Landing with reduced airbrake

[Richard McLean[_2_]]

Hi guys,

Our club is having a discussion about the merits of reducing airbrake on
short final (well before the flare) in order to reduce the rate of descent
on
the last part of finals - in particular after using full airbrake to
correct an
overshoot i.e. you are still overshooting but reduce the airbrake to the
normal 1/2 to 2/3 range & just accept the overshoot.

This relates in particular to gliders which have a 2 point attitude which
is
quite low e.g. DG-1001 (nosewheel with retractable main) & LS8 .. a fully-
held off low energy landing in these types results in touching tail first,
and
in concert with a high rate of descent with full airbrake makes a hard tail

strike more likely.

Any thoughts or similar experience?

Cheers,

Richard McLean
Beverley Soaring Society
Western Australia

[son_of_flubber]

Your question was recently kicked around in this forum

https://groups.google.com/forum/#!searchin/rec.aviation.soaring/Round$20out$20and$20flare$20with$20fully$20open$20 spoilers$20in$20a$20PW-6|sort:date/rec.aviation.soaring/m7AnPvT2knQ/5AXqN0EyCQAJ

[Richard McLean[_2_]]

Ah ok, must have missed that one - thanks!

At 02:56 15 May 2018, son_of_flubber wrote:
>Your question was recently kicked around in this forum
>
>https://groups.google.com/forum/#!searchin/rec.aviation.soaring/Round$
20out$20and$20flare$20with$20fully$20open$20spoile rs$20in$20a$20PW-
6|sort:date/rec.aviation.soaring/m7AnPvT2knQ/5AXqN0EyCQAJ
>

[Richard McLean[_2_]]

Hi again flubber,

I just re-read (most of!) that thread .. an I do remember it now.

It doesn't really address my question which is (to paraphrase):

In gliders with a low angle of attack 2 point attitude (e.g. DG-1001 & LS8)

does anyone else find that trying to land with lots of airbrake inevitable

results in a tail-strike, and therefore reducing the airbrake to (let's
say) 1/2
at around 100 ft or so is advsed?

Cheers,

Richard

At 02:56 15 May 2018, son_of_flubber wrote:
>Your question was recently kicked around in this forum
>
>https://groups.google.com/forum/#!searchin/rec.aviation.soaring/Round$
20out$20and$20flare$20with$20fully$20open$20spoile rs$20in$20a$20PW-
6|sort:date/rec.aviation.soaring/m7AnPvT2knQ/5AXqN0EyCQAJ
>

[kirk.stant]

On Monday, May 14, 2018 at 10:30:05 PM UTC-5, Richard McLean wrote:
> Hi again flubber,
>
> I just re-read (most of!) that thread .. an I do remember it now.
>
> It doesn't really address my question which is (to paraphrase):
>
> In gliders with a low angle of attack 2 point attitude (e.g. DG-1001 & LS8)
>
> does anyone else find that trying to land with lots of airbrake inevitable
>
> results in a tail-strike, and therefore reducing the airbrake to (let's
> say) 1/2
> at around 100 ft or so is advsed?

I'm not sure why the concern for a tail-first touchdown. Unless you snatch the stick back at the last moment, or are really slow and stalled and basically falling, a tailwheel first touchdown (when fully held off with low descent rate) is not going to hurt the plane - and guarantees the lowest touchdown speed and no bounce, if that is the goal, by rotating the wing to a lower AOA when the tail touches.

I try for the tail to touch first when I land my LS6, and at most it touches just before the main. Really hard to get that tail down further!

That being said, if going into a really short field, I want a good sink rate and the tail touching first for a really short landing run. You can burn off a bit of energy by a firm touchdown (just don't get carried away!)

If you have the luxury of easing off the brakes on final, then you are going for style points instead of landing distance, and it's more a matter of how much brake you like out when you flare and land. But not a good idea to be sawing on the airbrakes on short final!

Cheers

Kirk
66

[Scott Williams]

On Monday, May 14, 2018 at 9:45:05 PM UTC-5, Richard McLean wrote:
> Hi guys,
>
> Our club is having a discussion about the merits of reducing airbrake on
> short final (well before the flare) in order to reduce the rate of descent
> on
> the last part of finals - in particular after using full airbrake to
> correct an
> overshoot i.e. you are still overshooting but reduce the airbrake to the
> normal 1/2 to 2/3 range & just accept the overshoot.
>
> This relates in particular to gliders which have a 2 point attitude which
> is
> quite low e.g. DG-1001 (nosewheel with retractable main) & LS8 .. a fully-
> held off low energy landing in these types results in touching tail first,
> and
> in concert with a high rate of descent with full airbrake makes a hard tail
>
> strike more likely.
>
> Any thoughts or similar experience?
>
> Cheers,
>
> Richard McLean
> Beverley Soaring Society
> Western Australia

Hey Richard,
In my very limited experience and humble opinion, any medium to large spoiler changes made after overflying the aim point and just above the ground (say 5 feet or less)only complicate the landing and promote P.I.O.s (for me anyway)
I have been transitioning from an SHK to a std Cirrus, with an increased wing loading by about 45%. I have found the emphasis on low energy landing and 'delaying the touchdown' very helpful. In short, just before touchdown is a little late to shed excess energy.
So, if safe to do so, accept the overshoot in favor of a desirable soft touchdown. Of course, if limited in 'runout room' adjust accordingly.
Best of luck,
Scott
only induce

[Richard McLean[_2_]]

