Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: lyric1 on October 22, 2011, 06:41:17 PM
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I am guessing it is for sighting the guns convergence or something along those lines.
Any one know exactly what this guy is doing with that tool?
(http://i1002.photobucket.com/albums/af142/barneybolac/Bundesarchiv_Bild_101I-390-1220-19_Russland_Flugzeug_Me_109_des_JG_54_Wartung.jpg)
(http://i1002.photobucket.com/albums/af142/barneybolac/Bundesarchiv_Bild_101I-390-1220-20_Russland_Flugzeug_Me_109_des_JG_54_Wartung.jpg)
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It's a boresight. Position the plane so that the gun sight is centered on a target at a given distance, then use the boresight to see where the bullet will actually strike. Then adjust until they match. Basically.
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could we please get that skin :neener:
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I dont think they could adjust the convergence on the motorcannon,likely they were making sure the bore was aligned with the blast tube. Would be a good thing to have a round hit the blast tube on the way out!
:salute
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I dont think they could adjust the convergence on the motorcannon,likely they were making sure the bore was aligned with the blast tube. Would be a good thing to have a round hit the blast tube on the way out!
You don't think they adjusted the site in the cockpit to match up with the strike point of the cannon?
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Just my 2 cents, but I believe he was lining up the motorcannon, then when on target he will adjust the other guns to meet at convergence... :old:
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Endoscope.
Prostate exam.
:bolt:
wrongway
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You don't think they adjusted the site in the cockpit to match up with the strike point of the cannon?
IIRC,the motor cannon was set to converge at 400 mtrs. whether or not the sight was adjusted or not I cant say for sure.
I've seen that picture before and always thought they were checking alignment with the blast tube.
:salute
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It's a "make work" tool that was designed to give the officers something to look busy with. :bolt:
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It's called a Muzzle Boresite Device, and it is used to ensure that all weapon systems are adjusted to hit the same point of aim.
The same system is still used today for armored vehicles...like the M1 tank. Each caliber of weapon has it's own Boresite Device, and each weapon gets boresited separately as part of the system.
Here is a link to a portion of the manual that describes the process for an M1 Tank: http://www.globalsecurity.org/military/library/policy/army/fm/17-12-7/ch11.htm (http://www.globalsecurity.org/military/library/policy/army/fm/17-12-7/ch11.htm)
The officer in the the picture is probably the pilot of that aircraft, I know I wouldn't trust someone else to get the boresite correct for my ride...not if MY life was depending on it.
First a reference target panel is placed at a known distance from the weapon, the MBD is inserted into the muzzle of the weapon, and while looking thru the device at the target, the commander or pilot directs the other crew members to make adjustments to the weapon so that the muzzle end of the weapon is aimed at a known point on the boresite target panel. After each of the muzzles is properly aimed at the reference target, the sight or sights in the turret or cockpit are adjusted so that it or they are also looking at the same point of aim. Each individual gun or weapon must be adjusted separately without disturbing the others.
Corrections are made by making adjustments to the weapon mounting cradle at the breech end of the weapon, while ensuring that the boresite device remains pointed precisely at the target aiming point. Making adjustments is a finicky process. The jack stands in the picture are used to maintain the aircraft in a normal level-flight attitude in the pitch, roll, and yaw axes. An error in cant (roll axis) will throw off the point of impact in both elevation and deflection.
After adjusting all the weapons to the same point of aim, the sight or sights are adjusted or "referred" to the same point of aim. The final step is to fire each of the weapons to confirm that the point of aim is in fact the same as the point of impact. Since machine guns are an "area fire" weapon, some dispersion is normal and will be expected. As long as all rounds fired land within the expected dispersion area, the weapon is considered "boresited", and the data used to make corrections will be recorded for future reference and maintenance purposes.
CptA
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It's called a Muzzle Boresite Device, and it is used to ensure that all weapon systems are adjusted to hit the same point of aim.
The same system is still used today for armored vehicles...like the M1 tank. Each caliber of weapon has it's own Boresite Device, and each weapon gets boresited separately as part of the system.
