Flap usage on Jabiru's

[Tomo]

So I'm not intending on causing arguments over the matter, but It never ceases to amaze me how many people land a Jabiru with none, or only 1 stage of flap. I guess there is no death penalty involved, but why do it?

 

In the POH is clearly states to land at full flap - nough said

 

Lets look at some of the reasons why I land at full flap all the time, not only because the AFM says so.

 

Flaps are designed to increase lift and consequently, drag. Now that means you will be touching down at a slower speed with full flaps, especially if you hold it off till it stalls.

 

Touching down at a slower speed benefits - The tyre wear (especially on tarmac) You might think to yourself, "yeah but that is only about a 5kt speed reduction" Yes indeed, but it is also 9kph!

 

Ground handling - remember the aircraft doesn't care what it is doing relative to the ground until it touches it. So if you loose directional control one way or another, everything will be happening quicker if your faster.

 

Ground speed is one of the reasons we Land/take off into wind actually, so every little bit does count.

 

When landing on most of the strips I use, I hardly touch the brakes until I need to stop in front of the hanger. That is one huge benefit, especially for the owner of the aircraft.

 

People use first flap for touch and go's because it is a little demanding in those few seconds to get the flap away. It is I agree, especially with the electric flaps, but: I was shown to put power back on 'then' put flaps away 'when' they're those electric ones. But keep it on the ground until they're in position, if you time it right, it works a treat.

 

In saying all that, I always use full flap in the Jab, not only because the book says so, but because it does make life just that little bit easier also.

 

I'd like to hear the reasons people don't use full flap in the Jab, (forgive me those who are still training and being taught that way - Just keep doing what you're told, or maybe ask the instructor next time, and he'll no doubt have a good reason, let us know if you like).

 

BTW - No one has seen flaps until you see the old Cessna barn door type!!!! they're huge! (but that's another subject!)

 

Disclaimer: Please note I'm not an instructor in anyway shape or form, please treat this as a discussion only, not as advice.

 

 

[BigPete]

I'm with you too, Tomo.

 

Only time I don't use full flap is when there is a strong x-wind or I'm expecting very strong sink.

 

When doing T&G's I always use full flap and, let that front wheel come down before removing 2nd stage and then apply throttle.

 

regards

 

PS - The great thing about the electric flaps on the Jabiru is that they are variable - a lttle more or less to suit conditions.

 

 

[Captain]

I agree with BigPete.

 

I fly my 230 in accord with the POH, except in a strong cross or other wind, when I may not go to full flaps.

 

In my view any pilot has an obligation to comply with the POH for the aircraft that he is in.

 

 

[The Wolf]

I only use 1 stage of flaps in a 160 for landing. 2 reasons:

 

1) I was taught that way, and it is his plane so i land how he told me.

 

2) if i start to fall short, it takes a huge amount of throttle to get back onto the glide slope. I am still learning so this usually causes me to start to over-speed on my landings, and hence nose up. Huge risk of stall.

 

I was told to go full flaps if i am coming in too high, or there are thermals on final that push me. I haven't been told not to use full flaps (I have been told to start practicing a few).

 

I think the wear caused by a 9KM faster landing, is negated by the possible damage of a landing going wrong. If you get a strong headwind develop while you are on final, you can drop short quick and cause alot of wear/heating issues by having to go full throttle. I was told you cannot raise flaps once they are down, so you are pretty much commited to that landing. Once you are on the ground, if you start to wheelbarrow or lose control, that flap down is going to hinder you getting airborne as quick as possible.

 

Just my thoughts, i dont have alot of experience so it may all be wrong!

 

 

[jetjr]

Its up to the pilot to operate the AC safely for the airfield he is operating and within his capabilities. Not follow POH blindly. As the HFactors exam taught us...... analyse and manage the risks .

 

At some point downwind I know what Im going to do and bring on flap in two stages depending if second stage is needed or not. When I can I use it (except that bl**dy lever which pops out of stage 2 does influence descisions)

 

More flap slows you down, OK, but results in much steeper approach angle, more agressive flare and can complicate a go around. Controls are also more sluggish and the AC is more prone to float and drift and associated problems. You also have limited ability to alter approach angle and can risk overshooting mark.

 

If you are at a strip which you know well and has 100% more strip than required, with unknown or possible slightly gusty conditions near ground, why not carry the 5kts and land cleanly and positively.

