Jump to content

Westland Wasp HAS 1: 'Ambuscade Flight: XT778'


Recommended Posts

12 hours ago, Ex-FAAWAFU said:

RUN ashore, definitely not “drug” ashore.

 

As a welcome back pressie, Crisp I’m letting that one go without comment.  I can’t tell you what it’s costing me ;) (welcome back).

 

14 hours ago, TheBaron said:

putting together support structures for the first major print test(s).

 

Am now getting over-excited at the prospect.  Is it christmas again?

 

  • Haha 5
Link to comment
Share on other sites

17 hours ago, Anthony in NZ said:

On a 1912 Steamer heading to a bay for BBQ lunch on a lake,

Are you sure you're not living a Benoit Blanc movie for real over there Anthony? :laugh:

(Lucky devil - that view from the deck looks fabulous!)

15 hours ago, Ex-FAAWAFU said:

Yet to do a full catch-up, but which aspects of my experiential knowledge is that you wish to tap?

PN's have been enormously helpful but confirmation appreciated on following:

1. Are naval helicopter pilots a breed apart?

2. Flap and droop stops limit vertical motion of a blade whilst snubber struts restrict lateral motion? (i.e., these three operate in concert to ensure blade stability?)

3. Daft question on the tailplane - it is a fixed feature? (i.e. non-movable, or have I missed something in the controls?)

 

15 hours ago, Ex-FAAWAFU said:

Edit:  RUN ashore, definitely not “drug” ashore.  

Strong Stephen Maturin/laudanum vibes here Crisp. Have you checked on the sloth....?

4 hours ago, perdu said:

I did not notice mention of the blade trim tabs

You're quite right right Bill. :nodding: I haven't worked out yet what I want to do about them as resin will be too fragile in this case and I need to mull over the best way to insert such features as PE, for strength.

With so much brasswork involved in proceedings already, another reason to pause at this point is a crying need to catalogue the existing metalwork and output them as unfolded designs. Not a task I enjoy quite honestly.... :rolleyes:

4 hours ago, perdu said:

 

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

Once you notice them - they're everywhere! :laugh:

Not sure my neighbour should have one dangling from the underside of his Qashqai though....

3 hours ago, Fritag said:

Am now getting over-excited at the prospect.  Is it christmas again?

Every day is Christmas Day on Britmodeller Steve. 😁

16 minutes ago, Brandy said:

I'm definitely looking forward to see how all this prints...

 

Am not entirely disinterested myself as it goes Ian! 😁

 

Nothing significant to report today as currently trying to get my wife's mobile number swapped over between phone companies and it's going about as well as you can imagine....

:bye:

Tony

 

 

 

 

 

 

 

 

 

 

  • Like 4
Link to comment
Share on other sites

1 hour ago, TheBaron said:

PN's have been enormously helpful but confirmation appreciated on following:

1. Are naval helicopter pilots a breed apart?

2. Flap and droop stops limit vertical motion of a blade whilst snubber struts restrict lateral motion? (i.e., these three operate in concert to ensure blade stability?)

3. Daft question on the tailplane - it is a fixed feature? (i.e. non-movable, or have I missed something in the controls?)

 

No, Jack, I have not debauched your sloth!

 

1.  Obviously.  [Noting that 'a breed apart' can be good, bad or even both simultaneously...]

2.  Yes.  Snubber stops pretty old-fashioned (not meaning to imply that the dear old Wasp is anything other than cutting edge modernity, of course).  Usual term is lead/lag, and it's usually controlled by a damper rather than a stop; the aim is to avoid sudden lurches in lead/lag, particularly at low rotor RPM ("Nr"), because that can lead to ground resonance and a whole world of pain.  You definitely wouldn't want the lead/lag of a blade to be constrained in flight; aerodynamics will take care of that for you.  So it really only comes into play at lower Nr as you engage and/or disengage rotors.

