Bell 222 550 size project

[Keyrigger]

I like that colour. Will there be accenting stripes or bands?

Don

[npomeroy]

Originally Posted by Keyrigger

I like that colour. Will there be accenting stripes or bands?

Don

Yep - see post #48 for a sample of the gold striping.
It will be based on the graphics of ZS-HMS
http://www.airliners.net/photo/Bell-...658a429c1b5bd2

[Keyrigger]

Brilliant. Nice, simple scheme.

Don

[npomeroy]

It's been a while, but I've been slowly picking away at the build.

Here are images of the aluminium and CF attachments for holding the BEC and SK Power Bus (on CF at the sides) and the sK720 on the horizontal platform. The hunk of wood is for ballast to approximate to the fuselage weight for flight testing. The circular hole in the ply is to provide clearance below the motor. Images not ready yet but I have attached most of the electronics etc and am doing the calibrations and setup.

[Keyrigger]

That's looking really nice. I am really curious to see how you manage the batteries when it is at the point of setting the mechanics and the batteries in.

Don

[npomeroy]

Originally Posted by Keyrigger

That's looking really nice. I am really curious to see how you manage the batteries when it is at the point of setting the mechanics and the batteries in.

Don

Yeah, so am I!
From my moments measurements calculations, especially with the heavy CC ICE100 right forward inside the nose, I should be able to place the 5000mAh 6S lipo a few cm rear of the instrument panel, placed transversely. It means any cockpit detail will stop at a false floor at about the pilot's hip level. I'm hoping I can insert the lipo into that position (i.e. under the cockpit floor) through the top opening. One advantage of the Atom500 mechanics is the frame is quite small and gives more room to work around.
We will see. It will be a while yet as I need to complete the mechanics test bed and tune it for flying.

[yf222000]

What brand of paint are you using? It looks really good.

[npomeroy]

Originally Posted by yf222000

What brand of paint are you using? It looks really good.

Thanks. Actually it is the "cheapest and nastiest" paint - I would need to ask the brand but I understand it is nitrate lacquer - it is made up by a local automotive paint supplier. (I understand this may now be illegal in USA). How it looks is not the paint but the application. A feature of these lacquers is that (a) they flash dry VERY quickly so minimal waiting between coats; (b) each coat tends to dissolve into the coat below it which means you don't need to sand to key in between coats. But light sanding or buffing of course gives a smoother finish; (c) the finish is satin not gloss. To get a gloss you need to polish the final coat after curing. But buffing metallic is really tricky so I'm leaving mine with the satin texture, although I may apply automotive wax as additional UV protection. When I applied wax to a small area it did not increase the gloss.

EDIT: Please see "there are no secrets" book at http://www.harryhigley.com/Books3.htm as a really helpful understanding of model finishing.

[yf222000]

Thanks for the info. The paint on your model looks very nice.

[Reefmonster]

Following your build as I have just started on the Painted version. I am interested to know if you did all the work to the retracts with the retract frame still in the Fuse? Yours is looking great and I am wanting to do a copy of your retract system. I already have the retracts but am trying to figure out how in the world you did the mods still in the fuse.

[npomeroy]

Originally Posted by Reefmonster

Following your build as I have just started on the Painted version. I am interested to know if you did all the work to the retracts with the retract frame still in the Fuse? Yours is looking great and I am wanting to do a copy of your retract system. I already have the retracts but am trying to figure out how in the world you did the mods still in the fuse.

The short answer is "carefully". Posts 36 and 46 show the main points, but I'm happy to provide any additional details here or by PM. I do have a pair of 10-inch surgical tweezers that I often use manipulating small parts. Of course all the work on the actual wheel struts was done outside the fuse with the black retract units removed. With the pre-painted version you need to be more careful of blemishing the paint work of course.

[Reefmonster]

Yes, I can definately see the need for some long reach tools

[npomeroy]

I use a Dremel tool and I have the long reach flexi attachment. I use the dremel for grinding away plywood etc., but I can't remember what I needed to use to cut away internal ply parts. I did use clothes pegs and alligator clips to hold the aluminium brackets in position for test fitting, and later when gluing.

[npomeroy]

Some more images. The mesh is fine stainless steel that I happened to have. Most readily available metal meshes are too coarse in my opinion for a good scale appearance. The strobe is the side-shining one from here http://tomsha.com/shop/product_info....e1525894c24648
The LED is glued to a copper strip as a heat sink (it is 1 Watt), and the ply part is to anchor the leads, which otherwise easily break off at the solder lug.

[npomeroy]

@ Reefmonster: The servo ball links and the bellcrank were all pre-attached to the aluminium bracket before the whole assembly was glued in place.

[npomeroy]

Did a couple of short flights today. It seemed stable and controllable for a while and then lost power. HS seemed to fade and extra pitch was needed to keep it in the air. So I landed promptly. I checked the battery voltage including individual cells and seemed good, so I cautiously tried again and it clearly lost power quite quickly. I was thinking I might have too small a pinion and the CC governor might be forced to 100% output. So I downloaded the Castle files and the RPM was showing holding constant, and power output never went over 90%. The only cause would seem to be the pinion slipping (the ESC governor only "knows" the motor rpm). Indeed on dismantling so I could get at it the pinion can be turned by hand relative to the shaft! I've never had a problem before but as this is a very high torque motor. So I will flatten the shaft and try again.

[npomeroy]

I fixed the slipping pinion - all OK. But the SK720 was logging a vibration (level 3 - 5) at the motor frequency. I re-balanced it by aluminium tape outside the can and now the vibes are down to 0.25. Flies quite well and only draws about 18 amps in gentle flight. Motor and ESC stay cool.

I finished the control panel today. It is simplified from the "real" one, with some imaginative license. Only after viewing the photos I see some instruments are the wrong way up. The panel chassis is thin card spray painted grey, with holes punched. Clear sheet is stuck behind. Then I used clear epoxy in small dots on the back side to pick up the individual paper instrument images.
I may include white LEDs behind the panel for backlighting - not sure yet, but have shown a backlit image.

[npomeroy]

I've put on the gold striping.

[rdavis]

Looks amazing!

[yf222000]

Wow! Looks very nice.