Eric Tweet's Posts (12)

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Hexa Fun

I've managed to get everything up and running again! This is my newish hexa from uDrones (I've decided to forgo a rant on that subject for now). After working around my PDB issue (still unsolved) and engaging in some close combat, things are looking good.

Recently I have been working on a research project involving autonomously acquiring imagery and data for GIS processing so I've been trying to put in as much time as possible before the snow starts flying. Over the past few weeks I've become significantly more confident in my flying abilities, as the video might infer, and I'm very happy with how the hexa flies with the APM2.5 and AC 2.8 (i've been just lazy enough to avoid upgrading to 2.8.1).

Thanks to everyone who puts so much time into developing all the parts and systems which make these amazing things possible!


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APM1 > APM2?


To avoid confusion, I ought to preface this post by mentioning that I began tests quite some time ago with the APM2 purple board. Since then I've gotten my hands on it's older brother the APM1 (hey, they're cheap now and then!). I have the APM2 in my heli now, so I decided to throw the APM1 on my quad in place of the APM2 to see how things compare...

So that might be a bit of an excessive title, but if I didn't know the differences between the two boards, I would claim that the APM1 is superior to the APM2!

A lofty claim, you might suppose, but let me explain why.

Firstly, the yaw issue I had with my APM2 is completely gone after installing the APM1. I'm using the same quad frame I had my APM2 on. Perhaps shuffling the ESC's around a bit helped. I moved them a bit farther away from the center and they now reside near the motors themselves. I've heard that to be a good thing, and I've heard it to be a negative thing having long + and - wires, so who knows.

The most surprising observation I made was with regard to loiter. This is the first time I've gotten anything to loiter. I can't claim to have even once gotten my APM2 to loiter, but right off the bat with default parameters, the APM1 on my quad loitered amazingly well (both using 2.5.5). Why? I have no idea. I didn't run a long test, but take a look at the results in the picture. The longest distance traveled was about 7 meters. There was a slight breeze. I suppose this warrants some careful comparisons of mounting, wiring, etc. for me in the future.

Anyway, that was my surprise for the day. I know the APM2 board is quite an improvement upon its predecessor, and I'm really not claiming otherwise. I suppose all I'm doing is pointing out the causes for my sudden onset of confusion and hope. Either way I'm happy. I have an APM1 in my plane, APM1 on my quad, and APM2 on my heli. No complaints here (except crashing the plane repeatedly, but that's another story...)


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T-Rex 600E with APM2 - Test Flight

As requested, here is a clip of one of my test flights with the APM2 on my 600. This may be the most boring video ever, but in this case, boring is exciting! The APM2 works amazingly well mounted on Align gel, where a tail gyro normally sits. Stabilization is very good using  these parameters, though I need to lower the yaw values since there's still just a bit of tail wagging.

I've had this bird for a couple years, so unfortunately I think there is a bit of play in the linkages, and a couple of the servos have sticky spots. This causes small variations in the rotor disc (leading to slight wandering) which the APM is not responsible for.

The previous stabilization system I had was a Robbe HeliCommand. Absolute rubbish. That caused more grief and wasted time than I can imagine. Although, I was terrified of tuning it and knew very little about the effects of vibrations, so maybe it was good and I didn't know it!

Either way, APM2 + TRex is awesome so far.


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The T-Rex Flies Again!


I didn't think I'd actually get this far so soon, but somehow I have. I got my APM2 strapped on to my T-Rex 600 and managed to get it in the air. In fact, I've even got it tuned moderately well!

I started out switching the APM from my 3DR quad to the trex frame and began the process of learning how to set up a heli. Being the overbearing fellow I am, I forgot to erase the eeprom so my initial setup was using quad parameters on a heli. After not getting it off the ground, I eventually erased and went through the setup process again and got things right. I got it in the air and tuned a few things and so far I'm happy with how it flies. I used auto-trim mode (ch 7 switch) to level it in the air and that seems to have worked quite well.

The APM board fits nicely in the typical tail gyro place right behind the main shaft. The board is mounted using the Align gel which I've had perfect results with on the quad, and lightweight velcro straps to gently hold it against the gel. No problems with vibrations whatsoever (that I can tell right now, anyway).

I'm happy to have this bird in my fleet once again, and with a second APM (1.0) board on the way I'll hopefully not have to switch back and forth.



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Beach Cruising!

After arriving in Nome, AK for the summer, I got the HK EPP FPV re-assembled and took it for a spin early in the morning (1:00 AM). With my APM 2.0 tied up with the heli right now, I'm still flying this thing manually (considering getting my hands on another APM). I have, however made a few modifications to the frame to make it more modular (for ease of transportation) and more efficient. I'll be posting those mods soon. For now, enjoy the waves!

