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The Air Corps ordered the Norden for its at Maxwell Field, Ala., began developing a Norden M-7 bombsight in 1942, but over. As the lead B-17G drops its bombs, following Flying Fortresses of the 324th Squadron, 91st Bomb Group, drop their ordnance on cue. 32 A V I A T I O N H I S T O RY. MARCH 2014 Norden M-9 Bombsight. The Norden Bombsight was chosen to lead the way in daylight precision bombing by the United States Army Air Forces in World War II. The heavy bombers had a crew of ten men, and nine of them risked their lives in combat to get the bombardier and this bombsight over the target. Now, you can own a piece of that history, fully restored to the same. The RAF was working on such a design, the Automatic Bomb Sight, but development was slow and it had not been accepted for use when the war started. Learning of a similar design developed by the US Navy, the Air Ministry began extensive negotiations in an effort to gain a production licence for this Norden bombsight. One of a series of classified films made for training by the Army Air Forces during WWII, this film about the Norden Bombsight focuses on the operation of th. 14 pages; PDF (.pdf) Original item: Book; 8.5 x 11 inches Viewed: 577 times. Section 6: M-Series Bombsight M-Series Bombsight; Norden Bombsight; Preflight Procedure; Field Inspection and Care; Cold and Hot Weather Operation; Bombing with Defective Bombsight; Glide Bombing Attachment; X-1 Reflex Sight; 7.4Mb 30 pages; PDF (.pdf).

SPERRY S-1

The Sperry S-1 bombsight was designed by Elmer Sperry, Carl Norden's former employer. It had several distinctions from the Norden, and some advantages. The Sperry gyroscopes spun at 24,000 rpm, compared to the Norden gyros which ran at approximately 8,000 rpm. This higher rate of rotation overcame the tendency to precess, so there was no leveling mechanism needed, or a requirement for leveling bubbles. In addition, the gyros ran off of induction rather than brushes; the carbon brushes in the Norden gyros tended to produce dust which fouled the bearings.

The Sperry ran off of 110V AC current compared to the 26V DC current used by the Norden. Whereas the Norden had all of its controls mounted on the right, the Sperry had the knobs for range located on the left and for azimuth located on the right, so that the bombardier could use both hands to adjust them simultaneously. The Norden used a manual geared system to correct for crosswind and drift, but the Sperry did this electromechanically.

The Navy would not allow the Norden to be exported, but did allow the Sperry to go to other countries such as England. The B-24 Liberator was being sent overseas (as the LB-30), and the Sperry was allowed to go with it. This led to a natural pairing of the S-1 and B-24, so almost all of the Sperry S-1's were in B-24 's. Approximately 5,000 S-1's were made, but the Norden dominated the bombsight market, and production of the S-1 ceased in 1943. Here is a video of what I believe to be is the only working Sperry S-1 in existence. The video seems long, but the second half is a tutorial on the bombing problem and solution:

ESTOPPEY D-8

The Estoppey bombsight, designed by Georges Estoppey, used a clock timer mechanism to compute the drop angle. This was a much simpler and cheaper device than the Norden or Sperry sights. There was a severe shortage of Norden bombsights just before WWII and in the early years, so Estoppeys were called into heavy production beginning in 1938. The bombardiers would wind the timer up with a crank, set the time of fall information into the front dial, then rotate the crank in the opposite direction to activate the timer. He would then look from the top wire down to the front wire, and rotate the crank so as to keep the front wire on the target. When the timer ran out, the crank was locked out, fixing the wire position. He would then shift to looking from the top wire down to the rear wire. When the target came into view, he would release the bomb. There were approximately 9,000 Estoppey bombsights produced. Here is a video of what I believe to be is the only operational Estoppey D-8 Bombsight:

SPERRY T-1

The Sperry T-1 was the American version of the British Mark XIV bombsight. The British did not have enough manufacturing capacity for wartime needs, and approached the American Sperry corporation for assistance; approximately 23,000 were made. It was composed of a computer and a sighting head, connected by rotary drive shafts. It used 60 PSI air pressure and 27V DC to drive a series of bellows and gears/levers to compute the dropping and drift angles. Prior to the mission, the bombardier would dial in the bomb terminal velocity and target height above sea level. The computer would use pitot-static input to determine airspeed and altitude. When the bombardier entered the wind speed and direction, the computer would solve for the angles and adjust the sighting head. A few of these ended up in American bombers. Here is a video of what I believe to be is the only operational Sperry T-1 Bombsight:

WIMPERIS BOMBSIGHT

WWI bombsights could not correct for drift due to crosswind. Harry Wimperis began designing a line of bombsights in 1916 to solve this problem. Because they could solve the wind vector issue, these belonged to the class known as 'vector' bombsights. The Wimperis bombsight, also known as the Course Setting Bombsight, had several models. The Mark IX was used early in WWII, and is a forerunner of the Mark XIV/T-1 shown above. Here is a video demonstration of a Wimperis Mark IXc:

LOTFERNROHR 7-D

Although the Norden bombsight was our second most highly guarded secret during WWII after the atomic bomb, Carl Norden had a Nazi spy in his New York factory, Herman Lang, that gave the design of the Norden bombsight to the Nazis prior to the War. The Nazis incorporated this information into their own gyroscopically stabilized bombsight, the Lotfernrohr 7, or “Lotfe 7”. Ultimately, the Germans did not have heavy, high altitude bombers or the need for precision bombing. Here is a video demonstration of the Lotfernrohr 7-D:

Bombardiers' Information File (BIF)

Direct link to this page:
http://aafcollection.info/items/list.php?item=000022

Authors:

• none listed

Contributors:

• Mike Voisin

Norden Bombsight Manual Pdf Download

Published: March 1945

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Item: 000022

Viewed: 13155 times

Comments: 5 (see below)

Categories:

• Armament
• Bombardment
• Training

Locations:

• Carlsbad Army Air Field; Carlsbad, New Mexico, USA

Contributors:

• Mike Voisin

Repositories:

• Private Collection

Related Items:

• 000021: Navigators' Information File (NIF)
• 000023: Radar Observers' Bombardment Information File (ROBIF)
• 000148: Pilots' Information File (PIF)

Collections:

• John E. Voisin

Added: January 30, 2007

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Comments (Add a Comment)

[1] Mike Voisin (12-Jul-2008 05:46 PM)

This book belonged to my father, John E. Voisin. He trained as a bombardier at Carlsbad, New Mexico.

[2] Reed Hammans (08-Nov-2008 01:26 PM)

This is an outstanding site--and this set of documents is particularly interesting. I just sent a link to this to a former bombardier of the 95th BG. Thanks for keeping this site updated so regularly.
Reed

[3] Tom Nicoud (12-Jan-2010 06:30 PM)

Norden Bombsight Manual Pdf Free

Dad was a bombardier with the 95th Bomb Group (H). I am part of the AZ Wing of the CAF and am doing some research on the Norden that is part of our B-17G 'Sentimental Journey'. We are trying to maintain and restore the onboard systems as accurately as is feasible.
Thanks for the great resource!

[4] Heather (29-Jul-2011 05:16 PM)

Thank you so much for posting. A very valuable reference.

[5] Deborah Bullman (18-Oct-2019 02:49 AM)

I am selling one of these. My listing will be going on ebay at the weekend. I was unsure of the rarity/value of this item. Your thoughts would be much appreciated.
Regards Deborah Bullman

End of Comments

Curator: Mike Voisin

Norden Bombsight Manual Pdf