Hudson wing question

[AltcarBoB]

I am painting a 1/72 Hudson and I am wondering what the small black (might just be a shadow) oblong depressions along the wing leading edge top and bottom near the wing tips are.

 

I have a thought that they might be a high lift device of some sort but I really have no idea.

 

https://images.app.goo.gl/Y7mJYpAp3fxN6kpe7

[Jamie @ Sovereign Hobbies]

That is indeed a fixed slot.

 

Here's a clearer view. They seem to normally paint the slot openings dark - I don't know why but it's a slot there none the less

[KayFranz]

These are air flow intakes (quasi-slots). Normal slots could not be used due to de-icers (those black elements on the leading edge of the wing). The hole itself is quite narrow from the bottom, the black areas in your photo are mostly paint. Look for Hudson's photos in the New Zealand museum, it is clearly visible there.

Edited July 27, 2020 by KayFranz

[Jamie @ Sovereign Hobbies]

Here's a view down through them

 

[AltcarBoB]

Thanks @Jamie @ Sovereign Hobbies and @KayFranz that's a pair of good answers. I had heard of Slots but thought they were moving parts which I now know are called Slats.

 

 

[Magpie22]

Yes indeed, they are slots. The Hudson has a highly tapered wing planform which is prone to stalling at the wingtip, a highly undesirable state of affairs, which can render the ailerons ineffective and induce a lack of lateral control. At high angles of attack, the slot allows high pressure air from under the wing, just behind the airflow stagnation point, to pass up through the wing to the upper surface where it adds energy to that low pressure flow, delaying the breakaway that causes the wing to stall. 

 

I think that KayFranz may be confusing his slats with his slots. Slats are mounted forward of the wing leading edge. They can be fixed or retractable, and do much the same job as slots, i.e. delay the stall in the area behind..

 

Peter M

Edited July 27, 2020 by Magpie22

[Graham Boak]

Well, the original slats were mounted in front of the leading edge but the retractable kind (as on the Bf.109 and many other types) fitted flush with the leading edge when closed. They stuck out in front of the line of the leading edge when open.

 

mnemonic:  Slats open slots.

[Work In Progress]

Slat/slot trivia: a technology simultaneously and independently invented twice in 1919, both in Germany by one Gustav Lachmann, and in England by a group within Handley Page (Fred claimed it himself on the paperwork but it is known to have been a team effort). Lachmann and HP wisely did a deal to avoid a tedious international patent squabble and Herr Lachmann moved to England to work for Handley Page, where he designed the Harrow and the Hampden.  HP then made a significant amount of money licensing the idea to manufacturers around the world before WW2, notably BFW / Messerschmitt.

 

Lachmann's work did not prevent him from getting jailed as a suspect enemy alien in England during the war, but after HP leaned on the government he was at least allowed to continue to work on HP design business while in prison, which just shows how ridiculous the whole thing was.

Edited July 27, 2020 by Work In Progress

[RJP]

The HP slat also figured in a suit between Handley Page and Curtiss in the 1920s.  HP asserted that Curtiss used the device without permission (or payment) on the Curtiss Tanager which had beaten HP's Gugnunc in the Guggenheim competition.

 

That Curtiss was one ugly aeroplane.  The Gugnunc, I think, looks pretty sharp.

[Aeronut]

Quote

Lachmann's work did not prevent him from getting jailed as a suspect enemy alien in England during the war,

Would you believe you can download Lachmann's MI5 file from the National Archive!

I did it recently along with Raoul Hafner's file. Lachmann may have had Handley Page on his side but Hafner had Lord Brabazon on his (amongst others), and as a result only spent 5 months in internment. 

[Work In Progress]

Thanks, I will have a look at that

[Steve N]

Here are a couple of closeups I took of the wing slots on a Lockheed C-60.  Same exact wings as the Hudson. 

 

Cheers!

 

Steve

 

 

[AltcarBoB]

I had started painting the underside slots black before asking the question. So I have compromised the underside slots are black the topside slots are the same extra dark sea grey as the rest of the topside.

[Graham Boak]

One tip is to tone down the black for a more realistic finish - this also permits the use of black to represent intakes/outlets or just holes.

 

PS the C-60 wing is the same as the Hudson wing in this area but has an extended chord inboard over the Fowler flaps.