My rant/fantasy regarding the A-10(A&B) Warthog.

So do everyone the common curtsey of answering/looking up the most basic of prerequisite questions before spewing ignorance and then getting mad when ones complete and utter BS ignorant postings are called BS ignorant postings:

How does an airplane fly? What forces are involved and WHERE are they involved? If you the reader cannot be bothered to either know or look these facts up, how is anyone supposed to have a discussion? I say the color is black, you see whatever the hell you wish to see(usually based out of Hollywood idiocy) and the next post is an entirely different color.

Lets put it this way: Even 10 and 12 year olds at an RC airplane field know how to balance an airplane and how it flies...

Hutch wrote:I respectfully non-concur. A little grumpiness and snarkery should be allowed in heated discussions, as long as they don't become the focus of the replies or lead to Godwinning of the thread (if you don't get the reference, google Godwin's law).

What I would like to see is some evidence, since right now we have Relax and MAD-4A basically saying "You don't know aerodynamics!!" "Oh yeah, well YOU don't know aerodynamics!!" A little evidence on one of their parts would be rather apprecaited (and in terms somebody the same age as the Lockheed constellation can understand, please).

It's almost a non-issue to me... The rotating engine nacelles idea I mean.

That will add additional cost to the plane, and in this time of constricted budgets, it will be the same as designing a new aircraft. i.e.: An added expense that would endanger the aircraft to NOT getting any sort of upgrade or replacement.

Building new frames or refurbishing old ones, then moving/cannibalizing equipment from one old airframe over to a new or refurbished airframe is a lot more likely to happen.

...that is, _IF_ such an idea ever gets any support from the (AF) Brass or the civilian leadership (and the Army).



.

Relax wrote:Guess everyone who designed harrier, F35B, Osprey V-22, and Tilt wing aircraft for STOL and where their thrust lines can be in comparison to the CG of the aircraft are all stupid!

no. they know what they are doing - "VTOL" "Vertical Take Off or Landing" not "limited" "STOL" "Short Take Off or Landing".

MAD-4A wrote:

Relax wrote:Guess everyone who designed harrier, F35B, Osprey V-22, and Tilt wing aircraft for STOL and where their thrust lines can be in comparison to the CG of the aircraft are all stupid!

no. they know what they are doing - "VTOL" "Vertical Take Off or Landing" not "limited" "STOL" "Short Take Off or Landing".

All those planes do STOL as a major portion of their flight profile. It allows them to carry significantly more weight than VTOL. 2-4X in the Osprey's case.

For God's sake and my sanity, draw an elementary FBD for the A-10 and answer your own statement on weather an A-10 can rotate its engines or not for STOL. Where is the CG again? Which way is the lift moment on the main wing again...? Does rotating the engines increase or decrease this moment... What is Newton's laws of motion again? For every force there is an EQUAL and OPPOSITE force... DOH! Damned Newton!

There are exactly 2 planes on this earth that can do "limited" STOL. Well, 3 and maybe 4 actually if you count demonstrator aircraft.

The A-10 is not one of them.

Give ya a MAJOR hint. None of them are sub sonic aircraft. Do you have any idea why?

Hutch wrote:What I would like to see is some evidence, since right now we have Relax and MAD-4A basically saying "You don't know aerodynamics!!" "Oh yeah, well YOU don't know aerodynamics!!" A little evidence on one of their parts would be rather apprecaited (and in terms somebody the same age as the Lockheed constellation can understand, please).

of-course…


( http://www.nationalmuseum.af.mil/shared/media/photodb/photos/060829-F-1234S-024.jpg & http://www.boeingimages.com/Docs/BOE/Media/TR3_WATERMARKED/6/4/1/8/BI212052.jpg - too big to load)


These are all rocket assist units, they use the thrust of a rocket engine angled down to provide more lift on takeoff, allowing for STOL, S for “shorter than normal”. Of course the rockets have to be lined up with the aircrafts center of mass because you can’t have thrust off center...oh wait, they aren’t…hmmm….guess the thrust of an aircraft on takeoff doesn’t need to be lined up with the center of mass. Yes, there is some difference than with using a planes internal engines but the physics are the same.

Relax wrote:All those planes do STOL...

They are VTOL aircraft (do you know the difference?) capable (as any fixed wing VTOL aircraft is) of STOL operations as-well. This means that they have to be able to have their thrust line up VERTICALY (not horizontally) with their center of mass to keep from flipping over. They also have the option (as with some other aircraft) to vector their thrust some, not all the way, to give added lift while preforming a rolling takeoff, hence STOL.

Relax wrote:There are exactly 2 planes on this earth that can do "limited" STOL. Well, 3 and maybe 4 actually if you count demonstrator aircraft. None of them are sub sonic aircraft.

last I looked, the F-80, F-86s, Harriers (except the AV-8B model) nor UAVs are supersonic, did you hear about a new model of F-80 that’s supersonic? I haven’t.