On Tuesday, 15 May 2018 12:13:46 UTC+8, kirk.stant wrote:
> On Monday, May 14, 2018 at 10:30:05 PM UTC-5, Richard McLean wrote:
> > Hi again flubber,
> >
> > I just re-read (most of!) that thread .. an I do remember it now.
> >
> > It doesn't really address my question which is (to paraphrase):
> >
> > In gliders with a low angle of attack 2 point attitude (e.g. DG-1001 & LS8)
> >
> > does anyone else find that trying to land with lots of airbrake inevitable
> >
> > results in a tail-strike, and therefore reducing the airbrake to (let's
> > say) 1/2
> > at around 100 ft or so is advsed?
>
> I'm not sure why the concern for a tail-first touchdown. Unless you snatch the stick back at the last moment, or are really slow and stalled and basically falling, a tailwheel first touchdown (when fully held off with low descent rate) is not going to hurt the plane - and guarantees the lowest touchdown speed and no bounce, if that is the goal, by rotating the wing to a lower AOA when the tail touches.
>
> I try for the tail to touch first when I land my LS6, and at most it touches just before the main. Really hard to get that tail down further!
>
> That being said, if going into a really short field, I want a good sink rate and the tail touching first for a really short landing run. You can burn off a bit of energy by a firm touchdown (just don't get carried away!)
>
> If you have the luxury of easing off the brakes on final, then you are going for style points instead of landing distance, and it's more a matter of how much brake you like out when you flare and land. But not a good idea to be sawing on the airbrakes on short final!
>
> Cheers
>
> Kirk
> 66

Gday Kirk,

The concern is that students are breaking tailwheels in our DG-1001. The latest one probably form a loss of energy after a higher than optimal flare.

We have an old DG-1000 with a much higher 2 point nose attitude and it hasn't been an issue in 10 years or so .. but our brand-new DG-1001 (with nosewheel & much lower main wheel) has a much lower 2 point attitude which means that with a high rate of descent e.g. full brake and/or too slow the glider can touch down heavily on the tailwheel & it bursts.

One suggestion was that we limit the rate of descent for students by getting them to reduce airbrakes prior to the landing - even if they are still overshooting. A very experienced pilot suggested reducing the airbrake (if it's full for an overshoot) at around 100 ft to moderate the rate of descent and help prevent the tail-strike described. His theory is that some gliders with a small 2 point attitude are more prone to this.

Cheers,

Richard

[Richard McLean[_2_]]

On Tuesday, 15 May 2018 12:20:38 UTC+8, Scott Williams wrote:
> On Monday, May 14, 2018 at 9:45:05 PM UTC-5, Richard McLean wrote:
> > Hi guys,
> >
> > Our club is having a discussion about the merits of reducing airbrake on
> > short final (well before the flare) in order to reduce the rate of descent
> > on
> > the last part of finals - in particular after using full airbrake to
> > correct an
> > overshoot i.e. you are still overshooting but reduce the airbrake to the
> > normal 1/2 to 2/3 range & just accept the overshoot.
> >
> > This relates in particular to gliders which have a 2 point attitude which
> > is
> > quite low e.g. DG-1001 (nosewheel with retractable main) & LS8 .. a fully-
> > held off low energy landing in these types results in touching tail first,
> > and
> > in concert with a high rate of descent with full airbrake makes a hard tail
> >
> > strike more likely.
> >
> > Any thoughts or similar experience?
> >
> > Cheers,
> >
> > Richard McLean
> > Beverley Soaring Society
> > Western Australia
>
> Hey Richard,
> In my very limited experience and humble opinion, any medium to large spoiler changes made after overflying the aim point and just above the ground (say 5 feet or less)only complicate the landing and promote P.I.O.s (for me anyway)
> I have been transitioning from an SHK to a std Cirrus, with an increased wing loading by about 45%. I have found the emphasis on low energy landing and 'delaying the touchdown' very helpful. In short, just before touchdown is a little late to shed excess energy.
> So, if safe to do so, accept the overshoot in favor of a desirable soft touchdown. Of course, if limited in 'runout room' adjust accordingly.
> Best of luck,
> Scott
> only induce

Thanks Scott,

Not suggesting any airbrake/spoiler changes near the aiming point - much earlier at about 100ft only.

Cheers,

Richard

[Peter F[_2_]]

If your pupills are regularly approaching with full brake then they need to
improve their circuit planning rather than changing airbrake setting at
lowish level.

The last thing they should be doing is getting into the habit of
approaching too high / too fast then reducing brake. This will eventually
lead to them running into the hedge of a short field when outlanding

Regards

PF

[SF]

Teaching low time students to make less than full spoiler deployments early on final, then leaving them alone so that they can concentrate a good landing that may not be in the exact desired spot may be a good way to start.

Most landing issues are the result of choices made much earlier in the pattern. Tighten up the instruction in the rest of the pattern.

There are too many variables for new students to adjust at the same time, so nail some of them down, airspeed, turn to base altitude, turn to final altitude. You can loosen those up later. Fine control of the spoilers near the ground shouldn't be attempted for awhile.

Tail first or main wheel landings, those are just style points, either can be done gently. Work on the decisions made earlier to result in some consistency that the students can handle without banging up the aircraft.

[Richard McLean[_2_]]

On Tuesday, 15 May 2018 19:30:07 UTC+8, Peter F wrote:
> If your pupills are regularly approaching with full brake then they need to
> improve their circuit planning rather than changing airbrake setting at
> lowish level.
>
> The last thing they should be doing is getting into the habit of
> approaching too high / too fast then reducing brake. This will eventually
> lead to them running into the hedge of a short field when outlanding
>
> Regards
>
> PF

OK, I think I need to re-phrase my question .. I understand everything you're saying (I'm an experienced instructor) but my question is not about how to teach circuits/approaches/landings it's whether anyone else flying performance "training" gliders like the DG-1000 has had lot's of student tail-strikes, and whether there is any merit in reducing the airbrake to avoid the need for a tail-first high rate of descent landing?

