IFR Navigation in WW2?

Colgor88

Colgor88

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Colgor88
So I was watching the Battle of Britain and got to thinking, how would navigation would have worked under IFR conditions in ww2? Of course in VFR it would just be dead reckoning and pilotage, but for IFR, we rely so heavily on electronic navigation that it’s weird to think of trying to navigate with no landmarks and no electronic guidance. I’m not just talking GPS, I’m talking flying with no VOR, NDBs, or even ADF to capture radio antennas. How would they have done it prior to an ADF, Especially for a fighter pilot who has to do it without a navigator?
 
I imagine they limited how much time they spent in the clouds.. For overall nav though you've always got a compass, stopwatch, and a map. Before GPS, sailors out of sight of land were basically IMC, and they've used compasses and stopwatch to navigate for centuries

I want to say though that radio direction finder equipment goes back pretty long, so even before adf they likely had some sort of rudimentary way to hone in on a beacon
 
i've always heard that the japanese homed in on the AM radio station broadcasts from honolulu en route to pearl harbor. i can't imagine that once hostilities commenced that all AM radio was silenced.

i talked to a WWII B-17 navigator at the Wright-Pat museum many years ago and asked basically the same thing. the 8th air force did daylight bombing over europe and if the primary target was "socked in" missions were either changed to an alternate or scrubbed altogether. the brits took over at night and he told me their navigators would actually shoot a sextant to confirm or find their location when needed. he didn't mention homing in on radio stations.

he was a really interesting guy. he was sitting on a bench admiring a P-51 which was in the same exhibit as the 17. i thought he might be a 51 pilot but he was recalling the escorts they provided. he said he flew 30-something missions over occupied europe in the same plane with the same crew. he said the last one didn't count as it occurred after the german surrender. he said the plane was crashed by a relief crew after they were sent home. i saw him once or twice being interviewed on the history channel when that channel was actually living up to their name.
 
The A-N low frequency navigation system....

https://en.wikipedia.org/wiki/Low-frequency_radio_range
radio-range.jpg

Basically, you get an "N" in Morse Code (Dahdit) if you're to one side of the beam, and an "A" (ditdah) if you're on the other. If you're flying directly toward or way from the station ON one of the beams, you get a continuous tone.

IIRC, Gann writes about using them in several of his books.

The British had a system called Gee....

https://en.wikipedia.org/wiki/Gee_(navigation)

Ron Wanttaja
 
Lindbergh got across the ocean with basically a compass and a stopwatch. Not IFR, but certainly a very long stretch with no navigational reference points.

Which is not to say that this is easy, by any means. We have it easy now by comparison, but I'll take it any day.
 
I was hoping to show a photo of the VAR (Visual Aural Range) shack next to the ramp at the Rawlins, WY airport, but it is gone.

The orange and white little building had a big exhaust vent for the generator and wires on a pole...
 
What I find interesting is the fact that the majority of WWII pilots, at least early on, weren’t “qualified” to fly in the clouds. One guy I used to work with said he was still taught to spin down through the clouds...in a PB4Y-2 (Navy version of the B-24).
 
I just read a book about this. The Gee system (mentioned above by wanttaja) was what the book mentioned. It apparently was an approach path you would listen to, and if you were too far to one side, you got "dot" sounds, and too far to the other, you got "dash" sounds, but if you were in the middle, you got a tone. So instead of a meter like a vor, you would listen, and use it like a non-precision approach.
 
You can see a direction finding loop on this WW II aircraft, although this is a modern photo. I have no idea what transmissions it was used against.

https://en.wikipedia.org/wiki/Avro_Anson

CF15_Avro_Anson_ZK-RRA_040415_01.jpg


The Germans used a radio blind bombing system to bomb London by 1940 and the RAF had Gee (similar to Loran/Decca) later.
Most Secret War by R.V. Jones is a well written book that details The Battle of The Beams and other material from a British perspective.

https://en.wikipedia.org/wiki/Reginald_Victor_Jones#Beam_guidance

  • Most Secret War: British Scientific Intelligence 1939–1945. Hamish Hamilton, London, 1978. ISBN 0-241-89746-7 (Published in the USA as The Wizard War with the same subtitle.)
 