Relax wrote:The A-10 is not one of them.

Never said it is one, I said it would be a nice feature to add, but I agree that with current budget battles it’s not a priority at the moment.
Maybe before being snarky you should make sure your right, even then, if you get something right, no-one would admit it.

MAD-4A wrote:Of course the rockets have to be lined up with the aircrafts center of mass because you can’t have thrust off center...oh wait, they aren’t…

Oh yes they are. That's the reason they're mounted so far forward on the fuselage -- a line drawn through the centerline of the JATA units will either parallel the direction of flight or pass through the center of gravity.

Where are those rockets attached?
Where is the CG...
What is a moment again...
Force times what again, oh yea distance.

Where is the thrust line on said rockets pointing? DIRECTLY THROUGH THE CG of said craft or directly BELOW! Therefore any change in AoA will create a NOSE UP orientation(moment) which is compensated via the horizontal stabilizer, not NOSE DOWN as would happen on the A-10 requiring a larger DOWN force on the horizontal stabilizer to compensate! IE on your proposed engine swivel on the A-10 to keep it balanced would create an EQUAL and OPPOSITE force required pointing DOWN on the horizontal stabilizer!

Holy crap man. Elementary physics. Definition of a moment!

*** Where is the MAC of an airfoil subsonic and supersonic... elementary aerodynamics.***

Guys designing aircraft for the last 100 years are not stupid!

Relax wrote:There are exactly 2 planes on this earth that can do "limited" STOL. Well, 3 and maybe 4 actually if you count demonstrator aircraft.

The A-10 is not one of them.

Give ya a MAJOR hint. None of them are sub sonic aircraft. Do you have any idea why?

Perhaps an expanded post with the definition of "limited" STOL you are using.

Just want to make sure I understand what you mean.

You posted while I was composing. Not everybody understands what you mean by "moment".

I do but that is just because being on a ship in the shipyard while they tried to correct said moment. Otherwise I would be seriously clueless (well more than usual anyway).

Have fun,
T2M

thinkstoomuch wrote:

Relax wrote:There are exactly 2 planes on this earth that can do "limited" STOL. Well, 3 and maybe 4 actually if you count demonstrator aircraft.

The A-10 is not one of them.

Give ya a MAJOR hint. None of them are sub sonic aircraft. Do you have any idea why?

Perhaps an expanded post with the definition of "limited" STOL you are using.

Just want to make sure I understand what you mean.

You posted while I was composing. Not everybody understands what you mean by "moment".

I do but that is just because being on a ship in the shipyard while they tried to correct said moment. Otherwise I would be seriously clueless (well more than usual anyway).

Have fun,
T2M

Using its engines to take off.

F-22 and Su-35(derivatives thereof) are the only planes on earth able to do so. Why>?

Subsonic all airfoils have their center of pressure near the 25% of chord. Supersonic aircraft have their center of pressure at 50% chord. 4 things allow this gigantic swing in stability to not crash every plane when they go supersonic.

1) Detla wing allows for higher static margin(chord length between CG and NP(neutral point)
2) Large horizontal stabilizers
3) A lot of pilots died figuring this out.
4) Fly by wire systems able to compensate for this inherent instability(computers) IE yo-yo-ing on take-off/landing most notably. Gets back to before computers, a lot of pilots died crashing highly unstable jets on TO/Landing.

Thus, a supersonic aircraft like the F-22 and Su-35 are designed for supersonic flight and therefore have their balance point near the 50% point. Therefore when they takeoff their actual aerodynamic balance point is at 25%. Thrust vectoring engines can make up the difference between 25% and 50% when on the ground and can force a "pop-up" maneuver at low velocity via computer control.
1) Sufficient Vel is obtained
2) Thrust now points slightly down
--- forces nose in air before horizontal stabilizers on their own could have done so
--- creates higher AoA on wing and therefore higher lift
3) Thrust immediately goes back to level if not slightly up to compensate for the moment the wing is creating as the horizontal stabilizers cannot compensate at this low of velocity yet. Depends where the CG is in comparison to its AoA(Angle of Attack)
4) Immediately go back to level thrust.

IE the vectored thrust creates a nose down moment about the CG, but because we are in subsonic region, the center of pressure on the aircraft is well AHEAD of the CG making the aircraft highly unstable, so by using vectored thrust, not only does the stability INCREASE, but TO distance decreases, or conversely total aircraft weight can increase for same TO distance traveled.

PS.
If anyone does not understand what a "moment" is and is posting in this thread on a science fiction forum concerning swiveling engines as reality on aircraft that have to balance about a singular point(CG), they should be banned for Trolling abject ignorance.