AH-6Z Littlebird Night-Ops build project

[hase2]

I don't think it's overkill. Small doesn't mean budget imo.

[Zeeflyboy]

Okay so big thumbs up to Rob Lefebvre (an Arducopter developer).

I was chatting to him re pixhawk/arducopter and he pointed out the tail issue I was seeing could be magnetometer related. He suggested I try rotating the helicopter and seeing if the drift reversed.

It hadn't occurred to me that the Ace would be using mag in manual mode, I had assumed it was only something that would be used in auto modes.

Anyway, I did his test and while the drift didn't reverse, it did change in speed. I re-ran a compass calibration in the apartment and then tested again. Drift was markedly reduced and in some orientations the tail servo finally fell completely silent and all drift stopped.

So, looks like the tail issue is most likely just the magnetic environment of my apartment. Teaches me to make assumptions about how the system works too.

So, that looks like one problem down (knock on wood!), I now just have two more glaring issues to address - tail vibration and the head imbalance.

The tail should be a simple matter of some time spent... I will remove one tail shaft and balance a single pair, then add the second shaft and tweak until the whole thing is smooth.

The head I can't figure out. Something must have been damaged in the crash (and it's not the main shaft, I've tried 3 new shafts) but I can't see any obvious issues. Vibration level is totally unacceptable though.

Sooooo.... I have made contact with the company that makes this super premium 5 blade head on their 5 axis CNC. It is insanely expensive, I was quoted €539.50... When I asked if that included the swash he said no, lol. That's mental. However, luckily I am mental so have ordered it - if this doesn't spin as smooth as silk it'll be going right back to Germany lol.

So, things will resume in due time.

In the mean time, check out how my little micro quad has turned out so far, I'm pretty chuffed with that!

[krikey]

That is one great looking quad copter. I see you've used CF for the rods and plates. What parts are 3D printed?

[unharmed]

The red bits?  :D

This whole thread has just blown me away. Amazing.

[Zeeflyboy]

yeah, red bits are printed... rest is cut on the CNC

So good neeeews

I had to get a new swash, the old one I had intended to use caused the head to bind as the balls were too close together, and I didn't like the PSG adaptor as it raises the swash balls above the axis of rotation which is ney good design. So ordered a new swash with spacing similar to the PSG adaptor. It arrived today and I fitted it all together, just span it up and BOOOM - smooth as a ken doll's smooth bits.

So two problems now struck off the list... next for attention is the tail.

[Rudeboy]

Dude your skills know no bounds, super impressed mate!!

love the mini quad too, if you need a beta tester I just so happen to have all the parts needed to put it in the air, would be with CC3D though not vector ;-)

[Zeeflyboy]

thanks matey, but not really true! they definitely know some bounds....


Re the micro quad, we had a good laugh with it at the IMRC lab yesterday but anthony managed to break a motor mount where it attaches to the landing gear leg. Had a good idea to replace the CF leg with stiff rubber and it should eliminate the weak point... other than that it stood up to several tumbles with no damage so pretty happy.

video here:

First test - ZQ-M Vortex



and back to the AH-6:

sooooo.... This tail was giving me a headache.

The problem is that due to the floating shaft design it is extremely difficult to get the shaft precisely centred and I think this is what was leading to the majority of my vibrations.

I thought about my problem for a bit and came up with this solution. I printed out a tail locking block... I measured the distance between grips (20.2mm) and printed out a block with 20.3mm width that could slip over the tail hub and spindle, with a hole to allow me to then insert and tighten the retaining grub screw. the end result is hopefully a better balanced tail!

first do the front




And then flip it round and do the back. Note the hole to allow the grub screw to be inserted/tightened - nearly forgot that lol.





end result looks promising:

[Zeeflyboy]

spool up check - the vibrations are a lot better now.

