Reflector gunsight

[paddy]

I have a very rare reflector gunsight
This is a std MkII with an adjustment ability of 5 degrees on the side to allow for the drop of rockets as apposed to 303 calibre bullets

As a result of these and their success the manufacturers put a more refined version in production like this where the mechanism is fully enclosed and the top of the sight is square.

I am looking for any info on my sight, I have researched this a bit and have some answers but i want to see if anyone comes up with the same conclusion as me.

PS note how the std box has been modified to take the adjustment ring

 

[moon puppy]

Oh my!
I got nothing for you but I'm sure @Sharkmouth will be along with all the manuals and if the SN is there he might even have usage history!

I've always had a hard time judging distance/range. can't imagine how they did it back in the day.

 

[paddy]

That's what i need, someone who knows where to look on the net
You didnt really need to judge a range. The guns were harmonized at , say 100yds, you set the site too 100yds and the base /feet to the wingspan of an aircraft and when the wings fill the graticule its at 100 yrds and you can fire

 

[moon puppy]

say 100yds, you set the site too 100yds and the base /feet to the wingspan of an aircraft and when the wings fill the graticule its at 100 yrds and you can fire

I"ve read that the gun site on a Mustang had a dial a target, you selected which aircraft you're firing out and the ring would change based on wingspan and you fill the ring. Pretty high tech stuff back then!

 

[Heavens Eagle]

You have pics of two different sights Paddy, which is which? Super interesting!!!!

 

[paddy]

The first one is mine. The second one is the production one

 

[paddy]

OK so what i have found is this is a MkII L

an adaptation of the Std MkII which didnt have the adjustable glass plate The MkII was the std British gunsight also used in the P51. made by Barr and Stroud. Its really hard to take a picture of this powered up as in the aircraft it would have had a dimmer switch on the instrument panel. Also its designed to be focused on infinity and the camera keeps trying to put it in focus on the glass but in reality if you were looking at Rommel in his car 400yds away the sight would appear in focus on the car not on the reflector glass anyway here goes

But turn the light down and

You get a better idea.
The horizontal lines move in and out from the centre spot as you adjust the wingspan of the target, the idea being that when the wing span fits between the 2 lines either side you can fire knowing thats the point of convergence of your bullets.

As your bullets travel to the target they drop because of gravity, An RPG drops approx 4x as much over a range than bullets so the sight glass could be tilted 5 degrees to allow for this so you could hit Rommel with your rocket and still shoot down a couple of ME 109s on the way back to base for tea and medals.

Roland Beaumont found in his Typhoon that the whole sighting thing obscured the target as above and he developed a system by removing the reflector glass completely and the range mechanism and just projected a dot on the the windscreen its self.
A lot better providing you could judge range and were only doing ground attack. You also needed an armoured glass screen as these were optically correct. A std screen produced two dots...

This is not about modelling so i hope its not out of place .

 

[moon puppy]

so you could hit Rommel with your rocket and still shoot down a couple of ME 109s on the way back to base for tea and medals.

Come now, it's not about medals, it's about who buys rounds and gets mentions in the daily dispatches.

Really neat you got it to power up!

 

[Heavens Eagle]

@paddy "This is not about modelling so I hope it's not out of place"

My friend it is 100% what modelling is about. This is the fun part of research and history on these subjects.

 

[Sharkmouth]

This is not about modelling so i hope its not out of place .

My friend it is 100% what modelling is about. This is the fun part of research and history on these subjects.

That right @Heavens Eagle, this is an important part of model building for many! Learning about the real-deal. @paddy, I might have something in my library but I am suffering form vertigo at the moment. Sitting at a PC is no problem but the rapid side to side eye movements make it extremely hard to type, find the scanner, and reply. It seems you're doing well but maybe I will have something to confirm your findings.

@moon puppy, that gunsight simply replaced the span dial with a custom one listing targets:

 

[Rhino]

OOooohh! Where didja get THAT! This bit of aviation history is awesome!
Jolly Good!

 

[Sharkmouth]

@paddy, I'm sure you found this thread but... If not:

"Early SpitI and HurriI

GM2 MkI --- Mounted in a Hurri angled to match reflector plate opticly with the wind screen to account for double image distortion. Similare problems were encountered with the spit. Version that should be in our Spit Mk1 and Hurric Mk1. Used in early Beaufighters.

The first change in the design was made in 1941 when the circular reflector glass was replaced by one 114 mm (4.5 in) square, the circular design having been found to have slight optical aberrations. This modification was designated Mk IIs, later Mk II*, fixed gun reflector sight. Existing sights were retrofitted with new sights heads, and the circular sight heads are now highly prized by collectors. The dimming screen was discontinued, as it was said to be rarely used.

When rockets came into widespread use, a special version of the GM2 was designed in co-operation with Farnborough, to allow for the increased gravity drop of these projectiles. The reflector screen was made to tilt forward by the pilot from 0 to 5 degrees depression, according to airspeed and the known drop of the missile being used. This modification, which involved the replacement of the sight head, became known as the type 1 Mk II conversion, and the sight then became the Mk IIL.

GM2 - MkIIS or MkII* --- What HTC currently uses in all spit, hurri and typhoon. Notice pronounced rounding of reflector plate corners.

GM2 - Mk2L --- Used in Hurri IIC\D and Typhoon. Dial changes the angle of the reflector glass by 5 degrees for bombs and rockets."

Source:

Spitfire MkI and Hurri MkI MkII Reflector Gunsight

Spitfire MkI and Hurri MkI MkII Reflector Gunsight

bbs.hitechcreations.com

 

[Sharkmouth]

Another link which refers to your gunsight at a Type I Mk II conversions, aka MkIIL. Click image of gun sight to see article:

 

[paddy]

This where it gets tricky because the sight above is substantially different to mine.
The link says its a Mk1 but its not really, its a Mk1 with a MkIII top on known as a square top, mine is a round top.

but your article is the first i have seen that even mentions a MkII L so well done

Square top

my round top

 

[paddy]

OOooohh! Where didja get THAT! This bit of aviation history is awesome!
Jolly Good!

Ha ha yes i had quite a few, i used too deal in them a bit, i knew of an old guy who had tea chests of these, after the war you couldn't give this stuff away and he picked up a whole load because he thought the lenses might be useful , He had anything with lenses in like gun cameras etc, when he died i got about a dozen from a guy that knew him, various models from oval glass Mk1, square glass MkII ...I gave one to Tangmere aviation museum and another to Duxford fighter legends for their Gladiator restoration as that needed quite a rare model i happened to have, sold the others on E-bay for £3-400 each
These days they go for £1000 plus.
I kept the MkII L i have above as it was the only one i had eve seen and too this day i still haven't even seen a another picture of one.

 

[Rhino]

The story is almost as priceless as the gunsight! Bravo!