Model No2 for New RC Modeller

[Stephen GarradParticipant @stephengarrad28964]

I made my first posting in December as a new RC modeller needing help with the electrics for the narrowboat model I was building. I had some very useful advice, especially about motors and everything works a treat. I was thinking then about the next project, a 1/ 12th lifeboat kit from Tony Green & happily Father Christmas obliged. I don’t really have any problem (so far) with the modeling but I really have no idea about the RC bit. I’ve had a read around the forum & Dave Milbourn’s electrics notes. I think I’ve learned that I don’t need tank steering so I need a mixer set up. Looking at the motor application table it seems that a pair of the 540LN I was advised for the narrowboat would be right for the lifeboat. Can someone please advise & help me with a shopping list, battery, transmitter, receiver, mixer, escs & motors & servo. Thanks.

[Stephen GarradParticipant @stephengarrad28964]

[ashley needhamParticipant @ashleyneedham69188]

Hi Stephen.

As presumably you have a radio set already why not just get another receiver for the new model?

If you don’t need tank steering then you don’t need a mixer…or at least, WHY would you need a mixer? Two low-ish power motors work quite well off one ESC, and unless you want to do party tricks on the pond, a twin rudder setup should provide all the manoeuvrability that you need.

No thoughts on the motors as I don’t know exactly how big your boat is and in any event there are a few life boat people on the forum who can advise on that!

Ashley

just looked up TG and the boats are quite big and a lifeboat specialist will have to advise on any r/c setup.

[Malcolm FraryParticipant @malcolmfrary95515]

Motor choice is dependant on which of the lifeboat kits that Tony Green offers is involved. Motor choice and the work it (they) are intended to do determines the ESC. Probably a brace of Marine Viper 15s. Not the cheapest option, but cheaper than buying a cheaper option and then going for the right one.

A hardware mixer setup in the boat does improve handling, if the transmitter can do the mixing for you that's a saving on wire in the boat. Most transmitters are capable of binding to more than one receiver, so unless it is intended to sail both boats at the same time, a new transmitter should not be needed.

[Richard SimpsonModerator @richardsimpson88330]

Stephen, As Ashley suggests it is perhaps time to seriously think about the direction you want to go with your radio set up as now might be a good time to decide to invest if you think you are going to have more models in the future.

I will assume that you have a transmitter for the first boat and, as Ashley has said, you can simply purchase another receiver for the new boat. There may be a challenge with this however if the transmitter is for a single model use only. If this is the case then you will have to reconfigure the parameters and settings in your transmitter every time you switch models, which can be a bit of a pain.

If however you go for a 2.4 Ghz transmitter that has the ability to bind to multiple receivers then you can simply switch over models in your radio set and start to control a different model. I have a Spektrum Dx6e, which can store 200 models in its memory so all my models have a Spektrum compatible receiver in them, each one specifically set up for the model it is in. It is actually so convenient that I can have two models on the water at the same time and simply switch over from one to the other to control them.

Before you start to purchase further radio sets for the new model, if you are planning on having more in the future, it might be worth considering such a set up.

[Dave Cooper 6Participant @davecooper6]

Hello again Stephen,

Just a brief comment: when at the 'beginner' end of the spectrum (you and me ?), it's easy to be seduced by the available technology.

When I go to my next boat, I'll just add another receiver on the same frequency. I do the same with my gliders.

Most of the 'clever' stuff is all done at the transmitter – but, just how clever does it need to be ? There's a lot to be said for simplicity !

Regards,

Dave C

ps If you have 2.4 Ghz, you don't even have to bother about frequencies any more

[Stephen GarradParticipant @stephengarrad28964]

Thanks very much for the replies.

To clarify a little, the lifeboat is twin propeller, single rudder 1/12th so 37 inches long. I couldn't get away with a second receiver on my existing transmitter as grandson would never have it that we could only have one boat in the water at a time.

