Glen,
I am with you concerning the need for diving planes while Vance has experience with commercial subs with planes. Someone this morning brought up the side subject of effective fin design (Frank?) and thus my sketches from class. There are a bunch of calculations that went with those but the list does not need to be bored. Fins to be effective have to be large in nature at PSUB speeds. A large rudder on a vessel is often a patch for bad weather helm. Good luck with your flights!
Resepectfully,
Jay K. Jeffries
Andros Is., Bahamas
Save the whales, collect the whole set.
R/Jay
From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of glen brown
Sent: Sunday, September 13, 2009 7:25 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Dive planes
If I look at at any rudder and I see that rudder to be out of proportion In other words to large it tells me only one thing that it is inefficient the very reason for it large surface area is to try and gain some sort of pressure difference which makes absolutely no sense whereas a thruster that rotates is efficient thus the harrier jet I also don't see any reason why one could not use wings or fins in an application where pos lift is needed to trim the sub
but lift for any other reason does not make sense to me I want to dive I have gravity if I want to surface I have buoyancy what a bargain this was not an invention just an observation imagine if the Wright brothers had it that easy we would have never heard of them just joking I need some sleep since I started building my sub I have become a weight lifter welder fitter and turner and despite all these new talents when people ask me what I am up to and I tell them 80% still react in a uncontrollable laugh
at the end of October I have to start flying again can you believe I am actually dreading it to all of you thinking about starting your own build its fun its also humbled me as my reject pile can attest to .
----- Original Message -----
Sent: Monday, September 14, 2009 1:11 AM
Subject: RE: [PSUBS-MAILIST] Dive planes
Glen,
While some aspects of aviation carry over to PSUBs, the much greater density of the fluid medium changes how fluid dynamics apply. A typical fin for a PSUB just because it doesn’t have laminar flow does not mean that it is stalled otherwise a rudder or a fin keel on a boat would not work. Yes at higher angles of attack, they will stall but noting we should see in a PSUB.. The greatest amount of hydrodynamic development work with the K-350 should be focused on changing the shape of the forward main ballast tank to improve towability and minimize the forces while towing that want to drive the bow down. If I remember correctly, at speeds less than 3 kts. (K-350 speeds) fairings do not do much for the reduction of drag. Maneuverability of a helo at slow speeds does not have correlations with maneuvering a K-350.
Reserve buoyancy of the K-350 is another issue that could be improved.
R/Jay
Resepectfully,
Jay K. Jeffries
Andros Is., Bahamas
Save the whales, collect the whole set.
From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of glen brown
Sent: Sunday, September 13, 2009 5:56 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Dive planes
Any kind of addition such as wings ect regardless of design create drag which equates to more energy spent slower speeds and less monouvability only addition that I can see helping at our speed is the addition of fairings to try and streamline our existing designs why would one want wings(fins) when one has no laminar flow over them that means they are permanently stalled in other words not functioning I remember when I used to fly a Cessna 210 I owned a couple of years ago on circuit one of the things one would do is deploy the landing gear it used to feel as if you put the brakes on I now fly only helicopters and at slow speeds rely on Thrust I know water is a different medium but I think the design of most psubs are not exactly designed to be speedsters after all you not exactly cruising hundreds of miles but the very fact that they can hover and are slow make them very appealing to me flying fast through the air is boring but capturing game or rescuing someone in the mountains is great besides most a/c are so designed that if you let go of the yoke it will fly its self how boring . at present airbus is training special dogs to fly in the cockpit with there pilots and they are trained to stop the pilots from touching the controls the pilots sole purpose in future on fixed wing will be to keep the pax happy joke .He;licopters are difficult to handle at low speeds which I am sure my K350 will also be especially in open seas but I think regardless of how unstable it may be with practice one should be able to master it where as a stable boat will be easier to control but harder to manouver.Without proper research any wing design could make the boat uncontrollable at slow speeds.This Is only my opinion I could be wrong.
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