Flaps VS Airbrakes/Spoilers

Well about half of the posts re flaps only gliders made me feel positive about the possibility of finding a glider with flaps only, and the other half made me feel just the opposite. I guess you could dump flaps on final rather quickly if your speed was above stall for all ranges of the flaps as they came up but the purpose of flaps is to create more lift allowing for a lower approach speed or am I mistaken? Apparently beyond a certain point the flaps cease to provide lift and are only a drag device. It would make sense that a quick move from the drag area back to the maximum deflection for lift could be accomplished quickly with little problem.

I guess the best option is for a glider with both flaps and spoilers/airbrakes but I don't think there are a lot of those out there. Sometimes too many opinions from too many people are a bad thing.

Walt

On Aug 15, 2:57*pm, Walt Connelly Walt.Connelly.
wrote:
Well about half of the posts re flaps only gliders made me feel positive
about the possibility of finding a glider with flaps only, and the other
half made me feel just the opposite. *I guess you could dump flaps on
final rather quickly if your speed was above stall for all ranges of the
flaps as they came up but the purpose of flaps is to create more lift
allowing for a lower approach speed or am I mistaken? *Apparently beyond
a certain point the flaps cease to provide lift and are only a drag
device. *It would make sense that a quick move from the drag area back
to the maximum deflection for lift could be accomplished quickly with
little problem.

I guess the best option is for a glider with both flaps and
spoilers/airbrakes but I don't think there are a lot of those out there.
Sometimes too many opinions from too many people are a bad thing.

Walt

--
Walt Connelly

Check out the Mini Nimbus, Mosquito and early Ventus.

On 8/15/2011 2:57 PM, Walt Connelly wrote:
Well about half of the posts re flaps only gliders made me feel positive
about the possibility of finding a glider with flaps only, and the other
half made me feel just the opposite. I guess you could dump flaps on
final rather quickly if your speed was above stall for all ranges of the
flaps as they came up but the purpose of flaps is to create more lift
allowing for a lower approach speed or am I mistaken?

The 'purpose of flaps' - Is this where philosophy enters the aerodynamic world
definable by flaps' effect on a glider's polar? To me, viewed most generally,
the purpose of (large deflection landing) flaps is identical to the purpose of
spoilers, i.e. to ease Joe Glider Pilot's task of safely making a landing
pattern into 'glider-size' fields...different ways to skin the ease/safety cat.

Beyond that, both options come with their pros & cons. Again to my way of
thinking, it would be a 'glider shame' to wantonly disregard/not use the
flap-related effect of increasing the max lift inherent in the use of the
simply-hinged flaps used on (say) every 15-meter FAI-class ship around and
most 15-meter span ships. That's true even if the ship uses its flaps 'only'
for optimizing the drag bucket of the airfoil in cruise (i.e. they don't
deflect much beyond ~20-degrees). Stated another way, if Joe Glider Pilot's
ship has (small deflection, 'intended for cruise optimization-only') flaps, in
conjunction with intended-for-landing spoilers, why *wouldn't* JGP go to max
positive deflection flaps before then using spoilers for primary glidepath
control? He still would (could) obtain a theoretical lower touchdown speed
benefit contrasted to not using the flaps.

Where I'm headed with this is, one can reasonably conclude the 'purpose of
flaps' is whatever JGP decides, within their aerodynamic capabilities. You've
noted above, one possible purpose...and others have (and probably will again!)
note this particular purpose comes with its own safety-based 'recommended user
guidelines!' In other words, there's nothing about having (only) large
deflection landing flaps that *insists* one make the whole approach below the
flaps-off stalling speed. I generally did so only under absolutely benign
conditions, otherwise until 'somewhere around' flare altitude keeping my speed
at or above the flaps-off stall speed, less from fear of 'falling out of the
sky like a brick' should I (for whatever reason) instantaneously dump the
flaps, and more because it simply provides a larger margin (margins being good
in my book). However, in any pattern conditions that I thought safely
permitted, I also sought to minimize my touchdown speed (whether on or off
airport) by *using* the extra lift inherent with flaps to minimize my
*touchdown* speed...easiest on the the equipment, if nothing else.

Apparently beyond
a certain point the flaps cease to provide lift and are only a drag
device.

