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Starting with the basic design of the Ju88 in 1935, how would you optimize it for speed with a minimum of 900kg internal payload and 1000 mile minimum range?
Junkers Ju 88 - Wikipedia, the free encyclopedia
Ju-88, Ju-188, Ju-288, Ju-388, Ju-488, .... Ju-888
http://moderndrawings.jexiste.be/WW...anes/Axis/1-Germany/4-Bombers/Ju-88S-1/p1.jpg
Perhaps laminar flow wing from the beginning?Was there any problem with wing profile of the Ju 88? Airfoil, thickness?
As a brief exploration, I offer this.
Take a Ju 88 A-4 as out starting place. Let's say you want the new Ju 88 to be able to go 420 mph at best altitude to sort of match the P-38J/L.
1. Max speed was 317 mph at 17,389 feet on two engines of 1,400 HP each. I chose Wiki for these numbers, but any
numbers will do to show the end result.
2. To make the same aircraft go 420 mph would take 6,512 HP is there was no change in frontal area.
3. If we decrease the frontal area by 20%, the required power would fall to 5,209 HP.
3. So, if the engines can go from 1,400 HP each to 2,500 HP each AND if we decrease the frontal area by 20%, we can make it. Getting the engiens in 1939 would be impossible. When they WERE avialable, it's is doubtful whether or not a decrease in frontala rea of 20% would render the new aircraft a useful bomber with good internal payload, but you never really know until you try it.
From this it should be clear that the only way to make the Ju 88 perform like a P-38 would be a major redesign that would probably render it not suitable as a bomber with impressive internal capacity.
S-3
The S-3 was the last model of Ju 88 bomber to see production. The BMW radials of the S-1 and S-2 were replaced by Jumo 213A 12 cylinder liquid cooled inline engines, with turbo-superchargers and GM-1 boost. These engines could provide 2,300hp with wartime emergency boost, and also gained 340 pounds of thrust from their carefully designed exhausts. The S-3 had a top speed of 382mph at 27,900 feet, but although a small number did enter service in late 1944, they arrived at a time when virtually every German bomber was grounded due to lack of fuel.
1935 is not too late to change wing position from low to high. That way the bomb bay can be of decent size, unrestricted, so even the big bombs can be carried internally.
As a brief exploration, I offer this.
Take a Ju 88 A-4 as out starting place. Let's say you want the new Ju 88 to be able to go 420 mph at best altitude to sort of match the P-38J/L.
1. Max speed was 317 mph at 17,389 feet on two engines of 1,400 HP each. I chose Wiki for these numbers, but any
numbers will do to show the end result.
2. To make the same aircraft go 420 mph would take 6,512 HP is there was no change in frontal area.
3. If we decrease the frontal area by 20%, the required power would fall to 5,209 HP.
3. So, if the engines can go from 1,400 HP each to 2,500 HP each AND if we decrease the frontal area by 20%, we can make it. Getting the engiens in 1939 would be impossible. When they WERE avialable, it's is doubtful whether or not a decrease in frontala rea of 20% would render the new aircraft a useful bomber with good internal payload, but you never really know until you try it.
From this it should be clear that the only way to make the Ju 88 perform like a P-38 would be a major redesign that would probably render it not suitable as a bomber with impressive internal capacity.
Now you have the main spar and wing box routed through the area the rear observer/gunner's chest would normally be. Now we either have to drop one or two crew members or move the crew cabin forward and the knock on effect of this is likely a need for greater tail area or tail length that will cost us a little in speed due to extra weight drag. It should work however in the sense of offering higher penetration speeds (due to internal bombs) at the cost of slightly lower egress speeds. With the bombs now carried internally and without the internal fuel capacity offered by the bomb bays one would need to use drop tanks for longer ranged missions, that should be OK so long as they can be jettisoned early enough in the mission for it to prevent enemy interception.
There is an argument that by having a bomb bay one thickens the fuselage and increases its weight and that these costs are so high one is better of with external carriage. Just look at modern fighter bombers.
The Ju 88 is too big to be as fast as the Mosquito until late 1944 or early 1945 when bigger engines as powerful as the RR Grifon become available to German builders.
