Bumper boat build

[ashley needhamParticipant @ashleyneedham69188]

I have created a bumper thread just in case anyone was considering making one and to answer any questions.

This was prompted by young Ray, who didn’t ask a question but mentioned something which I thought I could expand on.

First topic then is the motor mount. I didn’t go into great detail, but a few pointers.

Drilling the flat brass strip: you get a drilling template with the motor in the form of the X shaped alloy mount. Either drill through the holes or centre punch to mark. Use a 3.5mm drill and then you will have wriggle room for the 3mm screws. Be aware that the X mount is not symmetrical and you need to orient it so the motor wires go straight up through the tube.

Use preferably stainless cap head screws rather than the countersunk ones, as if using countersunk, the drilling has to be very accurate or the screws will pull on their seating.

I used a blowtorch and ordinary soft solder to attach the strip to the tube, but a soldering iron should be ok. Note that the strip is (obviously) shaped before soldering on.

Extending the wires via heat shrink soldered joints I think is preferable but you can keep the plug in joints. Soldering makes the connection more reliable is my thought.

One of our chaps used a bit of aluminium tube which he cut and peeled the end of to make a ‘one piece’ mount. Obviously you have to get an outer tube to match first.

Ashley

[ashley needhamParticipant @ashleyneedham69188]

Build assistance

[Chris EParticipant @chrise]

Ashley

Have any of your clubmates made the power pod easily removable? Probably unnecessary but, for me, desirable.

[ashley needhamParticipant @ashleyneedham69188]

Er…power pod?. The motor simply unscrews and the wires feed down the tube and it’s off.

removing the mount AND the inner tube is tricky as the top pulley is glued on. There’s no other way to easily fix the pulley on. You should never need to dismantle the drive tube.

you could I suppose make some sort of clamp for the top but that detracts from the easy-build bit!

Ashley

[Chris EParticipant @chrise]

Yes I did mean the whole assembly.

A clamp at the top is what I came up with but I had hoped for a simpler and elegant solution. Sometimes it is what it is.

[The Long BuildParticipant @thelongbuild]

Hi Ashley

Why the pulley system for the rudder and not just a normal servo arm and rod ?.

Motors and ESC arrived today, template cut and some ply from our local DIY shop purchased, and a good price as was off cuts.

[ashley needhamParticipant @ashleyneedham69188]

The reason for the pulley system is to get that near 180 degrees of motor movement, mimicking a real bumper. You need the massive manoeuvrability, and playing with a few together will show you why. Anyone with less manouverability is at a disadvantage.

Making the pulley system is dead easy, just as easy as making an ‘arm’ system…which you will have to design anyway. Using wire trace or thick nylon line and using the small electrical connectors is straightforward.

Ashley

[The Long BuildParticipant @thelongbuild]

Thanks for that.

[Ray Wood 3Participant @raywood3]

Hi Ashley,

Had a proper look at the Dodge-Em article today they are a great platform for anything , how about Daleks ??

Now that would float my boat can you imagine a fleet of them chasing K-9 ??

Towpath Talk Free paper with the mag ?? not so sure, but I suppose they float !!

Looks like a building weekend, watch this space.

Regards Ray

[The Long BuildParticipant @thelongbuild]

It's all very good this bumper boat but nowhere in the write up does it explain how to hang the metal electrical cage above the pond to power the boats without looking like Dr Emmett Brown

[ashley needhamParticipant @ashleyneedham69188]

Ray. A Dalek…what a fab idea. It’s virtually a Dalek base. It should be easy to make a lightweight top.

You could of course use the hull as a propulsive base and put all manner of things on top of it.

Sorry, I did forget the overhead electrical grid!,

Ashley

[Chris EParticipant @chrise]

Posted by The Long Build on 30/09/2022 21:59:41:

It's all very good this bumper boat but nowhere in the write up does it explain how to hang the metal electrical cage above the pond to power the boats without looking like Dr Emmett Brown

 

Skyhooks.

 

Ray

You see Dalek I see Docking Module:

Docking Module

 

or even a Sidewinder / Log Bonc

Sidewinder

 

Edited By Chris E on 01/10/2022 08:49:46

[Richard SimpsonParticipant @richardsimpson88330]

I had a look at the links Chris posted. The second one is very much worth a read. The drive mechanism is a superb piece of modelling to create the realistic drive train. I can't believe he used a dentist's drill for the bevel gear box!

[ashley needhamParticipant @ashleyneedham69188]

Like the docking module! Like the Sidewinder. Would not be keen on all the miniaturisation.

