# Hs-129: asset or liability; alternatives?



## tomo pauk (Oct 29, 2014)

A spin off from another thread. How much the Hs-129 was important to the German war effort? How well/bad is fares against other assault aircraft? Was it the best the Germans were capable for in 1941-44 time frame? Was the lack of rear gunner a shortcoming?


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## GrauGeist (Oct 29, 2014)

The Hs129 was a very effective weapon against ground targets. The Gnome-Rhône 14M engines may have been a little bit underpowered for the platform, but it proved it's worth many times over, like at the battle of Kursk, for example.


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## at6 (Oct 29, 2014)

Given proper German engines, it would have probably decimated Russian tank columns even more so than the JU-87G which in the right hands was formidable.


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## wiking85 (Oct 29, 2014)

Liability overall IMHO, but so low resource costing that there are good points to having it. Basically it was really only useful by 1943 to stop breakthroughs of Soviet armor or even offensively against Soviet armor reserves massing at places like Kursk provided there is enough air support. It doesn't replace the Ju87G, but neither aircraft were really ideal; the best option given the technology of the time would have been Fw190Fs with R4M/Panzerblitz rockets but that didn't develop until 1945. Had it been an option, which technologically it would have been possible by 1943 had the concept been arrived at, it would have been as good or better than the Ju87G/Hs129 combo.
Ideally to me there would have been no end of Hs123 production and in fact a 123C with fully enclosed, armored cockpit and have it use the Panzerblitz rocket when it became available. Having several hundred Hs123Cs instead of all the Hs129s would have been more effective IMHO, as they were cheaper, lighter, easier to fly, and more useful in the East. Having 300 operational at any one time would be a good start, though more are better, especially as they can be used at night as a harassment bomber (alongside the Ju87R).

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## Siddley (Oct 29, 2014)

The Argus engined A series weren't very popular with pilots, to say the least ( Cpt Eric 'Winkle' Brown said that when he asked a HS-129 pilot about the A series the guy shuddered and called it " a monster " ) ...but the B series was very much better.

One of my personal ways to judge an aircraft is by it's service life, and the HS-129 B series had plenty of that, and plenty of tank kills.

With a couple of 801's it could have been something quite special. Maybe, anyway


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## Shortround6 (Oct 29, 2014)

Just so we are all on the same page (or at least the same chapter) the HS 123 stopped production in late 1938. There were only 10 of the Argus powered H2 129s ever built and they never saw combat, two of them went back to the factory to become prototypes for the Gnome-Rhone powered B series. Bomb loads I gave earlier were for the early B series aircraft. Later B series aircraft lost the 7.9mm MG 17s to provide more weight and space for ammo for the 30mm/37mm gun. 

There was *NO* "proper" German engine that the airframe could use. The Gnome-Rhone was a 18.9 liter 14 cylinder engine of only 950mm diameter that weighed around 420kg. The German 9 cylinder radials were much larger in diameter and much heavier. Sticking BMW 1000kg BMW 801s on the small airframe just wasn't going to happen.


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## gjs238 (Oct 29, 2014)

Scavenge R-1820's and R-1830's?


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## Shortround6 (Oct 29, 2014)

Still hundreds of pounds heavier and in the case of the R-1820 really bigger in diameter. Early R-1820 537kg, 30 liters, 1378mm in diameter. Will also need bigger propeller. R-1830 is _only_ 1220mm in diameter but even heavier than the R-1820s. The German 9 cylinders radials were fairly close to the R-1820 in diameter and weight.


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## Siddley (Oct 30, 2014)

They were investigating a scheme to re-engine the HS-129 with BMW 801's but I can't give you anything more definitive than that because I read it in a book on the 129 which I no longer have.


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## Shortround6 (Oct 30, 2014)

OK











They can investigate all they want. it comes down to how practical it was. The Me 209 II was _supposed_ to use a large amount of Bf 109 parts, tooling, etc and be an _easy_ way to get a higher performance fighter. Not only was performance lower than expected but common parts/assemblies had fallen to 30%. 

Doubling the weight of the powerplants that are that far forward is going to need _some_ revision to the rest of the airframe. Lets not forget that the Gnome-Rhone engines used in the B series Hs 129 were already about 100kg heavier than the Argus 410 engines the plane was original designed for and that is dry weight. The Argus 410s used 2 bladed propellers. 

You could certainly build a close support plane using a pair of BMW 801s, you could base it off of the HS 129 and call it the Hs 129C or D or the Hs 229 or what ever. The Germans (and others) certainly did that with a number of other aircraft ( Do 17 and 217 share next to no parts) or look at the changes from a B-17D to a B-17E (almost a new plane from the radio compartment aft). 

A Hs 129 only weighed 4000kg empty, adding 1000kg worth of engines is going to call for some major revisions.

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## tomo pauk (Oct 30, 2014)

The Merlin Whrilwind was probably a far more a realistic thing than Hs-129 with BMW 801 engines.


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## GrauGeist (Oct 30, 2014)

There were two proposed types: 
The Hs129C was intended to use an Italian based V-12 engine, but it never happened.

The Hs129D was projected to have either the Jumo211 or BMW801 but this was nothing more than a proposal.


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## Shortround6 (Oct 30, 2014)

At least the Hs 129C was only trying to jump the weight of the engines by about 100kgs each and not around 500kg each like going to the BMW 801s. 
Of course it wasn't going to get a big boost in power either.


