Bertie McBoatface

February 14

On 12/02/2024 at 23:45, Mike said:

Don't be so melodramatic.

= Don't criticise the boss.

Fair enough, It's your website.

February 12

I wonder how many potential members have been discouraged from signing up by this thread because they now expect their English prose to be scathingly criticised here.

I wonder how many members who make brilliant models but maybe know that don't write so good are now feeling hurt.

How about a little tolerance guys, especially considering the many errors almost all of you have 'committed' on this thread.

February 8

I'm sorry guys and gals but all of my modelmaking activities are going to be shelved for several months at least. I don't want to discuss why but be assured that I'm ok. I just need to concentrate on real life for a time.

February 8

I'm sorry guys and gals but all of my modelmaking activities are going to be shelved for several months at least. I don't want to discuss why but be assured that I'm ok. I just need to concentrate on real life for a time.

February 8

Balsa armature and paper-mache. Your creativity quotient is way high.

February 6

I rely on Seamanship by John Harland (1984) for questions about how sailing ships actually work and Historic Ship Models by Wolfram zu Mondfelt (2005) for detailed information about how to build models of them. Both out of print but widely available second hand. There are many others guides too.

February 5

On 30/01/2024 at 17:49, Bill1974 said:

ships hunting subs did not want to be close / underneath the depth charge as it went off

Definitely not underneath. 😁

February 5

https://www.amazon.co.uk/Helicopter-History-Piloting-How-Flies/dp/0715389408

If you want to understand helicopters, that’s the book you need, people. As a Vulcan engineer transferring to Wessex in 1979 with no idea at all, a week reading Fay’s book brought me right up to speed. It was recommended to me by the rigger chief.

February 4

1 hour ago, Chewbacca said:

the best rendition of this kit I have ever seen

That is very impressive. I couldn't even manage the change to the forecastle length.

February 3

1 minute ago, Johnson said:

Hi FROGers,

Attempts at straightening the blades ended in complete disaster. They shrunk!!! I mean seriously shrunk! And even then didn't have the right bend.

The only solution, cut new ones. 0.75mm plastic card. The FROG blades were 1.04mm, which may have been a bit thick - 3"?

To give them the right droop they were held against a suitable kitchen object with the right degree of curve and very hot water applied until they held the shape. Mrs J. is very understanding, always has been. She didn't used to blink and eye when I was cleaning alloy wheels in the bath (from the VW Mk.1 Scirocco) in the early days. The new blades then had to be mated with the FROG blade clamps. They match the 4+ plans pretty well.

They look OK and may even pass Technical Muster (he said nervously).

The FROG blades, and the 4+ plans, have lots of lines on the blades, presumably to do with their construction, which I'll have to scribe on them.

Cheers,

Charlie

if you had posted that half an hour ago, you would’ve saved me a lot of time. Well done.

Those scribed lines are the edges of the blade pockets which are bonded to the rear of the spar of the rotor blade. (How do I remember all of this stuff from four decades ago when I don’t know what I had for breakfast? Oh yes, my brain worked better then, before I got married and had children!)

February 3

19 hours ago, Ventora3300 said:

Bertie as Engineering back up, it’ll be 100% accurate as well

If I've been volunteered for that job I need to expand on something I mentioned a few posts back - the irregular curve of a drooping rotor blade.

Some modellers make the radius of the curve the same from root to tip

That's wrong.

Italieri's 1/48 scale Wessex has the curve tighter at the tip than at the root. Wrong again!

This is what actually happens when a uniformly flexible beam is supported at one end, the root, and droops downwards under its own weight.

This is a strip of wood which I'm holding just in front of a wall. It's drooping under it's own weight as you see.

At point 0 the weight of the whole ten units is acting on the blade forcing it to bend relatively sharply. Moving outward, by the time you get to point 5, there are only 5 units of weight causing it to bend so the curve becomes more gentle. At point 9 there's only one unit of weight left to press the strip downwards and thats not enough to make it bend at all. Just like a rotor blade, it's actually straight at the end. A Wessex blade, if I remember properly is straight for maybe the outer ten to fifteen feet

It's very subtle and might not be noticed although 4+ has it spot on in the plans. (I have a similar profile in an Aeroplane magazine which has a constant curve. Yuk!)