From what I had read I understood that tank steering is using 2 sticks on the transmitter to vary the motors speeds to steer the boat with no rudder input and that it is not easy to do. I thought that a mixer set up varies the speed of the inside motor when rudder is applied.

Is my understanding so far not correct?

Are there any lifeboat specialists that can help me, its the 37ft Rother Alice Upjohn from Tony Green models that I am working on.

Thanks very much

Stephen

[Richard SimpsonModerator @richardsimpson88330]

Stephen, one of the leading experts on lifeboats, in particular your type, is Neil Howard-Pritchard, who posts on here. I would send him a PM with your questions.

Looks like you will have to buy another transmitter anyway so enjoy the shopping. If you haven't already gone down the 2.4 Ghz route I would seriously look at it. You have no concerns with interference from other modellers and, with a good quality set, can enjoy a reliable signal with a range better than your eyesight.  You and your grandson will both be able to enjoy uninterrupted sailing for as long as you wish with no concerns as regards other users.

You are correct with tank steering, the left hand stick is allocated to the left hand propeller and the right hand stick is allocated to the right hand propeller, through their respective speed controllers. They can be tricky to perfectly match for speed but the trim adjustments can be used to help and even trimming the rudder can compensate. The arrangement tends to be more popular for tugs where manoeuvrability requirements outweighs the necessity for perfect straight line running. Mixing can then be used to vary motor speeds to assist steering, which can be useful with two shafts and a single rudder as you do not have a propeller flowing directly over the rudder surface so you do not get quite the same degree of 'lift' from the rudder. This is more noticeable at slower speeds.

Basically what you are saying is correct, the 'inside' shaft slows down to assist the rudder. I even believe that taken to an extreme it can actually stop or even go astern if you set it up as such.

 

Edited By Richard Simpson on 03/02/2021 13:55:25

[Malcolm FraryParticipant @malcolmfrary95515]

In that case, the 540LNs sound about right. Top speed of the real thing was under 10mph, a bit of surplus power on the model won't do any harm, but the model going much over 3 mph won't look right.

Steering by differential throttle setting is basically tank steering, but having a mixer involved, either hardware in the boat or software in the transmitter automates the process. It does generally work a lot more smoothly than doing it by hand.

[Stephen GarradParticipant @stephengarrad28964]

Thanks Richard & Malcolm for your replies and your input. There seems to be so many options that I go round in circles. With the narrowboat I built I was able to visit the local model shop & take their advice for what electronics I needed, they were very helpful & with the advice about motors from here everything worked out very well. Grandson was well pleased. The lifeboat Is a bit more complicated I think & I cant visit the model shop so I'm in the dark about which bits to order online to achieve what we need which will all work well together. It would perhaps be a good idea to have a word with Neil Howard-Pritchard, can you please tell me how to PM him, not something I'm familiar with. You can probably tell I'm not a technical whizz.

Thanks very much,

Stephen

[Richard SimpsonModerator @richardsimpson88330]

Stephen, I have sent him a PM and asked him if he would be kind enough to make contact with you.

[neil hpParticipant @neilhp]

hi Stephen,

i have just noticed your question about running a Rother class lifeboat and what engines to use.

i have built many lifeboats in my last 25 years of classic lifeboat building.

i have designed 6 different lifeboat kits over that period of time, five of them being smaller classic lifeboats around and a little longer than the Rother.

so i'll list what i run them all on….and being a cheapskate i buy the cheapest i can on ebay.

i also run them on 12v X 3.4 or 7 amp hour Yuasa type batteries,depending on which fit in the boat.

2 x low revving 12v motors such as these motors on ebay….

Dc Motor Johnson 12 V/552 | eBay

2 x shaft couplings to suit the diameter of the motor output shaft and the propellor shaft. plenty on ebay either plastic or metal, similar to these.

model boat universal shaft coupling | eBay

2 x electronic Electronic Speed Controllers, best on the market are ACTION esc's and can be bought from Componant shop. they should have forward'reverse function and MUST be rated at 40 amp. contact iain, the company owner to discuss with him what esc is available.

