RE: Fowler Flaps
 

Did you notice the price on those Robart Fowler tracks ? 75 bucks for 4 !

Seems like Hobby Lobby had an aluminum track set in the past. Real nice looking. I can't find them now. And they were driven by a worm drive mechanism. Sweet setup.

There have been a few articles in the past on building the Fowler tracks. Looks complex and it looks like they could jam easily if not built correctly. And nobody is building multi-segmented fowlers that I can tell.


Hey Flyboy, what did that RVSM altitude cost on the Westwind ? I have heard some absurd numbers.

RE: Fowler Flaps
 

Whatever you call the flaps on the Cessna high wing types, the "simulated fowler" flaps in the Top Flite Skylane kit do not replicate the movement of their full scale counterparts properly while the Robart "fowler flap" hinges do! Besides, the "simulated" kit-designed setup looks ugly and out of place on what's supposed to be a scale plane[:'(]

RE: Fowler Flaps
 

There is a simple way to build simulated Fowler Flaps, afterall we are only building models not overweight scale aircraft. On my 80" H9 Piper Cub I used round pin hinges (Robart) install them on the bottom of the wing as in robarts how to hinge flaps, they do move slightly aft , Then downwards. I attached a strip of lexan to the top front of the flap which slides in and out of the wing to fill air gap, bingo your done. and they will slow the piper down so slow at landing there is hardly any roll out. Come on dont argue just share your ideas.

RE: Fowler Flaps
 

There is a fowler hinge (looks kinda like it might simulate):
http://www.hobby-lobby.com/balllink.htm

RCStore has 3 sets of plans for fowler flaps
http://www.rcstore.com/rs/general/li...d=33&catego=PL

Here is what I've been thinking of for a P-38 with fowlers.

RE: Fowler Flaps
 

What about Fairey - Youngman flaps? Like on the Fairy Firefly or the Westland Wyvern
Do these flaps fall in one of these categories of flaps?


Regard
RCer

RE: Fowler Flaps
 

Don't quote me, but I'd guess they might fall into the slotted flap family.

RE: Fowler Flaps
 

Four types of flaps. You will see them on various aircraft. Often Slotted flaps are confused for Fowler type flaps. Split flaps often do move to the rear as deployed, but the length of movement is only sufficient to create a slot. This improves lifts by allow air from under the wing to travel through the slot and over the surface boundry layer on the top of the flap which increase lift dramatically over standard (plain) or split. I addition to flaps, there are a host of high lift devices for the leading edge such as droops, slats, and slotted slats.

RE: Fowler Flaps
 

wat kinde of flaps have the 336 skymaster???
[sm=confused.gif][sm=wink.gif]

RE: Fowler Flaps
 

Good pic of full scale Fowler flaps on an ATR.

RE: Fowler Flaps
 

Hi Marc,
Don't know if this will interest you, but there is a P38 kit out there that has true Fowler flaps as standard and as I understand it, it's ARTF!!
These links should do it...

This one is a comparison of the VQ ARTF kit with the KMP kit

http://www.rcwarbirds.com/twinmanpage.htm

And this one is the VQ homepage... it includes video of the operating Fowler flaps

http://www.vqmodelaircraft.com/produ...craft/p38.html

Hope you enjoy!
cheers
Sheds

RE: Fowler Flaps
 

At the risk of beating a dead horse in the pursuit of accuracy, the "fowler" designation means that on extension
the flap moves aft, then down via a track, drive screw or external hinge, increasing wing chord, wing area and altering the chordline of the wing.

A fowler flap may have one, two, three or more segments. The B-737 and B-727 for instance have a multiple segment, multi slotted fowler flap
driven by internal jackscrews (hydraulic, I believe), while all single engine Cessnas since the C-150 have a single slotted fowler flap driven by an
electric motor that ride in a track similar to those sold by Robart website: http://robart.com/Hinge.aspx

Review of the following pics will show that both Boeing jets and single engine Cessas have fowler flaps, differing only in their size and complexity...

B-727:

http://www.airliners.net/open.file?i...=918272&size=L


Single Engine Cessnas:

http://www.airliners.net/open.file?i...=958272&size=L

http://www.airliners.net/open.file?i...=948044&size=L

Cheers!

