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hendie

Wessex HC2 Crab Cabs Pt II (Fly Wessex - why on earth did I?)

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It would look even better bolted to the back of another flying Wessex! :pilot:

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Ah, a 3D printer eh? Given the number of parts you're sending to Shapeways there must be a 'business case' to invest and set up 'Hendie AM Inc' :wicked:

The one 'my friend' has works remotely and notifies his phone when the printing's finished so he works while it's earning him money. Just sayin' :) 

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43 minutes ago, CedB said:

Just sayin' :) 

 

your card is marked sonny boy!   mark my words

 

 

 

 

 

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So where were we then ?   Ah, 3D printer and all that.  Well, no point in keeping you lot in suspense

 

Here are the results of my first print in the new printer.  There were a few issues to sort out first, mainly to do with the slicing software and not the printer itself.  Once I had a file I was happy with, it was off to the printer and everything ran fine - even although I was taking a wild guess at the settings.

 

On the left we have the kit parts. Quality is fine but they got several shapes wrong and when you know what you are looking at, the kit parts just don't work.  On the right is the part I had printed at Shapeways some weeks back. Nice sharp detail and it looks like a Wessex rotor head.

In the middle we have my very first attempt at DIY 3D printing. Overall, I am very impressed with the print.  All the detail is there no not quite as sharp as the Shapeways version - however, as this was my first print I chose to go safe with the settings and I also printed it (relatively) quickly.  I believe I can get finer, and sharper detail, but for a first print -color me happy.

The print quality even on those settings is at least the equivalent of an injection molded part.  More experiments to come.

 

PA250004.jpg

 

Staying with the rotor head, I realized that I still had a few additions to ehhrrr, add before I was finished.  The first one that jumped out at me were the droop stops.  Can't have a rotor head without droop stops can we?

Resting on my digit in a sort of grey plastic is Fly's offering.  Sorry, that's not going to cut it here I'm afraid - which is why you can see the beginnings of a new droop stop just to the side of it.  Some styrene, two different diameters of brass rod, and some fine stainless steel wire wound around the center rod for a spring.

 

PA250005.jpg

 

Proof of concept.  Not perfect but looks way better than the kit offering.

 

PA260007.jpg

 

So off we go on a mass production run...  I used the internal jaws on my calipers pressed into the styrene to give me exact locations for drilling - they made a nice little indent, though I still managed to stray off on a few ocasions.

 

PA260008.jpg

 

Bits of wire added. - I used a small rat tail file to create the curves either side of the spring post - again not perfect but it does capture some of the look of the 1:1 part

 

PA260009.jpg

 

Add some more styrene, stainless "springs" - put 'em together and what have you got ?   4 droop stops

 

PA260010.jpg

 

Then fitted in place. I forgot to mention - I did use the kit PE parts for the spring arms (the dayglo parts) which you can just see here.

 

PA260011.jpg

 

But we're not finished yet are we ? Oh no - we still have the rotating scissor link to add.  I scratched that by stealing a bit of rotor head from the 1/72 Wessex, some styrene rod, and a piece of Trumpeter plastic left over from my Dauphin build

 

PA270018.jpg

 

Sorry for the poor photo here - but I also added some 1.0 mm Meng nuts and bolts  (and adjustment arms added from brass rod)

 

PA270023.jpg

 

Then glued it in place

 

PA270024.jpg

 

and painted 'er all up.  I believe we have a decent rendition of a Wessex rotor head folks, or at least one I am happy enough with to use on the kit.

 

PA270025.jpg

 

And on the very day that I first fired up my 3D printer, some stuff from Shapeways arrived.  Had I known I was actually going to buy one, I may have held off and tried printing these myself. Hey ho.

WHat we have here folks is a mixture of train parts and Wessex parts.  I'll leave it to you to figure it out.

