Laser 161752 Tynemouth |
![]() |
Laser 140101 Tynemouth |
![]() |
Laser 28 - Excellent example of this great design Hamble le rice |
![]() |
List classes of boat for sale |
Mast Head T Foil? |
Post Reply ![]() |
Page 123 5> |
Author | |
iGRF ![]() Really should get out more ![]() ![]() Joined: 07 Mar 11 Location: Hythe Online Status: Offline Posts: 6499 |
![]() ![]() ![]() ![]() Posted: 29 Oct 14 at 9:49am |
So, I alluded to it in banter over on the kicker attachment thread, but it's been an idea I've been toying with, initially as a cure for turning turtle but with the secondary consideration of a power boost by converting tip turbulence to power generating flow at the head of the sail. Obviously it would only function with fathead sails, but what do the hive mind think?
Could such a thing be beneficial to the point main sail size reduction might even be possible? How such a thing could be constructed, I'd suggest kite technology from kite surfing, so a bow leading edge secured with a central batten down the middle of the foil so it is two sided the central batten attaching to the top or top batten of the sail. The result would be a wing tip foil closing the head. With the spin off of course of a mast head float. Thoughts? Edited by iGRF - 29 Oct 14 at 9:50am |
|
![]() |
|
iiitick ![]() Far too distracted from work ![]() Joined: 04 Jun 14 Location: gb Online Status: Offline Posts: 478 |
![]() ![]() ![]() ![]() |
I thought we discussed this topic a while back?
|
|
![]() |
|
iGRF ![]() Really should get out more ![]() ![]() Joined: 07 Mar 11 Location: Hythe Online Status: Offline Posts: 6499 |
![]() ![]() ![]() ![]() |
Oh no did we already?
Nurse! I need some more of those memory tablets.. |
|
![]() |
|
iiitick ![]() Far too distracted from work ![]() Joined: 04 Jun 14 Location: gb Online Status: Offline Posts: 478 |
![]() ![]() ![]() ![]() |
It was a long time ago when you and I were much younger....and Holman minor was still in short trousers.
|
|
![]() |
|
Chris 249 ![]() Really should get out more ![]() ![]() Joined: 10 May 04 Online Status: Offline Posts: 2041 |
![]() ![]() ![]() ![]() |
It doesn't work; aerodynamics 101. You are better off using the same weight, area and complication to increase the mast height.
This has been pointed out repeatedly since the 1980s by big boat designers. It's also been repeatedly pointed out on Boat Design Forum by MIT aero professor Mark Drela (designer of world champion human powered boats and aircraft and AC winning multis) and Tom Speer (Boeing and Oracle AC designer).
|
|
![]() |
|
Medway Maniac ![]() Really should get out more ![]() ![]() Joined: 13 May 05 Location: United Kingdom Online Status: Offline Posts: 2788 |
![]() ![]() ![]() ![]() |
Well, aircraft use winglets to recover some energy from the tip vortex instead of just adding span, and they are less concerned about the bending moment at the wing root than we are about the heeling moment, so I'm surprised that the great and good have ruled it out on sails.
I'd be interested to read their reasoning. Do you have any useful links, Chris?
|
|
![]() |
|
MattHarris ![]() Groupie ![]() ![]() Joined: 03 Oct 06 Location: United Kingdom Online Status: Offline Posts: 94 |
![]() ![]() ![]() ![]() |
I thought it was used on aircraft as they are restricted by space in airports where the wings can only have a maximum width.
|
|
![]() |
|
maxibuddah ![]() Really should get out more ![]() ![]() Joined: 06 Mar 09 Location: United Kingdom Online Status: Offline Posts: 1760 |
![]() ![]() ![]() ![]() |
By stopping the airflow from falling off of the end of the wing because of the fin it increases the amount of lift for a given wing size. That enables the carriers to carry less fuel, saving money
|
|
Everything I say is my opinion, honest
|
|
![]() |
|
iGRF ![]() Really should get out more ![]() ![]() Joined: 07 Mar 11 Location: Hythe Online Status: Offline Posts: 6499 |
![]() ![]() ![]() ![]() |
Increasing the mast height as well as adding weight it adds leverage and heeling moment, so if the mast height could be reduced, or if a boat already has a given mast size, but the addition of a light foil up top which could tidy up the vortices up there and probably add area for downwind running and reaching due to the resulting upward swing as the boat heels, I'd like to see empirical evidence of it having been tried before writing it off.
|
|
![]() |
|
Rupert ![]() Really should get out more ![]() Joined: 11 Aug 04 Location: Whitefriars sc Online Status: Offline Posts: 8956 |
![]() ![]() ![]() ![]() |
It could well work better than a float bouncing around at the top of the mast, a pad in the top of the sail or a flying saucer thing up there.
|
|
Firefly 2324, Puffin 229, Minisail 3446 Mirror 70686
|
|
![]() |
Post Reply ![]() |
Page 123 5> |
Forum Jump | Forum Permissions ![]() You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |