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Westland Wasp HAS 1: 'Ambuscade Flight: XT778'


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Good afternoon gang and hoping this finds you taking your ease.

 

 I was considering a virtuous walk earlier, but a combination of rising NW winds  and the Atlantic Ocean in sublimated form: 

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- put that off for a while and I headed into the studio for a bit more hub activity instead.

 

Speaking of which...

On 24/12/2022 at 06:28, mark.au said:

“But that is not the question. What are we doing here, that is the question. And we are blessed in this, that we happen to know the answer. Yes, in the immense confusion one thing alone is clear. We are waiting for Godot to come the main rotor head -- ” 
― Samuel Beckett, Waiting for Godot (mostly)

😁

I've only ever seen the play once, in London in the late 80s, and still have the programme:

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If I recall, the helicopter maintenance sequence was a bold innovation that divided the critics...

On 24/12/2022 at 08:07, Pete in Lincs said:

I was thinking Scott Bakula in Quantum leap

Who I immediately got confused with Scott Baio, star of that dramatic masterpiece: Joanie Love Chachi.... 🤮

On 24/12/2022 at 08:07, Pete in Lincs said:

The voice has more or less come back.

Picturing you recovered... 😁

 

https://youtu.be/AuV3ohoEM6Q

 

On 24/12/2022 at 08:55, giemme said:

Happy Holidays to you too!

 

On 24/12/2022 at 13:49, Brandy said:

Merry Christmas to you and yours Tony!

 

Thanks Giorgio & Ian, hope you're both getting a chance to relax.

On 24/12/2022 at 09:00, perdu said:

note to self:

 

Fire up Fusion again and this time try harder

If it's a ny consolation Bill that's me every time I start up Fusion! 🤖

 

In discovering that robot I also discovered a 🍠 sweet potato emoji in the forum software and...just...what possible modelling circumstance warrants use of it? :laugh:

On 24/12/2022 at 13:49, hendie said:

(one of my favorite films btw)

Mine too Alan! Fond memories of it turning upon on those late-night horror double-bills BBC2 used to run on Saturday nights in the late 70s.

 

One of my greatest cinematic thrills would be to rock up to a drive-in movie theatre somewhere in Nevada that had a triple-bill of Them!, It Came From Outer Space, and The Thing From  Another World running continuosuly throughout the night.. All made within three years of each other and still superb.

On 24/12/2022 at 13:49, hendie said:

Happy Crimbo to you and yours Tony

You too mucker. Socks 'n all. 🤝

On 24/12/2022 at 20:51, Spookytooth said:

Fascinating stuff this 3d lark, but I can see the way forward with it.

Isn't it Simon.? I like to think of it as just another strand in an ongoing process, which makes you think: Gawd knows what the next one will be after this! :laugh:

On 25/12/2022 at 07:57, AdrianMF said:

Have a smashing Christmas break.

You too Adrian.!🤝

On 25/12/2022 at 07:57, AdrianMF said:

Oh and @hendie, what’s the film?

It's from that old Ealing Studios comedy: 'Highland Midges Galore!'

 

A revisitation with fresh eyes had me back modifying the first iteration of the  dag link/rotor hinge assembly, as there was even more going on structurally than previously interpreted:

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Essentially I pulled everything back on the timeline to the original blank for the hinge and then redrafted the subsequent designs and profiles leading outward from it. One of several reasons for this is the presence of a diagonal 'snubber strut' (effectively a shock absorber running at right-angles betwen the flapping links) - which you can see displayed in this rather fine angle of a Scout rotor head here:

spacer.png

Image credit: Vertical Flight Society

Reasoning that this feature was at 45° to the rotor axis but needing to be aure my designs were coherent, I temporarily duped the parts around the vertical transmission axis and mocked up a snubber to test the hypothesis:

52586342302_56973196df_b.jpg

Those angles all look pretty good to me from above - 

and below, the blanks to fill in are plain to see ⤵️

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Next time out I can hop back a few places on the timeline in order to block in all the missing features between the existing sides of the flapping/drag link assembly, and then complete the snubber and bases for the rotors before joining the whole assembly together as one (though with hub and hinges separate parts of course).