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## stona (Oct 30, 2014)

tomo pauk said:


> The Merlin Whrilwind was probably a far more a realistic thing than Hs-129 with BMW 801 engines.



And that was only ever a long shot. A Merlin XX powered Whirlwind was actually proposed by Sir Eric Mensforth directly to Fighter Command (unwisely short circuiting the usual channels through the Air Ministry) in a letter to Sholto-Douglas of 21st January 1941.

There were many problems. Not least the Merlin used an up draught carburettor which would occupy much of the space at the lower rear of the engine installation normally occupied by Whirlwind's main undercarriage mounting. No one seems to have had a solution to this and unlike people writing on modern forums nobody suggested that Rolls Royce make any changes to the engine's layout to accommodate the airframe. 
The nacelles were also too close to the fuselage to allow a larger propeller which would be needed for the more powerful Merlin, though Petter proposed a smaller four bladed propeller. It never amounted to more than a proposal.

It was all a moot point as Tizard, the chairman of the Joint Development and Production Committee, noted in February 1941 that the Whirlwind used two engines that had no other use and consumed 50% more material than a Spitfire to do the same job less efficiently. In fact a Whirlwind consumed nearly three times as much alloy as a Spitfire! This was why Tizard endorsed the cancellation of the project (on 3rd February) and only 114 Whirlwinds were ever produced. 

Again, compare this ruthless drive to get the most out of the British aircraft industry, taking the hard decisions, with the endless prevaricating, cancellation and then countermanding orders, typical of the RLM's management of its programs.

Cheers

Steve


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## Shortround6 (Oct 30, 2014)

Yeah but they _should_ have compared the Whirlwind to the Typhoon instead of the Spitfire 

Empty weight: 8,310 lb vs Empty weight: 8,840 lb and two 12 cylinder engines that had no other use vs one 24 cylinder engine that had no other use (although they wanted to) 

Hindsight is a wonderful thing

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## GrauGeist (Oct 30, 2014)

The fact that the Hs129 was a purpose-built ground attack aircraft does show that the Luftwaffe was looking in the right direction for a dedicated Ground Support platform.

Unlike the Hs123, which was adapted for the role, or other aircraft that followed suit, the Hs129 was designed from the start for close support with it's heavy armor and air-cooled engines. However, it was under-powered and much like the Ju87, needed the protection by means of air supremacy in order to operate un-molested.

What it did accomplish on the battlefield (even in the small numbers that were built), however, was proof that it was a sound concept.

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## stona (Oct 30, 2014)

Shortround6 said:


> Yeah but they _should_ have compared the Whirlwind to the Typhoon instead of the Spitfire
> 
> Empty weight: 8,310 lb vs Empty weight: 8,840 lb and two 12 cylinder engines that had no other use vs one 24 cylinder engine that had no other use (although they wanted to)
> 
> Hindsight is a wonderful thing



Earlier Dowding did, although the 'Hawker fighter' he referred to was not yet the Typhoon. He noted that the Whirlwind used two engines to lift the same four 20mm cannons as the 'Hawker fighter' would. At the time (July 1940) he was prepared to give a limited reprieve as the only viable cannon armed fighter available. He did however conclude that _'we shall be glad enough to drop them when the Hawker fighter comes into heavy production'. _

Neither Dowding, nor Tizard had the benefit of hindsight. They both concluded that a twin engine cannon armed fighter was not the most efficient use of available materials and production capacity. The Whirlwind only ever had a limited reprieve (the 114 finally ordered) after Newall's axe initially fell because Aberconway and Mensforth successfully argued that not only the jigs but parts _already produced_ for about one hundred aircraft would be wasted. The Supply Committee also established independently that a 'substantial number' of part finished Peregrine castings and forgings were available. In the end only around 300 Pregrines were built (I can't find the exact number) a paltry amount in the scheme of WW2 aero engine production.

114 aircraft and around 300 engines makes the Whirlwind/Peregrine combination little more than a foot note in aviation history. It was a program that was rightly terminated when it was. It wasn't allowed to drag on for years and it wasn't allowed to compromise production of other types by Westland and that included the Lysander which was specifically mentioned in this context by Freeman.

Cheers

Steve


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## gjs238 (Oct 30, 2014)

stona said:


> It was all a moot point as Tizard, the chairman of the Joint Development and Production Committee, noted in February 1941 that the Whirlwind used two engines that had no other use and consumed 50% more material than a Spitfire to do the same job less efficiently. In fact a Whirlwind consumed nearly three times as much alloy as a Spitfire! This was why Tizard endorsed the cancellation of the project (on 3rd February) and only 114 Whirlwinds were ever produced.



Wonder what Tizard thought (or would of thought) of the P-38...


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## tomo pauk (Oct 30, 2014)

GrauGeist said:


> The fact that the Hs129 was a purpose-built ground attack aircraft does show that the Luftwaffe was looking in the right direction for a dedicated Ground Support platform.
> 
> Unlike the Hs123, which was adapted for the role, or other aircraft that followed suit, the Hs129 was designed from the start for close support with it's heavy armor and air-cooled engines. However, it was under-powered and much like the Ju87, needed the protection by means of air supremacy in order to operate un-molested.
> 
> *What it did accomplish on the battlefield *(even in the small numbers that were built), however, was proof that it was a sound concept.



