Dominion 2-HW ,a Self-Righting Foiling RC Keelboat/ One-off Design & Build Project - Page 3 - RC Groups
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Sep 28, 2015, 08:59 PM
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Dick L.'s Avatar
@Tom
Not providing anything related to credibility, Tom.

Only was pointing out that "MANY" ideas have a track record of having been around for - oh- at least a couple of decades. Both of the boats referenced, along with the P Cat (Pacific cat) and some from the UK and down under all had solid platforms between two symmetrical hulls, usually (not always) of a round cross section. Photo is of a Shark, semi-circular cross hull sections joined together by a solid (folding) platform.




http://www.boatdesign.net/gallery/sh...php/photo/3631
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Sep 28, 2015, 09:12 PM
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Dick L.'s Avatar
@Doug - not sure how many scows you have down there in Florida, but here in the upper Midwest (Minnesota, Wisconsin and Michigan) we have an ample supply, and I have yet to see any M20's up here with tunnel hulls.

To be fair, I don't usually frequent scow competition.
Sep 28, 2015, 09:35 PM
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DLord's Avatar

M 20 Tunnel Hull


Dick-the M 20(not MC-20-M20 has a jib)) is famous for its tunnel hull. We have lots of scows in Florida particularly on Lake Eustis. When I was a kid I got to crew on an E scow-which was just extraordinary.
On the M20/I20 the tunnel is not all that big-about 3" but on Dominion it was much bigger. If I do this on the model , it would be more like Dominion than the M 20 in order to reduce wetted surface to the maximum.
M20 history:

http://m20-scow.com/history.html

"The M-20 must be considered an advanced scow design and will remain so for years to come. Its high aspect sail plan is similar to the America's Cup Technology currently in use today, and provides a wide range of controls for all wind conditions. The tunneled hull of the M-20 is her most unique feature and provides increased stability and structural stiffness."
Last edited by DLord; Jan 26, 2016 at 09:32 PM.
Sep 28, 2015, 09:41 PM
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I20 Tunnel Hull


The I20 was "born" from the M20-both have tunnel hulls:
http://scowsailing.com/about/

"The I-20 is the most recent scow class, adapted from the tunnel-hulled M-20 scow designed in 1963 by Harry and Buddy Melges."
Last edited by DLord; Sep 29, 2015 at 09:57 AM.
Sep 29, 2015, 02:43 PM
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Foiling RC Keelboat Scow


I decided to go with a tunnel hull based more on Dominion* than the M20. Cross structure has good clearance when on foils and boat will look like a scow. * See previous page
Length to beam ratio on 1/2 the boat(one "hull") will be close to 13/1. Rather than design the "hulls" like a cat they are specific to this boat and are designed to support half the weight at static. A cat doubles displacement on a single hull when the windward hull flies. Some cats are designed for this. When this boat heels it will be generating lots of lift from the foils and shouldn't need extra buoyancy.
I did a lot of calculations showing that the wetted surface of the "Dominion" type hull is about 30% less than a "normal" scow hull and the resistance is lower due to the high L/B ratio. Ideal for an RC scow.....
CHANGE:--dropped the transom .156"(5/32") to reduce rocker. Boat has a movable ballast system which can be used to raise the transom in very light air.

click for larger:
Last edited by DLord; Oct 09, 2015 at 02:34 PM.
Sep 29, 2015, 03:24 PM
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Dick L.'s Avatar
Doug -

believe it or not, there ARE some of us watching and waiting for your original foiler to be presented in an accomplished fashion with results showing it actually will sail on foils ... for a decent distance. Of course, then there is the modified Formula48 that was supposed to be tested and video provided. But now you are on to yet another project yet to be realized.

One thing at a time, man !!! Was easy to get lost in all of your theoretical postings.

As they say on the SA Forum - -----"Pics or it didn't happen"!
Sep 29, 2015, 03:29 PM
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DLord's Avatar
I might as well do this when I can't sail. When the weather cools down I can sail the cat, but I need help with video for both boats and help launching the Fire Arrow. Both boats have been modified and are ready to sail-just sitting here. Sooner or later-no rush.......see post 19.
The original foiler is the F3 and you personally witnessed it foil "in an accomplished fashion".

