Bore-sighting processes

[Achtungbaby]

Can anyone point me to a internet resource which has information on the typical bore-sighting standards for the Republic P-47D (first version razorback) and the Focke-Wulf FW 190A-5/6.

My two questions are:

1. Were the bore-sighting processes for World War II fighters essentially the same for both the USAAF and the Luftwaffe, i.e. position the plane horizontally and sight all guns/cannons to converge at a specific location down range?

2. Were the distances the guns/cannons sighted to, typically the same, i.e. 1,000 yards for the USAAF and ? for the Luftwaffe or were these distances generally pilot dictated?

Thank you for any assistance you can provide me.

If you have a perfectly good half-hour to kill here is my first effort at a World War II article: RAMROD I/II. Constructive criticisms invited.

 

[HoHun]

Hi Achtung,

>1. Were the bore-sighting processes for World War II fighters essentially the same for both the USAAF and the Luftwaffe, i.e. position the plane horizontally and sight all guns/cannons to converge at a specific location down range?

Yes.

>2. Were the distances the guns/cannons sighted to, typically the same, i.e. 1,000 yards for the USAAF and ? for the Luftwaffe

Well. Generally, the further from the centreline the guns were, the closer the convergence point. There was no requirement to sight all the guns on one plane to one point either - the cowl guns of German aircraft were often set up to fire parallel. From what I've read in Tony Williams' books, it was also possible to sight each in a pair of guns differently (as the RAF apparently did occasionally). Additionally, there were two different characteristic ranges for each gun - the distance in which the bore-line crossed the sightline in the horizontal plane, and the distance in which it crossed the sightline in the vertical plane. To make matters more complicated, the sightline could be off the centreline, too - in Luftwaffe single-seaters, it was usually displaced a bit to the right since it was assumed that the pilot would take aim with the right eye.

There is a P-51 diagram showing the various shapes the hit pattern assumes under different conditions, and as each pair of guns is set up differently, it looks a bit like a Spirograph drawing

The standard settings for the Me 109G-6 were:

Hub MK 108: vertical 400 m, on centreline
Cowl MG 131: vertical 400 m, horizontal 400 m
Gondola MG 151/20: vertical 500 m, horizontal 300 m

For the Fw 190A:

Cowl MG 131: vertical 400 m, parallel to centreline
Wing root MG 151/20: vertical 550 m, horizontal 600 m
Outer wing MG 151/20: vertical 550 m, horizontal 400 m

For the P-47:

All guns: vertical ca. 285 yards, horizontal 250 or 350 yards

(Note that the vertical sightline crossing point for the P-47 is for the rising branch of the trajectory while the falling branch is far beyond 500 yards and not even indicated in the diagram.)

For the P-38:

20 mm cannon: vertical ca. 250 yards, on the centreline
upper 12.7 mm M2: 200 yards, horizontal unknown (parallel?)
lower 12.7 mm M2: ca. 225 yards, horizontal unknown (parallel?)

(Again, this is for the rising brach of the trajectory.)

Regards,

Henning (HoHun)

 

[Achtungbaby]

Great information!! Thanks. Is the diagram you mention available on the internet somewhere?

 

[GADGET]

You might find this information on this very same forum by dowloading the Mustang, Thunderbolt, Messer and Fockewulf manuals. The Spitfire V irregular zone armonization pattern is particulary interesting and can be found in the Spirfire V Manual published by the RAF Museum.

Please take it also in account that each unit, and even each pilot, had their preferences when it comes to boresighting the guns of their particular aircraft, showing then notable differences.

 

[KrazyKraut]

Here's a table showing the arrangement for the earlier Fw-190 As btw:

 

[Achtungbaby]

Thanks for everyone's input I am now finding the information I was looking for...