Dave - what the Hs 129 accomplished on the battlefield?


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## davebender (Oct 30, 2014)

Ju-87D/G can do everything Hs.129 can do only better and for lower cost.


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## stona (Oct 30, 2014)

gjs238 said:


> Wonder what Tizard thought (or would of thought) of the P-38...



Probably not a lot, but the British in 1940/41 were trying to produce aircraft under very different circumstances to the Americans. It was an awareness of those circumstances and limitations which informed decisions like those taken by Tizard's committee, and they didn't apply across the Atlantic.
They did apply in Germany, though the RLM didn't act as if they did.
Cheers
Steve

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## GrauGeist (Oct 30, 2014)

tomo pauk said:


> Dave - what the Hs 129 accomplished on the battlefield?


I am looking for a great book I have, about the Hs129 and it's history. For such a low production total, they accounted for a great deal of AFVs in their theaters of operation. There were a number of pilots who were exception with the Hs129, one in particular, was Hauptmann Heinz-Rudolf Ruffer of 8./SG 1 flying red "S" (WkNmr. 0364) and red "G" (WkNmr. 141966).



davebender said:


> Ju-87D/G can do everything Hs.129 can do only better and for lower cost.


Not true, the Hs129 was cheaper to manufacture than the Ju87 and required only one crew member. And the Hs129 had a higher survivability than the Ju87 because of it's heavy armor...

Also, the Ju87G, armed with the Bk3,7 only had a total of 12 roundswhich meant it had a limited amount of opportunities against targets while the Hs129 had a higher capacity, allowing it more opportunities. It is true that the number of Hs129 types equipped with the Bk3,7 were limited, but they proved their worth. So to, did the limited Hs129s equipped with the Bk7,5.

While the Hs129 equipped with the 30mm may not have been a T-34 destroying beast, it did account for plenty of other AFV types. The technique that the Hs129 employed, was to get within 100m of their target and open up from a "diving" angle, which allowed penetration of the thinner armor found across the top and rear of their target and proved very successful.

They were known to fly just above the treetops and in some cases, nearly on the ground...this is why they sported the Infantry badge on the cowling and were nicknamed the "flying infantryman".

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## Shortround6 (Oct 30, 2014)

stona said:


> . It was a program that was rightly terminated when it was. It wasn't allowed to drag on for years and it wasn't allowed to compromise production of other types by Westland and that included the Lysander which was specifically mentioned in this context by Freeman.



I was to some extent joking but I am a bit baffled that the aircraft were looked at in such a simplistic way, Or to put it another way two engines with 24 cylinders total in the Whirlwind are so much more expensive than one engine with 24 cylinders total in the Hawker Tornado _using the exact same piston, rings, valves, valvesprings, camshafts_ in the R-R Vulture. Yes you need two prop hubs and more engine controls/instruments. 
The actual utility of the Lysander in modern air combat also needed a major rethink. Way too big and expensive for artillery spotting and battlefield observation and 'liaison' and yet nowhere near high performance enough to act as a daylight tactical strike aircraft. Whatever it's deeds at agent dropping/recovery and supply of underground fighters (both not in it's original spec) it was major flop at most it's intended jobs. It's crews were brave and suffered as much as the Battles and Blenheims in France, they just didn't attack any 'high profile' targets to attract attention as they were shot down in horrifyingly large numbers.


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## stona (Oct 30, 2014)

But they were 

To be fair Dowding was no fan of Westland or the Whirlwind, but he did anticipate the need for a cannon armed fighter both as bombers became more heavily armoured and, in 1940 when he wrote that, to deal with the prospect of German tanks on English beaches.

Tizard and his committee were probably looking at statistics rather than performance charts. I believe that they were simply looking for the biggest bang per ton of aluminium etc. They were not happy about the Blenheim but conceded due to its ability to carry out several roles. As it happens I think they would have come to the same conclusions about the Whirlwind had they looked at those performance charts. It really wasn't a great aeroplane. Westland didn't help their case by taking a long time to develop it, producing early production aircraft with some serious short comings and failures as well as claiming performance for it that it never achieved. 

Freeman was writing in 1940 and was keen that Army Co-operation Command should receive its Lysanders.

Cheers

Steve


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## davebender (Oct 30, 2014)

We know what Ju-87 (including engine) cost in late 1940 / early 1941. Do you have a historical production cost for Hs.129 including both engines?


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## Shortround6 (Oct 30, 2014)

stona said:


> Freeman was writing in 1940 and was keen that Army Co-operation Command should receive its Lysanders.



when in 1940?

After the battle of France nobody should have any illusions that Lysanders had any business at all in contested airspace. " Air Marshal Arthur Barratt, commander-in-chief of the British Air Forces in France as "quite unsuited to the task; a faster, less vulnerable aircraft was required.", They did a bit coastal patrol work after the fall of France (mainly because the squadrons had little else to fly... Bothas?) and the Canadians used them for a bit of patrol work but Lysanders rarely flew combat mission again aside from places like Madagascar and in support of the Chindits. For 1786 planes being built their combat effect was rather limited.


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## stona (Oct 30, 2014)

Shortround6 said:


> when in 1940?



My bad. September 1939, in a letter to Sir Charles Bruce-Gardner, Chairman of the Society of British Aircraft Constructors.