Jim

C.A.R.F. has a P47 out right now that includes working fowler flaps. Go check it out they are cool as **** .If I could afford one I would certainly buy one but I cannot afford to fly C.A.R.F. airplanes but if I could I certainly would so to those of you who can my hats off to you and I am jealous as **** of your airplane....lol

Most high-wing Cessnas have Fowler flaps, 172's, 182's, 336/337 and a bunch of others that share the same basic wing. I built a L-19 from Roy Vaillancourt plans about 15 years ago which had them. The plans only allowed for 40 degrees, but I modified them to allow the full 60 degrees the full scale Bird Dog had. I sold the plane before finishing it, one of my big regrets.
https://cimg9.ibsrv.net/gimg/www.rcu...96b1d95435.jpg
https://cimg9.ibsrv.net/gimg/www.rcu...e371ef59fc.jpg
https://cimg0.ibsrv.net/gimg/www.rcu...77333bfc92.jpg
https://cimg1.ibsrv.net/gimg/www.rcu...d3f68d23da.jpg
https://cimg4.ibsrv.net/gimg/www.rcu...e28fad74fa.jpg
Full scale:
https://cimg8.ibsrv.net/gimg/www.rcu...9bbac02d14.jpg
https://cimg8.ibsrv.net/gimg/www.rcu...2e4ce1499e.jpg

Those are not Fowler flaps, they are Slotted flaps.
The Fowler flaps combine very significant aft movement to increase wing area, with downward movement to increase camber.

Since such a mechanism is far more expensive to produce, with a questionable advantage for light aircraft, they are rather non cost effective which is probably the reason we usually see them only on heavy transport aircraft or very specialized STOL aircraft.

I think Robart used to sell a mechanism for making Fowler flaps on models.

The only requirement for a Fowler flap is to move rearward as it moves down. Fowlers increase the effective chord as they increase camber. They can simply pivot or they can slide. The ones on Cessnas pivot for simplicity and do create a slot and are called slotted fowler flaps. The slot allows airflow to pass through and over the flap's top surface to decrease turbulence and drag along the trailing edge, improving lift. In the case of the Bird Dog, they could lower a maximum of 60 degrees and significantly improve STOL performance on landing. If you note the picture above showing the full flap position, the forward edge of the corrugated surface is flush with the top of the wing when flaps are fully retracted, which shows how far back they have come as they drop. Up to 30 degrees can be used for takeoff. Note how little runway is behind this one as it takes off, which I have had the opportunity to ride in. It has no other specialized STOL devices that you see on a lot of bush planes.
https://cimg9.ibsrv.net/gimg/www.rcu...a158f6dc8a.jpg

Here’s a Link to the Robart Fowler flap hinges I mentioned.
As can be seen, they allow the surface to slide back while deflecting downward.

As to the Bird Dog, I believe the early versions had Slotted flaps that deflected 60 degrees, while later versions had Semi-Fowler flaps that deflected 40 degrees.

My reference on the L-19/0-1 does not mention a change in maximum flap extension nor a design change, except from manual to electric operation. It states :
A single, slotted Fowler high-lift flap is installed at the trailing edge of each wing. The flaps are controlled by a hand lever and cable-operated bellcrank, and push-pull tube mechanism. Most L-19's have been converted to electric flap operation, which provides any angle of flap desired from 0 degrees to 60 degrees. Maximum angle of extension is 60 degrees, with intermediate positions on the manual system of 30 and 45 degrees.
It also describes the materials used and the motor location for the electric flaps. The wing never changed on any of the L-19/0-1 variants. The conversion to electric flaps occurred around 1953 after the accident rate increased in the type. Investigations showed that most were during the landing phase when pilots were engaging flaps manually which took a free hand from the controls and made them shift position for leverage to operate the handle, which took some effort. Historically, Bird Dogs flew with manual flaps for a much shorter period than they did after the conversion to electric.

My resource is "The Lovable One-Niner", a definitive reference on the L-19/0-1.

I guess I confused between the Bird Dog and the 170 where to my understanding at some point Cessna reduced the angle of flap deflection.

This Operating Manual clearly refers to the Bird Dog flaps as single slotted flaps (page 19) and if you study their hinging/operating mechanism, they definitely are such.

I won't argue the point, I have references that call them slotted Fowlers. They do move rearward as they drop down. The Bird Dog wing is the same as the 170 wing, basically the A model L-19 is a tandem-seat C170 with more glass and some redesign for the narrower cockpit and windows. I suppose it may have been a specific criteria for the military to have flaps that extended further for short field operations. Later variants got a bigger engine and constant-speed prop but the airframe stayed the same. Gross weight did increase and affected flight performance a little, such as an increase in stall speed.