DeBoers Concept II pump jet

[Tom Martin]

Hope Bob Martin won't mind me posting a bit about this build. He has taken on a DeBoers Concept II with pump jet propulsion (for me).
This will be my first R/C and a pump-jet first for Bob.
He custom built the manifold and has the system totally functional. Ballast is the final hurdle as it is very tight in this narrow hull….

Tommie

[RCSubGuy]

Don't mind at all! Saves me the hassle of posting myself!

As of this morning I have the upper and lower hulls primed and I'm fitting custom foam for flotation. I'm worried about the weight in the rear. We'll see how she floats this weekend!

[He Who Shall Not Be Named]

This is what I came up with:

https://www.youtube.com/watch?v=YQhwInH3zEY

M

[Tom Martin]

Bob Martin completed my Seaview and posted a YouTube clip:

https://www.youtube.com/watch?v=MZCXZ6sV1yU&feature=youtu.be

I think she's fantastic!

Here's a few pix.

[He Who Shall Not Be Named]

Well done, sir!

M

[greenman407]

Really cool! Are there any plans to make it submerge or is this a dynamic diver? Makes me want to order one.

[RCSubGuy]

This guy is a surface runner. The twin pumps take up too much real estate to convert to static, but I suppose a dynamic diver would be possible with a new watertight cylinder that included a servo for pitch control...

[He Who Shall Not Be Named]

Really cool! Are there any plans to make it submerge or is this a dynamic diver? Makes me want to order one.

You would go this route:

https://www.youtube.com/watch?v=YQhwInH3zEY

https://www.youtube.com/watch?v=T5rVYcF6Yew

M

[Von Hilde]

Great concept with the Gimbled Kurtz. I see in the video, the initial manuvering performance was a tad short of optimal. Thats what shakedowns are for. I think if you vectored the water after the turbine, instead of having the kurtz itself do all the work. There is some restrictions with the peripheral angles due to the universal in the drive shaft. If the turbine is stationary in a venturi, the water can be diflected after the unit with just a gimbled thruster. Picture a hot tub jet, ball socket type of thruster. The sub design itself is possibly a hinderance in performance with the fantisy hydro effects spoiler bow. 1960s futuristic isnt really practicle. However if you "flew" the craft underwater with roll/pitch/yaw using the bow design like a canard. With the vectored thruster aft that had a 180 or a little less degree radius It could turn in its own liength, like a jet ski or a PCF swift. Another option would be like a Higgins tunnel hull, and the clamshell rudder, with a fancy multiblade cleaver prop.

[He Who Shall Not Be Named]

Great concept with the Gimbled Kurtz. I see in the video, the initial manuvering performance was a tad short of optimal. Thats what shakedowns are for. I think if you vectored the water after the turbine, instead of having the kurtz itself do all the work. There is some restrictions with the peripheral angles due to the universal in the drive shaft. If the turbine is stationary in a venturi, the water can be diflected after the unit with just a gimbled thruster. Picture a hot tub jet, ball socket type of thruster. The sub design itself is possibly a hinderance in performance with the fantisy hydro effects spoiler bow. 1960s futuristic isnt really practicle. However if you "flew" the craft underwater with roll/pitch/yaw using the bow design like a canard. With the vectored thruster aft that had a 180 or a little less degree radius It could turn in its own liength, like a jet ski or a PCF swift. Another option would be like a Higgins tunnel hull, and the clamshell rudder, with a fancy multiblade cleaver prop.

It's a pump-jet, not a Kort nozzle. The two are often confused. Also, a turbine extracts energy from the axial motion of a fluid and converts it to a torsional force to a shaft. A rotor, or 'propeller' imparts an axial force to a fluid through radial motion.

Yeah, I tried both a gimbaled 'jet-vater' type thrust vectoring device aft of a fixed propulsor -- this was the origional DeBoer arrangement. I found the efficiency of the thing to be poor; it just did not produce the yaw and pitch forces required to push this piglet around properly. And the thrust lost to jet-vater drag was horrendous! Those observations led me to the current arrangement, though not able to push the ass-end around as I would want, is just good enough to make the Concept-2 SEAVIEW navigable underwater.

I limited shaft drag by a telescoping arrangement: As the pump-jet gimbaled the shaft would contract/extend the required amount to make up the longitudinal displacement of the rotor shaft. By making the intermediate drive shaft from squar tubing the unit would translate axially, but would not slip radially.

By 'flying' underwater I assume you mean banking into the turns. Does not work with lighter-than-air vehicles or submarines -- for the same reason.

An airplane, a heavier-than-fluid vehicle, is always generating lift to fight the ever present force of gravity, it can alter the lift vector by banking (rolling). But, if altitude is to be maintained, more power has to be applied to generate the lift lost by moving the lift vector off vertical -- that off-vertical lift becomes a yawing force, i.e. banking-into-the-turn.

The submarine negates the force of gravity by producing an equal opposing force: buoyancy. For the submarine to achieve a turn without introducing a pitching moment, it would have to roll a perfect 90-degrees. Possible, but not suggested. I found this out the hard way, trying to 'fly' my big FS-1 into turns.

[Von Hilde]

Wow, thats awsome. Looks like a long hard learning process, by the picture, unless thats your grandson holding the USO. {Just kiddin} I use to think a real flying sub was quite feasable for an SDV situation and had some ideas, after taking a look at some contemporary VTOL experimentals, that come in and out of our operating area. Not hard to visualise a "Transformer" zoom into global position and drop in and get wet with the flip of a switch and bubble in to the beach to drop off the 6 man liberty party some evening.

[He Who Shall Not Be Named]

I've always been a fan of the Convair FS concept. Got as far as wind tunnel and water trough studies.

It's on my bucket-list

M

[Von Hilde]

I've always been a fan of the Convair FS concept. Got as far as wind tunnel and water trough studies.

It's on my bucket-list

M

The Convair still had the old Flash Gordon concept like the russians flying sub and flying tank ideas. Kind of Jules Verne enginearing. Now days we can make a brick fly aerobatics with the computerised stabilisation, like in the Harriers and F35. The operators reaction time could never keep up with the speed of the course of events, back in the day. The DARPA 6 man is getting closer to what I was thinking about. Still has the ugly wing and the engine necals protruding. The folding flip out props are kind of neet, like on the mini UAV hand launched recon birds. The prop domes on a full size would be a nightmare to deal with. I think jet, with several vectoring nozles, no lifting wings or appendages. Closer to the Voyage to the bottom of the sea FS design flying saucer or disc with prone positioning of the PAX and possiblly gimbled compartment, like a ball in the center, almost like a flying Saturn. A giant Gyroscope type of affair. The ball structure is the optimal shape for pressuriseation to begin with. A handy escape pod as well. If I could round up an old WWII surplus "Die Glocke" to power the thing, I would apply for a grant and get Jessy James out of the Monster Garage to whip one up for me to sell the Gov-mint. I tried to post a picture of the DARPA but I got some flack from the Men in Black

[Tom Martin]

Made final changes and paint detailing.
I think Bob M's concept of removing the bow windows makes the boat look menacing. The GORT of submaries!
Trim test next...
Tommie