Topic: servo travel - control (Read 9541 times)

tt1 · « **on:** August 19, 2011, 04:52:08 pm »

Hi to all, am about to start on a Dave Metcalfe Alice Upjohn kit, and have two questions which I hope someone can advise me on.

1) The rudder servo has to have travel restrictions in both directions due to inherent design, I am hoping to buy and use a Planet 5 TX - will this permit servo adjustment or do I have to take another route?

2) Secondly, because of the boats' poor steering ability due to the limitation of rudder throw, can you advise whether to go 'tank steering' using 2 esc's and independent motor control or would a mixer (from a well known forum member and trader!

) give equivalent or better steering control?

I realise opinion will differ, but please throw some in - be a little gentle though - still very much a novice!

Kind regards, Tony.

Timo2 · « **Reply #1 on:** August 19, 2011, 04:57:07 pm »

Hi Tony

Only 1 answer to the question P94

timo2

unbuiltnautilus · « **Reply #2 on:** August 19, 2011, 05:05:12 pm »

Or.... Servo Morph for steering reduction, I think?!

pugwash · « **Reply #3 on:** August 19, 2011, 05:07:21 pm »

Hi Tony I went the P94 route as well on my current build - it appears very manoeverable

Geoff

Martin (Admin) · « **Reply #4 on:** August 19, 2011, 05:09:25 pm »

1. A Planet 5 won't do but one of those "computerised" transmitters will have option call "End point adjustment"

2. A mixer for twin motors is always better... unless you're really good on the sticks!

As Timo2 says, have a look at the ACTion 'Servo Morph ' and their mixers, twin motor controllers etc. http://www.action-electronics.co.uk/

DickyD · « **Reply #5 on:** August 19, 2011, 05:19:47 pm »

P94 Tony, I have one in my Sentinel and one in my Alkubar.

The only way to go.

johno 52-11 · « **Reply #6 on:** August 19, 2011, 05:23:03 pm »

The thing about a twin screw single rudder boat like the Rother is that to turn you need to power the inside motor and shut down the outside motor. This is opposite to what you would do with a twin screw twin rudder boat like the Arun where you need to shutdown the inside motor to aid in the turn. It’s all to do with prop wash over the rudder. This can be done with a mixer but you have to wire you the speed controller’s opposite to a normal setup.

triumphjon · « **Reply #7 on:** August 19, 2011, 10:27:23 pm »

although a planet t5 wont allow mixing the computer six channel planet set will , along with adjustabe end points !

john44 · « **Reply #8 on:** August 20, 2011, 11:34:21 am »

The planetT 5 will not allow end point adjustment but you can control the left motor with the left stick and the right motor with
the right stick which will do away with the mixer. The rudder adjustment is done through the servo-rudder linkage.
It is on my Alice Upjohn anyway.

on the build make the rudder post in two halves,IE a female square section attached to the tiller, & a male square section
fitted to the rudder, inserted and fixed with a small pin or cotter.
The reason being that after a lake collision (by another boat ) my rudder got damaged and it was a big job to sort out.
With the mod it will be easy if it happens again.

john

tt1 · « **Reply #9 on:** August 20, 2011, 05:16:22 pm »

Thanks very much for your input gents, P94 I think it will be then esp as it removes the need for two esc's making it more cost effective, but now there's more!-------------
Re John 52-11's point must admit to being a little confused re motor control, I intend using L/H and R/H props but re the rotation I'm not sure which way to go - should (looking at the stern) the left hand prop rotate clockwise and the right hand anticlockwise so both props turn inboard or vice versa? I have read on here somewhere that this can make a difference, initially I would use the mixer at 100% mode.
Re unbuiltnautilus and Triumphjohn's points, the new Planet twister could well be favourite but am wary of buying something that may be a little more complicated than my grey cells can handle!

haven't found anything re 'servo morph' yet but will keep searching.

John 44, like the idea, any chance of a pic please?

Thanks again for replies, any more info will as always be appreciated, Kind regards, Tony.

barriew · « **Reply #10 on:** August 20, 2011, 05:56:55 pm »

Here is the PDF explaining Action's Servomorph. One of the many things it can be made to do is limit the servo travel.

Barrie

http://www.action-electronics.co.uk/pdfs/P96.pdf

Timo2 · « **Reply #11 on:** August 20, 2011, 06:18:04 pm »

Hi

There is more

have a look at http://www.action-electronics.co.uk/pdfs/Twins%20Ver2.pdf

Timo2

tt1 · « **Reply #12 on:** August 20, 2011, 06:50:58 pm »

Thanks barrie and Timo2

ZZ56 · « **Reply #13 on:** August 22, 2011, 11:15:03 pm »

Quote from: johno 52-11 on August 19, 2011, 05:23:03 pm

The thing about a twin screw single rudder boat like the Rother is that to turn you need to power the inside motor and shut down the outside motor. This is opposite to what you would do with a twin screw twin rudder boat like the Arun where you need to shutdown the inside motor to aid in the turn. It’s all to do with prop wash over the rudder. This can be done with a mixer but you have to wire you the speed controller’s opposite to a normal setup.

