V-1 and V-2 - what's the difference?

V-1 and V-2 bombs (or rockets?) have come up tangentially in a few threads recently, so I thought I’d ask a few questions about them.

What’s the difference between them?

How effective were they as weapons?

Could they have ever made a difference in WWII, if introduced earlier? (I would have thought that since Britain was able to survive the Blitz, with bombs being dropped by airplanes, that the V-1 and V-2 wouldn’t have had much of a different effect.)

V1—cruise missile, jet engine, small(er) warhead.
Cheap, inaccurate. Lad launched, sometimes air launched.

V2–medium range ballistic missile. Big warhead. More accurate. Pricey. Land launched, plans for submarine launches (never carried out).
Both had numerous failures on launch, both built in concentration camps, with slave labor.

The V-1 flying bomb was a pulsejet-driven missile that burnt petrol and atmospheric oxygen.

The V-2 was a ballistic missile that burnt ethanol using an internal supply of liquid oxygen.

The V-2 was more expensive and heavier, but it was a lot faster and basically impossible to shoot down.

Neither weapon was particularly effective. The British quickly worked out a system for shooting down the V-1, fast fighters, including jets, to intercept the missiles at long range, and guns with predictors to shoot down those that got close to the target.

The V-1 was fast and small, so shooting it down was difficult but it couldn’t dodge out of the way so the fighter pilots soon learnt to get in close to guarantee a kill. The biggest danger to the fighters was that they were shooting at a bomb at close range and could be brought down by the blast.

The V-1 was also originally launched from fixed ground launchers but the RAF and USAAF soon destroyed the fixed sites so that the Germans had to developed mobile launchers, both ground based and aircraft based.

Strategic bombing was shown to be a huge waste of resources in WW2. Britain survived the blitz without much trouble but still believed that bombing Germany was a good idea. By the end of the war German cities and industry were being hit by massively powerful bombing raids almost daily but Germany still managed to increase production despite the bombing.

If the Germans had managed to attack Britain with the V-1 and V-2 weapons earlier in the war the effect on the outcome would have been negligible. The US factories were still safe from attack and bombs on London would do nothing to stop the biggest threat to Germany, the Soviet Union.

The revenge weapons schemes led to some amazing technical achievements, the V-2 was the first ballistic missile but was built before computers were available for guidance, but diverted resources away from projects that were more practical in the short term.

Thanks for the replies.

Follow-up question: What’s the difference between a pulsejet-driven missile and a ballistic missile?

The pulse-jet driven V1 was a small pilot-less plane with wings that flew straight and level at about 400mph and 6000 ft from the launch site to the target. The V2 - any ballistic missile - is powered by a rocket motor that powers it up and out of the atmosphere, it then travels in a parabolic ballistic arc until it falls almost vertically on the target at many thousands of miles an hour.

As already noted, one you could shoot down in 1944, the other we still can’t reliably stop.

In simple terms, one is a bomb with wings and a jet engine on top, which flies in a straight line until it reaches its target (and then dives); the other is a proper rocket that travels in a parabola to its destination.

Here are wiki links showing the design of the two rockets.

V-1, V-2.

There was also a manned version of the V-1 built in order to improve accuracy, the Fieseler Fi 103R.

3-view pic

This was not technically intended as a suicide weapon because the pilot was to attempt to bail out after entering a dive. The problem was that the intake was directly above the cockpit and made bailing out almost impossible.

The V1 was also called “the buzz bomb” because of the distinctive loud buzzing noise the pulse jet made; my understanding was that you could hear it coming from a significant distance, and with its modest speed, people had enough early warning to seek cover before impact.

OTOH, the V2 rocket, in the terminal/descent phase of its flight, was supersonic; people at the target site had pretty much zero advance audible warning of the approaching missile.

In fact with the V1 as long as you could hear it you were alright. The way it worked was it droned along for a pre-calculated period and then the fuel to the jet was shut off. At this point it spluttered, the engine stopped, and it dived into whetever was underneath it. So people had only seconds to find cover once the noise stopped.

With the V2 nothing was heard until it hit the ground and exploded - then there would be the sound of the sonic boom arriving after the actual missile.

Do some internet research on pulse jets and ram jets.

They are exceedingly simple. Its a tube, that you pour fuel into and you get thrust out. Its something the Egyptians could have built. Real jet engines and rockets not so much.

The only real downside to a pulsejet is that they suck fuel down like a factor of 10x or more than even a crappy jet engine for the same amount of thrust. But if you arent flying very far or can’t crank out jet engines fast enough, a pulse jet makes sense.

