The sun shone (unlike last year), the people were happy. We sailed model boats and raced model boats and chatted about things including model boats. Everyone had a good time. That's what a hobby is about.
My results:
Slingshot - Middling. Fairly average scores today. In the last race though I was flipped over and water entered the hull. The speed control is now playing up. There is a nasty gash in the side which will make an impressive battle scar when repaired.
Plank - Hopeless. Lighting the burner took an age. Once on the water it travelled about a quarter of the way across before giving up. And I broke the chimney off by dropping the boiler when packing up. A re-think is required.
Showing posts with label Plank. Show all posts
Showing posts with label Plank. Show all posts
Sunday, June 15, 2008
KMBC open day 2008
Friday, June 13, 2008
Popping across the lake
Having passed it's trials on the pool at home, the next test for the plank is on the competition ground (water) itself.
The evening was perfect, still and warm with no-one else around. I fired up the burner, primed the engine and set the boat off. After about 10 feet it died so I retrieved it and tried again. Same result. Various attempts were made with gradually improving results.
After charring the wood with excess meths from I tried a tea light. This was OK but underpowered so it was back to the burner.
A few attempts later and success - the boat made it across the lake. OK so it was in a series of hops as the steering was rubbish and I had to keep pointing it away from the bank but it worked.
Buoyed by this, the rudder was bent around and another trip made. This helped and only one re-direct was needed. A third attempt was even better, although the model paused in the middle of the pond for about 10 minutes.
The trick seems to be to let the coil get really hot. Then prime it and don't put the plank in the water until priming pushes steam out of the coil.
I'll see on Sunday if this works for real.
The evening was perfect, still and warm with no-one else around. I fired up the burner, primed the engine and set the boat off. After about 10 feet it died so I retrieved it and tried again. Same result. Various attempts were made with gradually improving results.
After charring the wood with excess meths from I tried a tea light. This was OK but underpowered so it was back to the burner.
A few attempts later and success - the boat made it across the lake. OK so it was in a series of hops as the steering was rubbish and I had to keep pointing it away from the bank but it worked.
Buoyed by this, the rudder was bent around and another trip made. This helped and only one re-direct was needed. A third attempt was even better, although the model paused in the middle of the pond for about 10 minutes.
The trick seems to be to let the coil get really hot. Then prime it and don't put the plank in the water until priming pushes steam out of the coil.
I'll see on Sunday if this works for real.
Thursday, June 12, 2008
"Boiler"
The spirit burner/tealight/bit of firelighter power source for my plank kept blowing out in the breeze. Since I can't rely on a completely still day when sailing - the people with yachts won't thank me if my prayers are answered - so the flame had to be shielded. Of course air still needs to get in so what better than a fake boiler to do the job ?
I wasn't going to spend good money on materials and besides, I couldn't be bothered to roll something from flat so the part has been made from halfanemptycanofredbull with a brass tube chimney. Even this was to be created from drinks cans but sticking aluminium defeated me. At least I can polish it for the competition. Cutting the boiler with scissors was easy as Red Bull designed the decoration to have a nice horizontal element in the middle for model makers to follow.
On the water this all seems to work well. Using a firelighter gives the best effect with real smoke emerging. The can is held in place by a balsa slab with a hole cut in it. It has to go in first time though as the metal becomes too hot to hold within seconds. Perhaps I need to lag it with wood to improve the look ?
I wasn't going to spend good money on materials and besides, I couldn't be bothered to roll something from flat so the part has been made from halfanemptycanofredbull with a brass tube chimney. Even this was to be created from drinks cans but sticking aluminium defeated me. At least I can polish it for the competition. Cutting the boiler with scissors was easy as Red Bull designed the decoration to have a nice horizontal element in the middle for model makers to follow.
On the water this all seems to work well. Using a firelighter gives the best effect with real smoke emerging. The can is held in place by a balsa slab with a hole cut in it. It has to go in first time though as the metal becomes too hot to hold within seconds. Perhaps I need to lag it with wood to improve the look ?