_"It is strongly recommended, and I have no doubt will be approved, that the Whirlwind should be stopped forthwith, thus enabling us to replace it at Westlands with the Lysander, which is required in large quantities to meet the needs of an Expeditionary Force and of our Dominion forces."_

Newall agreed and in October the initial axe fell on the Whirlwind and Peregrine production programmes. The partial reprieve came later as discussed above.

Lord Abercromby, Westland's chairman wrote to Kingsley Wood challenging the decision to cancel the Whirlwind in October and was told in reply.

_"The decisions that have been reached as regards individual firms have been determined in the light of the programme as a whole. As you will realise the large increase in the size of the Army has meant a corresponding increase in the requirements of Army Co-operation aircraft and, while we have several fighter types in production or nearing the production stage, the only really satisfactory Army Co-operation type is the Lysander designed by the Westland Company. We are, therefore, anxious for Westlands to concentrate their undivided attention on the production of this aircraft..."_

That's a polite way of telling Westland to do what they were told.

Cheers

Steve


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## tomo pauk (Nov 1, 2014)

BTW, any takers to change the listed weight on the Wikipedia page about the MK 101? Empty gun weighted 139 kg, 185 kg was the weight for a gun with full 30-round drum. From page 8 of it's manual:


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## gjs238 (Nov 1, 2014)

Done
https://en.wikipedia.org/wiki/MK_101_cannon

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## tomo pauk (Nov 1, 2014)

Good. 
The manual is the 'MK 101 Waffen Handbuch', can be downloaded from here: http://www.deutscheluftwaffe.de/archiv/Dokumente/ABC/m/MK%20101/Text/Handbuch/MK%20101%20Waffen%20Handbuch.pdf


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## Denniss (Nov 1, 2014)

And I changed some other incorrect data.

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## tomo pauk (Nov 6, 2014)

So what would be the alternatives to the Hs-129? Armour-up the Ju-87, install the 2 x MG-FF canons, later two MK-101. Retaining the dive brakes could enable attacks from 60-75 degrees with the 30mm to punch through the top armor of many tanks. Granted, the 1000 kg bomb is out of the question, since most of the weight allowance will be consumed by the armor, so we would probably see a 250 kg + 2x50 kg and 2XMG-FF, for the Ju-87-based attacker. Advantage vs. Hs-129A - it can actually perform.
A Ju-87D-based attacker: the armor is already upped by almost 300 kg, but we will add a bit more armor and forget the 1800 kg bomb, settling with 250 kg + 2x70 + 2xMK-101 (= 750 kg with full 30mm ammo). Advantage vs. Hs-129B - much bigger punch, rear gunner, need less fuel per ordnance carried, can be available some 10 months earlier, much more reliable engines. Disadvantage - only one engine.

What to do with those French engines that we have captured? Re-engine the Ju-87 with G&R 14N. The Fw-189 can have the 14M.


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## Shortround6 (Nov 6, 2014)

tomo pauk said:


> So what would be the alternatives to the Hs-129? Armour-up the Ju-87, install the 2 x MG-FF canons, later two MK-101. Retaining the dive brakes could enable attacks from 60-75 degrees with the 30mm to punch through the top armor of many tanks. Granted, the 1000 kg bomb is out of the question, since most of the weight allowance will be consumed by the armor, so we would probably see a 250 kg + 2x50 kg and 2XMG-FF, for the Ju-87-based attacker. Advantage vs. Hs-129A - it can actually perform.
> A Ju-87D-based attacker: the armor is already upped by almost 300 kg, but we will add a bit more armor and forget the 1800 kg bomb, settling with 250 kg + 2x70 + 2xMK-101 (= 750 kg with full 30mm ammo). Advantage vs. Hs-129B - much bigger punch, rear gunner, need less fuel per ordnance carried, can be available some 10 months earlier, much more reliable engines. Disadvantage - only one engine.
> 
> What to do with those French engines that we have captured? Re-engine the Ju-87 with G&R 14N. The Fw-189 can have the 14M.



Will you please forget about the near vertical dive for anti-tank work. At what altitude do you need to start the pullout? 600 meters? 800 meters? 1000 meters? Accuracy is going down hill fast and people started giving up on the dive bomber attack profile as the light AA got better. It is one thing to trade 3-6 dive bombers for a ship. It is another to trade a dive bomber for even two tanks. The dive bomber attack profile also sets you up for the defending fighters. Instead of approaching the target area at few hundred ft (at most) and trying to blend in with the terrian the dive bomber has to approach at several thousand meters (3-4000) actually _identify_ the target tanks at that altitude and then start the dive. Everybody for miles around can see you if you can see them. (low clouds?) *OR* come in low, spot targets and then spend several minutes climbing to attack altitude? 

Not sure what the G-R 14N in a JU-87 gives you? Less power and more drag? Not that the JU-87 engine installation was anything to brag about. 






You may not be able to use those tight fighter cowlings at the speed the Ju-87 is going to fly and cutting your take-off power by about 10% isn't going to do much either.


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## tomo pauk (Nov 6, 2014)

Vs. the Jumo 211B (as used on the Ju-87B), the later G&R 14N will have 20-80 HP less for take off, not 20% less. The drag of the radial will be of the least worry, at least until we ditch, say, the spatted U/C and thick big wing, and that is not going to happen.


