Aircraft


© Brooke Clarke 2018

Background
Topics
    Maximum Altitude
    Compass
    GPS
    Gyroscope
    Bombing
        Patents
    Documents
    Fighter Performance
    Shooting Down
    Close Air Support
    Gunships
    Anti Submarine Warfare
    Simulators
    Electronic Warfare
Photos
Patents
Related
References
Links

Background

It turns out that a number of my web pages are about things related to aircraft so I've started this page for aircraft related things.

Topics

Maximum Altitude

This is a consideration that applies to airplanes like the U-2 (Ref 9, Ref 13, Wiki), A-12 (Wiki) and SR-71 (Wiki) as well as to the altimeters they use.
A key consideration for heavier than air craft is called wing loading (Wiki).  This determines stall speed which in turn relates to maximum altitude.  Key factors in max altitude are air density, wing area and total aircraft weight.

Compass

A magnetic compass is influenced by nearby ferrous metal as well as be nearby magnets.  Both types of influence can be compensated but even after doing that there's still the problem of the Earth's magnetic field vector being more up and down than horizontal near the magnetic poles, i.e. near the poles a magnetic compass does not work reliably.  So a number of approaches were used to determine bearing.  Note there is a severe problem with a magnetic compass in a metal vehicle like a submarine, ship or armored tank or even an automobile. 
Abrams Universal Sun Compass SC-1 - actually used in the desert in W.W.II for vehicles
AC_D500 Astro-Compass MkII - This is what amounts to a transit without a telescope for determining angles to the Sun or other heavenly body from an airplane
Aircraft Pilot's Standby Magnetic Compass - a backup to more complex systems that do fail now and then
KVHC100FG KVH C100 Flux Gate Compass module - mainly used on watercraft and on land, but the concept dates way back in aircraft
MC1 MC-1 Magnetic Compass Calibration Set similar to AN/ASM-344 - used for aircraft
MD1 Automatic Astro Compass Type MD-1 - a star tracker that works day and night to locate an airplane

This is related to Navigation - Gyroscope

GPS

In 1943 (Ref 1) radio aids to navigation were things like Radio Direction Finding working with known transmitter locations (like AM broadcast stations or NDBs (Wiki), to provide a bearing and beacons of the A/N type (Wiki).  Dead Reckoning and Celestial Navigation were required skills.  LORAN-A (Wiki) was developed during W.W.II and LORAN-C by 1958, but it was mainly used by ships then.  By 1981 (Ref 3) VOR (Wiki), TACAN (Wiki), Omega (Wiki), autopilots (Wiki) were in common use. Note LORAN-C (LORAN-C, Wiki) was not common on aircraft yet. 

Modern aircraft use GPS to determine their position.  Note that GPS by itself does not inherently have a bearing output.  But because the aircraft is moving when in the air it can develop a bearing by calculating the difference in positions.
5001A Stanford Telecom 5001A Navstar Test Transmitter - made to test their GPS receiver ICs - an early simulator to test GPS receivers
AstechZ12 Ashtech Z-12 Reference Station GPS receiver - a GPS receiver used at reference stations on the ground that can output Differential corrections that make GPS receivers more accurate, mainly used for ships and surveying.
CSI LGBX Pro DGPS Receiver - A combined GPS and differential correction receiver mainly used for surveying
DAGR - Defense Advanced GPS Receiver - a current military GPS receiver
GPSpat GPS & Satellite Navigation Patents
HNV600 Rockwell Trooper GPS HNV-600 & HNV-960
HNBV-960 GPS receiver without front panel, but has antenna & backup battery
HNV-2000 Rockwell HNV-2000 PLGR II SPGR GPS Receiver
HP Z3805A Time & Frequency GPS Receiver - mainly for fixed location use for timing applications
Jackson Labs - LTE-Lite GPSDO Evaluation Kit - mainly for fixed location use for timing applications
KS-24361 (Lucent ) HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812A GPSDO System - mainly for fixed location use for timing applicationsin cell towers
Magellan GPS Commander - mainly for ships
Magnavox MX7221 GPS Receiver - guessing military or civilian use
NTgpsSTR2760 Northern Telecon GPS Satellite Sumulator STR2760  - a more modern GPS simulator than the ST 5001
PLGR PLGR GPS Family - the military GPS receiver prior to the DAGR
PSN-8 PSN-8 GPS receiver - a very early GPS receiver
PSN-9 GPS receiver - another very early GPS receiver
PSN-10 SLGR GPS receiver -another name for the Trimble Trimpack the first widley used military GPS receiver
PSN-11 PLGR GPS receiver
PSN-13 DAGR GPS receiver
Q5200 Quantic Q-5200/SM Timing GPS Receiver
ThunderBolt Trimble GPS Timing receiver
Trimpack Trimble Trimpack Family of GPS receivers
URN502 URN-502 Vehicle Mount GPS Receiver System - a very early GPS receiver (the largest one I have)
Z3805A Time & Frequency GPS Receiver - mainly for fixed location use for timing applications