3.  I think so... sort of.  I am not a Waspie (though I managed to blag a couple of trips; my first Lynx squadron, 829, still had a couple of Wasp flights at the time in 1989), but you are certainly correct that it cannot be controlled by the pilot.  It's possible that it could be adjusted on the ground, but I don't think so - not sure I can see why it would need to vary.  The point of a horizontal stabiliser is generally to provide a better cruising attitude (more efficient for the main rotors but also more comfortable) by 'flying' the tail up or down (down in the Wasp case, I think; same in the Lynx - it's an inverted airfoil section).  Some other helicopters achieve some of the same effect by having the tail rotor at an angle (often in addition to a horizontal stab), thus introducing a vertical thrust moment as well as the more obvious yaw moment - with the advantage that the thrust is variable with power, whereas the effect of a fixed horizontal stab is variable with airspeed.

 

 

  • Like 4
  • Thanks 1
Link to comment
Share on other sites

2 hours ago, TheBaron said:

Nothing significant to report today as currently trying to get my wife's mobile number swapped over between phone companies and it's going about as well as you can imagine....

Oh THAT well, tell me about it...

 

Currently trying to introduce Debit card details for a newly issued card myself, to various online etc. providers of essential services so I feel the pain too, Tony.

 

Blade tabs eight fresh pieces on your etch panel perhaps?

  • Like 3
Link to comment
Share on other sites

Another great entry from the Gent in the Emerald Isle. With addendum by Crisp from dark blue land. Tornado had rubber snubbers built into the wingsweep jack's. Pip pins. A hollow cylinder with a round or T shaped head. Two small ball bearings stick out near the end. Inside the cylinder is a spring loaded rod. Push or pull the 'pip' on the top and the bearings collapse back into the cylinder to allow fitting or removal of the pin. Basically a removable bolt.      Horizontal stab. Look at a Huey. Obviously an inverted aerofoil.  Don't forget your homework, kids. 

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

2 hours ago, Pete in Lincs said:

Obviously an inverted aerofoil.  Don't forget your homework, kids. 

About that homework

 

 

 

IMGP0040-zpseg5vcriz.jpg

 

4075720440-c1ff6476ef-z.jpg

 

Perhaps less obviously chaps...

 

I suspect although I don't know that Huey has the inverted aerofoil to cope with frequent massive pitch changes in service to allow for troops emplaning during varied ops, that way some of the asymmetry can be dealt with aerodynamically.

 

But that is mere surmise which would explain why Wopsy has neutral lift built in.

  • Like 3
Link to comment
Share on other sites

21 hours ago, perdu said:

I suspect although I don't know that Huey has the inverted aerofoil to cope with frequent massive pitch changes in service to allow for troops emplaning during varied ops, that way some of the asymmetry can be dealt with aerodynamically.

An aerofoil section isn't much use in the hover, you need foward air speed to make it work.

  • Like 1
Link to comment
Share on other sites

1 hour ago, Dave Swindell said:

An aerofoil section isn't much use in the hover, you need foward air speed to make it work.

I know that, just considering the Huey can get massive load shifts with its large cabin whereas Wasp is fairly CoG centred whether loaded of not, I don't know enough about the aerodynamics of load shifting to pontificate.

Actually wondering why the H-60 series have such a massive stab tilt in service. 

Love to learn these things Dave, might see about studying it for pleasure.

  • Like 1
Link to comment
Share on other sites

Don't know about chopper aerodynamics but with a fixed wing the horizontal tail surfaces provide a downward force, not a lifting one. Main reason being that if the wings stall (lose lift) they will drop and the tail surfaces remain effective for recovery. If the tail provided lift and stalled, the tail would drop and recovery would be next to impossible. Some aircraft such as the Ilya Muromets did have a lifting tail (evident by how far forward the wings are, nowhere near the CofG) and there are stories of it's awkward landing characteristics - reduce power to land and you also reduce airflow over the lifting tail causing it to drop! Not very desirable!

