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Boeing Vertol BV234 Chinook G-BISP


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The delivery van driver has been. Woohoo!

 

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RS Components has been really fast. Unfortunately I've had to contact them. I'm pretty sure it's an accident so I'm not in any way annoyed or upset - I'd just like the bearing. One of the red and white packages for the ball bearings hasn't been heat sealed along the bottom and the bearing has gone walkies. It was all very well packaged otherwise and the wee bearing isn't in there so I'd imagine it fell out before the packaging staff even pulled a handfull of them out of the storage bin/box/whatever they use to fulfil the order. They hardly weigh anything so it would be an easy miss.

 

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Anyway, keen to try things, the first lesson is one of tolerance. The 3mm stainless steel rod I bought from eBay isn't. My calipers aren't the best quality and under-read by about 0.1mm so I think this is actually 1/8th inch diameter, not 3mm as advertised.

 

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I have an idea on that which I'll test later. It may involve power tools and abrasives...

 

Meanwhile, the other components are not quite 3mm bore either, but in the other direction.

 

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That's maybe not the end of the world, as whilst the bearings and gears currently don't fit on the steel rod, if I can make them fit then a bit of an interference fit would be helpful actually. Reaming out plastic gears is easy. Reaming out the inner bore of a ball bearing not so much - so it's the shaft that needs to go on a diet.

 

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Those calipers are not the very best choice do measure an inner diameter (esp. in that range), but using an electric drill and sandpaper is the shot from the hip that will come to any modeller's mind first ("I have an idea on that which I'll test later. It may involve power tools and abrasives...").

 

I assume the plastic gears are supposed to stay on the shaft via a press fit (and the plastic used does not stick to any glue), but a little Loctite 638 will help in case the shaft gets too thin for the metal ball bearings.

Edited by Jochen Barett
typo
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53 minutes ago, Jochen Barett said:

Those calipers are not the very best choice do measure an inner diameter (esp. in that range), but using an electric drill and sandpaper is the shot from the hip that will come to any modeller's mind first ("I have an idea on that which I'll test later. It may involve power tools and abrasives...").

 

I assume the plastic gears are supposed to stay on the shaft via a press fit (and the plastic used does not stick to any glue), but a little Loctite 638 will help in case the shaft gets too thin for the metal ball bearings.

 

I upgraded even from that, suspecting myself of lacking the patience. I have tested a piece of the steel rod with a power drill and a combination belt sander & grinding wheel bench tool. It seems to work although getting uniformity will be difficult. Now I know it basically works though, I will cut the pieces to length and work on the individually. The plastic bearings have some elasticity. The steel ball bearings are not very compliant though. The shafts will probably end up slightly cigar-shaped with the ends tapered more than the middle, but that's ok so long as everything fits on where it's supposed to.

 

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One feature worth mentioning, and which I'm glad I thought about in advance is this pair of spur gears.

 

The smaller 12 tooth gear has a 4mm (apparently) bore which should (haha) match the 4mm shaft on the 300rpm geared motor which is on its way from eBayland. It's going to drive a 3mm shaft though - the green one - and whilst 3mm gears are available and it's tempting to look at the tooth count, it's actually the tooth size and overall diameter which matters. A 16 tooth gear which has a diameter that gives me the speed reduction I need and teeth of suitable size to mesh properly with the 12 tooth 4mm gear has a 5mm bore.

 

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Fortunately, I didn't order a smaller 16 tooth 3mm gear which just wouldn't have fitted the gear on the motor, but I did get these little bronze bushes which push into the 5mm bore on the gear and make it 3mm instead. Or someone's idea of 3mm anyway. This is quite snug when pushed all together but I'll loctite it in due course anyway to prevent any foul-ups.

 

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2 hours ago, Jamie @ Sovereign Hobbies said:

 

I have an idea on that which I'll test later. It may involve power tools and abrasives...

 

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27 minutes ago, Jamie @ Sovereign Hobbies said:

+++ - and whilst 3mm gears are available and it's tempting to look at the tooth count, it's actually the tooth size and overall diameter which matters. A 16 tooth gear which has a diameter that gives me the speed reduction I need and teeth of suitable size to mesh properly with the 12 tooth 4mm gear has a 5mm bore. +++

 

Size does matter. If you were fluent in German, you'd have to read this one https://de.wikipedia.org/wiki/Modul_(Zahnrad)

English speakers get away with the short passage on module or modulus found here https://en.wikipedia.org/wiki/Gear#General .

