Four Candles 2012

[Alan]

I'd like to say to all that I really enjoy this forum and that reading it has taken up too much of my time recently.
Also, I believe that the person who entered a mirage drive boat in the CCC last year is a member of this forum, would it be Tim O'Connor? Are you going to enter this year? And are there any other CCCers who are also HBBers who could post their adventures here?

[Jeremy]

The drill brake on these newer drills is a problem, isn't it?  Mine stops the prop and drive with a pretty nasty jolt if I let go of the drill trigger when it's running at speed - I have to remember to very slowly let the trigger out so that the prop is only spinning slowly when the brake/shaft lock engages.

When I retired I invested in a modest machine shop at home (a couple of milling machines, a bench lathe, pillar drill, bandsaw etc) as I knew I'd miss having access to a model shop and "free" machining facilities!  Best decision I ever made, although I'm not sure that "She Who Must Be Obeyed" would agree.

You're right, Timmo was the "Wallace and Gromit" impersonator in last year's CCC..................

[Paul H (admin)]

Jeremy wrote

When I retired I invested in a modest machine shop at home (a couple of milling machines, a bench lathe, pillar drill, bandsaw etc) as I knew I'd miss having access to a model shop and "free" machining facilities!  Best decision I ever made, although I'm not sure that "She Who Must Be Obeyed" would agree.

I have similar plans - what sort of space can you squeeze those machines into?

-Paul

[Timmo]

Hi Alan.

Not in the CCC this year. All spare time is devoted to completing Zelva, the boat I'm building for the Thames raid. She'll be in the ABBA show at Beale.

I do have a couple of ideas for getting a bit more speed out of the Mirage Drive cordless drill rig so it might make a showing in 2013, but I doubt it will be a real contender unless I go the whole hog and create a new hull or hulls for the job.

Looking forward to seeing your rig completed. It's looking very exciting.

Tim.

On 15 Apr 2012, at 21:04, Alan [via UK HBBR Forum] wrote:

> Also, I believe that the person who entered a mirage drive boat in the CCC last year is a member of this forum, would it be Tim O'Connor? Are you going to enter this year?

[Jeremy]

adminHBBR wrote

Jeremy wrote

When I retired I invested in a modest machine shop at home (a couple of milling machines, a bench lathe, pillar drill, bandsaw etc) as I knew I'd miss having access to a model shop and "free" machining facilities!  Best decision I ever made, although I'm not sure that "She Who Must Be Obeyed" would agree.

I have similar plans - what sort of space can you squeeze those machines into?

-Paul

I've only got a single garage, but have a narrow bench running down one long wall, with the heavy bench milling machine at one end, a working space, then the pillar drill in the middle, an 8 x 16 bench lathe and a small Taig milling machine at the other end.  The metal bandsaw/hacksaw is on castors, as is a small bench with a 10" mitre saw, so I can shift them out of the way when not needed.  The compressor sits under one end of the bench, as does an old Vax vacuum cleaner that's been plumbed-in to some drain pipe up in the roof to provide dust extract where I need it.

[Alan]

I've been trying to make a nice mechanical system to operate both drills from one bike brake lever but there are too many structural parts in the way of the mechanism so I gave up and ordered a twin cable brake lever normally used on mini-motos, I've made the levers that the cables will attach to from a plastic chopping board. Here is a picture of the wrap spring clutch that allows the the big props to freewheel when the drill brake suddenly stops the drill. The shaft is silver steel and the spring is made from the flat strip of metal that you find inside windscreen wiper rubbers. I've had them in a draw for about ten years and they have finally come in handy.

The little metal collar is necessary to stop the spring unwinding from the screw when the drill is started.

Next step is to make some rudders while I'm waiting for material for the prop shrouds to turn up; I don't think I can get away with unguarded props.

Here's a question: is it a good life or a waste of a life to spend many hours and pounds on a peculiar project that might only get used once?

[Alan]

Just logged into Gizmag, my favourite tech news site and this popped up

http://www.gizmag.com/renholz-drill-powered-trike/22186/

So the cordless canoe challenge is not the only cordless competition out there. This trike is made of wood.

[Port-Na-Storm]

Now a plywood trike like that I could get really excited about. I think I have enough bits and bobs laying around to build one.

[Jeremy]

I've been playing around with remote drill trigger operation, too.  Not too easy, I've found, as I wanted to retain a degree of sensitivity, to avoid the dreaded "thunk" as the drill chuck locks up.  I'm playing with an electrically driven remote control, which looks promising.