Here is a link to a portion of the manual that describes the process for an M1 Tank: http://www.globalsecurity.org/military/library/policy/army/fm/17-12-7/ch11.htm (http://www.globalsecurity.org/military/library/policy/army/fm/17-12-7/ch11.htm)
The officer in the the picture is probably the pilot of that aircraft, I know I wouldn't trust someone else to get the boresite correct for my ride...not if MY life was depending on it.
First a reference target panel is placed at a known distance from the weapon, the MBD is inserted into the muzzle of the weapon, and while looking thru the device at the target, the commander or pilot directs the other crew members to make adjustments to the weapon so that the muzzle end of the weapon is aimed at a known point on the boresite target panel. After each of the muzzles is properly aimed at the reference target, the sight or sights in the turret or cockpit are adjusted so that it or they are also looking at the same point of aim. Each individual gun or weapon must be adjusted separately without disturbing the others.
Corrections are made by making adjustments to the weapon mounting cradle at the breech end of the weapon, while ensuring that the boresite device remains pointed precisely at the target aiming point. Making adjustments is a finicky process. The jack stands in the picture are used to maintain the aircraft in a normal level-flight attitude in the pitch, roll, and yaw axes. An error in cant (roll axis) will throw off the point of impact in both elevation and deflection.
After adjusting all the weapons to the same point of aim, the sight or sights are adjusted or "referred" to the same point of aim. The final step is to fire each of the weapons to confirm that the point of aim is in fact the same as the point of impact. Since machine guns are an "area fire" weapon, some dispersion is normal and will be expected. As long as all rounds fired land within the expected dispersion area, the weapon is considered "boresited", and the data used to make corrections will be recorded for future reference and maintenance purposes.
CptA
Awesome and informative. :aok Thank you CptA. :salute
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If I added up all the hours of my life playing with a boresight for an M60A3 or M1A1...
When done properly you can kill a gnat at 1750m no problems. When it is off you go insane.
Boo
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Can anyone make out that coat of arms on the fuselage, next to the mechanic's knee?
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Can anyone make out that coat of arms on the fuselage, next to the mechanic's knee?
II/JG 54
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Can anyone make out that coat of arms on the fuselage, next to the mechanic's knee?
II/JG54 (http://i241.photobucket.com/albums/ff252/DropkickYankees/Jg54Panther.png)
Although the yellow would would be white at the time of that photo.
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Y'all are good.
August '41 - I take it that's an F?
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you would be correct.
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CptA spoken like a true tanker or Master Gunner.
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Thx, I spent 22 of my 31 years of service on tanks.
I started out on M48A5s, moved up to M60s, then M60A1s, M60A3s (my favorite from a Commander/Gunner perspective), and finally M1s and M1IPs.
After that it was all staff time at Bn, Bde, and Div level.
A good Boresite, Sync, and Screening has always been the key to an effective trip downrange on the Tank Tables.
Like any well-drilled task it gets to be second nature, but you have to be carefull to prevent your crew from getting lazy and taking shortcuts...thats what manuals (and good NCOs) are for.
Steel on Target!
CptA
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CptA I started in M60A3 and ended in M1A1s was my BN master gunner and shot 995 on tank table 8 was a great day for my crew. Oh never ever do an MRS update you will never hit anything, iv been out 10 years now and I could still bore sight a tank.
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CptA, he's not a peelot. They had gull wing insignia on collars.
More than likely an Armament Specialist.
:cheers: Oz
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could we please get that skin :neener:
er.... okay.....
(http://www.netaces.org/skins/109f4/skin3.jpg)
(http://www.netaces.org/skins/109f4/skin7.jpg)
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could we please get that skin :neener:
er.... okay.....
(http://www.netaces.org/skins/109f4/skin3.jpg)
(http://www.netaces.org/skins/109f4/skin7.jpg)
I do believe that is a "Wish Granted". :D
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I do believe that is a "Wish Granted". :D
:lol
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Motorkanon were locked into the DB60X/Jumo-213E and fired level to the engine airscrew shaft line through the hollow airscrew shaft. Otherwise your round would either explode or go flying off in any direction but at the target.
The Reflexvisior gunsight was adjusted so your line of sight (visier linie) angled down over the nose of the 109 and intersected 417cm drop at 700M for a 15mm/20mm canon and 430cm drop at 500M for a 30mm canon. Not the cannon angled inside of the engine to make the round drop center on the gunsight or target. The hood MG and gondola guns could be adjusted for convergence and point of impact patterning. Everything was adjusted to give a rough 30-40cm high area of patterning between 200 and 300 meters that followed loosely the fixed trajectory of the motorkanon.
