Seeking Stability, Maneuverability and Speed Feedback on Design

Tom; In your post number 20 you say that pod drag is miniscule. I vigorously contest that statement. The pod, of necessity, has a fin of some sort from which the pod is suspended. Do some arithmetic and calculate the frontal area of both the fin and the pod. Even if the fin and pod have a low drag coefficient the total drag is signifigant because the frontal area of the immersed parts is so high. Do the math and you will see.

As Par has suggested; appendages are to be avoided where at all possible. Low hanging appendages, among other disadvantages, contribute greatly to pitching momement. Accordingly that induces more drag because the pod will have alternately positive and negative incidence angles with respect to lines of forward progress. Not good!

 

Interesting observation, but if shaped properly would there not be a fair range of incidence angles within which drag was not much different ?

 

With some work, pods fairly close up to the hull bottom could be made to have relatively low drag numbers, but a long narrow hull with widely separated pods will likely experience a considerably trim moment, in all but slight incidence angles. The drive pod will be in the wake of the forward pod as well, further decreasing it's drag values. As shown, the pods have a spherical nose, which will be quite "draggy", though forgiving in incidence angles, but even elliptical or "piercing" shapes will have difficultly with the amount of area they bring to the equation.

 

What I had in mind was to marry this concept with a surface hull.

www.ise.bc.ca/dorado.html

No need to beat me over the head with how it wont work but if anyone would care to comment on ways it might, feel free.

I'm also working on a SWASH (not a typo, single hull) conceptual approach but with such a high displacement, it may end up as a tail dragger, prop in surface hull. I've driven a small, Russian passenger boat like this before.

-Tom

Edit: Oops, web-site above completed now, sorry.

 

This may work too but I don't know that I'll have enough thrust to get enough lift.

The prop would likely have a nozzle and the wing would not be as thick as shown.

Very likely far too much wetted area.

-Tom

 

I can't see it.

 

I had some trouble with it too.

Try entering it by hand.

-Tom

 

That web-site is pooched. Strange, they are a well established, local company. Oh well, never mind.

I've done the calculations and I think this design will "fly".

Drawings to follow...

 

Auto leveling via mechanical "spatula" actuators controlling both elevators and ailerons through the struts.

-Tom

 

THIS is the concept I've been envisioning...

http://www.youtube.com/watch?v=kRuUtOmMGR0&feature=youtube_gdata_player

Does anybody know where I can find more data on the power boat tests?

-Tom