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## GrauGeist (Nov 6, 2014)

The Hs129 alreadt proved it's effectiveness by flying low (very low) over it's target area (hense the name "Flying Infantryman") and it packed a good punch with the 37mm. The downside of the Ju87G armed with the 37mm was that it could only carry 6 rounds per cannon. Granted the 37mm equipped Hs129 only carried a single (with 12 rounds) but it did not have a convergance issue, the cannon was along it's centerline, improving accuracy. 

The Hs129 also attacked it's targets from above at a sloping angle as well as from behind, typically from a low altitude, unlike the Stuka, which typically entered it's attack at a considerably higher altitude.

The Hs129's mode of attack gave it an element of surprise, as it wasn't usually seen (or recognized) until it was right on top of it's target.

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## Denniss (Nov 7, 2014)

The Ju 87G carried 12 rounds per 37mm gun, two 6-round clips slapped together. 6 rpg is an old myth.


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## tomo pauk (Nov 7, 2014)

As is the 'tail gunner, somehow, reloads the cannons'?

BTW, here is a graph that shows the LW diving attack starts from 5000 ft (~1700 m), with a pull out initiated from 1500 ft (~500 m):

Junkers Ju 87 â€“ Wikipedia


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## Shortround6 (Nov 7, 2014)

Which basically means 500yds (457meters) is as close as you are going to get, or position of your _last_ possible shot at the tank. Plane moves about 40yds between shots if diving at 350mph. 

Video of the Hawker Hurricane with 40mm guns, a bit propagandist and staged but still? They may _start_ firing at more than 500yds or so but last shots are much closer. 


_View: https://www.youtube.com/watch?v=hfziVcyPXII_

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## tomo pauk (Nov 7, 2014)

Thanks for the video

Hopefully no-one will dive the Ju-87 to 350 mph


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## Greyman (Nov 8, 2014)

For what it's worth - Hurricane IId tactics of 6 Squadron in Africa:

"...

The formation goes out at a height of 4,000 feet, which is considered to be above the effective range of small arms fire, and below the level of Breda bursts. Speed is maintained at 180 mph, until the target area is approached, where it is increased to 200 mph. On approaching the target, height is lost to 1,500 feet since at this height observation of ground objects is considerably more accurate. At the same time each Vic changes into line astern.

On sighting the target, the formation goes down to a height of 15/20 feet and approximately 1,000 yards away. On the leader turning to the target, the formation turns inside him and goes into attach in a rough echelon, each member of the formation selecting his own target. The approach is made at 240 mph since the datum line is more than 2 degrees down, the sights being set parallel. Variations of more than 10 mph will affect the accuracy of the shooting. Fire is opened at roughly 700 yards closing to 200 yards, and both Brownings and 'S' Guns are harmonised at 500 yards. After each burst of one shell per gun the sights are realigned on the target. Normally about five bursts can be got in on each attack. The breakaway is made before reaching the target if possible, to avoid being hit by splinters and the area is cleared by low flying and weaving."

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## dedalos (May 14, 2015)

Looking for an imroved Hs 129, with reasonable modifications but requiring some better co operation between germany and japan, what about using Nakajima sakae 21. The zero s engine.Reasonably heavier than the original engines (170kgr), reasonably wider (1150mm vs 950 mm diameter), and 430 hp more powerful.
Plus the potential to use ADI. on Paper it appears perfect
Generally japan had some pretty good radials. Especially the Homare beats BMW801D on every sector,despite using inferior fuel!


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## tomo pauk (May 14, 2015)

The Fiat A.74 might be a closer alternative, in geography, weight and time. ~150 kg heavier than the G&R 14M, 840-960 CV power; a bit wider, though. Italians can come out with a S/C gearing of lower ratio, should provide even more power on low altitudes. 
But then, unless the Hs 129 is not outfitted with at least a 5cm cannon, it would be an expensive alternative to the Ju 87G, both to purchase and operate.


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## Shortround6 (May 14, 2015)

Best alternative are the Italian Isotta-Fraschini air cooled Inverted V-12 engines. At least they are in the same hemi-sphere and don't require shipment by submarine. Weight is closer even if power isn't much different.


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## kool kitty89 (May 15, 2015)

tomo pauk said:


> The Fiat A.74 might be a closer alternative, in geography, weight and time. ~150 kg heavier than the G&R 14M, 840-960 CV power; a bit wider, though. Italians can come out with a S/C gearing of lower ratio, should provide even more power on low altitudes.
> But then, unless the Hs 129 is not outfitted with at least a 5cm cannon, it would be an expensive alternative to the Ju 87G, both to purchase and operate.


If you wanted better performance, load carrying potential, and better survivability (including practical single engine performance), going a step further to the Gnome Rhone 14N might make more sense. 9 cylinder BMW or Bramo radials might be considered as well, but they're a bit larger diameter and lower power (without C3 or WM/50 ... or the late BMW 132 models that don't seem to have seen service).

The Isotta Fraschini Delta wouldn't address the power loading issues much (depending on the model), but might reduce drag somewhat. It probably would have been more interesting if used directly as a follow on to the Argus engines in the prototypes in place of the 14M.

For that matter, the Delta is one engine that got overlooked in the recent Fw 187 discussions.


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## GrauGeist (May 16, 2015)

kool kitty89 said:


> ...or the late BMW 132 models that don't seem to have seen service)...