The BMW-801 was in the 1500-1600 power range in 1941, plus the Jumo 211s the bulk of Ju-88s employed had worse altitude performance than the contempoary DB-601s (and 605s).Uh, starting in 1935 you have crap for engines. You aren't going to get 1000-1200hp engines until 1939/40, you aren't going to get 1200-1400hp until 1941, You aren't going to get 1500-1600hp until 1942.
How about a Misquito class aircraft for 1935-1942 standards at least? Similar emphasis on limiting unnecessary size, weight, and bulk. No compromises for including defensive armament and limited to just two crew members.It did pretty good speed wise but what are you giving up for operational capability (things like vision).
Couldn't the existing wing configuration still have allowed for the ability to carry some larger bombs (even if not using the space as efficiently), or at least allow for that if it was planned for from the start? (that and adopting a bulged bomb bay for special heavy bomb runs like the Mossie did would make more sense than using external racks)1935 is not too late to change wing position from low to high. That way the bomb bay can be of decent size, unrestricted, so even the big bombs can be carried internally. Improves both top and cruising speed, along with range/radius when bombed up, vs. bombs being carried externally. I'd go with wing of ~50 sq m, and try to avoid increase in the size as the development progresses. The switch from annular radiators towards leading edge ones should be attempted, at least once it is recognized that British and/or Soviets are introducing that.
They could have gone with a symmetrical NACA (or other airfoil), less lift but less drag per area too, and less parasitic drag. (maybe a slightly higher critical mach number, but that's also dependent on thickness ratio)I know this is a what if, but going for a laminar flow wing for an aircraft conceived in 1935 is really pushing it
Junkers can shop at NACA if they want. Supermarine did so, so did NAA, Grumman, Focke Wulf, Lavotchkin etc. A not too thick wing of NACA 230 series will provide both benign flight characteristics and useful turn of speed.
What if you take reduced weight into account on top of reduced drag area and make the comparison more akin to the 1939 YP-38 at medium altitude? (or Fw-187 with DB-600s)As a brief exploration, I offer this.
Take a Ju 88 A-4 as out starting place. Let's say you want the new Ju 88 to be able to go 420 mph at best altitude to sort of match the P-38J/L.
3. So, if the engines can go from 1,400 HP each to 2,500 HP each AND if we decrease the frontal area by 20%, we can make it. Getting the engiens in 1939 would be impossible. When they WERE avialable, it's is doubtful whether or not a decrease in frontala rea of 20% would render the new aircraft a useful bomber with good internal payload, but you never really know until you try it.
From this it should be clear that the only way to make the Ju 88 perform like a P-38 would be a major redesign that would probably render it not suitable as a bomber with impressive internal capacity.
Had the follow-on designs to the Ju-88 focused more on just that sort of performance envelope with emphasis on minimal size/weight as well as drag (unlike the 188 and 288), then they might have had something considerably better to move forward with.Some radical surgery on the Ju 88 might have gottten similar reaults, but it would be a thinner wing, much better streamlining, and some very good attention to shape and details. The Germans never had a problem with attention to details and still don't. It probably could have been done, but the end result would also probably not be a Ju 88 as we know it. Rather, a different design with roots traced to the Ju 88 as an ancestor.
I don't really see the Ju 88 basic design as getting more than 15 - 20% better than it was with the engines and shape as it was.
Increasing weight in all those other areas could require structrual enhancement as well, though. Providing more provision for modification later on with that in might might have been more useful. (or high maximum fuel capacity AND more flexible/larger internal bombload, but not actually able to safely carry max bombs+max fuel at once)Don't stress the airframe for steep angle dive bombing, this may enable designers to add a proper internal bomb bay for 250 or 500 kg bombs and a fuselage fuel tank, maybe even larger capacity wing tanks. Some stressing should be done for shallow dive glide bombing to enable higher speed runs into target and away. Should also save some weight
Making those optional depending on mission profile would be good too. (as the Mosquito managed) But defending against frontal attacks and ability for ground strafing are significant, and those positions don't require added crew or excessive drag. (plus frontal attacks are more problematic psycologically, so having protection there -be it armor, guns, or both- would be useful, and speed or not, you can't outrun a head-on attack)Use a streamlined nose, bombardier may require large curved glass surfaces for visibility; multiple small glass panels may be cheaper but are aerodynamically inefficient. bombardier should have a trainable gun or pilot may have one or two fixed forward MGs on the fuselage sides or bottom.
Cockpit front with a larger single-piece glass with option to install armored glass.