Gyroscope

The gyroscope is used in many different types of aircraft applications.  Most of them are obvious, like the turn and bank indicator or for navigation functions, but the one that was part of the reason for making this web page was the Norden Bombsight.   It turns out that it NEVER worked.  The US Navy developed the Norden, but gave up on it and adopted dive bombing.  The US Army took up the Norden, but it did not allow "precision bombing" and that tactic was abandoned and "carpet bombing" (Wiki) was the only one used.

Bombing

When most people think of a bomber (Wiki) they think of the W.W. II B-17 (photos, Wiki), B-24 (Wiki) or the more modern B-52 (Wiki).  Many movies about W.W.II show German Stukas aka: Junkers Ju 87 (Wiki) and American SBD Dauntless (Wiki) in actual dive bombing for some reason the difference between horizontal (Wiki) and dive bombing (Wiki) is misunderstood.

The Norden Bombsight (Wiki) has had a lot of publicity, but in fact it did not work.  As far as I can tell horizontal bombing only works in carpet bombing mode, with atomic weapons, or maybe using Smart Bombs (Wiki).  I think the jury is still out on the Smart Bombs.  Note bomb sights for horizontal bombing look down whereas sights for dive bombing look forward and are often called "gun sights", for example the Mk 20 Mod 4 Gun-Bomb-Rocket sight.

Dive bombing goes back as far as airplanes carrying bombs (Ref 5, Ref 6).  The bombsight looks forward and can easily be confused with a gun sight.

I'm investigating the use of the A-1 Skyraider (Ref 7) in the dive bombing role.  Note it's bombsight is above the instrument panel looking foreword, just like the 3x "rifle scope" bombsight on the Douglas SBD Dauntless (Wiki).  The late model SBDs used the Mk 8 sight.  But I don't remember ever seeing a movie showing the A-1 in the dive bombing role.
YouTube: Saga of the SkyRaider - A-1 Spad 80510 - (3:25) "The Navy had been searching for a new dive bomber, attack aircraft to meet the changing tactical and operational requirements."

YouTube: VNAF A-1E Skyraider Air Strikes, Vietnam, 11/19/1964 (full) - (0:22 - Clearly dive bombing
YouTube: Napalm Hell-The Opening Scene of Rescue Dawn (2006) in HD - For Napalm the A-1 seems to be using horizontal bombing were there is no bomb sight.
Mk 20 Mod 4 gun sight is the sight used on the A-1 Skyraider.
http://www.aircraft-gunsights.com/reflector-sights/

The thing that may have put an end to dive bombing is the advent of Radar controlled Anti-Aircraft guns (
Wiki:  ZSU-23-4) in 1962.  The 23mm rounds are too small for Proximity fuzes (China Lake Patents, Wiki) so a direct hit is needed. Prior to 1962/1963 dive bombing would work, but after that the planes could be easily shot down.  Surface to Air Missiles (Wiki: SAM) were deployed in Vietnam starting about 1965.

In Toss Bombing (aka: Low Altitude Bombing (LAB, Wiki) the plane is pulling up at the point of bomb release. also see 1955 patent 2898809.

