Gunsight questions

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wallydog
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Gunsight questions

Post by wallydog »

I've always been curious about how the internal and external gun sights worked in the p-40. The sight is so different from both the spit and mustang and the external sight is off to the right so would love to know how it worked if anyone knows.

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CodyValkyrie
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Re: Gunsight questions

Post by CodyValkyrie »

The main sight on the P-40B/C is a reflector, and essentially parallax free, being a precursor to modern HUD systems. The iron sights are offset in case of a failure or otherwise and can be physically aimed down by shifting the pilot's viewpoint. The reflector site shares a lot in common with the Spitfire's (because it IS the same sight). It is the British Mark II if I recall correctly. This glass on the MKII represented is from the early war years, and was later replaced with square glass. The reflector was made by Stroud Ltd. To collectors, this MKII with the oval glass and Stroud reflector, is one of the rarest gunsights.

The MK14 gunsight on the P-51D is leaps and bounds beyond the Mark II, compensating for aircraft maneuvering by having a gyroscope added to it, making it extremely accurate.

Here's a bit more information about WWII gunsights used by Americans, and it also includes a lot of information about other gunsights:
http://www.aircraft-gunsights.com/other-sights/
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wallydog
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Re: Gunsight questions

Post by wallydog »

CodyValkyrie wrote:The main sight on the P-40B/C is a reflector, and essentially parallax free, being a precursor to modern HUD systems. The iron sights are offset in case of a failure or otherwise and can be physically aimed down by shifting the pilot's viewpoint. The reflector site shares a lot in common with the Spitfire's (because it IS the same sight). It is the British Mark II if I recall correctly. This glass on the MKII represented is from the early war years, and was later replaced with square glass. The reflector was made by Stroud Ltd. To collectors, this MKII with the oval glass and Stroud reflector, is one of the rarest gunsights.

The MK14 gunsight on the P-51D is leaps and bounds beyond the Mark II, compensating for aircraft maneuvering by having a gyroscope added to it, making it extremely accurate.

Here's a bit more information about WWII gunsights used by Americans, and it also includes a lot of information about other gunsights:
http://www.aircraft-gunsights.com/other-sights/
thanks codyvalkyrie,

the spit had adjustable crosshairs and I'm curious to know how P-40 pilots used the sight without the crosshairs. Also wondering if the Iron sights were fixed or adjustable and if so how they were calibrated. I assume if there was a failure with the gunsight, the pilot would lean left to alight the sight but how would they gauge distance

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Re: Gunsight questions

Post by CodyValkyrie »

wallydog wrote:
thanks codyvalkyrie,

the spit had adjustable crosshairs and I'm curious to know how P-40 pilots used the sight without the crosshairs. Also wondering if the Iron sights were fixed or adjustable and if so how they were calibrated. I assume if there was a failure with the gunsight, the pilot would lean left to alight the sight but how would they gauge distance
All good questions. The Mk II used in both the Spit and P-40 had adjustments for range, etc., I believe, but I'm not sure about the crosshairs. It could either be another feature of the device, or a revision from a different reflector setup. Not too sure, although I've seen both crosshair sets on the Mk II if I remember correctly. Generally, on any of the early sights the reticule didn't move much. At best you could adjust for range, which changed the size of the crosshairs etc. The sights sometimes had ticks in them for different ranges or load outs. Most fighting was done inside a few hundred yards, so you didn't need a lot of fancy equipment. It was more of an art, which is why the guys who practiced deflection shots were so renown for their shooting skill. With sights like the K-14, it took a lot of the guesswork out, as everything was compensated for. As long as the data put into the sight, shooting was pretty damn accurate. The early sights didn't have these features, hence why there isn't much glass for the optic.

As for the iron sight, it's likely that when they converged and sighted the guns, they also set the range at something like 1,000 yards, or whatever the ground crew were told to put them at. It's adjustable I'm sure, but probably not from within the cockpit and it's done during the sighting process. They would sometimes set up a target and lift the tail and tune it and converge all at once, much like a rifle. Convergence is the range at which the bullets from the wings cross paths, which put a lot of firepower into a single point. Very devestating of done correctly.