Action Electronics | Component-Shop

2 x spade fuse holders [same as used in motor vehicles] these go in line on the red/positive lead from the esc's to the positive battery lead to protect the esc from too much power being taken by the motors should the propellor stall for some reason…..string or weed or plastic bags wrapped round the propellor.esc's are expensive, 20 amp fuses are not.

12V/24V STANDARD BLADE IN LINE FUSE HOLDER UP TO 30A WITH SIDE SPADE CONNECTORS | eBay

1 x 7ah battery,

NP7-12 12v 7Ah 20HR GENUINE Yuasa Lead Acid Rechargeable Battery NP6-12 | eBay

or

RMAAOSwLCdgGUXz">Power-Sonic 12V 3.4Ah Rechargeable Battery Caravan Solar Alarm Leisure PS1230 | eBay

my views are my personal choice, and is what i used on my fifferent classic lifeboats.

but this is an idea of what you need to get your model on the lake.

 

 

Edited By neil howard-pritchard on 05/02/2021 19:37:01

[neil hpParticipant @neilhp]

Could i just add to my previous message……….determin what sort of water you are sailing on eventually with your lifeboat.

if it is salt water…….forget about 2.4ghz radio…….it wont work. when i built those 3 classic lifeboats in my picture, i bought 3 brand new sets of high quality 2,4ghz radio sets, each costing close to £100 each, i sail on salt water predominantly at fleetwood and lythan st annes and new brighton……….sadly because both my models and the kits have all their radio gear including receivers below the water lines due to the sunken well decks………2,4 ghz radio transmissions will not penetrate salt water…….that is why submariners [model sailors] pay premiums for 40 mhz radio sets.

i myself sold my 3 brand new sets and reverted back to 40mhz on my lifeboats………..just an observation and only my opinion………but if you speak to any model submariner, they will tell you they use 40 meg when sailing salt or clorinated water.

[Tim RoweParticipant @timrowe83142]

I am curious Neil.

Why can't you mount your receivers above the waterline?

On 2.4ghz I am careful not to sail behind big boats or obstructions but otherwise I have no problems and sail in harbours and open waters.

Tim R

[Chris FellowsParticipant @chrisfellows72943]

And Harry and his mates in Tasmania sail on a salt water canal and I bet they use 2.4ghz?

Chris

[Malcolm FraryParticipant @malcolmfrary95515]

The aerial needs to be both above the waterline and not hiding behind anything that either absorbs or deflects radio signals. Metal and wet wood are very good at deflecting signals and or absorbing them. With a 40 or 27 MHz aerial, it is difficult to hide it all away, most of it will be "visible" to the radio signal. With very high frequencies, and their resulting short wavelengths, it is easily possible to hide the entire working length, and thus lose the signal.

Older tech radios are line of sight, but that doesn't usually matter as you need to be able to see your boat to control it anyway. 2G4 is just rather more line of sight.

My home lake (Fairhaven) is salty, being primarily filled from the Irish Sea, but the only problems that any of my club members have run into with signal loss have invariably been traced to a radio whose aerial has migrated itself down into the lower parts of the hull. And on one occasion, the use of a "park flyer" radio. On a big lake, range can be a problem, but anything more than 200 yards I can't really see what the boat is doing well enough to claim to be controlling it anyway.

[Stephen GarradParticipant @stephengarrad28964]

Thanks Neil for taking the trouble with your very comprehensive reply about what I need for the lifeboat. As I have very little experience with RC and even less understanding of it, it is good to hear from someone who has so much experience. The narrowboat I did was fairly straightforward, single prop & rudder, the lifeboat more complicated.

From what I read before & what you have told me it sounds as though you use straightforward tank steering as you do not mention mixers or rudder servo on the shopping list. Is that correct? I think I can see that on a very lightweight, fast boat it would be more difficult to control with tank steering but on a slower, bigger, heavier boat it wouldn't be so difficult. Is that right? If so a 2 channel transmitter with one esc on the left stick & the other on the right?.