 

My mind has - unsurprisingly - been exercised recently with how I'm actually going (be able) to display the rotors on the finished the model.

 

As this is a visual replica rather than a fully-articulated engineering model, I face the same problem of any modeller in any material in terms of how far it is feasible to go down the parth of articulating various parts. In terms of having the main rotors posable between fully open and folded back into the (is it Forth or Severn bridge in slang?) clamp structure, it should be no problem to have the rotors foldable outboard of the blade extension. Where the real problems begin though are with the fact that two of the four baldes also have to angle downwards as well back, problematically requiring with two of the four spider arms to move in the vertical (in the same manner as when changing blade pitch), rather than remaining fixed. It may be possible to do something clever in brass but equally possible I may not be clever enough to do it. I'll have a look anyway.

 

The other related issue in long, thin as the main blades is always going to be strength, in terms of both their inherent thin-ness and the concomitant need to model them with a varying droop along their length. Some time ago I noted a sentence in the Flight article that may contain a solution:

52581895256_47b6dd0670_c.jpg

If the rotors are thick enough I may well be able to design a hollow tunnel down the length of that D section into which a length of brass tube can be slipped for strength, in the manner of a wing spar. Printing droopy rotors will not be a great idea from the support point-of-view but printed straight, I know the resin can be softened enough in hot water and then shaped to the required droop on a jig. Sounds simple enough...  🙄🧖‍♂️

 

Two things to work out then.

 

I hope you all got some nice pressies? Nothing modelling related here (unless you can count a warm jumper for cold days in the studio) but from Mrs B this absolute unit of a book from Cork University Press, which I'd coveted to the point of sin since it was first published:

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890+ page about nothing but the outrageous confusions of water and land...

 

More anon, peanut intak permitting....

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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1 hour ago, TheBaron said:

It's from that old Ealing Studios comedy: 'Highland Midges Galore!'

The qualifier is unnecessary as there is no such thing as "A Highland midge" 

 

1 hour ago, TheBaron said:

"snubber strut"

That sounds like a description of someone who is walking down main street with an air of overblown self importance!

 

That book looks VERY interesting too, what a great cover pic.

 

Having said that, I really can't imagine myself doing the amount of research and examination that is going into this to get it right. 

 

Which is probably why I stick to 1:72 scale!

 

Ian

 

 

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16 hours ago, TheBaron said:

I temporarily duped the parts around the vertical transmission axis

 

One of the lesser known (and morally dubious) functions in Fusion?

 

Your facility for deciphering photographs of the Heath Robinsonesque complexity of the inner and outer workings of the Wasp continues to amaze and delight, Tony

 

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17 hours ago, TheBaron said:

If it's a ny consolation Bill that's me every time I start up Fusion! 🤖

I do, honestly and deperately hope AND wish this were true Tony...

 

Colour me unconvinced but also accept my heartfelt thanks for trying to make me feel better buddy.

17 hours ago, TheBaron said:

Reasoning that this feature was at 45° to the rotor axis but needing to be aure my designs were coherent, I temporarily duped the parts around the vertical transmission axis and mocked up a snubber to test the hypothesis:

Could you do this action around an axis which will not remain throughout the modelling?


Could you arbitrarily decide on a different axis to maybe chamfer an unexpected shape temporarily but then revert after modelling the chamfer to the normal axis?

 

The answer to this question and more questions to ask will be given in the next edition of Resin Soap folks...

 

 

(I am still confused but whole heartedly pleased to be learning this stuff from you and the other guys Tony.

 

Happy new year, telling you this now because I may be away.

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On 26/12/2022 at 10:03, TheBaron said:

Who I immediately got confused with Scott Baio, star of that dramatic masterpiece: Joanie Love Chachi.... 🤮

 

Thanks a lot, thanks a whole lot. I had completely put that out of my memory and now you've gone and brought it back. Arghh...what's next? Happy Days?    :drunk:

 

Cheers,

Bill

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Foul evening here, gale and rain on the eves but a good fire lit in the front room to toast the hooves at whilst writing. The rotor hub is finished, mail first though.

On 26/12/2022 at 15:47, Pete in Lincs said:

Nice looking book. I used to love the TV series coast. I like the brass spar insert idea. Happy boxing day and may your snubbers never droop. 

Thanks on all counts Pete. Put the rubber on my snubber earlier....

On 26/12/2022 at 16:47, Brandy said:

That sounds like a description of someone who is walking down main street with an air of overblown self importance!

:rofl:Does sound like something sassy and street out of the jazz era doesn't it?

On 26/12/2022 at 23:18, bigbadbadge said:

Seasonal greetings to you and yours Tony, lovely work on figuring the rotor head.

Cheers Chris: same to you mate.

On 27/12/2022 at 07:35, Fritag said:

Your facility for deciphering photographs of the Heath Robinsonesque complexity of the inner and outer workings of the Wasp continues to amaze and delight, Tony

Most kind Steve: one endeavours to give satisfaction to the learned audience on here, knowing what they themselves are capable of.

On 27/12/2022 at 09:28, perdu said:

Could you do this action around an axis which will not remain throughout the modelling?

Exactly Bill.

Using an axis (dotted line below) as a construction feature, it has no volume, so doesn't appear as a object. Useful for generating a circular pattern of objects for things like bolts, rotor hinges & etc., or for revolving a flat profile drawing to create things like a tyres or other cylindrical features:

 52591713663_1cc7a77993_c.jpg

22 hours ago, Navy Bird said:

Thanks a lot, thanks a whole lot.

:rofl:

In Scotland you aren't allowed to refer to Joanie Love Chachi by its title on superstitious grounds; instead it must be referred to as 'the Illinoisan play'....

 

The flappiong hinges needed finishing before the hub and these in themsevelves have several layers of detail to take into account top and bottom. Undereneath there is this trefoil plate and bolt for example:

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 - along with on top another couple of superimposed plates and the drum shape of the damper pack. On print orientation/support ground sI kept the hinge and damper pack as two separate parts , so added a locating peg and hole to help with construction later on:

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I'll also use some brass tube to fix the flapping hinges onto the central spider:

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The hub spider incororates a significant number of defining features so the above parts had to be as exact as possible in  shape and proportion, primarily due to the curved junction between the arms and their bevelled edges, which have to follow the curves all the way around both top:

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 - and bottom:

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The it was time to add the hinges back in to check the overall set of shapes against each other:

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With that looking Ok, it was on to drawing some profiles along the snubber strut to create its shock-absorbing materials:

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This was followed by another duplication around the central axis to create the other three set of snubber-rubbers:

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As with the damper packs/flapping links, for printing/support purposes a square hole was added in the bottom of the hub spider for the top of the transmission to fit into during assembly:

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All of that then fitting in turn onto the main transmission shaft:

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The next set of jobs then are in a similar vein, adding the rather agricultural looking forging of the pitch change arms to the left side of each flapping link, followed by the spider arms angling down from them to those rubbers sleeves at the base of the transmission.

 

Rendered views of the current status to end on then:

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Put the Ferroro Rocher down. You'll spoil your tea.

:bye:

Tony

 

 

 

 

 

 

 

 

 

 

 

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Absolutely stunning engineering Tony your attention to the smallest detail is second to none!

I am in awe of your skills in this medium that I for one do not understand!

Looking forward to watching this come to fruition in the fullness of time

 

      Stay safe and Seasons Greetings                Roger

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I wonder if Airfix ever take note of all this work and enthusiasm for the subject?  You never know, after all this work, suddenly they might get serious with many requests and make a 1/48th Scout and Wasp rather than yet another Spitfire or a 1/24th Hellcat? Hmmm... 

Edited by AMB
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Saturday lunchtime and that can mean only one thing. You have to guess what it is though.

 

On 29/12/2022 at 08:27, Hamden said:

Looking forward to watching this come to fruition in the fullness of time

Thank you for your kind words as always Roger and the very best to you also.

On 29/12/2022 at 09:17, perdu said:

After that nothing can spoil...

Just wait until these become printed objects though Bill and reveal the unanticipated - that's when the 'ripe' modeller's oaths will really start to flow, (that bespoke lubricant which it is customary to apply in copious quantities during construction).... 😁

On 29/12/2022 at 10:01, AMB said:

I wonder if Airfix ever take note of all this work and enthusiasm for the subject? 

Redefining 'circumspect' if they are Adrian! 😁

 

Now then. To return to a problem I've previously discussed on here: the feasibility of building a working blade fold that won't snap at the first outing. To illlustrate in  modelling terms the problems posed by manouevering the blades into their support cradle, there is nothing to surpass  @perdus masterpiece in 1/72 here

 

Note particularly how the two foremost blades have to ssimultaneously fold both backwards (simple enough to do) and downwards (harder), rotating along their respective pitch control axes to drop below the rearmost blades and slot into the lower cradle restraints on either side.

 

Problem identified, but then how does this work on the real thing?

 

Well, I don't know very much about flying and aeronautical engineering as you know to your cost/chagrin/amusement, but it did occur to me that any situation which involves leaving a control mechanism under strain for extended periods is proably Not A Good Thing in operational terms. One of the reasons I previously bought a copy of the PNs for the Wasp is that aside from being (as the majority of RAF/RN ones are) a model of explicatory clarity, their descriptions of how to operate a winged/bladed thing fill in the blanks left by purely descriptive/historical sources. In this instance, Chapter 4 - 'Rotors and Transmission' contains a useful 7-step guide on how to fold the Wasp's rotors into the cradle.

 

This yielded the missing part of the puzzle about how a person might rotate their parts without straining anything and is best demonstrated with a sketch of the kind I like to use when working out such problems:

52593753403_7444590a73_c.jpg

The upright spider arm (which bolts onto the pitch change arm at top) is telescopic in design with an item called a 'pip'- pin halfway down it which can be released so that the blade(s) in question is effectively decoupled from the pitch controls. The blade then be rotated downwards without feeding any tension forward into said control run. Both @Ex-FAAWAFU and @Anthony in NZ had kindly shared images previously which included views of these pins pulled, yet I didn't then understand what I was seeing until reading a description of the actual process.

 

As the rotors and manner in which they are controlled and regulated involves a lot of things happening at once, there is by necessity a lot going on with regard to  the interaction of the various components up top. To get the spider arms correctly oriented around the transmision axis and plugged into the rotors, I first had to build outwards from the existing flapping link in order to create the blade extension. Remember this blade extension has to rotate, so first I mimicked the actual rotor designs by building a mounting pin on the link that will sit inside the extendion:

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A bit of a Dalek's eye-stalk in that state so if I bung the extension on in semi-transparent form you can see how the structure will operate:

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Out of caution I've designed in an option to have some brass tube down the centre, for strength. This may not prove necessary but I won't know for sure until I have a physical part printed and checked or strength. I'll also need to split part of that extendion lengthwise of course in order to be able to join it around the inner mounting pin when building.

 

Built into the inner end of that extension is a collar which one end of the pitch-change arm is bolted onto. For added fun, the front face of this collar not only angles outward from the centre of the blade extension:

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 - but is also rotated downwards in a clockwise manner which is subtle enough in many photos that you'd miss it altogether (as I did on my first attempt):

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The florin drops however when you go on to build the pitch change arm and wonder why it bangs up too close to the flapping link and you realize that not only is the collar rotated slightly, but the pitch change arm is also with so that it cants over at the required angle to meet the spider arm from below:

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As is often the case, you work a lot of this stuff out in the process of designing the next part and then wondering 'but why doesn't  -?' before looking closer at things like relative angles in photos. That pitch arm itself is a bit of a beaut in its own right to have to knock together, with lots of 'challenging' non-regular curves and profiles:

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In terms of structural strength on the pitch control spider I'm using a hybrid resin/brass system to avoid bits snapping off in the fullness of time. The bottom spider arm  and 'elbow' have a hollow centre section to accept brass tubing as additional bracing against the upper spider arm:

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That lower brass tubing in turn enters the rubber sleeve for about 0.6mm in order to stop the part flexing:

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The upper spider arm will itself be made from two telescoping sections of brass tube (with the aforementioned pip-pin halfway down its length to release for folding purposes), a smaller brass insert at the top pinning it into that somewhat ungainly shock absorbing joint on the inner end of thenpitch change arm:

52597733691_5559c75041_b.jpg

A note on method: I forgot to mention earlier that with this number parts meeting each other at various angles in there, it's very easy to get tunnel vision on individual sections and forget to check  the combined result of matches reality; the biggest issue in this respect to get right were the upper spider arms. Due to their prominence within the appearance of the Wasp, it's important to note that although these arms angle inward and tilt towards the neighbouring rotor, they do so at a characteristic 'slope' which means from certain viewing angles the two nearest arms appear will sometimes appear broadly parallel to one another (one of those phenomena that once seen you wonder how you missed it).

 

To reproduce this state of affairs, a crude 'cage' of blanks was rigged around the transmission axis so that by incremenatally adjusting the original part, the copies would consequently move in an identical manner. It was then just a question of tweaking this rig in three dimensions until it matched what can be seen in photographs:

52597246672_66d932c296_b.jpg

Such a  process was pretty good at revealing any inaccuracy in surrounding features - revealing for example that I'd initially gotten my pitch change arms slightly too long and low in profile. With both of these issues addressed it was then fairly strightforward to add in the remianing sections:

52597246702_48961006e4_b.jpg

This whole pitch change mechanism was quite honestly one of the key parts of the Wasp which I was dreading having to build, producing more than one occasion when I thought 'I ain't going to be able to get this to work' due to parts not aligning or simply having that number of design drawings spread around such a small volume of space:

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Renders to end (these give a good idea how much brass will be needed for this part of the Wasp):

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Regional views:

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Sorry about the frargrance: I was eating smoked haddock fishcakes whilst writing this up and the breath is a bit Lyme Regis' Cobb on a hot afternoon.

 

:bye:

Tony

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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5 hours ago, TheBaron said:previously bought a copy othe PNs for the Wasp is that aside from being (as the majority of RAF/RN ones are) a model of explicatory clarity, their descriptions of how to operate a winged/bladed thing often fill in the blanks left by purely descriptive/historical sources. In this instance, Chapter 4 - 'Rotors and Transmission' contains a useful 7-step guide on how to fold the Wasp's rotors into the cradle.

Sorry about the frargrance: I was eating smoked haddock fishcakes whilst writing this up and the breath is a bit Lyme Regis' Cobb on a hot afternoon.

 

 

:bye:

Tony

This has to go down as the WIP post of the year! Absolutely brilliant and captivating reading. You should have been a detective….or are you???

 

 The only thing I can comment on is….yup your fish breath was a little ransid whilst reading that.

Mints next time please :tooth:

 

Thanks for such brilliant inspiration throughout 2022, and many modelling successes for 23!

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On 12/31/2022 at 2:11 PM, TheBaron said:

it's important to note that although these arms angle inward and tilt towards the neighbouring rotor, they do so at a characteristic 'slope' which means from certain viewing angles the two nearest arms appear will sometimes appear broadly parallel to one another (one of those phenomena that once seen you wonder how you missed it)

 

I think I’m lacking enough brain cells to understand.  Henceforth I shall follow along in bemused admiration.

 

What I will say is that having seen how complicated (and Heath Robinson) the vital workings of this thing were, I’m so extremely glad I never went up in one.

 

How could all those essential and intertwined bits ever have worked for any length of time as they were supposed to?  One shudders at the thought of it…

 

 

 

 

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Is this still a helicopter build, or has it turned into something Star Wars related? That rotor assembly looks so much like some spacecraft thingy (I know, I'm all technical today :rofl:)

 

:gobsmacked:

 

Ciao 

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19 hours ago, Fritag said:

How could all those essential and intertwined bits ever have worked for any length of time as they were supposed to?  One shudders at the thought of it…

Engineering dear boy, simply wonderful engineering...

 

Rather like the engineering Tony is developing skills in as well as his complex mental abilities with the Fusionometer.