Spring Ford said:
...The Germans used a radio blind bombing system to bomb London by 1940 and the RAF had Gee (similar to Loran/Decca) later.
Most Secret War by R.V. Jones is a well written book that details The Battle of The Beams and other material from a British perspective.

https://en.wikipedia.org/wiki/Reginald_Victor_Jones#Beam_guidance

  • Most Secret War: British Scientific Intelligence 1939–1945. Hamish Hamilton, London, 1978. ISBN 0-241-89746-7 (Published in the USA as The Wizard War with the same subtitle.)
Click to expand...

Didn't the Brits come up with a way to "bend" the beam to deflect the bombings when the targets were smaller and further north?
(difficult to hide London, even with the blackouts).
 
Not a war story, but North Star over my Shoulder by Bob Buck is a great book that touches on a lot of the navigation techniques used in the early days. He talks about some pretty squeaky instrument approaches in airliners, mostly using the four-course radio range and occasionally a fan marker, as well as climbing up into the bubble with a sextant. It's interesting stuff for anyone asking the kinds of questions the OP asked.

If you look into the history of ground-based aids to navigation, there were more or less 4 periods from what I can tell. The visual air mail route beacons, the four-course range, the VOR, and the GPS. The real transition to VOR seems to have been after WW2 although the technology was available during the war. And apparently the four-course range stations were often converted to NDBs along the way. The article about them on Wikipedia is instructive and includes both a chart excerpt and an approach plate that help get your head around how they were actually used. https://en.wikipedia.org/wiki/Low-frequency_radio_range

My own thoughts about instrument flying during WW2, not confirmed by anything more authentic than daydreaming, is that there wasn't much IFR flying to be done. The fighters were either interceptors sent up to shoot down bombers or escorts sent to shoot down interceptors that are trying to shoot down bombers, and both of those missions are VFR in nature both because the bomber missions were VFR and because it's really hard to dogfight in a cloud.

The bombers were mostly VFR missions, at least when it came to dropping bombs on visually-identified targets (which could have been as small as a factory or as big as an entire city). The bomb runs were a matter of navigating to a visually identifiable initial point, then flying the final course to the target, and dropping your bombs on target. So you didn't need any kind of instrument navigation at the target, but you needed a good navigator who could use a compass, stopwatch, chart, and/or sextant to find the IP and to find your way home after the mission.

As far as instrument approaches, any kind of radio beacon on the ground would just lead the enemy to your base, and if you turned it on only when it was in use that would just make things worse by telling the enemy when it's a good time to bomb your base. So my suspicion is that the bombers and escorts only flew missions when it was VFR at their base as well as at the target, and interceptors only had to fly when it was VFR at their base, otherwise there wouldn't be bombers coming in for them to intercept.
 
GRG55 said:
Didn't the Brits come up with a way to "bend" the beam to deflect the bombings
Click to expand...

The beams were not bent as such, it's just a radio transmission and no one knew how to make a portable black hole back then. Various strategies were used and despite having read RV Jone's book twice (at least) I can't recall enough to report here.

The V2's were diverted by feeding bad data to the Nazi's through a spy network that had been entirely compromised and the agents Doubled. Reports were sent that the missiles were falling short I think with the results that many overshot the most densely populated areas. (Or vice versa?)

https://en.wikipedia.org/wiki/Reginald_Victor_Jones#Beam_guidance

"With this knowledge, the British were able to build jammers whose effect was to "bend" the Knickebeinbeams so that German bombers spent months scattering their bomb loads over the British countryside. Thus began the "Battle of the Beams" which lasted throughout much of World War II, with the Germans developing new radio navigation systems and the British developing countermeasures to them. Jones frequently had to battle against entrenched interests in the armed forces, but, in addition to enjoying Churchill's confidence, had strong support from, among others, Churchill's scientific advisor F. A. Lindemann and the Chief of the Air Staff Sir Charles Portal"
 
There's several good books about flying the Burma hump which describe letting down in IFR conditions. Those guys were masters of the 4-course radio range approach.
 
This is a 5 hour video of what I think is an entire TV series.
Gets into the beams by 11m 36s with RV Jones. I have just started on it:)

 
Song of The Sky was written in 1954 by Guy Murchie, a journalist who had served as a navigator in the USAAF during WW2. He writes not only of navigation but also aerodynamics, weather, history of flight and more, all with a poet's touch. It's a wonderful book.

In Chapter 14 ("Magnetism of The Sphere") he recounts the wartime flight of a C-54 from the Azores to Prestwick, with eighteen American generals aboard. They encountered IMC, then unforecast winds and weather, compounded by an electromagnetic storm that made their radios all but useless. They were able to land safely, with nothing more than fumes in the tanks, because the navigator happened to remember the frequency of a secret British navigation and communication system. It's a riveting story.