While all functions of the Mk II are not simulated, I can assure you that the P-51's K-14 is an extremely realistic depiction of the actual sight, minus bulb changes. It even has the ability to adjust the range by twisting the throttle. In actual use, the pilot would have the gyro on, identity his target and adjust for wingspan (easiest if known), then adjust for range as necessary. If wingspan was not known, then you could figure out the range to the target, and adjust the wingspan by centering the target and adjusting the outer triangles to fit the wingspan. If from a side profile, a fast and dirty rule was to adjust it just slightly smaller than the length of the plane, as wings tend to be almost the same length. This makes it much easier to get accurate shots at all ranges while maneuvering. The K14 was designed well enough that they used it well into the Korean War.
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wallydog
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Re: Gunsight questions

Post by wallydog »

CodyValkyrie wrote:
wallydog wrote:
thanks codyvalkyrie,

the spit had adjustable crosshairs and I'm curious to know how P-40 pilots used the sight without the crosshairs. Also wondering if the Iron sights were fixed or adjustable and if so how they were calibrated. I assume if there was a failure with the gunsight, the pilot would lean left to alight the sight but how would they gauge distance
All good questions. The Mk II used in both the Spit and P-40 had adjustments for range, etc., I believe, but I'm not sure about the crosshairs. It could either be another feature of the device, or a revision from a different reflector setup. Not too sure, although I've seen both crosshair sets on the Mk II if I remember correctly. Generally, on any of the early sights the reticule didn't move much. At best you could adjust for range, which changed the size of the crosshairs etc. The sights sometimes had ticks in them for different ranges or load outs. Most fighting was done inside a few hundred yards, so you didn't need a lot of fancy equipment. It was more of an art, which is why the guys who practiced deflection shots were so renown for their shooting skill. With sights like the K-14, it took a lot of the guesswork out, as everything was compensated for. As long as the data put into the sight, shooting was pretty damn accurate. The early sights didn't have these features, hence why there isn't much glass for the optic.

As for the iron sight, it's likely that when they converged and sighted the guns, they also set the range at something like 1,000 yards, or whatever the ground crew were told to put them at. It's adjustable I'm sure, but probably not from within the cockpit and it's done during the sighting process. They would sometimes set up a target and lift the tail and tune it and converge all at once, much like a rifle. Convergence is the range at which the bullets from the wings cross paths, which put a lot of firepower into a single point. Very devestating of done correctly.

While all functions of the Mk II are not simulated, I can assure you that the P-51's K-14 is an extremely realistic depiction of the actual sight, minus bulb changes. It even has the ability to adjust the range by twisting the throttle. In actual use, the pilot would have the gyro on, identity his target and adjust for wingspan (easiest if known), then adjust for range as necessary. If wingspan was not known, then you could figure out the range to the target, and adjust the wingspan by centering the target and adjusting the outer triangles to fit the wingspan. If from a side profile, a fast and dirty rule was to adjust it just slightly smaller than the length of the plane, as wings tend to be almost the same length. This makes it much easier to get accurate shots at all ranges while maneuvering. The K14 was designed well enough that they used it well into the Korean War.
The P-51 is a true labor of love. You can really understand the the progression of technology. I wont hold my breath but it would really be nice to see the sight adjustments in the Spit at some point animated and working not sure if there were any adjustments in the the Warhawk.

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CodyValkyrie
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Re: Gunsight questions

Post by CodyValkyrie »

Wait a minute, I'm wrong (and right) about the P-40. The British models use the Mark II (try it). Let me get home and I will tell you a bit about what's in the American and AVG models.
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Bomber_12th
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Re: Gunsight questions

Post by Bomber_12th »

The gunsight in the American P-40B/C is very similar to that of the British sight, as it is still a reflector gunsight. In the original P-40B/C design, and as seen in the US versions, the gunsight was mounted on the floor, and projected through the armor glass and onto a flat glass plate attached to the windscreen (the armor glass itself had to be angled in the real aircraft in order to prevent distortion problems with the projection of the reticule through the armor glass). If I recall correctly, the gunsight used in the stock/US P-40B/C was the N-2 (of course without a sighting head, since it projected onto/through the glass plate attached to the windscreen).

(BTW, you can see how the armor glass was angled in these photos: http://a2asimulations.com/forum/viewtop ... 83&t=28152)
Last edited by Bomber_12th on 17 May 2015, 11:36, edited 1 time in total.
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Re: Gunsight questions

Post by Bomber_12th »

Speaking of gyro gunsights, the British were the first to develop/use them, as I recall, and before the K-14 became available, a number of ETO Mustangs were retrofitted with the British gyro sights, like the Mk.II Gyro Sight made by Ferranti. The K-14 was a US manufactured redevelopment/version of the British Ferranti Gyro Sight Mk.II. US manufactured Navy Mk.18 gyro gun sights also sometimes found their way into Mustangs/Thunderbolts/Lightnings, retrofitted in the field.
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CodyValkyrie
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Re: Gunsight questions

Post by CodyValkyrie »

Yeah, the N-2 sounds correct. They were stock fitted at that time from what I recall as well. The website I included has some decent information about the N-2, including other aircraft it was fitted to. I hadn't had time to look at the simulator and check, but it doesn't surprise me to hear it mght be an N-2 without the head and being projected onto the glass.