Some jackasses on SA say even with pictures and video it didn't happen!



Last edited by DLord; Sep 29, 2015 at 08:16 PM.
Sep 29, 2015, 05:50 PM
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Dick L.'s Avatar
Quote:
Originally Posted by DLord
Some jackasses on SA say even with pictures and video it didn't happen!
Hmmm - do you suppose they know "something"? Those no good, dirty
bds !
Sep 29, 2015, 07:16 PM
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You know if you throw a pig into the air, a still picture of that pig falling back to earth isn't evidence that pigs can fly no matter how many times you post it.....
Sep 29, 2015, 08:37 PM
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Dick L.'s Avatar
@Tom - Gotta remember that one !
Sep 29, 2015, 08:50 PM
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DLord's Avatar
You liked that, huh, Dick?!
Sep 29, 2015, 09:49 PM
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Dick L.'s Avatar
Yeah, mainly cause the photo of the boat with one foil in and one out looked a lot like one from quite a while back. Was wondering - seeing that it was edited, if it was a recycled version? Decided not to waste time by going back to look, so benefit of the doubt it is one from a collection of still photos.
Sep 30, 2015, 12:36 PM
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Foiling RC Keelboat Scow


Quote:
Originally Posted by DLord
Thanks ,Wolfgang! I think I'm going to build a one off model-this is a natural for an RC foiler model.
Tentative specs:
LOA 50"(1.2m)(changed 11/24/15-LOA 52"-see post 105)
Beam about 13.5"(.34m)CHANGE: Beam 14.25"
Weight, including fixed and movable ballast: 7lb
Sail Area: 1400 sq.in(.9sq.m)-reefable
Foils: 2 @13"(330mm) X 2.25"(57mm) + rudder foil
Features:
a.100% self-righting
b. Trapeze Power Ballast System
c. target to foil in 5mph breeze
-----
Lots and lots of potential thanks to the work Hugh Welbourn has done!
====================
Changed the beam but so far that's it. More later.

Pictures-L to R- 1) Dominion the original tunnel hulled scow, 2) Dominions sectional shape, 3) "Super Scow"- my original tunnel hulled scow with a Trapeze Power Ballast System, 4) Q 23.
The tunnel on the "Super Scow" was more like the M20 than Dominion-fairly shallow. The new hull is much more similar to Dominion under water. Of course, the most important aspect of the new boat is the foils which will get the hull clear of the water in around a 5 mph wind:
Last edited by DLord; Nov 25, 2015 at 03:54 PM.
Sep 30, 2015, 05:20 PM
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Foiling RC Keelboat Scow


I've done the Simpsons calcs:
1) Displacement 8.6lbCHANGE: 8.22lb(both-target all up sailing weight 7lb)
--
2) Lb. per 3/32" immersion=.78lb(both)Change: per 1/8th inch: 1.18lb(both)
--
3) Prismatic 59%CHANGE: 55%
----------------------------
Will have to study this and check the sections at the waterline and a couple of diagonals:





Last edited by DLord; Oct 24, 2015 at 10:05 AM.
Sep 30, 2015, 10:27 PM
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DLord's Avatar

Foiling RC Keelboat Scow


Some things I'm looking at now:
1)While the "Dominion" version of this scow has around 30% less wetted surface than the "normal" version, the Dominion version has about 30% more skin area above the waterline on the underside of the hull.
--
2) Since the boat is using lifting foils it should heel with no increase in displacement(or wetted surface) on the lee hull in the lightest breeze and foil at about a 9.5-13 degree angle of heel.
--
3) Initial stability is high with the Dominion version but sail area is about the same as a Mini 40 and total weight should be around 8.5-9.5lbs(target 9). The movable ballast system will be important in light or heavy air.
--
Last edited by DLord; Feb 13, 2016 at 01:59 PM.


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