The book is available through Kindle and iBooks; or if you're really cheap, the full unformatted text is here: https://archive.org/stream/songofsky00murc/songofsky00murc_djvu.txt
 
I was lucky to do my first dual Cross country flight to KFAT, where I spent some time with both the FSS guy and the National Weather Service Yoda. I learned a year's worth of meteorology stuff in two hours!

The FSS guy showed me how the VHF DF (direction finding) system worked and We went outside and looked at the antenna array. The DF station began life as a LFR (Low Frequency Range) and was re-purposed when the LFR system was decommissioned in the early 1960's.

I think the DF station is still standing at KFAT, but I wonder what or if if is used for anything anymore... They were all decommissioned in the lower 48 in 2007...

I'm probably one of the few humans to have ever used it in flight. I called them when I did the dual cross country flights with my own students. They usually found us when we were 50 or so miles away to the East of Fresno/Madera.

Here's pictures:

LFR-loop.jpg
LFR station with early loop antennas.

KFAT_DF.png
KFAT DF station.
 
iamtheari said:
Not a war story, but North Star over my Shoulder by Bob Buck is a great book that touches on a lot of the navigation techniques used in the early days. He talks about some pretty squeaky instrument approaches in airliners, mostly using the four-course radio range and occasionally a fan marker, as well as climbing up into the bubble with a sextant. It's interesting stuff for anyone asking the kinds of questions the OP asked.
Click to expand...
I second the motion on North Star Over my Shoulder; it's a great book. I especially liked the part where he describes flying from Alaska to Midway during WW 2, and hoping that the base CO didn't see his sortie posted on the board. He and his crew were doing weather research flights for the Army, and had blanket authorization to go pretty much wherever they wanted, but he was concerned that the CO might veto their destination if he found out before they left.
 
“Fate is the Hunter” by Earnest K. Gann talks extensively about pre-war ifr experiences, based on his time as an DC3 pilot for American.
 
Pilawt said:
Song of The Sky was written in 1954 by Guy Murchie, a journalist who had served as a navigator in the USAAF during WW2. He writes not only of navigation but also aerodynamics, weather, history of flight and more, all with a poet's touch. It's a wonderful book.

In Chapter 14 ("Magnetism of The Sphere") he recounts the wartime flight of a C-54 from the Azores to Prestwick, with eighteen American generals aboard. They encountered IMC, then unforecast winds and weather, compounded by an electromagnetic storm that made their radios all but useless. They were able to land safely, with nothing more than fumes in the tanks, because the navigator happened to remember the frequency of a secret British navigation and communication system. It's a riveting story.

The book is available through Kindle and iBooks; or if you're really cheap, the full unformatted text is here: https://archive.org/stream/songofsky00murc/songofsky00murc_djvu.txt
Click to expand...
That was as good a war story as I've read in a long time. Another link here: http://www.oceannavigator.com/January-February-2003/Secret-elecronic-nav-aid-saved-WW-II-flight/
 
iamtheari said:
My own thoughts about instrument flying during WW2, not confirmed by anything more authentic than daydreaming, is that there wasn't much IFR flying to be done.
Click to expand...
My recollection of what I have read (or perhaps heard from bomber crew), was that bomb runs were often launched into hard IMC and they would circle up through the clouds to get on top and join in formation - mid air was a big concern with hundreds of aircraft departing from dozens of airfields...
There was also a system where they would light up a ditch full of avgas on each side of the runway to burn away fog for landings. Don't recall if that was just an experiment or not.

Losses were expected.
 
Capt. Geoffrey Thorpe said:
There was also a system where they would light up a ditch full of avgas on each side of the runway to burn away fog for landings. Don't recall if that was just an experiment or not.
Click to expand...

I believe it was used operationally.

https://en.wikipedia.org/wiki/Fog_Investigation_and_Dispersal_Operation
"At an attempt to quantify the saving of aircrew life, Bruce Main-Smith suggests possibly 11,000 airmen"
300px-IWM-CH-15271-FIDO-Lancaster-Gravely.jpg


FIDO used huge quantities of fuel, as much as 100,000 gallons (125,000 US gallons, 450,000 litres) per hour. ... Although extravagant in the use of fuel consumed, the device more than made up for the costs involved in the reduction in aircraft losses.
...
The last FIDO-equipped airfield at which a system was maintained was RAF Manston, the system being available for emergency use as late as 1952. Due to the high costs involved, use had to be reported to the Air Minister.
...
FIDO was also installed at North American airfields including Arcata, California, Eareckson Air Station, Naval Air Station Whidbey Island, at the World War TwoAmchitka Army Airfield on Amchitka Island in the Aleutians.[3] It has been used to bring commercial planes into fog-covered airports in the United States.
 