The later, more powerful BMW132 was used in at least two types that I am aware of, the Ar196 (BMW132Dc) until 1944 and the Ju52/3Mg7 (BMW132T) until 1945.

The BMW132 (especially the D series) would have been an ideal engine for the Hs129, the B-2 was already set up for radials (700hp) and installing the 132Dc (838hp) or the 132De (868hp) woild have certainly seen an improvement in performance.


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## Shortround6 (May 16, 2015)

Ok Guys, the Gnome Rhone 14M engine was a _tiny_ engine, not just in power but in size and weight. It was sort of a 3/4 scale 14N. 

It was only 950mm in diameter. One of the proposed engines (the BMW 132) is 430mm (16.9in) bigger in diameter. See the 3 view drawing in post #10. Unless you change the thrust line you are going to be dealing with cowls a good 200mm (8in) higher making vision to the sides a bit of a problem. The extra drag is going to kill some of the performance. The extra power is going to handy for lifting a bigger load but the BMW radials have *twice* the frontal area of the 14m. That makes them bigger targets too. 

The Hs 129 wasn't a really big plane, it was big compared to a 109 but.







and this is what it started as






you really want to stick a _pair_ of these on it.

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## Gixxerman (May 16, 2015)

I recall reading once that the LW never had more than about 500 Ju87's available at any one time.
Therein (even if only approximately true) lies a lot of the (increasing) problem Germany had, too few against way too many.
Regardless of individual airframe/weapon performance etc.


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## dedalos (May 16, 2015)

Shortround6 said:


> Ok Guys, the Gnome Rhone 14M engine was a _tiny_ engine, not just in power but in size and weight. It was sort of a 3/4 scale 14N.
> 
> It was only 950mm in diameter. One of the proposed engines (the BMW 132) is 430mm (16.9in) bigger in diameter. See the 3 view drawing in post #10. Unless you change the thrust line you are going to be dealing with cowls a good 200mm (8in) higher making vision to the sides a bit of a problem. The extra drag is going to kill some of the performance. The extra power is going to handy for lifting a bigger load but the BMW radials have *twice* the frontal area of the 14m. That makes them bigger targets too.
> 
> ...



That a why Sakae would be Ideal for the aircraft. The various altrernative italian engines simply are too weak to make any Real difference
I dont find impossible that germany could get licence to produce the sakae 21. It would be useful for other aircafts too.(ar 196,do 24 etc)


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## tomo pauk (May 16, 2015)

In case Germany gets way too much of the G&R 14N engines, stick them on the Ju 87. Using 28 cylinders to have one 30-37mm cannon airborne is rather wasteful. Let alone all the fuel it would've burned to kill a tank or two, maybe. As SR6 noted above, the Hs 129 started with 315 kg light Argus 410 engines.



dedalos said:


> That a why Sakae would be Ideal for the aircraft. The various altrernative italian engines simply are too weak to make any Real difference
> I dont find impossible that germany could get licence to produce the sakae 21. It would be useful for other aircafts too.(ar 196,do 24 etc)



Going with G&R 14M meant that bare engine weight is up by 2 x 100 kg. The wing sweep was 'deleted' in order for CoG to remain in limits. Going with Sakae 21, the bare engine weight goes up by another 2 x 175 kg. Power is there, but what do we gain at the sharp end (= firepower)? The Sakae 21 became available in mid 1942 (?), power was lower with Sakae 11.
The I-F Delta was good for 840 PS, but was 2 meters long - it would be a long shot to install it with CoG remaining in limits. My proposal, the A.74, was much shorter, but again it weights as much as Sakae 21 - 590 kg - too much; max power 960 PS. 

I'd rather propose the LW equivalent of the Yak-9T for the LW, maybe based on the Fw-190.


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## davparlr (May 16, 2015)

Shortround6 said:


> The Hs 129 wasn't a really big plane, it was big compared to a 109 but.



Great Pix. I always thought that plane was way too small to put all the things others have said it could possibly do.


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## kool kitty89 (May 16, 2015)

Shortround6 said:


> It was only 950mm in diameter. One of the proposed engines (the BMW 132) is 430mm (16.9in) bigger in diameter. See the 3 view drawing in post #10. Unless you change the thrust line you are going to be dealing with cowls a good 200mm (8in) higher making vision to the sides a bit of a problem. The extra drag is going to kill some of the performance. The extra power is going to handy for lifting a bigger load but the BMW radials have *twice* the frontal area of the 14m. That makes them bigger targets too.


Yep, all advantages for the Delta over the 14M as well, save weight. Visibility to the sides should have been closer to the original As 410 configuration, granted the 129's cockpit didn't have the best field of view in general, but still a useful improvement. Plus power was a bit better than the 14M, perhaps a bit better still if the supercharger ratio was changed for the low altitudes the Hs 129 really needed.



> The Hs 129 wasn't a really big plane, it was big compared to a 109 but.


Yes, it's very similar in overall size to the Fw 187.




tomo pauk said:


> The I-F Delta was good for 840 PS, but was 2 meters long - it would be a long shot to install it with CoG remaining in limits. My proposal, the A.74, was much shorter, but again it weights as much as Sakae 21 - 590 kg - too much; max power 960 PS.


