Henschel Hs 293 developments and projects

[Jemiba]

The development of the Hs 293 is covered, too, in "Die Geschichte der Henschel-Flugzeugwerke AG 1933 - 45" by Horst Materna.
A series of enlarged versions of the Hs 293A was the Hs 293C, for which different guiding systems were proposed. The C-4
was a pre-version of the later Hs 294 glide torpedo bomb, which was actuallytested. The Hs 293F with a delta wing is shown in a
3-view, unfortunately the description seems to have been fallen victim to the lecturer ... :-\
The Hs 295, although quite clearly recognisable as a derivative of the Hs 293 was an air-to-air missile, carrying a 580 kg war head,
powered by two HWK 109-507D rocket engines, a TV guiding system was planned for the D version. About 50 examples are said to
have been built. The Hs 296 again was an air-to-ground weapon for being released in a dive against amoured sea or land targets with
a 600 kg warhead.

 

[Grzesio]

A series of enlarged versions of the Hs 293A was the Hs 293C, for which different guiding systems were proposed. The C-4
was a pre-version of the later Hs 294 glide torpedo bomb, which was actuallytested.

All Hs 293 C variants were torpedo bombs similar to the Hs 294, just differing with warhead shape and dimensions, guidance systems etc.

The Hs 293F with a delta wing is shown in a
3-view, unfortunately the description seems to have been fallen victim to the lecturer ...

Hs 293 F was designed with enlarged wings to decrease wing loading (it is also said, it was to be simpler and cheaper to build). A number of variants was proposed, before the project was cancelled in the end of 1943.

The Hs 295, although quite clearly recognisable as a derivative of the Hs 293 was an air-to-air missile, carrying a 580 kg war head,
powered by two HWK 109-507D rocket engines (...) The Hs 296 again was an air-to-ground weapon for being released in a dive against amoured sea or land targets with
a 600 kg warhead.

Well, Materna is probably the first author known to me, describing the Hs 295 as an AA weapon. Hs 295 was generally derived from the Hs 293 I variant (which was an air to ground version of the Hs 293 carrying 500 kg HE) and built initially around the Hs 294 airframe with PC-type warhead (1260 kg heavy, 585 kg HE). Later version, the Hs 295 V2, was bigger and heavier, but still based on the Hs 294 components. Hs 296 in turn was a bomb very similar to the Hs 295, just with dive attack capability (as the Hs 293 G). Both heavy armour piercing and shaped charge warheads were proposed here.

According to different authors, Hs 295 is also described as having Hs 293 fuselage and Hs 294 wings, while Hs 296 - Hs 294 fuselage and wings.

 

[Jemiba]

About the AA use of the HS 293 there's a longer quotation from the memoirs of Jürgen Ritter,
who served in the K.G.1 (bomber group) from March 1943 onwards. They started training for launching
Hs 293 from specially modified Do 217 (longer span and and GM-1 device) and guiding them from a height
of about 1000 m above the allied bombers into the bomber formation. It is mentioned, that the idea of the
"Pulkzerstörer" (formation destroyer) was abandoned during autumn 1944, but a special missile for this
purpose could have been plausible, I think.

 

[Grzesio]

Interesting - I'll have to look in the book now - I've never read it thoroughly.
Well, there's no doubt the Hs 293 was considered as an AA weapon too - a dedicated variant was the the Hs 293 H, and some H prototypes were apparently rebuilt from Hs 293 A and tested. There were also some earlier trials of guiding a Hs 293 A into a bomber formation.
But this AA variant had to be modified to some extent, it had to have fifth transmission channel for detonating the warhead (as usable proximity fuzes were lacking) and some kind of a selfdestruction fuze was desirable too.

EDIT

About the AA use of the HS 293/295 there's a longer quotation from the memoirs of Jürgen Ritter

He mentions the Hs 293 only, not the Hs 295.

 

[Jemiba]

Sorry, I've corrected my post, I just wanted to point out, that those tests with the Hs 293 as an AA weapon
seem to make the development of a dedicated AA version plausible.

 

[Grey Havoc]

View: http://www.youtube.com/watch?v=x4afXMtBBl4&t=42m37s

An interest tidbit at the timestamp regarding the emergency 'electric razor' countermeasure used by the Royal Navy against the Hs 293 glider bomb and FX 1400 (Fritz X) glide bomb.

