D-B produced a total of 71,478 engines of which 42,400 were D-B605s.
U.S. Strategic Bombing Survey Aircraft Division Industry Report
Replace Me-109 with Me-155?
- Thread starter davebender
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D-B produced a total of 71,478 engines of which 42,400 were D-B605s.
U.S. Strategic Bombing Survey Aircraft Division Industry Report
- Thread starter
- #182
davebender
1st Lieutenant
Mk103 3cm AP Penetration.
AP-T(WC)
70 mm/60°/300 m
100 mm/90°/300 m.
Typical WWII top armor was 20 to 25mm thick. So the 70mm penetration achieved at a 60 degree angle should work just fine.
Civettone
Tech Sergeant
Interesting, I never did the maths. Could it be that slower attack aircraft like the Il-2 or Ju 87 used a steeper dive?
Anyway, the sloping armour was think enough to stop the shells from aircraft guns anyway, regardless of the angle. The deck and top turret armour was not sloped but would always be hit in a very shallow angle.
As a side note, the less accurate rockets have better penetration and do not rely on the right angle. Unless of course you are talking about the hollow-charged rockets like the Panzerblitz which would not be a very reliable weapon if you ask me.
Kris
Civettone
Tech Sergeant
Those figures seem dubious. What I have is 75 mm vertical at 300 m. But with an angle of 15 degrees a Sherman top armour would go from 25 to 75 mm.
Mk103 3cm AP Penetration.
AP-T(WC)
70 mm/60°/300 m
100 mm/90°/300 m.
Typical WWII top armor was 20 to 25mm thick. So the 70mm penetration achieved at a 60 degree angle should work just fine.
Even though those figures seem nice I still wonder why they went over to the 3.7 cm? And then the 5, 5.5 and 7.5 cm?
Kris
Shortround6
Major General
Mk103 3cm AP Penetration.
AP-T(WC)
70 mm/60°/300 m
100 mm/90°/300 m.
Typical WWII top armor was 20 to 25mm thick. So the 70mm penetration achieved at a 60 degree angle should work just fine.
Not a chance.
To get the 90 degree penetration you would have to be in a vertical dive. To get the 60 degree angle of impact on the roof you would have to be in a 60 degree dive.
Do you really want to be in a 60 degree dive 300 meters from the ground?
at a 30 degree angle of impact (30 degree dive) the path the projectile must take through 25mm armor is actually 50mm in length and this does NOT factor in any tendency to skid or ricochet, or any other misbehavior of the projectile.
The reason the these guns worked, at least to some extent, was that "typical" WW II top armor wasn't 20-25mm thick but more like 15-20 mm thick.
20-25 mm armor was more in the area of Tiger tank or KV/JS thickness.
MK IVs, Shermans, Cromwells and T-34s had top armor in the 13 -20mm range in many locations. Some tanks having different thickness on the turret roof vs the front part of the hull roof and engine decks being even thinner.
Since the ground guns could deal with the medium tanks fairly well it was the Heavy tanks that the ground troops wanted help with.
If the 30mm gun could deal with tanks just fine why did the Germans spend so much time and effort trying to use 50mm and 75mm anti-tank guns from planes?
- Thread starter
- #186
davebender
1st Lieutenant
What do you mean by "So Much"? As far as I'm aware German attempts to use aircraft mounted guns larger then 3.7cm in size were experiments. None of those installations were employed in large numbers. In fact not even the Ju-87G (with 3.7cm cannon) was produced in large numbers.
Civettone
Tech Sergeant
They weren't produced in large numbers because fighters got the priority.
But again, why move to the 3,7 cm if you think the 3 cm was sufficient?
Kris
But again, why move to the 3,7 cm if you think the 3 cm was sufficient?
Kris
billswagger
Airman 1st Class
- 256
- Mar 12, 2009
any info on penetration for the mk103 HE round?
They probably went for larger rounds to compensate for the shallower angle and to lower trigger times seeing as ground attack on tanks and armored targets was usually more dangerous.
