Mistakes in Aviation

I think its worth remebering that the later Meteor III had the changes to the Nacells which significantly improved the speed of the aircraft making it a match in speed at least to the 262.
Also had the war continued I am confident the Mk IV would have been in production well before 1947. The basic design was very similar and no real difficulties would have been expected.

There is no doubt that the lack of suitable raw materials hindered the production of reliable engines for the 262 or any other German jet.

Hello red admiral,

Unfortunately I do not have my Kurt Tank book with me, but I do recall the figure of about 1300 scientists, researchers, engineers and skilled workman from FW were entertained by the Russians, compared to about 25 in Argentina.

I also do not think that it has much to do with just copying existing German features (maybe to a small fraction) but having the extensive research protocols and evaluations of those features by a/c manufacturers which in turn had a significant impact on the timeline of the future development of a/c in any of the allied countries for the period of 10-15 years after the war.

E.g. variable geometry wing design wasn't even dreamt about in any country besides Germany before 1944. That the US managed to modify and improve on it is understood since Germany didn't exist for the next 4 years and had to rebuild its ruins for another 10 years.

So indeed I could forward that the F-111 is based on the experience and data collected through a XF-10F and Bell X-5 via a Me P1101. After all Bell had 6 years time to improve the Me P1101 developing an in-flight "variable-geometry" platform.


Regards
Kruska

Pfft, by the time the F.4 had been with combat units (late '45 at earliest), one of the HG versions of the 262 would've been ready. Even without improved engines it would've been a match and with newer versions of either jumo 004 or bmw 003 who knows how capable it would've been. The airframe was competetive until the late 40s at least and it's not like airframe development would've stopped.

BMW 003s were not only used in the MiG-9 but also were also developed into the Atar, which still powers the aircraft of several airforces to this day, so yeah there was tremendous potential. The Meteor was simply inferior.

Going from P.1101 that didn't really have variable sweep wings, 10° change in angle and even then only on the ground, to the F-111 is a huge step and neglects the fact that the F-111 didn't really work very well. Another advocate of variable sweep wings was Barnes Wallis postwar with Wild Goose and Swallow projects. These were extremely advanced using only the wings as control surfaces with no tail or ailerons. The model built worked reasonably well on test flights before being cancelled from finanicial issues. Even so, variable geometry wings for such a small aircraft are a bad idea. Something slighter larger than the Tornado is the break-even point (the Tornado needing VG for landing restrictions)

one of the HG versions of the 262 would've been ready.

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The HG II and HG III performance projections are completely ridiculous, especially for the HG III. Those performances weren't achieved for another decade and even then with hugely more powerful engines and a lot less drag from research in between.

The Atar is not the BMW 003 (which was a pretty good early axial engine actually. Probably second best behind the Metrovick series of the early efforts). Theres a large step between being the same and having the same arrangement.

The Meteor was simply inferior.

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The I, II and III series of prototypes yes. The first acutal fighter version, the F.4 was superior to the Me 262 except in the rolling plane.

So you want to seriously tell me the Atar 101 isn't a direct evolution of the 003 and essentially a scaled up version of the latter? Despite being developed by pretty much the same team of German engineers? Do you know what the R in ATAR stands for? I assume the CETME is also not a descendent of the Stg-45 then?

And the projections for the HG didn't even have to be remotely true to be competitive or superior to the F.4, especially not with a new iteration of the 004 or 003. Given the pace of evolution of aircraft and (jet) engines at the time, to think that by late '45 there would not have been a second generation of 262s (which was only in the infancy of its lifecycle) available, especially with the evidence of its progress readily available, is just kidding oneself. And late '45 is a very optimistic guess for first operational use of the F.4, too, considering the maiden flight of may that year.

The airframe of the 262 was more progressive than that of the Meteor and the underwing engines, while aerodynamically inferior, made adaption to new engines pretty easy.

Admiral the Mk.I was the Meteor to fight V-1's (albeit somewhat unsuccessfully due to the jamming problems with the cannon)

The Mk. III was the one to go on strafing missions over Germany in the last weeks of the war. (note, initially with short nacelles only ~20-30 mph faster than the Mk I, with long nacelles it did ~520 mph with Derwnt I's)


And the advantage of the 004's axial compressor was to reduce frontal area and improve aerodynamic efficiency, not fuel efficiency. Granted it was a conservative design (kind of a conservatively advanced design) intended to reach production in the shortest possible time, however problems with switching to non-strategic materials delayed production by ~2 years. (due mostly to the vibration problems along with some development time for air cooling, not solved until the 004D, which could overrev to 10,000 rpm and produce 1050 kp alo with TBO increasing to ~60 hr)

The air cooling developments were certainly an advanced feature though. And SFC was only ~20-30% worse for the 004B-4 than the Welland or Derwent I.