I will assume with the Ta152-H the Revi gunsight line was adjusted down with the MK108 trajectory like in the 109 family while the two wing root Mg151/20 were adjusted to pattern with it between 200M and 300M similare to the gondola patterning in 109's.
MG151/20 Motorkanon
28cm drop at 250M
210cm drop at 400M
Drops off drasticly after 400M. 300+cm(10ft) by 500M
MK108 30mm Motorkanon
120cm drop at 250M
338cm drop at 400M
Drops of really drasticly after 400M. 550+cm(18ft) by 500M
Russian autocanon were locked down between the cylanders in the Yak family and so was the HS.404 moteur-canon in the French Dewoitine D.520.
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Great post CptA :aok, very informative
:salute
BigRat
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Bustr... 30mm is barely more than an inch. The exit of the blast tube is at least 3 inches. You can have a lot of leeway regarding convergence with that kind of free space. It would not have hit anything unless you moved it way out of standard alignment.
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The 109 armerors manuals say the MG151/20 and MK108 are "locked" parallel to the shaft. All of the barrel adaptors make sure the barrel is centered into the shaft and locked down with four bolts. That sighting device is so the person sighting from the barrel can see the impact diagram and round patterning and note the patterning of the motorkannon, MG and gondola (if mounted) in refrence to standardised patterns for either 50 meter or 100 meter firing ranges. At those ranges the (visier linie) line of sight for the Refelxvisior is adjusted so the piper center lines up at a specific distance below the IP of the motorkanon for each cannon type.
The blast tube or hollow airscrew tube is that large of a diameter because the high speed spin induced into the mine rounds to unlock the fuse can cause random fliers. I seem to remember some of the early MK108 testing with G6 at Rechlin had a problem with the mine rounds hitting the inside of the tube. That could be why they changed fuse types from the AZ 1587 standard ACK-ACK fuze with an assymetrical safety to the ZZ 1589 with six symetrical ball berings and self detonation after traveling 700-1000M.
Find any Bf109 manual on the internet and translate the armerors section for mounting the motorkanon. They all say it's locked in and fires straight through the hollow airscrew shaft. In the back of the manuals you will find the impact forms that the sighting device looks at from the perspective of the primary wheapon on the Bf109. You can find pictures of the russian cannons bolted down to the top of the block firing through the reduction gearing and the same with the Dewoitine D.520's engine.
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bustr is right, the motor cannons of all of the Bf/Me109s were fixed.
(http://img375.imageshack.us/img375/3166/daimlerbenzdb601n.jpg)
(http://img811.imageshack.us/img811/458/j28k.jpg)
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The 109 armerors manuals say the MG151/20 and MK108 are "locked" parallel to the shaft. All of the barrel adaptors make sure the barrel is centered into the shaft and locked down with four bolts. That sighting device is so the person sighting from the barrel can see the impact diagram and round patterning and note the patterning of the motorkannon, MG and gondola (if mounted) in refrence to standardised patterns for either 50 meter or 100 meter firing ranges. At those ranges the (visier linie) line of sight for the Refelxvisior is adjusted so the piper center lines up at a specific distance below the IP of the motorkanon for each cannon type.
The blast tube or hollow airscrew tube is that large of a diameter because the high speed spin induced into the mine rounds to unlock the fuse can cause random fliers. I seem to remember some of the early MK108 testing with G6 at Rechlin had a problem with the mine rounds hitting the inside of the tube. That could be why they changed fuse types from the AZ 1587 standard ACK-ACK fuze with an assymetrical safety to the ZZ 1589 with six symetrical ball berings and self detonation after traveling 700-1000M.
Find any Bf109 manual on the internet and translate the armerors section for mounting the motorkanon. They all say it's locked in and fires straight through the hollow airscrew shaft. In the back of the manuals you will find the impact forms that the sighting device looks at from the perspective of the primary wheapon on the Bf109. You can find pictures of the russian cannons bolted down to the top of the block firing through the reduction gearing and the same with the Dewoitine D.520's engine.