Bill
They probably went for larger rounds to compensate for the shallower angle and to lower trigger times seeing as ground attack on tanks and armored targets was usually more dangerous.
Bill
Shortround6
Major General
Well, they "experimented" with both 50mm guns and 75mm guns on the Ju 88. They "experimented" with the 75mm gun on the HS 129. They even experimented with putting the 75mm cannon in the He 177. Now each of these "experiments" used from 5 to 20+ airframes depending on which source you believe. Three different projects totaling from 20+ to 40+ plus aircraft and you don't consider it a lot of effort?
Shortround6
Major General
Against most armored vehicles the 30mm would have been sufficient because the basic idea is to shoot the tank, armored car/halftrack in the back or side were the armor is much thinner than on the front and you can get a descent angle of attack.
But military requirements tend to stress worst case scenarios and like I said, they wanted to aircraft to take out the heavy tanks. the heavy tanks were armored to withstand 30-50mm guns (or even larger) pretty much all around at medium to long range. But if you could get the 50-75 mm gun behind the tank at medium to close range it should work. And the best way to do that was by airplane. Except that none of the airplanes available had both the structural strength needed to withstand the firing and the performance necessary to carry the weight in a combat environment. bomber or fighter bomber that comes and drops it's bombs is 1/2 to 2 tons lighter after bomb release to help with evasive maneuverers as it leaves the target zone. One of these gun carrying planes is leaving just about as heavy as it went in (minus a few shells) so it has no more speed, climb, or turning ability after the strike than it did went when in with surprise on it's side.
But military requirements tend to stress worst case scenarios and like I said, they wanted to aircraft to take out the heavy tanks. the heavy tanks were armored to withstand 30-50mm guns (or even larger) pretty much all around at medium to long range. But if you could get the 50-75 mm gun behind the tank at medium to close range it should work. And the best way to do that was by airplane. Except that none of the airplanes available had both the structural strength needed to withstand the firing and the performance necessary to carry the weight in a combat environment. bomber or fighter bomber that comes and drops it's bombs is 1/2 to 2 tons lighter after bomb release to help with evasive maneuverers as it leaves the target zone. One of these gun carrying planes is leaving just about as heavy as it went in (minus a few shells) so it has no more speed, climb, or turning ability after the strike than it did went when in with surprise on it's side.
- Thread starter
- #191
davebender
1st Lieutenant
Did any German AT aircraft use the 3.7cm weapon except the Ju-87G? I believe the Hs-129 and Fw-190F both mostly used the 3cm Mk103 cannon.
Civettone
Tech Sergeant
Bill, what do you mean by lower trigger time?
Dave, the Fw 190F did not use the MK 103 as the wings couldnt handle the recoil. The Hs 129 was armed with the 3,7 cm but most stayed with the 3 cm. With the Bk 5 was only experiment wise while the 7,5 cm was more common.
I also think that the Hs 129 with the lighter 3,7 cm Flak 43 would have been the best option. The Hs 129 had a center mounted gun which would have been much more accurate than the wing guns of the Ju 87. The positive side of the Ju 87G is that it could be turned into a Ju 87D in a minute.
Kris
Dave, the Fw 190F did not use the MK 103 as the wings couldnt handle the recoil. The Hs 129 was armed with the 3,7 cm but most stayed with the 3 cm. With the Bk 5 was only experiment wise while the 7,5 cm was more common.
I also think that the Hs 129 with the lighter 3,7 cm Flak 43 would have been the best option. The Hs 129 had a center mounted gun which would have been much more accurate than the wing guns of the Ju 87. The positive side of the Ju 87G is that it could be turned into a Ju 87D in a minute.
Kris
davparlr
Senior Master Sergeant
A slice in time
August, 1941, production delivery of Fw-190A-2 begins.
