Why didn't the Me 109 get a ventral radiator?
- Thread starter spicmart
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My guess would be something to do with the amount of room that the undercarriage mechanism and castings took up due to the outward folding undercarriage.
Shortround6
Major General
You have to be really careful comparing some of these things.
A lot of planes that used "underwing" radiators were actually using radiators part buried in the wing.
Spitfire radiator.
Hurricanes hung the entire radiator under the fuselage. Many of the planes you mention had a greater or lesser amount of the radiator inside the fuselage (above the bottom contour of the fuselage.
on the 109 you have an L shaped fuel tank that goes under the pilots and extends back an up behind the seat, you either stick the entire radiator outside the fuselage envelope or you push it back a few feet towards the tail which might not go well with the center of gravity.
"Underwing" radiators were used on a few pretty zippy airplanes.
Probably production issues. Ventral radiator also means relocating the drop tank facility to feature two tanks under wings now.
On the other hand, fully covered main wheel wells and return to retractable tailwheel will earn the same or better drag reduction while being easier to manufacture?
Me, I'd love to see the Bf 109 with annular radiator, like it was used on the Bf 209 (not the racer), but that will mess up the CoG unless tail is also lengthened like on the Fw 190D and later.
GregP
Major
The undercarriage takes up little to no belly room. It pivots on gear mounts that attach to the firewall.
But, the main fuel tank is in the belly just behind and below the pilot's seat. So, any belly radiator would necessarily be towards the rear a bit. There is no room at all forward of the fuel tank ... the floor is cockpit floor and that is right on top of the wing structure. Underwing radiators were no disadvantage, if well designed. The ones on the Bf 109 were. The oil cooler is not a factor at all. It is on the bottom of the cowling, below the engine mount, not on the fuselage.
But, the main fuel tank is in the belly just behind and below the pilot's seat. So, any belly radiator would necessarily be towards the rear a bit. There is no room at all forward of the fuel tank ... the floor is cockpit floor and that is right on top of the wing structure. Underwing radiators were no disadvantage, if well designed. The ones on the Bf 109 were. The oil cooler is not a factor at all. It is on the bottom of the cowling, below the engine mount, not on the fuselage.
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The 109f was tested with a ventral radiator. Here:
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQO0LucY8vYRZdV1PAITveDJqj9mPv_8ebMLzvrV1vtC6Ech5we
Obviously, it didn't make enough of a difference in performance.
It was also tested with tricycle landing gear. The 109 was a prisoner of Willy Messerschmitt's poor aerodynamics as well as the requirement of being able to out-climb opponents. Instead of balanced ailerons, it had horn aileron balances. Instead of hiding larger wheels and guns inside the fuselage and wings, it's small size required the addition of draggy bulges.
The only thing that would have improved the 109's drag co-efficient enough to matter would have been the laminar flow wing which was used in the 262 and P-51.
I'm a 109 fan. The hard-to-swallow truth is that it had too many faults to enable it to compete throughout the entire war.
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQO0LucY8vYRZdV1PAITveDJqj9mPv_8ebMLzvrV1vtC6Ech5we
Obviously, it didn't make enough of a difference in performance.
It was also tested with tricycle landing gear. The 109 was a prisoner of Willy Messerschmitt's poor aerodynamics as well as the requirement of being able to out-climb opponents. Instead of balanced ailerons, it had horn aileron balances. Instead of hiding larger wheels and guns inside the fuselage and wings, it's small size required the addition of draggy bulges.
The only thing that would have improved the 109's drag co-efficient enough to matter would have been the laminar flow wing which was used in the 262 and P-51.
I'm a 109 fan. The hard-to-swallow truth is that it had too many faults to enable it to compete throughout the entire war.
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- Thread starter
- #9
Why is the oilcooler a non-factor?
Chin-mounted coolers and radiators were quite draggy.
Just take the late Yak-models for example, which had it relocated from the chin to front edge of the wing roots. That was quite an improvement aerodynamically.
- Thread starter
- #10
It's surprising that many Messerschmitt planes seem to have mediocre/poor aerodynamics given the fact that he was known to have a clear focus on the performance of his plane and put less emphasis on their stability (weight).
Can you tell more?
The Bf 109 was a design from 1935, and for the standard of the day it was probably between top 3 aircraft with regard to streamlining. Much better in that regard than MS 405/406, I-16 or Hurricane.