 

Ian

  • Like 2
  • Confused 1
  • Sad 1
Link to comment
Share on other sites

Inching towards getting the first print on later in the week, due to most of the famille currently stricken with lurgey of various kinds...

image_thumb2.png?imgmax=800

 

Digging back into the thread for some info on scaling the other evening, I came across this prophetic post from Alan back in mid-November

On 17/11/2022 at 20:46, hendie said:

Contrary to popular belief, the Wasp/Scout isn't as diminutive as people seem to think. I have my Scout placed next to other 1/48 builds and it's really not much smaller than other a/c I have in the cabinet.  In 1/24 it's going to be an attention grabbing beast, particularly with all that Triffid Nimbus stuff going on.

Boy is he right.

On the standard Mars 2/3 printer, at 1/24 one half of the cabin alone eats up the entire plate area!

52614394296_cd10646c1f_k.jpg

Rather glad of the investment in the Saturn 2 at this stage as it simply wouldn't be feasible to work with resin at this scale any other way.

 

I usually avoid running beta versions of software for anything mission critical but as the latest one for Lychee introduces some potentially useful new features, I decided to give it a punt for the cabin & nose section test:

52613884707_e2da0f7b15_b.jpg

Every time I do up supports like this it reminds me of the old Wild Mouse rollercoaster at Littlehampton back in the 70s. If the wind was in the right direction and you were sitting at the back, a  blizzard of fag ash used to hit you in the face on the way down the big drop....

 

Although I had anticipated the issue, it's still something of a shock to see the sheer volume of print supports required at this scale! Thankfully, along with the existing 'paint support' functionality, Mango have a new 'inline' tool in the support interface of this beta, one which allows you to automatically generate lines of supports along a given path - an absolute godsend at the larger scale.

 

Another size-related function I didn't really have to have to worry about too much previously at 1/72 was that of suction. With the parts here physically occupying such large volumes of space at 1/24, there's a very real risk of the final print emerging distorted (or just as serious, pulling away from the FEP) during printing, resulting from the push/pull effects of such massive items moving up and down in the resin. The latest version of the software now contains a suction analysis tool which helped here with orienting that main cabin/nose component in such a way as to avoid the hollow space between cabin floor and bottom of the airframe setting up a potentially problematic drag in the print fluid.

 

It took a bit of spare time getting to know these new functions here so next time out it should hopefuly be a bit quicker. One final thing which I know I'd promised @Anthony in NZ I'd look at is the effects on detail of producing the  Wasp in 1/32. To this end I knocked up a quick size comparison whilst Lychee was open using the MRGB as a litmus - you can see the size differences visually here:

52614652894_ae5f3a29b2_b.jpg

In terms of physical dimensions, approximate heights of that MRGB are then:

1/24th  = 20mm

1/32nd = 15mm

1/48th = 10mm

 

Given those value I reckons that some of - but by no means all - the detail on that component would be preserved by the print resolution of the Saturn 2 down at 1/32, but by 1/48 it will have vanished. When I set that piece up for a print then Anthony I'll include a 1/32 version as 'ground truth' for you to eyeball. Oh what a world of possibilities....😁

 

Hope your Sundays are going Ok.

Off to light the living room fire now as it's already dark and cold at lunchtime.

:bye:

Tony

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  • Like 17
Link to comment
Share on other sites

A Sunday update with a Comedy hero at the top. Though he invented the Lurgi AFAIK, so tell the family to blame him and get well soon.

That is indeed an impressive amount of scaffolding for the cabin halves. 

46 minutes ago, TheBaron said:

problematic drag in the print fluid.

There's a lot of it about!

The different scale Gearboxes look impressive and could prove to be a good sales tool, perhaps? 💰

Have a great week and try to stay well clear of the Lurgi!

