Landing Configuration

[Weegie]

Been spending some time in the 109 practicing landings and takeoffs and reckon I'm now competent (at best)

 

Just a question regarding flaps, trimming and approach speeds when learning to land initially it was Trim -1 and full flaps.

 

However now I don't bother with either flaps or trim (it's always set full nose down) and don't notice any real difference to my stick position or touchdown speed. That's only anectodal I haven't tried to actually quantify it, but it feels like flaps and trim have precious little effect on landing behaviour. Perhaps I use a bit more runway but that seems about it.

 

I'm not a pilot so I don't know so I'm asking the questions

[grafspee]

1 hour ago, Weegie said:

Been spending some time in the 109 practicing landings and takeoffs and reckon I'm now competent (at best)

 

Just a question regarding flaps, trimming and approach speeds when learning to land initially it was Trim -1 and full flaps.

 

However now I don't bother with either flaps or trim (it's always set full nose down) and don't notice any real difference to my stick position or touchdown speed. That's only anectodal I haven't tried to actually quantify it, but it feels like flaps and trim have precious little effect on landing behaviour. Perhaps I use a bit more runway but that seems about it.

 

I'm not a pilot so I don't know so I'm asking the questions

General idea is that at low speeds more travel of trimming system is required.

But it very depends on plane which you are flying. P-47 for example has so sensitive trim system that it in not allowed to change trim at high speeds.

 Bf trimming system is difrent, it changes angle of horizontal stabiliser, so this trim will not affect stick position i think

Edited February 9, 2021 by grafspee

[Weegie]

Thanks @grafspee

 

I've been attemping it with the Spit too, no flaps, no problem. Need to try some more with the Spit though not sure if it's the higher touchdown speed or trim condtion but the Spit's tyres squeal in protest.

 

This is with around 60-70% fuel both with the Spit and the 109, maybe it will be different at higher fuel loads

[grafspee]

14 minutes ago, Weegie said:

Thanks @grafspee

 

I've been attemping it with the Spit too, no flaps, no problem. Need to try some more with the Spit though not sure if it's the higher touchdown speed or trim condtion but the Spit's tyres squeal in protest.

 

This is with around 60-70% fuel both with the Spit and the 109, maybe it will be different at higher fuel loads

Two benefits of full flaps deployed is first you have enormous drag, second is lift. Higher drag allow for steeper approach, avoiding buildings trees is much simpler.

Additional lift decreasing AOA so nose is pointed down this gives you much better visibility.

[Weegie]

32 minutes ago, grafspee said:

Two benefits of full flaps deployed is first you have enormous drag, second is lift. Higher drag allow for steeper approach, avoiding buildings trees is much simpler.

Additional lift decreasing AOA so nose is pointed down this gives you much better visibility.

 

Thanks again, yeah I understand the principles and what the real life effect are, I just question the modelling perhaps being a bit off.

 

In both modules the touchdown speed remains the same and the behavoiur when down on the runway.

 

The 109 feels much the same to land with and without flaps, the Spit (so far) is actually more manageable without them deployed. The screech on the tyres I mentioned with the Spit seems to be the trim. If I trim to +1.0 (second trim marking up from zero) tail heavy it touches down without any hystrionics whatsoever

[grafspee]

34 minutes ago, Weegie said:

 

Thanks again, yeah I understand the principles and what the real life effect are, I just question the modelling perhaps being a bit off.

 

In both modules the touchdown speed remains the same and the behavoiur when down on the runway.

 

The 109 feels much the same to land with and without flaps, the Spit (so far) is actually more manageable without them deployed. The screech on the tyres I mentioned with the Spit seems to be the trim. If I trim to +1.0 (second trim marking up from zero) tail heavy it touches down without any hystrionics whatsoever

It is very hard to determine touch down speed, flaps often makes difference in about 10mph in stall speed, 

another thing is that any additional lift from wings horizontal stab has to induce additional down force so this when you need to re trim plane.

For full answer you will have to ask Yo-Yo

I can touch down spitfire at 100mph as well as at 70mph. 

How you determine that you touch down speed is exact the same, I would say that this is quite hard to show.

Edited February 9, 2021 by grafspee

[Weegie]

Well I'm not a pilot or aerodynamicist, so I'm pretty clueless

 

I just imagined that there would be marked difference in stall speeds and induced drag, which there may well be but its not as noticeable as I thought

 

If I try to put the Spit on the deck at 100mph I can but only briefly as I'm immediatley airborne post haste

 

Thanks for providing the info @grafspee

Edited February 9, 2021 by Weegie

[grafspee]

10mph more with flaps up, with glide approach it is only 5mph you will not notice difference.

Main benefit is that added drag allow you to steep approach.

If you have buildings or any obstacles near airfield and this airfield is short one, you want flaps. 

Edited February 9, 2021 by grafspee

[Wrench]

For warbirds, the main advantages of using the flaps are that it I creases power required, which means higher RPM, which makes the engine more responsive to small corrections, and decreasing required AOA, which allows better visibility, and better "purchase" for the gear.

 

Germans landed three-point, so if you land without flaps you can actually come down tail-wheel first. 

 

The spitfire pilots did the "British push" in which they landed on the main gear, then pushed forward on the stick slightly to "milk" the tailwheel down. The flaps on the spit reduce AOA enough to keep the tail wheel off the ground for that split second it takes to stabilize.