Tony please accept the flabber from my over heated ghast sir and my apology for ever doubting you would notice the rotative part of the rotor head and its associated spiderings

 

Nailed it buddy, absolutely nailed it.

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'Tis surely a thing of beauty, or as much a thing of beauty a Wasp could ever be.  Wonderful head working Tony. 

FYI, getting the first 3 of those snubber arms in place will be easy. The 4th one? Not so much. (Been there albeit in a smaller scale)

On 12/31/2022 at 9:11 AM, TheBaron said:

I'll also need to split part of that extendion lengthwise of course in order to be able to join it around the inner mounting pin when building.

 

Or could you just use a simple buttress thread on the shaft part with a corresponding female buttress inside the blade?  In that scale I think you could get away with a female thread printing successfully though it might be tricky getting the threads to align with the blade fully home

 

 

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On 12/31/2022 at 6:11 PM, TheBaron said:

how a person might rotate their parts without straining anything

Useful information to know if you want to avoid a strange gait and funny looks. Do they also have instructions on how to make the tassels go in opposite directions?

 

That's about all I can come up with I'm afraid.  Any comments about exquisite design, and fabulous detective work have already been made.

 

Happy New Year to you and yours.

 

Ian

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Wow. Complicated - I've just crossed over the threshhold from saying "yeah, I think I got it now" to "yep, whatever you say Tony" when it comes to how helicopters work!

 

Magnificent Obsession...

 

Happy New Year,

Adrian

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It's truly damp and cold and grey and windy here today; one of those bitter January afternoons in which you idly wonder exactly where you went wrong in not reaching this point in life without possession of a tropical villa a la Ian Fleming. Mind boggled just now in looking up Goldeneye to find you can actually stay in it!

https://www.theflemingvilla.com/the-experience/

No pricing so I guess if you have to ask &etc. etc....

 

Rambling back to the main business of the day though:

On 31/12/2022 at 20:07, Anthony in NZ said:

You should have been a detective….or are you???

After watching Glass Onion at the weekend (fabulous fun) I must confess to now covetting a fez Anthony and wanting to lie in the bath smoking cigars for days on end between cases.... 😁

On 31/12/2022 at 20:32, bigbadbadge said:

My gast is flabbergasted Tony, more amazing detective work and plotting, great stuff. Happy New year to you and yours.

 

Thanks Chris - the very same to yourselves over there.

On 01/01/2023 at 22:49, Fritag said:

I’m so extremely glad I never went up in one.

<Removes fez and places it on the bar>

Don't like to brag Steve but I had several hundred hours in my log book by the time I was 12....

VertiBird.jpg

On 02/01/2023 at 09:05, giemme said:

Is this still a helicopter build, or has it turned into something Star Wars related?

Spinning that rotor hub around whist working on it Giorgio I kept thinking I heard the The Blue Danube....

danube14.jpg

On 02/01/2023 at 18:17, perdu said:

and my apology

None needed Bill 😁 This whole whole last week or so has just involved walking a tightrope of how-does-that-work-can-it-work-at-this-scale, with no guarantee that there would be a positive outcome. Mercilfully Westland seem to have had future modellers in mind in making their structures self-evident once you clock what's going on - which is a far from immediate process in my case! 🤣

20 hours ago, hendie said:

FYI, getting the first 3 of those snubber arms in place will be easy. The 4th one?

Watch me break parts during assembly.... 😬

20 hours ago, hendie said:

it might be tricky getting the threads to align with the blade fully home

I've had more enough tricksiness from this part of the Wasp Alan thank you very much; playing it safe and going for a vintage Airfix-type solution to the problem. 😁

(There is, as always, an elegance of purpose to your suggestion but I fear that threaded approach is out of my league)

6 hours ago, Brandy said:

That's about all I can come up with I'm afraid.

More than en:rofl:ugh Ian!

5 hours ago, AdrianMF said:

I've just crossed over the threshhold from saying "yeah, I think I got it now" to "yep, whatever you say Tony" when it comes to how helicopters work!

