The 40 Degree Flap Question

twotter · Post by **twotter** » Sat Mar 17, 2007 2:47 am

By the way, I just don't get the problem with using the flaps that are available and the airplane was certified to use..

Over the past few years, I see more people using climb flaps when taking off with a beaver and using take off when landing. Do you think DeHavilland was stupid?? Why do you think they call it take off flap?? Or landing flap for that matter. Why would you want to take off or land at a higher speed than you need to?? Other than a severely gusty X wind, I always use them for taking off or landing.. That is the way the airplane was designed.. As for the twin otter, I will sometimes only use 30 if it's a gusty x wind (25+) or glassy water but other than that it is the full 37 1/2.. Sometimes, I've even been known to use the dreaded 30 for t/o. For those of you in a cessna, they put 40 on it for a reason.. Think about it..

I just don't get why people are scared to use their flaps.. They are there to help you.

Idriveplane · Post by **Idriveplane** » Sat Mar 17, 2007 5:30 am

You think it's 1700 feet? I'm sure it's gotta be shorter than that... 1500?We should go out there and pace it someday we're bored

Edit: I stand corrected - it's 1800 on Google Earth this year, last year and the year before 1500 & 1600 or so. Seems awfully short eh? I don't recall if you were around last year but it is a good 10 feet wider this year.

I took my car out one night and measured it and thats what it came out to (very roughy). Agreed though, can be a lil short if one comes in hot. I love the braking action we have now after those warm days

I can't even get the tails (185 and found)to pivot over when having to turn around. Good thing its 10 feet wider this year, the more the merrier.[/quote]

Driving Rain · Post by **Driving Rain** » Sat Mar 17, 2007 5:40 am

The Stone Boat Co. of Rat Portage Ontario.. now Kenora. Where the seaplane docks are now situated was where they built them. The Kenora pilots started calling the otter the Stone Boat and it stuck for some reason.

Hoov · Post by **Hoov** » Sun Mar 18, 2007 1:42 am

I thought 40 degrees was just there cuase the designers were bored though. Obviously they had no idea what they were doin, just really loaded off of cheap beer.

Rudder Bug · Post by **Rudder Bug** » Sun Mar 18, 2007 7:48 am

This accident report speaks volumes about the use of flaps with a Beaver

http://www.tsb.gc.ca/en/reports/air/200 ... 4c0098.asp

Tui · Post by **Tui** » Sun Mar 18, 2007 8:17 am

You mean the incorrect use of flaps in a Beaver. I was there for that and know the guy who checked him out. Very unfortunate. Something they don't mention much is the operations poor aircraft loading habits. (Resulting in the need for full nose down trim.)

Rudder Bug · Post by **Rudder Bug** » Sun Mar 18, 2007 8:21 am

I totally agree Tui

Cat Driver · Post by **Cat Driver** » Sun Mar 18, 2007 8:39 am

It is ingenuous to suggest that there is any inherrent danger in flying any certified aircraft within its design limits and using the flaps for the purpose they were designed.

Incorrect loading, incorrect airspeed control or incorrect attitude for said airspeed is not the fault of the design.

Airplanes do not crash themselves, pilots crash airplanes.

PT6-114A · Post by **PT6-114A** » Sun Mar 18, 2007 8:55 am

I got docked on a flight test once I was asked to do a "normal landing" and used full flap on a 150 and got told I was doing and emergency landing and had to do it again.

just curious · Post by **just curious** » Sun Mar 18, 2007 9:02 am

My machine only goes to 37 1/2. What a gyp!

Rudder Bug · Post by **Rudder Bug** » Sun Mar 18, 2007 9:12 am

I got docked on a flight test once I was asked to do a "normal landing" and used full flap on a 150 and got told I was doing and emergency landing and had to do it again.

That guy was an examiner???

Cat Driver · Post by **Cat Driver** » Sun Mar 18, 2007 9:12 am

" My machine only goes to 37 1/2. What a gyp! "

Aaahhh, but can you handle it?

Edo · Post by **Edo** » Sun Mar 18, 2007 9:22 am

This is what I tell pilots on a checkout:

Whatever flap setting you normally land in that's the one to use in an engine failure. I think that if you normally land with 30 degrees adding 40 when the engine quits, is a bad idea. The approach attitude is already different enough when gliding, no need to add an unusual flap setting in as well.

The full flap power off landing, is encouraged whenever possible. Ideally I want to see full flap approaches with the power coming off just before the flare (do not carry power into the flare to smooth the TD)

In the Beaver, I start by using just a bit more than t/o flap for landing, then slowly increase the amount of flap to the landing mark. For normal ops I use just slightly less than landing flap, (better aileron control) and landing flap when needed.

I think the worst thing you can do in a Beaver is lose the engine and try gliding in with full flaps.

In any other airplane full flaps unless its really gusty.

Comments ?

Falken · Post by **Falken** » Sun Mar 18, 2007 11:13 am

There's no point on quoting any single person, since there are many who are talking about 'people being afraid of flaps' and about 'the designers not being stupid' etc.

I don't think anyone is afraid of using flaps. When used in inappropriate situations they can produce problems: ie full flaps in gusty x-wind conditions in the cessnas, full flaps at gross on larger aircraft, ect. Some of those can be more dangerous than others, mostly depending on ones experience.

The idea that they were designed in and thus are inherantly always safe to use doesnt make sense. Obviously the Cessna engineering team is not made up of idiots, but they don't expect the pilots to be idiots either. It's akin to saying that the engine primer was designed into the plane, so it must be a good idea to use it as much as / whenver you like... but we all know different amounts are required for different conditions and should only be used at different times.