Small size was a function of engines available (= tiny Jumo 210) and armament required (2 LMGs). That was able to 'swallow' the engine power increasing 3 fold during it's life, as well as major increase in firepower and carrying capacity is a testament of it's viability and longeivity.
That nobody saw fit to install belt-fed MG FFM on the wings of the Bf 109 (and thus remove HMGs from fuselage) was no fault of the design; Spanish installed the big Hispano 404 in the wing of their version.
Speed gain was easy to achieve via retaining the reatractable tailwheel from the 109Fs and 109G-2s, while installing wheel well covers ASAP, not wait until the 109K series.
GregP
Major
Hi Spicemart,
The oil cooler is a non-factor because it is not on the fuselage. You originally asked about ventral radiators, not chin-mounted radiators.
The Bf 109 not only competed against the best for the entire war, but traded the title of "best fighter" back and forth with the Spitfire and sometimes the Fw 190. At the end of the war, had anyone run across Erich Hartmann (or any number of other guys) in his Bf 109, and had they regarded him lightly, they'd likely have been a victim, not a victor, even one-on-one. The Bf 109 was a very GOOD fighter that somehow never had it's major faults corrected. It would have been easy to add a decent windscreen, add rudder trim, and change to inward-retracting gear. It also should not have been that hard to change to a different airfoil, had Willy wanted to make that change. It's as easy to rivet to a new rib as it is to rivet to an existing rib. And the main fault that SHOULD have been corrected in any case is the very short range. Even another 30 minutes would have been useful on missions over the UK. As it was, the Bf 109 pilot on a mission to the UK had only 10- 15 minutes of time there.
The Bf 109 was also hardly ever not fast enough and it usually had no trouble outclimbing the opposition. Top speed is not much of a factor in combat or cruise to combat, according to WWII pilots I have spoken with. While some in here seem to believe it is the most important element, the guys who were there didn't. I've asked some 45+ WWII fighter pilots about it. The combat speed was important, and that would be whatever speed you could achieve when going from cruise to combat with something like 30 seconds to accelerate from cruise to whatever speed you were going when you joined combat. It was largely around 300 - 325 mph, and then you had more important things on your mind than airspeed. Flying straight and level while accelerating also wasn't much of a survival tactic. Most WWII dogfights were a downhill affair, and the speed could get higher as you went down, but the important thing was to get your opponent in front of you, not to outrun him ... unless you were the one running. THEN speed was vital and offered the ability to break off combat. But that speed was very short-lived. I doubt there were many 20-minute tail chases. If you did that, you lost your squadron and likely your own wingman and you found yourself with an overheated engine in a sky all alone except for the target disappearing in front of you. That was not a good place to be.
The oil cooler is a non-factor because it is not on the fuselage. You originally asked about ventral radiators, not chin-mounted radiators.
The Bf 109 not only competed against the best for the entire war, but traded the title of "best fighter" back and forth with the Spitfire and sometimes the Fw 190. At the end of the war, had anyone run across Erich Hartmann (or any number of other guys) in his Bf 109, and had they regarded him lightly, they'd likely have been a victim, not a victor, even one-on-one. The Bf 109 was a very GOOD fighter that somehow never had it's major faults corrected. It would have been easy to add a decent windscreen, add rudder trim, and change to inward-retracting gear. It also should not have been that hard to change to a different airfoil, had Willy wanted to make that change. It's as easy to rivet to a new rib as it is to rivet to an existing rib. And the main fault that SHOULD have been corrected in any case is the very short range. Even another 30 minutes would have been useful on missions over the UK. As it was, the Bf 109 pilot on a mission to the UK had only 10- 15 minutes of time there.
The Bf 109 was also hardly ever not fast enough and it usually had no trouble outclimbing the opposition. Top speed is not much of a factor in combat or cruise to combat, according to WWII pilots I have spoken with. While some in here seem to believe it is the most important element, the guys who were there didn't. I've asked some 45+ WWII fighter pilots about it. The combat speed was important, and that would be whatever speed you could achieve when going from cruise to combat with something like 30 seconds to accelerate from cruise to whatever speed you were going when you joined combat. It was largely around 300 - 325 mph, and then you had more important things on your mind than airspeed. Flying straight and level while accelerating also wasn't much of a survival tactic. Most WWII dogfights were a downhill affair, and the speed could get higher as you went down, but the important thing was to get your opponent in front of you, not to outrun him ... unless you were the one running. THEN speed was vital and offered the ability to break off combat. But that speed was very short-lived. I doubt there were many 20-minute tail chases. If you did that, you lost your squadron and likely your own wingman and you found yourself with an overheated engine in a sky all alone except for the target disappearing in front of you. That was not a good place to be.