The 003 was a considerably better design though (the annular combustor, made largely of mild steel, lasting over 300 hr in testing) much more compact and lighter than the 004, though heavier than the Whittle engines, and more fuel efficient than the 004. The 003E producing ~920 kp with overrev, and a redesigned 003D (featuring a reaction compressor) producing 1,200 kp with little increase in weight or fuel consumption. (and thus specific fuel consumption went way down)


And there's the HeS-30 which cancelled in possibly the worst mistake in German jet development in the war. Weighing about the same as the Welland and producing up to 910 kp in testing, it utilized the more efficient reaction type compressor (opposed to the impulse blading of the 004) and produced about the same compression ratio in its 5 stage compressor that the 004 did in its 8 stage one, with 10 can-type combustion chambers, and a diameter of ~24 in, and excellent specific fuel consumption. (overall performance compared to weight, frontal diameter, and fuel consumption not exceeded until the J34 or MetroVick F.2/4 of the late very end of the 1940's)

The only difficulty with this design was that the compressor blades required machining and rotors used thrust bearings, opposed to the simpler blading of the 004 which were made of stamped steel.



And while the performance estimates were inflated for the HG-II/III they still would have been comparable to the Korean War era a/c if fitted with uprated engines (in the 3000 lbf thrust range), I don't see why high transsonic speeds wouldn't be possible (.96 Mach at alt planned for the HG-III) as the F-86 came fairly close to that (~.92 iirc) at best altitude with relatively little thrust. It would certainly be capable of a supersonic dive. (as would the HG-II, thought the engines would flame out due to the outboard placement with intakes resulting in compressor stall due to shock wave)

So you want to seriously tell me the Atar 101 isn't a direct evolution of the 003 and essentially a scaled up version of the latter?

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There was quite some progess between 1943 and 1946 in addition to extra resources at SCNECMA's disposal. It would not be possible to develop the Atar for German use in the timeframe because the effort was going into making the 003 work. The 003 was a good engine, considerably better than the 004. The Metrovick series were better, offering greater reliability, more power and less weight. This engine was developed into the AS Sapphire with pretty much the same design team. The Sapphire is not the same engine as the F.2 series, coming later after the problems (not many actually) with the F series had been found.

Given the pace of evolution of aircraft and (jet) engines at the time etc.

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003 and 004 are maxing out at about 2300lbf. The new engine available in the time frame was the Hes 011 which never came close to making its designed thrust postwar. There weren't more powerful engines available for the Germans. Comparatively, the Nene and Derwent V had just been tested in the UK in addition to already more powerful Goblin. The difference in speed from the HII derivative is minimal, even going with the predicted performance. The M0.96 figure for the HG III is based on flawed data that effected all the fast Luft 46 planesThere was insufficient data for proper estimation in the transonic range, and no research to get any.

The wing sweep on the Me 262 was adopted for balance reasons, not aerodynamic. The 18° sweep puts up Mcrit by an entire 0.01. With the longer nacelles, both the Me 262 and Meteor were limited to around 0.81-0.82. The conception that the Me 262 was more advanced is flawed because all people fix on is the fact that it has swept wings. So has the C-47.

Admiral the Mk.I was the Meteor to fight V-1's (albeit somewhat unsuccessfully due to the jamming problems with the cannon)

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The Mk I fought over the UK. The Mk III fought V-1s over Antwerp and did ground strafing, being ordered not to fly over German lines.

And while the performance estimates were inflated for the HG-II/III they still would have been comparable to the Korean War era a/c if fitted with uprated engines (in the 3000 lbf thrust range), and didn't the HG-III incorporate area rule into the design? (which would allow excellent speed with even underpowered engines, possibly supersonic with adequate engines)

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I very much doubt it but as they were never built its rather hard to get a definitive answer. The early F-86 wasn't that much faster than the Meteor F.4 but the swept wings allowed for a higher Mcrit which means diving speed and more control. There was no area rule on the HG -III, it had yet to be invented. Actually, it does completely the opposite of what area ruling requires with a very large change in area because of the fuselage mounted engines. Mcrit might stay similar to the HG-III despite the extra wing sweep. The only way the design is going supersonic is vertically towards the ground or with a huge honking rocket attached.

