Gunsight page updated

[nabe]

I update my historical gunsight page.
 http://www.ceres.dti.ne.jp/~nabezo/AH/gunsight/gunsight.htm

 Update Mk8 for F4U.
 Update Type1 Mk2 and GM2 Mk2 for Spitfire and Typhoon.
 New PBP-1 for La-5FN and Yak-9

Thank you,SkyHawk and PapaRomeo!

[Westy]

Great work!! Thank you very much!

-Westy

[Grifo]

Great job, I like it!  
If I find something about gunsights of italian planes I'll send to you but...
please correct manufacturer's name, the correct spelling is:

MACCHI  

Thank you and Salute!

[funked]

         

[nabe]

>MACCHI

oops
Sorry, I will correct it right now

[Andy Bush]

Good info!

What was the significance of the '100 MILS' label on the F4U sight?

Andy

[nabe]

>What was the significance of the '100 MILS' label on the F4U sight?

Just an eyecandy

[fats]

Is the Revi 16B AH gunsight correct or should the reticle be _exactly_ like Revi 12D's?

I am talking about the center of it: in the Revi 16B real world picture there's some sorta reflection making it appear there is two reticles, one that is little higher than the other thus making it appear that the center is closed and not open like Revi 12D.


//fats
p.s. and it's not Luft-Waffe but Luftwaffe for what it is worth.

[newguy]

awsome nabe! Thank you very much  

newguy

[Andy Bush]

nabe

I take your answer to my question as "I don't know.".

If the accompanying photo by 'Meza' is taken from real life, then the '100 MILS' caption probably refers to the size of the reticle diameter...most likely the outer circle.

A second possibility is that this refers to sight depression, but I doubt it. Few WW2 sights were depressible.

Andy

[nabe]

to fats

>I am talking about the center of it: in the Revi 16B real world picture there's some sorta reflection making it appear there is two reticles, one that is little higher than the other thus making it appear that the center is closed and not open like Revi 12D.

I have not so many datas and information, so I only can do is to trust these photos.

Revi 16B's duplicated reticles are... the one is the normal image and the other is the image that reflector's back side reflect the normal reticle image.

I think if Revi16B's reticle center was open, at least the horizontal line should be seen as open too. But horizontal lines are not open. So I conclude Revi 16B's reticle center is close.

Although, I have not so many data, so there are possibilities that it is my mistake.


p.s.
Luft-Waffe is my mistake  

[nabe]

to Andy

>If the accompanying photo by 'Meza' is taken from real life, then the '100 MILS' caption probably refers to the size of the reticle diameter...most likely the outer circle.

Yes, Meza took this photo. He own Mk8.

100 MILS means that the outer circle is the circle is 100yards object with 1000yards distance, 30yards object with 300yards distance , and so on.

So, if you aim the fighter plane at the outer circe, the plane is about 150yards away because fighters are almost 15yards wingspan. With bomber 300yards away because of 30yards wingspan.

So I think,outer ciecle means bomber's 300yards aiming line and inner circle means fighter's 300yards aiming line.

But, in the AH this circle(100MILS circle) means nothing because I don't know how to calculate the exact size of 100MILS on the gunsight image. So it is just an eyecandy

[Andy Bush]

There you go!!

Let's fine tune your words a bit...

The technique of using the size of the gunsight circle (the correct term is 'reticle')to estimate target range is known as 'stadiametric ranging'.

The general idea is that a small angle will subtend a certain sized arc at a given range. The angle in this case is the '100 MILS' value...a 'mil' being about 1/17 of a degree. The relationship is one foot equals one mil at 1000 feet range.

In this example, the outer reticle diameter is calibrated to equal 100 mils in size. We then use this reticle to estimate range by comparing it to a target of a known size. Usually this is the target's wingspan.

Consequently, a target with a wingspan of 45 feet will just fit inside the outer reticle at a range of 450 feet.

This 45' wingspan was chosen to represent a typical WW2 fighter wingspan (that value is actually a little too large...most WW2 fighters had spans less than 40 feet). The 450 foot value represents a nominal optimum firing range...probably the range that the guns were harmonized at.

You are right about the sim and reticle size...we never know how valid a sight's dimensions are in a sim. Too bad since in RL this was such an important factor in A2A gunnery.

Andy

[nabe]

to Andy

Yes, it is very significant in real life.

But...the unit to use in firing range is yard, not feet . 450feet is D1.3k. I can't shoot enemy at this distance .

Let's assume the optimum range is D300 (100feet). The typical bomber wingspan is 100feet(B-17 have 107feet wingspan). So B-17 just fit to the 100mils circle means that the distance is about 100feet.

Also, we assume to aim P-38(its wingspan is about 52feet). P-38 at 100feet distance just fit to inner circle(50mils).

[Andy Bush]

nabe

Not to be rude...but I don't have a clue as to what your last post said.

We were talking about the F4U gunsight...not ranging units in AH.

Andy