How were Motorkanone sighted in?

[Broncazonk]

Given the effects of gravity, and the required ballistic arc necessay for fired projectiles, how were MG 151/20 motorkanone sighted in? Note the ballistic arcs illustrated in the diagrams below. The arc is achieved by elevating the cannon muzzle in the wing and/or fuselage. But you can't do that with a motorkanone, as the projectile goes straight out of the propellor hub. The muzzle cannot be elevated, and the shell began falling the instant it left the barrel. As a result, a motorkanone must have had a VERY short range.

So how did they sight them in?? That is, how were they harmonized with wing and fuselage armament?

Bronc

[Evgeny Velichko]

I hope it helps:

[Broncazonk]

That's a borescope, I think. The instrument was used to inspect the condition of the fifling inside the barrel.

Bronc

[Arado 396]

Hi Bronc

The device is a target line tester ( Ziellinienprüfer ) and gave it for many Caliber.
It is also described here ( Site 17 / 18 an 26 ):

---> http://www.avia-it.com/act/profili_d...u-87%20D-5.pdf

... here Pictures:

---> https://www.deutscheluftwaffe.de/fl-...fer-zp-5-1941/

---> https://www.kpemig.de/Transportkaste...ginal-lackiert

[Broncazonk]

Okay, a "target line tester." So that would be the equivalent to a "bore sight kit?"

That's a critical piece of information. Here then is (what I propose was) the process.

1) The aircraft was jacked up,

2) A target was walked out to the desired range, say 300-meters,

3) The target line tester/bore sight kit was installed,

4) The target was moved left or right until it came into view of the bore sight kit.

5) The aircraft was jacket up or down until the bore sight kit was zeroed on the target.

6) The bore of the cannon was now "on target."

7) The Revi gunsight was then adjusted to zero on the target.

The motorkanone was thus sighted in. This means the aircraft was not level in flight when firing. The nose had to be up--elevated--to provide the necessary ballistic arc.

Anyone?

Bronc

[Graham Boak]

Allowance for the ballistic arc is an inevitable part of all airborne guns, not just central cannon. They are generally regarded as more accurate than wing-mounted guns because they are unaffected by flight loads that twist the wings.

[Don Pearson]

Also shown in this well-known photo

Don