Slats and Fowler Flaps On Light Plane

I feel there is a real advantage to the use of slats and flaps in
order to have things happen slowly during landing and yet still have a
good cruise speed. Of course the problem is in the complexity and the
extra weight. For rails I was thinking about something like standard
kitchen drawer rails or perhaps a tube within a tube design. I
wouldn't think their would be a lot of force on the slat at low
takeoff speeds so the structure wouldn't have to be bullet proof,
their would probably be a lot more force on the flaps though. I
haven't been able to find information if the necessary airplane
hardware is available commercially, perhaps it would have to be custom
made. Any ideas on how to go about building something like this?

Brock

On 25 Jul 2003 06:51:08 -0700, (Brock) wrote:

I feel there is a real advantage to the use of slats and flaps in
order to have things happen slowly during landing and yet still have a
good cruise speed. Of course the problem is in the complexity and the
extra weight. For rails I was thinking about something like standard
kitchen drawer rails or perhaps a tube within a tube design. I
wouldn't think their would be a lot of force on the slat at low
takeoff speeds so the structure wouldn't have to be bullet proof,
their would probably be a lot more force on the flaps though. I
haven't been able to find information if the necessary airplane
hardware is available commercially, perhaps it would have to be custom
made. Any ideas on how to go about building something like this?

Brock
+++++++++++++++++++++++++++++++++++++++

My FEELING is....
You can't safely get there from here.

Given the nature and level of your question....
perhaps you should look at aircraft designs
that you could copy or adapt to whatever
you have in mind.

Other than that, a degree in aero engineering might helpful
to bring you back to reality before someone is harmed.


Barnyard BOb -- stranger than fiction

"Brock" wrote in message
om...
I feel there is a real advantage to the use of slats and flaps in
order to have things happen slowly during landing and yet still have a
good cruise speed. Of course the problem is in the complexity and the
extra weight. For rails I was thinking about something like standard
kitchen drawer rails or perhaps a tube within a tube design. I
wouldn't think their would be a lot of force on the slat at low
takeoff speeds so the structure wouldn't have to be bullet proof,
their would probably be a lot more force on the flaps though. I
haven't been able to find information if the necessary airplane
hardware is available commercially, perhaps it would have to be custom
made. Any ideas on how to go about building something like this?

Brock

You could copy the flap design from the RV-10 or the Glasair series. Good
luck on the slats - those have to be built to very tight tolerances so they
operate at the same time. Differential slat extension has killed quite a few
people. Also, more than a few people have been killed by having a slat
depart the airframe in flight.

Vortex generators might be a safer alternative.

KB

Le Vendredi 25 Juillet 2003 18:50
Kyle Boatright a écrit:



You could copy the flap design from the RV-10 or the Glasair series.
Good luck on the slats - those have to be built to very tight
tolerances so they operate at the same time. Differential slat
extension has killed quite a few
people. Also, more than a few people have been killed by having a
slat depart the airframe in flight.

The slat MUST be built with mecanical link to operate together. See
what you can read about french design Morane Rallye ('60 to '80).
This plane had all the features you want.

By
--
Philippe Vessaire Ò¿Ó¬

Earlier, (Brock) wrote:

For rails I was thinking about
something like standard kitchen
drawer rails or perhaps a tube
within a tube design. I wouldn't
think their would be a lot of
force on the slat...

The two factors that might surprise you are the worst-case loads on an
extended slat at design limit loading, and the consequences of failure
of the actuators or the support rails. Taken together, they suggest
that the structure should be about as bulletproof as any other element
of primary structure.

...perhaps it would have to be
custom made.

Almost certainly the case. Fortunately, the raw materials (bearings,
steel, aluminum) are all relatively cheap and plentiful. Let the
Aircraft Spruce (or Wicks) catalog be your guide and playground.

Any ideas on how to go about
building something like this?

Make a sectional model out of garbage (plywood, masonite, nails) and
keep modifying it until it gives good motion.

Then make a prototype of one of the actuator/support stations, and
load test it to validate that it supports loadings about 1.5x of the
maximum expected.

Then make a full-scale prototype and test it on the experimental
aircraft of your choice. Good luck.

The slats on the Me-109 (or Bf-109) might be a god model to start
from. I understand that they're just spring-loaded so they pop out
when the pressure at the stagnation point goes below a certain value.

