cyrus77

iTrader: (4)

Using finite element analysis FEA on a Formula 302

To get it stronger and lighter.

First I drew the hull. Close not exact.


Original bulkheads and stringers


New ideas
I am looking to use COOSA so I can hole saw 6" holes in all the stringers for weight. Only one stringer showing lightning. I still need to get a few dims closer. I hope to run FEA to see if I can improve upon the heavy original design.

Cheers,

cyrus77

iTrader: (4)

Also this boat is made in 3 pieces the rear, the area drawn, and the front box stringers.

scippy

iTrader: (3)

If I follow this, your starting wiith a bare and gutted formula 302 hull?..............wouldn't that be a heavy starting point regardless of the non wood reengineering?

Keith Atlanta

Cant do the holes. As strong as you think Coosa is, you would probably be better off with foam and a better composite.

FWIW - I use to sell a fatigue and durability software. They used it to put a JSF 35 into a 12G turn in a giant fixture with 100's of strain gauges at LMCO in Dallas. Talk about cool!
Right now you are just ballparking... Averages of averages of a hull that is kinda the same is a REALLY dangerous proposition. While it can be done, its just lipstick on a pig.

phragle

iTrader: (3)

I would thing that by the time you add all the glass and resin on the inside of the swiss cheese you would negate the weight saving of swiss cheesing it. Its not billet metal where you just make a hole and your done...

cyrus77

iTrader: (4)

Here are my thoughts (I am no means a boat expert or pretend to be)

The 302 Formula is a very light boat 6950 lbs Dry. Not bad for an old scow.

As far as the holes.
I am just thinking about it. I called coosa they said you can bore holes as long as it is structurally sound (meaning the coosa "bluewater 26" and plywood are equivalents, So if it strong enough in plywood it should be in Coosa.) And Coosa is 30% lighter to begin with.

As far as the design:
1. If I put new stringers in it, it is ahead of all of the rotten ones that are still being used.
2. It is pretty simple to see what the designers were accomplishing with there design, seem pretty straight forward to improve upon this as I am only doing a variation.
3. I have more FEA tools then Formula had when they designed the system orignially.

Also I was not planning on glassing the holes in. I would leave them bare and glass only where it required. I agree glass them would negate any weight savings.

Cheers

cyrus77

iTrader: (4)

Please clarify.
Thx.

glassdave

iTrader: (1)

your will probably add more weight to the Coosa by hole sawing it and you will compromise its ability to carry a load, its not like metal, you will have to band the edge of the holes in a layer or two glass that will probably weigh about what you just cut out. Your best bet if you want to lighten this thing is going to be a simple well thought out (balanced) laminate schedule. using preforms is a good choice as well but you can also go with one of Coosas lighter panels and rely on your laminate for the load. You may want to also think about bagging everything.

I work with Coosa all the time and would not consider drilling those kind of holes. its a great product but as a stand alone panel with swiss cheezed holes your gonna be pushing it

glassdave

iTrader: (1)

I typed that as you replied that you would not be banding the holes. without any sort of roundover and a layer of glass stress will propagate very quickly. this is a very dynamic environment

cyrus77

iTrader: (4)

Glass Dave Thanks
Scratch the hole idea. What kind of preforms?