You're kidding, right? Based on seeing some 'video', you think the F-35 seems a little 'heavy'? Heavy compared to what? A 747 seems 'heavy' to me - it still does the job it was designed for.

First of all, the weight (mass) distribution 'from the centerline' (the mass moment of inertia in the roll axis) has next to nothing to do with 'turn' capability. It directly affects roll rate capability, yes, so it has an effect on how quickly you can bank into a turn - but the actual turn capability (the ability to 'change the direction of forward motion') is a function of lift and weight, (and drag and thrust, if you are talking about sustained turn capability). Even so, you cannot tell how much roll capability an aircraft has by looking at it. You don't really know the mass distribution, and you certainly don't know the aerodynamic effectiveness of the control surfaces, and you have no clue as the the aerodynamic roll damping (maybe your high school physics class was way more advanced than mine).
So, will the F-35 match the F-16 (for example) in terms of maximum roll rate? No. Does it need to? No. Dirty little secret here - those insanely high roll rates that the F-16 can generate are pretty much limited to moderate/high speeds at low load factors (i.e. low AOA). Is there anything more tactically useless than a really quick 360 roll at 1g? The simple fact is in the parts of the sky where roll capability really is tactically useful (slower speeds and/or high load factors (i.e. elevated AOAs)), for instance high-g reversing (scissors) - the F-35 will far exceed the F-16 capability.

Ok, so you got the point about weight distribution and turnability of an airplane. It seems that every time I want to make a turn in a Piper that the first thing I do is initiate a roll to one direction or another. Never seen an airplane change heading by rotating about its center of mass either counter-or-clockwise. Roll rates directly affect "turnability" of a winged airplane.

And while I, or any outside observer, may not know the *exact* weight distribution, its easy enough for a farm-boy-engineer to look at the F-35 and look at the landing gear location, the gun location, the hydraulics for the gear and weapons bay doors, and the weapons ejection hardware, not to mention the internal structure needed for mounting all that crap and logically conclude there this a LOT of mass sitting off to the sides of the centerline.

The other thing you have to consider about the F-35 is its surface area. A small suface area is better than a surface area any time of the day... any day of the week. The F-35's s.a. is much much larger than an F-16. How much larger I don't know or haven't calculated. But a rough approximation can be done... I remember before computers were widespread that if you needed to calculate the area under a curve and the function was not able to be integrated by hand that you just pull out some weighted paper, trace the curve, cut the paper, and then weigh it on a precision scale. If some wants to do something similar with the F-35 by buying a cheap model and using that technique, then have at it. But its obviously got a huge surface area; another (-) for an air superiority fighter.

So its got 2 strikes against it with mass off the centerline and a large surface area. This is all the result of designing an airplane to do EVERYTHING (including the STOVL) and only giving in ONE engine. You're logically going to get something that is a Jack of all trades and master of none. If the budgets of the 90s were what they were, then we could have gotten a true replacement to the F-16 without limiting it by needing to throw in a lift fan and making it carrier friendly, and ect, ect.

No one here is saying that F-35 definately cannot present a threat to other fighters (when loaded properly) but that it is by no means an air superiority fighter. Its a small precision attack bomber with enough energy to get out of its own way but is by no means on par with an F-22.

Let's wait and see what the Ruskies roll out... If they roll out another "F-35" then fine, go ahead end the Raptor line in 2011 and build up an all F-35 fighter fleet. If they roll out an F-22, then you guys better rethink whats better: the 22 or the 35.

What in hell do the Russians matter? They have very neat things, but time has told us that Russia makes extremely good weapons to say: "Look what we got" and make it look asif their entire military is saturated by them while in reality the bulk of their military still dates back to caveman times.

What in hell do the Russians matter? They have very neat things, but time has told us that Russia makes extremely good weapons to say: "Look what we got" and make it look asif their entire military is saturated by them while in reality the bulk of their military still dates back to caveman times.

What the Russians do does matter because:

1) They export their stuff and there's a certain probability of the USA getting into a skirmish with certain other nations which purchase Russian eqpt.

2) The Russians seem to be holding a grudge against the West being as strong as it is; I wouldn't rule out a conflict with the Russians anylonger. Especially if they elect a West-hating Putin-part-II and he wants to use an Iranian (possible Iranian) attack as a means to launch a attack at the West.

3) Not all of the USSR's hardware was cardboard and water paints.

With possible threats in Korea, China, an Indian-Pakastan conflict, Iran, and with the wildcard, Russia, we should definately be caring about what the Russians roll out and export around the world.

The utopian 1990's of a world all holding hands and hugging tree's is long over. What we have now is not quite as easily summed up in a word like "Cold War" but we definately live on a hostile planet that's ready to kill millions (or billions) over things like, "national pride", race, or the greatest evil of them all... religion. Frankly, I am astonished that we need to defend ourselves over what certain people in certain countries think about what happens in the 'after life' and the great beyond, which is not even a tangible *thing*. We might as well be defending our country against people and nations who believe that leprechans and pixies are telling them to kill the non-believing people so they can pass "Go" and collect their $200 dollars.

First of all, the weight (mass) distribution 'from the centerline' ... has next to nothing to do with 'turn' capability. It directly affects roll rate capability, yes, so it has an effect on how quickly you can bank into a turn - but the actual turn capability ... is a function of lift and weight...

Ok, so you got the point about weight distribution and turnability of an airplane. It seems that every time I want to make a turn in a Piper that the first thing I do is initiate a roll to one direction or another. ... Roll rates directly affect "turnability" of a winged airplane.

And while I, or any outside observer, may not know the *exact* weight distribution, its easy enough for a farm-boy-engineer to look at the F-35 and look at the landing gear location, the gun location, the hydraulics for the gear and weapons bay doors, and the weapons ejection hardware, not to mention the internal structure needed for mounting all that crap and logically conclude there this a LOT of mass sitting off to the sides of the centerline.

The other thing you have to consider about the F-35 is its surface area. A small suface area is better than a surface area any time of the day... any day of the week. The F-35's s.a. is much much larger than an F-16. How much larger I don't know or haven't calculated. But a rough approximation can be done... .... But its obviously got a huge surface area; another (-) for an air superiority fighter

...But in reality, it is even less important than you show. An F-16, for example, rarely uses all of its roll power in a full command roll. .... That is why the ailerons nearly always have more roll power available than needed.

If we now make the assumption that our mass roll inertia (your weight distribution) is somehow arbitrarily doubled (with no other aircraft or FLCS changes, of course)

This is kind of off topic, but I'm just wondering: why do many pilots (and a lot of aeronautical literature) assume that you need to maintain altitude in a turn? This is the familiar situation where you bank to 60 degrees to pull 2 Gs, 71 degrees to pull 3 Gs, and so on... Conversely, if you are pulling 2 Gs, you must be at 60 degrees bank.

People will not say so if you ask them point blank, but I've talked to one pilot who implied that you would go to infinite load factor were you to roll to 90 degrees of bank.....

Raptor claw, there was no intent to criticize your post....

Raptor claw, there was no intent to criticize your post. In fact, it is clear that you are very well grounded in all aspects of flight control, more than I certainly. I was just trying to reinforce your arguments, as I know you already knew what I was saying.

I'm retired now, so don't have direct contact with the F-35, but friends working on it tell me the control system is a real advance over anything else flying, and uses every control surface to give the pilot exactly what he asks for. Sounds great, but a can of worms for a Loads engineer trying to develop a set of design loads for the structure.

What are your friends general impression of the F-35 program? Of course without disclosing any classified material..............Are they excited? What do they think of the many critics out there? Do they think its a worthy successor to the F-16? Just looking for general answers...........