  • Thanks 1
Link to comment
Share on other sites

On 1/9/2023 at 2:31 AM, TheBaron said:

Given those value I reckons that some of - but by no means all - the detail on that component would be preserved by the print resolution of the Saturn 2 down at 1/32, but by 1/48 it will have vanished. When I set that piece up for a print then Anthony I'll include a 1/32 version as 'ground truth' for you to eyeball. Oh what a world of possibilities....😁

Woohoo....I reckon it will look perfect!  Just imagine that next to my Phantom :wub:

 

You're right it does look like a rollercoaster scaffold!  Another awesome update (one I will try not to get too excited about the prospect of one in 1/32....keep calm Anthony, keep calm:hypnotised:)

 

Keep warm buddy, we're thinking of you guys over there with power prices etc.  Cant be easy

 

Cheers Anthony

  • Haha 2
Link to comment
Share on other sites

Back after 10 days away from BM and my own workbench I am not yet equipped to cope with this stuff you're doing Tony.  I'll need a little more time to warm up...  As you were.

  • Haha 4
Link to comment
Share on other sites

Addendum re aerodynamics.  I said that the horizontal stab was there to help control the attitude in forward flight, which is true - but I then said some kind of nonsense about comfort.  Their Lordships were never prone to investing much money in the comfort of us intrepid aviators; the reason for controlling attitude within certain limits is far more likely to have been to provide a stable weapon platform, able to drop a Mk.44 (when designed) or Mk.46 (later in Wopsie life) torpedo within a sensible launch envelope, thus minimising the chances of the weapon failing or even breaking up after entering the water badly.

 

That would suggest that the stab was optimised to provide stability at c.90 kts, was which the standard weapon release speed for the Wasp (from 400’, to give them 200’ vertical separation from the Sea Kings).  Lynx the same, only 120 kts.

 

AS12 even more so, I imagine - but I don’t know whether the missile fit was envisaged at the design stage.  
 

Crew comfort?  A likely story!

  • Haha 8
Link to comment
Share on other sites

Good evening everyone. I have some prints to show you this evening but in time honoured fashion will delay matters pedantically by replying to posts first...

On 08/01/2023 at 14:21, Pete in Lincs said:

That is indeed an impressive amount of scaffolding for the cabin halves.

As events proved, this was somewhat optimistic on my part Pete and was the one bit that didn't work out as planned! 

Or as I believe Spike himself once averred:

'We haven't got a plan so nothing can go wrong!' :laugh:

On 10/01/2023 at 09:13, Anthony in NZ said:

keep calm Anthony, keep calm

:rofl2:Take your tablets Anthony - I have some news for you in a moment... 

On 10/01/2023 at 10:40, mark.au said:

As you were.

Remaining as I was sah.

Whatever that might have been..I forget now.... 

21 hours ago, Ex-FAAWAFU said:

Their Lordships were never prone to investing much money in the comfort of us intrepid aviators;

This seems an historical constant regarding how power treats service.

 

Thnx for those torpedo envelopes Crisp - good solid operational material of the kind this thread feeds upon.

 

So the Saturn has been quietly doing its thing in the cupboard over the last few evenings and I now have three sets of test prints to examine:

52620807652_6d45f77434_b.jpg

 

52621755930_e106a6b0f0_b.jpg

Despite the absolutely filthy FEP in the print vat (which badly needs replacing) the printer just kept churning out quality parts as if it wasn't being asked to print through a semi-opaque window. The only failed resion amongst the whole bunch was the rear underside of the cabin area; if you remember in my previous I talked about the dangers of suction in this area and I think in the end the sheer volume of the piece proved too much for the supports, as they shifted during the print to give wavy where straight should be:

52620807572_4ce6d917a8_b.jpg

It's a simple enough problem to solve and really results from me being such a noob at printing 1/24 when it comes to the increase in part strength required. Next time out I'll both thicken the floor/underside areas and print them as a separate section to avoid the cabin area being too big a single part. The rest of the part turned out nice and smooth though, with very little going to be required in the way of sanding:

52621579594_aac11de1fc_b.jpg

As I had a bit of time to kill until the second set of prints was ready I kept myself amused by gluing the two halves together for an 'Alas, poor Yorick!' photo opportunity:

52621579649_3b4f0568b6_b.jpg

Only at this point did the sheer size that of the model start to hit me! Is it possible to be afraid of your own work? :laugh:

 

In all the following shots you're seeing the parts fresh out of the resin, which is to say, they've been washed but not cured in UV yet or tidied up in any way. This won't be a full parts inventory, just an initial look over of representative parts freshly hatched and still on their support structures.