Yeah I edited my post on the area rule thing, however area rule did exist:

The area rule was first discovered by Otto Frenzl when comparing a swept wing with a w-wing with extreme high wave drag [1] working on a transonic wind tunnel at Junkers works in Germany between 1943 and 1945. He wrote an inventor message on 17 December 1943, with the title "Arrangement of Displacement Bodies in High-Speed Flight"; this was used in a patent filed in 1944.[2] The results of this research were presented to a wide circle in March 1944 by Theodor Zobel at the "Deutsche Akademie der Luftfahrtforschung" (German Academy of aeronautics research) in the lecture "Basically new ways to increase performance of high speed aircraft." [3] The design concept was applied to a variety of German wartime aircraft, including a rather odd Messerschmitt project, but their complex double-boom design was never built even to the extent of a model.

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On the HG-III agree it wasn't going supersonic w/out a steep dive.

But what about the HeS-30 (006) I mentioned, and the 003 topped out at 1,200 kp (2643 lbf) in the 003D with reaction compressor. (same type as the HeS-30)

And the 004E produced 1,200 kp with afterburner (1,000 kp dry w/out overrev, in in testing with overrev 1,100 kp dry) and in post war development as the RD-10 the RD-10F (developed 004E) produced 1,100 kp thrust dry in production models.

One other thing that I forgot to mention was that, while the Me 262's ~18.7 degree sweep was primarily for CoG issues (though it did help a little), the Me 262 did use some advanced aerodynamic features.

It used a thin (11% root 9% tip TR) low drag airfoil with full span automatic LE slats and relatively thin (somewhat swept back) tail surfaces with an electrically operated variable incedence tailplane. (for trim, also useful for recovering from dives) Giving the a/c a critical mach number of .86 in Messersmitt testing and giving excelent high speed control characteristics.

One flaw, however, was a lack of airbrakes and thus it could not regulate speed (particularly in dives) like the Meteor or P-80. (I can't remember if early Vampires featured airbrakes)

This is obviously turning into another pointless battle of will that seem common here, so I will leave you to your opinion even though I think you base them on wishful thinking rather than trying to be objective. You are comparing an aircraft that didn't become operational until 2 years after the war to one that was available in mid to late '44 and assume that it would make it in time to be operational in numbers by late '45 (wishful thinking) and that it's potential enemy in question would've remained the exact same, eventhough evidence of its progress is plentiful. You also tell me, contrary to the all the books I have read on the subject, the developments of the 003 are in fact not (despite having the same German design team, which you continuously ignore), maybe you ought to contact some aviation historians and tell them they're all wrong.

Mistakes in aviation?

Big one for Fonck and Sikorsky was turning the S-35 from this...

View: https://www.youtube.com/watch?v=3gJKLpQDOKI

KrazyKraut said:

This is obviously turning into another pointless battle of will that seem common here, so I will leave you to your opinion even though I think you base them on wishful thinking rather than trying to be objective. You are comparing an aircraft that didn't become operational until 2 years after the war to one that was available in mid to late '44 and assume that it would make it in time to be operational in numbers by late '45 (wishful thinking) and that it's potential enemy in question would've remained the exact same, eventhough evidence of its progress is plentiful. You also tell me, contrary to the all the books I have read on the subject, the developments of the 003 are in fact not (despite having the same German design team, which you continuously ignore), maybe you ought to contact some aviation historians and tell them they're all wrong.

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KK already forwarded my thoughts in regards to these always repeating endless discussions between Allied developments after WW2 in contrast to finished and partially in action proven German developments before 8th May 1945, endlessly referring to "if", "when, and "could, "would" and ending in mathematical, aerodynamically concluded statistics, stall, wing design, flaps, airbrakes and inferior burned out German jet engines.

Allied jet a/c developments before 8th May 1945: and their numbers in action on the field

Meteor F1 (20-30)?
Meteor F3 (20-30)?1 Squadron)
Vampire MK I ( 0 )?
Airacomet (6? Came to Italy)?
P-80 (4 a/c, 2 to England, 2 to Italy)

German jet a/c developments before 8th May 1945: and their numbers in action on the field

Ar 234B (80?)
Ar234C ( ? )

He 162 (60?)
Me 262 (400?)
Me 163 (80?)