Wednesday, June 11, 2008
Motor MkII
I was happy with the original motor but felt a bit more grunt for use outdoors on the lake. Researching the subject on-line some builders use 5 coils of copper pipe and this seems to be the key to more power.
5 coils can be made from a single tube but the jets have to be made separately. As it happens this suited me as they now run through the plank itself and support the coil.
The heating element also needed refining. The first plan was to use a tealight candle. While this works it's a bit weak for the amount of copper involved now, Dropping a bit of firelighter into the used aluminum holder sorted this but that doesn't last very long.
Finally I've nicked an idea from a web site and made a burner up from a plumbing fitting. The fuel is still up for debate as meths works but I'm wondering if lamp oil will last longer.
Whatever else happens, on the pool the vessel certainly works. Once the coil warms up properly it's got a surprising amount of speed !
5 coils can be made from a single tube but the jets have to be made separately. As it happens this suited me as they now run through the plank itself and support the coil.
The heating element also needed refining. The first plan was to use a tealight candle. While this works it's a bit weak for the amount of copper involved now, Dropping a bit of firelighter into the used aluminum holder sorted this but that doesn't last very long.
Finally I've nicked an idea from a web site and made a burner up from a plumbing fitting. The fuel is still up for debate as meths works but I'm wondering if lamp oil will last longer.
Whatever else happens, on the pool the vessel certainly works. Once the coil warms up properly it's got a surprising amount of speed !
Tuesday, June 10, 2008
Plank
At the weekend I plan to enter the KMBC Plank sailing competition. The aim is to sail your plank from one side of our lake to the other. Power to to be provided by something other than an electric motor and battery.
For my attempt, I'm using a Pulsating Water Engine. It's old technology but fun. The engine is made of a bent copper tube warmed over a candle. Since I've not built one before I prototyped the device using a singe bit of tubing fitted to the hull with drawing pins.
Once I'd learnt that you have to fill the tube with water (prime in technical parlance) the craft worked pretty well, scooting across the bath at a reasonable speed. The tea-light lasted well so I reckon it will do for the trip on the lake. Some sort of shield will be needed to cope with the wind though.
A new more powerful engine is under construction and I'll be testing this soon.
Sunday, February 17, 2008
Plank racing
Every year the Kinghtcote Model Boat Club holds a competition. A couple of years ago it was Tomkat racing, at which I was hopeless. Then we added Slingshot racing, which I won after a slow start.
This year, it’s plank racing. You can read the (hilarious) details here – go on, the rest of this stuff doesn’t make any sense if you don’t !
Plank racing is more of a “Great Egg Race” style challenge than an out and out racing series and all the better for it. Who needs to hurtle round in circles when ingenuity and model making skills can be brought to bear ?
To my mind there are two parts to the challenge:
Get the plank across the lake.
Hit the target on the other side.
I’ve been pondering on these and have come up with the few options, for the power bit at least.
Option one turned up while browsing in Maplin last weekend. Incidentally, aren’t Maplin shops turning into a nice replacement for the Tandy (Radio Shack for US readers) stores of years ago ? Just what the world needs, a high street store where you can buy a transistor off the shelf…
Anyway, option 1 is an air engine (if you are wondering why I don’t use an electric motor, go back and read the rules, I told you it wouldn’t make sense otherwise) from the Science Museum. It’s meant to blow along a four wheeled chassis loosely described as a car. What you get is the contraption in the photo and a pump. Filling the tank with air and then flicking the propeller gives about 20 seconds of thrust along with a sound very similar to an IC engine.
This is a really impressive bit of kit. I think I can put a boat propeller on in place of the aircraft one – it will be more efficient at driving the plank and the tank capacity need to go up. A large pop bottle was the obvious idea but I think replacing the end of the current one with a long balloon might be better. That way the pressure stays up as the air supply drops.
And just as I start fooling about with this, the BBC reports that someone is making air powered cars. Perhaps I can refit my Type 2 ?
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