A bumper hull is virtually the first, and the bumper drive would suit the second…if the boat was a bit bigger, although there are smaller brushless motors available.

Ashley

[Chris EParticipant @chrise]

Posted by ashley needham on 01/10/2022 14:09:16:

Like the docking module! Like the Sidewinder. Would not be keen on all the miniaturisation.

A bumper hull is virtually the first, and the bumper drive would suit the second…if the boat was a bit bigger, although there are smaller brushless motors available.

Ashley

Ashley

Yes the Sidewinder was an idea for the drive rather than for the size of the model in the link.

As soon as I saw your hull I thought Docking Module.

[ashley needhamParticipant @ashleyneedham69188]

I have been flooded with a question…two, actually!

first. The motor is a 28mm outrunner. The manufacturer has put 22 at the front of the i/d numbers…no idea why as it is misleading but it IS a 28mm motor.

Second. Friction between pulley and motor tube support block. There shouldn’t be that much so a smear of grease or Vaseline should suffice. I did use a plastic washer made from a plastic milk container, the others at the pond didn’t and have no issues.

Ashley

[ashley needhamParticipant @ashleyneedham69188]

Another question concerning cutting the neoprene tube lengthways in half.

UNFORTUNATELY, I used my small bandsaw, and it was very easy. I supplied all our chaps with the pre-cut foam as well. I would do so for anyone able to visit the pond as I have spare tube available….just shout.

If using a knife, a possible method might be to make a simple jig of two strips of wood, to hold the tube straight, and run masking tape along the tube, one on one side and one on the other. Draw a line in the centre of the tape lengthways, and another on the other bit exactly opposite and using the jig to hold the tube, cut along the top and then turn over and cut the bottom using a sharp knife. It may be that sticking a bit more masking tape over the initial cut line may be helpful when cutting the reverse, to hold the tube together.

Dont see why this shouldnt work!

Ashley

[ashley needhamParticipant @ashleyneedham69188]

Just a quick top tip: If your inner and outer body combings have been made correctly ie dead upright at 90 dgrees, but they are not "tight", simply put paint, sealer or ezekote or something on the inner body combing face and that might be all you need to provide a `squeaky` fit.

AS I have just done on Derek Dalek top!

Ashley

[ashley needhamParticipant @ashleyneedham69188]

I know you are all busy building bumpers and not having any issues, but the Dalek top is massively amusing and a hit with the public.

in hindsight, a slightly smaller access hole would have enabled a better Dalek proportion (hint hint).

A pictorial Dalek build will appear soon is in a boat magazine near you, and I can provide measurements if anyone would be interested.

Ashley

[ashley needhamParticipant @ashleyneedham69188]

….very soon in fact just before Christmas! Some wonderful artwork from Richard the graphical designer chap.

Later on I might do a “show us yours” bumper thread.

Ashley

[ashley needhamParticipant @ashleyneedham69188]

A FLOOD of people (one) have been enquiring about Dalek dimensions.

I have a sketch wot I used for both types and will retrieve it and scan it as a pdf for sending out if required.

Please pm me if you feel the urgent need to build a Dalek topper to go with the masses of bumper hulls you have built.

Ashley. (Optimist)

[Ray Wood 3Participant @raywood3]

Hi Ashley,

Bought my 20 copies of the magazine yesterday, everybody in the family gets a copy (wanted or not)

My Daughter Ruth loved your Dalek article didn't give the Eventide a second look

Can't wait for Stringray !!

Regards Ray

[ashley needhamParticipant @ashleyneedham69188]

Horses for courses Ray! Younger people…novelty boats, old sossages …serious boats.

Just like the park audience.

Pleased with Stingray, quite effective for essentially a modified Tup body. Its the colours…as soon as I painted it it, at seemed to spring into life

Ashley

[ashley needhamParticipant @ashleyneedham69188]

Scanned my Dalek drawings, and they are just that, not plans my any means, and if printed on A4 paper should give a full size side view. The rest can be worked out by looking at the photos.

Ashley.

EXTERMINATE! EXTERMINATE !

[Mike JParticipant @mikej]

Hey Ashley,

Bumper boats look great fun, Barbies, Daleks, Tardis's (or Tardi?), even K9's suggested. Other toppings may be available.

Just one quick question (or 2), Does the motor/prop assembly sit in front of the support tube and pull the boat/car along azipod style or behind it and push like a conventional prop?

(2) Out of curiosity, when you were experimenting with prop size why did you go X50, X40 then S35? Why not continue the 'X' theme and go X35? I don't know the performance differences between the two profiles so am curious.

Mike

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