Fw-190A-2, engine BMW 801C-2, 1539 hp, dry weight 2226 lbs
Bf-109F, engine DB 601E, 1350 hp, weight 1620 lbs (1320 lbs + 300 lbs cooling system-ala P-39)
P-47B, engine PW R-2800-21, 2000 hp, dry weight 2265 lbs
With these numbers, the power to weight ratio of the three aircraft is as follows:
BMW 801C-2 .69 hp/lb
DB 601E .83 hp/lb
PW R-2800 .88 hp/lb
It was already apparent that the radial had considerable potential that the Germans could use. They should have pulled a Russian reverse engineering on a captured R-2800. Can you imagine an Fw-190 with an R-2800-18W equivalent (F4U-4) engine in the fall of '44. It would have flown circles around the D-9 at any altitude, and, most other aircraft, including the P-51D at high altitude, which the D-9 could not do.
It seems PW did not have such a problem, maybe if the Germans had emphasized the radial more they would have also.
davebender said:
Shortround6 said:
These are confusing comments. Both the P-47 and, especially late model, P-38s were effective and reliable turbocharged fighters, therefore, apparently turbochargers compact enough for fighters were made. These were big aircraft, but still fighters. However, Shortround is correct in that the physics of compressing the massive amount of air for these large engines prevented compact and efficient turbochargers to fit small airframes.
NZTyphoon
Airman 1st Class
One thing most people are forgetting is that tanks, even something as big as a Tiger II or JS 2/3, are still small targets for a fast fighter bomber, especially to one flying at low altitude. Added to that are the problems of camouflage and dispersal - a tank could be even harder to see if camouflaged, or against a backdrop of trees etc.
A fast F-B such as the Fw 190 was harder to hit from the ground, hence better able to survive than something flying low and slow, but it also meant it was harder to hit ground targets - trying flying at (say) 300 mph at low altitude while aiming at a small target like a tank, then further reduce the target area to the turret roof or engine compartment!
One way of compensating was to have a weapon with a high rate of fire (eg: the GAU-8 30mm cannon of an A-10), which could guarantee multiple strikes in a small area, or to fly slower and have a larger weapon which had more chance of a one-shot kill, such as the 50 or 75mm A-T gun carried by the likes of the Hs 129. The 37 mm cannon carried by the Ju 87G was effective (Gustav Rudel), but it came at a cost of high attrition. Does anyone know how many Panthers and Tigers were knocked out by IL-2s alone? How many IL-2s did it cost to knock out one German heavy tank? How many JS-2s were knocked out by Ju 87Gs?.
BTW The Hs 129B-3 had a 7.5cm BK (a modified PaK 40) and it was more than "experimental", going operational in 1944, unlike the He 177 which stayed experimental.
Other aircraft to carry heavy weapons:
B-25G and H Mitchell (75 mm)
Piaggio P-108B Heavy Bomber (105 mm howitzer)
Mitsubishi Ki-109 (75 mm)
Me 410A-1/U4 (50 mm)
Glider
Captain
Mossie with the 57mm AT gun
Hurricane with the 40mm
Hurricane with the 40mm
NZ, I guess the true numbers of heavy German or heavy Soviet tanks destroyed out by either IL-2s, Hs 129s or Ju 87 Gs is low. I think even the numbers of medium tanks such as Pz IV or T-34 claimed destroyed is too high by a very large margin and that includes Rudel.
The attack aircraft's capability to destroy tanks was probably good when compared to fighter bombers of the time, but that's about it. For practical purposes they could really only hope to disable them (damaging the tracks) or suppress their movement. For these purposes, small to medium bombs, rockets and medium sized cannons are sufficient. My personal opinion. I don't think investing in 5 cm or larger cannons on a large scale was worth the trouble. Especially the ammo needed (Wolfram) was much better spent with AT guns on the ground.
That is not to say I would solely go with fighter bombers instead. I think the experience in late '44 has shown that these are too vulnerable to light AAA. That's why I overall think the Fw 190 F was a good choice: A good fighter bomber with decent armor but enough speed down low to make interception a very hard job.
The attack aircraft's capability to destroy tanks was probably good when compared to fighter bombers of the time, but that's about it. For practical purposes they could really only hope to disable them (damaging the tracks) or suppress their movement. For these purposes, small to medium bombs, rockets and medium sized cannons are sufficient. My personal opinion. I don't think investing in 5 cm or larger cannons on a large scale was worth the trouble. Especially the ammo needed (Wolfram) was much better spent with AT guns on the ground.