Patents

For Aircraft sight patents (gun, bomb, torpedo, Etc.) see: Mk 20 Mod 4 Gun-Bomb Sights: Patents

Propeller dive bombers need a way to keep a bomb from hitting the propeller.  Either by having the bomb rack outside the prop circle or by a special mechanism that pushes the bomb outside the prop circle.
2386839 Bomb
                      displacing gear, George A Bronson, Douglas
                      Aircraft Co Inc, 1942-12-01

Photo from Pacific Aviation Museum -
Douglas SBD view of
                      bombs & bomb racks

2386839 Bomb displacing gear, George A Bronson, Douglas Aircraft Co Inc, 1942-12-01 - probably for the SBD (Slow But Deadly)
"This invention relates to a bomb displacing gear for use on an airplane in conjunction with a bomb rack or other bomb carrier which is constructed to release the bomb at the will of the air craft operator, and particularly to a bomb displacing gear for use on dive bombing airplanes. The bomb rack is usually placed in a bomb bay formed in the under surface of the fuselage, both to keep the plane aerodynamically clean, and to bring the weight of the bombs nearer the level of the center of gravity of the plane.

In dive bombing, the diving angle is preferably between 70 and 90 degrees to reduce to a mini mum the gravity deviation of the bomb trajectories from the direction of the dive and the consequent need for allowing for this deviation in sighting the airplane for the dive. The bombs released at the end of the dive, being aerodynamically cleaner than the airplane, tend to fall more rapidly than the plane. In high angle dives the bomb trajectory after release is nearly parallel to the fight path of the airplane.

If the trajectory begins at the undersurface of the airplane, there is danger of the bombs falling into the propeller blades and breaking them or being exploded. Accordingly, devices have been employed to move the bomb upon its release from the bomb rack to a position sufficiently displaced outwardly from the fuselage that the bomb trajectory will clear the path of the propeller even in 90 dives."

Note trapeze on bomb at centerline needed to clear prop. 
The wing mounted bombs do not need the trapeze since they will clear prop.
The bombsight was a 3X telescope on plane centerline at pilots eye level.  The pilot needed to put his eye on the eyecup so that the crosshair was correctly on target (no parallax (Wiki).   The later model bombsight was a reflex type (NC-3 , Wiki) where the cross-hair stays on the target and the pilots head moves side to side. 

2461967
                      Aerodynamic Retarder, Leo J Devlin, Edward H
                      Heinemann, Douglas Aircraft Co Inc, 1949-02-15
2461967 Aerodynamic Retarder, Leo J Devlin, Edward H Heinemann, Douglas Aircraft Co Inc, 1949-02-15 - "...actuated preparatory to initiating or terminating a. dive..." Dive Brakes

2466980 Missile
                      ejector for aircraft, George A Bronson, Douglas
                      Aircraft Co Inc,, 1949-04-12
2466980 Missile ejector for aircraft, George A Bronson, Douglas Aircraft Co Inc,, 1949-04-12 - bomb rack for dive bomber
a cannon shoots the bomb away from the plane so it will clear propeller circle

Skyraider & Atomic Bomb (Wiki:Mk 4 1949 - 1953?) ?
or maybe just an improvement for iron bombs

2609729 Bombing instrument for aircraft, Wilkenson Erik Alvar, Faxen Per Torsten, 1952-09-09  - improved dive bombing improved dive bombing



AD Skyraider (later called A-1)
D146221
                      Airplane, Edward H. Heinmann & Leo J. Devlin,
                      Jan. 14, 1947

D146221
                      Airplane, Edward H. Heinmann & Leo J. Devlin,
                      Jan. 14, 1947

D146221
                      Airplane, Edward H. Heinmann & Leo J. Devlin,
                      Jan. 14, 1947
D146221 Airplane, Edward H. Heinmann & Leo J. Devlin, Jan. 14, 1947





Documents

NAVPERS 10826 See Ref 17 below
NAVORD OD 9239

Fighter Performance

Boyd (Ref 10) developed the Energy-Maneuverability theory (Wiki: E-M Theory) where a chart can be used to compare two aircraft to see how the compare in a dog fight at various altitudes and speeds.  It will show which plane has the advantage given pilots that can get everything out of each plane.