I’ve got an old one in the garage. It wieghs just a few pounds, is about 2.5 feet long, a couple inches in diameter and IIRC has a 10 pound thrust rating. I hesitate to fire it up here because they are SO damn loud I have no doubt someone would call the fire department post haste.

Actually, the V-1 was supposed to go into a power dive. It was a design flaw that caused the engine to cut out when it tipped into the dive. This flaw was fixed in later models of the missile.

A few technical caveats.

The V-1 and the V-2 had almost the same sized warheads – 850kg vs 980kg. There wasn’t a significant strategic difference in the size of the explosion. The range wasn’t orders of magnitude longer for the V-2, either, at least as far as wartime development got – 250km vs 320km.

Both were fired blind over-the-horizon, because Germany had lost control of the skies and couldn’t use spotter or photorecon aircraft to judge where the V-weapons were landing. In practice, they used spies to find how accurate the weapons were…but the British had turned them into double agents, who sent the Germans reports that they weapons were landing beyond London, causing them to progressively shorten the range. The weapons began falling short of London into (theoretically) less valuable areas.

The principle difference between the two in strategic terms was that the V-1 cost 3500 reichsmarks and the V-2 cost 100,000 reichsmarks; you could launch twenty-eight V-1s for the cost of every V-2. That means that in cash terms, the V-1 carried 23,800kg of warhead to the V-1’s 980kg. “Heavier warhead” can be calculated in more ways than one.

Of course the V-2 technology held the promise of eventually reaching America with stages added (which was being planned, albeit in a pie-in-the-sky kind of way). Historian John Keegan has written that the prospect of such a weapon carrying a theoretical Nazi atomic bomb is the most dire possibility of WWII that never came to fruition.

It’s been said that had the Germans conserved V-1s and used thousands of them in a single massed attack against the cross-channel invasion fleet it would have been devastating, but this has always seemed iffy to me. You can’t hit a moving fleet with V-1s, and (as unguided area weapons) they’re ineffective against a dispersed fleet, so you’d have to hit the fleet just as it assembled for the crossing. Timing and aiming such an attack would certainly have required the aerial reconnaissance Germany was already unable to muster.

I hadn’t realised that. I knew the mechanism was meant to tip the V1 into a dive but I thought cutting the fuel supply at the same time was deliberate.

The fighter pilots eventually tried to get around this by flying parallel to the bomb and then slipping one wing under one of the bomb’s wings and flipping it over. Unpiloted, the bomb wouldn’t correct its attitude and would crash (somewhere uninhabited, they hoped). This method was also dangerous and tricky but at least the bomb wouldn’t blow up right in front of your plane. I don’t know what proportion of pilots opted for this method.

The radar proximity fuse made anti-aircraft shells MUCH more effective, and proximity fuses were issued to English coastal AA batteries as a priority. This greatly increased the number of V-1s brought down from ground-based AA. Note that the V-2 was immune to both these forms of interception, and would remain so until the Patriot Missile batteries began trying to shoot down Scuds in Iraq (and that itself was apparently less successful than was first thought).

To give an idea of the usefulness of the V1 and V2 as a weapon system keep in mind that by 1943 the RAF alone could deliver over 2000 tons of bombs to a German city in one night. The Germans only managed to launch 10000 or so V1s - with their less than 1 ton warhead - in the whole campaign and a very large proportion of those got nowhere near their target. The V2 was even worse, a bit over 5000 were launched but only about a fifth of these reached Britain.

In their own ways both weapons were terrifying to the civiliam populations and they did cause casualties but there was absolutely no chance of them altering the course of the war. As **Sailboat **say with regard to D-Day, these were area weapons and terribly inaccurate - they could have caused damage but not stopped the invasion.

Of course, accuracy doesn’t matter when you’re a patriot. :rolleyes:

IIRC too - the V2’s were pretty heavy and needed a good solid stable launch pad. One thing the allies did was find and bomb launch sites. I read that the Germans would eventually counter this drive up to a precalculated launch location, pour liquid air on the ground to create a solid footing, and launch before it melted.

This meant more fun for logistics - now you need liquid air (LOX for th engine anyway).

Another difficulty wa calculating winds aloft to ensure the very primitive electromechanical guidance was set properly.

One reason this might be coming up a lot is that the new Connie Willis book has a lot in it about the Blitz and the V-1 and V-2 attacks.

I have a footage of the portable launching pad that was developed and used for the V-2. A convoy that included the semi-rig towing the missile as well as a vehicle carrying the launch platform and the fuel trucks and launch personnel transports would travel out to the predetermined point for the launch. It was a process that took quite a while due to assembling the launcher, mounting the missile, fueling, etc… but was still safer than any kind of fixed platform.