AH-6Z "littlebird" scale FPV build.

[zeeflyboy]

So, There's one thing I dislike on scale helis, and that's when you can see the mechanics inside... completely ruins the illusion for me.

I've been doing some google image searching and popped up with the AH-6X... it has some nice looking doors covering the rear area which I think I'll replicate. The rub is that the opening there is really quite handy for getting screw drivers in and accessing equipment so I think the answer is to make working doors at the back there. Looks good in flight but can be opened for maintenance access.

This pic shows the doors quite nicely and also note the skid lights - this is the style I was going for when I modelled mine.




I'm also having a re-think about the secondary camera position... I think I may make an FLIR pod as in that pic. It leaves potential in future to make a moveable pod and of course fits the theme of having a "FLIR" a bit better. I think I'll modify that design slightly though.

[zeeflyboy]

had a bit of spare time this arvo and decided to get my hands dirty (and the floor). First I removed the moulded hinges and then covered the window from behind.... then painstakingly made a spacer to fill the window space before masking the whole lot off... in hindsight this was stoopid and I should have just gone with a sheet of thin plastic on the outside... live and learn and all that! There's always the other side to do!

Anyway here it is all masked off and ready to go:





And here after 5 layers of fibreglass.






This stuff is slooooooow curing so it will need 24 hours to finish. Bit of a pain but I find it much easier to work with as there's no rush before it sets up (about 45 mins) and goes on nice and smoothly. The quicker drying stuff tends to end up a bit more lumpy in my (limited) experience.


Once it's cured I'll give it a good sand/fill/sand/fill until smooth then lastly cut to shape.

[zeeflyboy]

So I got called from standby this morning only to then find out they had changed their mind and I had a few hours before they actually needed me so I came home and did some work on the door.... leaving it out in the sun yesterday appears to have worked since it's solid as a rock now.

Here's the piece removed from the heli after a bit of preliminary sanding (window marked out for alignment purposes).




I then drew in pen around the panel lines on the heli so I could see them through the fibreglass, traced them out on the fibreglass part and cut the part out leaving a couple mm spare around the edges. I then sanded the edges back using some sand paper on a wood block to make sure the edges were nice and straight... and ended up with this:





and here it is on the heli:




It'll need a slot cutting in the bottom (it'll look just like the AH-6X door when it's done) to allow the weapons arm out plus just some general finishing polish to get it perfect, and then I'll need to do some cutting on the fuselage of course.

[zeeflyboy]

Anyway, I've now finished the FLIR pod unit.

First we have the mount.... The cut out you see inside is for a 2x21x5mm bearing which should also give you a sense of scale.... the block is 30mm wide and the disc is 40mm diameter. This unit will be mounted into the front of the helicopter and fitted permanently with a bit of glass/epoxy.






Then we have the cradle... This as previously mentioned has a shelf that can accept a small servo which can then be attached to an arm on the FLIR pod axle and operate tilt. Another option is to mount a motor and a pulley system but I need to look into that a bit more... I've left enough space inside to be able to play a bit.

On the top we have the improved mounting axle which obviously gets inserted through the bearing in the above mount. Again an arm or wheel can be attached for a servo/motor operation. I've added a step which will press against the inner race of the bearing and so when tightened up it should be snug with very little play and hopefully no rubbing.








And last but not least the pod... just cleaned up a few bits and changed the axle to a straight design. I'll make end stops out of g10 as it gives me more control over tolerances and lets me play with arm length for the pod tilt.








The design is intended to allow the camera cable to run out of the pod through one of the axles and into the cradle, then the tilt servo and camera wire to run out from the cradle into the mount... from there it can get directly into the cockpit and be routed wherever needed. We'll see how all this fancy thinking actually works out when I get it printed.... fingers crossed! I'll be waiting to get my other pieces before deciding on material, and might do a few small tweaks to the design in the mean time.

[zeeflyboy]

just done a little work on the heli before I go to work this afternoon.

I hooked up my landing light - rather than use a resistor I went with a proper LED driver, it always supplies a constant 350ma to the LED and backs off it it gets too hot etc. All I can say is DAYUUUM this thing is bright... hard to capture in a photo but it's actually uncomfortable to look at directly even outside.

It's a 1W LED with heat sink and lens assembly.






Other than that I've been doing a bit more filling and sanding on the left door. Seems it wasn't quite as smooth as I had thought lol. Looks pretty good now but I won't be able to tell until I get a coat of primer on it - then I can do a bit more smoothing... I also cut out the hatch in the fuselage and the door for the weapons arm using a trusty dremel....