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I measured the shafts on the Adobe Illustrator scale diagram, and marked up the steel accordingly with tape, knowing that pen marks seem to vanish instantly that a cutting tool is brought on-scene.

 

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And the pieces are mocked up thus. I have made a mistake in ordering lengths 200mm long in my enthusiasm to get started, but the big green shaft is actually 247mm long so I've had to order a longer length. You can get the idea from this though. Where bearings and gears aren't on the shafts, that's because the shafts need more time in the gym.

 

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The tip of the pen shows where the electric motor goes. A "pen drive" if you will? I'll see myself out...

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14 hours ago, Jamie @ Sovereign Hobbies said:

A "pen drive" if you will? I'll see myself out...

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Close it on the way please, must keep these types out, don'tcha know.

 

Now listen up lad, if you are doing this sort of stuff you need a micrometer.

 

Calipers can be useful but not if you already know they have problems.

 

I can probably find a redundant Imperial one if it'll help.

 

 

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Crikey this looks interesting   great job so far in all the figuring out, it's all way above what my small brain can handle!!!🤪 Hope it all works out  as will be phenomenal to see the rotors turning together.

Chris

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1 hour ago, perdu said:

Close it on the way please, must keep these types out, don'tcha know.

 

Now listen up lad, if you are doing this sort of stuff you need a micrometer.

 

Calipers can be useful but not if you already know they have problems.

 

I can probably find a redundant Imperial one if it'll help.

 

 

 

Thanks Bill, I realise calipers aren't ideal for this but they're probably more accurate than my powersanding efforts! :D

 

In all seriousness though, I would not object at all to an Imperial set - I am bilingual with measurements, having grown up with radio controlled models built to plans mostly drawn by older generations in Imperial sizes. With balsa and ply as well as hardware being sold in either or units depending on the whims of the manufacturer, one had to learn very quickly to hop between systems to make any progress!

 

In the meantime, behold here a layout. The long shaft is still too short, but it shows more clearly how it's going to look.

 

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One of the cuts comes close to the removeable panel with the round window on the HC1, a feature not present at all on the BV234, so to improve my chances here I took the opportunity to glue in the heavily relief-detailed panel and window, sanded off the relief which stood proud of the fuselage skin then filled over it to take care of that which sits lower. No real need to be especially tidy at this point as there is much more butchery to come and surface work with it. I may even fill all the panel lines on this, as they are somewhat trench-like and that's not obvious on photographs of the BV234. Lap joints and domed rivets, yes, but big 1990s fashion panel lines not so much.
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  • 2 weeks later...

This weekend and last I've mostly done other things.

 

I have tonight cut out the port side fuselage, hence this model kit is now committed to become a civvie Chinook or die.

 

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I've set up the Cricut Maker with 30thou plasticard and the big blade ready to cut, but Cricut Design Space - the awful software one must talk to the machine via - needs to update, at something closer to dialup internet speeds.

 

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And since I'm uploading them all to Photobucket for a different forum right now, and this is what I'm going to do instead since, as above, Computer Says "No", this is what I'm working on out in the shed :)

 

A dinghy!


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I'm working on internals now. Here having a rest on what's going to be the top of a 125 litre water ballast tank.

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This sticky mess was assembled earlier today. Once all this epoxy has cured, it will be cleaned up, trimmed round the edges and glued in to the bottom of the boat. It's the mast step, so will see some pretty big loads.

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2 hours ago, Jochen Barett said:

How many 14ml pots are you calculating for the dinghy?

And will it be "Admiralty Disruptive Pattern" or something else?

 

1 hour ago, psdavidson said:

Are you calling her "Dignity"? Shame you're on the wrong coast.

 

/P

 

Hi Folks, thanks for looking in :) I may actually use one of my colours for the boat. I would like to paint most of the hull an epoxy white, but the rubbing strips upwards I'd like to paint a dark grey like Admiralty Pattern 507A. I'll have my mast and spars in varnished wood. It would look something like this, which I drew as a logo for the Facebook and Instagram pages I use to keep the boat pictures public and sort of separate from my personal life.

 

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Meanwhile, the Cricut software update finished and I set it to cutting the first new Chinook fuselage piece which took about an hour or so, whilst I generated some more premium quality sawdust cutting the false keel and skeg for the boat from a big iroko board and thickness planing them down to the correct, er, thickness.

 

Despite all the time, the cutter hasn't quite punched out the windows but it doesn't need too much persuasion to run round the back with a scalpel.

 

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I think I'll use this thicker bit for strength, then I'll laminate in a very thin sheet of clear, and finally I'll cut another same as this but from 10thou plasticard to laminate on the outside.