 

[Justo Miranda]

'The biggest target in the world', where any German pilot could easily strike with his bombs, was in 1940 the great city of London. But which one was the tiniest and most difficult? No doubt, it was a small English destroyer desperately maneuvering to avoid the attack of the Stukas. Naval targets were so difficult to hit that on July 12, 1940, during a series of aerial attacks by the Regia Aeronautica bombers, against the big and sluggish British battleship HMS Warspite, not even one of the 300 bombs dropped between 8:50 and 11:50 hit the target.

The Germans created guided missiles which could be launched from planes at a great distance from the Allies fleets, thus these planes were not exposed to the efficient anti-aircraft artillery of the ships. At first, they consisted of already existing weapons that had been tested in combat to which had been added some aerodynamic devices. Adding wings and tailfins to standard bombs and torpedoes made them capable of gliding until their impact against the ships. They were guided to the target by a cable or a radio beam or by means of rudimentary passive sensors of radar.

On September 8, 1943, some Dornier Do 217 K-2 bombers from the II / KG.100 sank the Italian battleship Roma with Fritz-X guided bombs. On September 11, 1943, the light cruiser USS Savannah suffered extensive damage after being hit by another Fritz-X. The light cruiser HMS Uganda was also hit on September 13, 1943 and put out of action for almost the entire war as a result. On September 16, 1943, the HMS Warspite was hit by two Fritz-X, suffering extensive damage, and the cruiser USS Philadelphia was very slightly damaged in the same combat. On January 23, 1944, the HMS Janus was struck by one Fritz-X.

Having in mind the most conservative statistics of the time, 5,000 conventional bombs would have been necessary to achieve the same result. The radio control system used by Fritz-X was susceptible to the electronic countermeasure named Electric Razor. After the initial attacks in 1943, the Allies went to significant effort to develop jamming devices which automatically defeated the bomb receiver, regardless of which radio frequency had been selected. In early 1944, the Allies could already interfere any German radio guidance system and most missiles construction programs had to be cancelled.

 

[Grzesio]

In early 1944, the Allies could already interfere any German radio guidance system and most missiles construction programs had to be cancelled.

Really?

 

[T. A. Gardner]

On the subject of jamming Hs 293 and Fritz X bombs:

Both operated on the same guidance system, the Kehl-Strassbourg radio CLOS system. This used 18 channels between 48 and 50 MHz with square wave modulation. The carrier wave ran at 1 to 12 MHz. The channel(s) for guidance were preset before take off.

Alfred Price in The History of US Electronic Warfare vol. 1 (of 3) discusses this at some length. The US reaction was quite different from the British. And, no, electric razors really wouldn't work. They don't generate enough noise on the specific frequencies and are non-directional so they'd be worthless as a jammer, even if it raised morale.

Anyway, the US immediately after the first attacks using these bombs started putting Hallicrafter S-27 and S-35 (USN designation RBX and RCX) receivers on ships covering the 27 to 220 MHz band to listen for the guidance signal(s). Jamming sets based on the APT-1 to 4 sets used by the USAAF were hand built to cover the suspected guidance frequencies (XCJ, K, L).
These were modified again in the field once the actual frequencies were known.

These jammers were of indeterminant value. It is likely they did successfully jam some bombs. Jamming was made difficult both by the frequency the Germans chose and the ability to use different channels that had to be detected then specifically tuned to for jamming.

At the same time, the Germans started to discover that many of these missiles / bombs had been very cleverly sabotaged to make the guidance system fail by the saboteur(s) cutting the coax cable for the aircraft transmitter antenna lead then reassembling the cable. Vibration in operation would break the cable's wire intermittently meaning loss of transmission. About half of all sets in service were found to have been so sabotaged.

By February 1944 an intact Hs 293 had been captured and the guidance system was now known for certain. The Navy adapted US Army ARQ-8 radio jammers for shipboard use as a countermeasure. These operated at 25 - 100 MHz at 30W broadcast power. The definitive set for jamming the Hs 293 / Fritz X was the Navy MAS jammer. This was a 250 W that covered 41 to 51 MHz with square wave modulation at 1, 1.5, 8 and 12 MHz that mimicked the German control system almost exactly. The operator on this set could almost instantly switch by push button to the exact frequency regardless of what channel was chosen, the German control signal was on after detecting it. So, jamming increasingly became more effective.