Boyd says that the Air Force seems to think heavy bombers that can deliver atomic weapons are their main mission and fighters have been neglected.  I'd say that close air support and dive bombers have also been put way down on the priority list and need to be reconsidered.

Shooting Down

It turns out the Flak (Wiki) in W.W.II while demoralizing to aircrew members was not effective in shooting down aircraft.  This is because it was virtually impossible to set the time fuze and aim the gun so that the round exploded anywhere near the target aircraft.  The National Defense Research Committee (Wiki NDRC) had as one of it's projects the development of the proximity fuze (Ref 4, developed partially at China Lake) which was used not only to shoot down aircraft but also to attack ground troops.

The Sidewinder missile (Wiki) was developed at China Lake and makes use of thermal IR for terminal homing.  Note that the sidewinder was NOT intended for air to air combat (Wiki: Dogfight), but rather to shoot down high altitude bombers.

Surface to Air Missiles (Wiki: SAM) really began when the SA-2 (Wiki) became operational and one of its first targets was the U-2 shoot down on May 1, 1960 (Wiki).  Each Surface to Air system that uses RADAR has a threat envelope in terms of diameter and altitude that's shaped like an upside down water drop.  Some are tall and skinny, some are short and fat.  If an aircraft avoids flying through the threat envelope he can not be shot down by that weapon.  Even inside the threat envelope and aircraft can evade the threat if the pilot knows the type of system and that he is being painted early enough, i.e the function of the Radar Warning Receiver (see EW below).

At a meeting of the Air Scouts in the late 1950s at Moffett Field while up close to an F-8 Crusader Jet (Wiki) we learned that the guns had been upgraded from .50 caliber to 20mm.  The reason was that the planes almost shot themselves down.  This happened when firing the guns at a barge being towed a safe distance behind a ship.  The problem was that after firing the guns the F-8 could speed up and get in front of the bullets which then hit the F-8 from behind when it slowed.  Note for landing and takeoff the wing leading edge is raised up rather than use flaps. (photo on Wiki page showing wing in up position)

Close Air Support

CAS (Wiki: action against hostile targets  that are in close proximity to friendly forces and which requires detailed integration of each air mission with fire and movement of these forces...).  In the Vietnam era the Douglas A-1 Skyraider (Ref 7, Wiki) had an excellent reputation because of its long loiter time.  Carrier based jets had a very short loiter time because of high fuel consumption.

The A-10 Warthog (Wiki) is the replacement for the A-1 Skyraider  The A-10 is turbofan (Wiki) powered and its main gun is the GAU-8 30mm cannon (Wiki) which has been shown to be very effective against tanks.  But I think improperly positioned firing forward instead of off the left wing like in Gunships (Ref 2).  The gun sight used on the AC-47 Spooky (Wiki) gunship is the Mk 20 Mod 4, the same as the sight on the A-1 Skyraider.

In order to call in air strikes a team consisting of an Army and an Air Force would man a radio such as the GRC-206 (GRC-206, MT-6250) that would be mounted on a Jeep or later HMMWV. Note the generator for the Jeep mounted system (MEP-25) burned gasoline like the Jeep, but the generator was changed to a Diesel burning model with the introduction of the HMMWV so they would use the same fuel.

Gunships

One of the earliest proponents of the pylon turn (Wiki) gunship (Wiki) was Gilmour Craig MacDonald (Ref 2) who proposed it as a way of attacking surfaced submarines in W.W.II.  Note that a standard aircraft turn (Wiki) is measured in minutes with 2 minutes being a standard rate turn.  Planes flying faster than 250 kn might make a 4 minute turn and slower planes may make a 1 minute turn.  Note this is related to wing loading (see above) Even W.W.II subs can dive in less than 2 minutes, so after the first strafing run when the plane completes its turn the sub will be gone.  This is why in W.W. II sub movies they are practicing to shorten the time to dive.

