How does the F4U-1A beat the Spit 16

[thorsim]

quite frankly considering the way the conversation started with specific aircraft i don't think i needed to state anything, it was always a practical discussion.

the theory was introduced by others who were trying to argue that weight and size have no real world consequences or effects in and of themselves.

i disagree.  

i did not try to run anything, i was just stating my case. i am sorry if you misunderstood.

t
  

Then you should have said "extra size and mass from the AIRFRAME cause engineering constraints such as extra control surface forces etc etc and these constraints will factor in as disadvantages to larger and heavier AIRFRAMES."

You have basically been trying to run a debate over the wrong topic the whole time.

[boomerlu]

Boomerlu I think what you're noticing is that thorsim isn't arguing any particular point, he's just arguing that he's right.

Meh, at least it wasn't a total waste of time. I figured out how roll rate works.

[thorsim]

hey look i am not rehashing old ground the 104 was not designed as an air superiority fighter and is a poor example because it is so extreme.

i offered the weight and power leveled f-16-f15 comparison but that was deemed not good enough ...

f86, mig 15 cant be used because of the control system differences spit and 109 not good because the wings and approaches to their design effect to much ...

some version hurricane and macci maybe,

or the same plane loaded and unloaded but power limited?

if you can think of a better example of a significantly bigger heaver but otherwise well matched pair of fighters i am all ears but i never said the other factors were not factors i just said weight and size are factors.

i am happy to look at a good example, and have stated so, so get upset elsewhere.  
  

Then you should have said "extra size and mass from the AIRFRAME cause engineering constraints such as extra control surface forces etc etc and these constraints will factor in as disadvantages to larger and heavier AIRFRAMES."

You have basically been trying to run a debate over the wrong topic the whole time. Your inability to come out with your point earlier is absolutely astounding.

Also note in the F104 vs F15 example, the engineering improved so dramatically for the F15 that it was able to overcome its inherent weakness of a larger and heavier airframe and is thus a better maneuvering fighter. Once again showing that a larger and heavier airframe alone will not make a worse fighter.

And finally, you only mentioned roll rate after 80% of the debate had already occurred despite repeated requests for you to completely define what you mean by maneuverability. Also, BnZ covered roll rate's non-correlation with mass.

[RTHolmes]

Wow, 12 pages later does anyone remember that this thread essentially started as a question on how the 1A can beat the Spixteen in a fight?

I believe the answer was "with equal pilots it cant", apart from maybe running it outta fuel


As you were.

[boomerlu]

There's no point to further discussion. We've resolved our differences, but you definitely should have stated more clearly your premise of discussion and stated it earlier. Basically everybody that argued with you has been going down a blind alley with regards to what you are talking about. We have argued entirely different things.

I doubt anybody would disagree that engineering practicalities caused by size and weight differences of the airframe would change performance and be biased towards lighter airframes. Note I say airframes because the weight of an "aircraft" implicitly includes all weight differences from engineering already.

Note also I said "biased towards". To what extent these differences would allow or prevent a particular bigger/heavier airframe from outperforming a particular lighter one can't be adequately examined without digging into a TON of technical detail in most cases. But an extreme case is the F104 vs F15 example I mentioned.

Also the reason we've been examining theoretical cases is simply because it is impossible to truly compare two different real aircraft in a way that accounts for (available lift)/weight, thrust/weight, and drag/weight. Essentially trying to argue this any way but theoretically with the scaling examples is comparing apples to oranges.

The closest you can get is the same airplane with a lighter fuel load. But a lighter fuel load improves all the above mentioned ratios. You can limit thrust so that thrust/weight is constant, but you cannot limit drag or available lift.

Anyways, that's my last word on the subject.

[Masherbrum]

Boomerlu I think what you're noticing is that thorsim isn't arguing any particular point, he's just arguing that he's right.

Someone else "get's it".

Have a seat and crack open a cold one from the Stryofoam cooler held together with ductape.   Ask Shuffler if he has an extra lawn chair.   

[thorsim]

i believe i asked for examples early on, and was not the only one involved in the discussion ...

could not someone just as easily have said, i know you can't do it practically but if you could ...

blame for the 12 pages should fall equally on them, don't you think?

There's no point to further discussion. We've resolved our differences, but you definitely should have stated more clearly your premise of discussion and stated it earlier. Basically everybody that argued with you has been going down a blind alley with regards to what you are talking about. We have argued entirely different things.

I doubt anybody would disagree that engineering practicalities caused by size and weight differences of the airframe would change performance and be biased towards lighter airframes. Note I say airframes because the weight of an "aircraft" implicitly includes all weight differences from engineering already.

Note also I said "biased towards". To what extent these differences would allow or prevent a particular bigger/heavier airframe from outperforming a particular lighter one can't be adequately examined without digging into a TON of technical detail in most cases. But an extreme case is the F104 vs F15 example I mentioned.

Also the reason we've been examining theoretical cases is simply because it is impossible to truly compare two different real aircraft in a way that accounts for (available lift)/weight, thrust/weight, and drag/weight. Essentially trying to argue this any way but theoretically with the scaling examples is comparing apples to oranges.

