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Lead-Computing Gunsights  
User currently offlineBlackbird From , joined Dec 1969, posts, RR:
Posted (6 years 1 month 6 days 4 hours ago) and read 8570 times:

When was the first Lead-Computing Gunsights developed and fielded?

Blackbird

20 replies: All unread, jump to last
 
User currently offlineMCIGuy From United States of America, joined Mar 2006, 1936 posts, RR: 0
Reply 1, posted (6 years 1 month 6 days 3 hours ago) and read 8543 times:

AFAIK, the MiG-29, but I could be wrong.


Airliners.net Moderator Team
User currently offlineBlackbird From , joined Dec 1969, posts, RR:
Reply 2, posted (6 years 1 month 6 days 2 hours ago) and read 8540 times:

MCI Guy,

How accurate does a lead-computing gunsight work? Does it improve pilot shooting accuracy to like 100% or just higher than without it?

Blackbird


User currently offlineBoeing4ever From , joined Dec 1969, posts, RR:
Reply 3, posted (6 years 1 month 5 days 23 hours ago) and read 8499 times:



Quoting MCIGuy (Reply 1):
AFAIK, the MiG-29, but I could be wrong.

You are.  Wink Lead computing gunsights were first developed by the British during the Second World War. The P-51D had one. Not sure if that's the first type fitted with such a device.

 airplane B4e-Forever New Frontiers airplane 


User currently offlineBlackbird From , joined Dec 1969, posts, RR:
Reply 4, posted (6 years 1 month 5 days 23 hours ago) and read 8493 times:

Boeing4ever,

How did the device manage to compute the enemy aircraft's speed into the equation without a radar?


Blackbird


User currently offlineBoeing4ever From , joined Dec 1969, posts, RR:
Reply 5, posted (6 years 1 month 5 days 23 hours ago) and read 8492 times:



Quoting Blackbird (Reply 4):
How did the device manage to compute the enemy aircraft's speed into the equation without a radar?

Simple...they didn't.

http://forum.axishistory.com/viewtop...d=51c60b7d43f1923c2bb9a94c598a6ff1

Google "gyroscopic gun sights".

http://www.429sqn.ca/acmgs.htm

 airplane B4e-Forever New Frontiers airplane 


User currently offlineBlackbird From , joined Dec 1969, posts, RR:
Reply 6, posted (6 years 1 month 5 days 22 hours ago) and read 8488 times:

Boeing4ever,

Quote:
Simple...they didn't.

Then how did the gunsight 'know' how far to lead the target?


Blackbird


User currently offlineBoeing4ever From , joined Dec 1969, posts, RR:
Reply 7, posted (6 years 1 month 5 days 22 hours ago) and read 8486 times:



Quoting Blackbird (Reply 6):
Then how did the gunsight 'know' how far to lead the target?

This is a simplistic explanation, and geared I believe towards the P-51's system, but the pilot would input the range and with a gyroscope, a moving reticule would move to the position on the sight where the aircraft's munitions would arc based on the aircraft's turn rate, speed, etc. The gunsight did not work by "locking" onto a bandit like modern radar guided ones do, but rather by finding the true location of where the firepower would arc. A skilled pilot would try to place this moving reticule on the target with his fixed one usually "ahead" of the moving one in a turning fight.

If anyone else wants to make corrections or add more detail, feel free.

 airplane B4e-Forever New Frontiers airplane 


User currently offlineBlackbird From , joined Dec 1969, posts, RR:
Reply 8, posted (6 years 1 month 5 days 20 hours ago) and read 8460 times:

Modern day lead-computing gunsights are much more advanced I would assume...

Blackbird


User currently offlineF4wso From United States of America, joined Oct 2003, 974 posts, RR: 11
Reply 9, posted (6 years 1 month 5 days 9 hours ago) and read 8381 times:

The distance of the WWII fighters was set to the convergence of the wing's guns. G loading on the gyro determined how much lead to deflect the reticle. The F-86 had a range only radar to determine the distance. The F-4E had a Lead Computing Optical Sight System (LCOSS) that could be used either in an air to air or air to ground mode. After retrofitting with the ring laser gyro inertial system, the system could be updated by placing the LCOSS pipper on a landmark with known coordinates.

Gary
Cottage Grove, MN, USA



Seeking an honest week's pay for an honest day's work
User currently offlineDeltaGuy From , joined Dec 1969, posts, RR:
Reply 10, posted (6 years 1 month 5 days 8 hours ago) and read 8368 times:



Quoting Johns624 (Reply 9):
Blackbird, why don't you hop on a plane to DAY and go to the Air Force Museum at WPAFB. Take your Visa card and go crazy in the bookshop. Buy the entire collection and then you won't have to keep asking people all these esoteric and trivial questions...

