Forum: General F-22A Raptor forum

johnwill wrote:

Moving vertical tails forward, as in the F-18, does indeed help with high alpha stability, but only if there are twin tails moved outboard as far as possible. But sprstdlyscottsman is right that stability is reduced for such a move at normal alpha. That's why the F-18 VT area (and drag and weight and cost) is about twice that of the F-16.

Agreed. I was talking about the F22 at high alpha, though.

Quote:

CG position is still important to fly by wire airplanes. There are still aft cg limits which must be observed, even if aft cg is beneficial in maneuvering.

Yes, but a shift of vertical stab of a, let's say 2 feet, shouldn't really make F22 leave CCV boundaries. F-104G (CCV testbed for EF) had a 750kg of dead weight in the end of tail and was still able to fly with unadjusted wing surfaces.
F22 verticals generate enough lift to carry themselves and more. Red somewhere a study about it and pros and cons of hypothetical straightening of verticals. As it turned out, the drag reduction was far less rewarding than a lift contribution and range gain by slanted verticals.

Quote:

And vertical tails only contribute to lift if they are angled outboard, On the F-15 for example, they contribute nothing to lift.

Yes well, we are talking about F22.

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cywolf32 wrote:

Agreed. It's interesting to say the least that the subject in hand is without merit. I'm getting a "Skyhigh" vibe here.....

I think I just evacuated in my sweatpants. Shocked

Raptors don't want or need moveable intakes- not very stealthy equipment for them, are they?

Nice to see Raptor_DCTR around here again! Thumb

If I'm not mistaken the main reason for the F-22's angled Vert. tails is stealth. Perpendicular surfaces are beautiful radar targets.

Tinito is probably right, but another good reason to tilt them outboard is to put them in higher energy air as mentioned earlier by cola.

Without any elaboration: The Inlet and vertical tail ....they move!

winger2 wrote:

Without any elaboration: The Inlet and vertical tail ....they move!

Yep, they sure do, through the air, in very close formation with the rest of the airplane...

Rolling Eyes

winger2 wrote:

TINITO: CHECK SITE AIRLINERS.NET. SEARCH F-22. AT THE PHOTOS GO TO PAGE 3 PIC #7. THE F-22 IS AIRBORN AND IT IS VERY EVAIDENT THE WHOLE INLET IS MOVED FORWARD. IF YOU CAN NOT FINED THIS PIC, TRY CLICKING ON OTHER PHOTOS UNTIL YOU FINED A PROPER PHOTO SHOWING THE INLETS MOVED FORWARD. iT IS VERY HARD TO MISS. iT APPEARS TO BE A CARRY OVER FROM THE F-15.

WINGER2 ( I TRIED TO SEND YOU AN E-MAIL ATTACHMENT BUT MY SERVER SAID YOUR E-MAIL ADDRESS WAS NOT A VALID INTERNET ADDRESS.)

I use google to access AIRLINERS.NET.

winger2 wrote:

Without any elaboration: The Inlet and vertical tail ....they move!

Well, yeah, we're all going around the sun, right?

You have yet to 1) Explain what you see adequately so we can see what you're saying, or 2) Accept that what you saw was an illusion, which seems to be the consensus.

In short, No, they don't.

winger2 wrote:

Without any elaboration: The Inlet and vertical tail ....they move!

Hello all...first time post....been lurking for a few months though and have followed this topic for awhile....didn't respond before but since it's popped up again figured I'd do it now.....

I work in Marietta as an engine mech on the 22.......I 100% assure you Winger2 that they do not move. I'm around the aircraft every day, I've jumped intakes for inspections, I've done nozzle maintanace on top of the aircraft 2 inches away from the stabs.....they do not in any way, shape or form move...at all!

Is that the sound of a door slamming shut? Hmm? Wink

ledblimp: I guess Led Zeppelin was already taken? Laughing

ledblimp: I guess Led Zeppelin was already taken? Laughing

[/quote]

Actually, had a supervisor that used to refer to Zep as ledblimp and it was kind of a joke around the shop. Always kinda liked it. I'm sure if I had tried tho Led Zeppelin would've been taken already.

Active Member Joined: Jun 01, 2004 - 08:55 AM Posts: 134

TO ALL: winger2 was kind enough to email me the pictures where he based his assumptions upon. In order for us to be in the same page with him, I guess I should post the pictures here, along with his actual comments (as per his exact email to me).

And winger2, as what everybody say here, the F-22s inlets are indeed fixed. The variations you're seeing are actually optical illusions (looks like they're changing/moving but they're not) brought about by the design of the aircraft to achieve stealth.

#1

Fretmarks: Look at picture #1. THE INLET is not in the pure vertical. My guess is it is 10--20 degrees left of vertical.
also LOOK at the bottom of the Inlet, not the top. If you were to draw a straight line from the air frame (from landing gear to bottom of Inlet) you will see it is curved up, my guess is 3-4 degrees. this CAN NOT BE because of the F-22's Diamond shaped Inlets!!

#2

Now look at picture #2. Again, draw a straight line from the air frame (landing gear forward)
to the Inlet you can see that the bottom is curved DOWN (3-4 degrees?) If you look at F-22 photos you will see this Inlet configuration ONLY when it seems the aircraft is in a gentle bank. Why? don't have a clue. And last, if I'm seeing "ghost" please tell me how the Inlets get from picture #1 to picture #2 without moving? (also notice in picture #2 the Inlet NOW is 20-30 degrees(?) right of vertical) I would have uploaded pictures to the forum, but I tried and failed, guess in my old age I don't understand all this comp. tech.

Do we have an emoticon for beatin' a dead horse yet? I guess Rolling Eyes

will have to suffice.

Well here is what I see... in those Raptor photos is perspective.

The center line of the aircraft is not the green line (Nose to gear), nor is it the blue line (Nose to hook). The green line is distorted due to the length of the gear and the up-slope of the nose to the tip. The blue line is also distorted by the up-slope of the nose and the hook. The red line (down the centerline between the weapons bays) is right down the center. But by the looks of it, the red line is too low in relation to the nose and hook?

The yellow inlet lines (drawn from upper to lower 'corner' of the inlets) are also distorted as one would terminate across the forward centerline while the other does not.

Why? Perspective!

Now look at the 'plan' view of the aircraft. The inlets rake, inboard to out, forward to aft.

Now why would the inlets of any aircraft move differentially? Inlets schedule as a function of airspeed. (NOT throttle, or engine RPM like nozzles) Even IF one engine were shut down, the inlets would still move together. There is no reason ONLY ONE would move in a turn or any other maneuver.

I'll further illustrate my point, REF SR-71 graphic.

The white line is not center line (canopy to canopy to nose) but the green line isn't either (Nose to tail) The AR door doesn't move left/right, nor do the canopies. We all know the Blackbirds wings are not 'movable' but one leading edge would terminate across the aft canopy, while the other doesn't.

Why? Perspective.

There are too many angles and compound curves to an aircraft to 'eyeball' angles and features you're describing. Look at photos of Super Hornets, or Tomcats; F-14 inlets only moved internally, so do not move in photos. Look closely at the perspective of the inlets in similar turns or banks. The inlets will have noticeably different shapes and shadows associated with them; all perspective!

Keep 'em flyin' Thumb

TEG

Forum: General F-22A Raptor forum

F-22 Intake's & Vertical tail.