OK, WW2 Radio Direction

[md2000]

@Paul_in_Qatar

Accuracy is good, but what we need(ed) to do was to force the Germans to fight on a new front, air defense. V2 ballistic missiles are expensive and do not force the Bad Guys to defend. V1s are cheap but demand expensive AA guns and lots of fighter planes.

“He they come, rising to meet our thunder!”

In that case, why use detectable, predictable radio beacons. The buzz bomb would have to follow that path, meaning the defensive units could concentrate around that path.

Having clockwork air-launched V1 from totally random locations anywhere between Lands End and the Swedish border, especially at night when they were not visually detectable, would provide a more interesting challenge for defence.

[Paul_in_Qatar]

Yes, but… (Hold on, let me get back to you on that.)

Part of the reason for opening of the Air Front is to impose a burden on the industrial base. The factories are in the cities. Blasting the cities would require the Germans to waste resources defending and repairing stuff.

[doorhinge]

In 1944, Operation Aphrodite used old B-17 and B-24 stripped of their bomb racks, weapons systems, oxygen system, flying suit heaters, etc which were replaced with a cargo of 30,000lbs of Torpex and radio controlled television cameras, radar, and flight controls. A pilot and flight engineer were still required for takeoff but they parachute out at 2,000 feet after arming the Torpex and turning control over to a trailing aircraft.

The program was not very successful. Joe Kennedy Jr., older brother of JFK, died during one of these flights when the Torpex exploded before they could bail out.

Magnetic compasses are not that accurate for long range direction finding because the Earth’s magnetic field is not stable. Mag north changes. Sailing charts compensate for this effect.

The jet stream was just beginning to be understood and weather prediction was poor at best. Headwinds, crosswinds, and tailwinds would make it difficult to estimate where an aircraft would be at any particular point in time.

Long distance radio signals could be jammed, which is why a trailing aircraft was required. The V-1 program required confirmation of impact sites from Nazi spys in England. Double-agents sending false confirmations caused the V-1 flight path programmers to redirect V-1 away from their intended targets (although they still caused damage).

[Bookkeeper]

The Germans actually did launch V-1s from modified Heinkel 111 bombers, but they just used the standard internal guidance mechanisms, and were likely even less accurate than the ground-launched ones.

[Chronos]

Quoth md2000:

There are no such thing as radio “beams”. You can’t focus radio like a laser.

Not only is it possible, it’s a lot easier to do with radio than with visible light. Masers were developed well before lasers.

[Kevbo]

@Paul_in_Qatar

You are thinking of the US Kettering Aerial Torpedo. It was a drone biplane with a propellor that arrived just a little too late for WWI. Remarkable it claimed an accuracy of 1% or range. This was comparable with tube artillery of the era.

Wasn’t thinking of that, because I never heard of it. From the wikipedia article on the V1 (V-1 flying bomb - Wikipedia)

An odometer driven by a vane anemometer on the nose determined when target area had been reached, accurately enough for area bombing. Before launch, the counter was set to a value that would reach zero upon arrival at the target in the prevailing wind conditions. As the missile flew, the airflow turned the propeller, and every 30 rotations of the propeller counted down one number on the counter. This counter triggered the arming of the warhead after about 60 km (37 mi).[10] When the count reached zero, two detonating bolts were fired. Two spoilers on the elevator were released, the linkage between the elevator and servo was jammed and a guillotine device cut off the control hoses to the rudder servo, setting the rudder in neutral. These actions put the V-1 into a steep dive.[11][12] While this was originally intended to be a power dive, in practice the dive caused the fuel flow to cease, which stopped the engine. The sudden silence after the buzzing alerted listeners of the impending impact. The fuel problem was quickly fixed, and when the last V-1s fell, the majority hit under power.

The same article indicates that the steering system was gyro driven, but there was a magnetic compass used to correct the drift of the gyros.

[doorhinge]

@ralph124c

When I was a kid, my Dad had a huge Grundig multi-band radio. We’d switch it to the shortwave bands and tune in these weird stations that just emitted a constant roaring tone (these were air navigation beacons).
Are they still used?

Not that I’m aware of. There are much better, more accurate, systems available today.

The Smithsonian Air and Space Museum has a copy of the Parker Brothers 1941 board game “Flying the Beam” which demonstrated how the radio range navigation system worked.

-A radio beacon sent out signals in a pattern of Morse code A’s (dot-dash) and N’s (dash-dot).
-Where the signals intersected, they combined to produce a continuous tone, which a pilot could follow toward the radio beacon.
-If the aircraft strayed from the center of the beam, the signal for either an “A” or “N” alerted the pilot that he had strayed off course.

The simultaneously sent “dot-dash” pattern would cancelled out the “dash-dot” pattern creating a solid tone to the pilot if they were on course. Anything else meant the aircraft wasn’t headed directly towards the transmiting towers.

For course corrections or to skirt mountains, a pilot could follow the frequency for Tower A (320 deg) for maybe an hour then change to the radio frequency for Tower B (350 deg) for 2 hours when the another radio frequency change would direct the plane towards Tower C (020 deg).

[doorhinge]

@Bookkeeper

The Germans actually did launch V-1s from modified Heinkel 111 bombers, but they just used the standard internal guidance mechanisms, and were likely even less accurate than the ground-launched ones.

The V-1 guidence system was adequate enough to hit a large target the size of East London or North London but it couldn’t target a particular building or even a specific city block.

[Mr_Downtown]

And the British deliberately underreported strikes south of the Thames, so the Germans kept aiming further and further south. Soon many of the rockets were striking farmland in Kent.

[Paul_in_Qatar]

Thank you all very much.