How does the F4U-1A beat the Spit 16

[BnZs]

Mntman:
Nope. Neither size nor weight alone tell us anything about the rate or radius of turn for a given aircraft.

Seriously?  You want to argue along those lines?  Looks?  What's next?  FW190 should fly like an aerobatic plane, cause it looks like one?

Compare a modern, high-performance specialty plane against a 70 year old warplane?  Design differences, materials, weights, are nothing alike...  Airfoil differences alone...  Fixed gear, no flaps...  Sheesh, not even close to an apples/apples comparison!

I'm with you on the size idea, BTW. 

BNZ has been careful to keep his argument to thrust/weight/lift, without including overall size.  Making a copy of a plane ten times larger (or smaller) would greatly change it's measured turn radius.  But he's not saying 10 times larger.  He's saying 10 times heavier, more thrust, more lift; overall size stays the same.  I'd tend to agree with his argument there...

And what's the overall point you're trying to make here?  Are you of the opinion that the F4U out-turns the spit16 in AH?

[mtnman]

Mntman:
Nope. Neither size nor weight alone tell us anything about the rate or radius of turn for a given aircraft.

Well, they tell you something...  Just not enough for either one to tell the whole story alone...

An argument based solely on one variable would be pointless, yes.  I'm also questioning how far the "theory" could be taken in reality. 

For example, take a full-size P51, and create a same-sized copy of it 10x heavier, 10x more thrust, and 10x more lift.  How could you do that, and even consider it a "copy"?  If the airfoil stays the same, how can it ever generate 10x more lift without an increase in flying speed?  If the speed increases, it can't really be considered to be flying the "same way", and I'd be awful skeptical that it could have a comparable turn radius.  Rate?  Maybe, cause it'd have to be haulin' donut to stay in the air...

Likewise with size- if you made a "copy" 10x larger (370 ft wingspan), I would in expect it in reality to be much more than 10 times heavier.  I realize that could be compensated for with different building materials, but when I fly my birds, one that's twice as large as another weighs roughly 8x as much as the bird it's twice as big as.  Overall size doubled, weight goes up at a much faster rate.  Same thing with my lead balls for my rifles.  Double the size, weight increases by @ 8x.  Regardless, how would we test it?  Fly it at the same speed as the smaller model?  Or would that be adjusted for scale too?  If it flew at the same speed, it would look like it was floating in comparison.  Fly it at a "scale" speed, and I'd expect the larger version to take a longer flight path around the circle.

Things get kind of messy in my mind when we start to radically adjust scale.

[BnZs]

you need to look into that test, it is too flawed to be seriously considered. as far as the USNs opinion of the 190 the design principals used for the F8F is a better example than that test of the bomber fighter to which you refer.

The aspects of the Fw-190 that *might* have figured into the design of the F8F were its power/weight ratio and aileron design. Giving the F8F a relatively high wingloading like the 190's would not have done anything for its maneuverability. All 190 variants were significantly heavier loaded than the HellKitty/Corsair, and there is 0 debate among the non-delusional about the 190's deficiencies as a turner.

the p51 was not considered a great turner ...

At altitude, it was a decently competitive turner against the 190s and the late 109Gs it fought. Especially the 190s. This is born out by both the physics and pilot reports. It is still a decidedly poorer turner than the F4Us...or do you wish to now claim the Corsair should turn worse than the P-51 because it is larger?

going to such extremes as the mig 17, i think the 20 years and a few other things would preclude those two planes as a good example, however yes the mig 17 was considered an excellent maneuver fighter vs. it's BIGGER HEAVIER contemporaries, thanks for the excellent example of my point.  

The Mig17 out-turned the F4 because the latter's wing loading was basically twice as heavy. The F4 still out-climbed and out-accelerated the Mig, because its ratio of thrust/weight was higher.

spits after the 5 when they had to contend with the later axis aircraft by sacrificing some maneuverability for more power.

Yes, sticking a larger engine in the same basic airframe will result in a higher wingloading. What is your point?

no i get that what you fail to "get" is that size and weight itself is a factor above and beyond what they do for the loading values, as is power.

once again i refer you to acrobatic aircraft and why they look a lot more like a small fw190 than a small p38.

No, it really isn't it, as far as basic performance is concerned.

They look like a small fw190 because why would you go to the trouble and cost of constructing a twin-engine, twin-boom aircraft for such a purpose? And also because roll rate is an important part of aerobatics, the 190's planform (most of the weight close to the center axis, relatively low aspect ratio wing) IS beneficial to roll rate. This of course has nothing to do with the high wingloading that made the 190 a relatively poor turner, which would of course be unacceptable in an aerobatic aircraft.

once again i refer you to newton,

What part of the good Sir Isaac are you referring to?

and even though the numbers you quote below may give a very close match up in stable situations the maneuver fight is won in the transitions between those more stable situations, and the smaller lighter quicker aircraft wins those fights.  

