[PSUBS-MAILIST] Vertical thrusters

[David Colombo via Personal_Submersibles]

Hi guys, i completed the placement on my vertical thruster. Tomorrow I will
need sending to the cnc to cut the support arm for each of the 4 horizontal
thrusters. Turns out the thruster just peaks out the bottom. My temporary
grill is a bbq grate. If it was only stainless steel.
David.



On Sat, Jul 4, 2020, 11:56 PM David Colombo <seaquestor at gmail.com> wrote:

> Hi Alan, Im thinking the same thing. The collar should be 2-3 long below
> the flush grill with the top of the wing. Aesthetically I think the flush
> grill will look better.
> David
>
> On Sat, Jul 4, 2020, 1:33 PM Alan via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
>> 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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>>>>
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>
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