"Roger that...and folks will probably 'O-beer-thirty' argue if that point is
30-degrees, 45-degrees, or more." Pick whatever number you like for now!

It would make sense that a quick move from the drag area back
to the maximum deflection for lift could be accomplished quickly with
little problem.

....and beyond, if you have the height margin and hand-eye skills...


I guess the best option is for a glider with both flaps and
spoilers/airbrakes but I don't think there are a lot of those out there.

Only the AS W-20A in the large deflection w. spoiler field that I know of, but
lotsa designs with small-deflection flaps with spoilers. And, of course, the
'don't fit precisely into either category' ships like Mosquito, Vega, Mini
Nimbii, early Ventii, etc., which have their own devils in their own details!
Such fun!!!

Sometimes too many opinions from too many people are a bad thing.

Heh!

Regards,
Bob W.

On 8/15/2011 1:57 PM, Walt Connelly wrote:

I guess the best option is for a glider with both flaps and
spoilers/airbrakes but I don't think there are a lot of those out there.
Sometimes too many opinions from too many people are a bad thing.

There are lots and lots of them out there! Starting with the ASW 20, all
Schleicher flapped gliders have had "high deflection" landing flaps and
spoilers. ASW 20, ASW 22, ASH 25, ASH 26, ASW 27, ASG 29, and so on.

"High deflection" ranged from 40 degrees to 60 degrees. None of them had
full deflection flaps.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

On Aug 15, 4:57*pm, Walt Connelly Walt.Connelly.
wrote:
Well about half of the posts re flaps only gliders made me feel positive
about the possibility of finding a glider with flaps only, and the other
half made me feel just the opposite. *I guess you could dump flaps on
final rather quickly if your speed was above stall for all ranges of the
flaps as they came up but the purpose of flaps is to create more lift
allowing for a lower approach speed or am I mistaken? *Apparently beyond
a certain point the flaps cease to provide lift and are only a drag
device. *It would make sense that a quick move from the drag area back
to the maximum deflection for lift could be accomplished quickly with
little problem.

I guess the best option is for a glider with both flaps and
spoilers/airbrakes but I don't think there are a lot of those out there.
Sometimes too many opinions from too many people are a bad thing.

Walt

--
Walt Connelly

Landing flaps are quite effective in many ships and really effective
in a few.
Really effective examples: HP series, Concept 70, PIK 20- all are
flaps only
In these ships, you usually don't put full flap in till you have the
field made with margin. Then, if high, just put the nose down a bit
more and down they come. Because they are so effective, there is
rarely any reason to raise them again because you are plenty high.
Flare needs to be soon enough to begin to bleed speed a bit before
going into ground effect to reduce floating down the airport.
I once landed my PIK-20 in a football field over the goal post.
Most effective: ASW-20 early before B and C. Flaps plus spoilers.
Steep approach, no speed build up , min float in flare. I landed my 20
over the goal post and stopped with lots to spare.
"Not quite like 20"- 20B and C, ASH-26, ASW-27, ASG-29. Excellent, but
go around the goal post .
Really effective- 1-35. Around the goal post
Others- The Glasflugel and SH gliders with trailing edge flap brakes
also come down quite well. One benefit is that they are intuitive to
use and easy to transition into.
There is no reason to be afraid of flaps only ship. That said, you
must get some good prep and training to learn how to do it right and
that does NOT come from RAS posts. There is a lot of bad info that is
hard to weed out.
FWIW
UH

On Aug 15, 2:57*pm, Walt Connelly Walt.Connelly.
wrote:
Well about half of the posts re flaps only gliders made me feel positive
about the possibility of finding a glider with flaps only, and the other
half made me feel just the opposite. *I guess you could dump flaps on
final rather quickly if your speed was above stall for all ranges of the
flaps as they came up but the purpose of flaps is to create more lift
allowing for a lower approach speed or am I mistaken? *Apparently beyond
a certain point the flaps cease to provide lift and are only a drag
device. *It would make sense that a quick move from the drag area back
to the maximum deflection for lift could be accomplished quickly with
little problem.

I guess the best option is for a glider with both flaps and
spoilers/airbrakes but I don't think there are a lot of those out there.
Sometimes too many opinions from too many people are a bad thing.

