Ju 87, but with radial engine?

[tomo pauk]

A small what if, certainly not of 'Gremany does this and they win the ww2' proportions.
But still: let's assume that RLM pushes on to have Ju-87 being powered by a radial engine, for reasons of perhaps to cover the bases is the supply of 1000+ HP V12 engines is not sufficient during the time of vast rearmament. We can recall that Ju 87As were powered by a 650+- HP engine, so even a humble 900-1000 HP radial is an improvement. The Ju 87B1 and R1 have gotten the 1000 HP Jumo 211A, the B2 and R2 have had the 1200 HP Jumo 211D.
Germany has in production a ~900 HP BMW 132, and 900-1000 HP Bramo 323 right before ww2 starts. Later, they can use the Polish and/or French radials. BMW 801 is also a possibility if it can be spared. Yes, a switch to the radials means something else gets axed, replaced by something else, phased-out or re-engined. Hs 126, 129, Do 17, Ju 52 are the likely candidates.
What might be the benefits and shortcomings here?

 

[Shortround6]

A small what if, certainly not of 'Gremany does this and they win the ww2' proportions.
But still: let's assume that RLM pushes on to have Ju-87 being powered by a radial engine, for reasons of perhaps to cover the bases is the supply of 1000+ HP V12 engines is not sufficient during the time of vast rearmament. We can recall that Ju 87As were powered by a 650+- HP engine, so even a humble 900-1000 HP radial is an improvement. The Ju 87B1 and R1 have gotten the 1000 HP Jumo 211A, the B2 and R2 have had the 1200 HP Jumo 211D.
Germany has in production a ~900 HP BMW 132, and 900-1000 HP Bramo 323 right before ww2 starts. Later, they can use the Polish and/or French radials. BMW 801 is also a possibility if it can be spared. Yes, a switch to the radials means something else gets axed, replaced by something else, phased-out or re-engined. Hs 126, 129, Do 17, Ju 52 are the likely candidates.
What might be the benefits and shortcomings here?

Except for training it isn't going to work for very long.
" We can recall that Ju 87As were powered by a 650+- HP engine, so even a humble 900-1000 HP radial is an improvement"
Yes but the Ju 87s weren't really that capable an airplane, By Poland they were all in training schools.
No armor, no protected fuel tanks, one 7.9 fixed machine gun, not two, almost 40mph slower than a Ju 87B.
So yes, you can improve it. But if it won't come close to the JU 87B what is the point?

Polish radials are rather dubious from a supply stand point and since the Germans were making around 60 Ju 87s a month in 1939 you need much more than Poland could supply even assuming you can get Polish engines after the war, (factory is undamaged, workers are still there, tools have not been sent to Germany).
Only French engine is the GR 14N. and since is has more drag and less power than the Jumo 211Da engine it is hard to see any advantage.

 

[GTX]

I have seen someone model a Ju-87 with a BMW801 in the nose years ago. Will try to find some photos.

 

[PFVA63]

Hi,
Here is an article about the Ha-137, which is stated to have been a competitor to the Ju-87. In the article, it shows an image of a variant of that plane with a licensed P&W Hornet Radial.

Regards

Pat

Dive Bomber That Lost Out to the Celebrated Stuka

PS. This link (Blohm und Voss Ha 137 - Destination's Journey) indicates that three of the prototypes were actually powered by BMW 132 radials (which I guess were derivatives of the Hornet per BMW 132 - Wikipedia)

 

[tomo pauk]

Except for training it isn't going to work for very long.
" We can recall that Ju 87As were powered by a 650+- HP engine, so even a humble 900-1000 HP radial is an improvement"
Yes but the Ju 87s weren't really that capable an airplane, By Poland they were all in training schools.
No armor, no protected fuel tanks, one 7.9 fixed machine gun, not two, almost 40mph slower than a Ju 87B.
So yes, you can improve it. But if it won't come close to the JU 87B what is the point?

One point might be that, vs. Jumo 211 installation, there is a save of 150-200 kg of dry weight in case of the 9-cyl radials, plus 100 kg worth of cooling system. That can allow for greater bomb carrying capacity to be capitalized already before the ww2.
Another point is that there is now more Ju 211s around, so the He 111 can have them earlier, that in return means the DB 601s are no longer in short supply in 1939-40.

