Reply
 
Thread Tools Search this Thread
 
Old 10 August 2017, 14:50   #1
Member
 
Roflhat's Avatar
 
Country: UK - Scotland
Town: Isle of Lewis
Boat name: Macleod Special
Make: Ceasar Thundercat
Length: 4m +
Engine: Yamaha 70ces
Join Date: Jul 2010
Posts: 865
RIBase
Thundercat Rear Wing

Looking for ideas for what to use as a rear wing on my thundercat, thinking something like a yacht rudder or something similar, needs to be as lightweight as possible but strong. Was thinking yacht rudder as the profile is about right for a foil, but need something bigger really
__________________

__________________
Roflhat is offline   Reply With Quote
Old 10 August 2017, 14:56   #2
Member
 
fel2's Avatar
 
Country: Canada
Town: Québec
Length: 3m +
Join Date: Dec 2016
Posts: 59
Click image for larger version

Name:	IMG_0143.JPG
Views:	107
Size:	20.8 KB
ID:	121330
__________________

__________________
fel2 is offline   Reply With Quote
Old 10 August 2017, 15:24   #3
Member
 
Country: UK - England
Town: penzance
Boat name: not named
Make: ski boat
Length: 5m +
Engine: 150 HPDI
Join Date: Sep 2013
Posts: 224
That's outrageous - who in their right mind would paint the spolier red when the car is such a lovely pink?

Never seen a thundercat with a wing. What's the goal? Aerofoil or water foil?
__________________
simonl is offline   Reply With Quote
Old 10 August 2017, 15:49   #4
Member
 
Roflhat's Avatar
 
Country: UK - Scotland
Town: Isle of Lewis
Boat name: Macleod Special
Make: Ceasar Thundercat
Length: 4m +
Engine: Yamaha 70ces
Join Date: Jul 2010
Posts: 865
RIBase
Quote:
Originally Posted by fel2 View Post
haha, pretty much!

Quote:
Originally Posted by simonl View Post
That's outrageous - who in their right mind would paint the spolier red when the car is such a lovely pink?

Never seen a thundercat with a wing. What's the goal? Aerofoil or water foil?
No neither have I, but in my mind it should work. As long as it doesn't create too much drag and it's not too heavy. Thinking an aerofoil

The problem with going faster in a thundercat is that it becomes very unstable, as less and less hull is in contact with the water. The entire hull acts as a wing, with the lifting surface ahead of the centre of gravity, which is right at the back where the engine is. So as the boat starts to lift (going to flip) there is no moment counteracting that. Adding a large rear wing with 0 angle of attack whilst travelling at normal speed and angle would then act as a counter moment, which could stop the boat flipping over backwards.

My idea is to put a large rear wing far behind the transom, so as the boat starts to lift the air hitting the wing would then push the bow back down.
__________________
Roflhat is offline   Reply With Quote
Old 10 August 2017, 16:01   #5
Member
 
fel2's Avatar
 
Country: Canada
Town: Québec
Length: 3m +
Join Date: Dec 2016
Posts: 59
Thundercat Rear Wing

Keep in mind it would need to be adjustable because of wind condition

Well, it's not like you enjoy going out with 100 mph front wind. After all

A-frame with a wing just under the top wouldn't look too strange.
__________________
fel2 is offline   Reply With Quote
Old 10 August 2017, 16:13   #6
Member
 
Country: UK - England
Town: penzance
Boat name: not named
Make: ski boat
Length: 5m +
Engine: 150 HPDI
Join Date: Sep 2013
Posts: 224
I think it'll be a struggle. Some thoughts - As the front lifts there's a large hull wing as you say. Once this lifts it increases in frontal area hugely.
Upward force = say 1 sq.m 3m from c.o.g. 1 x 3 = 3

To counteract this at a point 1m from the c.o.g
3 x 1 = 3
you'd need 3m2 to equal the upward lift, plus it would have to be at least at the same angle as the front, plus it would be shadowed by the front so you might need to double it! We're now at the size of a good windsurfer sail!
If it's not about winning races, maybe work out a way to stuff a 'water brake' at the back as the nose rises. that'd pull the bow down sharpish. It could be done automatically, but it's a harsh environment. Another way would be to use a small wing at the front. This could use radio control technology to keep a perfect trim. Not too difficult... except for the environment again.


edit: pessimistic post by me. Anything you do will be interesting & something to learn. Keep us posted
__________________
simonl is offline   Reply With Quote
Old 10 August 2017, 16:16   #7
Member
 
fel2's Avatar
 
Country: Canada
Town: Québec
Length: 3m +
Join Date: Dec 2016
Posts: 59
Then Click image for larger version

Name:	IMG_0144.JPG
Views:	75
Size:	24.9 KB
ID:	121331
__________________
fel2 is offline   Reply With Quote
Old 10 August 2017, 16:16   #8
Member
 
fel2's Avatar
 
Country: Canada
Town: Québec
Length: 3m +
Join Date: Dec 2016
Posts: 59
If you need
More great idea let me know !
__________________
fel2 is offline   Reply With Quote
Old 10 August 2017, 16:19   #9
Member
 
Country: UK - England
Town: penzance
Boat name: not named
Make: ski boat
Length: 5m +
Engine: 150 HPDI
Join Date: Sep 2013
Posts: 224
Quote:
Originally Posted by fel2 View Post
Comes with free keyring
__________________
simonl is offline   Reply With Quote
Old 10 August 2017, 17:04   #10
Member
 
Roflhat's Avatar
 
Country: UK - Scotland
Town: Isle of Lewis
Boat name: Macleod Special
Make: Ceasar Thundercat
Length: 4m +
Engine: Yamaha 70ces
Join Date: Jul 2010
Posts: 865
RIBase
thanks Felix, good inspiration

I had thought about how large the wing would have to be, I was thinking of a long wide wing, wider than the hull so it would be running in clean air. Was also thinking it could be mounted a couple meters back, using lightweight tubing as framing to mount it.

Had also considered an active front wing, but that would require some sort of automatic actuation which is going to be difficult and require electrical power
__________________

__________________
Roflhat is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 07:41.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.