDK Kit.
Here's a few pictures of the wing and camera....(click images for larger version.)
My question is how straight forward do you think it is to fit a roll stabilized gimbal to any of the above airframes?
First of all, I am sorry for not being able to provide you with layout of the part inside as I am now in EU and the drones are in Indonesia (but I will ask my friends there to send it, or you can check out the one of Nguyen. He put a thread on how he is able to fly 114 km with FX61).
I don't use 2 batteries (as Nguyen did) however I use this multistar high-capacity 3S 5000 mAh
I put the camera right at the CG of this plane (where the carbon spar is) so basically I made a hole (for the camera lens) there. The battery goes in front up to the end of the nose. ESC etc goes above the camera (where I also use a coroplast platform for the mounting (I guess it's probably the same idea with your wood board). The Motor we use is a 900kV motor.
With this setting, we are able so far flying for around 45-55 minutes (with such payload) and covering around 350-400 Hectares of an area to map (at the altitude of 350 m which is not illegal in Indonesia, of course after taking all the safety and security measurement).
I hope it's is useful for you for the time being. Just FYI, at the moment I am exploring (and modifying) Ansley Peace Drone (of Ed from Environmental Airlines) as the airframe. as I am working with the local communities where internet access (to buy airframe) is not always available. Also for curbing the cost. However, I see that there are a lot here using SkyWalker (including some friends of mine in Indonesia) as the airframe. 3DRobotics also has this 3DRAero which I think is affordable and fantastic.
During the past days I was thinking to add to my Skywalker X5 wing a bungee hook. This will give me the option to bungee launch the wing ( increase the safety during launch).
Based on your experience where the hook must be located (relative to CG ) ?
There is a group with it; mine is waiting in the box yet
It must be winter as I don't see too much activity on the blog. It will be spring here in Northern BC soon and we are itching to get out and do some more flying.
We want to get the top heaviness out of the X8 to improve performance. We find that we have to make the nose really heavy to avoid stalling. It works great with a heavy nose and is easy to control but it is costly in amperage and air speed as we are always pushing into the wind with our nose up in the air to maintain elevation. We are also finding that our photography is not as flat as we would like so we want to add a single axis gimbal for our camera.
With those problems in mind we worked on an X8 modification this winter and have almost completed an X8 underbody made of carbon fiber and kevlar. There is also an opening where we can mount our gimbal. We are hoping with the deep belly we can lower the center of gravity below the wings and get better performance. The gimbal will work in the roll using APM's gimbal function and a digital servo.
Have not began to use the carbon fiber and kevlar yet as I have never done this before and I am afraid of wasting the material. If anyone has any suggestions how to ensure a good piece comes out of the mould I would appreciate any suggestions before I dig in.
PS That is not my messy shop!
Here are the developments on the carbon fiber under body for the X8. Cleaned up the mold and waxed it to fill in some blemishes. I had no idea what I was doing with the carbon, Kevlar, or epoxy so I guessed my way through it with help from a lot of sites on the web. Made a few mistakes (which I will not make again) but it did not turn out too badly for a first attempt. I must now trim the edges and mount the gimbal which I have yet to construct. The gimbal will also be made of carbon fiber. I videoed the entire process and I will post it on my YouTube page when I have the entire project complete. The finished under body was surprisingly lighter than I expected considering how much epoxy was used and weighs about the same as the foam under body.
Dear Richard and all, thanks so much for these very fruitful discussion. I am really a new kid on the block [just started part-time 6 months ago] in using UAV for mapping and building now my first flying wing with fuselage [based on some of the designs in youtube, thanks very much to rctestflight, flight riot, FPVTromso, Experimental airlines, conservation drones] to carry camera. I have been dealing with a social-ecological issues in particular in tropical rainforest and coastal areas [mainly Indonesia] for years and there is a need of having a rather "cheap", reliable and rather easily operate-able UAV as the idea is to have updates of a forested area more often. I also use opensource mainly. For this purpose I have bought APM 2.6 , and I really wonder if you all know or have any idea if it will work [in particular the way points flight] with DX4e Spektrum transmitter ? Thank you so so much for any inputs. Why I consider DX4e transmitter ? as I attempt to build the cheapest possible UAV Mapper that it can be accessed by "trained" and responsible rc-pilot from the local community members. Thanks very very much and I really appreciate all this sharing knowledge here. Warm regards, Irendra
Hi blog, Apologies for not updating you in a while, here is something interesting I put together recently..
A small reconstruction of three cliffs bay on the Gower Peninsula in Swansea, South Wales...
Using X5 wing, APM 2.5, Visual SFM, and Blender...
Last weekend I have made more flights with the X5 wing and Canon SX230.
Here is the setup and layout:
The X5 wing has 1250g and the CG is with 2 mm in front of the "nipples" marked by the supplier. Adittionally i have the elevons up with 50% of the max trim possible.
Even if i have 2* 2200mAh 3s on the same time on the wing , i'm using only 1. With 1 battery i have around 13 minutes of flight, 11 min in autopilot mode , throttle 47% , average ground speed 65km/h.
Unfortunately I have made a BIG mistake ( not the first one, for sure , not the last one) , i did not checked the mode used for the camera to take pictures, the camera was in landscape mode and all the pictures were blurry... Next time i will have a check list with me and hopefully i will avoid this kind of issue.
For making pictures i have used CHDK . The script is very simple : i am starting the script with lens closed, after 1 minute (this value could be changed from the script) the lens are opened and pictures start to be made at 3s interval. When the number of pictures ( number selected from the script) is achieved the camera is closing.I have discovered that even if i have put 3 seconds between pictures the real interval is bigger ( the focus time, take the picture is an adittional time).So the CHDK (in this format) isn't such a reliable solution, from my point of view.
What settings do you have for your cameras ? I suppose that you do not use Auto mode.
Congratulations Alex on the UAV mapping. I am trying to fly a X5 for mapping too without success... Whiich motor and prop are you using? Thank you!