Only French engine is the GR 14N. and since is has more drag and less power than the Jumo 211Da engine it is hard to see any advantage.

The 14N has the advantage of being as good as free. Another might be that making one 14N should be easier than making two 14Ms; yes, the G&R contribution to the German war effort was not great historically.
Power deficit of 14N vs. 211D is minimal, and Ju 87 is already about as draggy as a monoplane can be. 14N makes 10-15% more power than the Jumo 211A, found on early Ju 87Bs and Rs, that were still eventually rated for 1000 kg bomb (and drop tanks in case of the R1). It is also tad lighter, even more once we count the cooling system weight.

 

[Shortround6]

One point might be that, vs. Jumo 211 installation, there is a save of 150-200 kg of dry weight in case of the 9-cyl radials, plus 100 kg worth of cooling system. That can allow for greater bomb carrying capacity to be capitalized already before the ww2.

I am not sure that the weight difference is all that great. The BMW was a bit lighter than Bramo but it was over 1150lbs and the Bramo was just about 1200lbs. Early Jumo 211 was under 1300lbs, plus of course the cooling system/water.
The BMW used a single speed supercharger so you can play a few games with the supercharger gears and the power at altitude.
The Bramo came both single speed and two speed. And the single speed could also come with different supercharger ratios.
The two speed version was over 1300lbs and made 1000hp at sea level. (1200hp version came late and needed water injection)

Power deficit of 14N vs. 211D is minimal, and Ju 87 is already about as draggy as a monoplane can be. 14N makes 10-15% more power than the Jumo 211A, found on early Ju 87Bs and Rs,

By the time you have access to G-R 14N engines the Ju 87s are being built with the 1200hp Jumo 210s and the higher power 211s are in the pipeline although delayed.

G-R promised a lot but never delivered more than 1180-1200hp take-off by the time France fell in a production engine.

 

[Sons of Anzac]

Just keep the Henschel 123 in production and undertake an update for extending range and power.

 

[tomo pauk]

Just keep the Henschel 123 in production and undertake an update for extending range and power.

I'd prefer curtailing both Hs 126 and 123 production (granted, Hs 123 is out of production by mid-1937), as well as not proceeding with the Hs 129 all together, with Henschell making the Ju 87s under licence instead.

PS. This link (Blohm und Voss Ha 137 - Destination's Journey) indicates that three of the prototypes were actually powered by BMW 132 radials (which I guess were derivatives of the Hornet per BMW 132 - Wikipedia)

The BMW 132A was pretty much the equivalent of the Hornet the BMW bought licence for. Later 132s were modified and improved, and made better power.

 

[Shortround6]

I'd prefer curtailing both Hs 126 and 123 production (granted, Hs 123 is out of production by mid-1937), as well as not proceeding with the Hs 129 all together, with Henschell making the Ju 87s under licence instead.



The BMW 132A was pretty much the equivalent of the Hornet the BMW bought licence for. Later 132s were modified and improved, and made better power.

And that is a major problem. Once you get passed the Jumo 210 you are trying to substitute 27 liter air cooled engines for 35 liter liquid cooled engines.

you are trying to make do with about 80% of the power (or less) most of the time. there were periods were things were closer together.

 

[tomo pauk]

And that is a major problem. Once you get passed the Jumo 210 you are trying to substitute 27 liter air cooled engines for 35 liter liquid cooled engines.

you are trying to make do with about 80% of the power (or less) most of the time. there were periods were things were closer together.

I'm trying to make engines switch, so there is less pressure on the 'premium' engines Germany was set to produce in the late 1930s. The suggested engines can make 85-95% of power the Jumo 211s were making from late 1938 to the late 1939 while also offering the weight reduction - that can come in handy on a bomb lugger.
You can also note that I'm willing to kill off the military aircraft of dubious value, like the Hs 126. Or the late bloomer, Hs 129. Stukas produced at Henschell, and powered by radial engines will improve the situation with ground attack and short-distance recon both for Luftwaffe and their allies.

I am not sure that the weight difference is all that great. The BMW was a bit lighter than Bramo but it was over 1150lbs and the Bramo was just about 1200lbs. Early Jumo 211 was under 1300lbs, plus of course the cooling system/water.

