Test #2 report – we made it!

As per our yesterday’s article, all has been prepared and star constellations were favourable so I grabbed boys (Sebi, Jacob and Oli) to the shore to repeat our previous test – get our jet-cart to the Blue park and back (nearly 2km ride).

Map with our trip below.

Weather was much better than through our first trial – as you can see we’ve got 11km/h (3 knots) cross-wind to tackle.

I took evidence of our test by taking a picture of Jacob’s watch – it was 8:10 am morning when we started.

And we have a lift off! 🙂

I took multiple videos of Sebi steering the cart on the pavement, but it’s tilt in combination with that cross wind was giving him a hard time.

And at the end we made it – I took a video when reaching the Blue park!

By that time there were already few defects:

• Front-right gimbal lost as its axle broke due too much stress and material fatigue

• Rear-right gimbal lost as propeller lost its all blades – no idea how that happened, very likely some of its dislocation

• Finally we’ve lost left vector-thruster – due to a loose screw

Interestingly, even after loosing 2 gimbals and one vector – Sebi’s been able to keep steering it all the way back! I think it was a coincidence of a cross-wind coming from a starboard and actually absence of those gimbals on the right side, but Sebi did one of the longest stretches there. I think it was more than 200m, while I’ve been able to take a shot of its shorter half.

And that’s it! We’ve discussed the outcome with Sebi and he was much more pleased than with our first test. Clearly the problem was that gimbals’ orientation was unison and he couldn’t use those in some more convenient way. Also covering all that distance and making it back – so satisfying.

Another big win was the battery – real hero of our test. Our battery made it all the way there and back and still remained sort of 60% full (min 17.4V, max is 25.1V).

There were clearly few lessons learned:

1. We need a pre-launch checklist to be able to prevent some of those problems we encountered like that loosen screw on a vector:
   – check all screws on vectors
   – check all screws on gimbals
   – check that batteries are properly attached and not loose
   – check that all batteries are fully charged (Main, Arduino, Servos, Remote)
2. Commence a dry-run on all features
   – Remote connects
   – Both front motors turn and in a proper direction (which generates thrust)
   – Both vector-thrusters operate
   – All 4 gimbals are responsive and can move in all directions obeying commands from remote
   – All 4 gimbals motors can are responsive and rotate in a proper direction (which generates thrust)
3. We need to carry some minimal tools with us:
   – Thin pliers
   – Phillips screwdrivew
   – Duct-tape
   – Scissors
   – Multi-meter
   – Replacement batteries (Main, Arduino, Servos, Remote)
   – Gimbal wrench
4. Replacement parts to be stocked up:
   – Have a spare propellers at least each clockwise and counter-clocwise
   – Have a spare gimbal (2)
   – Have a spare servo (2)
   – Have a spare motor (1 main and 1 gimbal each)
   – Have a spare intake
   – Have a spare vectoring thrust
5. Design changes
   – Make gimbal axles more robust
   – Make gimbal gearbox serviceable
   – Make axle-fork joint more robust (currently just glued, but probably not enough surface there)

Well, just that re-design of gimbals and stocking up on those spares will take us couple weeks. But I am sure it is worth it and while it looks like a chunk of work, it is much easier now when that initial design is already in place. So let’s get back to work!

I hope you had some fun, as always please let me know your comments / ideas, it is always awesome to get some feedback from all of you. Meanwhile, stay tuned! 🙂