[PSUBS-MAILIST] Vertical thrusters

[Alan via Personal_Submersibles]

David,
I would put it down lower so you have more propeller in the collar area
to get a bit of the kort nozzle effect & for visual streamlined look as it will
protrude more with a proppeller guard on it.
You will get some power loss with the wash hitting the sides of the horizontal
Tunnel, but maybe you could make the uncut hole much larger to eliminate
a bit of that effect.
Alan

> On 5/07/2020, at 7:55 AM, David Colombo via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Hi Alec, the 12" hole will be in the bottom as well. I just hadn't cut it out yet.  I'm thinking that that the prop will sit just below the grill which will be flush with the surface. Even with that placement the nose of the thruster may just peek out the bottom just a bit, so entanglement issues.
> David
> 
>> On Sat, Jul 4, 2020, 12:00 PM Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> Hi Dave,
>> 
>> Looking good! Surely there is a 11" diameter hole coming in the bottom of that tunnel? You wouldn't want to draw water in horizontally and expel it vertically - you'd want it to come in directly from the bottom and go out the top. And once you had that hole, the thruster maybe could also go a little lower, so that the prop was just below grade on the top skin. But the latter suggestion seems to me much less important than the first.
>> 
>> Best,
>> Alec
>> 
>>> On Sat, Jul 4, 2020 at 1:47 PM David Colombo via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>> Ok guys, looking for comments on potential issues with vertical thrusters. This morning I laid in the first vert thruster in the wing to mock up the attaching bracket to the hull. The twelve inch hole will go thru the wing. The questions are:
>>> 1) hold the prop flush with top surface or raised  slightly. I will be fabbing a grill cover.
>>> 2) as the prop can draw water from the bottom as well as thru the thruster tube, any concerns with prop wash being pushed out more laterally vs vertically. Wondering if i need to have a collar at least as deep as the prop?
>>>  You might be also wondering why I have 101 lb vertical thrusters. Never know when you might need to do a barrel roll maneuver.
>>> I appreciate the feedback
>>> David
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