V1s Shotdown

Discussion in 'Aviation' started by OldSkeptic, May 3, 2014.

  1. OldSkeptic

    OldSkeptic Active Member

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    I did this analysis years ago, examining the V1 shot down.
    It was an interesting exercise and when I did the numbers some surprises came up.

    Anyway the master table is:

    V1 Main Table.JPG

    But that is only part of the story. Though a total of 33 squadrons were involved against the V1s in that June - Sept 44 period only 15 served throughout the entire time.
    Many reasons for that, for example Tempest production was just ramping up and new squadrons of them were added as they were equipped.

    If we look at the squadrons that served through the whole period we get:
    V1 Table Full Time.JPG

    The Tempest numbers include the FIU a flight of which also worked at night. All the Mossies (inc the VIs) worked at night.

    The raw data is:
    V1 Master Table.JPG


    The amazing thing is how well the Mossies did, despite their slower speed compared to the Mustangs, Spit XIVs and Tempests.
    Part of that was the tactical situations. At night a V1 was very easy to see so they typically flew higher, saw one and dived down.
    On the other hand, flying flat out low down at night was fraught with danger and the pilots were blinded by the light from the V1, very tricky stuff indeed. So by no means did they have an easier job than the day fighters. 418 squadron with ancient Mossie Mk IIs did amazingly well considering how old and clapped out their planes were.

    The Mustang's relatively poor performance (despite their incredible low level speed) was caused by several factors:
    The Mustang squadrons also did escort work (for day British bombers) so were not involved every day. The pilots were a bit cagy about hammering their engines (the Packard Merlins were more lumpy than the Merlins at 25lb boost) since the next day they might be going on a long range escort job, can't really blame them. The Mustang guns were not as good against V1s (remember they were Mustangs IIIs = P51Bs with only 4x0.5") as the heavier cannons of the Spits, Mossies and Tempests. V1s were quite tough, with very few moving parts and of course hard to hit because they were so small.

    The Spit IXs did surprisingly well too, but they must have been hammering them real hard, at that altitude they were not in the class of the Tempests, Mustangs and Spit XIVs. The Spit XII squadron did well too, considering that their planes were also getting pretty long in the tooth by then and the version of the Griffon they had couldn't be extra boosted, so their performance was just base original.

    Tempests were cleared to 9lb boost (11lb boost came much later), Merlins (RR and Packard) to 25lb and the Griffon in the Spit XIV to 21lb boost. The later mark Mossies used Merlin 25s cleared to 25lb boost too (though the older ones were still limited to the 14-18lb boost range depending on the engine model). All the planes were cleaned up as much as possible and many weight reduced as far as practical.
     
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  2. Mike Williams

    Mike Williams Active Member

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    Nice work. Fwiw, 350 and 402 Squadrons, equipped with Spitfire XIVs, destroyed V-1s during the latter half of August 1944 (350 - 6; 402 - 5). They weren't full time on anti-diver duty as they flew many offensive missions over the continent as well.

    Tempest Vs were operating at +11 lbs with ADGB during the summer of 1944; see here.
     
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  3. Wildcat

    Wildcat Well-Known Member

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    Great info, very interesting indeed!
     
  4. OldSkeptic

    OldSkeptic Active Member

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    #4 OldSkeptic, May 3, 2014
    Last edited: May 3, 2014
    Good point thanks for that. Yes they did 11lb and had problems but it was acceptable for the V1 campaign, then went back to 9lbs for operational use, then later 11lbs with the Sabre IIb (which, from memory had a strengthened supercharge quill).

    Yes I probably have missed some of the short 'part time' squadrons, but I think I've got the major ones. But if anyone has any more info please post and I will update my database. I've added 305 and 402 to my tables.

    Thanks Mike.
     
  5. nuuumannn

    nuuumannn Well-Known Member

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    Two were shot down by FAA Grumman Avengers over the Channel in separate incidents. I only have details on one of them though. An 854 Sqn Avenger II shot one down on 9 July 1944. Gunner Fred Shirmer shot at the V 1 off the aircraft's port beam at a range of 700 yds, expending only 20 rounds of ammunition from his rear turret gun.
     
  6. Aozora

    Aozora Well-Known Member

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  7. parsifal

    parsifal Well-Known Member

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    Nice work, well done
     
  8. Koopernic

    Koopernic Active Member

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    #8 Koopernic, May 5, 2014
    Last edited: May 5, 2014
    This is excellent work.

    From your primary data is it possible to work out success per sortie or success per attempted intercept on a time basis, is that available?

