Reason for offset German sights?

[KOM.Nausicaa]

Sources, in books yes. Maybe you can find something on the web.

Why didn't other airforces think of this? Frankly I don't know. If you ask me, it's one of those oddities of german engineering (I am german myself)....this is not the only one btw. They had also other stuff in the cockpit noone esle had that way.

[Codex]

OK I may have found an explanation in the most unlikely place, a patent for the target reticle on telescopic sights believe it or not, but I am still not a 100% convinced this why the sights are offset.

Source: http://www.wipo.int/pctdb/en/wo.jsp?...7&DISPLAY=DESC

GYROSCOPIC EFFECT: A spinning projectile from a rifled barrel is, in effect, a free gyroscope. When subjected to a twist or torque, it tends to rotate about an axis perpendicular to the axis about which the torque is exerted. The front wheel of a bicycle is a good illustration of this phenomenon. If the bicycle is tipped to the right when rolling forward, the front wheel resists tipping and instead its axle rotates to the right, turning the bicycle to the right.
While following its path, which is constantly curving downward, a projectile is subject to a force (air drag) on its nose from underneath, causing a twist or torque. If its spin is clockwise, this upward torque causes the projectile's nose to rotate and offset slightly to the right (like the bicycle wheel) as seen from the rear. This offset causes air drag to act unevenly and to push the projectile slightly to the right.
The effect of gyroscopic drift is difficult to analyze precisely because many variables are involved. Drift tables, which have been determined mainly from well-controlled army and navy tests, indicate that gyroscopic drift is roughly double that of Coriolis drift, and thus is also negligible for most purposes. It is interesting to note that with counterclockwise or left-twist barrel rifling, gyroscopic drift is to the left in the northern- hemisphere and more than cancels the effects of coriolis drift.

[Von_G]

Hmm...
That's interesting but it seems to be describing the offset of the projectiles nose, rather than the sight.

It seems the right eye thing, and keeping the view of the nose open are the best potential answers, although frankly neither one seems like an especially strong reason.
Maybe as KOM.nausicaa says, the germans just feel a need to be different!

Originally Posted by KOM.Nausicaa

...If you ask me, it's one of those oddities of german engineering (I am german myself)....this is not the only one btw. They had also other stuff in the cockpit noone esle had that way.

[deadmeat313]

I thought the pilot had the option to mount the sight on the left if that was his dominant eye?

[KOM.Nausicaa]

Hello von G,

still not convinced yet I see

To understand why the gunsight can be offset to one side it is important to understand reflector sights first. There are several good articles on the web about this.

About the REVI 16, there is a good article here on the german site Luftarchiv.
http://www.luftarchiv.de/index.htm?h...te/optisch.htm

"Das Reflexvisier ist ein optisches Visiergerät für starr in Flugzeuge eingebaute MG's, kann aber auch auf einem fest mit dem beweglichen MG verbundenen Aufsatz eingesetzt werden. Das Bild der Zielmarke wird durch ein Projektionssystem in der Zielebene abgebildet und wir somit gleichzeitig mit dem Ziel ohne Akkomodation scharf gesehen; kleine Bewegungen des Auges stören nicht, solange das Auge in dem die Zielmarke abbildenden Strahlenbündel sich befindet. Die Zielmarke selbst ist leuchtend; die Helligkeit kann der des Zieles angepasst werden. Die Lage und der Bildwinkel der aus einem leuchtenden Kreis mit eingesetzten Zielstacheln bestehenden Zielmarke sind unabhängig von dem Augenort: seitliche Verschiebungen des Auges oder eine zu große Entfernung vom Zielgerät bewirken lediglich ein abschneiden des Kreises, der die Größe der Vorhaltung angibt"


I will translate the last sentence: "The position and the angle of view of the target marker representing a illuminated circle with integrated target pointers are independent of the position of the eyes: lateral changements of the eye-position, or a too great distance towards the gunsight will only cut off the circle..."

You also have to understand that IL2 (as many other flightsims) gives a poor representation of how close the head of the pilot towards the instrument panel actually was, and how tiny the cockpit was:
http://home.arcor.de/nsu-binder/nsu-...w190/fw190.htm

Considering how the reflective gunsight REVI (Reflektions Visier) works, the head of the pilot was always inside the cone of projection of the gunsight. It was thus very easy, by leaning forward, turning the head a little to the right, or closing the left eye, to get a full view through the REVI. :

http://old.messerschmitt-bf109.de/ph...pit-bf109b.php

You can see in the upper link the construction plan for the instrument panel. The gunsight cut-out isnt that far offset as you might think. You can also see that it's position is already foreseen. There is thus no possibility to set it to the left, as far as I am aware.

Hope this helps

[Codex]

Originally Posted by Von_G

Hmm...
That's interesting but it seems to be describing the offset of the projectiles nose, rather than the sight.

It seems the right eye thing, and keeping the view of the nose open are the best potential answers, although frankly neither one seems like an especially strong reason.
Maybe as KOM.nausicaa says, the germans just feel a need to be different!

Yes it describes the drag effect on a projectile's nose, but with it spinning through the air in a clockwise direction this effect will cause the projectile to drift to the right of its intended flight path, hence the need to have the gun sight slightly to the right in the pit.

But the thing that doesn't convince me of this idea being reason for offsetting the gun sight, is that I think the effect of this drift on weapons with a convergence of 300m or even 500m would be very minimal, and also the fact that allied planes had the sight in the centre.

I'm leaning towards KOM.Nausicaa descriptions.

[Von_G]

Originally Posted by KOM.Nausicaa

...I will translate the last sentence: "The position and the angle of view of the target marker representing a illuminated circle with integrated target pointers are independent of the position of the eyes: lateral changements of the eye-position, or a too great distance towards the gunsight will only cut off the circle..."

You also have to understand that IL2 (as many other flightsims) gives a poor representation of how close the head of the pilot towards the instrument panel actually was, and how tiny the cockpit was:
http://home.arcor.de/nsu-binder/nsu-...w190/fw190.htm

Considering how the reflective gunsight REVI (Reflektions Visier) works, the head of the pilot was always inside the cone of projection of the gunsight. It was thus very easy, by leaning forward, turning the head a little to the right, or closing the left eye, to get a full view through the REVI...
Hope this helps

Yup, KOM, that is a big help. Its pretty clear that the offset is entirely functional, although I still dont see it as giving any significant advantages either. If it had, all other manufacturers would have copied this innovation.

Love your pics of the 190 pit though. Is that you, and which museum is that?
Would love a chance to sit in a FW myself!

[KOM.Nausicaa]

No it isnt me, just something I found on the web.
It is the Aircraft Museum Hannover Laatzen in Germany.