 

Also depends what weight you are at - Jab has had the same wing for LSA55 through to 700kg

 

Your landing skills will have greater impact on touch down speed than just which flap setting you use. Basically work out what works for you and use that - aim is to be as slow as possible when touching ground

 

Wearing out tyres and brakes isnt a consideration

 

 

[Jabiru Phil]

Up until about a year ago I always used full flap. I seemed to be going backwards in my "good" landings for some reason. I remember posting this problem with plenty of advice and mostly fixed it by looking ALONG the runway at flair. Further practice with half flap was really the answer for me. Since then, no more bounces, ballooning, tickling the throttle, aborts etc. The only time I use full flap now is as stated i.e too high, windshear, thermals, tail wind component and near full weight. Amazing the number greasers I do now. The other trick I found was to configure the flaps and trim late downwind instead of base, this gives more time to judge and manage the base point of entry and glide angle., plus look-out time. further advantages as I see it are X-wind landings and further float time to settle down the speed for a smooth landing. I did ask my old CFI if this was exceptable, he said that whatever I feel comfotable with is OK.

 

So, I will stick with this method until my landings go haywire again, hopefully never.

 

Phil.

 

 

[GraemeK]

I've been taught to use half flaps for landing (but previous instructor taught full flaps). Works OK at YLIL where we often have crosswinds - plus I guess it leaves you the option of dropping extra flap if you're high.

 

Note though, that while Jabiru recommends half flap in strong crosswinds, there is no data for landing distances in that configuration in the POH. So yer on yer own in that respect - "Honest yer 'onour, I thought I had plenty of strip .....".

 

 

[BigPete]

A couple of points/observations:

 

1. Don't go to full flap too early - make sure you're going to make the strip - in other words later than sooner.

 

2. To get into shorter strips (especialy those that have high obstacles, trees etc) you will need to use full flap. It's a skill, like all the other bits of flying that you do/practise.

 

3. If you have electric flaps, you can vary the degree of application. So use first flap (around 15%) and then add a little more later (say 25%) until you get comfortable.

 

regards

 

 

[DarkSarcasm]

I've been taught to use half flap for normal landings and full for glide approaches (if needed) and short field landings

 

 

[Thx1137]

I was taught partial flap but find landing easier with full flap. It seems the majority say the POH is the bible so unless there is a reason to do something different then I use it's procedures as the standard.

 

 

[Guest Cloudsuck]

I can offer only three words of advice, 'Flaps ..... as ..... required'.

 

 

[Guest Escadrille]

I'm with Cloudsuck...

 

 

[DarkSarcasm]

I've done lots of flapless landings so the prospect of landing without flaps doesn't bother me terribly (I prefer it in stronger winds really). I like the idea of having full flap 'in reserve' in case I need it (for short field and stuff) and just using half/no flap in normal circumstances (clearly depending upon airfield and weather conditions etc)

 

 

[Guest Andys@coffs]

In mine the flaps are electrically operated, and like all things electrical one day will fail.

 

As such, from time to time, I'll do a flapless landing so that I'm ready for that one day. If that approach was wrong then we wouldn't practice stalls etc because they aren't normal flight maneuvers.

 

It also makes sure that you understand what that extra speed will translate into in terms of increased rollout. Fast and flapless can easily eat a 1000m runway and still have you thinking of fancy options at the end to avoid the upside down attitude..

 

Andy

 

 

[GraemeK]

I've done lots of flapless landings so the prospect of landing without flaps doesn't bother me terribly (I prefer it in stronger winds really). I like the idea of having full flap 'in reserve' in case I need it (for short field and stuff) and just using half/no flap in normal circumstances (clearly depending upon airfield and weather conditions etc)

Nicely put Darky! :thumb_up: :thumb_up:

 

 

[metanoia]

Up until today, I've been using full flap, except for when there's a lot of turbulence and/or crosswind.

 

Today I set 1 stage of flaps in late downwind and maintained 65kts all the way through base and final. Guess what? My first very nice landing. Even my instructor was impressed.

 

Second circuit I set 1 stage of flaps in late downwind and then full on final to lose some height. The Jabbie became somewhat more of a handful to fly and land. Once we were back in the air again, I queried this with my instructor. He seemed to be very much of the "flaps as required" opinion, and said that 55/LSAs can be trickier to land with full flap and that for the most part, it was ok to stay using 1 stage.

 

I think that I'll stick with this as it seems to work for me - which is not to say that I won't also practice with full flaps (and none, of course).

 

 

[Relfy]

As others have said, full flaps in good conditions and lighter winds, varying levels of flap in moderate crosswinds/turbulence according to the conditions.

 

I recall when i test flew a new Jab at Bundy, the pilot taking me explained on downwind and final that in the rougher conditions of the day we'd use 1 stage and 'fly it onto the deck'. Turned out though the conditions weren't too bad on late final and he opted for full flap but still flew it onto the runway with some positive authority.

 

I find flying with different people always sees me picking up little tips and methods that help my own flying.

 

 

[dazza 38]

I can offer only three words of advice, 'Flaps ..... as ..... required'.

I with cloudsuck and the other guys above. eg-In the tecnams, its easier to land in a 15 kt or more crosswind without flap. IMO (along as the runway is long enough etc, etc).

