http://www.SimHQ.com/simhq3/sims/air_combat/gunsights/

Thoughts, comments, etc. here!



------------------
John Sponauer
Senior Editor
SimHQ.com
jsponauer@SimHQ.com

Informative article.

Robert Johnson commented that his childhood hunting of rabbits and bird (i.e. moving targets) really helped to hone his gunnery skills allowing him to hit what he was shooting at over Europe.

I now know why my convergence setting of 650 is just wrong. I've been having a hard time hitting my target, using correct lead, yet my bullets just fly over my target.

Thanks Andy, makes the mud a little clearer in the arena.

B.

Andy,

Once again youve hit the bullseye. As a WW2 Gunsight collector, I enjoy your in-sights on gunsights and thier operation.

Now if I understood you correctly, the size of the reticle circle shown on my Mk2 RAF gunsight would be used to intersect both wing tips (~35' on a fighter) at 1000' range, right?

I wonder if that was the same for Luftwaffe as it was for the RAF and USAAF? The circle on the early BF109 gunsight is about the same as that of the Spitfire. But the Revi16B used in the FW190D, Me163, and Me262 is alot smaller in diameter.

Perhaps it has to do something with the distance from the pilot's eye to the reflector's glass plate? I know that by moving my head closer to the gunsights (real ones) that it affects what my eye sees as the diameter of the reticle. And that must surely affect the gunranging.

Can you comment on that aspect of the gun geometery (eye to gunsight)? I imagine the picture of how light passes through a lens relative to the focal distance is what is in view (literally) here.

Which means somehow in all the turmoil and G forces in a dogfight, the pilot's eye still must be within a certain distance (focal range) AND within a visual cone from the gunsight. I believe its about 12 inches, can you confirm?

Your articles are always worth the read.

AV8R

Real Spitfire Mk2 Gunsight pointed at WW2Fighters:

Real BF109 Revi3D Gunsight pointed at WW2F:

Real Me262 Revi16B Gunsight pointed at WW2F:

Excerpt from the Revi Owners Manual:




[This message has been edited by AV8R (edited January 12, 2001).]

AV8R

I see what you are saying.

The question of how the pilot's eye-to-gunsight distance impacts the accuracy of stadiametric ranging is one that I'll not make a specific answer to since I can't go out to a real jet and verify my ideas.

I'll assume that the sight was usable throughout the 'normal' range of pilot head positions. Would it still be so if the pilot were to put his eye right up to the gunsight? I don't know...possibly not, but this situation has no relevance to real life...we simply did not do that! There was no reason to. Additionally, the ability of the pilot to move his head opposite (rearward) from the 'normal' seating position would be much less due the seat back.

One aspect of your pictures...in the three shots, the reticle is spanning approximately 1/2 of the wingspan. For the first two (35 mil reticles), this would indicate a range of about 500'. In the third picture, the reticle of the Revi-16 is also spanning about 1/2 of the wingspan, and the reticle is clearly smaller than the Revi-3 picture. I think that may be a 'visual illusion'.

Consider this. If the actual range is 500', then the relative size of the target should be the same in all three pictures...but in the third, it is clearly not. The gunsight spans about 1/2 of the wing, but the target is too small, ie, further away than the first two.

It is this difference in viewing perspective that confuses the comparison of the two Revi sights. Until I knew what the two look like under similar circumstances, I can't say anything about this difference.

If I had to guess, I'd assume the reticles were the same...but the Allies changed reticle size during the war, so why not the LW also?

Andy

Andy,

Hmmmmmmmmmmmmmmm

Ya know what.... the smaller ring reticle on the 1944 based Revi16B probably does make sense in light of your saying they shifted from bomber wingspans to fighter wingspans.

Then the Revi16B having their hash or tick markings extend beyond would deal with the heavies, no?

Makes sense to me.

Now back to the eye-to-gunsight focal distance issue... by moving my head AWAY from any of these reflector sight, results in the reticle ring getting larger. And only about 6 inches differences makes about 2X in size. Also, by moving my head about 5-10 degrees off center bore makes the gunsight dissapear from view on the reflector.

This tells me that unlike games where your head placement is independant of gunsight picture, the real world does seem to make a big difference. Another departure of sims from reality. So in real life, the pilot had to have a steady state placement of his head to the gunsight to get a clear targeting picture. This may account for why they always said to get in close and fill your windscreen with the enemy. Just my 2 cents.

AV8R

Hay Andy this is the one I did for myself ,I got better thanks

Navigator

P.s. I Liked your BnZ stuff to


[This message has been edited by navigater (edited January 13, 2001).]