We have 2 DG-1000's - an older tail-dragger with a high undercarriage which lands only slightly tail-first in a fully held-off low energy landing, and a newer nose-wheel version with a lower height main wheel which seems to land much harder on the tail - hence a possible problem with bursting tail wheels when a student lands heavy from correcting an overshoot with nearly full air-brake - we just had our first one.

I suspect that the new nose wheel configuration DG-1000 has a lower wing incidence wing than most traditional trainers (for performance) & with the deletion of the original high main wheel configuration this has now resulted in an aircraft more susceptible to hard tail-strikes .. and as we have purchased it as a primary trainer I'm trying to determine if we need to restrict the amount of air-brake used by students when correcting overshoots in order to avoid tail-strikes/burst tail-wheels. We have a long runway, so it would just mean a long push-back with lots of time to debrief what went wrong with the overshoot!

[[email protected]]

I was taught to land the glidr in the same attitude as it sits on the ground. I have always followed this practice, and have 300 landings
with no problems. One particular DG 1000 owning club does not like me not holding off the glider until it stalls on, resulting in a tail wheel first landing.
I find this attitude plain stupid.

[Richard McLean[_2_]]

On Wednesday, 16 May 2018 10:27:08 UTC+8, wrote:
> I was taught to land the glidr in the same attitude as it sits on the ground. I have always followed this practice, and have 300 landings
> with no problems. One particular DG 1000 owning club does not like me not holding off the glider until it stalls on, resulting in a tail wheel first landing.
> I find this attitude plain stupid.

Thanks Mike. Do you ever find that if using more than 1/2 air-brake you need to reduce it before the flare? The theory is that slightly tail first is best, so that you're definitely low-energy & the nose pitches down rather than the reverse .. but I land my Astir 2 point if I can!

Cheers,

Richard

[George Haeh]

Newer gliders with powerful air brakes will lose airspeed rapidly in the flare. Flaring too high or from an inadequate airspeed, especially with powerful air brakes full on, can end in a hard landing.

Perhaps the tailplane in the taller gear variants of the DG-1000/1 produces more lift as it rotates around the main gear to cushion the tailwheel contact.

A less tall gear does increase the possibility of a tailwheel first landing.

Another consideration is the amount of tail ballast carried.

Have you noticed if there's a difference with heavier or lighter pilots in the front seat?

It might be useful to have two experienced pilots, one to video and take notes, to do landings at various airspeeds and CGs to determine optimal landing parameters - and determine what to avoid.

[Richard McLean[_2_]]

Thanks for that George - yes, a bit of experimentation might be a good idea.

One of our most experienced pilots says the LS8 requires an airbrake reduction to avoid excessive tail-first landings, so perhaps it's the same with this configuration DG-1000.

Cheers,

Richard

On Wednesday, 16 May 2018 11:35:57 UTC+8, George Haeh wrote:
> Newer gliders with powerful air brakes will lose airspeed rapidly in the flare. Flaring too high or from an inadequate airspeed, especially with powerful air brakes full on, can end in a hard landing.
>
> Perhaps the tailplane in the taller gear variants of the DG-1000/1 produces more lift as it rotates around the main gear to cushion the tailwheel contact.
>
> A less tall gear does increase the possibility of a tailwheel first landing.
>
> Another consideration is the amount of tail ballast carried.
>
> Have you noticed if there's a difference with heavier or lighter pilots in the front seat?
>
> It might be useful to have two experienced pilots, one to video and take notes, to do landings at various airspeeds and CGs to determine optimal landing parameters - and determine what to avoid.

[Richard McLean[_2_]]

And no, we've only just started flying the glider, so no observations about differing pilot weights/CG position as yet.

On Wednesday, 16 May 2018 11:47:10 UTC+8, Richard McLean wrote:
> Thanks for that George - yes, a bit of experimentation might be a good idea.
>
> One of our most experienced pilots says the LS8 requires an airbrake reduction to avoid excessive tail-first landings, so perhaps it's the same with this configuration DG-1000.
>
> Cheers,
>
> Richard
>
> On Wednesday, 16 May 2018 11:35:57 UTC+8, George Haeh wrote:
> > Newer gliders with powerful air brakes will lose airspeed rapidly in the flare. Flaring too high or from an inadequate airspeed, especially with powerful air brakes full on, can end in a hard landing.
> >
> > Perhaps the tailplane in the taller gear variants of the DG-1000/1 produces more lift as it rotates around the main gear to cushion the tailwheel contact.
> >
> > A less tall gear does increase the possibility of a tailwheel first landing.
> >
> > Another consideration is the amount of tail ballast carried.
> >
> > Have you noticed if there's a difference with heavier or lighter pilots in the front seat?
> >
> > It might be useful to have two experienced pilots, one to video and take notes, to do landings at various airspeeds and CGs to determine optimal landing parameters - and determine what to avoid.

[[email protected]]

I try to get the bulk of braking done during final, and to flare at about half brake. i havent however, had any problems with full brake landings.
I dont stress about not flying the glider on a bit either, and neverr have trouble with bounces.
I had a partciularly nasty experience in an old twin Astir, when a gust just after a fully held off landing lifted the nose and caused a very heavy landing, despite closing the brakes very quickly.

