with the center ridge on one side of the blade?
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|Messages in this Topic|
It's not a GP at all|
Posted by: mintjulep on Sep-18-12 3:15 PM (EST)
Sounds like an Aleutian Island style paddle.
Posted by: Peter-CA on Sep-18-12 3:16 PM (EST)
The one with the ridge is an Aleutian style, based on the region where the paddles were often used. GP means Greenland Paddle, and is based on the paddles used traditionally in Greenland.
Thanks. I knew I was wrong but also|
Posted by: string on Sep-18-12 3:35 PM (EST)
knew I would get the correct answer.
Aleut, GP, symmetry, dihedral|
Posted by: gstamer on Sep-18-12 6:12 PM (EST)
You are probably talking about an Aleut paddle as has been pointed out. That said, some Greenland paddles also feature a pronounced diamond shape on both paddle faces that results in a sharp peak down the center (on both sides of the blade).
Aleut and a joy!|
Posted by: bartc on Sep-18-12 7:39 PM (EST)
I researched this well before building my own Aleut paddle out of Western Red Cedar. This paddle is a joy to use, easy on my body, very efficient (particularly in any wind), great for distance, and can do anything you need it to do well. It's also a conversation starter everywhere!
I love my GP|
Posted by: rpg51 on Sep-18-12 7:51 PM (EST)
I purchased a Greenland Paddle last winter and it has been a true joy. Mine is a Lumpy. Very nice workmanship. Fits me like a glove.
the Aleutian Solution|
Posted by: RavenWing on Sep-18-12 8:01 PM (EST)
is working for me!
If it's made out of wood|
Posted by: magooch on Sep-20-12 3:56 PM (EST)
I call it a stick. I build my own, but I haven't built one yet that gets used as much as my Euros.
call it whatever you want.|
Posted by: RavenWing on Sep-22-12 5:25 PM (EST)
I don't care. There is a difference betw. greenland and Aleutian paddles, and a wide variation within both types.
Wow, very interesting. Questions.|
Posted by: Glenn_MacGrady on Sep-20-12 4:09 PM (EST)
Live and learn on pnet. I had never heard of or seen such a paddle before.
I Asked That Very Question|
Posted by: Kudzu on Sep-20-12 4:30 PM (EST)
in a thread a while back. The answer I got was that the ridge prevented flutter. Since my GPs don't flutter it's not the paddle for me.
I was making wood chips before |
Posted by: string on Sep-20-12 4:50 PM (EST)
I started paddling and I think they look cool, so .....
What is the power face?|
Posted by: Glenn_MacGrady on Sep-20-12 4:51 PM (EST)
If the ridged side is supposed to be the power face, that sharp ridge seems to be a rather primitive and overly aggressive means of preventing flutter via what we (somewhat confusingly) today call camber or dihedral. My first assumption was that the ridged side was the back face.
Posted by: carldelo on Sep-20-12 5:15 PM (EST)
The function of the ridge is to anchor the stagnation line on the paddle face, or at least keep it from wandering too far. Flutter can be interpreted as oscillation of the stagnation line, causing flow to preferentially spill over one side of the blade, then the other, in rapid succession. The resulting pressure fluctuations on the blade cause the paddle to wobble side to side.
It's the flutter thing.|
Posted by: bartc on Sep-20-12 5:16 PM (EST)
That's the purpose of the ridge and it works well to stop any flutter, which can be a problem if you don't cant a GP.
Trust doesn't work|
Posted by: Glenn_MacGrady on Sep-20-12 5:31 PM (EST)
I do trust the ability of ancient paddlers, but I don't necessarily trust us to understand what it is they intended. I'm still not convinced the ridge isn't a cambered back face.
There's plenty of info|
Posted by: carldelo on Sep-20-12 6:28 PM (EST)
If you want reports on the behavior of Aleut and GP in various scenarios, you can start reading over at qajaqusa.org, there's a wealth of info there, most of it very well reasoned and perceptive.
Posted by: Glenn_MacGrady on Sep-20-12 8:10 PM (EST)
Carl, I'm initially inclined to disagree with some of the general assertions in your post -- re designs not competing, multiple engineering solutions (at least concerning paddles), and stagnation lines -- but I agree that I should do more research on Aleut paddles.
Concept vs actuality|
Posted by: carldelo on Sep-20-12 10:54 PM (EST)
The stagnation line is not a concept, it is a fact of 3-D fluid flow over an object. It marks the boundary between the flow that goes over one side of the object, vs flow that goes over the other side.
Concepts are reality|
Posted by: Glenn_MacGrady on Sep-21-12 5:55 PM (EST)
Of course there are stagnation points in 3D flows. Otherwise there couldn't be a Kutta condition on an airplane wing.
