fairey huntsman 36 inch radio gear setup.twin screw

[jerry hepburnParticipant @jerryhepburn50515]

Hi,

I have just bought a 36 inch fairey huntsman,aft cabin, 30 yrs old.

it is fitted with two 6v motors and a few wires ect, what would i need to get these running, i do already have new servoes and radio gear, so i presume i will need one or two speed controllers ???. i think i have a 4 channel reciever as well, do i need battery packs or pack ???. i do have a pack for the reciever though. any help would be great. i havnt recieved the boat yet, its being sent to me. i just thought i may get some help from here.

Thanks jerry.

[jerry hepburnParticipant @jerryhepburn50515]

[Dave MilbournParticipant @davemilbourn48782]

Jerry
There are several different ways of doing this.

1. One speed controller with the motors connected in parallel. This means that the motors will both run at the same speed and in the same direction simultaneously, controlled by one stick of the transmitter.
2. Two speed controllers connected to the same receiver output with a Y-lead. As 1 above; offers little advantage except you can use lower-rated speed controllers which may be cheaper.
3. Two speed controllers, one for each motor, connected to separate sticks on the transmitter (usually the vertical axis of each stick). This allows you to control the motors independently and use differential motor thrust to help with the steering (also known as "tank steering).
4. Two speed controllers with an electronic mixer. This automatically applies differential motor steering as you move the rudder control stick.
5. An all-in-one device which acts as speed controllers and mixer.
I suggest you read the article "Do they both go round, mister?" on the ACTion website **LINK** This website also has very many different wiring diagrams – See Basic P94 Set-Up, for example.

As far as batteries are concerned I would advise either Nickel Metal Hydride or Llthium Polymer packs. The popular sealed lead-acid type is too heavy for a performance boat like Huntsman.

Dave M

[Paul Kerr 2Participant @paulkerr2]

Very interested in the twin screw setup. I found a very old 1 3/4" =1' (42&quot MM plan by Vic Smeed (MM086) which I am currently using a a basis to redraw to 1"=1' (28&quot, and going metric at the same time (- TG for CAD!). I note that the plans indicate a twin screw setup (set at 3 9/16" centres) but the details concentrate on a large twin diesel! I intend to scale off at these centres for the model. I intend to use 2 ECS's and mixer as Dave Milbourn describes and I am toying with the idea of going brushless (I don't think reverse is necessary in this type of model – we didn't have it in the old IC days!), but that's for later.

Any thoughts, suggestions or recommendations would be most welcome. Please note, I am a wood basher, so will be building plank on frame, so no suggestions to get a GRP or styrene hull please!

Paul

[Dave MilbournParticipant @davemilbourn48782]

Paul

28" is the right length for a couple of cheap and cheerful 380 (aka Speed 400) brushed motors. **LINK** Run them on 25mm 2-blade props and 7.2v (or 2S LiPo). I have a 20" Swordsman which has one of these and goes like greased weasel-pooh. One thing you must do and that's use flexible couplings – not the U/J type. I can recommend Model Boat Bits' Microflex type **LINK** as they can take the high speeds at which these motors run without rattling themselves and the model to pieces!
If you eventually decide to try brushless motors then you'll need a couple with a similar spec as the 380 – see the performance table on the first link above. Around 2500-3000kV should work with a 2S LiPo pack.
You can't use a mixer with Forward Only speed controllers. For the 380 motors I would suggest using the 10A "Lite" version of ACTion's P94, which will take care of everything speed/direction and mixing-wise in one box about 73mm x 50mm x 28mm. One 7.2v NiMH Sub-C pack of 4600 – 5000maH (or similar spec LiPo pack) will run both motors and the receiver if you fit a separate UBEC to feed 5v to the Rx. All of this equipment is available from Component Shop.
Hope this is of some help.

Dave M

[Paul Kerr 2Participant @paulkerr2]

Dave,

Thanks for the info. I had 380's in mind, but didn't realise mixers did not work with forward only ESCs, so I'll stick to the brushed 380's. Didn't realise the extent of vibration, so I'll certainly take your advice on the Microflex couplings.

This has all been very helpful.

Paul

[Dave MilbournParticipant @davemilbourn48782]

Paul
Few folk realise that the plastic U/J couplings with brass inserts which we tend to use most of the time are designed with a maximum rotational speed of 1000RPM! The 380 motors will rev at 19,000 RPM at maximum efficiency. I have now converted completely to using flexible couplings; they are also much quieter than the other type.
From the many photos I've seen of brushless motor installations it seems that they are generally fitted with solid couplings – at least the outrunner type is.
Dave M

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