[Bruce Hoult]

On Wednesday, May 16, 2018 at 1:36:56 PM UTC+12, Richard McLean wrote:
> On Tuesday, 15 May 2018 19:30:07 UTC+8, Peter F wrote:
> > If your pupills are regularly approaching with full brake then they need to
> > improve their circuit planning rather than changing airbrake setting at
> > lowish level.
> >
> > The last thing they should be doing is getting into the habit of
> > approaching too high / too fast then reducing brake. This will eventually
> > lead to them running into the hedge of a short field when outlanding
> >
> > Regards
> >
> > PF
>
> OK, I think I need to re-phrase my question .. I understand everything you're saying (I'm an experienced instructor) but my question is not about how to teach circuits/approaches/landings it's whether anyone else flying performance "training" gliders like the DG-1000 has had lot's of student tail-strikes, and whether there is any merit in reducing the airbrake to avoid the need for a tail-first high rate of descent landing?
>
> We have 2 DG-1000's - an older tail-dragger with a high undercarriage which lands only slightly tail-first in a fully held-off low energy landing, and a newer nose-wheel version with a lower height main wheel which seems to land much harder on the tail - hence a possible problem with bursting tail wheels when a student lands heavy from correcting an overshoot with nearly full air-brake - we just had our first one.
>
> I suspect that the new nose wheel configuration DG-1000 has a lower wing incidence wing than most traditional trainers (for performance) & with the deletion of the original high main wheel configuration this has now resulted in an aircraft more susceptible to hard tail-strikes .. and as we have purchased it as a primary trainer I'm trying to determine if we need to restrict the amount of air-brake used by students when correcting overshoots in order to avoid tail-strikes/burst tail-wheels. We have a long runway, so it would just mean a long push-back with lots of time to debrief what went wrong with the overshoot!

My club has had two of the DG1000 Club training gliders for a decade. We are also familiar with the full-spec DG1000 as a nearby club we often fly with has (had?) one.

I'm sure there's no difference in wing incidence between them. We were told as late as one week before our gliders went to the port that it was "not too late" to upgrade to retractable undercarriage, 20m tips (as well as the 18m we got), water etc.

It's simply that with the lower undercarriage the wing is at lower angle of attack *on the ground*. Not in flight.

It's very obvious when we've been flying both together on the same day that both the liftoff and touchdown speeds (and corresponding distances) for our training gliders are noticeably higher than for the glider with higher and retractable undercarriage.

I'm pretty sure we've had no more problem with burst tail wheel tyres than with any other glider .. the Grobs we had before the DGs, for example.

The important thing is that with the shorter undercarriage you are (or should be) nowhere near actual stall speed at touchdown. A "fully held off" landing is one in which you allow the nose pitch angle to increase in the hold off until it is the same as it is when sitting on the ground AND NOT MORE. If the main and tail wheels touch down together (or very slightly tail first) then there no no possibility of a bounce.

It is a slightly unfortunate aspect of these gliders that you shouldn't fully stall them on landing, and thus land a bit faster. But with correct technique of flying to the same attitude as they sit on the ground they are no problem.

[Richard McLean[_2_]]

On Wednesday, 16 May 2018 13:11:12 UTC+8, Bruce Hoult wrote:
> On Wednesday, May 16, 2018 at 1:36:56 PM UTC+12, Richard McLean wrote:
> > On Tuesday, 15 May 2018 19:30:07 UTC+8, Peter F wrote:
> > > If your pupills are regularly approaching with full brake then they need to
> > > improve their circuit planning rather than changing airbrake setting at
> > > lowish level.
> > >
> > > The last thing they should be doing is getting into the habit of
> > > approaching too high / too fast then reducing brake. This will eventually
> > > lead to them running into the hedge of a short field when outlanding
> > >
> > > Regards
> > >
> > > PF
> >
> > OK, I think I need to re-phrase my question .. I understand everything you're saying (I'm an experienced instructor) but my question is not about how to teach circuits/approaches/landings it's whether anyone else flying performance "training" gliders like the DG-1000 has had lot's of student tail-strikes, and whether there is any merit in reducing the airbrake to avoid the need for a tail-first high rate of descent landing?
> >
> > We have 2 DG-1000's - an older tail-dragger with a high undercarriage which lands only slightly tail-first in a fully held-off low energy landing, and a newer nose-wheel version with a lower height main wheel which seems to land much harder on the tail - hence a possible problem with bursting tail wheels when a student lands heavy from correcting an overshoot with nearly full air-brake - we just had our first one.
> >
> > I suspect that the new nose wheel configuration DG-1000 has a lower wing incidence wing than most traditional trainers (for performance) & with the deletion of the original high main wheel configuration this has now resulted in an aircraft more susceptible to hard tail-strikes .. and as we have purchased it as a primary trainer I'm trying to determine if we need to restrict the amount of air-brake used by students when correcting overshoots in order to avoid tail-strikes/burst tail-wheels. We have a long runway, so it would just mean a long push-back with lots of time to debrief what went wrong with the overshoot!
>
> My club has had two of the DG1000 Club training gliders for a decade. We are also familiar with the full-spec DG1000 as a nearby club we often fly with has (had?) one.
>
> I'm sure there's no difference in wing incidence between them. We were told as late as one week before our gliders went to the port that it was "not too late" to upgrade to retractable undercarriage, 20m tips (as well as the 18m we got), water etc.
>
> It's simply that with the lower undercarriage the wing is at lower angle of attack *on the ground*. Not in flight.
>
> It's very obvious when we've been flying both together on the same day that both the liftoff and touchdown speeds (and corresponding distances) for our training gliders are noticeably higher than for the glider with higher and retractable undercarriage.
>
> I'm pretty sure we've had no more problem with burst tail wheel tyres than with any other glider .. the Grobs we had before the DGs, for example.
>
> The important thing is that with the shorter undercarriage you are (or should be) nowhere near actual stall speed at touchdown. A "fully held off" landing is one in which you allow the nose pitch angle to increase in the hold off until it is the same as it is when sitting on the ground AND NOT MORE. If the main and tail wheels touch down together (or very slightly tail first) then there no no possibility of a bounce.
>
> It is a slightly unfortunate aspect of these gliders that you shouldn't fully stall them on landing, and thus land a bit faster. But with correct technique of flying to the same attitude as they sit on the ground they are no problem.

