My IOM scratch build... Vanquish - Page 11 - RC Groups
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Aug 30, 2008, 11:38 PM
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fin weightq


the fin core weighs 98 grams.
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Aug 31, 2008, 11:42 AM
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Great job ...... please post the rudder and bulb build as well man ......

I'm trying to follow every step



Quote:
Originally Posted by gordo62
Well I've started to build the fin. I used the foil spread sheet to give me the dimensions of the layers. I used 1/8th ply for the middle and 1/32 ply for the layers. The fin is 7 mm at the top and 4 mm at the bottom with a taper in the cord from 90 mm at the top to 70 mm at the bottom. This gives me about a 7.5% foil at the top and 5 % at the bottom. I'm waiting for the carbon fiber to arrive and then I will put 2 layers of carbon and one of glass that will hopefully give me about a 8.5% cord thickness at the top and 6% at the bottom. I happy with the shape after sanding and should be able to fair it out nicely with the epoxy and glass.

I know the production built fins are thinner but I don't plan on entering the world's so it should be ok.
Sep 02, 2008, 12:30 AM
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i'm about to do planking but sadly LHS here only have 1m balsa, should i join those strips with CA? Any comments?
Sep 02, 2008, 10:21 AM
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Balsa


Quote:
Originally Posted by lamafever
i'm about to do planking but sadly LHS here only have 1m balsa, should i join those strips with CA? Any comments?
Hi Iamafever:

You can either join them or you can order 48" balsa from the internet or talk to your local hobby store and see if they will order it in for you.

gordon
Sep 04, 2008, 10:05 PM
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Cebola's Avatar
Hello, I am from Brazil

I start my Vanquish hull on last Saturday, after cut all formers using laser cut, I recover the hull using balsa 1/8X1/4 from Midwest.
After sanding using#120, 180 and 240 the hull looks perfect and the work at this moment is made the deck.

This boat is joy to build, whit perfect lines, and very nice to see.

Mu boat is in pure balsa, sanded and maybe tomorrow I will apply PPG Putty VBA color beige, and after some 3/4oz glass coat.

Maybe tomorrow I post some photos of mine Vanquish, here.

Regards

Cebola
Brazil
Sep 05, 2008, 08:01 PM
Registered User

would like to see your photos


Hi Cebola:

Welcome I would like to see your photos. I agree with you it is a very nice hull to build, with very nice lines. You might want to use a bit heavier cloth than 3/4 oz on the outside. I used 1 3/4 oz on the out side and inside and still only weighted 380 grams. If you go that light you might end up putting all the weight back in with bracing on the inside to strenghten the hull.

I just got my shipment of carbon fibre today so will try and expoxy my fin this week end and then make the fin box and mount the fin.

Gordo
Sep 06, 2008, 12:56 AM
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Hi Gordo

Can't wait to see your build on the fin man ...... i'm a little bit slow on my planking. I'm doing it slowly cos this is my first build and testing my patience as well
Sep 06, 2008, 02:59 PM
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Cebola's Avatar
Quote:
Originally Posted by gordo62
Hi Cebola:

Welcome I would like to see your photos. I agree with you it is a very nice hull to build, with very nice lines. You might want to use a bit heavier cloth than 3/4 oz on the outside. I used 1 3/4 oz on the out side and inside and still only weighted 380 grams. If you go that light you might end up putting all the weight back in with bracing on the inside to strenghten the hull.

I just got my shipment of carbon fibre today so will try and expoxy my fin this week end and then make the fin box and mount the fin.

Gordo

Hello Gordo

My boat's hull, is whit one coat of 3/4oz glass coat.
I think you are right, and after sanding I will apply another coat of the same glass coat.
I intend to make my Vanquish in lack finish, very bright whit the balsa strips appearing.
Inside I am going to apply a 4oz fiberglass, using epoxy resin.