Back in 1980 I got to ride on a Lockheed Learstar from Honolulu, Christmas Island, Canton Island and then Pago Pago, American Samoa. There was 4 of us, Captain, Co-Pilot, mechanic, and me. From what I remember we had Loran for about 1/3 of the way to Christmas. The rest of the trip was dead reckoning and ADF's. The ADF on Canton was only turned on when needed. It got exciting on the leg to Canton when we had to shut down an engine and they turned on the ADF at Canton late. If I remember right we worked on the engine for two days and got it running well enough to make Pago Pago. In Christmas we had been fueled out of barrels with a had pump, one of the barrels must have had bad fuel. I believe it was 6 hours to Christmas and it took them 6 hours with the hand pump to refuel us. We spent one night in Christmas.

The original plan was to fly from Canton back to Honolulu but that changed with the engine problem. They decided to fly to Pago Pago, which was closer, to get parts. We picked up people at Canton that had been trying to get off the island for several months.

When we got to American Samoa I jumped ship.

IMG00123.jpg
 
Thanks to Ron for the diagram of the old 4 course LF nav system. There were approach procedures published too. Some of the terms changed over time. Example: "High station" and "Low station" became "IAF" and "FAF". The system remained in place until the mid 1960s when they were converted to NDBs. In fact, Airway Amber 7 ran from FL up the east coast, through Maine and into Canada.
I got to use it in late 1960 to take the practical for my PPL. I had trained under the CAA requirements and joined the Marines before I got my pvt. The CAA went away in 1958 and the FAA was created with different requirements for the PPL. 1.Use a radio. (Did that in the Marines) 2. Fly by instruments. (Had some Link time with the CAP long ago) 3. Navigate by radio nav aids. (Thats new!)
My CFI had a J-3 with an ancient com radio, another ancient LF receiver, a battery on the floor, and a wind generator. A T&B and VSI were added. Off we went. Amber 7 ran right through the traffic pattern.
Step one: orientation. Find out what quadrant you're in. Step Two: maintain on course with the steady tone. The dit dah of morse A merged with the dah dit of the N to make a steady tone. It got louder closer to the station. Got good at it. Cubs are easy. Got my PVT.
Fast foreward to 1966. I'm in the National Guard in the back seat of a BirdDog and a WW2 vet is up front (there were 4 in the unit) showing me a manual loop approach to AUG NDB. It used to be AUG range (four course)before it was converted. Step one; resolve 180 deg ambiguity. Impressive in that the LF receiver and loop control was up in the left wing root in the L-19. Manual loop dates back prior to WW2. The LF loop is visible aft of the wing. Another nav aid is the FM homing antenas barely visible on the LE of both Hor Stabs.
Recently saw a picture of the 1944 era C47 Thats All Brother, that has an array under the cockpit window. It sure looks like the L-19 "cat wiskers" on the tail. The L-19's could home in on a backpack tac radio.
L-19-Bird%20dog-best-w-brdr.jpg
 
The FM homing equipment is used to home in on the FM tactical radios by one of the two antennas getting a slightly stronger signal than the other. The signal went into a keying unit about the size of a car battery. Then fed to the LF receiver. In the older Korean war era gear, it converted it to either a morse D dah dit dit or a morse U dit dit dah. When signal was dead ahead, the two codes merged into a steady tone same as the four course nav system. By the VN era,no more d's and u's. A small CDI provided L R guidance. I guess that the system on Thats All Brother worked something like the Korean era gear.
 
IK04 said:
I was lucky to do my first dual Cross country flight to KFAT, where I spent some time with both the FSS guy and the National Weather Service Yoda. I learned a year's worth of meteorology stuff in two hours!

The FSS guy showed me how the VHF DF (direction finding) system worked and We went outside and looked at the antenna array. The DF station began life as a LFR (Low Frequency Range) and was re-purposed when the LFR system was decommissioned in the early 1960's.

