Float plane question

[volant95]

OK guys, help me out here. My 9 year old son asked his ?flying god? father, me, what those ?things that look like little rudders on the tail (horizontal stab) are for?? We were looking at a Scout on floats. I know that many float planes have them and I?m sure they are for some kind of increased stability on water but I don?t know the specifics. Please, someone out there help me keep my ?flying god? status in my sons? eyes!

Thanks,

Jeff

[Crash]

The additional fins are requried on some aircraft models with certain float installations to help recover from spins and to make it harder to accidently get into a spin. I see a lot planes in Canada have them while the same set up here in Alaska dosn't have them. Crash

[Frank T]

They in effect increase the verticle fin area, and in doing so restore the loss of stability caused by the float installation.

[JP]

I always thought they were there to make Airnockers even uglier....

I saw several at Greenville yesterday and they were all being left behind by Super Cubs. :lol:

[CaptFox]

I was told that they are added as there is more surface area forward of the C of G on the floats than behind so the extra fins add to the cross sectional area behind the C of G to balance out any crosswind loads. I'm not an expert on it but it made sence to me.

David

[mvivion]

David,

You got most of it right, though it really has nothing to do with crosswinds, but as previously noted, it restores some of the inherant stability that the airplane lost as a result of the float installation. These may take the form of small fins on the ends of the stabilizer, or as a large ventral fin under the tail, as in the 206 and many Beavers.

Think of the airplane as a weathervane. Install more area ahead of the pivot point (the center of lift in this case) and it's not as stable a weather vane. Put a little more tail on it, and it's a better, more stable weather vane.

And, regards the comment about these devices making a Champ uglier, note that they are also installed on every Beaver, including the Turbine Beaver.

Try to buy a Super Cub for the price of a good old 7AC Champ, and then see how much performance you get.

There is little point in derogating someone else's pride and joy, all it does is make you smaller.

If it flys, it is a miracle, in my book, and I gotta love it.

Then again, I've met a few planes that were harder to love than others. but I learned to love them nonetheless.

Mike Vivion

[Torch]

Don't have them, don't need them. There is a beautiful Citabria on the east side of the pond at Fairbanks. Just been recovered. It looks good to me. Guy that owns it is a really nice guy. I do think the person above was just joking about Citabrias anyway.

Torch

[JP]

Whap! Whap! Spank! Spank!

The sound of meself being pelted by Champ pilots....so much for humour....

Really, I love them. In fact, I recently wept over the one at our seaplane base that dropped 20 feet onto the water....Ouch!

Anything that flies is indeed a miracle and miracles are sorely needed.

[Aviator]

Just a thought from the cobwebs; when Finnair started flying its new MD-11's (with winglets), we asked the inbound crew on Ground what those "things" were on his wingtips. Well, the poor bastard walked right into that one: He said they were "Little Finns."
8)

S.F.
Nick

[JP]

Having spent some very good times in HEL with my dear friends the Finns I can assure you that we all needed Little Finns ala the Scout to navigate our way back from the tango halls after an evening out....

Great people. They are nuts about civil aviation, too.

[mvivion]

JP,

Sorry, couldn't resist the smart a__ comment. Champs are pretty honest little critters, and great little floatplanes.

Unfortunately, the new ones have fallen to the fate of many newer generation airplanes, and that is they are HEAVY.

This, unfortunately, is the bane of many of our aircraft, and certainly impedes upward progress.

I was once told by an old time Cub mechanic, whilst I was debating what wingtips to put on my PA-12: "Son, it don't make any difference, to me, a wingtip is just a way to end a wing". Bob Mernan was his name.

Mike V

[StewartB]

Jeff,
You'll see the same added surface in the form of ventral fins on some C180's, and Husky's, and some others I can't remember. I always wondered why they just didn't add the surface as a bigger air rudder, which I think all floatplanes could use occasionally.
SB

[Aviator]

...Great people. They are nuts about civil aviation, too.

Don't get me wrong JP, I love them too (probably related to them from way back). This crew just happened to be a great "target of opportunity."

Nick

[Big AK]

Won't work, Stewart B!

A stabilizing vertical surface must be fixed to do its job. A larger rudder would not do the job of stabilizing the aircraft in yaw.

Note that the Wipline 2100 float installation on the PA-18 incorporates water rudders that center themsleves when retracted, and therefore center and "fix" the air rudder as well. Albeit the air rudder is 'fixed' through the water rudder steering cables with a spring inline.

Anyone flying a -12 or -14 without a centering device or ventral fin knows they wander a bit in yaw on floats. Nothing unflyable, but definitely more 'responsive' (touchy) in yaw.

[StewartB]

I'm no engineer, but when I put my feet on the rudder pedals, the rudder becomes fixed. Okay....... adjustable.
SB

[PA12driver]

All good advice, as for me I find that after thousands of hours I still tend to put my foot on the rudder in the same proportion that I turn my eyes to look where I want to go, if the tail don't follow I push da pedal a little mure? probably ain't in the flight manual but, hey my compass don't work either!

Tim

PS: My first solo way back when was in a 65hp champ on floats with that little thingy (anal fin) I still can feel the rush (60's word) when I finally got the other float to come unstuck from the river!

[bobnall]

Tim,

I got my first float time on Sunday with Tom Murphy. You said it best....What a rush!

Bob

[FlipFlop]

but, hey my compass don't work either! Tim

Letter of Investigation's in the mail...

[Cubus Maximus]

Just to let everyone know: The (25th annual) 2004 MN Seaplane Seminar / Convention will be held May 7-9th at Cragun's on Gull Lake in Brainerd, MN.

800-272-4867 for Cragun's Lodge reservations. Or there are numerous other resorts nearby (such as Maddens or Kavanaughs etc etc...).

You can land on Steamboat Bay and tie up to their mile long sand beach or if on wheels land across the road at the East Gull Lake Airport (9Y2 - 2618x160 - rnwy 13-31 - grass, unlighted, no fuel, bring your own tie downs, there's only 7 permanent anchors but plenty of parking area) and walk to the resort. Monitor 122.9 for the water and rnwy. There will be flight advisories from the ground (CAP types with handhelds) and docking help.

http://www.supercub.org/gallery/view_photo.php?set_albumName=cubs&id=ait

Steamboat Bay

http://www.supercub.org/gallery/view_photo.php?set_albumName=cubs&id=aip

Long final - rnwy 13 - East Gull Lake strip

http://www.supercub.org/gallery/view_photo.php?set_albumName=cubs&id=air

Short final - rnwy 13 - East Gull Lake strip

Or you can land at the main Brainerd Airport (BRD) and shuttle over. They have 3 active runways 5-23 / 12-30 / 1-19 with a 4th building. (fuel is: 91 octane MoGas / 100LL and JetA.) A large ramp with plenty of tie downs.

[T.J.]

Cuby, Sorry your to late. Tim faxed me a pic of the compass and I fixed it. Good job if I do say so. Less than 10 degrees off course.