Jumo 211A was at 615 kg, or 1355 lbs. Cooling system - another 300+ lbs (I have the weight figure for the P-39, 320 lbs)? This is 500+ lbs combined vs. BMW 132, or 450+ lbs vs. the Bramo. 200-250 kg weight saved, or weight of a serious bomb load for an early Ju 87.
Jumo 211D was at 660 kg, or around 1455 lbs. Yes, these offered another 200 HP over the 211A. Weight vs. the radial installation is up by another 100 lbs.

By the time you have access to G-R 14N engines the Ju 87s are being built with the 1200hp Jumo 210s and the higher power 211s are in the pipeline although delayed.

G-R promised a lot but never delivered more than 1180-1200hp take-off by the time France fell in a production engine.

The Ju 87 with a current 14N in the nose (-30s or -40s) should do anything the historical Ju 87B2 or R2 can do, while taxing less on German supply of work and raw materials. It can have two MK 101s installed and go tank plinking. Weight saved from not having the liquid cooling system can go into the improvement of protection vs. ground fire.

 

[Shortround6]

The suggested engines can make 85-95% of power the Jumo 211s were making from late 1938 to the late 1939 while also offering the weight reduction - that can come in handy on a bomb lugger.
You can also note that I'm willing to kill off the military aircraft of dubious value, like the Hs 126. Or the late bloomer, Hs 129. Stukas produced at Henschell, and powered by radial engines will improve the situation with ground attack and short-distance recon both for Luftwaffe and their allies.

An awful lot depends on precise timing. I also made an error in my calculation for displacement, The Jumo 211 was almost 30% larger in displacement.
You can kill off the Hs 126, again the problem is when, mostly.
The Hs 126A used the BMW 132 engine of 880hp for take-off and 870hp at 8,200ft. These replaced the HE 45 and He 46 aircraft and stayed in production until the summer/fall of 1939.
This is when the Hs 126B showed up and used the Bramo 323 but they used several different versions. The early used engines with 850hp for take off and the later ones (and production of the HS 12B went through 1940) had 900hp for take-off. They are supposed to have two speed superchargers with FTH of 13,780ft.
However information is all over the place.
At some point the 323 was rated at 1000hp for take-off but not the engines used in the Hs 126.
The Fw 200 got 1000 hp engines (1200hp with water injection ) in 1940? Fw 200C-3?

Jumo 211A was at 615 kg, or 1355 lbs. Cooling system - another 300+ lbs

A lot depends of the state of "fit". One source for the BMW 132 gives weights for the fuel pump (?), starter, generator, air pump, etc.
V-12s generally need less weight for exhaust system. Granted not as heavy as the cooling system.

The Ju 87 with a current 14N in the nose (-30s or -40s) should do anything the historical Ju 87B2 or R2 can do, while taxing less on German supply of work and raw materials. It can have two MK 101s installed and go tank plinking. Weight saved from not having the liquid cooling system can go into the improvement of protection vs. ground fire.

You are looking for the 14N 48/49. anything older has less power, and it didn't get any better.
and the only real weight saving is the cooling system.

 

[tomo pauk]

You can kill off the Hs 126, again the problem is when, mostly.
The Hs 126A used the BMW 132 engine of 880hp for take-off and 870hp at 8,200ft. These replaced the HE 45 and He 46 aircraft and stayed in production until the summer/fall of 1939.

Ju 87A (yes, it had it's limits) was introduced in service in 1936. That is probably before the Hs 126's 1st flight, that happened on 13th Dec 1936; the 126 was introduced in service in early 1938.
So I'd kill the Hs 126 some time in 1936.

(manual for the Hs 126A-1 from May 1939 says that engine used is the Bramo 323A-1 or A-2; 87 oct fuel used; for take off the A-1 was rated for 2450 rpm and 1.36 ata, the A-2 for 2500 rpm and 1.45 ata; 900 HP should be the power for the later engine going by the Dornier data; A-2 had the rated altitude of 4.7 km with ram on Do 17, making there 840 HP for 5 minutes)

At some point the 323 was rated at 1000hp for take-off but not the engines used in the Hs 126.
The Fw 200 got 1000 hp engines (1200hp with water injection ) in 1940? Fw 200C-3?

