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Patrick Henry Turning Question - Too much space needed

R/C Submarine modelers

Postby witchblade » Tue Nov 04, 2003 12:22 pm

Hi guys,

I have a question for the experts. I have a Patrick Henry from Engel. Nice ship, currently upgrading wit a lot of extra's (still trying to make the tridenthatches to work).

Since I have to rebuild the complete inside of the ship I was wondering. Can anybody tell me how I can make the turning radius a lot smaller. It's about 10 to 11 metre (33feet?) now. Anyway, a lot.

thanks in advance,

Danny van Dijk
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Postby Silent Hunter » Tue Nov 04, 2003 11:55 pm

Well...... you could install a bowthruster. Might be cheating, but you'd get lotsa comments about how hi-tech your boat is I'll bet. You could also go way out and custom create a vectored rear prop. Anyway you look at it it's gonna be a bit of a challenge. These boats just don't turn on a dime as supplied. They do turn a whole heck of a lot better underwater though, than on the surface. Good luck. :D
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Postby Davy » Wed Nov 05, 2003 5:30 am

Any chance that you can add an extra section on the lower rudder?

It can be fold down. If you can - that will certainly aid the turning circle. It worked well on my R7 submarine. I realise that it is not true scale, however. Small scale rudders seem to be blanketed by the hull. You may also find that fore and aft trim has an effect - the rudder needs to be in clear water.

Something like the rudder on a model yacht is the thing to aim for.
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Postby USS Silversides » Wed Nov 05, 2003 9:01 pm

Even though I still haven't completed a sub, I have seen other peoples subs with a rudder extension made from Plexiglass or Lexan or something transparent. This might not work very well, but just another idea :D

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Postby Davy » Thu Nov 06, 2003 5:53 am

Yes, I forgot to mention this. One of our club members also uses a clip on Perspex (Plexiglass) lower rudder extension and this does the job without being too obvious.
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Postby Bigdave » Thu Nov 06, 2003 11:29 am

My best friend has been running his for for at least 8 years and has no problem turning in his pool. 18X33 FT. It does not have alot of room to spare but it does it. Make sure you are getting maximum rudder travel. You may want to try and make the rudders scale. On the real sub the rudders pivot in the center. Not on the leading edge as in the Engel kit. Good Luck, Dave.
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Postby Slats » Mon Nov 10, 2003 7:53 pm

I would definately NOT add a bow thruster. The conventional wisdom on this topic has been extensively discussed before. Any thruster that is added for a RC sub will have greatest effect if mounted in the stern.

Before going to the hassle of adding a thruster - consider weight. I am advised by Matt Thor et.al, that weight is crucially important related to turning as mass momentum is higher / harder to overcome with higher weight on board. If you are using a sealed lead acid battery - you may wish to consider lower weight metal hydrides or a lower capacity sealed lead acid battery. The location of battery weight in the bow can also make turning sluggish.

Weight is crucial I am re-engineering my 72 scale Alfa, not a large boat, but one with very small rudders. Reducing the battery weight but half has improved the turning radius by about 30%.

Hope this helps.
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Postby witchblade » Mon Nov 17, 2003 4:22 am

Thanks for all the advice. I went for a little rebuild. I added an extra opening at the back of the sub. Now I can reach the area behind the divetanks. I got rid of the old motor and planted a new one (Robbe Decaperm). Furthermore I added a bowthruster from Graupner. It's a very small but effective little device without a prop. I'm also going to rebuild my rudders and the linkage to them. They began to be sloppy. Turning circle without speed: about 0 metres. in motion less then 3 metres (9 feet?).

In the future I'm going to build one of those thruster in the bow too. Not very scale but it makes turning even easier and as a bonus I can, with the flip of a switch, move sideways. This is only usefull when our club has a demo somewhere and the modelharbour is a bit cramped with yachts and tugs. By the way. It's very funny to park a sub between AND under tugs with just the tower above the waterline. You should see the looks on the faces of people who don't expect this.

Thanks for the input guys,

Danny van Dijk
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