Was the Enola Gay affected by the EMP?

Question

Little Boy would have sent out an electromagnetic pulse and shouldn't the Enola Gay's electronics have been affected?

It's top speed was 360mph, and the bomb exploded 42 seconds after drop, so it would have been 40-50 miles away. I don't know how far an EMP has effect.

According to the smithsonian site there were several "very sophisticated" computer systems on board--esp the gunners' systems. Again, I'm not sure what qualified as a "sophisticated" computer in 1945.

Answer 1

Yes. The crew was ordered to shut down it's radio and some other electronics until after the blast. The motors themselves were not affected because of the type of ignition system it had. EMP effects were well documented during the Trinity test.

OK, some clarification cause I want the points. Modern electronic ignition systems are very susceptible to EMP, as are any electrical systems that contain solid state components. The Enola Gay, along with every other internal combustion engine at that time, used a mechanical (ie. points and rotor) ignition system. Take heart, after warday, your '68 Camaro may be the only thing on the roads.
Next, EMP was suggested in therory before Trinity, but the actual effects were greater during actual testing than anticipated. The only way to shield from EMP is to place your equipment in a Faraday cage. If the equipment in question is a tube radio, it becomes protected simply by turning it off.
The bomb sight was called the Norden, and while sophisticated, it was a mechanical, not electrical, device, and for that reason was totally impervious to EMP.

And more- The Enola Gay was 11 1/2 miles away when the bomb exploded. The estimated yield was 15 kT. And given the weight restrictions on the aircraft it is unlikely that a backup radio was aboard.
http://www.cfo.doe.gov/me70/manhattan/hiroshima.htm

and info from wikipedia
The aircraft that delivered the atomic weapons at Hiroshima and Nagasaki did not fall out of the sky due to damage to their electrical or electronic systems. This is simply because electrons (ejected from the air by gamma rays) are stopped quickly in normal (dense) air for bursts below 10 km, so they don't get a chance to be significantly deflected by the Earth's magnetic field (the deflection causes the powerful EMP seen in high altitude bursts), but it does point out the limited use of smaller burst altitudes for widespread EMP.
If the B-29 planes had been within the intense nuclear radiation zone when the bombs exploded over Hiroshima and Nagasaki, then they would have suffered effects from the charge separation (radial) EMP. But this only occurs within the severe blast radius for detonations below about 10 km altitude. EMP disruptions were suffered aboard KC-135 photographic aircraft flying 300 km from the 410 kt Bluegill and 410 kt Kingfish detonations (48 and 95 km burst altitude, respectively) in 1962 [2], but the vital aircraft electronics then were far less sophisticated than today and did not crash the aircraft.

en.wikipedia.org/wiki/Electromagnetic_pulse

Answer 2

This is an EXCELLENT question! Let's look at it in detail.

1) Did Little Boy put out an EMP...? Yes.

2) Was it as large as modern weapons' EMP's...? No, as it was only 10--12 Kiloton yield, and the power in the EMP would be proportionally smaller. 'Tactical' nukes theses days are in the 100 Kiloton range.

3) Were they exposed to it at close range...? No, using the 'Tokyo Two-Step' (the evasive maneuvers prescribed by their commanders) Enola Gay would have been several tens of miles away by the time Little Boy went off. Say they were 32 miles away. According to the inverse-square law, which defines the manner in which radiant energy behaves, the intensity of the EMP would have been reduced by a factor equal to the square of the distance from Ground Zero.

4) Were the electronics as radiation-sensitive as modern devices...? surprisingly, no. Properly designed vacuum tubes (which is all they had back then, this was before the invention of the transistor) are much less radiation sensitive than solid state devices.

5) Just what was the most radiation sensitive device on board the aircraft...? Well, considering that this was AFTER they had completed the most important port of the mission, it had to be the crew!

Granted, if the Enola Gay had been brought down or otherwise crashed and been captured, the films, etc., would have been important and highly classified security materiel. But, some tens of miles out at sea, or so, as we have already seen by that time, the plane would probably not have been recoverable with the methods and equipment available in that day.

6) Did they have a backup system...? I do not know, but I would guess that they probably did. It would make plenty of sense to take along a spare radio, one which was shielded in a Faraday cage (go ahead, look it up) and not even connected to power until well after the pulse.

The military is like that, trying to think of every possible contingency; and they had already had a test blast or two at Alamogordo, thoroughly instrumented so that they had an idea of what to expect. They were not going into this completely green.

So they probably brought out their spare radio AFTER their other one had been fried useless, and were able to get back on course to Tinian. A nice little island, unless you had to be stuck there for any length of time.

Keep on asking good ones like this!

Answer 3

Sure, an EMP pulse can affect even simple wiring (such as a standard car ignition).

The fact that Enola Gay returned safely obviously suggests that the craft was far enough away from the blast site, and/or that the yield of the atomic bomb did not produce a powerful enough EMP pulse.

Answer 4

When someone in my WWII class asked if the plane was affected by the bomb, my prof assured us that the plane was long gone and out of range by the time the bomb hit the ground. And I'm not a plane expert, but the Enola Gay may not have had fancy electronics to begin with.

Answer 5

first of all why did they call it the enola gay? did we drop a gay bomb on them? and second of all why was the plane not vaporized. how do we have footage of this event? would the camera film not be destroyed from radiation exposure? you cant even put film thru the machine at the airport without making it go bad. i would imagine being in the vicinity of a nuclear bomb would be much worse. the bomb vaporized anyone within 10 miles. im sure something 50 miles away would sustain serious damage from the air pressure waves alone.

Answer 6

Hi. Good question. Any computers on board would have been A) primitive by today's standards and B) already through their mission. A Russian fighter was captured (do your research) and found to have tiny vacuum tubes in it's logic circuits. The technicians who were taking it apart laughed that that was the Russian idea of miniaturization - make tiny tubes. Until a smarter guy pointed out that tiny tubes would not be effected by EMP.

Answer 7

I Think the Military was already aware of EMP because of the testing
leading up to Trinity, I Think they had developed shielded electronics plus at the speed and altitude, the plane was at and advantage as far as getting away. I hope it helps!

Answer 8

Given its altitude and distance from the explosion, its effects may have been minimal if at all.