This whole "On Speed" thing....how does it work?

[wlawr005]

 

[nittany03]

Sort of like that airplane on a treadmill thing...

We're not going there. Again. Oh, the brain cells wasted . . .

 

[Random Task]

In a -45 you are not actually trimming to AOA like you are in an -18. in a 45, the trim sets where neutral stick position is which means where the stab is. When you roll out in the grove, a different stab position is required than what was holding you on speed downwind.

 

[scoober78]

 

[armada1651]

In a -45 you are not actually trimming to AOA like you are in an -18. in a 45, the trim sets where neutral stick position is which means where the stab is. When you roll out in the grove, a different stab position is required than what was holding you on speed downwind.

I'm not an aero engineering guy by any means, but this is basically what I was going to say. My guess is that it has to do with the decrease in lift and resulting decrease in induced drag as you you increase your rate of descent through the approach turn. I think that could be significant enough to require you to adjust the stab position. But I've never noticed a need to do that in the F-18, because there you're not telling the stabs to go to a certain position when you trim, you're telling the FCCs to have every control surface on the jet (except the spoilers) constantly adjust to maintain a specified AOA.

 

[Harrier Dude]

You have spoilers in a Hornet?

 

[C420sailor]

Different airplanes behave differently. The Rhino doesn't really give half a shit about what you have your trim set to once you start moving the throttles. If you start out balls on-speed and try flying the ball without corresponding stick inputs (influencing the nose), you're going to show paddles all sorts of red and green, with a little amber mixed in. I've heard that the Hornet is better about maintaining on-speed on its own, but I can't speak to that.

 

[BusyBee604]

Different airplanes behave differently.

Those four words sum it up nicely. Comparing trim v optimum A/A procedures of different type aircraft, is comparing apples to oranges.
BzB

 

[armada1651]

You have spoilers in a Hornet?

Two small panels on the LEX in the Rhino, one big one between the tails on the Hornet.

 

[Renegade One]

Kinda cool…39 AW posts for what may have been covered with some fidelity over a cup of coffee or a beer with said IP…assuming s/he's available for/willing to take "chalk talks" without recrimination. Not that there's anything wrong with hearing tons of good stuff.

There was a time when knowing/reading all of this would have been better than "Do some of that pilot shit…" behind the boat as a RAG RIO Instructor.

 

[F8Driver]

Alright, I've never been accused of being the sharpest knife in the drawer, but this has me somewhat confused...

If I am flying downwind in a Clown Jet, configured gear down, flaps full, boards out and trimmed on-speed (which is a big assumption for my SNA self, I realize)...and I roll into my approach turn without touching the trim, shouldn't I be on speed once again when I roll out of the approach turn on the ball?

What I'm seeing is that the jet seems to need a few clicks of nose-up trim on final to keep from going fast, even though it was trimmed on-speed on the downwind. My question is why this happens? Shouldn't the jet seek the same AOA it was trimmed for regardless of whether I am climbing, descending, flying upwind, downwind etc...

Yes, Scoober, I realize I'm completely geeking out...

Each airframe is unique in the way it responds to power in the dirty configuration. The F-4 was incredibly speed stable and was as close to a 100% left hand airplane on the ball as any I've flown. The F-14 required constant small attitude adjustments to remain on speed while making power corrections. The T-45 is somewhat in-between ... I tell my students it's an 85% left hand airplane; mostly power corrections with minute nose corrections. As your power is reduced approximately 3-400PPH on glideslope versus level, the neutral trim point is effected slightly.

Best technique to to approach the start with the last 10-20 degrees of turn fading out angle of bank, fading out power, and using those few seconds for the aircraft to decel in airspeed as you maintain on speed AOA and pick up your nominal rate of descent. A click of trim may be required.

 

[MIDNJAC]

Yeah, the Hornet (legacy that is) is pretty rock solid once trimmed on speed with power adjustments. I was a repeat offender early on with influencing the nose, but that generally meant that my left hand wasn't doing what it was supposed to be doing.