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Mocha maiden flight 
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Joined: Tue Jun 21, 2011 7:34 pm
Posts: 116
Post Re: Mocha maiden flight
Rocketguy, sorry to hear that you had an unfortunate experience on your maiden flight.
You raise some valid concerns, so I am hoping this post clears some of the confusion up.

The Mode 1 flight behavior can be found here and a discussion on the switch from helicopter controls to airplane controls can be found here in the Mocha User Manual.
I am not certain which discussion you mean when you say
but the referred discussion about that behavior doesn't exist
so I would appreciate your letting us know if there is a broken link or something else so we can fix it.

As a novice at RC planes, I personally like not having to think about the roll/yaw coordinate transformations myself when flying, and prefer to have the on-board controller take care of it. In general, we have found (based on feedback from people who have flown the quadshot) that novices find it easier to deal with mode 1 because they do not think about the transformations themselves. Experienced pilots, on the other hand, are practiced at thinking about these transformations, and so sometimes find it difficult to adjust to the computer doing it for them. Similarly, in mode 2, the quadshot coordinates turns for you, i.e., you do not need to feed in rudder; rudder is automatically fed in when you bank the vehicle. This is also something experienced pilots are accustomed to doing themselves, sometimes leading to unexpected aircraft behavior. As BrettG mentioned, if you are an aircraft pilot, mode 3 is probably the most familiar to you. It is possible to hover the Quadshot in this mode, but it does not have the hands-off-return-to-vertical behavior. In general, for mode 1, it is best to think of roll, pitch and yaw in ground fixed coordinates. If you push the roll stick, the vehicle will roll relative to the ground (i,e, its lift vector will tilt relative to the ground, regardless of whether that lift is being provided by the rotors or the wing), not about the axis passing through its nose. Similarly, if you yaw, the vehicle will yaw about an axis perpendicular to the ground plane, not necessarily what we would call yaw in the traditional airplane sense.

Re requests for firmware with fixed coordinates, rather than an automatically changing one, this is something that we are working on, and will release as a software update that users can flash onto their vehicles if they choose to do so. We will have an approximate release timeline after the remaining Mochas are shipped out.

Re actuation authority concerns, please note that the second 3-position switch (on the right side) on the transmitter is a sensitivity control. Please flip to a more sensitive setting (up = more sensitive) on the switch for greater authority. A description of the sensitivity settings can be found here. If the actuator authority seems limited only in helicopter yaw, please check that the elevons are deflecting in the correct direction for the commanded turn. If they are not, i.e., the deflection is in the opposite direction, it is possible that they have been plugged into each-other's outputs on the Lisa/Lia. In this case, they will fight the differential torque of the motors, limiting helicopter yaw authority. If this happens on your vehicle, the fix is to swap the outputs that the servos are connected to on the Lisa/Lia. The servo wires can be identified on the Lisa/Lia since they have Red, White and Black wires and have standard servo connector housings on them. The motor controllers on the other hand, have brown, orange and red wires.

Hope this helps.

Thu Sep 27, 2012 7:35 am

Joined: Tue Aug 28, 2012 3:57 am
Posts: 4
Post Re: Mocha maiden flight
First off, I'm a complete RC novice and everything I say below should be taken with that knowledge in hand.

Had my first flight with the mocha at 11am today in a park in San Francisco. I had no problem holding a hover and doing some basic maneuvering in mode 1, but quickly got overconfident then lost control on a second round of flights. On reviewing the video, I think I might have bumped something out of alignment after one skitter across the ground. Immediately after taking off after that the plane went away from me quickly and I never regained control. I should have recognized that the plane was behaving differently than my earlier hover and adjusted whatever was loose.

In trying to recover I took it higher than I wanted and got turned around. I was practicing in a wide open spot in a park near my house, and after I drifted over the tennis court I attempted to come back. I think I'd gotten reversed with the top and bottom of the plane (hadn't spent enough time thinking about it while I was hovering) and accidentally "corrected" it into the side of a building. Around a dozen kids who'd been watching in awe raced to the crash site and there was much gleeful poking. My 19 month old son had bonded with the plane and was in tears when it broke, but the crash looked worse than it was. Seeing how upset he was ended up being the worst part.

Damage is all repairable. One glued winglet popped off, all 4 pylons snapped off cleanly. one propeller snapped in half, one is damaged. The worst seems to be a small tear in the elevator seam and a slight break and bend in the wing near the winglet. I'll attempt to steam the wing straight and see if there's any sort of tape that works well to close the elevator tear. I saw the note about gorilla glue, which I have.

I think I'd like to get a simulator working. I saw there was some discussion on the subject in other threads so I'll go through there and see if I can find a safer and easier way to get more practice with the controls (and RC in general) before I wreck the plane again.

Anyway, I really enjoyed it as it flew, and look forward to repairing it and getting better. Thanks for making such a cool device.


Sat Nov 03, 2012 9:51 pm
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