Thanks for that Bruce - by referring to the wing incidence I didn't mean that the 2 models were any different, just that the AoA in the 2 point attitude is different - exactly what you said. I was inplyingg that high-performance gliders like the DG-1000 probably have less wing/fuselage incidence that previous training aircraft .. less drag etc. etc.

Cheers,

Richard

[Matt Herron Jr.]

from my perspective, reducing airbrakes at 100' changes your glide slope and therefor aim point half way through final. So do you give up your initial aim point at 100', or do you have two aim points? Either option seems like a bad idea for students.

Airbrake deployment should be a driven variable to maintain a correct approach, not the other way around.

Additionally, a shallower approach for the last 100' means you are way more susceptible to wind shear, as you don't have much "extra" glide to recover by closing the airbrakes.

To me, it sounds like the tail strike problem is in the flair, not the use of airbrakes.

[George Haeh]

The DG-1000 Club seems a good illustration of the law of unintended consequences. Having the fixed gear as far down as the retractable version would impose a significant drag penalty, but having it higher up imposes a higher takeoff and touchdown speed.

The electric gear version can fail to come down. The flight manual recommends practicing the emergency gear down mechanism periodically. I know of one gear up landing where the Instructor had not practiced the emergency gear down.

[Richard McLean[_2_]]

On Thursday, 17 May 2018 06:58:54 UTC+8, George Haeh wrote:
> The DG-1000 Club seems a good illustration of the law of unintended consequences. Having the fixed gear as far down as the retractable version would impose a significant drag penalty, but having it higher up imposes a higher takeoff and touchdown speed.
>
> The electric gear version can fail to come down. The flight manual recommends practicing the emergency gear down mechanism periodically. I know of one gear up landing where the Instructor had not practiced the emergency gear down.

This is what I think too - the original design had the high main-wheel but people wanted easier cockpit access so they gave it the lower main/nose wheel combination .. which has compromised the landing attitude. All well & good, but it does now expose the tail-wheel to some serious abuse by students! I guess any "do everything" performance glider is going to be compromised to some extent - in this case as a club ab-initio trainer. I still think the best mitigation (as an instructor) is to actively limit the rate of descent if required.

[Richard McLean[_2_]]

On Wednesday, 16 May 2018 22:21:48 UTC+8, Matt Herron Jr. wrote:
> from my perspective, reducing airbrakes at 100' changes your glide slope and therefor aim point half way through final. So do you give up your initial aim point at 100', or do you have two aim points? Either option seems like a bad idea for students.
>
> Airbrake deployment should be a driven variable to maintain a correct approach, not the other way around.
>
> Additionally, a shallower approach for the last 100' means you are way more susceptible to wind shear, as you don't have much "extra" glide to recover by closing the airbrakes.
>
> To me, it sounds like the tail strike problem is in the flair, not the use of airbrakes.

Hi Matt, yes you give up the original aim point. This isn't ideal but better than damaging the aircraft? The debrief can cover off the reasons. Lots of bad landings are the result of not accepting that you stuffed up your original aiming point & concentrating on the actual landing.

[Bruce Hoult]

On Thursday, May 17, 2018 at 1:43:09 PM UTC+12, Richard McLean wrote:
> On Wednesday, 16 May 2018 22:21:48 UTC+8, Matt Herron Jr. wrote:
> > from my perspective, reducing airbrakes at 100' changes your glide slope and therefor aim point half way through final. So do you give up your initial aim point at 100', or do you have two aim points? Either option seems like a bad idea for students.
> >
> > Airbrake deployment should be a driven variable to maintain a correct approach, not the other way around.
> >
> > Additionally, a shallower approach for the last 100' means you are way more susceptible to wind shear, as you don't have much "extra" glide to recover by closing the airbrakes.
> >
> > To me, it sounds like the tail strike problem is in the flair, not the use of airbrakes.
>
> Hi Matt, yes you give up the original aim point. This isn't ideal but better than damaging the aircraft? The debrief can cover off the reasons. Lots of bad landings are the result of not accepting that you stuffed up your original aiming point & concentrating on the actual landing.

I'd think if you were so high turning final that you can't get back on to a standard half brake approach by, say, 100m before crossing the fence then you've well and truly stuffed up the circuit. Especially in something with airbrakes as powerful as a DG1000 or Grob. You definitely should never be planning to carry full brake all the way down the approach ... that leave nothing in reserve for the unexpected.

[Jonathon May]

At 06:36 17 May 2018, Bruce Hoult wrote:
>On Thursday, May 17, 2018 at 1:43:09 PM UTC+12, Richard McLean wrote:
>> On Wednesday, 16 May 2018 22:21:48 UTC+8, Matt Herron Jr. wrote:
>> > from my perspective, reducing airbrakes at 100' changes your glide
>slop=
>e and therefor aim point half way through final. So do you give up your
>in=
>itial aim point at 100', or do you have two aim points? Either option
>seem=
>s like a bad idea for students.
>> >=20
>> > Airbrake deployment should be a driven variable to maintain a correct
>a=
>pproach, not the other way around.
>> >=20
>> > Additionally, a shallower approach for the last 100' means you are
way
>=
>more susceptible to wind shear, as you don't have much "extra" glide to
>rec=
>over by closing the airbrakes.
>> >=20
>> > To me, it sounds like the tail strike problem is in the flair, not
the
>=
>use of airbrakes.
>>=20
>> Hi Matt, yes you give up the original aim point. This isn't ideal but
>bet=
>ter than damaging the aircraft? The debrief can cover off the reasons.
>Lots=
> of bad landings are the result of not accepting that you stuffed up your
>o=
>riginal aiming point & concentrating on the actual landing.
>
>I'd think if you were so high turning final that you can't get back on to
>a=
> standard half brake approach by, say, 100m before crossing the fence
then
>=
>you've well and truly stuffed up the circuit. Especially in something
with
>=
>airbrakes as powerful as a DG1000 or Grob. You definitely should never be
>p=
>lanning to carry full brake all the way down the approach ... that leave
>no=
>thing in reserve for the unexpected.

