jordan gutteridge

hello there i am planning on building a twin electricmotor rc rescue boatto retrieve my gas boats when they are stranded.the main body isessentially a barge but it has two sponsons to raise it outoff the water. on the front of the boat will be a U shape frame of 32mm push fit pipework to form a forkand it will be connected to a servo so it can be tilted/raised out of the water to reduce drag when sailing out to the stranded boat and will be droped to grab the boat when it arrives. the craft will be powered by 2 brushed 7.2v 540 motors high torque (70 turn) and to steer the boat i will use tank steering method so just power one motor to turn it in the right direction so there will be no need for a rudder. the only problem/questioni do have is aboutthe prop setup, is it really essential tohave counter rotating props on a slowreving/moving boat like this its just i cant find many reverse props on the net andthe ones i do find are threaded and i much preferthe drive dog type because surely if it is threaded when i put the boat in reverse the prop will tend to unscrew of the shaft. the main body of the boat will be made of very good quality 3mm plywood and will be supported by a series of bulkheads.

p.s i must say that this is my first electric powered build so any advice will be appreciated

regards jordan

*delete M i k e u p delete*

Suggestion only; escs should have reverse, especially wheb encountering weed patches and really tight are.

jordan gutteridge

hello mike yess i have sorted out the speed controller i am getting2x 200 amp ones from r2 hobbies in hong kong 2 for £15 bargain and they do have reverse function so that will help turning i can put one in reverse and the other one in forward so it will turn on a sixpence thanks for your help.

mfr02

While twin props are generally best with counter rotation, it usually means on a single hull, preventing torque roll and enhancing the effect of the rudder.  In an application like this, wide and no rudder, it should make no difference at all.

jordan gutteridge

hello there thanks very much for your help that has answered my question i will just get two props rotating the same way i will beuploading photos during the build
thanks again

Deathwish

My Feedback: (6)

I'll post what i made out of a light cover from work and junk i had laying around later. I got a video of it too

jordan gutteridge

ok thats great will look forward to seeing it

Apismelifera

Have a look at the P94 Mixer/Dual ESC from Action Electronics. A nice reliable unit.

Scroll down the page a bit, you'll see it. Click the more info button. Read all about it. A very helpful website even if you don't go that route.

http://www.action-electronics.co.uk/mixers.php

The reason for counter rotating props is they counteract propwalk. Which tends to push the back of the model sideways, causing an unintended turn. The bigger the diameter and or pitch, and speed of the model the more you notice it. You'll have to trim it out if you want straight ahead operation without using a little steering input from you all the time. It may not be much but it will be there.

Also if you have a big rudder you can get back to shore if one of your props becomes fouled with weeds. With the rudder you still have steering control. No reason to give up any functionality if you're trying to build yourself a rescue boat. No reason you cant use differential steering in combination with a rudder.

Good luck with your build. Hope to see a build thread poster right here.

Deathwish

My Feedback: (6)

Here's my little boat i made out of a light cover. The name of the boat is "The Junkyard"

Part List
Hull - Light cover from work.
Bow - Sheet of wood from peach crate from work
Stern - Block of balsa wood from hobby shop
Helipad - Part from our plastic wrap (big roll) from work
Rudder Shaft's - Broken antenna
Rudder - Brass sheet from hobby shop
Prop & Prop Shaft - Parts from old r/c boat
Motor - Off of a r/c truck (modified)
Deck - Masonite board (scrap)
Deck House - Foam block with balsa outershell (so if it sink's i can find it easy)
Smoke Stack - Men's shaver handle
Radar - From an automatic soap dispenser from work (trash)
3gram Servo - Ebay
Helicopter - From friend

Deathwish

My Feedback: (6)

the hooks on the back is for a tennis ball with a fishing line on it.

Deathwish

My Feedback: (6)

took out "The Junkyard" out today. here's a video http://www.youtube.com/watch?v=4FmoZ...ature=youtu.be