Attn: Libelle 201 pilots
James Locke
my 201's energy on touchdown.
I've received some interesting ideas in general and some real insight
from a 301 Libelle pilot in particular. He mentioned that he flies his
approach at 45kts (about 52mph). I've been coming in at 60mph in no
wind or gentle breeze conditions.
I have been told to fly approaches (in no wind) at a speed 50% above the
glider's stalling speed. That rule-of-thumb would put my Libelle's
approach, for my weight, at 60mph as stall is 41mph. (As a side note,
I've also been told that the minimum approach speed should equal
one-third faster than stall speed).
The 201 manual suggests 50mph for approach. That seems slow to me. To
follow the manual and come in at only 9mph above stall just seems too
slow--and that's without taking into account the increase in stall speed
with the brakes out.
What do you other 201 pilots use as your approach speed on no-wind
days? Why?
Jim Locke
Libelle 201B, SN 158
N254X, 4X
(remove NOSPAM to reply directly)
Jonathan Gogan
The dragonfly is so achingly beautiful that
I fail to understand the need to land?
Reminder: As you know well:
With the brakes out, a small reduction in speed
will reduce the energy and shorten the approach
- Make wider circuits. especially longer base legs,
crabbing outwards before final if required.
- 1/2 to 3/4 brakes : I don't like relying on full brakes
as you then have no 'spare'
(apart from sideslip: Wheeeeeeeeeheeeee: FullOppositeRudder)
- Like they say 20% above minsink so for a craft that flys
minsink ~ 42 knots your nill wind approach is just under 50
And with a bit of breeze upto 55
Sound about right for you Glasflugel slippybubble ?
Alternatively: Buy a tail parachute ?
JiN
Martin Spieck
>
> [...]
> - Like they say 20% above minsink so for a craft that flys
> minsink ~ 42 knots your nill wind approach is just under 50
Just curious: Why do you take minsink as a reference?
Seck
Tom Wilschut
have quite some experience with my st Libelle coming in slow and make short
landings. You specificly need this kind of landing technique/experience if
you go cross country flying and even more when flying in the mountains,
where the outlanding posibilities are rare and if you find a landing strip
it is going to be small. What is important is your ground speed, and the
wind direction. With little wind you usually don't have a lot of turbulence
and it should not be a problem to come in at the adviced landing airspeed of
50/53 mile or 80/85 km( you don't want much groundspeed now). It is advised
in your manual to use half brakes when coming in, this is advised to give
you the possibilty to correct your appraoch angle if you are short (close
your brakes) and encrease the appraoch angle when coming in to high (open
your brakes completly). But landing with full brakes out is not a problem.
If you are not fermiliar with landing with full brakes, you should practice
this, untill you know how to do this fluently. Another way to get confidence
flying your Libelle at 50 miles airspeed and full brakes, is doing this at
some altitude. You will find out how your Libelle reacts and when it will
stall. My experience is that the Libelle drops like a stone at 50/53 miles
80/85 km airspeed and is all the time easy to handle. With some wind you
have less problems and you can come in at higher speed, which problably you
have been taught with a two seater. Your groundspeed will be reduced because
of the windspeed and so is less important. Landing at 50 miles 80 km's
airspeed with high winds is not smart, mainly because of the turbulence you
get when appraoching (trees, buildings etc) the ground (turbulence means,
that the wind speed is not consistant it may vary 3 to 8 miles and makes
you drop out of the sky when you haven't got enough airspeed). So when
landing with high winds it is adivised to fly at least 10 miles or 15 km's
(airspeed) faster the last 150 feet/ 80 m. Flying cross country and landing
out with a lot of wind and not knowing what the wind direction is will put
you in problems especially if your choice of landingstrip is a short one!!
Your brakes are most effective at 50/53 miles 80/85 km's ""airspeed"" (at no
wind or at high wind), flying faster makes them less effective (help = high
energy landing problem) so you better get used to flying your Libelle by the
book. It is not a K 13, Janus, Lsx etc with "doors" to encrease drag and
spoil the wings. Your Libelle is a real plastic plane, you don't fly it like
we did with Grunau Baby's, Prefects and those lovely old timers!!!
Have fun and safe landings!!!
Tom Wilschut
t....@consunet.nl
James Locke heeft geschreven in bericht
<35D91329...@NOSPAMknova.com>...
Kempton Izuno
Echoing what others have said:
- Learn to slip effectively without building up speed
- Full airbrakes on final/roundout is fine. All my landings is with
full brakes.
- Speed control is paramount
We fly our 201B in high elevation areas (5,000ft +) so higher approach
speeds are required to handle the greater wind shear, stronger gusts,
and longer vertical recovery distances. A severe case is at Truckee
(California) at 5,900ft. with typically a 15 - 40kph crosswind.
Anything less than 100kph on final in those conditions is asking for
trouble. I carry the speed until flare then let it bleed off. After
6,000+ XC miles in our Libelle, EVERY landing is short field practice.
Have you checked your wheel brake system? I had my cable tightened up
and that can shorten a hard surface rollout by one third or more. If
that's not enough, clean up the dust buildup on the drum pads and
anything else that may reduce braking.
At a more strategic level, a personal policy is to always land at an
airport (and there aren't that many in Western Nevada!). It's easy on
the crew and gives you room. Only once have I landed off airport, and
that was on an excellent dirt road.
***The single greatest change I could wish for is if Streifeneder
provided a double panel airbrake mod just like what's available to Std.
Cirrus owners. Last year I checked with Streifeneder to see if there
was such a kit for Libelles, but no such luck. I would pay good money
to have such a mod., and it would address the biggest single issue with
Libelles, IMHO.