That's characteristically kind of you kind Adrian but the most that I'm doing is just joining up the dots from visual evidence - I really miss @Ex-FAAWAFU not being around when it comes to experiential knowledge of flying these things.

It's a pale substitute but there is this 1982 gem from the wonderful Horizon series' that used to be on BBC2 back in the day.

 

Quite without meaning to I got a bit carried away this morning and ended up building the main rotor blades. I hadn't intended to go that far but after working on the blade extensions I just decided it would be eaier to complete the job now, whilst details are fresh in your head, than to come back at a later stage having forgotten what was involved. I actually liked Alan's idea about having a blade extension setup that screwed together but in the end, a sense of my limitations kicked in and I went for something which Airfix might have used back in the 1960s, namely gluing two halves together to lock the part onto a central mounting spigot that allows it to rotate without slipping outward:

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This is basically a simplified version of the dual bearing system that sits inside there on the real thing so not an original notion. Outward of that feature you can see the way the remainder of this blade extension uses a square peg to attach the remaining length into place at the correct orierntation. Splitting that part midway means I only have to worry about tidying up a short pair of seams top and bottom when fitting those parts together, rather than along the whole length of that part. I've also revised the length which the brass reinforcing rod travels out from the spider so that it adds support in the critical region point where strain on the structure will be greatest. Beyond this extent, the part should be strong enough to handle the weight of the blade.

 

The - I'm calling them 'fingers' - which each main rotor blade bolts onto tested my patience heavily last night, due to the manner in which they emerge and spread out of the flared ends of the extension forging:

52604392512_b29b9d0811_b.jpg

The struggle was mainly between the size and spread of those circular 'fingertips' top and bottom in relation to the angle at which the cone-like feature preceding it spreads out from the forgin. this led to a prolonged and tedious back and forth between both sets of features on the timeline until they matched what could be seen in photos taken from various different angles. Again part strength is a major concern here due to the effects of any undue pressure on those fingers when folding the blades back into the support cradle.

 

As to the baldes themselves, well thanks to Anthony I had some ground-truth dimensions from measurments of an actual Wasp he so kindly conducted a while back, added to which I found some additional leading particulars in the Wasp performance manual. The original Flight article describes the blades as having both taper and twist so I was pleased to find actual dimensions for root and tip chord widths listed in the manual to help with the former.

 

This, along with an accurate (non-drooped) figure for the rotor diameter let me first produce a dimensioned mockup using blanks in order to check that these figures all matched up with the overall dimensions of the airframe:

52605044573_bc892e198d_b.jpg

With that investigated I could then build the blades for real - simple enough to using airfoil profiles at either end for a straight loft. From (predictably rare) nearly end-on shots of the blades, these airfoil shapes appeared to be symmetrical, something which I undertand is not unusual in helicopters? As to the twist in them, well, I can't see that in photos so am obviously missing something. It's not critical at this stage though as for the blade droop itself, I'm going to produce that after they're printed, softening them in hot water and  forming them on a jig. If necessary I so can include a twist then if it's prominent enough to be required. At that stage also I'll insert the metal reinforing rod down their centres for strength:

52604540546_5e54ca62f0_b.jpg

To minimize the risks of any damage  to the blade mounting, I designed a PE insert that will fit inside the fingers themselves (in a hopefully unobtrusive fashion) to provide additional support for the weight and strain of the blades:

52605044563_85af51bc3b_b.jpg

Once decoupled from the pitch control spider, folding the actual blades back is a simple enough process of removing one of the locking pins from those fingers so that the remaining one on the leading edge side acts as a pivot.

 

You know I had to give it a go.

 

But had I left enough space in my designs for the butt end of the blade to rotate within the space between those fingers?

 

By pure skill utter good fortune I had!

52604791044_03da706ec8_b.jpg

:yahoo:

Locked into place using metal pins and with that PE insert for extra strength, I'm pretty sure that should withstand modest downward pressure during use now:

52605044633_e9b76832e7_b.jpg

Folded back like that you can also see the packing blocks top and bottom of the blades which provide parallel surface to locked inside the  blade extension for flight.