CoG shift would be a problem for the majority of engine changes in question, but yes that's still a useful point. Using a lower altitude supercharger configuration should have helped with maximum power output as well.



> I'd rather propose the LW equivalent of the Yak-9T for the LW, maybe based on the Fw-190.


You'd have to make it DB-603 powered to manage a nose mounted cannon or resort to Hurricane IID style underwing pots. (but a BK37 is a good deal larger and heavier than the Vickers S and the Fw 190 has a significantly smaller wing) MK 103 pods might be more practical. (but then, so would a MK 103 nose cannon -and more likely to fit in the airframe than the BK37)


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## Shortround6 (May 17, 2015)

tomo pauk said:


> In case Germany gets way too much of the G&R 14N engines, stick them on the Ju 87.



The G&R 14N pretty much slammed into a brick wall at 1100hp. Even the post war version was only rated at 1180hp for take-off at 2650rpm. the pre-war/1940 versions pretty much being limited to 2360/2400rpm. Junkers started work on the Ju-87D in the Spring of 1940 and not only redid the engine mount/set up to take the Jumo 211J but modified the engine cowl and radiators, redesigned the canopy for less drag, redesigned the landing gear 'trousers' and enlarged the tail. All of this for what was viewed as an "interim' type. Spending engineering time an a Ju-87 variant that would be _less_ capable than the Ju-87B already in production doesn't seem like a good idea even if you can get a bunch of 14N engines. Production of the 87D starting in the spring of 1941 at which point any unit getting G-R powered JU-87s would be wondering what they did to get punished. 

The Germans were certainly planning to do _something_ with the G-R engines but plans seem a bit hazy. It was noted that G-R production as a whole was about 25% of what the Germans planned/anticipated. G-R managed to produce just enough to prevent mass reprisals from the Germans or having the bulk of the machinery hauled away.


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## Shortround6 (May 17, 2015)

When people propose building engines to foreign blueprints (Germans build Japanese engines) they may want to think about _doesn't_ get built. NO country in WW II involved in the fighting had spare engine building capacity going unused. Building several hundred engines for a 'special' project aircraft means several hundred other engines don't get built. The Germans were _trying_ to use the production capabilities of the countries the occupied. In some cases by looting them and sending the machine tools back to Germany to equip new or expanded factories in Germany and in other cases by continuing production of the original engines and in some cases by have the occupied factories built parts for engines that were shipped to German factories for final assembly. In a few cases the occupied factory built complete German engines to either supplement German production or free up the German factory for another project. Argus 411s being built by Renault during the war and production continuing after the war.


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## tomo pauk (May 17, 2015)

kool kitty89 said:


> ...
> 
> You'd have to make it DB-603 powered to manage a nose mounted cannon or resort to Hurricane IID style underwing pots. (but a BK37 is a good deal larger and heavier than the Vickers S and the Fw 190 has a significantly smaller wing) MK 103 pods might be more practical. (but then, so would a MK 103 nose cannon -and more likely to fit in the airframe than the BK37)



It is of course necessary to make sure that 3cm (or, even better, the 3,7cm, amount of ammo might be the problem) can fit between engine and pilot - the Yak-9T have had the cockpit removed 40cm back so the 37mm can fit. Then, hopefully, the Jumo 211F might be 'persuaded' for the job. 1st - try to see whether it is possible to have the engine cannon feature back, like it was true for the Jumo 211B. 2nd - take advantage of the low compression ratio in order to have the boost up to, say, 1.6 ata (and beyond). Looking at the power chart, it should give 1550-1600 PS on the sea level, ~1400 PS at 1km, and, in second gear, 1350 PS at 3.8 km (all values for 2600 rpm, 1.6 ata and no ram). That would not be power to compete vs. Western air forces, esp above 3 km, but it would come in handy for a fighter bomber of the Eastern front. Add some protection to the coolers. Fit the engine cannon, no fuselage guns of course, and 2cm in the wing roots. The AP shot will also make Il-2 drivers feel uncomfortable, armor protection won't cut against that threat. Such a Fw 190 wont be able to take off with 1800 kg bomb or a torpedo, but lighter bombs should be no problem.


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## kool kitty89 (May 17, 2015)

tomo pauk said:


> It is of course necessary to make sure that 3cm (or, even better, the 3,7cm, amount of ammo might be the problem) can fit between engine and pilot - the Yak-9T have had the cockpit removed 40cm back so the 37mm can fit. Then, hopefully, the Jumo 211F might be 'persuaded' for the job. 1st - try to see whether it is possible to have the engine cannon feature back, like it was true for the Jumo 211B. 2nd - take advantage of the low compression ratio in order to have the boost up to, say, 1.6 ata (and beyond). Looking at the power chart, it should give 1550-1600 PS on the sea level, ~1400 PS at 1km, and, in second gear, 1350 PS at 3.8 km (all values for 2600 rpm, 1.6 ata and no ram). That would not be power to compete vs. Western air forces, esp above 3 km, but it would come in handy for a fighter bomber of the Eastern front.


That engine arrangement seems like it would be attractive for Eastern Front fighters in general, though likely with the MK-103 replaced with the 108 or MG 151 along with reduced armor when not expressly intended for ground attack. 