 

PA270019.jpg

 

One of the reasons I sent that order in was because of the trouble I was having trying to make the pitch linkage bracket for the tail rotor blades.   On the left is a kit part - PE, and a right PITA to try and put together and surprise surprise, it doesn't look like the real part.  In the center is a part I tried making myself from styrene - I gave up at this point when I saw that I just couldn't make it small enough - or tidy enough - which was why I decided to have it printed - the one on the right.  I know it's difficult to tell what it looks like from this photo, but bear with me.

 

PA270021.jpg

 

Cleaned up and stuck on a rotor blade, it starts to look really good.

 

PA270022.jpg

 

Then looks even better after paint. - As do the other tail rotor parts.

 

PA270026.jpg

 

The big question is - will it all stay together and will they ping off into the ether ?  Or a more likely scenario - will they break when I start to assemble everything ?

Those 3 "prongs" on the bracket are only 0.3mm thick, and I think I have a 0.4 mm gap between them - and I have to fit 2, yes two rods into each one. 

Daft old me only ordered the exact quantity I need - no spares!   I could have slapped myself - at least now I may be able to print some of my own if I need to

 

until next time

 

 

 

 

 

 

 

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On 22/10/2019 at 00:26, hendie said:

your card is marked sonny boy!   mark my words

Am I forgiven now? Just a little bit? :D 

I’m sure this is just the start of ‘Hendie 3D Inc’ - are you going to post your experiments for the crowd? Please?

 

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1 minute ago, CedB said:

Am I forgiven now? Just a little bit? :D 

 

I'll consider it.

 

Okay, considered.

 

Your off the hook for now Ced but watch yer step!

 

 

2 minutes ago, CedB said:

are you going to post your experiments for the crowd? Please?

 

I certainly can if folks think it'll be interesting enough.  Should I do it in this thread? or maybe start another just for that ?

Actually I have some more things to print - I just need to create the models first, so I might have something ready for printing by next weekend - stay tuned

 

 

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I for one would like a ‘hendie tutorial’ thread if you have time :) 

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Me too, me too sir

Please sir me too

 

And I would like to see how those finer settings you mention can do the job

 

This is exciting use of technology in our hobby

 

Exciting times, not just 'interesting'

 

👌👌👌

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15 hours ago, hendie said:

Daft old me......

Aah, so your name is actually Hector! Please say 'allo to Zaza and Kiki for me!

 

Those new additions are fantastic, I love the droop stops. Not being a rotary type chap I assume they simply stop the blades from drooping too far when they are stationary, hence the name? 

 

Ian

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7 hours ago, limeypilot said:

Aah, so your name is actually Hector! Please say 'allo to Zaza and Kiki for me!

 

you just caused a series of rather bizarre flashbacks there Ian.

 

 

7 hours ago, limeypilot said:

Not being a rotary type chap I assume they simply stop the blades from drooping too far when they are stationary, hence the name? 

 

Pretty close Ian - the droop stops prevent the blades from lowering too much when blade RPM is low.  @Ex-FAAWAFU can chime in here as I'm sure he's much more au fait with the little blighters. 

Only when centrifugal force is high enough do the droop stops extend, thus allowing full travel of the blades up and down.

Having one stick and fail to return was rare but did happen ocasionally.  Part of our "bring 'em in" routine was to watch the rotor head and make sure the droop stops had engaged (i.e. you couldn't see them any more) before informing the pilot he could shut down and apply the rotor brake.

In those instances, the recommended "fix" was for the liney to clamber up on to the trans deck (with rotors still turning) and swing a BFM  (big... mallet) at the offending droop stop each time it whizzed around in the faint hope that you could knock it back in again.  (that could have been a complete fairy tale, but how else would you get them back in ?)

I never had to carry out that procedure though on occasion, I did have to climb up onto the trans deck with the rotors turning - not for the faint hearted.  Even less would I want to swing a big heavy thing into that mass of metal snakes whirling around at a gazzillion RPM)  - I like having both arms

 

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5 minutes ago, perdu said:

eek!

 

Indeed. Can you imagine the  look on an elf n safety bloke's face at someone doing that these days....??!!

 

Absolutely incredible rotor head gizmos there hendie, brilliant miniature engineering!

