RE: [PSUBS-MAILIST] Stopping Flaps

Brent,

High speed submarines have a defined speed/depth operating envelope that they operate within. Outside leads to a rapid depth excursion and potentially exceeding test depth and/or crush depth. All subs fear jammed dive planes especially during high speed maneuvers which would force the sub outside of the safe envelope. In the case of the Albacore, the drogue deployed from the edge of the fairwater (pulling from the aft upper end of the sail) caused a torque to be exerted on the hull, pulling it up out of a dive. The flaps just killed forward speed and thus assisting in keeping the sub operating within the safe speed/depth envelope. Many things were tried on the Albacore as this was all new operating ground since no other submarine had been able to operate at these speeds before. Most of the concepts tested on the Albacore never made it out into the fleet as they were not practical or were found not to be needed.

Fleet subs purposely operate a good distant off of the bottom to avoid unintentional collisions and unfortunately those few times that they have met with an uncharted sea mount or guyot have been tragic for the crew and resulted and damage that cannot be economically repaired…the sub usually has to be decommissioned.

In the case of typical PSUB-sized submersibles, high speed (greater than 3 knots) will have difficulty stopping or rising sharply in time to avoid obstacles in semi-murky water (visibility ~20 ft.). This is evident from experience gained working with human-powered submersible races. While these subs do not weigh all that much, they entrain a weight of water that is less than or comparable to that found in a PSUB. They go faster now, but my experience trying to stop and/or divert our record breaking sub doing 3.94 kts. at the end of the lengthy tank run was very difficult. This was with the crew stopping the prop and putting the fore & aft planes in a “hard rise” position. When a submersible did get away from the “catchers”, they were often damaged by the wall or the tank end. The “catchers” were lucky that no broken bones occurred as getting hit by a sub was very painful and left you black and blue for days.

R/Jay

Respectfully,

Jay K. Jeffries

Andros Is., Bahamas

Talk sense to a fool and he calls you foolish.

- Euripides (484 BC - 406 BC)

From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Brent Hartwig
Sent: Monday, August 25, 2008 8:41 PM
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] Stopping Flaps

Dean,

I found a couple more items. I'm having trouble finding a picture of the flaps open. I had one a while back.

http://imageevent.com/albacore/albacorehistoricphotos;jsessionid=r9qabaad11.tiger_s?n=25&z=2&w=0&x=0&c=4&m=24&p=24

"The parachutes were attached to the after end of Albacore's fairwater

and successfully streamed while the ship was cruising submerged. The resulting

deceleration curves indicated that such a system effectively aided in 

emergency recovery." 

Project "Bailout" might not have been the most successful of Albacore's

tests but it certainly showed some creativity was at work."



http://www.hazegray.org/navhist/albacore.htm

Regards,
Brent Hartwig

From: brenthartwig@hotmail.com
To: personal_submersibles@psubs.org
Subject: [PSUBS-MAILIST] Stopping Flaps
Date: Mon, 25 Aug 2008 17:03:24 -0700

Dean,

You could install some sort of stopping flaps (speed brakes) on both sides of your sub that are curved to fit the shape of your hull. Much like a US Navy test sub USS Albacore. Then operate them with hydraulics or adapted electric actuators starting with a unit like the Lenco Trim Tab actuators.

I've been planning on having this type or braking system on my winged underwater gliding subs. With two stopping flaps on the training edge of the wings. One opening up, and one down at the same time.

"Built as a test bed for the U.S. Navy, the Albacore featured a 

tear-drop shaped hull, new diving controls, a dorsal rudder and a new 

high-yield steel for her pressure hull. In addition, the Navy, at one time 

or another, experimented with speed brakes, contra-rotating screws, a 

drag chute, camouflage paint and three different arrangements of stern 

control surfaces.

The NSF report ignited debate within Navy circles over a variety of 

issues such as the merits of twin propellers vs. singles, and the sacrifice 

of surface stability for undersea speed. The result of the recommendations 

and ensuing debate was the U.S.S. Albacore.



The Dorsal rudder was reinstalled and enlarged and the boat 

was outfitted with speed brakes. These brakes - another concept borrowed 

from aviation - technology, consisted of 10 hinged panels ringing the 

after part of the ship. When needed, they were hydraulically opened into 

the waterflow, bringing the boat to a rapid stop."



http://www.hazegray.org/navhist/albacore.htm



http://en.wikipedia.org/wiki/USS_Albacore_(AGSS-569)

Regards,
Brent Hartwig

From: Recon1st@aol.com
Date: Mon, 25 Aug 2008 18:55:44 -0400
Subject: Re: [PSUBS-MAILIST] Air Tanks
To: personal_submersibles@psubs.org

Frank I am using 12hp for my main propulsion. I gave up trying to calculate speed but I should have

plenty. The reason for so much maneuverability is the bottom of Lake Superior many granite boulders

etc. I will need to travel pretty fast to cover any amount of the Lake. I am thinking of a 20 to 30' above the

bottom but at 6 knots or so when one of those big beast jumps up in front of me, I am going to need

options. A transfer pump or sliding weight for sure would not fit my needs. I may even have an

emergency sea anchor deployment for quick stops. Reverting back to my drag racing days.

I loved the dry dive video. I learned much watching it maneuver I have greater confidence that my

efforts should yield the kind of performance I am looking for. Not to mention it oughta be a real

hoot to drive hehehhe

Dean

In a message dated 8/24/2008 8:15:39 P.M. Central Daylight Time, ShellyDalg@aol.com writes:

Hi Dean. I think you're chasing the right idea with front and back dive planes. I had considered that but let it go because of the extra work. It just seems to me that back dive planes would be a real plus if you have enough power to make them work. Did you see the "dry dive" videos? With the center mounted dive planes the sub stays level when ascending/diving but it would be nice to be able to angle the sub just with the dive planes. Like you say, much like flying. I don't know how much speed you'd have to get to make the dive planes overcome the front/back balance, but if it's close enough to neutral, it may not take that much power.

Twin trim tanks front and back with a transfer pump would help if the pump was able to shift weight fast enough. Maybe a sliding drop weight would be less trouble to make. I will be able to shift the seat forward and backward a little and I'm hoping that will give me a little angle change. Damn, I wanna get this thing wet soon! Frank D.

It's only a deal if it's where you want to go. Find your travel deal here.

It's only a deal if it's where you want to go. Find your travel deal here.