Don't forget a trip to PNS and the $70 roundtrip cab fare to the Naval Air Museum...between the two museum's book stashes, you'd be set. I mean, it's alot funner to argue against a book than it is an expert, right?  Wink

I say we set up a beer fund to get this done.  rotfl 

DeltaGuy


User currently offlineMCIGuy From United States of America, joined Mar 2006, 1936 posts, RR: 0
Reply 11, posted (6 years 1 month 4 days 23 hours ago) and read 8305 times:



Quoting Boeing4ever (Reply 3):
You are. Lead computing gunsights were first developed by the British during the Second World War. The P-51D had one. Not sure if that's the first type fitted with such a device.

OK, yeah, I thought OP was talking about an autocannon. The MiG-29 uses a laser range finder and IRST and automatically burps off a burst of 30mm when an adversary flies into the bullet's path. Wasn't the MiG-29 the first to have that capability?



Airliners.net Moderator Team
User currently offlineBlackbird From , joined Dec 1969, posts, RR:
Reply 12, posted (6 years 1 month 4 days 21 hours ago) and read 8282 times:

MCIGuy,

Quote:
OK, yeah, I thought OP was talking about an autocannon. The MiG-29 uses a laser range finder and IRST and automatically burps off a burst of 30mm when an adversary flies into the bullet's path. Wasn't the MiG-29 the first to have that capability?

I would assume the cannon's accuracy is pretty much 100%. My question is, is there any manual ability to fire the gun, or is it totally automatic?


Blackbird
BTW: Does the F-22 Raptor feature such an automatically-firing cannon as well, and like what I asked before, does it have any provision for manual use, or is it totally automatic?


User currently offlineMCIGuy From United States of America, joined Mar 2006, 1936 posts, RR: 0
Reply 13, posted (6 years 1 month 4 days 16 hours ago) and read 8238 times:



Quoting Blackbird (Reply 13):
I would assume the cannon's accuracy is pretty much 100%. My question is, is there any manual ability to fire the gun, or is it totally automatic?

Both, but it's 30mm so they only pack around 100 rounds because of the size and weight. Firing the gun manually could eat through the magazine in a pretty big hurry.



Airliners.net Moderator Team
User currently offlineBoeing4ever From , joined Dec 1969, posts, RR:
Reply 14, posted (6 years 1 month 4 days 13 hours ago) and read 8215 times:



Quoting MCIGuy (Reply 12):
OK, yeah, I thought OP was talking about an autocannon. The MiG-29 uses a laser range finder and IRST and automatically burps off a burst of 30mm when an adversary flies into the bullet's path. Wasn't the MiG-29 the first to have that capability?

Didn't mean to rag on you there. I only recently got wind of these sights thanks to History Channel's "Dogfights".  Smile hmmmm, interesting thing about the MiG's 30mm cannon though. Hey, I learned something new. At the risk of sounding like B747forever, thanks for sharing that one!  Smile Good question though, was the MiG-29 the first to use such a system?

 airplane B4e-Forever New Frontiers airplane 


User currently offlineBlackbird From , joined Dec 1969, posts, RR:
Reply 15, posted (6 years 1 month 4 days 5 hours ago) and read 8164 times:

Is the accuracy of that auto-cannon 100% or very close to it?

Blackbird


User currently offlineMCIGuy From United States of America, joined Mar 2006, 1936 posts, RR: 0
Reply 16, posted (6 years 1 month 4 days 5 hours ago) and read 8163 times:



Quoting Boeing4ever (Reply 14):
Didn't mean to rag on you there.

It's all good... Smile

Quoting Blackbird (Reply 15):
Is the accuracy of that auto-cannon 100% or very close to it?

AFAIK, yes.  Smile



Airliners.net Moderator Team
User currently offlineBlackbird From , joined Dec 1969, posts, RR:
Reply 17, posted (6 years 1 month 4 days 5 hours ago) and read 8159 times:

Does the F-22 have a system like this?

Blackbird


User currently offlineJabs From Portugal, joined Feb 2007, 35 posts, RR: 0
Reply 18, posted (5 years 12 months 4 days 9 hours ago) and read 7545 times:



Quote:
The K-14 Lead-computing Gunsight

During the autumn of 1944 the P-51D was cleared to use the new K-14 Lead-computing Gunsight. This revolutionary piece of equipment automatically displayed the correct angle of deflection required to hit a moving target, and was thus the answer to a many pilot’s prays. Deflection shooting was a skill many found difficult to master, irrespective of the aircraft they were flying, or the air force in which they flew.