So this comparison discussion is based on the "experience" and "flight/combat" evaluation of approx. 50-60 allied jets in operation (who downed in air combat about (1 Fieseler Storch ?), - okay let's not forget about the 14 V1's, in contra to 600-700 German jets in operation that downed in air combat about (400-450?) a/c.

So I might end my post by forwarding that the "Wasserfall", "if" pushed, instead of the V2, "could" have devastated the Allied Air forces in conjunction with the German jets (no matter how fantastic the British jet engines where), and "would" have changed world's history at least until August 1945.

So IMO the neglect of the "Wasserfall", "Rheintochter" and "Enzian" are the biggest German mistakes in aviation and not it's "inferior" jet engines.

Regards
Kruska

Though the Me-262 HG-I was built and flown (swept tailplane, low profile canopy, and 35 degree sweep added inlay inboard of nacelles) and the HG-II was built, but not flown (destroyed iirc) featuring swept tail (V-tail origninally planned) and redesigned wings with 35 degree sweepback.

I'm not sure, but I don't think the HG series was even close to production, and I'n not sure on the considerations to produce it either. (more experimental)

I think an improved 'standard' Me 262 with maybe minimal improvements to the airframe would have been more concevable. With 2,300-2,450 lbf 004D/E engines with improved handeling, reliability, service life, altitude performance, and fuel efficiency. (note I don't consider the afterburning versions with over 2,600 lbf) Similar to the improvements made on the P-80, Vampire, and Meteor.



Of course there's still the HeS-30 (006) to consider as well but who knows... (in light of this as well as the problems with the 011, I think the 011 should have stayed on the Drawing board, and Heinkel-Hirth focused on the 006, possibly with the 001/ HeS-8 as an intrim/alternate)


And the BMW 003D with 1,200 kp thrust (2,645 lbf) with new compressor (reaction blading like the 006) and greatly improved specific fuel consumption. (actual consumption similar to 003A/E at similar RPM, so 20-25 % reduction in SFC) Note the 004E produced ~2030 kp with overrev. (rated for 30 sec max in combat at full overrev)

One problem with the 003A/E actually produced is that, unlike the 004, it couldn't be restarted by the pilot after a flameout. (a serious consideration, even though flameouts were somewhat less likely than on the 004B)



I don't think it's wishful thinking for the Meteor 4 or Vampire to come online before the War's end, particularly seeing the 2-year delay with rover and the relatively low priorety of the Vampire. Even as things went the Derwent V was coming on line and the Meteor 4 could have probably been in production by mid '45 if pushed. Without the Rover problems an equivelent a/c to a late model Meteor III (long nacelles) with Derwent IV (or W.2/700) engines could have been in service by late '44. (Top speed probably ~560 mph climb ~4,500 ft/min)

kool kitty89 said:

I don't think it's wishful thinking for the Meteor 4 or Vampire to come online before the War's end, particularly seeing the 2-year delay with rover and the relatively low priorety of the Vampire. Even as things went the Derwent V was coming on line and the Meteor 4 could have probably been in production by mid '45 if pushed. Without the Rover problems an equivelent a/c to a late model Meteor III (long nacelles) with Derwent IV (or W.2/700) engines could have been in service by late '44. (Top speed probably ~560 mph climb ~4,500 ft/min)

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Hello kk89,

I also don't think it would be wishful thinking for the He290 and Me262 entering full operational status as front line fighters in their hundreds by Jan 1943 and thousands by Jan. 44.

Due to a far better resources situation before 1943 the engines would have shown a far better quality and due to more or less non-occurring allied bomber flights over Germany (Due to the jets) the continuation of further developments would have massively progressed.

These improved versions would have contributed massively on the eastern front since Wasserfall, Rheintochter, Enzian and Fliegerfaust would have taken over the majority of air defense against whatever allied prop. or jet a/c.

Regards
Kruska

I think we're at cross purposes between reality, best case and fantasy.

The LW could have had the He 280 in service in 1943 with large scale service in 1944. Masses of new materials and labour resources aren't going to fall from the sky. The He 280 is good enough to shoot down lots of the 8th AF but is quite limited for later development. However, it is available early and it works. I'm not sure whether 003s or 004s could fit onto the airframe but i'd expect Mcrit to be the problem at around 0.80. Not much can be done to get the Me 262 into service faster, with the introduction of the He 280 it would probably take longer to come into service, but would be better than historical with pilots more familiar with jets. The Atar is not going to suddenly spring from nowhere, uprated versions of the 003 and 004 appearing in late 44 to early 45 are the best hope giving up to 2500lbf but still with problems.