Fuses, no problem, I've got holders left over from our real narrowboat.

Battery, I can make up a cardboard dummy or two if I can get the sizes to see what will fit in.

We are planning to use the boat as we do the model narrowboat on the canal behind our house & also at Saul Junction on the Gloucester & Sharpness canal, about a mile away. In the summer there's a group of chaps meet on Friday afternoons to run their models. I will go and speak to them when all this covid bother is over. I presume they are a local club. We're not planning to go on salt water so your second post wont be a problem though it seems to have stirred some interest.

Thanks again for your help Neil, I've a way to go before we are afloat but I'm really enjoying it so far.

Stephen

[neil hpParticipant @neilhp]

Posted by Tim Rowe on 06/02/2021 09:42:33:

I am curious Neil.

Why can't you mount your receivers above the waterline?

On 2.4ghz I am careful not to sail behind big boats or obstructions but otherwise I have no problems and sail in harbours and open waters.

Tim R

on the old classic lifeboats there is prescious little room because of the configuration of the usual well decks and the detail within the cabin……..the only place a receiver can sometines go is in the forward area of the cabin roof, but then again the 2,4 has a tendancy not to penetrate grp cabins, and also depending on the possition of the receiver and where one is standing, transmission signals won't penetrate or even bounce off salt water.

this was the first sail of one of mine fitted with brand new 4 channel 2.4ghz, and you can see the boat intermittantly stop and start on the video..it wasn't me. i brought the boat in and then enquired on mayhem, and someone told me to stick the receiver above waterline…….only place i could was the fore partt of the aft cabin………no change at all……so i sold all three sets and bought second hand 40mhz.

Mary Stanford, a model lifeboat – YouTube

[neil hpParticipant @neilhp]

Posted by Stephen Garrad on 06/02/2021 14:16:44:

Thanks Neil for taking the trouble with your very comprehensive reply about what I need for the lifeboat. As I have very little experience with RC and even less understanding of it, it is good to hear from someone who has so much experience. The narrowboat I did was fairly straightforward, single prop & rudder, the lifeboat more complicated.

From what I read before & what you have told me it sounds as though you use straightforward tank steering as you do not mention mixers or rudder servo on the shopping list. Is that correct? I think I can see that on a very lightweight, fast boat it would be more difficult to control with tank steering but on a slower, bigger, heavier boat it wouldn't be so difficult. Is that right? If so a 2 channel transmitter with one esc on the left stick & the other on the right?.

Fuses, no problem, I've got holders left over from our real narrowboat.

Battery, I can make up a cardboard dummy or two if I can get the sizes to see what will fit in.

We are planning to use the boat as we do the model narrowboat on the canal behind our house & also at Saul Junction on the Gloucester & Sharpness canal, about a mile away. In the summer there's a group of chaps meet on Friday afternoons to run their models. I will go and speak to them when all this covid bother is over. I presume they are a local club. We're not planning to go on salt water so your second post wont be a problem though it seems to have stirred some interest.

Thanks again for your help Neil, I've a way to go before we are afloat but I'm really enjoying it so far.

Stephen

sorry steven, forgot and ommited………no, no tank steering for me……all my boats are fitted with a servo to the rudder.

[Stephen GarradParticipant @stephengarrad28964]

Thanks very much Neil for that, I'll get ordering & speak to Iain at Component Shop next week.

Stephen.

Neil, I forgot to ask what sort of running time would you expect to get from those batteries. Thanks

Edited By Stephen Garrad on 06/02/2021 22:18:22

[neil hpParticipant @neilhp]

The boat you have bought, similar to my Liverpool class that i built some years ago, had a 7ah battery, and on conservative sailing, i could get a couple of hours from one…….the 3.4/4 ah battery i could get around 1 hour 30 minutes……….by that time i was exceedingly bored, lol.

Edited By neil howard-pritchard on 07/02/2021 02:15:45

[Stephen GarradParticipant @stephengarrad28964]

Motors ordered, thanks for your help Neil.

Stephen

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