Sure, full flaps are a tool that's there to help you fly the plane. Just like emergeny power, alternate air, or the electric engine starter. Use them to make your flying easier, better, and safer.. at the right times, in the right conditions.

boozy · Post by **boozy** » Sun Mar 18, 2007 11:33 am

Flaps on the beaver I found to be tricky to get used to I guess. I suppose in less than two months we'll all be back at er, so now's a good time to start thinking about it again. My memory is horrible so I think this is how I was doing it:

On Normal landing, powereded back some maybe 20-25 inches, when the speed came around 85-90 (I think 85-90), I just slowly added flaps a few pumps at a time. The amount all depending on the lake and my desire to descend. Sometimes I'd just give a pump or two. Generally in the last 100-200 feet, I'd bring the flaps to take-off or a little more than that. And thats it.

If I remember correct here, with take-off flap on a not-so-gusty day you could approach at 60 knots (if you feel like it...various factors and what-have-you), and land the beaver in in swimming pool and still need to step taxi to the other side.

I rarely used landing flaps because I just didn't need to. But I'd have no trouble using them. As for Full flaps, used them twice ever on landing and that was two more times then I needed too. I just ran out of elevator and got lucky that my float tips were up.

Anyhoo...crucify me if you must...

PT6-114A · Post by **PT6-114A** » Sun Mar 18, 2007 12:48 pm

That guy was an examiner???

Yip it was in 1998 at ZBB just as you walk in the door hang a left. Takled to a lot of people about it after and got a lot of answers.

My instructor's at the time were guys with about 25 000+ hours on all kinds of stuff (old bush guys)
PT6

xsbank · Post by **xsbank** » Sun Mar 18, 2007 2:08 pm

I think I've confused 'landing' with 'full' flaps. The last notch of flap in a Beav is not supposed to be used on floats, but you can (unless its in the limitations) under the right circumstances.

That is all.

YACdirect · Post by **YACdirect** » Sun Mar 18, 2007 4:52 pm

xsbank I don't think whether the aircraft is on floats or wheels or anything else for that matter will affect the limitation imposed by DH: "the use of FULL flap is only required for emergency landing in very restricted areas" which is what is says in the AFM. It makes no destinction between the landing gear configuration.

"There is nothing wrong with full flap landings.. Thats what full flap was designed for."

Well that depends on what airplane you are talking about. As mentioned, the DHC2 is not designed for full flap landings except in exceptional circumstances - i.e.: not a nice happy return to your three-mile-long lake of a base. The 206 is limited to 30 degrees, and I believe the old 172's with 40 flap were limited to 30 when on floats as well.

As for the guy who claimed the use of 40 flap was incorrect for a normal landing on a flight test, I would have knocked him in the head with the POH, opened to the page with the landing checklist itemizing: "FLAPS..... as required"

As for Full flaps, used them twice ever on landing and that was two more times then I needed too. I just ran out of elevator and got lucky that my float tips were up.

I have heard of a couple who weren't so lucky...

Cat Driver · Post by **Cat Driver** » Sun Mar 18, 2007 5:15 pm

For those of you who have difficulty figuring out how and when to use different flap settings here is the answer.

http://i43.photobucket.com/albums/e353/ ... f4e977.jpg

Problem solved, you will never have to worry about what flap setting to use.

hotspur666 · Post by **hotspur666** » Sun Mar 18, 2007 9:14 pm

The Walter Otter, full flaps...35 knots and
IT STILL FLOAT AWAY!!!
A touch of reverse make it plop down just where you want.

(We're talking with the Barron leading edge here.)

However, careful of crosswinds...

Still, no commercial airplane can fly as slow as the Walter Otter.

Rudder Bug · Post by **Rudder Bug** » Sun Mar 18, 2007 9:25 pm

Hotspurr,

Trevor had the right flap setting. A tree buted a strut and he lost a wing. We thouhgt the main cause was the absense of a tail ski and wet snow, which streched his takeoff to the point where he had a split second to take a vital decision. He took the wrong one.

hotspur666 · Post by **hotspur666** » Sun Mar 18, 2007 9:26 pm

Could somebody explain to me THAT accident?
http://aviation-safety.net/database/rec ... 20031216-0
First, how can you operate an Otter on skis without tailwheel skiis???
If you dont need skiis on the fragile tailwheel, you dont need skis at all!

And how can someone NOT takeoff an Otter on a 3200feet runway?
You only need 500 feet, no wind.

Maybe they did NOT have the Barron mod...

hotspur666 · Post by **hotspur666** » Sun Mar 18, 2007 9:30 pm

True enough, most of our take off where with a tailwhind,
but on a river with unlimited distance.
On a runway, better watch the wind closely with wet snow.

But lots of operators remove the tailskis.
A torn tail would cost in the high tens of thousands!

Rudder Bug · Post by **Rudder Bug** » Sun Mar 18, 2007 9:56 pm

Hello Hotspurr,

I also operate without a tail ski these days. The snow is so hard that the tailwheel does its job. We have lots of ice patches and more use the wheels/brakes than the straight skis.

I once broke a tail ski an a long takeoff with a stoneboat in rough hard snow. It swrilled around so bad and poked big holes in the lower fuselage side.

hotspur666 · Post by **hotspur666** » Sun Mar 18, 2007 10:20 pm

Spring'll be there soon...

Better put the skis back!

This is where you beat the Caravans, they wouldn't dare
go on that rotten ice...with skis, you float over the holes...

The 40 Degree Flap Question

DHC-2 and use of full flaps

Flaps beaver