I wasn't exactly refuting "it was locked" just "it would hit the tube wall if so" -- there's enough leeway was my point. Actual practice is another matter.
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The photo is labeled "August 1941" on the image, and the filename includes "Russland Flugzeug Me 109 des JG 54 Wartung" or "Russia Airplane Me 109 of JG 54 Maintenance".
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You don't think they adjusted the site in the cockpit to match up with the strike point of the cannon?
After reading Bustr's post it's evidently so,I knew the cannon was fixed/no adjustment but wasnt sure whether or not the sight was adjusted to match the cannon or if it was predetermined at the factory.
The blast tube is 55 mm inside dia. which is roughly 2 inches plenty of room for a 20mm at just over 3/4 of an inch but a 30mm is almost 1 and1/4 inches and then you have the outside dia. of the barrel so that leaves little room for error. As Bustr also said,they had issues with "fliers" striking the tube,with the short barrel on the Mk108 I would think that would be of great consern as opposed to the longer 20mm barrel.
:salute
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The Refelxvisier gunsight was adjusted to center at a point on a diagram at 50M or 100M. The ReviC/12 C has an internal screw that tilts the refelctor plate. The Revi16b has an internal screw to tilt a mirror. The adjustment was about 3 degrees. The large diameter of the airscrew shaft is to account for random flyers and other known issues that will cause an explosive round to fly off center.
The gun system and Revi sight line is keyed off the Motorkanon because its fixed in place. Thats why in the gunnery diagrams the visier linie line is also shown and what its drop in cm should be at each distance relative to the motorkanon.
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It's called a Muzzle Boresite Device, and it is used to ensure that all weapon systems are adjusted to hit the same point of aim.
The same system is still used today for armored vehicles...like the M1 tank. Each caliber of weapon has it's own Boresite Device, and each weapon gets boresited separately as part of the system.
Here is a link to a portion of the manual that describes the process for an M1 Tank: http://www.globalsecurity.org/military/library/policy/army/fm/17-12-7/ch11.htm (http://www.globalsecurity.org/military/library/policy/army/fm/17-12-7/ch11.htm)
CptA
YES! Like my laser rifle bore-sight tool, but with optics. This is why I said logically, I believe the center barrel had very little if any adjustment, & that the outer guns were converged to intersect the bore gun. How else could you adjust the bore gun without adjusting the motor mounts...? this bore-sight was to align the target paper in position for to then align the other guns. :salute
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Notice in the Bf109G pictures the triangle that represents the (Visier Linie) or the adjusted line of sight for the Revi gunsight. It is set to angle down to a negative value below the aircraft center line at 400M because of the fixed Motorkanon. The Bf109E is set level to the horizon and the guns are adjusted to fire up to intersect it than drop back down to it by 400M.
Note: In the 109G diagram the center for the Revi is 74.5cm above the centerline of the Motorkanon angling down to 5cm above that line at 100m.
Bf109G 5/6 Armeors convergence diagrams.
Impact Points and Visier Linie Points.
(http://img707.imageshack.us/img707/6766/bf109garm.gif)
Ballistics and Visier Linie.
(http://img849.imageshack.us/img849/5625/bf109garm2.gif)
North Africa Bf109E Convergence adjustments.
Firing the wing guns at 50m.
(http://img810.imageshack.us/img810/8255/me109target2.jpg)
Results on convergence diagram.
(http://img21.imageshack.us/img21/4708/me109target.jpg)
Armerors Adjustment Page.
(http://img5.imageshack.us/img5/2253/me109armdiag2.gif) (http://imageshack.us/photo/my-images/5/me109armdiag2.gif/)
Ballistics and Visier Linie.
(http://img200.imageshack.us/img200/9339/me109armdiag.gif) (http://imageshack.us/photo/my-images/200/me109armdiag.gif/)
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Great pictures and diagrams bustr :salute
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Great pictures and diagrams bustr :salute
Yep :aok
Did not think this thread was going to this interesting.
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Yep :aok
Did not think this thread was going to this interesting.
Oh c'mon Lyric,you post a pic of a German with a dewhicky looking into a thingamabob and you dont think it will be interesting???? :devil
Bustr,thats a great pic of the ammour's target! :aok you can clearly see the dispersion pattern,looks alot like it does ingame!!
:salute