This boat is a joy to assemble, but I made some mistakes, like use light 1/8 balsa.
This makes the boat whit a overall weight of 180grams (until this photo).
Let`s see, whit the hull completed the final weight.

Some photos of the hull.
Hope you like it

Cebola
Brazil
Last edited by Cebola; Sep 06, 2008 at 03:19 PM.
Sep 06, 2008, 07:16 PM
Registered User

Wow!


Very nice hull Cebola! It looks great. I've put a coat of carbon fibre on my fin this morning. I don't have a vacum bag setup up so I used a couple of pieces of wood and clamped the carbon fibre inbetween them then suspended it so the weight of the fin is keeping the carbon fibre tight to the fin. I'll post a pic in a bit.
Sep 06, 2008, 07:29 PM
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here is the fin


I've put the first layer of carbon fibre on. I'll see how stiff it is once it has dried and decide if I'll put a layer of carbon at a 45 degree angle or just glass it.
Sep 06, 2008, 07:31 PM
Registered User

Glass weight


Quote:
Originally Posted by Cebola
Hello Gordo

My boat's hull, is whit one coat of 3/4oz glass coat.
I think you are right, and after sanding I will apply another coat of the same glass coat.
I intend to make my Vanquish in lack finish, very bright whit the balsa strips appearing.
Inside I am going to apply a 4oz fiberglass, using epoxy resin.

This boat is a joy to assemble, but I made some mistakes, like use light 1/8 balsa.
This makes the boat whit a overall weight of 180grams (until this photo).
Let`s see, whit the hull completed the final weight.

Some photos of the hull.
Hope you like it

Cebola
Brazil
I would go with one more layer of 3/4 on the outside and one layer of 3/4 on the inside. It will be plenty strong then and lighter than using the 4 oz.

Gordon
Sep 06, 2008, 08:03 PM
Registered User
Cebola's Avatar
Hi Gordo

Can you inform me, about the fin, measures and tick?
Is spruce strong enough to make the fin and rudder, or some hard 3/16 plywood is good enough?

About the hull, I think you are right, ĺ inside seems to be good and easy.

Sorry for ask too much, but this is my first boat, I became from aircraft models, gliders.

Regards


Cebola
Brazil
Sep 06, 2008, 08:45 PM
Registered User

fin


hi Cebola:

Its my first build too. I've done a lot of research on fins and it seems to be the most closely held information as its the only thing that is unrestricted in the iom class. The latest trend is a very thin tapered shape using a naca profile. I went with a 7% naca profile with a 92 mm chord at the top and a 6 % naca profile with a 70 mm cord at the bottom. I made it by using layers of 0.8 mm aircraft grade plywood and sanding it to shape. Its probably no where near the quality of the ones made by the commercial suppliers but it looks good It will probably weigh twice as much as the one made from a mold. I've never made anything from a mold and if this one doesn't turn out as good as I hope I might have to try and make a mold. I'll keep you posted. I found a program on the net in excel that gives you the dimensions for the layers based on a naca profile but it won't let me upload it.

Gordon
Sep 06, 2008, 08:48 PM
Registered User

link for excel program


http://www.duckworksmagazine.com/07/...trip/index.htm
here is the link for the fin I've made. It has a good explinaiton and the excel file to calculate the layers.

Gordon
Sep 07, 2008, 11:25 AM
Registered User
Cebola's Avatar
Hi Gordo

Airfoils I got some know how because of gliders, I suggest NA64009 that you can found on www.profili2.com .
I was thinking on a spar 1/8sq spruce inside the fin, and two layers of plywood 1/32 tick, and carbon fiber cloth around.
Another option is two layers of 1/8 Midwest plywood, and fiberglass cloth, but I sincerely donít believe that is strong enough.

A friend told me about a fiberglass piece 3/16 tick, used on integrated electronic circuits, hard but heavy for the fin and rudder blade.

I may confess I have a big doubt.

Cebola
Brazil


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