Trick one
I have not flown the DG1001 neo yet but I have quite a lot of time in the
original DG1000,you need a step to get people in,if that is the angle for
2point landing them the newer versions going to land tail wheel first .

I have done hundreds of trial flights in an early DG500 that everyone said
was "over braked" ,in fact it could be .But as all I wanted was to get the
punters down safe without a hard landing I tend to add 5kns and gently fly
it on, on the main wheel.
The trouble with that is its not the correct method to teach landing to
pupils.

As I said tricky
My advice would be to buy a K21 or Duo xl ,they fly as you would expect.

>

[Papa3[_2_]]

On Tuesday, May 15, 2018 at 11:47:10 PM UTC-4, Richard McLean wrote:
> Thanks for that George - yes, a bit of experimentation might be a good idea.
>
> One of our most experienced pilots says the LS8 requires an airbrake reduction to avoid excessive tail-first landings, so perhaps it's the same with this configuration DG-1000.
>
> Cheers,
>
> Richard
>
> On Wednesday, 16 May 2018 11:35:57 UTC+8, George Haeh wrote:
> > Newer gliders with powerful air brakes will lose airspeed rapidly in the flare. Flaring too high or from an inadequate airspeed, especially with powerful air brakes full on, can end in a hard landing.
> >
> > Perhaps the tailplane in the taller gear variants of the DG-1000/1 produces more lift as it rotates around the main gear to cushion the tailwheel contact.
> >
> > A less tall gear does increase the possibility of a tailwheel first landing.
> >
> > Another consideration is the amount of tail ballast carried.
> >
> > Have you noticed if there's a difference with heavier or lighter pilots in the front seat?
> >
> > It might be useful to have two experienced pilots, one to video and take notes, to do landings at various airspeeds and CGs to determine optimal landing parameters - and determine what to avoid.

I owned an LS8 for about 13 years, so figure about 450-500 takeoffs and landings. I don't remember anything special about the flare and touchdown. The POH is very clear that with airbrakes fully extended one needs to carry additional airspeed and that a slip with full airbrakes is not recommended.. That said, I never had any trouble stuffing the glider into some fairly short spaces.

I can see a scenario where the pilot is coming in right at the minimum approach speed and full divebrakes, mis-judging the roundout, and hauling back on the stick resulting in a very firm arrival. But the same applies to other gliders. I once borrowed a friends ASW-20 (original version) and demonstrated a max-performance approach with full flaps. Roundout, touchdown, and "oh sh***" all in one smooth motion :-)

P3

[Bruce Hoult]

On Thursday, May 17, 2018 at 9:00:15 PM UTC+12, Jonathon May wrote:
> At 06:36 17 May 2018, Bruce Hoult wrote:
> >On Thursday, May 17, 2018 at 1:43:09 PM UTC+12, Richard McLean wrote:
> >> On Wednesday, 16 May 2018 22:21:48 UTC+8, Matt Herron Jr. wrote:
> >> > from my perspective, reducing airbrakes at 100' changes your glide
> >slop=
> >e and therefor aim point half way through final. So do you give up your
> >in=
> >itial aim point at 100', or do you have two aim points? Either option
> >seem=
> >s like a bad idea for students.
> >> >=20
> >> > Airbrake deployment should be a driven variable to maintain a correct
> >a=
> >pproach, not the other way around.
> >> >=20
> >> > Additionally, a shallower approach for the last 100' means you are
> way
> >=
> >more susceptible to wind shear, as you don't have much "extra" glide to
> >rec=
> >over by closing the airbrakes.
> >> >=20
> >> > To me, it sounds like the tail strike problem is in the flair, not
> the
> >=
> >use of airbrakes.
> >>=20
> >> Hi Matt, yes you give up the original aim point. This isn't ideal but
> >bet=
> >ter than damaging the aircraft? The debrief can cover off the reasons.
> >Lots=
> > of bad landings are the result of not accepting that you stuffed up your
> >o=
> >riginal aiming point & concentrating on the actual landing.
> >
> >I'd think if you were so high turning final that you can't get back on to
> >a=
> > standard half brake approach by, say, 100m before crossing the fence
> then
> >=
> >you've well and truly stuffed up the circuit. Especially in something
> with
> >=
> >airbrakes as powerful as a DG1000 or Grob. You definitely should never be
> >p=
> >lanning to carry full brake all the way down the approach ... that leave
> >no=
> >thing in reserve for the unexpected.
>
> Trick one
> I have not flown the DG1001 neo yet but I have quite a lot of time in the
> original DG1000,you need a step to get people in,if that is the angle for
> 2point landing them the newer versions going to land tail wheel first .
>
> I have done hundreds of trial flights in an early DG500 that everyone said
> was "over braked" ,in fact it could be .But as all I wanted was to get the
> punters down safe without a hard landing I tend to add 5kns and gently fly
> it on, on the main wheel.
> The trouble with that is its not the correct method to teach landing to
> pupils.
>
> As I said tricky
> My advice would be to buy a K21 or Duo xl ,they fly as you would expect.

Not necessary. All you need to do is fly close to the ground and gradually slow and increase the pitch until you are in the same attitude as you would be on the ground.

Assuming you have levelled out at the correct height for your undercarriage length it all works out just the same as any other glider. Main wheel is skimming just a few inches above the ground, once the AOA gets to the point that the tail wheel touches gently you physically can't increase the pitch more, and do the main will gently drop on.

Whether the glider is actually "stalled" at that point or not is irrelevant..

