Ok, I've finally found some legs that I'm reasonably happy with, which means "Terrence" (formally known as Platypus) now has his gimbal in situ, and running!
The legs are Tarot's off the shelf, but seem to perform ok. The shape of the frame means they are toe-out, but this aids video clearance anyway, so may leave them as is.
Got the rest of the electronic to connect up tomorrow after fitting the legs, but should be ready for a test flight Friday.
Other notables in this "dot release":
- M2.5's from china have been binned, and replaced with some from Britain. Much better quality, but a couple still rounded. It might just be my allen key, but might also be the inherent limitation of M2.5. I could go to M3, but I'd need to redesign the clamps etc...hmmm.
- Terrence is flying well, but his CoG is well forward of CoT. 40mm forward, with a 10.0A 6S pack. However, this doesn't seem to affect him much! The rate of straight up climb is less than I expected, even with a full camera load. 3m-100m (relative, at starting height of 800m ASL) takes 10-12 seconds, which I think is a direct result of the APM throttling the rear motors to maintain stability. Not that you'd notice - at full throttle it climbs rock solid stable.
- immersion 25mW tx replaced with a 600mW and moved forward because of the legs.
- gimbal vibe balls replaced with harder items. Very secure now.
- a "hybrid" vibe solution is used. 4 x zeal corners suspect a G10 plate, which suspends the APM using 4 3M corners (ie one 3M square cut into 4). More data on this on Friday.
- I added a rubber "anti slip phone matt" into the battery bay. Surprisingly effective at holding the battery in place, and reducing vibes. You still need to velco tape down the battery though!
In short - if all the next tests go well (these are the crucial ones - the gimbal performance - it's what this is designed for!), I'll be looking to get the "gold" samples cut in February for the 3 volunteers from diydrones! (Hughes et al).
* Of Angry birds fame.
Specs please? Your design is basically what I was going for. A medium weight (2-2.5kg), high endurance, GoPro 3-axis quad.
Ok, first of a series of tests now the gimbal is on.
The easiest one - a cold weather test! 1000m ASL, -6'c. A "video friendly" flight, lasting 12 minutes, landing on 3.6v. 12 minutes is way below the target, but room temperature voltage was 3.81v! So very probably acceptable 20 minute performance in more comfortable temperatures. All measurements using a 10900mah.
Flight characteristics are good - very solid and stable and video friendly, but yaw P rate too high for video, and Yaw D rate too low. Gimbal motors need more power and more P in both axis - gimbal was too slow to react to sudden movements. Will post onboard footage later.
I guess that is your phone number on the boom?
like, like and like! :D
- less weight; some panels will be lightened and lighter/thinner CF used.
- a dedicated sensor tray for optiflow, maxbotix and pxflow. Previously these were built into the battery tray.
- better CoG. I have extended the battery bay by 5cm rearward. Will now take "long" 6S nano-tech cells.
- longer and better ventilated ESC bays. Will now carry 8x 40A ESC's without issue. Will also make plugging in the cables easier, and an easier frame build.
- better mounts for PDB's (I've got a full gryphon stack in there right now) and GPS poles.
- gimbal mount "trenches" improved - will now take "square" gimbal mounts up to 8cm square.
WOW love the design! :D with a X8 design it should fly like a dream! Congrats! :D would love to have one!
For a v8 id recommend 4x4000 6S or 2x 6000, but you'd need to get 7x 4cm risers to deepen the battery bay for 4x4 (2x6 fits ok). Oh, and some gym work...it'll be *heavy* in that config!
Hey Euan, Nice work here! I think you have sold me on the air-frame :-) I'll cast my eyes on your blog tonight and see how you have gone with this (I see you have multiple iterations of this air-frame).
Thanks for sharing your build!
I love the chunky booms!