The stuff about the German SAMs is rather fanciful given that they didn't actually work. It took until 1953 to actually get a working SAM into service. You could probably get a more limited missile into service in early 1945 with the capability to hit in the middle of a 1000yd wide bomber formation buts thats about it. Even then you've got the problems of producing enough of them and having the launch sites shot up.

For the Meteor, the problem was the availability of engines because of the choice to go with the Power Jets/Rover design. Having a Power Jets/RR partnership accelerates the program by two years, proably around 18months when talking of service dates. So F.I in service in early 1943 with 1943 being a development year and shooting down a few V-1s. Then in early 1944 there are a bunch of options because of the longer nacelles improving Mcrit and the more powerful engines available;

1. Historical Meteor F.III with long nacelles and Derwent Is more than equal to He 280 and slightly inferior to Me 262
2. Meteor F.III with clipped wings improving speed
3. Meteor with Goblin engines in slightly larger nacelles giving around 560mph, 7000fpm
4. Meteor with W.2/700 engines (2500lbf) for around 550mph, 6000fpm
5. Meteor with Metrovick F.2s giving 2500lbf in underslung nacelles, around 570mph, 6000fpm

Around late 1944, early 45 there are a few more options;
6. Meteor with uprated Derwents
7. Meteor with Metrovick F.3 or F.5 turbofans giving 5000lbf. Speed limited by Mcrit so around 610mph max, 10-11000fpm rate of climb, range more than doubled

red admiral said:

The stuff about the German SAMs is rather fanciful given that they didn't actually work. It took until 1953 to actually get a working SAM into service. You could probably get a more limited missile into service in early 1945 with the capability to hit in the middle of a 1000yd wide bomber formation buts thats about it. Even then you've got the problems of producing enough of them and having the launch sites shot up.

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Aha, who say's they didn't work.?

The Wehrmacht ordered Rheintochter already in 1942. Starting in August 1943, 82 test firings were made. An air-launched version was also designed. Wasserfall already existed in 1943 but was not pushed. The guidance systems where in its initial stage of already working, a new system known as Rheinland was under development. Rheinland used a radar unit for tracking the target and a transponder in the missile for locating it in flight, read by a radio direction finder on the ground). A simple analog computer guided the missile into the tracking radar beam as soon as possible after launch, using the transponder to locate it, at which point the operator could see both "blips" on a single display, and guide the missile onto the target during night as during the day.

Steering during the launch phase was accomplished by four graphite rudders placed in the muzzle of the combustion chamber, and (once high airspeeds had been attained) by the four air rudders mounted on the rocket tail. Commands were sent to the missile using a modified version of the "Kehl-Strassburg" later proven by the sucessful Hs293.

Enzian could be started of from a 88 lafett mounting, and the Fliegerfaust already existed in April/May 45

Feuerlilie25/50 already got off as early as in 1941

A 306 kg warhead from a Wasserfall would indeed have been enough destructive power even within a 1000 yards diameter. The V2 was actually a very exact weapon, it is due to misinformation and choice of targets that gave the V2 the image of a blind fired inaccurate weapon.

Ragar guided V2's actually could hit targets within a range of 20m. So the technology was there it was not fantasy it existed.

"IF" Wasserfall and Co. would have been given priority, they "would" indeed have stopped the allied bombers. No one needed a guided Missile that actually slamed into the target in 43/44 or 45 due to very low speeds (400km/h) of the bombers, a close proximity fuse at 100m with a 300kg liqiud explosive warhead would have desintigrated or blown of 2-4 bombers at ease.

Have a look at EMW Wasserfall Luft '46 entry it is quite interesting;

Costing for a V2 was estimated at 100,000 RM/pc, a Wasserfall at 8000/pc.

Last not least, even though not a SAM, the R 4/M "Orkan" did its job perfectly and was IIRC already developed to a useful stage in 1940.

Regards
Kruska

Aha, who say's they didn't work.?

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Pretty much every source on the subject. Infrared guidance wasn't developed enough to be accurate. The MCLOS system mostly used could be easily jammed as with the Fritz-X guided bombs. The other guidance system was beam riding, which didn't succesfully work until the 50s with SAMs like Terrier. There were no German radar proximity fuses either, which would massively hinder any system.