This same idea applies to aircraft engaging targets on the ground.  The AC-47 Spooky (Wiki) was the first real application of the idea.  It's based on the C-47 (Wiki) aka DC-3 (Wiki) cargo plane.   It used the Mk 20 Mod 4 Gun-Bomb-Rocket Sight which can be adjusted for these different functions, all of which look forward since dive bombing uses a sight very similar to a gun sight.

I think the A-10 would have been better if the gun was installed in the wing instead of firing forward.  From the Wiki Pylon Turn web page "...the gunfire was accurate enough to be used even in close proximity to friendly troops,..."

Since gunships carry multiple Gatling (Wiki: Mini, Gatling) guns they are typically are made from cargo planes that can carry the weight of all the ammunition.

The term gunship has also been applied to helicopters, trucks and boats. 

Note an airplane at 3,000 feet (1,000 yards) is out of range for small arms. 

Anti Submarine Warfare (Wiki)

While the destroyer (Wiki) was designed to hunt and kill submarines, (they were called originally "submarine destroyers" and that name got shortened to destroyer) it's not that good at it.  A much better option is to use aircraft for this purpose.  When I lived in Mountain View, California the local Moffet Field Naval Air Station (Wiki) was used for training pilots and as a base for the P-3 Orion Sub hunters (Wiki).  They make use of radar, sonobuoys and MAD (Wiki) to detect subs and also have weapons that can destroy them. (Ref-12)

Trivia: Hanger One (Wiki) was the 1930s home for the USS Macon (ZRS-2) (Wiki) rigid airship and has very large hangers built for blimps.  This is where the Air Scouts met in the late 1950s.

The most powerful anti submarine strategy in W.W.II was the use of aircraft.  Even when planes were not armed submarines were afraid of them.  Destroyers were not very effective in protecting convoys in the Atlantic but when merchant ships were converted to be short aircraft carriers the level of protection went way up.

Simulators

In the late 1950s the Air Scouts met a Moffett Field and one of the sessions involved time in a flight simulator.  It was maybe 6 to 8 feet wide and maybe 20 to 30 feet long.  Fixed to the ground and no pilot's outside visual simulation, that's to say pure instrument flying.  In addition to the cockpit with opaque canopy there was an instructor position that had a duplicate set of instruments and in addition a plotting board.  The instructor had inputs and could "make things happen".  The interesting thing was the cockpit was illuminated by UV light and the instrument markings glowed.  This allowed the pilot to maintain his night vision when flying at night.  If white instrument lights were used that would not be the case.

Link (Wiki: Flight Simulator, Edwin Link), Link Trainer) had a factory in Sunnyvale that's now the location of Fry's Electronics.  Some key parts of a flight simulator are the instruments, outside visuals and physical movement (Ref 8).

Electronic Warfare

To counter aircraft ground troops can use RADAR directed guns and missiles.  The aircraft can defeat this by using Radar Warning Receivers which let the pilot know the rough bearing to the threat, what kind of threat it is and if a missile has been launched.  In some cases radar suppression flights (Ref 11) might launch an Air to Ground Missile (AGM) which can home on the RADAR signal such as the Shrike (Wiki) or HARM (Wiki).

Another aspect of EW is jamming (Wiki).  During W.W. II communication jammers (Hexjam)were developed, but typically were not used since it was more valuable to listen in to learn what the enemy was up to.  This included breaking their secret codes and ciphers.  I have a number of pieces of military voice security (CryptoM) and key loading equipment (CryptoM).

Photos

Most of the aircraft photos I've taken are of things flying over my house or at the local airport.  Taken by steeping out the front door and looking up.  See:
Ukiah Airport and scrolling down.