Of course there's always going to be vibes with the big gears, big motor, torque tube, tail gears etc etc but it's now about as smooth as any heli I've had... Need to check with tail blades later but they should be pretty good - if not I may need to look into dynamically balancing the tail with the blades in place.

AH-6 Mechanics vibration check

[Zeeflyboy]

So, not the most exciting of posts but one I am posting just for completeness - can't leave the mundane stuff out! The Scorpion motor was not new and something I had been meaning to do was change out the bearings for some new ones. While I was at it I decided an upgrade to ceramic hybrids was in order, and it also means I can pretty much leave them maintenance free for a long time until changing them out for some new ones... very convenient for a scale body. (they also spin more freely and up to higher rpm, so in theory they produce less drag in the system freeing up power/efficiency).

Motor pulled apart (just a case of removing the cir-clip and spacer) and next to the new ceramic bearings that will be installed:




I decided to do things properly for once rather than my normal way, and got the proper Scorpion bearing removal tool... glad I did as it makes this process a piece of cake. First up attach the collar to the motor mounting holes and insert the bearing puller... tighten up the screw in the end which expands the shaft and wedges into the inner race of the top bearing, then proceed to wind it out.






Then you just insert the small bearing pusher tool and push the bottom bearing out




next just push the new bearings in, using the supplied tools and make sure they are firmly seated...







et voila, better than new!





I'm glad I did do this as the top bearing was actually quite rough and had some slop, if the bearing fails it can take the whole motor out so it's worth making sure everything is in tip top condition. Might have dodged a hidden danger there! Found a great price for these bearings on alibaba and the quality appears to be very high indeed - I'm tempted to fit out the whole helicopter with them tbh!

[Zeeflyboy]

I have managed to find a chap that can help me out with something I have wanted for a long time - a real working primary flight display with Artificial horizon, Speed tape and altimeter.

The way he's doing it is with an arduino board using an imu and gps, this sends the info to an intelligent display which then turns it into the graphical representation. The screens however are either too big or too small for the dash so I have had to downsize slightly to a 1.5" screen and that necessitates a re-design of the dash panel.


So I had a bit of time to start re-designing the dash, Im going with a different modular approach this time.

Previously I designed the whole dash as a single printed piece, this time I'm going to design the flat section and cut it out on the CNC machine. The inserts will then be designed separately and printed individually, then assembled together after painting.

This should make it cheaper, easier to change in future if i ever want to swap things around and also make it easier to paint.

so here is the start of the dash (still several cut outs to do) which will be cut on the CNC.




and here it is with the assembled pieces so far:



I decided to make an entire panel dedicated to LED warnings/info, so now you have (from left to right) missile LED, Minigun LED, Mode selected (Manual, Atti, Gps Atti) with red/yellow/green leds, and on the right surrounded by hazard lines the Emergency backup led which indicates a BEC failure and activation of the backup power.




on top of that it will have the functional working AHI on the right screen and perhaps a navigational display or similar on the left.

[stevec]

Have you seen the minnaza OSD project?  Sounds like it would work here too.  Takes inputs from the naza and uses a minim OSD to interpret the signals and display the results.  Would be easy to hack it to light leds on the panel...

Looks great by the way.
/Steve

Sent from my C6603 using Tapatalk

[Zeeflyboy]

I'm not using the naza, not sure if it would work with the ace one?

I don't need that anyway tbh - the only led input from the controller that I require on the dash is the mode selector and that is easily achieved with a DElight controller that listens in on the mode channel and is programmed to switch a given led at each switch position.

cheers for the thought though!

[Zeeflyboy]

so here is a rough idea of what the new dash will look like with a splash of colour...





and just out of interest this is the rear view of the dash panel which I will cut on the CNC this time. Just need to decide what material to cut it from!

[Zeeflyboy]

so here's a little mockup of the dash - should look something like that except hopefully a bit better with some detailing and weathering etc




and a check at the back to make sure the screens will play nice

[ClippedWing]

Beautiful work Zee!