That is not to say I would solely go with fighter bombers instead. I think the experience in late '44 has shown that these are too vulnerable to light AAA. That's why I overall think the Fw 190 F was a good choice: A good fighter bomber with decent armor but enough speed down low to make interception a very hard job.
And on what fuel? 87 octane? Otherwise that comparison is rather useless and the 801 D should've been taken: 1,677 hp for the same weight: .75 hp/lb
I guess you mean the power to weight of the engines. The contemporary fighters actually powered with these engines had very different power to weight ratios. Installing the not-fan-cooled 2800-21 would've meant a completely different and I'd say less drag-efficient cowling. R-2800 was also larger in diameter (only slightly though). Then there's the other not adressed questions: Fuel? Efficiency? Alloys?
The resulting aircraft may look much different than the real Fw 190 did.
And the reality in 1942 was that the existing Fw 190 with its BMW 801 D held up well with contemporary P-47s (and even early Hellcats and F4Us).
I don't know where to start: Did Germany even get the opportunity to have a detailed look at R2800s before 1942? Reverse engineering and industrialization in less than 2 years without detailed drawings, specifications? You'd take all these risks in 1942 Germany over developing satisfactory homegrown engines?
All the Jumo 213 needed was a better supercharger (which it got eventually, but too late) for pretty much the same result.
There were several improved versions of the BMW 801, too. The 801 E was a good improvement, increasing power by a good 200 KW and possibly more because the exhaust problems of the D were fixed. This also would've given the 801 a more stable, quiet run. The E version was to enter production in 1943 but didn't for several reasons. Instead they skipped it for the F. The F version had 2,367 hp, even 2,564 in the latest development. But it came too late. 20/20 hindsight. In 1942 there was a good chance the BMW 801 would have a normal lifecycle with the E and F (supercharged) and T (turbocharged) versions. Afterall the reality is not too far from it, but unfortunately the E was missing at a time when there was massive need for it (late 43 and 44).
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Shortround6
Major General
Quite right.
Originally Posted by davebender
"Specifics trump generalities every time. Let's look at historical German aircraft engines available during 1941."
August, 1941, production delivery of Fw-190A-2 begins.
Fw-190A-2, engine BMW 801C-2, 1539 hp, dry weight 2226 lbs
Bf-109F, engine DB 601E, 1350 hp, weight 1620 lbs (1320 lbs + 300 lbs cooling system-ala P-39)
P-47B, engine PW R-2800-21, 2000 hp, dry weight 2265 lbs
With these numbers, the power to weight ratio of the three aircraft is as follows:
BMW 801C-2 .69 hp/lb
DB 601E .83 hp/lb
PW R-2800 .88 hp/lb
At this point in time the BMW is just introducing it's first production model. The DB series is on what? it's 5th or 6th or 7th version, at any rate it is 4-5 years into it's production life and development cycle. The R-2800 is on it's second seres, the "A" series were 1850 hp engines. Following the normal progression of things later versions of the BMW should have offered more power while the DB was closer to being tapped out without going to extremes like changing to the 605 series.
I have no idea why the BMW was so heavy. At these numbers it has one of the worst power to weight ratios of any large radial engine built by anybody during all 6 years of WWII. I am not sure if the BMW's weight may include some parts or accessories not normally included in the "dry" weight. And "dry" usually doesn't mean just the absence of coolant and oil. It also means the absence of such things as starters, exhaust manifolds and pipes, vacuum pumps, generators and even in some cases variable pitch propeller controls in addition to other accessories. many of these things changed from installation to installation so the "dry" weight may be the only fair way to compare engines but it is far from being the installed weight.
Some times the weight of the BMW as given in some sources is the weight of the "power egg" which is much heavier. I don't know how much the cooling fan contributes to the weight or if there are another bits/pieces that are included in the "dry" weight that are not included in the other engines weights.
I had assumed that Mr. Bender was aware of both of those aircraft in addition to the bomber installations. I thought he was referring to installations that would be even more compact.