 

The rear wall of the cabin also gave me pause upon realizing the width of the beast:

52621755760_e11f7e96a9_b.jpg

Similarly feelings too at handling the main rotors:

52621800378_8efa377a79_b.jpg

Printing these required some creative thinking in the custom support dept. due to their obvious length/width relationship. To solve this I designed  vee-shaped verticals support in Fusion that would run the length of the leading edge but which only had a contact point 0.14mm wide to assist with removing the blades from them later. In uncured condition they come with built-in rotor droop:

52620807622_7979f9e5aa_b.jpg

Once cut free it will be interesting to see if I can get the droop and twist starting in the right place pre-curing...

For the pipes of the oil system I used the same 'vee' method of vertical support, combined with print supports added in Lychee:

52621322126_6c2d472056_b.jpg

Despite the thinness of the parts in question, this seemed to work quite well, though at 0.45mm ⌀, the oil scavange pipes in the middle of the three there may well need replacing by wire at the building stage due to their fragility. By contrast though, I think that the MRGB support pylons will work out Ok as resin, just so long as the brass main driveshaft bears the bulk of the weight:

52621322141_d60b2ce3fa_b.jpg

The quality of detailing on the MRGB exceeded my expectations as a printed item:

52621322201_da67543f8a_b.jpg

 

52621800558_d99df541de_b.jpg

Ditto with the front and rear of the reduction gearbox, which were equally sharply delineated down to the last bolt:

52620807752_b29f84b3bd_b.jpg

The new version Of Lychee has introduced a slightly different way of thinking about the use of anti-aliasing in printing and I must say on the strength of these ribbed sleeves for the spider arms, it handles small concentrated areas of detail with verve:

52621579789_623ab31222_b.jpg

By contrast, larger sections like the boom have a pleasing smoothness about them, and don't look like they requiring much work later in the matter of clean-up:

52621321991_e572e0947c_b.jpg

Probably just as well with the number of rivets it's going to need draped along its length....

 

One issue I encountered repeatdly on the Vixen and again here on the Wasp as the need to remove any excess liquid resin from the inside of hollow parts. Previously I'd done this by pumping compressed air down one hole in order to force any residual resin out of the other drain opening but recently hit upon the idea of making drain holes large enough that you can use a needle and syringe to pump IPA directly into the patient to sluice them out and yes this is suddenly starting to read like a post-mortem report....

52621800483_54bf69f236_h.jpg

Anthony - this next bit is for you in thanks for all the Wasp measuring. I not only test printed the MGB at /132 but had a crack at the Nimbus also, in order to give you a sense of how much detail remains after the Alice in Wonderland treatment down a scale:

52620807797_9d72dfc696_b.jpg

Uncured resin like this always looks a little waxy but I'll get  some UV on them in the next couple of days:

52621322221_65b617c6f8_b.jpg

 

52620807832_28d50fd764_b.jpg

 

52621800548_cf2595b14c_b.jpg

Aside from the preservation of detail down at 1/32, the other issue that impressed me here was that I was able to get away with printing the engine like that with just a few supports along the underside and yet the compressor ribs etc. all stayed in place. The 1/24th version I split into three and printed vertically but wondering if I need to do that now. I'll take a better look at it tomorrow with the supports off to compare the difference.

 

Anyway, this is everything I've printed up until now:

52621756055_c6fb348f71_b.jpg

Over the next few days those parts'll get removed from their supports and cured in the UV station, then we can have some fun whacking a few of them together to see what it looks like as a test assembly!

 

Bon nuit mes braves.

:bye:

Tony

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  • Like 31
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...