 

Keith

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I only ever flew in a Wessex as a loafing LH seat passenger, but droop stops certainly occasionally stuck on Sea Kings.  The brightly painted weights are to allow the Chockhead (“Liney”, I believe the Crabs call them) to see whether the stops are in as the rotor RPM decreased (& out as it increased - they could stick in either position).  
 

Their purpose is as Hendie described - without them the blades might easily strike the deck / ground (Google ‘helicopter blade sail’ and you’ll see a striking photo of an S-61 with blades in all sorts of places they shouldn’t be).  At high RPM the blades are kept relatively rigid by both centrifugal and aerodynamic effects, but blades also need to be able to flap up & down in flight.  The droop stops are removed as rpm increase and the centrifugal force overcomes the force of the spring; and inserted as rpm decays and the spring ‘wins’.

 

For a fuller explanation, look in my Sea King build (“ZE419, a Sea King that temporarily forgot how to fly”).

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I Never cease to be impressed by your mastery of realistically detailed modelling Hendie

 

CJP

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A little bit more of an update this evening folks.  dagdnabbit, why does this forum auto-post whenever I scroll ???  They need to fix that. Pronto

 

Lost my train of thought now I have.   Tail Rotor, yes, tail rotor.  I had a few parts arrive from Shapeways last week and quickly threw a coat of green paint on them, and now it's time to start playing with them to see if they actually work (or not!).  If you remember, I had nothing to go on but a few Fly parts that were completely incorrect, so I may well find out that what I have made is over, or under-sized.  I guess I'll find out soon enough.

As seems usual these days, we'll start with drilling ridiculously small holes in ridiculously small parts that I can hardly even hold.  This is part of the linkage assembly of the tail rotor, it probably has a name but I can't remember what it is. The shininess is due to the superglue I slabbered on the inside of the part to try and give it some strength - these printed parts are very fragile, especially when you go really thin walled.

 

PA280001.jpg

 

Then I had an idea... there was a faint chance I could string all these parts together using fine stainless steel wire. So more teensy little holes drilled and wire superglued into the holes.

 

PA280002.jpg

 

Then I could use these wires as attachments to the rotor frame, like so.  But just before we go there, lets take a moment to recall what Fly offered in the kit - this little misshapen thing with half a hook hanging off to one side. 

 

PA190006.jpg

 

Compare that to the 4 appendages surrounding the frame thingy here.  Now you know why I got those parts printed.    How do you make that up above look like these below?

 

PA280003.jpg

 

Handling this was heart pounding - 4 little spiders all wanting to wriggle around and escape while I was trying to position things to see what on earth I was doing, all the while trying desperately not to break it, or pull their little legs off.

 

PA280005.jpg

 

Unbelievably, I had yet another idea - I always find that superglued wires inserted into holes tend to pull out quite easily, so I thought if I added a little washer on the back face I could slabber yet more superglue in an attempt to keep the wire in place. 

 

PA290006.jpg

 

Pretty much like this folks.

 

PA290007.jpg

 

The grey matter must have had an adrenalin rush or something because that little washer idea fostered yet another idea concerning yet another little washer. 

After I passed the wire through the hole in the frame thingy, I could slip on another washer at the back end, and then superglue the wire behind the washer before trimming the wire to length.  What did that mean ?  Well, it meant that those little wriggly spiders are now glued into place and believe it or not, they are still free to rotate !!!

One done, three more to do.

 

PA290008.jpg

 

I figured I needed that freedom of movement because I have no idea what orientation these things will end up in, and I harbor no doubts whatsoever that I am going to have to rotate them in order to get the pitch linkages glued in place.

Not looking too shabby at all, and without going back and checking my references (can't at this moment due to a broken laptop), they don't look too far out of scale

 

PA290009.jpg

 

another shot, different angle,  just for the sake of it.

 

PA290012.jpg

 

OOoohhhhhhhh - really starting to look complicated now isn't it ?  Just like a helicopter should.

 

PA290010.jpg

 

Of course, once the rotor blades are on you can hardly see anything at all.  Par for the course.