Is this unique to a lifeboat with props in tunnels, or does it apply to any twin-screw single rudder boat (like an Imara)?

Timo2 · « **Reply #14 on:** August 23, 2011, 12:21:46 am »

Hi

"Imara" works magic with a P94 unit

set up with 2 = 755 motors a P94 unit power 12v SLA battery

Timo2

johno 52-11 · « **Reply #15 on:** August 23, 2011, 01:17:16 pm »

Quote from: ZZ56 on August 22, 2011, 11:15:03 pm

Is this unique to a lifeboat with props in tunnels, or does it apply to any twin-screw single rudder boat (like an Imara)?

I'm only aware of it from lifeboats but it could well be the case with other twin screw single rudder boats. It all depends on how the rudder deflects the prop wash.

The thing with using a mixer in this situation is you need it to work the opposite in forward and the normal way in reverse as there is no prop wash over the rudder in reverse.

Timo2 · « **Reply #16 on:** August 23, 2011, 02:12:19 pm »

Hi Johno & All

Please read P94 setup PDF and all will become clear : -

http://www.action-electronics.co.uk/pdfs/P94.pdf

Timo2

P.S. Set in Mode 3

johno 52-11 · « **Reply #17 on:** August 23, 2011, 04:33:30 pm »

Timo2

Using that mixer in that mode would give you the ability to turn the boat but would do it by the props alone and on a Rother the props are in tunnels alongside the keel and would be extremely inefficient as there would be little or no flow of water over the rudder. By shutting down the outside motor and powering the inside motor you have all the prop wash going against the rudder pushing the stern of the boat round.

The best way to control a boat like this is with a twin stick transmitter like the F14 Navy and use the mixer that is between the operator’s ears.

I used to sail on a yacht that was the opposite, Twin Rudders and a single prop. It was a great setup for sailing as you always had a rudder in the water even when the boat healed up. But get it in a marina on the motor and it was next to useless as the wash off the prop was not going over the rudders but between them.

Timo2 · « **Reply #18 on:** August 23, 2011, 06:02:20 pm »

Hi all

Boat like the Rother / Lifeboats spend 95% for there running time in the forward direction , low speed docking with mixer unit will still look good.

Cost : - ACTion Mixer P94 = £ 79.00 less Mayhem Discount

Robbe F14 Basic Radio £ 219.99 , Plus Twin stick Unit £ 99.99 ( £ 319.98 Load of money )

Timo2

colin-d · « **Reply #19 on:** August 23, 2011, 06:43:42 pm »

fully agree with all Timo's.... answers...

a P94 is the best way to go about this... i use one my self in the HMS Inflexible... (build thread on this forum)

the rudder movement can be restricted by using the outer most holes on the rudder and the inner most hole on the servo horns (tiller arm)

ZZ56 · « **Reply #20 on:** August 23, 2011, 07:56:08 pm »

Both the ACTion P94 and the unit I have can operate as two independent speed controllers, so it's worth buying anyways. I only have a 2ch radio at the moment, though, and that means having to use the mixed mode until my birthday or Christmas rolls around.

tt1 · « **Reply #21 on:** August 24, 2011, 12:29:22 am »

Thanks to all responders for some interesting info which has been useful in helping me decide the way to go

.
Re your point of servo throw limitation Colin-d, I gather that John 44 made a similar point in his earlier posting so thanks to you both for that.

Regards to all, Tony.

john44 · « **Reply #22 on:** August 28, 2011, 05:24:23 pm »

Hi Tony , here is the Rudder assy mod for my Alice Upjohn boat.

tt1 · « **Reply #23 on:** August 28, 2011, 06:26:18 pm »

Thanks very much John, really appreciated.

Hope you don't mind if a few more questions were to follow! anything you can add re the prop rotation? i.e. R/H and L/H props? rotating inboard, outboard or even two equal handed props going the same way? Have enjoyed this thread and read much more using the forum search - there seems to be no definitive ruling which I can fully understand but as you have built this boat it will be helpful and interesting to know what you did and how she performs. 35mm 3 blade is what was advised.

Thanks again and kind regards, Tony.

john44 · « **Reply #24 on:** August 28, 2011, 07:36:46 pm »

Hi Tony, I run 2 speed 600 turbo motors turning 3 blade L/H & R/H 35mm props viewed from the stern the R/H goes on the left
& the L/Hand goes on the right making inboard running propellers on a 12v lead acid.
You will be better using 2 sticks or a mixer to steer rather than just the rudder
because they are not very responsive on just rudder control, especially in reverse.
I know this point was discussed earlier but it is an important one if you are to be satisfied with her performance.

john

News:

Author Topic: servo travel - control (Read 9541 times)

Timo2

pugwash

triumphjon

john44

Timo2

ZZ56

Timo2

Timo2

Timo2

colin-d

ZZ56

john44

john44