Walt

--
Walt Connelly

I have been flying a Laister LP-15 Nugget for about three years now
and I love the glider as well as the flap system. On the Nugget, the
flaps are super simple, working more like spoilers in terms of
function. One caution on flapped ships is that some are too complex
and make things tougher while landing. I'm sure that once a pilot is
dialed into what ever he or she is flying it becomes second nature
though.

Get a Kestrel and have both... (and a drag chute for good measure)

On 2011/08/16 3:00 PM, Blake Seese wrote:
On Aug 15, 2:57 pm, Walt ConnellyWalt.Connelly.
wrote:
Well about half of the posts re flaps only gliders made me feel positive
about the possibility of finding a glider with flaps only, and the other
half made me feel just the opposite. I guess you could dump flaps on
final rather quickly if your speed was above stall for all ranges of the
flaps as they came up but the purpose of flaps is to create more lift
allowing for a lower approach speed or am I mistaken? Apparently beyond
a certain point the flaps cease to provide lift and are only a drag
device. It would make sense that a quick move from the drag area back
to the maximum deflection for lift could be accomplished quickly with
little problem.

I guess the best option is for a glider with both flaps and
spoilers/airbrakes but I don't think there are a lot of those out there.
Sometimes too many opinions from too many people are a bad thing.

Walt

--
Walt Connelly

I have been flying a Laister LP-15 Nugget for about three years now
and I love the glider as well as the flap system. On the Nugget, the
flaps are super simple, working more like spoilers in terms of
function. One caution on flapped ships is that some are too complex
and make things tougher while landing. I'm sure that once a pilot is
dialed into what ever he or she is flying it becomes second nature
though.

--
Bruce Greeff
T59D #1771 & Std Cirrus #57

On Aug 16, 8:51*am, wrote:

There is no reason to be afraid of flaps only ship. That said, you
must get some good prep and training to learn how to do it right and
that does NOT come from RAS posts. There is a lot of bad info that is
hard to weed out.
FWIW
UH

Agreed. On RAS even the normally sane, competent, always-within-his-
limits UH starts telling stories of landing over and between goal
posts.

:-).

-T8

Here are a few links that can be used as guides to flying flaps-only ships.
http://www.soaridaho.com/Schreder/Large-span_flaps.html
http://www.soaridaho.com/Schreder/St..._HP_flight.htm
http://www.soaridaho.com/Schreder/St...r_on_Flaps.htm
http://www.soaridaho.com/Schreder/HP...st_Flight.html

I know this is more information then you really want to know. Sorry about
that!

Wayne
HP-14 "6F"
http://tinyurl.com/N990-6F



"T8" wrote in message
...

On Aug 16, 8:51 am, wrote:

There is no reason to be afraid of flaps only ship. That said, you
must get some good prep and training to learn how to do it right and
that does NOT come from RAS posts. There is a lot of bad info that is
hard to weed out.
FWIW
UH

Agreed. On RAS even the normally sane, competent, always-within-his-
limits UH starts telling stories of landing over and between goal
posts.

:-).

-T8

On Aug 15, 4:57*pm, Walt Connelly Walt.Connelly.
wrote:
Well about half of the posts re flaps only gliders made me feel positive
about the possibility of finding a glider with flaps only, and the other
half made me feel just the opposite. *I guess you could dump flaps on
final rather quickly if your speed was above stall for all ranges of the
flaps as they came up but the purpose of flaps is to create more lift
allowing for a lower approach speed or am I mistaken? *Apparently beyond
a certain point the flaps cease to provide lift and are only a drag
device. *It would make sense that a quick move from the drag area back
to the maximum deflection for lift could be accomplished quickly with
little problem.

I guess the best option is for a glider with both flaps and
spoilers/airbrakes but I don't think there are a lot of those out there.
Sometimes too many opinions from too many people are a bad thing.

Walt

--
Walt Connelly

My personal favorite get the glider down right now device is a drogue
chute. My Open Cirrus had one in the bottom of the rudder, and the
one time I really needed it on a landout, it worked like a charm. I
practiced with it once and deployed it from 800 FT over the numbers at
SPA, the glider was on the ground and stopped between the vasi's. You
have to put the nose over rather smartly to keep the chute from
pulling the glider into a stall, but man it brings it down in a hurry.

The Open Cirrus I used to own is up for sale again, so for a nominal
fee, you too can have a drouge chute equiped glider.


SF