Slight change of plans here too - I decided to epoxy the door in place and have it fixed. It lends so much strength and rigidity to the side of the fuselage that I just thought it'd be stupid not to take advantage of it.





Other than that, I ordered some gel coat so that I can start to make the moulds for the clear windshield. Should be straight forward to make - just paint some gelcoat on the inside of the existing canopy pulls, add some fibreglass and then out should pop a nice plug for the vacuum forming machine that is yet to be built.

[zeeflyboy]

bit of fun today... I hooked up the controls in the seat.

[ame]http://www.youtube.com/watch?v=c_FY0Tb3lIM[/ame]

Using some tiny servos from HK... they seem great. Very light weight at around 2.5g each (manufacturer specs) but can run on up to 6v and are quite smooth... seem to have enough grunt for the application too with 0.17kg of torque.

Jobsa.

[zeeflyboy]

my screen arrived from adafruit yesterday and I just hooked it up for a test, without OSD for the moment as I don't have the time to hook it all up together...

It seems very nice - good clear screen and the image is good quality (much better than the video makes out in fact) and the screen is really very small form factor - there is very little size beyond the viewable portion.

It also powers on automatically which is just perfect. My only complaint is that they say the button on the back adjusts brightness - this is incorrect. It adjusts contrast - there is no brightness adjustment.

so, quickly tacked on some wires directly to the camera - this will be how I wire it up when I do it properly too, but I'll do a neater job and add some epoxy afterwards. This will be the best way to hook things up in the confined space of the camera pod. It also leaves the rear port free to plug in the OSD as required.





and the screen front and back, when installed I won't be using the connector of course - everything will just be directly soldered.







Video:

[ame=http://www.youtube.com/watch?v=Ut5J18K-6Bk#]AH-6 Dash sneaky peak[/ame]


and here is a initial draft of my video system wiring...

[zeeflyboy]

Just got back from work and picked up my package that I missed a few days ago from a neighbour - contains my skid lights and pan/tilt unit.

Here are a few quick excited pics lol. I'm so happy with how they have come out, I'm really chuffed so far! I forgot to order the flange bearings for the pan/tilt but nevermind - I'll go order them this evening. It actually looks to be pretty smooth without the bearings but I'm sure the bearings will prove useful in the longer term....


Image hosting now imgur by popular demand - please let me know it all works okay for you


















Still haven't committed to my FLIR pod, and may just do a few little design revisions now after seeing the material in question.

[zeeflyboy]

So, for those of you who don't get where I'm going with the pan/tilt hopefully this is clear!

Take one length of tube, and cut a slot to fit the servo...




Glue said servo to slot




and then assemble (please excuse the grubbiness! covered it in carbon dust....)



The best bit - the whole lot including linkages and servos weighs 15g! I'm quite chuffed with that.... The next big job is going to be hollowing out poor Juan to have his new carbon spine inserted. There will be a small bracket at the top near the "neck" to stop the whole thing wobbling.

[zeeflyboy]

So, today you can call me Dr Zee.... I would like to introduce you to Juan 2.0













You can see how the unit has been installed inside the body, I whipped up a quick fiberglass bracket just underneath the top section which holds the thing in place and stops it from wobbling back and forth or side to side. I know he looks scary, but don't worry he's 'armless.... (sorry... sorry... I do apologise).


[ame]http://www.youtube.com/watch?v=Myu7E3FoCEo[/ame]

[zeeflyboy]

couple of things today... first off, while I was fairly happy with the pan/tilt, after getting it in my hands I could see there were a few areas I could improve upon.

here's my v2









Improvements include tweaked camera mount dimensions and shape for a closer fit and smaller footprint, a brace for additional strength over the tilt tab with incorporated wire tidy to stop the plug from being pulled at during operation, a little beefing up with some fillets on the tab itself, and a little bling bling in the form of some personalisation... also a little improved clearance in some areas.


Aside from that, I decided to try out my plug making skills. A strange choice perhaps given that I haven't even made a vacuum forming machine yet, but I'm a complicated fellow. I thought it'd be wise to try first on the small section that yields the lower front sections.

