Blackburn B20 – flap type?

Just a thought but it maybe be worth having a look at the flaps on the Botha, designed and constructed around the same time as the B20

Maybe, but I don’t see why.

It takes a while for BAe Systems heritage to reply; first the question has to be forwarded to Brough and I think that the volunteer up there only works on Thursdays.

Maybe they did more work on it for the Firebrand because they felt it could be improved on from their experience on the B20?

No reply from BAE Heritage yet.

Robin

Its unlikely to be as clear-cut as that. The B20 was designed to a 1936 spec for a patrol flying boat while the B37 Firebrand was designed to a 1940 spec for a carrier-based fighter, completely different roles with differing technical solutions.

Blackburn did a lot of work on Fowler flaps for the Firebrand starting in 1939, so it stands to reason that the same type was used for the B-20.

Thankyou for the information Schneiderman.
Only the B2 came up on initial search so I have sent them an email.

Robin

The Blackburn archive material is held at Brough, its possible that they may have the information you require. They can be contacted here

http://www.baesystems.com/en/our-company/heritage

Absolutely!
Unless landing inverted was in the plan – I believe someone did this with a small biplane a couple of years back – but it is far from common practice!

Trying to get detail on rare types is not exactly easy. They never have the benefit of such things as pilots’ notes.

I wonder what happened to the second prototype that was cancelled half way through building… scrapped I suppose.

Robin

Thanks for the kind response: Frise flaps would be a bit silly really, as their benefit shows when deflected trailing-edge upwards.

Thanks Richard – sounds like a Fowler flap to me too.
A bit of a strange description… I thought all types of flaps were ‘camber-changing’ and ‘inboard of the ailerons’… Better than no description though.
Does Mr Jackson include any photos of the flaps deployed? … because my next decision is going to be to what degree were the flaps intended to increase wing area and to what extent did they droop. I.E. how curved was the track?

Robin

A J Jackson in Blackburn Aircraft since 1909 says the flaps were ‘Hydraulicaly operated metal-covered camber changing flaps that ran on curved rails inboard of the fabric covered frise-type ailerons’. Which sounds like a description of a Fowler flap to me.

Richard

Thanks for the response Graham.
The ailerons are Frise, but the flaps have quite a bit more chord under the wing than they do. Unfortunately there seem to be no photos on the web of the B20 with flaps extended.
If anyone is harbouring a photo of the aircraft with flaps down that would be of great help.

Robin

Not just Frise? As on the Spitfire and Halifax, to name perhaps the most obvious two. Both Fowler and Youngman would have obvious flap tracks and/or hinges, with a much smaller chord on the upper surface if at all.