The only alternative to good deflection shoot was to get in very close, and this method of attack brought with it its own problems, not the least of which was the danger of debris flying back from the target as soon as the pursuing pilot opened fire. Also, the stricken fighters often suddenly exploded violently if hit in the fuel tank.

Deflection shooting didn’t entirely eliminate such hazards, but significantly reduced them, and the K-14 (widely known as ‘the ace-maker’ sight in the eighth) was eventually issued to all P-51 groups. A light touch was required to use it effectively, with the pilot having to resort to the ‘ring and bed’ if his target rapidly reversed direction, as such violent maneuvering could easily cause the K-14’s temperamental gyros to ‘tumble’ as the pilot tried to follow his quarry.



The Mk II Gyro Gunsight

Early in the war it was realized that if an automatic device could be developed to indicate the pilot the correct amount of deflection to use when firing during a turning combat, this would greatly enhance the effectiveness of the fighter force. Following four years of hard work at the Royal Aircraft Establishment at Farnborough, the Mk II Gyro Gunsight went into large scale production at the end of 1943.

This device worked on the principal that if a fighter pilot followed an enemy aircraft in the turn and held his gunsight on the later, his rate of turn was proportional to the deflection angle required to hit the enemy. A gyroscope measured his rate of turn, and tilted a mirror which moves the position of the sighting graticule to show the required deflection angle. The required deflection varied with range, however, so the gunsight incorporated a simple system of optical rangefinding. Before the engagement the pilot set on the sight the approximate wingspan of the enemy aircraft. As he closed on his foe, the pilot operated a control mounted on the throttle arm which altered the diameter of the sighting graticule so that it size matched the wingspan of the enemy aircraft. Since the wingspan of the target aircraft had been set on the sight, the adjustment of the graticule ‘told’ the gunsight the range of the target. An analogue computer in the gunsight worked out the correct point ahead of the target at which the pilot should aim in order to score hits.

Once fighter pilots got used to the new sight and learned its foibles, the general accuracy of deflection shooting improved dramatically. During 1944 an analysis of 130 combats by Spitfire Mk IXs fitted with fixed-graticule sights revealed that there had been 34 kills – 26 per cent of the total. During the same period, one squadron operating the same Spitfire variant fitted with the new gunsight took part in 38 combats, scoring 19 kills – 50 per cent of total. The new gunsight virtually doubled the effectiveness of air-to-air gunnery. With the new sight, pilots reported scoring hits on evading targets at ranges as great as 600 yards, and at deflection angles of up to 50 degrees.



The Revi EZ-42/1-A1 Gyroscopic Gunsight

Designed and manufactured by Askania at Berlin-Friedenau and Carl Zeiss at Jena, the EZ-42 automatically computed the deflection angle required to hit a target when both aircraft were maneuvering. It thus gave to every fighter pilot the ability which up to that time had only been possessed by a few Experten.

The angle of lead was fixed as a product of angular velocity multiplied by the velocity of the projectile used. The angular velocity for traverse and elevation was measured two bank and turn indicators, whilst range-finding could be performed by the use of a target circle which could be adapted to the target by means of an adjuster built into the case of the sight. When approaching a target, a pilot had to ensure that he continuously twisted the range-finding button on the aircraft’s control column so that the growing target was permanently encapsulated in the dial as well as making sure that the cross-wire was contained within the target-circle on the target. The resulting derivation followed by means of a connection to a potentiometer. The precise angle of deflection was obtained within two seconds.

Accuracy could be guaranteed to within 15% of the angle of deflection in the longitudinal direction of the enemy and 10% perpendicularly




“Mustang Aces of the Eight Air Force” by Jerry Scoutts, Osprey Aircraft of the Aces Nº 1, ISBN 1-8553244-74, Osprey Publishing 1994

“Late Mark Spitfire Aces 1942-45” by Dr. Alfred Price, Osprey Aircraft of the Aces Nº 5, ISBN 185532-575-6, Osprey Publishing 1995

JV 44 – The Galland Circus” by Robert Forsyth, Classic Nº 1, ISBN 0-9526867-0-8, Classic Publications 1996

“Me 262 Volume 2” by J. Richard Smith & Eddie J. Creek, Classic Nº 4, ISBN 0-9526867-32, Classic Publications 1998



User currently offlineTheSonntag From Germany, joined Jun 2005, 3630 posts, RR: 29
Reply 19, posted (5 years 12 months 4 days 9 hours ago) and read 7538 times:

So best thing against a Mig-29 is to shoot it down before it gets close to you?  Wink

User currently offlineBlackbird From , joined Dec 1969, posts, RR:
Reply 20, posted (5 years 12 months 4 days 6 hours ago) and read 7486 times:

TheSonntag,

So it would seem!


Blackbird


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