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Flaperon Trial

With much excitement I found some time to give my dual setting flaperon system a test run. In the video, it's used during the low altitude and climb out at the beginning, the landing, and a couple other points along the way. It does feel a bit better for landings and launches, but I think I might increase the 'flap' angle to the full throw of the servo to get the maximum effect possible.

For those wondering, this uses the Turnigy 9x transmitter with er9x firmware. I have two switches which each supply additive signal to both of the differential aileron channels.

I'm moving in a couple days so I've packed up the plane and quad for now, and this'll be the last testing at this location for a while. I can't wait to see if ArduPlane can handle the tx-based flaperons (fingers crossed).

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A Break from the Quad - Fixed-Wing FPV!

In the spirit of finally getting around to things, I got the HobbyKing EPP FPV plane in the air, FPV style!

The video is of my 3rd FPV flight, so pardon the less-than-ideal flying skills. I've done a handfull of flights non-FPV, but quite frankly I'm rubbish at flying that way. I suppose that's to be expected since this is the first RC plane I've ever flown, so hopefully I'll improve in the future.

As mentioned, the frame is the HK EPP FPV. I haven't put the APM in it yet, since I don't really want to switch the board between the quad and this thing each time. I've made a few modifications, among which include better wing mounting and modularity. At some point I'll post some pictures of the setup.

My current goal is to add flaperon capability for easier landings and shorter runways, as well as better photography characteristics. Of course, I'll be diving into the ArduPlane stuff when I have some time...

Does anyone have any suggestions on where to start (PIDs, mounting location/method, etc) for adding the APM? Does the current code support flaperons in some manner (whether enabled in the code, or solely on the tx)?



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Higher and Faster

More good weather to test the FPV on my quad. I'm quite happy with the GoPro as both the recording and FPV camera. I just need to invest in a better mount with added roll stabilization. Also, as always the copter needs tuning. It has spontaneous wobbles that I need to figure out. I always dread the tuning process since some things seem to have no effect until they do. :P I have logs from the 4 flights I made in the video if anyone has some spare time and would like to look at them. Otherwise, enjoy.

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Some FPV with the 3DR - Testing the Quad


Finally managed to get everything together in reasonably working order. Lucky for me, the weather has been mostly perfect as well. The video is taken at about 9:30 pm, with plenty of sunlight to spare. Gotta love Alaska!

I figured the parking garage at the UAA campus would be a decent place to fly around. Not many people, no wind, good view - a good way to get some FPV experience. I'm not sure the seagull was too keen on the idea though...

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Quad, Mount, and FPV


After painfully waiting for the Alaskan spring time to do its thing, I've finally got my 3DR quad all set up and FPV-capable.

I managed to get some test runs in beginning in April to get the hang of flying a quad. It's been cold so I haven't done nearly as much as I'd have liked to. On the other hand, snow drifts make good places to bail. ;) Now that things are melting and warming up a bit, I've managed to find some time to add more junk to the frame. Here are the current specs:

3DR Quad Frame
RCTimer 880kv motors
RCTimer 40amp ESC's
12x4.5 Carbon/Nylon Blades
APM 2.0 (currently on 2.5.4)

Turnigy TH9x (with er9x firmware)
ChainLink Dare UHF Long-Range Tx/Rx (433MHz)
FatShark 2.4GHz video transmitter
GoPro HD Hero 2
Custom camera mount (temporary. whipped up in an afternoon)

I'm using the ChainLink since the only video tx I have is the FatShark 2.4Ghz. All of this seems to work quite well.


I have the GoPro plugged into the video tx so I can record and fly FPV at the same time via the same camera. The GoPro is sitting on a slab of Align gel which does a good job of killing the jello with 1080p@30fps. My APM2 Board is also on Align gel, held in place gently with velcro - just enough to keep it from un-seating from the gel but not enough to negate the vibration dampening.

I'm well-aware of the ghastly mess of wires protruding in all directions. This has very much been a dynamic build, adding and securing parts as I go along, seeing what fits best where. At some point I'm sure I'll put in the effort to neatly zip-tie all the wires where they ought to be and dump some aesthetic quality into the thing. For now, it works and does what I want.

The main goals now are to delve into the art of FPV flying and fiddle with PIDs to try to get the thing to fly solidly. Hopefully the refinement of loiter and the other auto modes will prove successful, since I've had poor luck with those to date.

Cheers, and happy flying!


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