Kemp
---------------------
Fellow pilots:
I'm looking for some safe ways to get rid of some energy on landing. I
just got a 201 Libelle and, if I hold my approach speed throughout
final, float is rather long. I haven't tried full dive brakes on
landing; rather, I'm going for about half brakes upon touchdown. And
I've been reluctant to bleed off speed on final though I did scrub off
about 8mph (from 60mph down to about 52mph just before starting the
flair) on my last landing and that resulted in a shorter float and roll.
A friend and former Libelle pilot and fan told me that a 201 will force
you to make good approaches. I'm seeing his point. So, how do I make
excellent, well-grooved approaches and short landings?
Thanks in advance for any ideas and discussion.
Jim Locke
Jean-Marie Clément
James Locke wrote:
> I have been told to fly approaches (in no wind) at a speed 50% above the
> glider's stalling speed. .......................
>
> The 201 manual suggests 50mph for approach. That seems slow to me. To
> follow the manual and come in at only 9mph above stall just seems too
> slow--and that's without taking into account the increase in stall speed
> with the brakes out.
>
> What do you other 201 pilots use as your approach speed on no-wind
> days? Why?
>
> Jim Locke
> Libelle 201B, SN 158
> N254X, 4X
>
This rule of thumb, as you say, seems to be the rule in your country.
However, if you apply it, you will never be able to land correctly any FRG
heavy glider. Specially in outlandings, you will reach the end of the field
still flying!
The right speed is 1.25 Vs without wind in calm air and 1.3 Vs in case of
possible turbulence. All without airbrakes. If wind, add 1/2 of the wind
until 20 kt. Then, it is your feeling.
--
Jean-Marie Clément
Via delle Forze Armate, 26
I - 20147 Milano
Tel. +39-(0)2-4870 5377 Fax: +39-(0)2-4870 5352
Mobile +39-(0)335- 6049 302
Jonathan Gogan
Don't know really, some base their
thoughts on stall speed + some %
and some on minsink.
You want to be safe and minsink is higher ?
Jonathan
Martin Spieck
Well, if you want to be "safer" you could add some extra % to stall
speed...
It's not a big difference for most gliders, but for the ASW 24 (without
winglets) I remember the minsink-speed to be app. 95 km/h (51 kts - not
too sure if I'm right), and the stall speed at about 70 km/h (38 kts),
which would make quite a difference.
Nevertheless, all those "magic formulas" are, imho, only rough guides.
Important values of the sailplane like manoeuvring capabilities at low
speed or stall conditions are not (and can hardly be) taken into
account. It's up to the pilot to use his brain and to adapt the approach
speed to the specific characteristics of his glider (and, of course, the
situation).
Seck
(Martin "...but Vs+50% seems to be exaggerated" Spieck)
cul...@my-dejanews.com
James Locke <jlo...@knova.com> wrote:
> I started a thread re
> my libelle 201's energy on touchdown.
> I've been coming in at 60mph in no
> wind or gentle breeze conditions.>
Jim Locke, I saw your first landing in your newly acquired
Libelle about a month
ago at LaGrange Georgia.
It looked fine; landing was perfect.
It was a pleasure to be there
with you on that special day.
> The 201 manual suggests 50mph for approach. That seems slow to me>. To
Try for the book nrs several times, then adjust as indicated by
experience. But do so only after you are sure the book numbers
are not working the way you want it to.
Hope that by now your additional flights have sorted your questions
out into answers. What has been your conclusion? Can you fly by
the book?
Keep it up! Jim Culp USA cul...@hotmail.com
appropriate if they are not.
> Jim Locke
> Libelle 201B, SN 158
> N254X, 4X
>
> (remove NOSPAM to reply directly)
>
>
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JohnPegase
>Subject: Re: Attn: Libelle 201 pilots
>From: cul...@my-dejanews.com
>Date: Mon, 07 Sep 1998 23:10:43 GMT
>
>In article <35D91329...@NOSPAMknova.com>,
> James Locke <jlo...@knova.com> wrote:
>> I started a thread re
>> my libelle 201's energy on touchdown.
>> I've been coming in at 60mph in no
>> wind or gentle breeze conditions.>
>
>
WAY TOO FAST!
I had a Libelle fro four years and found it great fun out climbing everything
in the sky, and I'm sure you'll enjoy it too.
Landing speed for the Libelle is slower than most other glass gliders. In nil
wind to about 10 kts I approached at 50 kts. In stronger winds up to almost 20
kts 55 was adequate escept when gusty. I worked on the basis that if you
needed 60 kts it was too windy to fly! (Based on the standard formula of
normal flying speed plus half the wind speed.)
It is a bit disconcerting coming in at 50 kts as the nose seems a bit high
(just like in the Duo Discus in fact). If i couldn't see the landing area, i'd
roll very slightly to the left or right to check it was clear. I used to enjoy
converting friends to my glider, and the whole airfield would watch the fun as
they floated past the launch point to land 1-200 yds further on. Then they'd
sheepishly admit they had come in faster than advised. The airbrakes are set a
bit far back on the wing but are prefectly good enough - if you use the
recommended approach speeds. Otherwise you float on for ever because in the
round out they don't protrude enough into the airflow when you flair.
The guys who bought my Libelle had the same problem for a year as they refused
to believe the approach speeds I'd told they to use. Then they were given
strict orders on how to land it from a more experienced instructor, and by the
third or fourth attempt could put it down in a short distance.
How short can you get it it down with practise? In the first field I put the
libelle into I cleared a small tree and stopped 170 paces further on. I
usually managed to stop within 150 paces of the hedge in most field landings
without any effort, although on one rather frantic occasion (cows walked into
my prefered field as I pulled the airbrakes) I managed less than 100 paces (the
field was 120 paces!!) So how far past the boundary hedge do you come to a
stop?
John Wright, 742