And there it is in a photo from 4+

~~~~~~~~~~~~~~~~~~~~~~~

While looking for those shots in 4+ I found this:

A photograph of the head with blades moved forwards. I think you can see that they don't line up but all four have moved forwards (away from the camera) Note the pitot on the right.

And why isn't it wearing its cover? Corporal!

It's still hot, Sarge.

Hurumph! Fair enough lad, just testin' you.

February 2

This is impressive stuff. I paint figures but this is getting close to sculpting them.

February 2

I'm taking some time off for real life reasons. See you soon fellow froglets. 🐸

February 2

I'm taking some time off for real life reasons. See you soon shipmates. :pirate:

February 2

2 hours ago, Johnson said:

like the colour coded scalpels

Thanks. Saves fumbles. Blues for pointy one and reds for curves.

February 2

12 hours ago, Johnson said:

Ah… I think I know what you mean. The rotor head leans forward slightly? As shown in the 4+ plan.

Yes. I'm a but rusty on the details as it's been an astonishing 40 years since I last worked on a Wessex, but I think it is angled forward by 7 degrees.

4+ shows the rotors at 90 degrees apart. This is only true when hovering or rotors turning on the ground on a windless day. When the aircraft is moving through the air the advancing blades on the stbd side meet the air at their rotational speed PLUS the forward speed of the aircraft, while the retreating blades on the port side meet the air at the rotational speed MINUS the forward speed. In order to manage these forces that change 160 times a minute the head has drag hinges which allow the blades to move forward and backwards relative to their plane of rotation.

H is the drag hinge with a vertical axis of rotation.

(P is the pitch change rod which is nothing to do with this)

D is a drag damper that smooths out the movement

And the two Ms indicate how the blade moves around the drag hinge relative to the rotor head.

As I think you are realising, when the cab is parked with the rotor hub axis leaning forward, all four blades ease forwards by a few degrees. It's only apparent when looking up at the blades from underneath or down from above but a model of an articulated head helicopter llike a Wessex or Sea King with the blades set square looks totally wrong to anyone that knows. The Helicopter SIG don't know about this!

It's about that much.

(Rigid rotor helicopters like Lynx and Apache do not have drag hinges so their blades are perpendicular to each other on the ground. The advancing/retreating movements are absorbed by the flexibility of the solid metal head.)

If you want more info there's a nice pdf on the website below from Yorkshire Helicopters

https://yorkshirehelicopters.co.uk/wp-content/uploads/2017/11/aircraft-general-knowledge.pdf

14 hours ago, MrB17 said:

blade twist. (The root has a higher angle of incidence than the tip) Just like a propeller blade or washout on a wing.

That is not correct (for the Wessex at least). I spent years putting the things on and taking them off, looking along the length of the blades on every after flight and before flight service. There is no twist. The combination of droop and movement about the drag hinges might cause an illusion of twist on some photographs but the blades are actually flat.

February 1

1 minute ago, Johnson said:

Thanks Bertie!

Er... you're going to have to explain that in simple terms for me (imagine a 7 year old...)

Cheers

Charlie

I’ll draw you a picture in the morning mate.

February 1

That’s the way to do it! Fine modelling indeed.

February 1

Two bay biplane with only parallel struts. In a small scale. What a nightmarish challenge that must have been.

You have risen to the challenge magnificently! 👏

February 1

Here’s a tip for you.

Note that the curve of the droop is more pronounced at the root end than the tip.

Also will you be sweeping the blades forward about their drag hinges as articulated rotorheads always do when parked.

The rest of the build is so good that it would be a shame to miss this, as almost everyone does.

February 1

2 minutes ago, MrB17 said:

I’ve now learned to go look at the others in the GB while the glue or paint is drying, I’ll get the hang of this yet.

That is the thing that makes a good GB. We must circulate as though it was a party. I confess I’ve been a little busy in the boatyard to do my part properly so far. I aim to comment on all of the GB builds at least once.

February 1

11 minutes ago, Steve D said:

There is, indeed, no hope.......

True. If you haven't the strength to bend pins, what shall we do with you?

February 1

On 28/01/2024 at 15:34, mabbog said:

Anyone else notice the hideous alien face in there giving a thumbs up?

February 1

2 hours ago, Steve D said:

The answer is to use a pin punch, the pin is held in a tube and the rod inside the tube pushes the pin in, no (or very few) bending of pins ....

Cheers

Steve

I must be more skilful than you because I can bend a pin with any sort of tool. 😀

I’ve tried two different brands of pin punch, bent 1000 pins and occasionally driven the punch through the side of the boat. 🤣

February 1

57 minutes ago, Steve D said:

That's a major challenge, kit or no kit Bertie, looks like you have made a great start.

Nae bother. It'll be finished by Monday. 😆

51 minutes ago, Steve D said:

pin the first layer

Pinning is the suggested method of attaching the first layer, with glue of course and then removal of the pins before sanding. I thought the hardness of the plywood bulkheads would mean I'd be bending half of the pins and since the dog objects to me swearing (she immediately leaves the room) I'm using clamps instead.

55 minutes ago, Steve D said:

tee lights to light a propane torch

That could be quite an explosion! 🙀

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