The effectiveness of a system like Fliergerfaust is questionable considering the lack of trials with the system.

Radar guided V2's actually could hit targets within a range of 20m.

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You've got to be kidding. V2s were not radar guided. They were simple ballistic missiles with a primitive intertial guidance system. The CEP of the prototypes was 4.5km rising to 12km with acutal firings. The very few missiles fired with radar beam guidance managed a CEP of 2km. Please note that 2000 is a larger number than 20.

Last not least, even though not a SAM, the R 4/M "Orkan" did its job perfectly and was IIRC already developed to a useful stage in 1940.

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It was designed in 1944 not 1940.

My understanding on German SAMS are as follows
Rheintochter
This depended on remote control from the ground a very imprecise method even with todays technology. I have seen live Seacat firings using this method and observed the problems and talked to the operators who had to use it. One simple problem was that the flare tended to blind the target to the operator and that was with a short range missile. It also depended on remote detonation of the warhead. Again very imprecise, the chances of success are limited. The weather would also be a major problem, any cloud would ruin the chances of a hit.
Wasserfall
Basically the control was similar to the Rheintochter, the development you describe was still under development. Its worth noting that the reason it was given a large warhead was because of concerns of the accuracy that could be achieved. Detonation was still remote and simlar sized explosions from air dropped bombs I believe were tried against US bomber streams with limited success.
Enzian
In some ways the more practical option for production but considered by the Germans to be even more difficult to control than the other missiles as it wasn't a line of sight weapon. Interesting to note that the warhead was 500kg but considered to have a lethal range of 45 meters, when the Wasserfall with a 300 kg warhead was supposed to have an effective range of 1000 yards. Something isn't right there.
Feuerlilie25/55
Now with this they could have been in business. The 25 was a research rocket only as it was a supersonic weapon designed to pick up technical data. The 55 was to be the weapon and its development was going very well. But and its a big but, the control of the 25 was a radio control link from an aircraft clearly not applicable in a war situation. I don't know what control method would have been chosen for the F55 but I suspect this would have been the Achilles Heal of the system.
Radar Guided V2
This I hadn't heard of before I have heard of the Leitstrahl-Guide Beam apparatus, but how it worked and what accuracy was achieved I simply don't know. I have seen blanket statements that 20 meters was possible but have seen no evidence to back that up. Normal V2's had an accuracy to London I believe of around 7 miles.

kool kitty89 said:

I'm not sure, but I don't think the HG series was even close to production, and I'n not sure on the considerations to produce it either. (more experimental)

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No they were not. With no enemy jet aircraft in mass production development focused on testing improvements of the basic design rather then developing the next version. I merely used the HG to illustrate that the 262 was far from definitive as the A-1a and that a big potential in performance increase was left both in airframe and engines.

I don't think it's wishful thinking for the Meteor 4 or Vampire to come online before the War's end, ...

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Maiden flight was in May that year, no way the aircraft would've been operational in significant numbers by new years eve. For comparison, check how long it took for the Spit Mk.IVX to go from 'maiden flight' to 'operational' to 'available in significant numbers'.

Glider said:

This I hadn't heard of before I have heard of the Leitstrahl-Guide Beam apparatus, but how it worked and what accuracy was achieved I simply don't know. I have seen blanket statements that 20 meters was possible but have seen no evidence to back that up. Normal V2's had an accuracy to London I believe of around 7 miles.

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Hello Glider,

Radar guided: via "beam-riding" Radio guided: = Leitstrahl-Guide Beam apparatus, is a technique of directing a missile to its target by means of radar

Quote: particularly on batteries where Leitstrahl-Guide Beam apparatus was installed, with V-2s sometimes landing within meters of the target

RIM-2 Terrier missile that were introduced in the 1950's were "beam riders", later variants employed semi-active radar homing to improve their effectiveness

http://www.v2rocket.com/start/deployment/leitstrahl.html

(22)(webmasters note: It is generally believed that the A4/V2 was not an effective weapon because it was not accurate enough to hit an exact target. While pinpoint accuracy was not associated with the V2, it was much more accurate than generally reported. Not every batterie received or installed the Leitstrahl-Guide Beam apparatus, which, was crucial to the greater accuracy of the weapon. In the later stages of the war the accuracy improved greatly, sometimes to within meters of the target.)

http://www.v2rocket.com/start/deployment/mobileoperations.html

Regards
Kruska