 

Duped around the transmission axis:

52604540601_75632b1224_b.jpg

Undersides:

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Closer:

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Avec chassis:

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Amazing how with the rotors on it suddenly starts to look like it could fly!

52604038907_b9711b1afa_b.jpg

 

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Renders unto Caesar:

52604038957_7a201de3ea_b.jpg

 

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Calling this one 'Dawn off Portland' as I like the way the light strikes the blades:

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Anyway with that lot done it's time to take stock of the parts inventory:

52604853251_7bba1426fa_b.jpg

Excluding large parts of the airframe and engine/oil system, I've been slowly adding smaller features to the .stl library and have such a number now at this stage that I probably need to start some test prints to ensure that my guesses on some of the finer tolerances are going to work out as physical objects. The major oil pipe runs will need something custom done in Fusion in the support line due to their length and fragility, whilst the Nimbus I might have to split into at least three sections for printing purposes. The MRGB I might get away printing as a single object supported from below - we'll see how that supposition works out in due course.

 

This is probably a god point then to pause the design work in Fusion then and spend any free time over the next wek or so putting together support structures for the first major print test(s). As with the Vixen, this won't be to start building the actual model but to act as a testbed to identify any unforseen problems with either printing or assembly.

 

In contrast to today's gloom, yesterday the rising earthshadow was outrageously pure in colour at dusk at dusk:

img

Adieu from the shade mes braves.

:bye:

Tony

 

 

 

 

 

 

 

 

 

 

 

 

 

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7 minutes ago, TheBaron said:

After watching Glass Onion at the weekend (fabulous fun) I must confess to now covetting a fez Anthony and wanting to lie in the bath smoking cigars for days on end between cases.... 😁

On 1/1/2023 at 9:32 AM, bigbadbadge said:

Hahaha.....go on, do it :D

Flemming Villa does look lovely I must say.  If this helps make you feel any better this is where I was (got home last night) in Queenstown.  On a 1912 Steamer heading to a bay for BBQ lunch on a lake, 30deg C was a little too much for me though.  I will add that I dont normally live an extravagant lifestyle like this as 'I am but a simple man'.  But my sister and her family were over from Woking in UK and I hadn't seen them in 9 years.... we did the touristy thing with them you know...now I have no money LOL

7uoreq.jpg

 

Anyway I changed my mind....this is your best post ever!  I am at a loss to understand how you do this...but that's what makes this thread all the more interesting (as well as the fact that this is one of my favorite helicopters of all time!)

 

Thanks for giving me something to read when I was away in my 'down time' I am in awe.

Cheers Anthony

 

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12 hours ago, TheBaron said:

That's characteristically kind of you kind Adrian but the most that I'm doing is just joining up the dots from visual evidence - I really miss @Ex-FAAWAFU not being around when it comes to experiential knowledge of flying these things.

 

I'm still here!  Or, if you would prefer, I'm back.  Yet to do a full catch-up, but which aspects of my experiential knowledge is that you wish to tap?  [Think carefully before you answer this question, unless you really want full details of a run ashore in Alongapo, Philippines].
 

Edit:  RUN ashore, definitely not “drug” ashore.  Bloomin’ auto-correct & ham-fistedness: a deadly combo.

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11 hours ago, Ex-FAAWAFU said:

 [Think carefully before you answer this question, unless you really want full details of a run ashore in Alongapo, Philippines].

Oh yes Crisp, full disclosure of course, must be de rigeur, non?

 

Tony.

 

s much as I love this working out, passionately would not be overegging the pudden, I did not notice mention of the blade trim tabs along the trailing edges, two to a blade as shown in all the best photographs.

 

I.e. 4531378205a.jpg

 

Obviously we do not expect German glidey bombs to be stuck in the hangar with the  Wopse. :)  

 

From below I have this little dark gem showing just one of said trim tabs. The very black bit to the left of the blade seems to be the root of the next blade around. :) 

3jcv0G.jpg

 

Is that not a dangling pip pin or two hanging from the rods?

 

My word yes it is.

 

Brilliant exposition again Tony and a damned fine photograph of some sky...

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