If you level out a DG1000 Club at the same height as you would a standard DG1000, and then slow until it stalls, then you're going to be dropping on hard from a foot up no matter what you do. Know how it looks out the window of your glider when it's on the ground!

[Richard McLean[_2_]]

At 01:40 18 May 2018, Bruce Hoult wrote:
>On Thursday, May 17, 2018 at 9:00:15 PM UTC+12, Jonathon May
wrote:
>> At 06:36 17 May 2018, Bruce Hoult wrote:
>> >On Thursday, May 17, 2018 at 1:43:09 PM UTC+12, Richard
McLean wrote:
>> >> On Wednesday, 16 May 2018 22:21:48 UTC+8, Matt Herron Jr.
wrote:
>> >> > from my perspective, reducing airbrakes at 100' changes your
glide
>> >slop=3D
>> >e and therefor aim point half way through final. So do you give up
your
>> >in=3D
>> >itial aim point at 100', or do you have two aim points? Either
option
>> >seem=3D
>> >s like a bad idea for students.
>> >> >=3D20
>> >> > Airbrake deployment should be a driven variable to maintain a
>correc=
>t
>> >a=3D
>> >pproach, not the other way around.
>> >> >=3D20
>> >> > Additionally, a shallower approach for the last 100' means you
are
>> way
>> >=3D
>> >more susceptible to wind shear, as you don't have much "extra"
glide to
>> >rec=3D
>> >over by closing the airbrakes.
>> >> >=3D20
>> >> > To me, it sounds like the tail strike problem is in the flair, not
>> the
>> >=3D
>> >use of airbrakes.
>> >>=3D20
>> >> Hi Matt, yes you give up the original aim point. This isn't ideal
but
>> >bet=3D
>> >ter than damaging the aircraft? The debrief can cover off the
reasons.
>> >Lots=3D
>> > of bad landings are the result of not accepting that you stuffed up
>you=
>r
>> >o=3D
>> >riginal aiming point & concentrating on the actual landing.
>> >
>> >I'd think if you were so high turning final that you can't get back
on
>t=
>o
>> >a=3D
>> > standard half brake approach by, say, 100m before crossing the
fence
>> then
>> >=3D
>> >you've well and truly stuffed up the circuit. Especially in something
>> with
>> >=3D
>> >airbrakes as powerful as a DG1000 or Grob. You definitely should
never
>b=
>e
>> >p=3D
>> >lanning to carry full brake all the way down the approach ... that
leave
>> >no=3D
>> >thing in reserve for the unexpected.
>>=20
>> Trick one
>> I have not flown the DG1001 neo yet but I have quite a lot of time in
the
>> original DG1000,you need a step to get people in,if that is the
angle
>f=
>or
>> 2point landing them the newer versions going to land tail wheel first

[Phil Plane]

I guess the difference between the DG1000 with the tall gear and the DG 1000 with the short gear is similar to the difference between the Duo Discus with the short gear and the newer Duo X or XL with the tall gear. The minimum approach speed is a few knots faster with the short gear.

I regularly fly the original Duo, the Duo with the X wing and the short gear, a Duo X, and occasionaly the XL. The tall gear is the easiest.

Flying the short gear gliders after you're used to the tall gear you have to be careful not to land slow with the main still half a meter in the air.

Landing any of them like you're meant to (min speed all the way to the holdoff) and they're fine. Let the speed decay on short finals and the short gear will punish you worse than the tall gear.

I've flown the tall gear DG1000 a lot and like it. I haven't flown the short gear DG1000, but I have flown the DG500 and 505 with the short gear. I think the difference is comparable.

Tall is more forgiving and just generally better. Short lets old people get in the glider easier.

[Richard McLean[_2_]]

On Friday, 18 May 2018 14:00:42 UTC+8, Phil Plane wrote:
> I guess the difference between the DG1000 with the tall gear and the DG 1000 with the short gear is similar to the difference between the Duo Discus with the short gear and the newer Duo X or XL with the tall gear. The minimum approach speed is a few knots faster with the short gear.
>
> I regularly fly the original Duo, the Duo with the X wing and the short gear, a Duo X, and occasionaly the XL. The tall gear is the easiest.
>
> Flying the short gear gliders after you're used to the tall gear you have to be careful not to land slow with the main still half a meter in the air..
>
> Landing any of them like you're meant to (min speed all the way to the holdoff) and they're fine. Let the speed decay on short finals and the short gear will punish you worse than the tall gear.
>
> I've flown the tall gear DG1000 a lot and like it. I haven't flown the short gear DG1000, but I have flown the DG500 and 505 with the short gear. I think the difference is comparable.
>
> Tall is more forgiving and just generally better. Short lets old people get in the glider easier.

Thanks for that Phil

[CindyB[_2_]]

On Friday, May 18, 2018 at 12:25:02 AM UTC-7, Richard McLean wrote:

You have a couple options to 'soften' the touch/sink rate, but you know those....

1) add a couple knots of approach speed and buy time to feel for(get closer to) ground.
2) lessen spoilers near the ground to lengthen the flaring and 'feel for ground time'.

Neither of those teaches what you really seek, which is -- Identification of the chosen attitude.

One technique I find helpful for students to reinforce or identify ANY desired touching attitude is to seat the student with closed canopy on the runway threshold (or adjacent). Have a helper level the tip, and you walk to the empennage. Using a hand on the empennage centerline, you can rocking chair the glider to show nose-low attitude (forward 2-point), nose-level attitude for liftoff and your described almost-preferred touchdown attitude, and the nose-high tail-low 2-point attitude.

This rocking chair exercise can be repeated prior to any flight by using your launch helpers. It helps the student define the look -- comparing the panel top or side rails of cockpit to comparative external visual keys.

