*


All times are UTC + 1 hour



Post new topic Reply to topic
 [ 24 posts ]  Go to page 1, 2, 3  Next
Author Message
 Post subject: More questions (hopefully not stupid ones)
PostPosted: Wed Dec 10, 2014 1:29 am 
Offline
Frequent Poster

Joined: Wed Jan 01, 2014 9:15 pm
Posts: 277
I've decided it's time. I'm going to try and mimic Denisesewa (viewtopic.php?f=196&t=2386805) to some extent (which is based on the seabreeze plans by Phezulu1). I found a local source of okoume (3 or 4mm, not sure which yet) that I'll be using for the core.

I've made dxf drawings to represent the dimensions Phezulu1 used:
http://www.thingiverse.com/thing:584300
Image

I've done some reading, looked at some dimensions, and read a lot of stuff that doesn't really make a whole lot of sense to me....I just want to build something to learn on honestly....

So now I've got some questions:
1. I see that a lot of things work, maybe some better than others, but that 'machine tolerances' aren't really a requirement. That said, some people seem to use flat wings, and some positive lift in the front and negative lift in the rear...why and what?

2. When someone says, "I have a 960mm mast", are they measuring from the top of the fuselage or is it the whole assembly?

3. There will be more I'm sure....


{ SHARE_ON_FACEBOOK } { SHARE_ON_TWITTER } { SHARE_ON_ORKUT } { SHARE_ON_DIGG } { SHARE_ON_MYSPACE } { SHARE_ON_DELICIOUS }
Top
Profile
 Post subject: Re: More questions (hopefully not stupid ones)
PostPosted: Wed Dec 10, 2014 2:56 am 
Offline
Very Frequent Poster
User avatar

Joined: Wed Aug 24, 2011 11:39 am
Posts: 1201
don't worry about the angles yet, concentrate on making it rigid and strong at the joints.


Top
Profile
 Post subject: Re: More questions (hopefully not stupid ones)
PostPosted: Wed Dec 10, 2014 3:11 am 
Offline
Frequent Poster

Joined: Wed Jan 01, 2014 9:15 pm
Posts: 277
Hawaiis wrote:
don't worry about the angles yet, concentrate on making it rigid and strong at the joints.


Thanks...some of that was directly aimed at you. ...I'm going to make the fuselage perpendicular to the board so I can tweak the lift surfaces later if need be. If I were to use one type of carbon cloth (not caring about presentation) what should I purchase? I'm not super concerned about cost....


Top
Profile
 Post subject: Re: More questions (hopefully not stupid ones)
PostPosted: Wed Dec 10, 2014 7:47 am 
Offline
Very Frequent Poster
User avatar

Joined: Wed Aug 24, 2011 11:39 am
Posts: 1201
I am not very good at Carbon Fiber, Any Expert want to chime in?


Top
Profile
 Post subject: Re: More questions (hopefully not stupid ones)
PostPosted: Wed Dec 10, 2014 10:39 am 
Offline
Medium Poster

Joined: Sun Jul 15, 2012 9:32 am
Posts: 108
Location: Tauranga, New Zealand
I'm sure the pretty weave cloth is only used on the outside for looks. Mine was mostly Unidirectional with +-45 Deg layers near the outside where they are more effective.


Top
Profile
 Post subject: Re: More questions (hopefully not stupid ones)
PostPosted: Wed Dec 10, 2014 3:25 pm 
Offline
Frequent Poster

Joined: Wed Jan 01, 2014 9:15 pm
Posts: 277
What do you mean by "near the outside where they are more effective"?

I was thinking of just using biaxial weave. What weight are you using? I suppose this line of questioning might be more geared toward the board maker forum.

edit: and I plan on gusseting or adding a flair type boss on the mast->mount point as Rev suggested elsewhere. I think I have a decent plan in place from all the great guidance I've read through here, and a few people have posted exactly how, what weights, types, of carbon/glass they've used, but I was hoping to just make a single order if possible, and I don't mind paying for it all. Also, I have a bit of West Marine epoxy laying around, and was planning on going with this....let me know if I should use something else.


Top
Profile
 Post subject: Re: More questions (hopefully not stupid ones)
PostPosted: Wed Dec 10, 2014 11:53 pm 
Offline
Frequent Poster

Joined: Wed Jan 01, 2014 9:15 pm
Posts: 277
A different possible direction:

I found a place locally that can make complex EPS foam shapes. Instead of using okume wood, I could have this place (assuming cost isn't too steep) cut out all the foil bits for me and I just wrap it in carbon (I know I'd need a lot of carbon but that's ok). Is this a good idea?


Top
Profile
 Post subject: Re: More questions (hopefully not stupid ones)
PostPosted: Thu Dec 11, 2014 12:27 am 
Offline
Very Frequent Poster
User avatar

Joined: Wed Aug 24, 2011 11:39 am
Posts: 1201
From my limited experience with carbon. The best way is to make a mold, which I have not done. Another is to make a carbon skin over wood, which I have done. Works well. There are people that can make them much better with vaccum bagging etc.


Top
Profile
 Post subject: Re: More questions (hopefully not stupid ones)
PostPosted: Thu Dec 11, 2014 1:26 am 
Offline
Very Frequent Poster

Joined: Sun Feb 12, 2006 8:16 pm
Posts: 574
Location: Kettle Point Ontario Canada
you don't want eps inside of your foil it will off gas and may bubbles... Hawaiis knows about off gassing in foils from one he had and bubble in the plate mount. if you want to use foam you need closed cell ( corecell or dinvy) which will not off gas when they get home on the beach in the sun.

either way you need the right about and type of carbon to make it strong enough and little flex in it.

Molds are not fun to make. a lot of time and work to make them by hand. Sanding and polishing but you can do it if you take your time and have some skills. I just say watch a lot of youtube on mold making.
I just say a lot of release agent is your best friend or all your work and the plug is trash

terrie
www.jellyfishboards.com

t3rse wrote:
A different possible direction:

I found a place locally that can make complex EPS foam shapes. Instead of using okume wood, I could have this place (assuming cost isn't too steep) cut out all the foil bits for me and I just wrap it in carbon (I know I'd need a lot of carbon but that's ok). Is this a good idea?


Top
Profile
 Post subject: Re: More questions (hopefully not stupid ones)
PostPosted: Thu Dec 11, 2014 1:56 am 
Offline
Frequent Poster

Joined: Wed Jan 01, 2014 9:15 pm
Posts: 277
Sounds like I need to use wood...

I could always melt out the foam but I guess in the end I'd still have to have a vent.

If i get something that works I'll consider making a mold. Sometimes I have that kind of patience and sometimes I don't...

I'm thinking of running a bit of uni up and down the mast and the on the fuselage and then using biax or weave on top. I'll sandwich the wood with glass. I guess I could get away with just uni if I run it right; I was worried about higher modulus uni and bash resistance but with a wood core it would always be repairable.

Thanks for the info.


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic
 [ 24 posts ]  Go to page 1, 2, 3  Next

All times are UTC + 1 hour


Who is online

Users browsing this forum: S4mb0 and 11 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group