AH-6Z Littlebird Night-Ops build project

[Zeeflyboy]

So, momentus occasion... take 2 worked much better lol. Big thanks to FPVflyer for the fix on the problem I was having.

I got 4 flights in today, didn't do any tuning at all because it was too cold to sit around tweaking things... as such you can see there's some bobble that I can hopefully tune out and the tail gain needs a little adjusting, but the wind was quite gusty so it was not really conducive to fine tuning anyway - I just wanted to get out and fly it regardless!

So, quick summary and thoughts of the flight:

- take off in manual
- fly a little in manual mode then switch to GPS mode.
- on first engagement it drifted to the right then stopped, subsequent engagements of GPS mode didn't drift much at all.
- Altitude holding and position holding was incredible considering the wind, really impressed. Once I fine tune the gains and get it looking a little smoother it'll be seriously cool.
- In GPS mode it was like flying a co-axial, so easy. It was as though it took care of all the flying and you just basically point it where you want it to go... very impressive again considering the conditions and lack of setup.
- In manual mode this thing shifts... for what is about 6-7kg of helicopter up there with the additional weights I was really impressed by just how you could throw it around a bit. Lots and lots of power.

Downloaded the flight log data and she's pulling between 17-24 amps during general flight with an average around 20-21 or so... a little higher than I'd hoped to be honest, but I have yet to experiment with different head speeds. All this was done with a flat 90% throttle, so would be interesting to try say 80% and a governor for example.

So anyway with a 12S 4000mah that would be just over 9 minutes to 80% depletion... not too bad and if I can stretch that out to over 10 minutes with some fine tuning of the headspeed I'll consider that very good for the weight of the heli.

Enough talk, here's the video... Enjoy and let me know what you think. Quite a feeling to see something you've spent so long creating take to the air, can't imagine what it'll be like when the whole thing gets airborne for the first time!

it's available in 720p so full screen it and crank up the volume to hear the heli sing.

AH-6Z mechanics test flight

[g.collins]

well played that man, I bet that felt great getting it in to the air. well don bud.
;) G

[FPVSteve]

Thats super impressive - excellent, I can't wait to see it all up and running properly.

[Zeeflyboy]

Cheers guys, I'm really pretty chuffed so far... I'm a happy bunny this evening lol.

It'll be interesting to fine tune the headspeed, gains etc on a calmer day and see how well I can get it flying... I think it's extremely promising.

I was most impressed by how easy it is to fly in GPS mode even with cold shaking fingers. This will be absolutely brilliant for easing myself into the FPV based flying of the heli and getting used to flying from the cockpit in particular... then as I get more familiar with the heli I can start pushing in manual modes for more adventurous flying.

[Ratty]

Awesome, that looks great, very well done.

You sure are one brave guy. My maiden on my helis is mainly just hovering and hoping nothing flys off. You didnt hang about.

Cant wait to see this finished. Keep up the great work.  ;D

[dogzilla]

I imagine a lot more FPV heli's will be seen now that the Naza-H is out. I bloody want one now.

[Zeeflyboy]

Ratty - fine line between brave and stupid.... Very fine lol.

Yeah I think the system has a lot of promise. Not withstanding my initial problem the 4 flights today went very well with no tweaking of settings at all. I am quite confident that when I've done several test flights with changes to settings it'll be a top notch flying system.

When they finally add the promised semi auto take off and landing it'll be the FPV heli system of choice I'm sure. As it is it works fine of course, you can auto hover, take off goggles and land manually... Or try landing in manual mode via FPV and hope to god you don't touch the tail... But once the update is done you'll be able to easily complete the whole flight from start to finish in FPV mode.

I'm fairly impressed thus far....

[FPVSteve]

I wonder how many helis (and how much ££££££) DJI go through testing their hardware - they must surely use simulators but the, reality is reality...

[Zeeflyboy]

Good question...