So, first job was to buff up the interior of the stock canopy because it had a rough feeling, not smooth. This undoubtedly contributes to the lack of visibility with the stock canopy and after a good going over with some very light cutting compound (t-cut - an automotive scratch remover) it was looking much better. I then added several coats of meguiars NXT car wax to shine it up and help release the plug.

heres the part after my efforts. It's now much clearer to see through, but still tinted alas! This does give me the idea of buffing up anything I make from this plug though to improve clarity if required.



So I then painted the interior with tooling gelcoat and allowed it to turn tacky before applying a few layers of fiberglass. Left it overnight and then just now I broke it free from the mould.... this is how it popped out (used a bit too much resin, but never mind - it's not a structural part):






And this is it after a quick buff and wax... smooooooooth. Pretty chuffed with that - should be a good basis for starting to play with making a good clear canopy.

[zeeflyboy]

I did some final design tweaks to the FLIR pod and now finally ordered them... grand total for the FLIR pod unit to be printed and sent - almost exactly 100 euros. Yikes... hope I didn't screw up the design!

Since last time you've seen them, on the cradle I've added support for 10x15x3mm flange bearings for the pod tilt axis, changed the servo mount, changed the positioning tabs and a few other small tweaks.




On the mount I've added the control horn (also doubles as retainer) and a replacement landing light surround since I will have to remove the original one.




And finally on the pod I've changed the mount post/tab arrangement slightly, and added a standoff for the bearing.




Ordered these in white flexible and strong polished, since they will be painted to match the heli anyway... looking forward to seeing if my creation will work and how it'll look. My main worry is that it'll look too big on the front. If that is the case knowing me I'll probably go with a smaller camera and re-design a smaller pod/cradle. At least smaller is cheaper here lol.

Aaaaand I just fitted some of my nice new shiney bling bling...

KDE gyro mount at the rear which is where I will mount my SK720/Naza-H/whatever. The plastic mount was really crap and flimsy here so thought this would be a wise update.




KDE Thrusted bearing blocks and adjustable motor mount. The thought of around 7 Kg of helicopter hanging off a radial bearing with axial load just makes me cringe, so I got these thrusted blocks instead. They combine a radial and a thrusted in each block (only really need the bottom one since this heli will never be doing inverted manoeuvres, but hey, I had to buy the pair anyway lol. The adjustable motor mount makes fitting my oversized motor a bit easier.






I am also going to be converting it to direct to swash for the servos.... this gives more precise control with less slop and drag from linkages, and reduces weight. Also helps with fuselage clearance.

[zeeflyboy]

What do you guys think about this? I whipped it up today... not exactly directly related to the project but a side project if you will. The idea is that you can attach this unit to an empty module case and it will correctly position the EZUHF for a vertical antenna. By using an empty module case it means you can have the EZUHF directly plugged in to the radio rather than by the USB port, and also means that the mount would probably work for most modules (I designed it for my futaba).

The alternative is to build the whole module in too, thus removing the need for a spare case but not sure if it's worth the hassle.

edit - link http://www.shapeways.com/model/74540...af6f8e9d6d3bd6

in a nice IMRC red








anyone got any bright ideas for additions before I order it?

EDIT - oh and while I was at it, I made this little button to cover the hole left if you pull out the old telescopic antenna... Shimples. http://www.shapeways.com/model/74543...ust-cover.html

[zeeflyboy]

And another creation for today - an IMRC 5.8Ghz v2 enclosure designed to fit a 20x20mm 5v fan.... the idea is that in my setup since the vTX's aren't powering the cameras the 5v supply from the IMRC vTX will supply it's own fan... looks like they draw around 0.2A at this size - can anyone remember off hand what the max draw on the 5v rail of the vTX is?

Since the vTX's are going to be enclosed in the fuselage I thought active cooling would be a good idea, plus I always find them a bit of a pain to mount... this enclosure aims to solve both of those issues. Cut out at the front gives access to the cable release latches without disassembly.

http://www.shapeways.com/model/74561...fe56b9b7e258fb

[zeeflyboy]

So, not much to report but I'm afraid to say I've been busy on the computer again! If you've had enough of 3D designs for now then skip this post... sorry! Normal service will resume soon after I've run out of things I need to design and they all start arriving!

I was looking today at building the upper dash module and I decided I would almost certainly get a better result through my new found love of 3D printing...

