Dan G
May 23rd 07, 06:51 PM
On May 23, 6:04 pm, Bob Kuykendall > wrote:
> Earlier, "Brian Glick" > wrote:>
>
> > The foam gets water logged...
>
> Quite, quite unlikely.
>
> The foam used in sandwich core composite construction is closed-cell
> foam that does not admit water beyond the first layer of cells. And
> even that layer is sealed by the sandwich skin so that very little if
> any core foam is exposed.
>
> History suggests that the majority of such water landings in composite
> ships resulted in floating gliders.
GRP sinks like a stone if the airspaces flood. I'm not sure how much
of a wing is actually filled with foam, but certainly fuselages are
just big empty tubes. If water starts coming in through control rod
openings, any gaps around the undercarriage etc. you're going down.
Fast. I think it depends on the glider how long they float - K21s sink
very quickly, flooding through the main wheel well. On the other hand
I've heard that in Finland lake landings aren't uncommon, as in large
areas lakes are the only places without trees for miles around!
The truth is out there....
Dan
> Earlier, "Brian Glick" > wrote:>
>
> > The foam gets water logged...
>
> Quite, quite unlikely.
>
> The foam used in sandwich core composite construction is closed-cell
> foam that does not admit water beyond the first layer of cells. And
> even that layer is sealed by the sandwich skin so that very little if
> any core foam is exposed.
>
> History suggests that the majority of such water landings in composite
> ships resulted in floating gliders.
GRP sinks like a stone if the airspaces flood. I'm not sure how much
of a wing is actually filled with foam, but certainly fuselages are
just big empty tubes. If water starts coming in through control rod
openings, any gaps around the undercarriage etc. you're going down.
Fast. I think it depends on the glider how long they float - K21s sink
very quickly, flooding through the main wheel well. On the other hand
I've heard that in Finland lake landings aren't uncommon, as in large
areas lakes are the only places without trees for miles around!
The truth is out there....
Dan