Aside from the Fw 190, there's still some question of the Bf 109, but even given the Yak 9 managing it, repositioning the cockpit might not be practical in the small airframe. (either way, the low-alt Jumo 211F remains interesting, and the 109T's wing would be attractive for fighter-bomber use in general)



> Add some protection to the coolers. Fit the engine cannon, no fuselage guns of course, and 2cm in the wing roots. The AP shot will also make Il-2 drivers feel uncomfortable, armor protection won't cut against that threat. Such a Fw 190 wont be able to take off with 1800 kg bomb or a torpedo, but lighter bombs should be no problem.


For anti-armor use, I'd think AP ammo on the 15 mm MG 151 would be more useful.


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## Shortround6 (May 17, 2015)

Advantage the Russians had was that on the M-105 almost the entire space between the cylinder blocks was clear. Both the intake system and the exhaust was on the outside of the engine.






On the German engines space was made for a tube with a 70mm inside diameter. Which means your barrel _*cannot*_ exceed 70mm in diameter even if the barrel is in contact with the tube (not a good idea due to cooling and friction. )
For a 30mm gun that means your barrel walls can only be 20mm (or less) thick. Things get *real* interesting with a 37mm gun. 16mm thick barrel walls? or less? 

Now maybe the Germans _could_ have gone back to the drawing board and changed a few things to allow a bigger tube but it is still a tube. Russians _only_ hit a restriction when they get to the propshaft and gear case. last few feet of a barrel can be rather skinny as the pressure is rather low at that point.


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## Shortround6 (May 17, 2015)

kool kitty89 said:


> For anti-armor use, I'd think AP ammo on the 15 mm MG 151 would be more useful.




When trying to take out armor the goal is to destroy/kill what is _behind_ the armor, not just poke holes in the armor. The bigger the hole the more 'stuff' (metal that used to be in the 'hole') is flying around inside the vehicle. Even 37-40mm guns often failed to "kill" a tank with 1st or 2nd or even 3rd penetrating hit depending on where it hit. The 15mm is only moving about 56% as much "stuff" as a 20mm. Granted a round that doesn't penetrate at all doesn't do anything. 

This is one reason small anti-tank rifles fell out of favor. They often required multiple hits/penetrations to get a "kill" and while better "than nothing" that is faint praise indeed.


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## GrauGeist (May 17, 2015)

To add to that, if your in the air attacking armor, you only have a small window to aquire and hit your target. Needing multiple hits for a kill means perhaps several passes.

All this time, you have the sole undivided attention of ground forces who are not very happy at your presence.


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## kool kitty89 (May 18, 2015)

Shortround6 said:


> Advantage the Russians had was that on the M-105 almost the entire space between the cylinder blocks was clear. Both the intake system and the exhaust was on the outside of the engine.


An unusual feature (flathead engines aside) shared by the Hispano-Suiza 12Y.




> On the German engines space was made for a tube with a 70mm inside diameter. Which means your barrel _*cannot*_ exceed 70mm in diameter even if the barrel is in contact with the tube (not a good idea due to cooling and friction. )
> For a 30mm gun that means your barrel walls can only be 20mm (or less) thick. Things get *real* interesting with a 37mm gun. 16mm thick barrel walls? or less?


Did the space provided on the DB 603 increase that at all?




Shortround6 said:


> When trying to take out armor the goal is to destroy/kill what is _behind_ the armor, not just poke holes in the armor. The bigger the hole the more 'stuff' (metal that used to be in the 'hole') is flying around inside the vehicle. Even 37-40mm guns often failed to "kill" a tank with 1st or 2nd or even 3rd penetrating hit depending on where it hit. The 15mm is only moving about 56% as much "stuff" as a 20mm. Granted a round that doesn't penetrate at all doesn't do anything.


I was more referring to the Il-2 comment. For anti-armor I'd think the MK-103 would be the minimum, maybe the MG c/30L would have been usable on lighter armor (more so early-war).


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## Shortround6 (May 18, 2015)

The Germans were working on a version of the MK 103 to fit in the 70mm tube. 

View attachment 292764


This is the regular version. A bit shorter or longer barrel may not have been a big problem. Reducing the size of the barrel support and position of the gas tube would take more work. There was an awful lot of gun _behind_ the 70mm tube if they didn't. 

The problem with shooting down the IL-2 was getting a good firing angle on the armor. A lot of the armor was 4-6mm thick? but the impact angles were very shallow causing the projectiles to ricochet off. See: MG 151 cannon - Wikipedia

Germans had four different kinds of AP ammo for the MG 151/20. how wide spread some where may be subject to question. 

As for the high angle impact problem see this chart from originally posted here. http://www.ww2aircraft.net/forum/we...ftwaffe-cannons-machineguns-topic-6368-5.html






Not all projectiles behave the same but impact angles of less than 30 degrees to the surface of the plate get even more difficult.


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## bobbysocks (May 18, 2015)

wow that is tiny for a twin. you would figure being that small and relatively light it wouldnt take too powerful of engines to make it a fast, agile bird but guess not. i wonder what the performance would have been like if it had the same engines as a 110 ( if they would even fit)?


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## l'Omnivore Sobriquet (May 19, 2015)

1 - Allow for some expense and tighten quality control at the production lines of Gnome&R 14M engines.
2 - Try and convince the German ground crew that these aren't carton-cardboard failures, pretentious clocks, from a defeated country but instead some serious stuff that deserve dedicated work on the field.

By far the best solution.
non ?


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