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I think you're confusing models -The Oscar 1 wasnt that slow!! it had the same max speed like the Zero 2.
Agree to a point - I have to look up my references as to the P-40B/C sea level speedsSo Sea level speed was around 460km/h vs 475km/h of the P40C.
As higher the planes did fly as better the Ki-43-1 got, in comparison to the P40C. Due to the higher weight, smaler drag and higher engine power, the P40C always could outaccelerate the Oscar1, same like the Zero 2 in a shallow dive, while the initial acceleration was way better with the Japanese planes.
And they usually "sped away" in a dive which gave them way more than 20 mph. The Zero's VNE was 410 mph from what I remember. The P-40 was able to safely dive at speed in excess of 480 mph.Since the allied pilots fast got aware of this, they just kept the speed up and avoided tight fights and they was happy not to have a 20mph slower airplane.
The Oscar 1 wasnt that slow!! it had the same max speed like the Zero 2.
So Sea level speed was around 460km/h vs 475km/h of the P40C.
As higher the planes did fly as better the Ki-43-1 got, in comparison to the P40C. Due to the higher weight, smaler drag and higher engine power, the P40C always could outaccelerate the Oscar1, same like the Zero 2 in a shallow dive, while the initial acceleration was way better with the Japanese planes.
Since the allied pilots fast got aware of this, they just kept the speed up and avoided tight fights and they was happy not to have a 20mph slower airplane.
Thirdly maximum level speed is a funny thing. It is like the disparity between service ceiling and operational ceiling. Assuming you have not overloaded the airframe and can use the same angle of attack between weight changes, the maximum level speed is never affected by weight alone but and this is a very important but, if you make an aircraft heavier the time it takes to accelerate to your maximum level speed maybe too long to make it usable in service conditions.
The only thing which limits maximum level speed is thrust to drag, not weight.
So if you get a Spit, which can do say 360mph and then you make it heavier without increasing drag,
No. The reason it does 350 mph is because the engine thrust cannot overcome the added drag of the lift needed to carry the added weight.the only reason it now does 350mph is because it takes too long to continue accelerating to 360mph under service conditions. By that I mean it works like this...
Feller, that's how it works.
Here are a few comments, first the impact of top speed. In my mind top speed has two important components to combat, engaging and disengaging. Once maneuvering combat starts, top speed become irrelevant except for disengagement. Other factors become more important including turn rates, sustained turns, acceleration, climb rate, dive rates, etc. However, I believe that an actual 20 mph, not tested, not calculated, etc., is indeed a significant amount of airspeed advantage. A fighter, with a 20 mph overtake, one mile behind another fighter, will catch the chased fighter in three minutes. In addition, this speed advantage would help significantly to withdraw, say, when you run out of ammunition. As I have stated before, if you are on the highway at 70 mph and someone passes you at 90 mph, you would say "boy, that guys in a hurry". If I remember my T-38 days correctly, if one was to perform a formation rejoin with a 20 mph closure, he would find himself either wings level zooming under lead for a turning rejoin, or, throttles idle, speed brakes out, swapping leads in an in-trail rejoin (been there, done that). In either case, he would find himself being "politely" chewed out from one end to the other by the instructor in lead.
Now, for any two given aircraft, this 20 mph advantage is extremely hard to determine without side by side testing due to the variables previously discussed.
Great post Dave - one also has to consider that during in that 3 minute chase you're probably at full power which in most aircraft would be limited for 5 minutes. Bump that scenerio to 2 or 3 miles and more than likely you're not going to be able to chase down the other aircraft without doing some damage to the engine.
As far as that 20 mph for disengagement - put 2 aircraft wintip to wingtip and one tries to disengage with that 20 mph advantage. Unless he can quickly accelerate to exploit that speed advantage, he's just setting him self up as a nice jucy target, that's the point I'm trying to make.
LOL - I can agree with that!You certainly cannot outrun a bullet so you would have to have separation before you dashed off. Still better than being 20 mph slower!