I have designed a full dash module, it has a small cut out at the top under the glare shield which the dash facia panel can slot into. For access to install screens and for maintenance I have incorporated a removable panel into the back, and I added mounts for the 3mm leds that will illuminate the static displays (one per display). I'm quite proud of this puppy - it took a long time for me to figure out how to make it!





http://www.shapeways.com/model/75247...e589639621?li=



I also designed a collective stick to mount to my servo arm, and a cover to tidy it all up. Because I need access to the arm screw for installation, I have made a separate cover that will then conceal the hole once installed.





http://www.shapeways.com/model/75128...e752496b3688a8



And finally, I designed myself some rudder pedals. The design is such that the pedals can rotate on the arm, thus getting rid of any problems with the feet not staying attached as the angle changes (the pedals themselves will be permanently attached to the feet). The rudder pedal arms fit inside the mount and are then free to pivot back and forth. The whole lot is then mounted to the fibreglass panel you can see installed in the picture - I made these today out of 1mm fibreglass sheet. The linkages from the servo will then run underneath the flooring panel and attach to the bottom of each arm. The whole floor will also then be covered in scale metallic style flooring.

[zeeflyboy]

Back to my roots for this post - Backyard shed style bodge-it-engineering.

So, Looking at my pilot, the legs don't go far enough up for the rudder to work properly because they hit a mechanical stop at 90 degrees. So poor Juan's suffering isn't yet over, I mercilessly hacked off his legs.





I then used some epoxy putty to shape shoulders and add hinges to his legs that will allow the legs to move up a little with the rudder. The right shoulder has embedded wire which will effectively form the arm controlling the cyclic stick. I needed more degrees of freedom here than a simple hinge could provide so I've gone for a flexible wire instead. the left shoulder has a flat edge and will then have an arm attached which will be free to rotate fore/aft only. Combined with an elbow joint this will then allow the arm to move nicely in line with the collective stick.





Next up I need to shape some foam segments to replace the missing leg and arm sections... should keep things nice and light.


edit - the right arm is almost done... just need to drill and attach the hand. The foam in between the segments helps stop the sleeve material from collapsing inwards when the joints move... I've done a quick test and the arm can reach all 4 points of the cyclic stick extremes, but is also the right length to fit inside the sleeve which is good!

You can also see the small 3mm carbon shaft in the left shoulder which will act as the pivot point for the left arm and allow it to rotate backwards with the collective stick.

[zeeflyboy]

A slight geographical snafu has occurred....

I have some leave coming up at the start on november and will be in the UK, and when I ordered my FLIR pod the ship-by date shapeways gave put it firmly during my time in the UK. Accordingly I got it sent to one of my UK addresses.

Shapeways however completed it well before the target date and sent it on thursday.... so I'm currently separated from my creation by about 700 miles.

Girlfriend to the rescue however! she has taken some pics for me to share with you - apparently It all fits and locks together well, the eagle eyed may notice the pod is slightly loose in the cradle - this is due to the bearings not being installed. I have to say it looks to have come out exceptionally well, I'll reserve judgement until I've been able to examine it myself but looks like my love for shapeways is on the up and up.

The only reservation I have is that the thing might be a bit humongous, if so I'll have to consider redesigning a new one for a smaller camera... we'll see how that goes when I can actually install it in the heli.


All parts separate (FLIR pod, cradle, mount, retaining/control arm and replacement landing light surround)





liiike a glove





Pod fits

[zeeflyboy]

couple of detail shots to show the quality... I'm pretty impressed with this for their basic material!

[zeeflyboy]

some good news and some not so good news...

Here's a few pics of my pod going together, works quite nicely (no servos yet to try making it move) but I think it's too big. It really dominates the front of the heli (though the picture exaggerates it somewhat due to the perspective.
















Anyway, I'm nothing if not prepared and here's my contingency plan - a significantly smaller pod and cradle based on the 25x25mm cam here (original cam is 38x38 for an idea of size difference) http://www.securitycamera2000.com/pr...amera-FPV.html

While I was at it I decided to make a small change - the front panel of the pod is now quickly removable to adjust focus, change lens or access the camera. I added holes at the top and bottom for two tiny (1x2mm) neodynium magnets to hold the front cover in place.

[zeeflyboy]

Bit of hacking with a dremel and this is where I'm at:











It's already firmly mounted with epoxy but next up I'm going to reinforce the area with some extra fibreglass, including wrapping it just inside the mount to increase the rigidity of the whole section and well and truly lock the mount in place, then tidy up around the edges and make sure it's all nicely blended in. You can see the bottom where I had to deal with the old landing light location too, it's now patched and I just need to fill it up and smooth it out.

However I just picked up Halo 4 and I have some alien butt to kick...