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Dr. Messerchmitt seemed reluctant to redesigning his planes (and german planning not wanting to lower any production output due to changes), apart from the flying bump-fest of the Me109G, how hard would it have been to stretch out the wing or fuselage a bit to let Me110 night fighters carry a bit more internal fuel rather than the drop tanks they were forced to carry.
I think this is the speed range where the 109 excelled and explains why it was a good fighter with ace pilots until 1945, the 109 wasn't a good low speed turner and not the greatest at high speed handling, but it had good power/weight acceleration and climb and its average aerodynamics were not to draggy at 300mph speeds where actual combats mostly occured at.
I think this is the speed range where the 109 excelled and explains why it was a good fighter with ace pilots until 1945, the 109 wasn't a good low speed turner and not the greatest at high speed handling, but it had good power/weight acceleration and climb and its average aerodynamics were not to draggy at 300mph speeds where actual combats mostly occured at.
Admiral Beez
Major
Second only to surface radiators and leading edge radiators, I would think the dorsal radiator would be the least draggy of them all, since the top airflow is already distrupted by the cockpit, and the bottom is smooth.
Ugly as heck though......
GregP
Major
The Sud-Est 580 never flew, but the design is solid WWII. Cancelled in 1947 as I recall. So, you have to put the radiator SOMEWHERE for a liquid-cooled piston engine, and we have seen it all the places where it could go ... chin, belly, ventral (behind the wing on the belly, on the sides of the fuselage, wing leading edges and now, on to behind the cockpit. There are not a lot of other places, aside from tail inlets, where you might mount the radiator. I believe the Bugatti racer had tail inlets.
Redirect Notice
Redirect Notice
wuzak
Captain
The ventral radiator isn't automatically better.
I doubt that the Hurricane's ventral radiator was any better than the Spitfire's wing radiator.
The ventral radiator on the P-40 prototype worked so well they moved it to under the nose after the first few flights. Similarly for the Hawker Tornado prototype, the chin radiator being carried forward to the Typhoon.
There was a proposal for a ventral radiator for the Spitfire, but the need for continued production trumped any improvements that may have been made.
I doubt that the Hurricane's ventral radiator was any better than the Spitfire's wing radiator.
The ventral radiator on the P-40 prototype worked so well they moved it to under the nose after the first few flights. Similarly for the Hawker Tornado prototype, the chin radiator being carried forward to the Typhoon.
There was a proposal for a ventral radiator for the Spitfire, but the need for continued production trumped any improvements that may have been made.
Not all ventral radiators were the same. There were layouts of 'let's stick them in the airstream' types (Hurricane, possibly Ki-60, indeed prototype Typhoon and XP-40), then semi-burried types (Italian & Soviet fighters, Ki-61, probably D.520) that were better, and then semi-burried types with boundary layer splitter (P-51 went with at least 4 iterations, MB.5 prototype, claimed also the late D.520 modified during the Vichy France) that were the best.
swampyankee
Chief Master Sergeant
- 3,986
- Jun 25, 2013
Ideally, you want the radiator duct's inlet in a high pressure area and the exhaust in a low pressure area. The airflow should also be clean. It then gets slowed down in a diffuser, passes through the radiator core (where it will get hotter and lose total pressure), thence to a nozzle and the exhaust. If you are both good and lucky the exhaust velocity will be greater than the inlet velocity. Usually, you won't.
Otto_+
Recruit
Are talking about a ventral radiator like Bf-109 C ??
This radiator was discarded due to big drag obtained, despite of that hot air expelled generated a sustanciable trust.
but the separate under-wing configuration show better performance, with less drag and enough hot air trust, due to so called Meredith effect
Or you refer to Bf-109 V31 prototype??
This was a retractable radiator experiment used in Me-309 later.