 

 

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34 minutes ago, Jamie @ Sovereign Hobbies said:

I think I'll use this thicker bit for strength, then I'll laminate in a very thin sheet of clear, and finally I'll cut another same as this but from 10thou plasticard to laminate on the outside.

That should look good. How are you getting on with the gears?

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23 minutes ago, Back in the Saddle said:

That should look good. How are you getting on with the gears?

 

Hi,

 

I haven't done anything else with those since the last post, other than follow up with RS Components who have dispatched a replacement for the missing ball bearing.

 

Realising that I could appear very rude, I've exchanged some private messages back and forth with Bill (perdu) about the micrometers so it seems sensible to hold fire on the shafts for a bit. Now you mention it, the 300mm long steel rods never showed up. Hmm...

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1 hour ago, Jamie @ Sovereign Hobbies said:

I think I'll use this thicker bit for strength, then I'll laminate in a very thin sheet of clear, and finally I'll cut another same as this but from 10thou plasticard to laminate on the outside.

 

Or... could you just use thick clear polystyrene sheet to begin with, mask the windows, and forget all about the laminating?    I always find that it's next to impossible to get a nice flat surface when laminating large areas.

 

 

 

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8 hours ago, Jamie @ Sovereign Hobbies said:

I've set up the Cricut Maker with 30thou plasticard and the big blade ready to cut, but Cricut Design Space - the awful software one must talk to the machine via - needs to update, at something closer to dialup internet speeds.

I use Inkscape to draw along with a 3rd-party extension that provides an "export" function to directly drive my Silhouette Portrait. I checked that extension but it only supports Silhouette devices. :( Some quick Google-foo suggests you can import an SVG file into Cricut Design Space. Inkscape directly produces SVG files so you could use it for the design and then relegate Cricut Design Space to driving the cutter. Inkscape is quite good; it's useful far beyond the cutter. I also design decals in Inkscape and directly print them on a printer or cut masks on my Silhouette depending on my needs. To be sure, Inkscape is Yet Another Skillset, But you may prefer it over the Cricut SW.

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Another voice raised in favour of Inkscape, steep learning curve for an old fool like me but well worthwhile

 

My only concern with it is its refusal to operate my scanner as an input device

 

(Posting the next couple of days James, both imperial)

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On 5/29/2022 at 9:20 PM, hendie said:

 

Or... could you just use thick clear polystyrene sheet to begin with, mask the windows, and forget all about the laminating?    I always find that it's next to impossible to get a nice flat surface when laminating large areas.

 

 

 

 

Really? I've had reasonable success with it. I would prefer to avoid clear sides if I can, since masking is quite vulnerable overall and alignment of multiple sets of masks will be absolutely critical. Laminating works best if it can be done under a little pressure. I can make the laminations separate from the fuselage anyhow, so infinite tries are possible :D

 

On 5/30/2022 at 1:57 AM, dnl42 said:

I use Inkscape to draw along with a 3rd-party extension that provides an "export" function to directly drive my Silhouette Portrait. I checked that extension but it only supports Silhouette devices. :( Some quick Google-foo suggests you can import an SVG file into Cricut Design Space. Inkscape directly produces SVG files so you could use it for the design and then relegate Cricut Design Space to driving the cutter. Inkscape is quite good; it's useful far beyond the cutter. I also design decals in Inkscape and directly print them on a printer or cut masks on my Silhouette depending on my needs. To be sure, Inkscape is Yet Another Skillset, But you may prefer it over the Cricut SW.

 

On 5/30/2022 at 9:17 AM, perdu said:

Another voice raised in favour of Inkscape, steep learning curve for an old fool like me but well worthwhile

 

My only concern with it is its refusal to operate my scanner as an input device

 

(Posting the next couple of days James, both imperial)

 

Hi, good call on Inkscape but I've probably miscommunicated here. I avoid Cricut Design Space as far as I possibly can. I do the same as you do, albeit in Adobe Illustrator since we have an Adobe license through the little business. Like so:

 

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The process is essentially the same though:

1) Do all the important work in different software (Inkscape, Illustrator)

2) Save artwork as .svg file

3) Import .svg file to cutting machine's crappy software

4) Use whichever tool is necessary in cutting machine crappy software to Attach/Group your .svg artwork's separate vector paths to prevent Cricut Design Space from helpfully dismantling all your carefully laid out paths to cut them as separate pieces of sparkly multi-coloured cardboard and JUST CUT IT THE WAY I DREW IT DAMN YOU!

5) Press Go button on machine :D 

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