Does the nose balloon up and are trim changes necessary after slats are extended? Does it depend on the aircraft? Am mostly interested in the DC-10 and MD-11 but would value information on any aircraft?
Which leading/trailing edge flap or slat settings require the largest trim changes?
I mentioned in a previous post that lack of slats on the DC-9-15 seemed to give it a definite nose down attitude all the way to landing although slight pitch variations could be felt all the way down.
Thanks for any information.
Moderators: richierich, ua900, PanAm_DC10, hOMSaR
-
- GalaxyFlyer
- Posts: 9180
- Joined:
Re: What does slat extension do to the attitude of an aircraft on approach?
If you maintain the same speed, not very noticeable on the types I have flown and not much if you slow. Flaps create more trim change.
Re: What does slat extension do to the attitude of an aircraft on approach?
As galaxy said, it shouldn’t be much if anything. Although not strictly true it was always useful for me to think about slats altering your Clmax and flaps altering your zero lift line, the ballooning happening because you effectively just changed the AoA (by moving the zero point).
Fred
Sent from my iPad using Tapatalk
Fred
Sent from my iPad using Tapatalk
-
- GalaxyFlyer
- Posts: 9180
- Joined:
Re: What does slat extension do to the attitude of an aircraft on approach?
The F-100 had Handley-Page slats that moved as a function of AoA. We’d fly around in close formation, dive bomb recovery, fighting wing and never even think about the slats. I’d guess if one side hung up, it would exciting. In 1G, they came out at about 290, you could see them moving while in formation. The pattern and initial was blown at 300, so they’d be in until maybe the echelon turn to initial and you’d see lead’s slats go in and out.
Re: What does slat extension do to the attitude of an aircraft on approach?
convair880mfan wrote:Does the nose balloon up and are trim changes necessary after slats are extended? Does it depend on the aircraft? Am mostly interested in the DC-10 and MD-11 but would value information on any aircraft?
Which leading/trailing edge flap or slat settings require the largest trim changes?
I mentioned in a previous post that lack of slats on the DC-9-15 seemed to give it a definite nose down attitude all the way to landing although slight pitch variations could be felt all the way down.
Thanks for any information.
You mention the MD-11 a fair amount recently - why that aircraft?
-
- GalaxyFlyer
- Posts: 9180
- Joined:
Re: What does slat extension do to the attitude of an aircraft on approach?
Now, a slatted wing will produce a more nose up attitude on final—slats create a wider working range of AoA for the wing.
-
- Starlionblue
- Posts: 21060
- Joined:
Re: What does slat extension do to the attitude of an aircraft on approach?
The A330 has a noticeable pitch up when you extend the slats (and first step of flaps which is almost nothing). Call it from 4 to 8 degrees nose up to maintain level flight at around 220 knots. If you're hand-flying you need to put in some forward stick to avoid ballooning. Once the flaps come out, the pitch goes back to about 5 degrees.
There's a trim change, obviously, but automatic since it is an Airbus.
There's a trim change, obviously, but automatic since it is an Airbus.
Re: What does slat extension do to the attitude of an aircraft on approach?
convair880mfan wrote:Which leading/trailing edge flap or slat settings require the largest trim changes?
convair880mfan, on the Airbus A320 series, the largest trim change requirement, in my opinion, occurs inflight when going from Flaps 1 to Flaps 2.
Inflight, when you select Flaps 1, the leading edge slats extend to 18 degrees while the flaps remain retracted. Then, when selecting Flaps 2, the leading edge slats further extend to 22 degrees and the flaps extend to 15 degrees. The autotrim system responds with forward (nose down) trim, which seems to be slightly more than when transitioning between other flap settings.
e38
Who is online
Users browsing this forum: No registered users and 17 guests