Posted by: carldelo on Sep-22-12 12:16 AM (EST)
Sorry but there is not a stagnation 'point' in 3D flow. A cross-section of 3D flow will show a point, but overall on the paddle itself, it is a line. The shifting of the stagnation line you describe is exactly the behavior that causes flutter. I think we're talking about the same phenomenon, and having a misunderstanding re: terminology, which is understandable for internet discourse. We should really be standing at the blackboard (with a beer?), and all this would be a lot more productive.
One last 11 dimensional point|
Posted by: Glenn_MacGrady on Sep-22-12 3:12 AM (EST)
Because I don't think we'll ever be together at a blackboard and I haven't drunk a beer since the Reagan administration. Sad as it is, the internet is my only current university.
Posted by: carldelo on Sep-22-12 11:56 AM (EST)
Someone Handed Me One|
Posted by: Kudzu on Sep-20-12 6:34 PM (EST)
Posted by: redmond on Sep-20-12 6:56 PM (EST)
A man's wife would always cut off the end of a roast before cooking it. When he asked her why she did this, she said that her grandmother was a wonderful cook and that's what she always did.
The garbage theory of the Aleut ridge|
Posted by: Glenn_MacGrady on Sep-20-12 8:40 PM (EST)
Here's a theory similar to grandma's roast.
Ask a simple question (that was simply|
Posted by: string on Sep-20-12 11:01 PM (EST)
answered) and you get a p.nut pissing contest! Maybe those Greenlanders weren't skilled enough to put ridges on their paddles.
Hey, that feels pretty good |
Posted by: mintjulep on Sep-21-12 6:38 PM (EST)
I think that neither the ancient Aleutian islanders nor the Greenlanders had a strong theoretical knowledge of fluid mechanics or access to nice laminar flow test tanks.
Posted by: rpg51 on Sep-21-12 6:45 PM (EST)
Getting way technical|
Posted by: MORiverPaddler on Sep-21-12 8:34 PM (EST)
Interesting history, but getting way out there!
Maybe Greenlanders didn't have any|
Posted by: string on Sep-21-12 10:42 PM (EST)
material to waste.
I've Got it!|
Posted by: Kudzu on Sep-22-12 6:54 AM (EST)
Posted by: sternman on Sep-22-12 6:58 AM (EST)
It's 6:50 in the morning. I just read this whole thread and now I'm ready for a beer.
I know, I know...|
Posted by: carldelo on Sep-22-12 12:08 PM (EST)
I hear you and get your point. But my field is fluid mechanics, and there is no such thing as 'over-analyzing' an issue like this, it's what I do. I certainly understand those who want to ignore all the technical talk - many (most?) of my students feel the same way.
Posted by: Fadedred on Sep-22-12 12:45 PM (EST)
you must also factor in that the paddle doesn't just come straight back, it is also piercing or traveling out from the kayak. this would relieve the tip from a vortex that is caused from shedding the flow.....the actual water shedding will be away from the tip.
Engineers and over analyzing..|
Posted by: sternman on Sep-22-12 2:05 PM (EST)
I've got a few Engineers as friends and they drive me crazy. No worries since I'm used to it. ;-]
Quaqte from an old manager:|
Posted by: string on Sep-22-12 2:39 PM (EST)
"There comes a time in the life of every project when you need to shoot the engineer and move on."
Posted by: Kudzu on Sep-22-12 3:25 PM (EST)
If it ain't broke
Posted by: ret603 on Sep-23-12 11:43 AM (EST)
Posted by: kayamedic on Sep-23-12 6:25 PM (EST)
I did a fairly leisurely paddle of five miles in an hour with your Aleut paddle. Ridge pointing back.
Don't pick on engineers. Other thoughts.|
Posted by: Glenn_MacGrady on Sep-23-12 4:17 PM (EST)
reflections on Glen's post|
Posted by: ret603 on Sep-23-12 7:45 PM (EST)
Re. the attributes in Glen's point 1 and point 2--- I see no reason to separate them and think they act together synergistically. That's my opinion, not based on any experiments.
The ridge is on my paddle to be and |
Posted by: string on Sep-23-12 8:00 PM (EST)
it ain't coming off.
Skinboat School. Bantam. Canoe.|
Posted by: Glenn_MacGrady on Sep-23-12 8:58 PM (EST)
Dave, where is the Skinboat School you keep mentioning? I visited a place up around Anacortes Island in 1999 or 2000, where a guy had a school to build baidarkas. I got all interested and bought Dyson's book. Almost bought a baidarka at the Wilton Outdoor Center.
Posted by: ret603 on Sep-24-12 10:46 AM (EST)
Posted by: mintjulep on Sep-24-12 9:27 AM (EST)
I set out to make an effort to try the non-ridged face of my Aleut paddle as the power face.
wrong language used|
Posted by: ret603 on Sep-24-12 10:25 AM (EST)