The closest you can get is the same airplane with a lighter fuel load. But a lighter fuel load improves all the above mentioned ratios. You can limit thrust so that thrust/weight is constant, but you cannot limit drag or available lift.

Anyways, that's my last word on the subject.

[hitech]

so the ability to speed up slow down and dive (unless you mean lift as a negative value as well) have no place in conversations about maneuverability?

 

yea we were posting at the same time.

well since the accepted limits on maneuverability in this discussion are limited to steady states of flight, and only one direction i will just leave all you experts at it and go into the arena and kill some more guys with my wild notions ...

+S+

t

so the ability to speed up slow down and dive (unless you mean lift as a negative value as well) have no place in conversations about maneuverability?

Per your definition of maneuverability they have nothing to do with it, YOUR definition was change in DIRECTION of the Vel Vector, speeding up or slowing down is changing it's length not its direction.


HiTech

[phatzo]

Someone else "get's it".

Have a seat and crack open a cold one from the Stryofoam cooler held together with ductape.   Ask Shuffler if he has an extra lawn chair.   

plenty of cold beer extra lawn chairs and a great view from the gold coast. Pull up a chair.

[thorsim]

actually that was bobs definition, mine was different and accounted for such changes ...

i think "bob" says something like

the ability to change the direction of your velocity vector ...

i would prefer the ability to change your state of motion ...

however, either will do.

remember?

Per your definition of maneuverability they have nothing to do with it, YOUR definition was change in DIRECTION of the Vel Vector, speeding up or slowing down is changing it's length not its direction.


HiTech

i know that may be nitpicking since i said either would do, but you did start it, and misquoted me again in the process ...

[Stoney]

I'm not sure why. But of course this is one front where my ability to reason from physics to aero ends.

Because determining thrust in a propellor aircraft is difficult, or perhaps imprecise would be a better descriptor.  To say that thrust is the same as     
F = M*A is not a good way to express it.  For example, a plane at zero velocity will still produce thrust, even though the equation would tell you otherwise.

But, I'm hijacking a bit.  Just use terms with caution...

[boomerlu]

F = M*A is not a good way to express it.  For example, a plane at zero velocity will still produce thrust, even though the equation would tell you otherwise.

But, I'm hijacking a bit.  Just use terms with caution...

Acceleration can be positive while velocity is zero . They're related but not equivalent.

I kind of see what you mean though. The conversion from horsepower to thrust is not exact because the propeller still has to cut air and it's not a 100% efficient transfer of force from the engine to the surrounding air - the turbulence caused by the prop reduces the efficiency.

Whereas a jet's thrust can be more easily measured by finding the output, I'm guessing? The output from a jet seems to be a more efficient transfer of engine power to usable thrust.

[BnZs]

EDIT : and since we are talking WW2 does the pilot have the strength to be able to deflect that much more force required to make the desired changes, if not how much will the system to assist the pilot weigh and once again you get into the scaling problem.

This is a valid point, however, as regards WWII prop fighters, it was apparently possible to design quite large fighters with decently light controls at typical WWII prop fighter airspeeds, if properly engineered. I can say this with confidence because the P-47 Thunderbolt, the largest single engine fighter of the war, had nicely light stick forces up to very high airspeeds, in fact lighter than those of many of its more miniscule contemporaries. And when you add powered control surfaces, this too becomes a non-issue.

[BnZs]

Also note in the F104 vs F15 example, the engineering improved so dramatically for the F15 that it was able to overcome its inherent weakness of a larger and heavier airframe and is thus a better maneuvering fighter. Once again showing that a larger and heavier airframe alone will not make a worse fighter.

As much as anything else, improved understanding of what fighters would be asked to and what attributes they needed to do it led to new designs like the F-15 and F-16. Initially jet fighters were haunted by the "dogfighting is obsolete, the planes go too fast and the weapon systems make it unnessecary" myth. Interesting, this myth was also widely held at the outset of WWII, before the lessons of actual combat once again taught people its falsehood.

[Masherbrum]

This is a valid point, however, as regards WWII prop fighters, it was apparently possible to design quite large fighters with decently light controls at typical WWII prop fighter airspeeds, if properly engineered. I can say this with confidence because the P-47 Thunderbolt, the largest single engine fighter of the war, had nicely light stick forces up to very high airspeeds, in fact lighter than those of many of its more miniscule contemporaries. And when you add powered control surfaces, this too becomes a non-issue.

Correct.   At my Kalamazoo AirZoo meet in Feb, they had an Open Cockpit weekend.   LyeEl sat in the D-40 they have, painted in and blessed by Gabreski's D-25 markings.  

The gentlemen posted on the Jug, flew Ponies and Jugs in WWII.   He preferred the Jug.   He said and I quote: "The biggest concern was "crabbing on the runway while taxiing.   But once the wheels lifted you could move the stick with two fingers, EASILY.   You cannot do that in a P-51 or most other fighters.   The controls were a dream to operate in the Jug and you had a ton of room as well."