A gunnery question.....

corsair166b · **Posted:** Thu Oct 22, 2009 10:22 pm

Always heard about fighter pilots talking about how they pulled 'a full deflection shot' on an enemy fighter or some such phrase, never quite understood what those terms meant....maybe someone could lay it out for me....30 some years of studying warbirds and WWII planes and the thought occured to me today driving home from work I have no idea to this day what a 'full deflection shot' or 'partial deflection shot' or whatever means......

Mark

JDK · **Posted:** Thu Oct 22, 2009 10:25 pm

Deflection shooting is simply shooting at where the target will be when the bullet / shell arrives, not where it is when you pull the trigger.

corsair166b · **Posted:** Thu Oct 22, 2009 10:54 pm

So basically it's leading a target.....so why call it 'deflection' and confuse, why not just call it leading.....I always thought a 'full deflection shot' was shooting at another plane from immediately behind it and the bullets would 'deflect' off of the wings and fuselage because of the curved surfaces of the plane being shot at....and that was the impression in my younger years....later I on knew it was'nt the case, but I still did'nt know what the term meant...

anyway....

Mark

warbird1 · **Joined:** Fri Sep 21, 2007 6:25 pm **Posts:** 2760

JDK is correct. "Deflection" shooting simply means shooting the bullets in front of the target to compensate for the relative motion of it in relation to the shooting platform. In other words, you must "lead" the target. It has absolutely nothing to do with bullets physically bouncing or richocheting off of anything. That is a HUGE misperception by a lot of people. Sometime around the Korean war, that term quit being used so much. These days, it's called "lead pursuit". In other words, you must lead the bullets in front of the target, so the target will "run" into the bullet stream.

I'm sure Randy will chime in here fairly quickly, and give a detailed analysis on the differences in lead, lag, and pure pursuit. All of these are modern day terms.

Punisher05 · **Posted:** Fri Oct 23, 2009 2:00 am

IIRC, a "full deflection shot" meant making a shot from an extreme angle...like 90 degrees off the target's line of travel.

If that's confusing, this may help: a 0-degree shot would be directly behind or directly ahead of the target (from 12 or 6 o-clock). 0-degree shots do not require any (or as much) lead. A 45-degree shot would be roughly at the target's 2, 5, 7, or 10 o-clock, and more lead (and skill) would be required.

The 90-degree shot would be made from 3 or 9 o-clock, and requires the most skill to hit. It's another reason that a shot from directly behind was preferred!

JDK · **Posted:** Fri Oct 23, 2009 2:27 am

corsair166b wrote:

So basically it's leading a target.....so why call it 'deflection' and confuse, why not just call it leading...

Interesting question. My guess would be that 'leading' has multiple meanings and usage, while in military aviation, or shooting, deflection has one. In that context, therefore, you can argue it's more precise.
HTH

RAMC181 · **Posted:** Fri Oct 23, 2009 7:06 am

JDK wrote:

corsair166b wrote:

So basically it's leading a target.....so why call it 'deflection' and confuse, why not just call it leading...

Interesting question. My guess would be that 'leading' has multiple meanings and usage, while in military aviation, or shooting, deflection has one. In that context, therefore, you can argue it's more precise.
HTH

For bomber gunners the drill was to always add deflection toward the tail of your own aircraft.
Counter-intuitive I know, but the forward momentum of the bomber was carried over to the projectiles and they would seem to catch-up with the target.
The example used in training at the time was the news-boy on his bike, trying to land a newspaper on a porch while cycling past.

All the best,
PB

K5DH · **Posted:** Fri Oct 23, 2009 7:26 am

Don't they also call that "Kentucky windage"?

Cheers,

Dudley Henriques · **Posted:** Fri Oct 23, 2009 9:30 am

corsair166b wrote:

Always heard about fighter pilots talking about how they pulled 'a full deflection shot' on an enemy fighter or some such phrase, never quite understood what those terms meant....maybe someone could lay it out for me....30 some years of studying warbirds and WWII planes and the thought occured to me today driving home from work I have no idea to this day what a 'full deflection shot' or 'partial deflection shot' or whatever means......

Mark

Generally speaking, a deflection shot requires lead correction in any single or combination of the 3 dimensions involved in a tracking solution and can be defined as any solution involving an angle off the target other than 0 coupled with a gravity drop correction. Technically you can add several additional factors to the solution equation such as velocity jump, trajectory shift, time of flight of the bullet stream, g on the attacker's aircraft, closure rate, and a few other tech goodies, and you are either a pilot in a Spad attempting to do all this in your brain or a pilot in a modern fighter doing it with the help of a fire control system.
Either way, a deflection shot requires a lead correction.
This was done in "the old days" by the pilot and is accomplished in today's modern fire control systems by computer coupled with a lead computing gunsight.
The fire control solution involves pursuit geometry interfaced into a platform relationship based on lead computed data fed into the computer in real time as the attacker attempts to solve the factors involved.
The higher the deflection angle, the more work has to be done to solve the problem.
Perhaps some of the greatest examples in modern times of good deflection shooting was accomplished by the Israeli fighter pilots during the 6 day war when they recorded some of the finest snap shooting at high angle off ever seen on film.

Bottom line is that unless you're sitting in the saddle at 6 o'clock hosing somebody, you're solving for deflection when attacking an airborne target with gunfire.

I'm sure Randy Haskin can and will add to this basic explanation as he deals with it every day.
Dudley Henriques

the330thbg · **Joined:** Wed Nov 14, 2007 3:06 pm **Posts:** 2713

old kentucky windage!

Holedigger · **Posted:** Fri Oct 23, 2009 1:04 pm

To simulate Gunnery training. Get in the back of a Pickup truck with a 12 gauge and go dove hunting.
Rules
1. Must drive at least 80 mph.
2. Doves must be flying to shoot at
3. No shooting lawyers in the face

Pogmusic · **Posted:** Fri Oct 23, 2009 1:37 pm

When my dad trained as a gunner in WWII, the first shooting they did was at a skeet range!

Holedigger · **Posted:** Fri Oct 23, 2009 1:47 pm

Here is a fun link on aerial gunnery training, which DID include shotgun from the back of a moving truck! Lots of interesting pics
http://browningmgs.com/AirGunnery/11_Training.htm

michaelharadon · **Posted:** Fri Oct 23, 2009 9:14 pm

Holedigger wrote:

Here is a fun link on aerial gunnery training, which DID include shotgun from the back of a moving truck! Lots of interesting pics
http://browningmgs.com/AirGunnery/11_Training.htm

Did Axis gunners have such extensive training?

John Dupre · **Posted:** Fri Oct 23, 2009 9:24 pm

I have read that for the bomber gunners tracking an incoming fighter on a "pursuit curve" at certain angles the correct "deflection" was to actually aim behind the attacking fighter! There was a particular RAF officer who really understood the physics involved (not only for that problem but for all of aerial gunnery) and after he toured and instructed throughout the 8th AF the bombers claims went up.

Warbird Information Exchange

A gunnery question.....

Who is online