Also, given the known history of other such guided weapons like the USN Pelican or Bat, it's likely that the German guidance system was neither so reliable or accurate that a hit could be ensured using it. It's likely many fully guided bombs simply missed their target due to inaccuracies in guidance or a failure of some component during the delivery sequence.

 

[klem]

Another earlier version of Hs 293 D with TV guiding system (versuchsversion fuer fernseh-zielweisung)

 

[Grzesio]

Another earlier version of Hs 293 D with TV guiding system (versuchsversion fuer fernseh-zielweisung)

I doubt, it is a TV guided missile. Hs 293 V6 was generally a low profile variant developed for the Ar 234 - its fuselage was just 815 mm high as compared to 980 mm of a regular Hs 293 A-1. The drawing represents an unpowered prototype from the first batch of 25 ordered in early October 1944; the bomb was lengthened by 200 mm for some reason (probably due to the smaller fin; the lengthening insert is empty, though) and there's apparently an additional weight mounted on its nose plus a mysterious 'something' under the weight, connected with a cable to the fuselage. But I really do not think, it is a TV camera, particularly that there are no antennas on the missile other than the regular Kehl/Strassburg one.

 

[T. A. Gardner]

I agree with Grzesio, it wasn't television guided. Television equipment of this period was bulky. This is the US GB-4 television guided glide bomb:



That large box on the bottom held the television camera and transmitter. I seriously doubt the Germans could have miniaturized a television camera to take up much less space.
Now, what's shown could be an infrared seeker. Those are about the correct size. However, if that is so, it would likely be of little real value as the state of the art in infrared seekers at the time limited them to maybe a few hundred yards effective range at most, and often less.

 

[klem]

Quoted by Wolfgang-D. Schröer in "Lenkkörper und Zielweisungsgeräte der deutschen Luftwaffe-Das »Tonne-Seedorf«-Projekt-Teil II. Seite-217.

 

[Dilandu]

But I really do not think, it is a TV camera, particularly that there are no antennas on the missile other than the regular Kehl/Strassburg one.

In pure theory, it may be a persicope connected to internally-mounted TV camera - but I don't think so, frankly.

 

[Kat Tsun]

The 293D was TV guided but the picture appears to be missing some things, notably the large uplink antenna on the tail and the television camera that would be contained inside a nose fairing.



For an idea of the size of the fairing:



Any other TV installation would be similar in size and likely hollow.

e: Yeah Grzesio got it.

It's probably a terminal infrared seeker or something if that's a cable going back to the control surfaces and not a guiding line or something for the drawing. Perhaps a level drop and some final autonomous guidance to overcome Allied jamming on warships was intended. The other possibility is it is a flare for the test range crew to better follow the bomb's trajectory from the ground, given it is meant to be test dropped from the Arado bomber and not a series production item, I imagine it would be something related to drop tests than combat use.

 

[klem]

In Schroer's book quoted above (#13) and by summary on pages 7-8-9, he explains that for installation the television-assisted guidance system in the Hs 293 , the guidance body had to be extended at two points. On the one hand, sufficient space had to be created at the front of the cell to accommodate the electronic camera. This was done by attaching a cap adapted to the profile of the bomb and, on the front side, a viewing window for the view of the camera was screwed . Since there was not enough space in the equipment compartment of the Hs 293 Standard, an intermediate ring had to be placed in the rear part of the guide body, in which the TV transmitter and his feed could find space. Figure 6b shows the installation position of the TV transmitter and its power supply on the front panel. The 5-element Yagi antenna attached to the rear, horizontally then vertically, grouped at the rear relayed the television signal. To make things easier, a sighting device was fixed directly in front of the lens - temporarily - whose image was visible on the television picture. The image sensor tube was shown (image 5b). Subsequently the lens n was not rigidly installed at the front, it could now be moved in the direction of the vertical axis of the steering body. The setting was regulated by a vane, so the line of sight of the camera was always "aerial" in the direction of flight.