Related

China Lake Patents - Sidewinder, Proximity Fuze & Others
Electro-Optical Gadgets - Grimes AN-3038-2A aka C-5A UV Cockpit Light - MODEL 9379640 Cockpit light -
FN FAL - Types of Sights -
Gibson Girl AN/CRT-3B life boat survival beacon transmitter
GRC-206 Program Pacer Speak & MT-6250 - Forward Air Controller
Gyroscopes - Norden Bomb Sight
MD1 Star Tracker Navigation System
Mk 20 Mod 4 Gun-Bomb Sight
Navigation
Navy Mk. 18 Gun Sight
Optics
Outdoor Intrusion Alarms - Vietnam era
Radar Warning Receivers - AM-6536 - AN/ALR-54 LAMPS
Ruger SP101 Laser Sight
Sonobuoys - Underwater Locator Beacons & Roswell Connection - CRT-1B
Submarines
Torpedoes - "Range" problems with torpedoes, battleship guns, depth charges, horizontal bombing
Ultra Violet light -
Wallace & Tiernan FA 181 Altimeter, Barometers & Altimeters, Aneroid (aircraft instruments)

References

Aircraft
                      Books


Ref 01 Air Navigation, Weems, 1943 -
Ref 02 The United States Air Force in Southeast Asia: Development and Employment of Fixed-Wing Gunships 1962-1972, Jack S. Ballard, 1972 -
Ref 03 Aviation Electronics, Keith W. Bose, 1977 -
Ref 04 The Deadly Fuze: Secret Weapon of World War II, Ralph B. Baldwin, 1980 -
Ref 05 The History of Dive Bombing, Peter C. Smith, 1981 -
Ref 06 Dive Bomber!, Peter C. Smith, 1982 -
Ref 07 Skyraider: The Douglas A-1 "Flyhing Dump Truck", Rosario Rausa, 1982 -
Ref 08 Flying without Wings: A flight simulation manual, Paul Garrison, 1985 -
Ref 09 Spyplane: The U-2 History Declassified, Norman Polmar, 2001 - (prior book owner Ed Lovick who wrote RADAR Man, father of Stealth) -
Ref 10 Boyd: The fighter pilot who changed the art of war, Robert Coram, 2002 -
Ref 11 First in, Last Out: Stories by the Wild Weasels, edited by Colonel Edward T. Rock, USAF, 2005 -
Ref 12 The Ears of the Air ASW: A History of U.S. Navy Sonobuoys, Holler, Horbach & McEachern, 2008 -
Ref 13 Radar Man: A Personal History of Stealth, Ed Lovick, 2010 - his time at Lockheed skunk works
Ref 14 Aircraft Versus Submarine 2004 -
Ref 15 Ed Heinemann 1980 -
Ref 16 By Sea, Air, and Land 1992
Ref 17 Naval Airborne Ordnance NAVPERS 10826-A 1958 (1961)
Ref 18 United States Naval Aviation, 1910-1995, 1997
Ref 19 Navy Attack: Spads, Scooters & Whales 1990 - excellent photos
Ref 20 America's Pursuit of Precision Bombing, 1910-1945 - 1995 - about how horizontal bombing never worked

Links

AIRCRAFT GUNSIGHTS
Glenn’s Computer Museum - with some mechanical computation element - Old Bombsights, Gun Sights & Navigation Computers -
National Air and Space Museum - A-1C Gun-Bomb-Rocket (GBR) Sight -
A-1 Skyraider Combat Journal - Byron E. Hukee
The Official Website of the A-1 Skyraider Association
The Able Dogs -
The Pacific War Online Encyclopedia - Dive Bombers - "The best naval dive bombers in the Pacific War could maintain a dive angle of perhaps 70 degrees. A dive this steep could easily build up enough velocity for the aircraft to become impossible to control: As the speed of the air flow across some control surfaces approached the speed of sound, the control surfaces became useless. To avoid this difficulty, and to ensure that the aircraft could pull out after dropping its weapon from an altitude low enough for accurate bombing, dive bombers were generally equipped with some form of dive brake."
ibiblio.org - USN - General References Aircraft Armament - Mk 14 Gun Sight (requires clean dry compressed air for the gyros) -

PRC68, Alphanumeric Index of Web pages, Contact, Products for Sale
Page Created 27 Aug 2018