1000 HP for take off was supposed to provide the Bramo 323P as installed on the Do-17Z. Dornier's docs, dated 4th April 1938, note 1050 HP for take off on that engine, referring at Bramo's doc from 5th March 1938 as a source - perhaps Bramo over-promised by 50 HP?
With 100 oct, the 323R-2 was making 1100 HP in 1940.

BMW 132 achieving 1000 HP was a result of over-boosting by using 100 oct fuel for take off on the Fw 200 in 1940 (similar idea as used on the Blenheim IV, with separate 'take off tanks' and 'cruising tanks').

You are looking for the 14N 48/49. anything older has less power, and it didn't get any better.
and the only real weight saving is the cooling system.

The 14N -20/-21, -24/-25, -30/-31 and -38/-39 ('negative'/'positive' rotation) were also supposed to make 1000 HP and a tad more, per G&R manual. The -30/-31 were the lowest-performing of the lot, being decidedly low-altitude engines.

 

[tomo pauk]

his is when the Hs 126B showed up and used the Bramo 323 but they used several different versions. The early used engines with 850hp for take off and the later ones (and production of the HS 12B went through 1940) had 900hp for take-off. They are supposed to have two speed superchargers with FTH of 13,780ft.

Note the comment at the above post - the Bramo 323A was with 1-speed supercharger. The 1st 323 with 2-speed S/C was the N version, with P and R following.

 

[Shortround6]

I am not so sure you can stop production of the Hs 126, cut back maybe.
A radial Ju 87 may not be able to perform all of the same roles.

The Hs 126 used almost the same wing area as the Ju 87, however the plane's empty weight was 4480lbs vs 5980lbs (Ju 87B-1) and the max loaded for the Hs 126 was 7,209 lbs vs 9,560lbs.
The Hs 126 did some of the same roles as the Lysander, It was noted for it's short field performance (nowhere near that of the Fi 156 ) it was as much due to the low wing loading as any tricky bits on the wing. Perhaps there is enough room in the cockpit to mount the camera in the Ju 87.
A radial Ju 87 is a better attack plane, but would it do as well for other things?
The Hs 126 was replaced by the Fw 189.

 

[special ed]

Camera mounted in belly. See the Hs 126 thread.

 

[tomo pauk]

A radial Ju 87 may not be able to perform all of the same roles.

The Hs 126 used almost the same wing area as the Ju 87, however the plane's empty weight was 4480lbs vs 5980lbs (Ju 87B-1) and the max loaded for the Hs 126 was 7,209 lbs vs 9,560lbs.

So far so good - having a better payload vs. empty_weight ratio is usually a good thing, unless trying to break some climb records.
(max load of the B-1 went up as war progressed)
German wikipedia says 2032 vs. 2750 empty weight, Hs 126 vs. Ju 87B. The radial Ju 87 will shave some 200-250 kg of the weight.

The Hs 126 did some of the same roles as the Lysander, It was noted for it's short field performance (nowhere near that of the Fi 156 ) it was as much due to the low wing loading as any tricky bits on the wing. Perhaps there is enough room in the cockpit to mount the camera in the Ju 87.

To me, Lysander and Hs 126 shared the same shortcomings - small bomb load as bombers (German wikipedia notes just one 50 kg bomb for the 126 - ??), too expensive & too big as tactical recons.
Stuka is a big aircraft, a camera will fit in the cockpit (if it is not too big), and there is the a place where the central bomb was. Short-field abilities will require a minimal bomb load to be carried.

 

[Shortround6]

Most sources say the HS 126 will hold two five bomb magazines for 10kg bombs behind the rear cockpit, and/or the single 50kg bomb under the left side of the fuselage. total 150kg?
Bombing was not the primary role. The Hs 126 was also the replacement for the He 46.

no fixed forward firing gun, single mg in the rear cockpit and up to twenty 10kg bombs inside the plane. export versions got cowls and different engines.

Among the main roles were recon and artillery spotting. In the mid to late 30s the AA situation was not to bad and anything could fly was sometimes used to bomb.
The German biplane fighters could carry 5-6 10kg bombs inside on a rack/dispenser.

Like the majority of the worlds short range recon/observation machines they preferred a high wing.