Serious Project : Off with my Canopy !!!!!

[Sean H]

Is that what Jimmy Lee is calling it?

How did you arrive at your pressure figures? I calculate 140 mph water pressure to be 289.69 lbs per inch* are you merely multiplying this by the surface area?

Reference 200 mph water pressure is 591.21 lbs per inch*

100 mph water pressure is 147.80 lbs per inch*

Those numbers are impact loads off the cfd and fea programs. The big numbers were obviously when very small areas took the full impact of an 140-0 scenario.

 

[AIR TIME]

knot Right, Gerry just bought a windshield ,I think its 1'' thick in front has a curve on both ends and the sides are either 1/2'' or 3/4. its a 3 piece set. the co builds them 4 pieces mostly. and the cost was 4 to 5 grand and made out of the real f16 canopys which I think is the polycarbonate. I can tell him about this post and he can give you the companys phone#. they do them for race boats two. now he is looking at whats the best way to install it . this is a non lid skater46 6 seater. art

 

[Rik]

Wouldn't you have to calculate in the weight of the boat, plus the speed of the impact?

?? The water being struck would be the same as the water being pressured so a 90 degree hit would equal the water pressure then I would guess spread this over the area exposed and you come up with an effective area of pressure. The deflection angle less than 90 degrees would lessen this force and the shape itself has to play a role in it.

The weight of the boat (mass) * Pressure would be an even higher # assuming mass of 10K * pressure of 289 = 1,890,000. Would you or the boat survive this if that was accurate?????

So I was thinking back to the Area * Pressure. A toothpick is hard to break if short enough. A long board is easy to break as we enter into the realm of "Leverage" so a lot of things have to be taken into account.

Imagine a piece of plastic one square inch in size secured into the boat. How much force would it need to see in an impact to fail vs the same material with an area of 1300 in*???

Also, I've noticed our Southern Hemisphere and Middle Eastern racers use a flat panel in a semi V shape for a front shield and in the States we use a compound radius shape. Which is actually better for the occupants on board?

 

[Rik]

knot Right, Gerry just bought a windshield ,I think its 1'' thick in front has a curve on both ends and the sides are either 1/2'' or 3/4. its a 3 piece set. the co builds them 4 pieces mostly. and the cost was 4 to 5 grand and made out of the real f16 canopys which I think is the polycarbonate. I can tell him about this post and he can give you the companys phone#. they do them for race boats two. now he is looking at whats the best way to install it . this is a non lid skater46 6 seater. art

Gerry got a 3/4" piece of acrylic from Shields taken off the 55' MTI molds.

 

[Ratickle]

Here's the guide for forming Polycarbonate 's. Almost identical to Plexiglass, including temps.


http://www.theplasticshop.co.uk/pla...exan_polycarbonate_sheet_processing_guide.pdf

 

[Steve 1]

Here's the guide for forming Polycarbonate 's. Almost identical to Plexiglass, including temps.


http://www.theplasticshop.co.uk/pla...exan_polycarbonate_sheet_processing_guide.pdf

I used to use the big powder coating ovens at the plant, word of caution is needed so that a Fresnel effect is not had by the "creative bending"

 

[Ratickle]

Rick, how thick is your F16 canopy you currently have?

It looks as if a 4 x 8 sheet of 1/2" thick polycarbonate is less than $600 pretty much everywhere.

Is 1/2" thick enough for a 100mph boat if mounted correctly???? And I know there is no way to say for absolute positive in all instances? But, I believe that is thicker than the canopy windows on the Batboats.


http://www.usplastic.com/catalog/pr...tegory_name=68&product_id=10718&cookie_test=1

 

[Ratickle]

On these styles, blown up from Rick's pictures, they are using flat windows in a similar canopy to most designs. Any reason against it in these lighter, slower, smaller designs?

 

[Bilgerat]

That flat slight v is where i am going with my design, however much more support and i would assume thickness, than what i see here. these plastic pieces look to be secured only an couple inches all the way around and riddled with holes, I wouldn't suspect that will work.

 

[Steve 1]

Rick, how thick is your F16 canopy you currently have?

It looks as if a 4 x 8 sheet of 1/2" thick polycarbonate is less than $600 pretty much everywhere.

Is 1/2" thick enough for a 100mph boat if mounted correctly???? And I know there is no way to say for absolute positive in all instances? But, I believe that is thicker than the canopy windows on the Batboats.


http://www.usplastic.com/catalog/pr...tegory_name=68&product_id=10718&cookie_test=1

Actual load @150 PSI with NO safety factor easy one figure your open area and apply the loading with a factor of what your life is worth.

 

[Ratickle]

Actual load @150 PSI with NO safety factor easy one figure your open area and apply the loading with a factor of what your life is worth.

Well, today not as much as before this great recession.....:sifone:

 

[Steve 1]

Well, today not as much as before this great recession.....:sifone:

LOL same here!

 

[Ratickle]

Clear Polycarbonate

MECHANICAL PROPERTIES:
Specific gravity (ASTM D 792) : 1.20
Tensile strength, Ultimate (ASTM D 638) : 9,000 p.s.i.
Elongation at break (ASTM D 638) : 130%
Tensile modulus (ASTM D 638) : 3.1x10~5 p.s.i.
Rockwell hardness (ASTM D 785) : R118
Impact strength (73° F) (ASTM D 256) (notched) : 17.0 ft-lb/inch
Flexural strength (ASTM D 790) : 14,200 p.s.i.
Flexural modulus (ASTM D 790) : 3.4x 10~5 p.s.i.
Wear factor against steel 40 psi 50fpm : 2500x10~10
Coefficient of friction 40psi 50fpm : 0.38 Dynamic

 

[Steve 1]

Elongation is worth noting.

 

[Ratickle]

I keep finding it cheaper and cheaper.

1/2 X 48 X 96 Polycarbonate Sheet-MOTOR FREIGHT ONLY
$444.00 $365.20 Sale Price
PC504896

 

[Steve 1]

It has a strange history, I was talking to a chick a while back and she was Dr Foxes Lab Intern and the story was true ,it came about as a glitch in Polyester research at GE.

 

[Sean H]

only Dr Schnell and the germans at Bayer beat Dr Fox to it by a week or so...

 

[2TR]

Rick, how thick is your F16 canopy you currently have?

It looks as if a 4 x 8 sheet of 1/2" thick polycarbonate is less than $600 pretty much everywhere.

Is 1/2" thick enough for a 100mph boat if mounted correctly???? And I know there is no way to say for absolute positive in all instances? But, I believe that is thicker than the canopy windows on the Batboats.


http://www.usplastic.com/catalog/pr...tegory_name=68&product_id=10718&cookie_test=1

I'm about 1" think, maybe more in the curved part of the canopy.

 

[Ratickle]

I'm about 1" think, maybe more in the curved part of the canopy.

So far I have not found 1" available by the sheet. However, if the flat panel concept is used, two sheets of 1/2", in theory, should be stronger by a little. I'll keep hunting, and make some calls.

 

[Ratickle]

Dean, Dave - Do you recall what the thickness was on the poly when you stuffed the Batboat? And did you use the same thickness when you replaced it???