It doesn't matter what glider is used. The new-pilot trainee needs to 'see' the chosen attitude several times - and contrast it to the 'wrong' attitudes. This is a Cheap and Effective tool to assist a student who might be struggling with the rapidly changing and Brief moments of touchdown finesse..

Good luck to you and the students, with wishes for smooth touches.

Cindy B
Mojave, CA

[Richard McLean[_2_]]

On Wednesday, 23 May 2018 12:05:28 UTC+8, CindyB wrote:
> On Friday, May 18, 2018 at 12:25:02 AM UTC-7, Richard McLean wrote:
>
> You have a couple options to 'soften' the touch/sink rate, but you know those....
>
> 1) add a couple knots of approach speed and buy time to feel for(get closer to) ground.
> 2) lessen spoilers near the ground to lengthen the flaring and 'feel for ground time'.
>
> Neither of those teaches what you really seek, which is -- Identification of the chosen attitude.
>
> One technique I find helpful for students to reinforce or identify ANY desired touching attitude is to seat the student with closed canopy on the runway threshold (or adjacent). Have a helper level the tip, and you walk to the empennage. Using a hand on the empennage centerline, you can rocking chair the glider to show nose-low attitude (forward 2-point), nose-level attitude for liftoff and your described almost-preferred touchdown attitude, and the nose-high tail-low 2-point attitude.
>
> This rocking chair exercise can be repeated prior to any flight by using your launch helpers. It helps the student define the look -- comparing the panel top or side rails of cockpit to comparative external visual keys.
>
> It doesn't matter what glider is used. The new-pilot trainee needs to 'see' the chosen attitude several times - and contrast it to the 'wrong' attitudes. This is a Cheap and Effective tool to assist a student who might be struggling with the rapidly changing and Brief moments of touchdown finesse.
>
> Good luck to you and the students, with wishes for smooth touches.
>
> Cindy B
> Mojave, CA

Cheers Cindy.

You're right, the key to avoiding a hard tail-strike is not pulling past the correct landing attitude .. unfortunately I think when a high rate of descent is present the instinct is to keep pulling, hence the focus on addressing the rate of descent. I guess the answer is to address both issues.

Thanks again,

Richard

[Tim Taylor]

I am not an instructor, but have done many real life off field landings. I don’t understand why you would be wanting to do landings with full spoilers? The goal is minimum energy at the point of touch down, not maximum spoilers. The perfect approach would be with a glide angle 50% between full spoilers and no spoilers. That would have shown you have capability to adapt to any change in conditions. A full spoiler landing shows the pilot was too high and miss judged the approach.

My target on off field landings is to be stalling the plane on with the tail wheel touching just before the main. The only situation that calls for a full spoiler landing is clearing an obstacle on final. That should be an advanced maneuver, not standard practice.

So yes, less than full spoilers are the way to teach landings, and better for the aircraft.

[krasw]

Yes, occasionally outlanding requires flying over obstacles like trees. And occasionally the field is shorter than your home airfield. Then you would probably make full airbrakes approach.

[Tango Eight]

On Wednesday, May 23, 2018 at 2:49:32 PM UTC-4, Tim Taylor wrote:
> I am not an instructor, but have done many real life off field landings. I don’t understand why you would be wanting to do landings with full spoilers? The goal is minimum energy at the point of touch down, not maximum spoilers. The perfect approach would be with a glide angle 50% between full spoilers and no spoilers. That would have shown you have capability to adapt to any change in conditions. A full spoiler landing shows the pilot was too high and miss judged the approach.
>
> My target on off field landings is to be stalling the plane on with the tail wheel touching just before the main. The only situation that calls for a full spoiler landing is clearing an obstacle on final. That should be an advanced maneuver, not standard practice.
>
> So yes, less than full spoilers are the way to teach landings, and better for the aircraft.

Hi Tim,

I see things very differently.

Being able to anticipate, intercept and execute a smooth, controlled, minimum energy glide slope with full flaps and full brakes is a basic skill every XC pilot should have in his toolbox.

I practice this at every opportunity and encourage my advancing XC students and flying buddies to do the same.

best,
Evan Ludeman / T8

[[email protected]]

Less spoilers near touchdown should cause a lower sink rate and lower the chance of a bad attitude tail strike breaking something.

But doing the last half of final aiming for the end of the runway with a small spoiler setting puts you in a low energy situation. With a long runway, this could be fixed by moving the aim point down the runway and expecting the student to get there.

As far as training is concerned, I wonder if this might miss the goal of landing with the right sight picture, right touchdown attitude, in a short field, or over a tree line. That seems a lot of forced relearning later in trade for saving the trainer.

Maybe this isn't the right trainer to use first to teach landing?

[Richard McLean[_2_]]

On Thursday, 24 May 2018 08:50:42 UTC+8, wrote:
> Less spoilers near touchdown should cause a lower sink rate and lower the chance of a bad attitude tail strike breaking something.
>
> But doing the last half of final aiming for the end of the runway with a small spoiler setting puts you in a low energy situation. With a long runway, this could be fixed by moving the aim point down the runway and expecting the student to get there.
>
> As far as training is concerned, I wonder if this might miss the goal of landing with the right sight picture, right touchdown attitude, in a short field, or over a tree line. That seems a lot of forced relearning later in trade for saving the trainer.
>
> Maybe this isn't the right trainer to use first to teach landing?

We teach initial landings in the ASK21 & now the DG-1001 (nosewheel version) which has replaced the SZD-50 Puchacz. Here in Oz we teach "1/2 to 2/3 airbrake on final" .. the problems only come into play when the student mishandles the approach & overshoots, then corrects by pulling full brake & consequently over-rotating ... all I'm suggesting is that in this specific scenario we limit the amount of airbrake used to help avoid the over-rotation & instead accept the overshoot. The DG is fine otherwise, it just lands a little hot as described in the previous posts, and it has a heavy tail.