 

PA290011.jpg

 

In among the stuff that arrived this week was a bunch of resin rivets that allowed me to finish off the riveting on the tail section.  This could almost be getting close to paint!

(*edit* then I spotted that bracket below the mesh with another bunch of holes that need riveted) 'doh!  My excuse is that my thumb was covering that every time I looked at it.

 

PA290013.jpg

 

All those rotor parts are firmly shut in a box so that I don't lose them and will only be fitted at the last moment as the whole thing is so fragile.  It's an accident waiting to happen if I try and fix it now.

Also included in the stuff box was this little gem... perhaps a clue as to a future build ?

 

PA290014.jpg

 

 

And that's all folks.  I'm going to try and get back on my train build as soon as a new side frame arrives which I am hoping will be this weekend

 

 

 

 

 

 

 

 

Edited by hendie

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Don’t do it Hendie! Biplanes are the work of Satan and all of his little helpers! 👿

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3 hours ago, Bandsaw Steve said:

Don’t do it Hendie! Biplanes are the work of Satan and all of his little helpers! 👿

Well I for one can’t wait to watch Hendie weave his magic on a Brisfit.

 

Aw

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3 hours ago, Bandsaw Steve said:

Don’t do it Hendie! Biplanes are the work of Satan and all of his little helpers! 👿

Is true.

 

Mind you, so is that tail rotor gear

 

Wikked!

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Superb hendie - and it goes round too! Brilliant :) 

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Ooh, a proper aeroplane coming up!

Are we there yet? Are we? Are we?

 

Ian

Edited by limeypilot

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19 hours ago, hendie said:

it probably has a name but I can't remember what it is.

Was it the pitch change spider or star?

Whichever, it's epic. Micro modelling!

 

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19 hours ago, Bandsaw Steve said:

Don’t do it Hendie! Biplanes are the work of Satan and all of his little helpers!

 

I believe you Steve but sadly, in a moment of weakness I decided to build one of each type of a/c that 28 Sqn flew, and guess what ?  Yup, you got it.

 

15 hours ago, Andwil said:

Well I for one can’t wait to watch Hendie weave his magic on a Brisfit.

 

7 hours ago, limeypilot said:

Ooh, a proper aeroplane coming up!

 

I make no promises about timing though there's reasonable chance it should be this century at least.

 

 

15 hours ago, perdu said:

Wikked!

 

12 hours ago, CedB said:

Superb hendie - and it goes round too! Brilliant

 

15 hours ago, Ex-FAAWAFU said:

That tail rotor is superb.  Great work!

 

5 hours ago, Pete in Lincs said:

Whichever, it's epic. Micro modelling!

 

Thanks guys. It just gets worse from here.

 

 

5 hours ago, Pete in Lincs said:

Was it the pitch change spider or star?

 

Wasn't the star on the front end ? It could be the pitch change spider.

 

 

Having time to think is exceedingly dangerous.  Having a 3d printer is even more dangerous.

After making that last post, I got to thinking.... if I am modeling this in a blade folded condition, and with the tail folded, shouldn't it follow that the tail should have a gust lock applied ? That thought spurned another thought - it shouldn't be too difficult to make a gust lock, BUT, yes there's always a but!  If a gust lock is fitted, all the blades would be pulled forward.  The kit hub is molded so the blades are on on the same plane.  I guess I need to make a new blade hub.

I won't go into how another thought jumped into the action proposing that in theory, I could design a blade hub with a little clearance inside each of the individual mountings, and when printed, the blades would actually be free to flap back and forth.  I'm definitely not going to tell you about that part 'cos I know what you lot are like.

 

 

 

 

 

 

 

 

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How cool would it be to have Hendie live next door to you, every night would be a masterclass in modelling, although I think both wife's ( and maybe even Hendie) may have something to say about it :giggle:

 

Riveting stuff here( no pun intended).

 

As for the mysteries of 3D printing, your guidance and thoughts would be priceless for many of us......more work, I know!

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