Thanks, and best regards to all

Bob K.
http://www.hpaircraft.com/hp-24

Brock wrote:

I feel there is a real advantage to the use of slats and flaps in
order to have things happen slowly during landing and yet still have a
good cruise speed. Of course the problem is in the complexity and the
extra weight. For rails I was thinking about something like standard
kitchen drawer rails or perhaps a tube within a tube design. I
wouldn't think their would be a lot of force on the slat at low
takeoff speeds so the structure wouldn't have to be bullet proof,
their would probably be a lot more force on the flaps though. I
haven't been able to find information if the necessary airplane
hardware is available commercially, perhaps it would have to be custom
made. Any ideas on how to go about building something like this?

Brock

Whereas the Helio Courier and Morane Rallye (among others), and their
slats, are discussed elsewhere in the thread; I'll just mention that all
of the high wing Cessna aircraft with which I am familiar have single
slotted Fowler flaps. I have no idea how much performance you would
gain with double slotted Fowler flaps, and doubt that they would add
much weight; but believe that they would be a real pain in the neck to
build s the dimensions would need to be held closely in order for the
slots to have the correct proportions and the additional surfaces would
need to be finished.

Peter

Steve Wittman had leading edge FLAPS (not slats) on his Buttercup.
Buttercup is a predecessor to the Wittman Tailwind.
That was back in the early '50s?

Anyway, the idea is to have a thin wing for high speed cruise and
recontour it into an undercambered thin wing to slow down for landing.

Thin airfoils tend to have low CLmax while recurred thin airfoils
can have amazingly high CLmax.

Taken to an extreme, the "sail" type single surfaced ultralight wings
show a CLmax of over 4(!)

Leading edge flaps are always(?) deployed in conjunction with trailing
edge flaps of some kind. Even if it is a simple split flap.

Otherwise, the CP would move way forward, and the chord line suddenly
goes the wrong way.

Earl Luce built the first replica Buttercup (and sells plans fo it too).

Earl said Buttercup lands in the low 40s with the flaps down.
Or over 70 (with a lot of skipping and skating) without them.

I did a little browsing at the NACA server and found a lot of info on
leading edge flaps. But it all seemed more applicable to supersonic and
high subsonic heavies.

To date, Buttercup is the only light plane I know of that has leading
edge flaps.

Richard


Peter Dohm wrote:

Brock wrote:

I feel there is a real advantage to the use of slats and flaps in
order to have things happen slowly during landing and yet still have a
good cruise speed. Of course the problem is in the complexity and the
extra weight. For rails I was thinking about something like standard
kitchen drawer rails or perhaps a tube within a tube design. I
wouldn't think their would be a lot of force on the slat at low
takeoff speeds so the structure wouldn't have to be bullet proof,
their would probably be a lot more force on the flaps though. I
haven't been able to find information if the necessary airplane
hardware is available commercially, perhaps it would have to be custom
made. Any ideas on how to go about building something like this?

Brock

Whereas the Helio Courier and Morane Rallye (among others), and their
slats, are discussed elsewhere in the thread; I'll just mention that all
of the high wing Cessna aircraft with which I am familiar have single
slotted Fowler flaps. I have no idea how much performance you would
gain with double slotted Fowler flaps, and doubt that they would add
much weight; but believe that they would be a real pain in the neck to
build s the dimensions would need to be held closely in order for the
slots to have the correct proportions and the additional surfaces would
need to be finished.

Peter

Many excellent points.

I started to write that I don't know of anything written regarding
leading edge flaps, either. Then decided to try a search on
http://www.dogpile.com/ and I found a reference when I tried flap
(singular) as part of the search argument in leading+edge+flap and got
"Aerodynamic loads on a leading-edge flap and a leading-edge slat on
the NACA 64A101 airfoil section" John A Kelly & George B McCullough
http://naca.larc.gov/reports/1954/na...ca-tn-3220.pdf

Unfortunately, I think you may need to know more about aerodynamics,
and some other things, to design anything really useful from it.
However, it appears intended to compare the characteristics of flaps
vs slats in in great detail; including graphs, sketched, and
tabulations of pressure distribution. And you and print it out.

Peter

By the way, the old Dover Edition of "Theory of Wing Sections" is
still available from various sources, and includes material on both
fixed and moveable slats alone and in combination with trailing
edge flaps. I don't recall whether leading edge flaps are also
discussed, and my copy seems to have hidden behind another book :-(

Richard Lamb wrote:

Steve Wittman had leading edge FLAPS (not slats) on his Buttercup.
Buttercup is a predecessor to the Wittman Tailwind.
That was back in the early '50s?

Anyway, the idea is to have a thin wing for high speed cruise and
recontour it into an undercambered thin wing to slow down for landing.

Thin airfoils tend to have low CLmax while recurred thin airfoils
can have amazingly high CLmax.

Taken to an extreme, the "sail" type single surfaced ultralight wings
show a CLmax of over 4(!)