BINGO!It is interesting discussing what makes a great fighter, speed, climb, acceleration, armor, armament, etc etc. Every pilot says his plane is the best, but then he represents the ones that lived. The pilots that were killed never complain about their aircraft. And the pilot is a major part of the weapons system. Each aircraft has its on set of characteristics, the better ones had more better characteristics than the poorer ones. Expert pilots could utilize the good or avoid the bad characteristics of their aircraft to achieve advantages over the less expert pilots. The arguments will go on ad infinitum.
Knegel as I understand it you've been talking about Vmo, not Vmax and we both seem to agree you're not talking about VNE or critical mach.
You seem to be missing the most basic description of the four primary aeronautical forces of lift, weight, thrust and drag and the secondary rule to get more lift, just go faster.
Here it is again. So long as you've maintained correct airframe balance installing your extra weight, being heavier doesn't mean you have to raise AoA.
You be wrong here and what please is "normal speed"??You don't have to start pointing the nose up just because you raised wing loading. The 109G actually has less wing area than the Emil and more weight, but flies at the same AoA at normal speeds.
Drag is not increased when increasing loaded weight, so long as the airframe remains properly balanced and this weight isn't in external protrusions. Stall speeds increase though, so at very low speed you have to raise AoA or put your flaps down sooner, or land faster. It's only at low speeds.
The only time this isn't true is if you've exceeded the maximum wing loading on that airframe design by increasing weight too much for the wing area that you have.
The Messerschmitt has a higher wing loading than the Spit, and it doesn't run around at a higher AoA than the Spit. They both sit at something like 3-deg at cruise and neutral in the high speed condition (handled with elevator trim).
Everything I wrote about thrust, drag, torque and weight is physically sound.
I won't go venture into speed testing conventions and benchmarks as it would be a long conversation which would hijack the thread too much and isn't directly relevant to the point anymore than you said Vmax wasn't. I'm sure we both understand conventions vary between RAF, NACA and USN testing procedures, and then again by the time period (it's a hilarious story how they tested design limitations in the thirties, I'm surprised any test pilots survived, I mean seriously 12g pullouts at 5000 feet in an F3F those Navy guys were insane).
To increase the lift, you need to increase the angle of attack and this increase the drag and this decrease the speed.
As such "more weight = less speed", while the engine power and altitude stay the same, is absolut correct.
And yet this is simply not true. If your weight increases enough to have to raise the AoA (a factor of wing loading at a given airspeed), then all you have to do is fly faster to bring the AoA back down again.
Here is what you guys are talking about, economy cruise is roughly speaking the minimum speed the aircraft can do without having to have too high AoA to cause fuel burning drag. If you go slower than your economy cruise, then you get close enough to the stall speed to have to raise AoA and you would actually have to use more power to keep the lower speed. You would use more fuel going slower than you would going slightly faster, because of AoA-induced drag at the slower speed. So the economy cruise setting is a compromise between not too much AoA and as little excess thrust as possible.
Hope you can follow me here.
Let's say our economy cruise is 300km/h at 7-deg Alpha. My stall speed is 270km/h at 30-deg Alpha. To go at 280km/h and 25-Alpha just above the stall speed I would actually use more fuel than I would at 300km/h because of the increase in drag.
Bear with me.
Now I make my plane heavier. My stall speed is now 280km/h at 30-Alpha. If I wanted to do my normal economy cruise at 300km/h I would be at 10-Alpha. OMG you're right I have to raise my AoA because I made the aircraft heavier.
NO WAIT, hang on a minute! I can just increase my economy cruise to 310km/h and I will be back at 7-Alpha.
But because my engine is working a little bit harder I will use a little more fuel in economy cruise when I'm heavier. And I will have to go a little bit faster to maintain the original AoA.
Here's the key point: you guys are talking about maximum level speeds which are well and truly above the stall speeds until you get near the service ceiling. By a lot. Tons of room to play with to keep AoA commonality unless you go absolutely stupid with overloading the plane with extra weight.
I rest my case.
(concluding with my very first point, two examples of the same aircraft, one heavier will have the same Vmax but different maximum level speeds under service conditions. heavier aircraft may run out of fuel before they can reach their previouis maximum level speed when lightened, because you accelerate harder for longer lighter, an inertia thing or that force which resists acceleration, a function of mass).
I don't quite understand what you're trying to say but I think you're saying that in a close-in encounter, maximum speed is not that important. If so that's been my point from the beginning and I believe that's wahy davparlr eluded to.As i wrote many times here, maximum speed is not all, but for a less good turning and climb plane its all and everything(P40 vs Zero).