I think the DF station is still standing at KFAT, but I wonder what or if if is used for anything anymore... They were all decommissioned in the lower 48 in 2007...

I'm probably one of the few humans to have ever used it in flight. I called them when I did the dual cross country flights with my own students. They usually found us when we were 50 or so miles away to the East of Fresno/Madera.

Here's pictures:

View attachment 76557
LFR station with early loop antennas.

View attachment 76558
KFAT DF station.
Click to expand...

I got a DF Steer from Daggett Radio once. Just practice, wasn't lost. They got my distance by having me 'transmit' then giving me a heading to fly. It was 90 degrees to the Bearing I was on. They waited awhile and then had me 'transmit' again. They did the triangulation and gave the distance. I was able to verify it as being pretty darn close by checking it against landmarks on the ground.
 
Jimmy Doolittle made the first "blind flight" nearly ninety years ago (September 24, 1929), taking off, flying a set course, and landing while under a fabric hood and unable to see outside the airplane. He relied entirely on a directional gyro, artificial horizon, sensitive altimeter, and radio navigation.

Doolittle and the First "Blind Flight"

BTW, Doolittle received his PhD in aeronautical engineering from M.I.T. in 1926.
 
The mission to intercept and shoot down Adm. Yamamoto is the most amazing dead reconing exhibition I can imagine. 600 miles to get there (not direct to avoid detection) and 400 mile return to base. They arrived at the rendezvous point 1 minite early. The P38s were equipped with ships compasses.
 
Perhaps others have pointed this out, but while the four-course range, ADF/NDB etc existed before and during WW2, obviously these were limited or non-existent on tactical long-range missions, such as to a distant target.

In most of the books I've read, the short answer seems to be... pilotage. There was use of celestial navigation when available, and perhaps radio nav when in range, but generally my impression is that they talked with the weather staff ("aerologists" in one memoir), decided on a compass bearing and time, then flew it and monitored progress.

I recently enjoyed "Flights of Passage" by Samuel Hynes, and several times he discusses doing just this from one south pacific island to another in his TBM - and even around the base in Pensacola. It seemed to me they were very good at dead reckoning, pilotage and recognizing landmarks.

There is a B-29 crewmember in my CAF wing who served in the South Pacific in 1944-45 ... I'll ask him.
 
Cap'n Jack said:
Although it was more VFR on top, a lot of navigation and bomb targeting was via RADAR.
Click to expand...

I disagree with your characterization. The USAAF's H2X, or Mickey (officially called AN/APS-15) radar wasn't fitted to a B-17 until October 1943. Its first use in combat was in April 1944. The previous version, H2S, saw very limited use, as its longer wavelength produced imagery that made bombing through overcast highly inaccurate.

It took many more months before a significant number of new B-17Gs and B-24Ds equipped with the radar arrived in England.

Most bombing operations between April 1944 and April 1945 were carried out using visual navigation and the Norden bombsight.
 
The Cibola County (NM) Historical Society has restored an original beacon, generator shed, and Flight Service Station of the Midcontinental/TAT Airway. Their Air Heritage Museum is the only surviving station on the Airway.

Take a look, they've done a fantastic job of preserving history.

http://www.cibolahistory.org/airway-heritage-museum.html

@Zeldman
 
Last edited:
3393RP said:
I disagree with your characterization. The USAAF's H2X, or Mickey (officially called AN/APS-15) radar wasn't fitted to a B-17 until October 1943. Its first use in combat was in April 1944. The previous version, H2S, saw very limited use, as its longer wavelength produced imagery that made bombing through overcast highly inaccurate.

It took many more months before a significant number of new B-17Gs and B-24Ds equipped with the radar arrived in England.

Most bombing operations between April 1944 and April 1945 were carried out using visual navigation and the Norden bombsight.
Click to expand...
The RAF was using H2S in 1943.
...Bomber Command relied increasingly on the radar to guide planes beyond the nearly 300 mile range of Oboe and other precision navigation devices. The magentron's 10-centimeter waves never provided the resolution to pinpoint targets, but they were good enough for all-weather area bombing. Radar became Butcher Harris's bread-and-butter: H2S was used on 32,000 of 53,000 sorties in 1943
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Buderi, R. The Invention That Changed the World.Simon & Schuster,1996, p.210
That's quite a bit more than "limited use"

The inaugural H2X usage was November 3, 1943, against Wilhelmshaven (reference above, p. 212)
 
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