Retracting Flaps
 

Retracting flaps.....on final. Never done it. Never ever even suggested it.

But looking at V speeds and suchlike, I wonder if in an engine out forced landing, when one already had flaps out to some extent, what would happen if one retracted them? Assuming of course you were over stalling speed.

Would your glide flatten out? Would you fall out of the sky?

In other words, if you screw up a glide approach by dumping too much flap, what happens if you realise the error of your ways and decide to pull some up?

caution This does not appear to be part of the PPL syllabus.

Thanking youse in advance for an answer to this silly question.

Errr ummm... THIS is what happens when you dump flaps on final.

http://users.netconnect.com.au/~njah1/jab1a.jpg



http://users.netconnect.com.au/~njah1/jab1b.jpg

Your glide will improve, but you will get a significant change in trim and nose attitude (you'll have to keep the nose higher to maintain the speed). It's easy to lose significant height doing it, so make sure you have enough!

Some interesting discussion on 'slipping cessnas' thread re. accurate approaches and flap.

Just saw XXX's pictures, certainly don't 'dump flap on final', but easing some flap off early in the approach will have the desired effect

go and try it u will not die and it is not a big deal to do so. Try dropping flap while in the landing flare but make sure u increase backpressure or ull nose in to the ground. These work well in piper aircraft. Also another good one is jacking flap as a round and see if ur instructo no what this is. Commercial operators use both at times when a short feild may be being used

Highflyer, fair's fair mate, that's hardly a safe option.

What is the purpose of dropping the flaps in the landing flare as you put it? Wouldn't leaving the flaps down, particularly in a head wind actually HELP you to reduce speed during braking?

"Also another good one is jacking flap as a round and see if ur instructo no what this is. Commercial operators use both at times when a short feild may be being used"

Well, I guess you must be right, I'm just another dumb instructor and commercial operator who has no idea what you're talking about.

Errr....What this gentleman seems to be suggesting is that you go out in an aircraft and try something you have never been taught and which doesn't appear in any manual I've ever seen.

If you are doing it in someone Else's aircraft I suggest you get their permission first, before promoting yourself to test pilot!!!

As to the original question, the way to "Stretch" a glide is to fly at the best L/D speed for the configuration you are in. If you are at, say, flap 30 and flying faster than the best glide speed for that setting, retracting flap will,in fact, reduce your glide angle.There will be a significant trim change (usually nose down) and a need to fly a different attitude.

If you are AT the best glide speed for flap 30, retracting flap will put you BELOW the best L/D for the new setting. You would need to speed up (i.e dive) to get to the new best L/D speed, eating up height, so if you are already low it's not necessarily a good idea.

No easy answer, I'm afraid, but,as always, it depends upon the aircraft and situation you are in at the time.

It is a non event in Cessnas.

Back when Paul Hardy (RIP) was teaching me glide approaches pre first solo and later practicing enroute engine failures/forced landings, he taught me to use flap 'like a throttle'. Thoughtfull use of flap on final approach on PFLs was extremely interesting and allowed you to move your aim point back and forth to a limited extent (obviously). Going from flaps 20 back to flaps 10, for instance...or even back to clean...could be used to fine tune your aiming point if falling a little short...and then reselect more flap as desired later in the approach or just prior to the landing flare.

Part of the Roberston Stol kit on many Missionary C206s in PNG was a big red button on the control column...that dumped flaps rapidly from whatever they were selected to back to zero. It worked well...really well.

That doesn't mean you can dump the flaps in the flare and then sit there thumb in bum - mind in neutral...it does take a modest amount of skill and forethought.

VH XXX Fair enough but know coz the flaps still providing lift there is less weight on the ground there for greater breaking distance and its more for short feilds where u want to hit ur spot an as I said mainly works for piper A/C a cherokee 6 is a prime example of an aircraft that it works well on and if you have flown one ull no what i mean

What on earth does this mean? Surely our education system hasn't sunk this low. Not meaning to pick on you Highflyer, but if one cannot use the correct pronunciation don't bother posting at all. We're not texting here.

Retracting flaps whilst on final approach, although dangerous, is just downright rude!
NAVERICK can back me up on this, but a few moons ago, whilst chatting up a LOVELY lass in a not to shabby establishment, all was going well, I moved in for the FINAL kill, when SHE "retracted flaps" and left me to crash and burn!!!

BLOODY rude.... so, for gods sake... never ever do it!!!