If the P40 would have been 20moh slower, its dive acceleration wouldnt have been as good as well.
Great, and how do you want to do that at Vmax level speed, where you already use max engine power??
For a given plane at a certain weight the following apply.You're just not getting it. You don't need to go faster at the maximum speed because you're far enough above the stall speeds of the aircraft that you will not have to raise AoA when making it a little bit heavier.
You raise the AoA when your airspeed is getting close to the stall speed.
Let me say that again. You raise AoA when your airspeed is getting close to the stall speed.
But if the weight is internal, drag not being an issue from installation of weight itself, your maximum speed and even maximum cruise are going to be high enough above your stall speeds that you just won't have to raise your AoA for level flight. The reduction in top speed is because acceleration and service use, it is not a reflection of Vmax for the airframe (again why I stipulated you were using the Vmax terminology incorrectly).
I don't quite understand what you're trying to say but I think you're saying that in a close-in encounter, maximum speed is not that important. If so that's been my point from the beginning and I believe that's wahy davparlr eluded to.
Remember what was said here - SEPERATION. That 20 mph advantage will work for a fleeing aircraft if there is enough separation to keep his opponent at bay, keeping clear of any firing solution his pursuer may try to establish. But as stated, if you're trying to run in an aircraft with a 20 mph speed advantage over your opponent and don't have the separation, no WW2 aircraft is going to outrun a bullet.
That's the same for ANY aircraft - S/L speed will be lower but the airframe and engine will perform better mainly in climb performance (Vx and Vy)Hi,
all iam saying is that 20mph more maximum level speed is not "pissing against the wind", like someone told.
A 109E with a real maximum speed of 550km/h at height and 450km/h sea level is a different plane than a 109E with 570km/h at hight and 470km/h sea level and thats just 20km/h not mph!!
Not always true - you have yet to bring up power to weight ratio for a given aircraft.For the generally same airframe, even if i dont know what is the cause for 20mph more or less, i can safely assume that the faster plane also will accelerate better, zoom up better and also dive faster. Depending to why the plane is faster(less drag or more power) i also can estimate that the plane climb better(more power) or accelerate better in a high speed dive(less drag).
And do you have performance charts to back up that claim?20mph more or less maximum level speed have a impact to the whole flight performence.
You can have a 109E with 450km/h sea level but the same accleration like a 109E with 470km/h sea level.
If the speed difference is related to more power, also the climb and turn performence will change extrem!
And that only with 20km/h, not mph.
20km/h in case of the 109E is equal to around 50PS more or less, in this case thats 5% engine power, 20mph would be more. Thats not pissing against the wind.
Greetings,
Knegel
Sure thats the same for any aircraftThat's the same for ANY aircraft - S/L speed will be lower but the airframe and engine will perform better mainly in climb performance (Vx and Vy)
Sure thats always true. An example is the 109E-4 vs the 109E-4/N or 109E-4/N vs the 109F.Not always true - you have yet to bring up power to weight ratio for a given aircraft.
Climb out of high speed."zoom up better?" You man climb?
And if the P40B would have been 20mph slower, it would look like this:Go back to the P-40
Was it able to out turn a Zero or Oscar? NO
Was it able to outclimb either aircraft? NO
Was it able to out accelerate either aircraft? Depending on altitude airspeed
Was it able to outdive a Zero or Oscar - YES
There is a typo, i actually meant "You cant have a 109E with 450km/h sea level but the same accleration like a 109E with 470km/h sea level. "And do you have performance charts to back up that claim?
If the aircraft is trying to run with no SEPERATION to exploit that 20 MPH advantage, it is pissing in the wind, and that's been the point from the beginning.
Explanations have been clear. You cannot carry weight for free. You prove that every time they weigh your baggage when you get on an airliner. More weight, more lift required, high AoA for given airspeed, more induced drag, higher throttle setting to increase thrust to offset higher drag, more fuel used. If you add weight to a fighter at top speed no more thrust is available to offset the increased induced drag, fighter MUST slow down or pick up a descent rate.
Where did you come up with your position on weight and airspeed?