The N-2 is a pretty straightforward sight first used in the mid-30s, and there's not much to fiddle with. Adjustments were mostly done on the ground so it was sighted to whatever range was specified at the time, or as necessitated. In this regard the MK II had more features.

Of note, a team member here sent me a USAAF technical manual for the K14 that is extremely in depth and includes aerial gunnery for the system. If anyone is interested I might be able to publish some of it here, although I need to check with the person who sent it to me on DVD first.
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Re: Gunsight questions

Post by wallydog »

CodyValkyrie wrote:Yeah, the N-2 sounds correct. They were stock fitted at that time from what I recall as well. The website I included has some decent information about the N-2, including other aircraft it was fitted to. I hadn't had time to look at the simulator and check, but it doesn't surprise me to hear it mght be an N-2 without the head and being projected onto the glass.

The N-2 is a pretty straightforward sight first used in the mid-30s, and there's not much to fiddle with. Adjustments were mostly done on the ground so it was sighted to whatever range was specified at the time, or as necessitated. In this regard the MK II had more features.

Of note, a team member here sent me a USAAF technical manual for the K14 that is extremely in depth and includes aerial gunnery for the system. If anyone is interested I might be able to publish some of it here, although I need to check with the person who sent it to me on DVD first.
Look at that.. I didn't even notice the different gunsight in the Tomahawk until now as I always fly the avg version. Discover something new everyday.

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Re: Gunsight questions

Post by n421nj »

Very interesting however since the guns don't work I don't see the point in messing with the sights
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CodyValkyrie
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Re: Gunsight questions

Post by CodyValkyrie »

n421nj wrote:Very interesting however since the guns don't work I don't see the point in messing with the sights
For the same reason they put them in restored warbirds. Just so it's there. ;)
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wallydog
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Re: Gunsight questions

Post by wallydog »

CodyValkyrie wrote:
n421nj wrote:Very interesting however since the guns don't work I don't see the point in messing with the sights
For the same reason they put them in restored warbirds. Just so it's there. ;)
Yes I wholly agree. Looking at the P-51 MK14 sighting and the integration with the Throttle is something you can't fully appreciate until you see it modeled. I never knew P-51 pilots had this capability and were dogfighting that way. Seeing it for the first time in the P-51 was definitely a 'Wow..cool' moment for me. The level of detail in these A2A birds just begs you to play with all the knobs and switches and makes for a much more immersive simming experience.

Guns can be added via various 3rd party software but I think only A2A can give a full integration of ordnance with their planes in single and multiplayer. Hopefully they are considering it.

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Re: Gunsight questions

Post by wallydog »

Cody,

I came across this tidbit the other day regarding the AVG P-40 off of the Flying Tigers Association Website
http://www.flyingtigersavg.com/index.ph ... ing-tigers


"The P-40B was not equipped with a gun sight, bomb rack or provisions for attaching auxiliary fuel tanks to the wing or belly. Much of our effort during training and combat was devoted to makeshift attempts to remedy these deficiencies. The combat record of the First American Volunteer Group in China is even more remarkable because its pilots were aiming their guns through a crude, homemade, ring-and-post gun sight instead of the more accurate optical sights used by the Air Corps and the Royal Air Force.

-*Quoted portions from Way of a Fighter by Claire L. Chennault

It sounds like from Chennault, that the early P-40's used by the AVG didn't even have an optical sight and only the ironsights were used which is pretty incredible. There seems to be some confusion about whether the AVG flew P-40Bs or Tomahawk MKIIs but I've seen more resources claim they were modified Tomahawks IIs

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Re: Gunsight questions

Post by CodyValkyrie »

The AVG information is very hard to get all through. In our testing and development of the product, we found that a lot of information was not completely accurate, missing or misrepresented. One of the things that was found was that Curtis could not fulfill the orders of the AVG, and so the planes that they had were hand built essentially from spare parts on the Curtis production line. They're a mixture of the B/C models, and tend to be more rugged overall. I have an AVG book here that I'm going to have to go through and find some more details, but that's one of the first quotes I've heard saying that they didn't have sights. It's possible that this changed a bit later, but they might not have them early on.
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