Rather than rudders, can't you steer by using differential thrust?  I'd have thought that running one prop forward and the other backwards would be enough to make it turn on a sixpence.

[Alan]

Are you using a servo to operate the drill, Jeremy?
I thought I'd covered every single option but I never considered differential thrust. But as I have these one way drives I can't run them in reverse anyway. Plus I've just cut all the ribs for the rudders so I'll just keep to that plan now.

[Jeremy]

I've just tested the throttle actuator and it seems to work pretty well.  I thought of using a servo, but in the end I found a geared motor in my junk box that seems to do the job more simply.  It's essentially a small DC motor with a 1250:1 reduction gearbox, that virtually locks up when not powered.  I've fitted a cam to the shaft and have found that run on 3 V it provides a nice progressive throttle with just push-button operation (one for throttle up, one for throttle down).  The motor stalls when the trigger is fully home, without exerting too much force to it, so I don't need to worry about a limit switch.  I'll post a photo over on the Duck Punt thread.

[BrianP]

That Trike really is good looking



Brian

[Alan]

The air rudders are now made, their size was dictated by the scrap of drawer base plywood I had lying around and also the size of a piece of "Profilm" heat shrink film.

The rudders are covered with heatshrink film and I did not do a very good job. I now realise that this is partly due to not continuing the rib caps all the way to the trailing edge.

In my haste to get the rudders finished I used cyanoacrylate glue and arranged fan ventilation, but not enough of it. I've just suffered about 48 hours of very unpleasant flu-like symptoms caused by my hypersensitivity to cyano, so everyone please use plenty of ventilation when using this glue. Luckily it's not much used in boatbuilding although I did come across an account of someone who built a strip planked balsa canoe with it.
Then my pillar drill motor went up in smoke (it lasted 51 years!) and it took me a few days to source, fit and wire a new one, causing a bit more delay in the build. I did a bit more today and took a picture of everything roughly assembled to show what it will look like:
 

[tony waller]

These rudders are beautifully made – takes me back to my aeromodelling days. We will all pray for no wind. Tony

[alopenboat]

On 25 Apr 2012 at 8:59, tony waller [via UK HBBR Forum] wrote:

>
>
> These rudders are beautifully made - takes me back to my aeromodelling
> days. We will all pray for no wind. Tony
>

Is sail assist allowed under the rules?

--
Hoping for calm nights

Alastair Law,      
Yeovil, England.
<http://www.little.jim.freeuk.com>          

[Paul H (admin)]

tony waller wrote

These rudders are beautifully made - takes me back to my aeromodelling days.

My exact thoughts - I have happy memories of building balsa wood gliders as a kid, that in many ways led me to building boats.

[Dennis A]

Alan

In the heats if my boat "FAST" fails to over take Four Candles, will I be able to successfully protest that your boat interfered with my progress due to the strong back draft caused by your propellers.

[Alan]

Thanks for the nice comments people.
 
I can't think of a suitably clever repost for Dennis yet, but talking of protests I did wonder if Tobias' Hilti drill was over the maximum value last year as they are not available in shops, it seems you have to apply to Hilti for a quote. But it would be rude of me to mention it.

Dennis, are you going to post some news about your entry on this forum, and show some pictures?

Today I have been sleeping on the sofa, and planning construction of aluminium prop shrouds to be curved around a plywood former.It's all adding so much weight, there might not be anyone behind me in the heats.

Finally, why were some but not all of the entries in 2011 plagued by weed, is it just random? did the deep forefoot on King Canute shield his propeller?

[Dennis A]

The 2012 CCC "Fast" has now a pointed stern.
A propeller has been made to suit the new drill ( only18v 1.5 Ah) which runs at lower revs and this year will be kept in the low speed position.
The drill is coupled directly to the curved drive shaft via a axial bearing to take out the side thrust generated by the shaft. Tests on the pedal boat have shown that the new propeller has a slip factor of approximately 20%.
The first test under power was a little disappointing and  showed a similar speed to last year 5 to 5.5 mph but the drill was running very cool.
I now plan to start the fine tuning but do not expect much of a speed increase as to go from 5 to 7 mph requires a power increase of around 70%.

[Alan]

I made one prop shroud around a plywood former and post here a picture of it mounted temporarily.
I don't like it because it is difficult and time consuming to make and requires lots of little pieces of wood and many screws to mount. Also the drill support beam and assembled shrouds do not fit in the car so much fiddly assembly is required at Beale. I may go back to the original plan A which will be two props in the water but with a Secret Plan to combat the potential problem of weed.

I've been looking forward to completing this but at the moment it feels like work without pay.