Nonsensical gibberish.

[BnZs]

You  have a point with the scaling concern, but that does not change the fact that is possible for larger aircraft to have equal/better lift loadings and power loadings than smaller ones and that this will lead to equal/better turn, climb, and accel performance, all other factors being equal.

IF you can get two aircraft to sustain the same speed, G, and bank angle, rate and radius will be identical. It really doesn't matter if one aircraft is a small R/C model and the other is an airliner.

Well, they tell you something...  Just not enough for either one to tell the whole story alone...

An argument based solely on one variable would be pointless, yes.  I'm also questioning how far the "theory" could be taken in reality. 

For example, take a full-size P51, and create a same-sized copy of it 10x heavier, 10x more thrust, and 10x more lift.  How could you do that, and even consider it a "copy"?  If the airfoil stays the same, how can it ever generate 10x more lift without an increase in flying speed?  If the speed increases, it can't really be considered to be flying the "same way", and I'd be awful skeptical that it could have a comparable turn radius.  Rate?  Maybe, cause it'd have to be haulin' donut to stay in the air...

Likewise with size- if you made a "copy" 10x larger (370 ft wingspan), I would in expect it in reality to be much more than 10 times heavier.  I realize that could be compensated for with different building materials, but when I fly my birds, one that's twice as large as another weighs roughly 8x as much as the bird it's twice as big as.  Overall size doubled, weight goes up at a much faster rate.  Same thing with my lead balls for my rifles.  Double the size, weight increases by @ 8x.  Regardless, how would we test it?  Fly it at the same speed as the smaller model?  Or would that be adjusted for scale too?  If it flew at the same speed, it would look like it was floating in comparison.  Fly it at a "scale" speed, and I'd expect the larger version to take a longer flight path around the circle.

Things get kind of messy in my mind when we start to radically adjust scale.

[thorsim]

since the hog is @ 2x the weight yet not nearly 2x the size of the spit it can not hope to get enough air resistance to change the direction of it's velocity vector as quickly as the spitfire 16.

i will leave it at that i think.

[mtnman]

oh and as far as your agreement with b and z then the hog 4 should by your logic should outmaneuver the hog 1 likewise the 190 a8 should outmaneuver the a5, is that the argument you are trying to make?

I don't know anything about the 190's; I'm not even sure if I've ever flown those models.

Outmaneuver, yes, I'd expect so, although I wouldn't necessarily expect it to out-turn it.  

Since we're talking nearly identical planes with a stronger, heavier engine in one, I sure wouldn't expect the plane with the lighter, weaker engine to be the better performer.  Would lowering the weight and power of the -1 engine have made the -1 fly better?  Of course, I think there's a point where the engine could be too heavy, and too powerful to be beneficial.

Mainly, the lower thrust of the lower-class plane can't maintain energy to maneuver with the ease that the higher powered version can.  The lower powered plane may very well be able to turn tighter than the higher powered version, but that's not enough to really matter in the end.  It'll run out of E sooner, and succumb to the higher powered version.

Our fight results are not dictated by results of one maneuver, but rather by successive strings of maneuvers.  Can the lower powered plane win the fights?  Absolutely!  But it comes down to the pilot there, not the plane.

If it was just a matter of "this plane trumps that plane" we could just make the fight results more like a game of rock, paper, scissors.  You fly along in your 190, until you see a P51, at which point you die.  Why fight, if one plane is better?

[mtnman]

You  have a point with the scaling concern, but that does not change the fact that is possible for larger aircraft to have equal/better lift loadings and power loadings than smaller ones and that this will lead to equal/better turn, climb, and accel performance, all other factors being equal.

IF you can get two aircraft to sustain the same speed, G, and bank angle, rate and radius will be identical. It really doesn't matter if one aircraft is a small R/C model and the other is an airliner.

Yup, I agree there...

[mtnman]

since the hog is @ 2x the weight yet not nearly 2x the size of the spit it can not hope to get enough air resistance to change the direction of it's velocity vector as quickly as the spitfire 16.

i will leave it at that i think.

So, we're at "size and weight matters, but nothing else does"?  What about thrust, lift, shape, drag, et al...

That could sure lead people to make erroneous judgments.

[thorsim]

no you are projecting again, my point is that everything matters, including size and weight beyond their effects on the loadings.  size and weight matter just as much as anything else, on their own.

So, we're at "size and weight matters, but nothing else does"?  What about thrust, lift, shape, drag, et al...

That could sure lead people to make erroneous judgments.

[hitech]

Likewise with size- if you made a "copy" 10x larger (370 ft wingspan)

Mtnman i would say 10x larger , means 10x the wing area not 10 times the wing span for this discussion.