    I am curious as to whether V1's became more difficult to intercept.

    The A4 (V2) and the German, Soviet and American Rocket Program By Claus Reuter notes the following about Fi 103 speed.

    Reuter was an engineer on both the the A4 (V2) program and V1, his connections are mainly engineering not operational. This is a quote from his book.

    "Further development of the Fi-103 was pushed ahead to improve the speed to give the Fi-103 a better chance against attacks by enemy fighter aircraft.
    The improvement of the fuel regulator increased the speed of the Fi-103.

    The following speed-increases were achieved:
    Spring 1943 600 km/h (372mph)
    Summer 1944 645 km/h (400mph)
    Autumn 1944 765 km/h (474mph)
    January 1945 795 km/h (493mph)
    The increase in speed made the Fi-103 substantial faster than most of the enemy fighter aircraft. It would
    mean that the downed Fi-103’s were mostly the early production models."

    Given the claims it appears that at least as far as R+D goes a V1 with a speed of 474mph goes was producible around November 1944 and it conceivable they might have been launched from that time onwards. Those sorts of speeds clearly knock out the piston engined aircraft and likely also the Meteor III and P-80A.

    Reuter goes to pains to explain that the improvements did not involve changes to the Argus engine or the airframe, this was a simple fuel system only modification.

    He continues:

    "Fliegerstabsingenieur Friedrich Graf von Sauma and his brother Hans Harald were instrumental in the
    further development of the Fi-103. Both worked on the aerodynamics of the Fi-103 and improvements were
    made. Ten of the improved versions of the Fi-103 reached speeds of 830 km/h. {505mph}. Besides the improvement in
    speed the range was also increased to 350 km. Planned was a version with a range of 500 km. Because of the
    short life span and high fuel consumption of the Argus pulsejet power plant a proposal was put forth to
    approach BMW and Porsche to develop a new turbo jet power plant for the Fi-103. The development work
    on the new power plant was not completed by the end of the war."

    It's worth noting that range increases in the V1 were achieved both by engine improvements, an introduction of a long range version with a reduced warhead and finally there were plans for a disposable turbojet variant. The turbojet variant would be the BMW and Porche 109-005 mentioned in Anthony Kay's book on German jet engines. It sounds a little far fetched to make a cheap turbojet but remember the Germans had developed ways of stamping turbine blades out of sheet metal and automatically welding them.

    It's worth noting that the V1 was to receive a guidance system called "Ewald II". In this the V1 sent out a pulse which was received by three ground stations. The timing difference was used to calculate the position of the missile and corrections sent to a device called "sauerkirsche". Because the Ewald II unit was not a transponder replying on an interrogation it was expected to be extremely difficult to jam. The receiver used not FM or AM modulation but impulse modulation which was decoded by an endless loop tape. To avoid the possibility of jamming this was a 'mid-course' correction system and accuracy was expected to be 2km if the correction was done less than half way, obviously the closer to target the correction then the more accurate it would be. It would have been essential for the longer range V1's. This system actually got to the point of building the ground stations and testing.

    Many V1's had a transmitter called Ewald I on board. When data from these started reporting hits different to what was being received from supposed spy's in London the Germans ignored the electronic data as random divergences. We now know of course British double agents were feeding the wrong impact data.

    Eisenhowers statement that the V1 campaign might have disrupted Overlord enough to stop the invasion had it started a few months earlier certainly seems correct to me.
     
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  9. Koopernic

    Koopernic Active Member

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    #9 Koopernic, May 5, 2014
    Last edited: May 6, 2014
    It's possible if the Avengers turret was equipped with lead computing gyro gun sight which would have incorporated corrections for range, air speed etc. The USN was very good at developing this sort of technology despite their stuff up with torpedos.

    Just checked around, British turrets could use the Mk 11c gyro gun sight, US ones something called the Mk 18. Maybe Defiants would've worked. Certainly gets around the problem of the interceptor having to be faster than the V1.
     
  10. michaelmaltby

    michaelmaltby Well-Known Member

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  11. bobbysocks

    bobbysocks Well-Known Member

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    i am actually surprised the mustangs got that many....for many of the reasons you said.
     
  12. OldSkeptic

    OldSkeptic Active Member

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    You are right, they did very well given the circumstances.

    Three of them were Polish squadrons and we all now how good they were. 306, 315 316 squadrons.
    The other, 129 squadron was a very experienced one. All of them had similar scores:
    129- 66
    316 - 74
    306 - 60
    315 -53

    The RAF worked it's Mustang squadrons very hard as they were so useful for so many tasks and they never had enough of them.
     
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