I imagine they are pretty clued up now, they have a lot of experience in the advanced rotorcraft flight control system arena. That said, the system for sure will have bugs and its interesting to think how many Helis got destroyed in the name of progress lol.

So far I'm impressed - we'll see if that feeling continues once I've tried to tune it!

[wgt40w]

Congratulations - an Apache is 'born' - well it is currently in the nude !

Bet Juan and Julio are out on the town tonight !

[Zeeflyboy]

Apache?

Ain't no stinkin Apache!

Lol... the AH part of the designation (same goes for the Apache AH-64 or the Cobra AH-1) is simply "Attack Helicopter".

[wgt40w]

Apache?

Ain't no stinkin Apache!

Lol... the AH part of the designation (same goes for the Apache AH-64 or the Cobra AH-1) is simply "Attack Helicopter".

Think you already knew - wgt40w - "he know nuthing"

[Zeeflyboy]

If its any consolation on another forum I just got a guy complaining that I should have built a civilian heli rather than authorising and exalting (no, really, his words) The more deplorable aspects of American imperialism and the atrocities they commit.

You know more than him... You know it's a model helicopter, not a real life machine of American oppression.

[FPVSteve]

:laugh:

[Zeeflyboy]

So, just popped out for a quick test flight despite the constant drizzle today... thought it would be a good chance to test the GPS functionality under poor conditions.

I dropped autopilot gains down to 80% (from standard 100%) but left altitude gain as is at 100% since it worked very well last time, and I also just dropped the tail gain down to 40% HH. I added 6% left Atti trim since the heli wants to drift right quite significantly when atti mode is engaged, and I upped GPS Atti/Atti agility up to 130% to make it more responsive.

I also dropped the headspeed down to 80% (ungoverned for now).

Notes from today:

- Even in cloudy and wet conditions, Naza achieved 6+ satellite lock (no red lights) within around 40 seconds.

- Much smoother in Autopilot modes, no nodding around and tail doesn't bounce, although the latter is still not quite perfect.

- Bit more drifting about in GPS Atti today, although still very impressive and stays within a tight area. Could either be the cloud cover and rain or the fact I reduced AP gains... next time will try 85%. Still drifts right in vanilla Atti mode, more left atti trim needed.

- 80% throttle seems to be significantly quieter than 90% and amp pull is down to an average of what looks to be around 19 amps.... 6.5 minute flight burned 1850mah, which is around 285mah/min. That translates to roughly 11.5 minute flight time to 80% with 4000mah packs, still has enough power to fly effortlessly. Looking promising! I was planning on trying 70% on the second flight but I decided to stop as the rain was picking up.

- At 80% tail authority was lacking, in heavy climbs the tail didn't have enough authority and would slowly turn nose left... This surprised me in all honesty since with 4 x 95mm blades I expected it to have plenty. This might be due to the fact that with the tail on the left as per the real heli, the the blades are coming down into the downdraft... I had expected with 4 blades I would have had authority in abundance but perhaps due to the weight and low head speed things aren't working like I'm used to. Two options - flip the tail back to the other side an accept that it isn't true to scale, or buy spin semi symmetrical tail blades to increase lift generation at low speed.

- I tried flying around with a bit more "gusto" in GPS Atti and it actually moves out pretty well for a scale bird. It seems to have a "speed limit" in GPS atti, if you push the stick forwards all the way it'll nose down quite nicely initially to around 45 degrees but then as you approach max speed it will start to level out and hold the required attitude for that speed.... that combined with the fact that the Naza will hold the altitude for you while you whizz around, removing the need to add collective pitch to maintain height, makes for quite a weird flying experience! It's good though - flying it is really quite effortless in these modes and it makes scale flying very easy indeed.


So, program for the next test flights:

- Increase AP gains to 85%
- Enable governor mode on ESC
- Hook up RPM sensor to elogger

In other news, I missed delivery of my new 5 blade head yesterday while at work... post came 10 minutes after I left (doh!). Will pick it up tomorrow morning from post office.