And over all I am on BNZ side of this discussion .(concept wise, not the specific f4u1 and spit16, for that discussion no one here has begun to give enough details to make a real choice) He is just not describing every little piece of the discussion.

But the one item that is missed here when you scale a plane up is roll rate, yes given the concept of 10 times area,weight and power, turn rates , stall speeds, turn radius , and climb rates would all be the same so thorsim argument is either badly described or does not hold water.  As to who has the minimum turn radius, just compare stall speeds of the 2 planes.

What is strange is that the numbers can be tested very quickly in game, yet you guys sit here arguing which is best with out spending 20 mins running some tests in game.

HiTech

[boomerlu]

Actually I'm starting to see Thorsim's point.

Drag is NOT a function of mass, whether it is parasitic or lift induced (lift induced being the one we're interested in here).

Drag is a force, the energy lost due to drag is the line integral Integral[Drag * ds]. Notably, this equation does not involve aircraft mass. On the other hand, kinetic energy is KE = m v^2, which DOES involve mass.

Assume we're analyzing two aircraft, one with twice the mass but the same wing area as the second.

Now, the aircraft with twice the mass will require twice the lift to pull the same turn. As per the equation for lift-induced drag
D~L^2/S (where L is the lift and S is the wing area)
any amount of lift will induce a drag proportional to the square of the lift , therefore the aircraft with twice the mass (and twice the lift to pull the same turn) will incur FOUR times the drag to pull the same turn since the wing area is the same. Correspondingly, it will dump FOUR times the energy in the same turn as the energy lost is linear in the amount of lift.

But the aircraft with twice the mass only has twice the energy (given equal velocities) as per the kinetic energy equation. So an aircraft with more mass but the same wing area will bleed a proportionately larger amount of energy to pull the same turn.

Here's HiTech's and BnZ's point:

Notice again the equation for lift induced drag has proportionality:
D ~ L^2/S
If we increase the wing area by the same factor as the mass (and therefore by the same factor as the lift), we see that drag increases linearly with mass. This means that an aircraft with 2x mass but 2x wing area will bleed proportionately the same amount of energy in a turn as one with 1x mass and 1x wing area.

This reinforces HiTech's point, if we scale the ENTIRE plane's statistics, we'll come up with the same turn performance.

[boomerlu]

I'm not sure on the following, but I believe you cannot scale a plane's performance by simply making every dimension of the plane larger (even if we handwave and say that the engine produces 2x more horsepower with 2x more weight).

This is because mass is proportional to volume, which is proportional to (dimensions of the plane)^3. On the other hand, planform and wing area (which are very important in calculating lift etc) scale as (dimensions of the plane)^2.

Roll rate... wouldn't roll rate scale properly if we increased wing area and mass equally? The assumption being that we also scale the size of the ailerons, so they'd provide proportionally more torque to overcome the wing area's resistance to rolling (which I believe is linearly proportional to wing area).

Edit: sorry to pull out the formulas and everything, but how else can a person understand WHY scaling something up won't work? Without the formulas, you're reduced to trusting whoever seems to know what they're saying the best.

[Noah17]

Wow, there's all kind of stuff I hadn't thought of...
Didn't mean to get people all stirred up....Kind of liking it though.
Learnin lots!

 

Yes...Actually used the dancing banana.

[thorsim]

the less you have to move around the less energy it takes to move it and the more energy you will retain while doing  so ...

due to the physical and engineering limitations it is more likely that you will achieve superior maneuverability by reducing size and weight than you would trying to increase the size and corresponding power of your aircraft.

i suspect that you will find that all the designers make the smallest lightest aircraft they could which would meet the requirements of it's design purpose.

increasing power adds weight, increasing wing area adds weight.  things are not as simple as oh well i will just double my wing area and double my lift loading.

an aircraft is "a series of compromises flying in close formation" the fewer concessions to requirements not directly related to air combat the better pure fighter you can make. 

it may not be able to land on a carrier, or fly for eight hours, or have a redundant power plant, however it would likely out perform any of those planes that could do those things for the simple reason that the design was not compromised to be able to do those things.

t

[Saxman]

One thing about the Corsair is that the wing configuration introduces a number of odd wrinkles. Would it necessarily explain everything? Maybe not, but the way the wings are angled at the roots was discovered to greatly reduce drag on the airframe. The wing is also larger than it looks (straighten out the wings and she's sure to gain a good bit of span on each side) and certainly has a particularly broad chord all the way out towards the tips. The lowest point of the wing is also positioned in a way that places it well BELOW the fuselage (I think the top wing surface ends up in line with the very bottom of the fuselage).

Has there ever been an actual targeted study of the aerodynamic effects of the Corsair's wing configuration?