 

[Ivan Culjak]

Hi,
There are so many posts on Hs-293, so it could be some repetition, so sorry in advance,
First is about a very authoritative You tube channel Deutsche Avionik from Dieter Beikirch's collection. One of the videos is about Henschel Hs 293 radio control system with information on wire guided version (from 11:29).
Second info on Hs-293 is about the very first use of a digital process computer in production.
Namely, one of the pioneers of digital computers, Konrad Zuse and his company, built computers for Henschel. From wikipedia (https://en.wikipedia.org/wiki/Konrad_Zuse) - “Zuse built the S1 and S2 computing machines, which were special purpose devices which computed aerodynamic corrections to the wings of radio-controlled flying bombs. The S2 featured an integrated analog-to-digital converter under program control, making it the first process-controlled computer”.[23]: 75 

“Radio-controlled flying bombs” mentioned there were Hs-293s. Prof. Wagner realized that due to small physical dimensions, even small manufacturing imperfections affected missile properties quite badly, especially its aerodynamics properties. So, every missile (wings and control surfaces) needed to be calibrated. This process was quite cumbersome and lengthy. Zuse came up with a solution to do it automatically, doing more than 100 measurements at the same time and calculating necessary corrections, instantly. After that, trimming of wings and rudders was an easy task.
Here is an excerpt from Konrad Zuse biography - Konrad Zuse (auth.)-Der Computer — Mein Lebenswerk-Springer Berlin Heidelberg (1986), p.64

And, from p.65, a patent for the first AD (analog-digital) converter (“abtastung" is scanning):

 

[klem]

View: https://www.youtube.com/watch?v=fXRP_H78oso

 

[HoHun]

Hi Ivan,

Here is an excerpt from Konrad Zuse biography - Konrad Zuse (auth.)-Der Computer — Mein Lebenswerk-Springer Berlin Heidelberg (1986), p.64

And, from p.65, a patent for the first AD (analog-digital) converter (“abtastung" is scanning):

Fascinating stuff, thanks a lot!

Considering that there were (according to the German caption) 100 measuring indicators running over the wing surfaces, I felt reminded of this purely mechanic 2D integrating machine:

View: https://www.youtube.com/watch?v=u3vHZqsY9Qg&t=8s


By "scanning" hides along a limited number of lines, and using ratches for "storing" the scanned dimensioned, it happened to be a digital machine, though the final addition of the individual "digital" values was accomplished by use of a whipple tree mechanism, which probably counts as analog calculation.

Of course, Zuse's invention takes his machine *literally* into another dimension :-D

Regards,

Henning (HoHun)

 

[Dilandu]

Radio-controlled flying bombs” mentioned there were Hs-293s. Prof. Wagner realized that due to small physical dimensions, even small manufacturing imperfections affected missile properties quite badly, especially its aerodynamics properties. So, every missile (wings and control surfaces) needed to be calibrated.

Typical German engineering at its worst; instead of improving the autopilot and controls, they invent a massive computing machine to polish hulls perfectly.

 

[Dilandu]

P.S. I recall a story from XIX century American journalist, who visited some industrial exgibition in Germany. He observed a massive industrial machine, that was switchsd on and off by lever handle (only on and off, no middle positions!), and a small intricated geat changed the signs "on" and "off" (in German) in a xast-iron cupola on the top of machine. The American asked, why can't they just took a paint and a brush and wrote "on" and "off" near the level. The German inventor looked at him almost with disgust for suggesting such simple and un-complicated solution...

 

[Nicknick]

Typical German engineering at its worst; instead of improving the autopilot and controls, they invent a massive computing machine to polish hulls perfectly.

Simply, because you have to bulit this advanced computer only one time, but the improved (and certainly more comlex) autpilot a thousand times.

As well as we allready learned from the PWM control system, we also learned that German guided bombs were pioneering the digital computing.

 

[Dilandu]

Simply, because you have to bulit this advanced computer only one time, but the improved (and certainly more comlex) autpilot a thousand times.

The improved autopilot may be put to better use than primitive MCLOS control link (that Germans didn't even managed to replace with anything as soon as jammers made it inefficient). And it would allow more flexibility for the missile itself.

 

[Nicknick]

Instead, they developed one of the first (if not the first) programable computer and found a quick solution which required no further investment in single use components.

As we learned above, jamming wasn't easy and it took a while until the Americans found a way. The signal transfer via PWM is more stable than an analog system.