 

 

[Ultralights]

i agree with "Flap as Required" and taking in consideration weight, runway, approach angle, and most importantly Wind and conditions.

 

as a general rule of thumb, windsock angle should dictate flap usage considerations, eg, windsock hanging down vertically = no wind, then full flap.

 

windsock horizontal= strong wind = No flap. 45 degree windsock, you get the picture.

 

do you really need full flap in a J170 solo with only 30 ltrs of fuel on board no baggage? and cleared for a straight in approach with a 5 mile long final. if so, then aim to touchdown at 1.2 stall speed, or, 50 kts thereabouts. or you will float forever.

 

Flaps as required.

 

 

[Tomo]

Thanks all for the replies, has been extremely informative.

 

For those of you who feel like you are "falling" with full flap on, maybe you are leveling out before you get to ground effect, to high?

 

I noticed the same thing, but I now level out and use ground effect, it works stacks better, you get a lot lower though, and will make your passenger wonder!!

 

The reason I reckon it does it, is because when you level out, it slows down pretty quick, (with full flap) so if you aren't at the correct level, it will fall quickly, and you'll have to check it quick. But when you just have one stage of flap or none, it will give some lee way as to how high you level out, and just slow and sink a bit slower.

 

Just a thought?

 

 

[flying dog]

Ok, I'll stick my neck out.

 

We are talking Jab's.

 

A few years ago, I flew to a flyin in a rental.

 

The next day we (a last second drop in passanger) and I went off for an early morning jolly.

 

We quickly realised the weather was turning nasty and so stopped having fun and landed at a nearby fuel stop, refueled and then flew back to the original airstrip.

 

Now, where we landed it was a cross runway, but the wind was on neither. Bugga. A quick phone call told us that it was ok back at the original airstrip so we took off wanting to get back as we had nothing with us, so if we got stuck, we would be in trouble for lack of supplies.

 

Ok, the destination airstrip was 18/36 strip and it was busy-ish as people were flying in for the weekend's flyin in.

 

We got there and the wind was 270/30. I started to line up for a 18 landing, but it was pointed out to me that it was beyond the specs of the plane. Bugga!

 

I quickly checked and there was a SHORT 09/27 strip at the north end. So I aborted the landing and joined for cross wind 27 from base 18 - which would have been final 18.

 

Everyone else was obliging and kept away while we went in for 27. Down wind was quick!

 

Problems:

 

1 - throttle would not go to idel from left seat.

 

2 - manual flaps.

 

3 - other niggily bugs with the plane.

 

Turned final 27. On the EAST side of the strip is a paddock, and on the east side of that is a N/S power line with the big plastic ball on it to help show it. Luckily the poles were higher than the normal ones.

 

On final I had to keep the throttle up to have a positive ground speed and it was about 60+ kts. It was bumpy.

 

I pointed the nose at the ground and just made it over the power lines then leveled out along the paddock. Throttled back as best, and hopped over the fence and landed on the strip with nothing bad happening.

 

Thing is that although I may have been able to deploy flaps, the speed was close to VFE and I didn't want to "push the friendship" with the plane.

 

The "co-pilot" was handy as they helped with the throttle as soon as we hit the ground - pulling it back to idle.

 

I think that each landing needs to be assessed on its own merrits and no "all covering" rule.

 

 

[metanoia]

So, I wonder if height of the pilot has anything to do with flaps preferences?

It could...

 

On the other hand, I'm short (5'6), and I have to say that I prefer landings with 1 stage of flap rather than 2 stages. I find that my visibility is fine, and the Jab is much easier to handle.

 

I've not actually performed a flapless landing as yet - once I have, I'll let you know what I think of them.

 

 

[DarkSarcasm]

So, I wonder if height of the pilot has anything to do with flaps preferences?

For me personally, I'd say no. I'm equally comfortable with flapless landings and landings with half flap. I've only done landings with full flap when doing glide approaches or short field landings.

 

 

[DarkSarcasm]

You must be getting very close to having wings pinned on?

No idea BlackRod I'm currently doing forced landings and I think there's still some more stuff to do after that, plus area solo etc.

 

I really need to get on and learn (and sit) my BAK though...

 

 

[DarkSarcasm]

If you need an incentive (as if) - I'm catching up! I've done the RA-Aus BAK (I think you were going to do the GA BAK?) and last week passed Human Factors. The latter is the hardest exam to pass because it is so hard to study without falling off your chair zzzzzz zzzzz and the exam feels like a guessing competition!

Oh no, I'd better hurry up! :thumb_up:

 

Yes, I'm planning to do GA BAK. I just find the entire BAK thing fairly daunting - seems a lot of information to learn... Did you self-study? I need to remember it's multiple choice too, I've probably got a 50/50 chance on any question I don't know!

 

I think I need to sit down on the weekend and spend a day just doing BAK and tell myself that I can't feel guilty that I'm studying that rather than doing law study...