Leading edge flaps are always(?) deployed in conjunction with trailing
edge flaps of some kind. Even if it is a simple split flap.

Otherwise, the CP would move way forward, and the chord line suddenly
goes the wrong way.

Earl Luce built the first replica Buttercup (and sells plans fo it too).

Earl said Buttercup lands in the low 40s with the flaps down.
Or over 70 (with a lot of skipping and skating) without them.

I did a little browsing at the NACA server and found a lot of info on
leading edge flaps. But it all seemed more applicable to supersonic and
high subsonic heavies.

To date, Buttercup is the only light plane I know of that has leading
edge flaps.

Richard

Peter Dohm wrote:

Brock wrote:

I feel there is a real advantage to the use of slats and flaps in
order to have things happen slowly during landing and yet still have a
good cruise speed. Of course the problem is in the complexity and the
extra weight. For rails I was thinking about something like standard
kitchen drawer rails or perhaps a tube within a tube design. I
wouldn't think their would be a lot of force on the slat at low
takeoff speeds so the structure wouldn't have to be bullet proof,
their would probably be a lot more force on the flaps though. I
haven't been able to find information if the necessary airplane
hardware is available commercially, perhaps it would have to be custom
made. Any ideas on how to go about building something like this?

Brock

Whereas the Helio Courier and Morane Rallye (among others), and their
slats, are discussed elsewhere in the thread; I'll just mention that all
of the high wing Cessna aircraft with which I am familiar have single
slotted Fowler flaps. I have no idea how much performance you would
gain with double slotted Fowler flaps, and doubt that they would add
much weight; but believe that they would be a real pain in the neck to
build s the dimensions would need to be held closely in order for the
slots to have the correct proportions and the additional surfaces would
need to be finished.

Peter

Oooops! I left NASA out of that URL and then forgot to test the
link in the message before I pressed send. The corrected version is:
"Aerodynamic loads on a leading-edge flap and a leading-edge slat on
the NACA 64A101 airfoil section" John A Kelly & George B McCullough
http://naca.larc.nasa.gov/reports/19...ca-tn-3220.pdf

Sorry about that.

Peter

The F-104 had both leading and trailing edge flaps and wing was
'blown'.

Big John
Mach 1+


On Sat, 26 Jul 2003 02:51:21 GMT, Richard Lamb
wrote:

Steve Wittman had leading edge FLAPS (not slats) on his Buttercup.
Buttercup is a predecessor to the Wittman Tailwind.
That was back in the early '50s?

Anyway, the idea is to have a thin wing for high speed cruise and
recontour it into an undercambered thin wing to slow down for landing.

Thin airfoils tend to have low CLmax while recurred thin airfoils
can have amazingly high CLmax.

Taken to an extreme, the "sail" type single surfaced ultralight wings
show a CLmax of over 4(!)

Leading edge flaps are always(?) deployed in conjunction with trailing
edge flaps of some kind. Even if it is a simple split flap.

Otherwise, the CP would move way forward, and the chord line suddenly
goes the wrong way.

Earl Luce built the first replica Buttercup (and sells plans fo it too).

Earl said Buttercup lands in the low 40s with the flaps down.
Or over 70 (with a lot of skipping and skating) without them.

I did a little browsing at the NACA server and found a lot of info on
leading edge flaps. But it all seemed more applicable to supersonic and
high subsonic heavies.

To date, Buttercup is the only light plane I know of that has leading
edge flaps.

Richard


Peter Dohm wrote:

Brock wrote:

I feel there is a real advantage to the use of slats and flaps in
order to have things happen slowly during landing and yet still have a
good cruise speed. Of course the problem is in the complexity and the
extra weight. For rails I was thinking about something like standard
kitchen drawer rails or perhaps a tube within a tube design. I
wouldn't think their would be a lot of force on the slat at low
takeoff speeds so the structure wouldn't have to be bullet proof,
their would probably be a lot more force on the flaps though. I
haven't been able to find information if the necessary airplane
hardware is available commercially, perhaps it would have to be custom
made. Any ideas on how to go about building something like this?

Brock

Whereas the Helio Courier and Morane Rallye (among others), and their
slats, are discussed elsewhere in the thread; I'll just mention that all
of the high wing Cessna aircraft with which I am familiar have single
slotted Fowler flaps. I have no idea how much performance you would
gain with double slotted Fowler flaps, and doubt that they would add
much weight; but believe that they would be a real pain in the neck to
build s the dimensions would need to be held closely in order for the
slots to have the correct proportions and the additional surfaces would
need to be finished.

Peter