Sea Trials and tweaking
Recently the build process has been concentrating on manufacture of the detail bits and on trying to get the right motor/battery setup.
I gave it a test run with a big Johnson motor and a 12 volt NiCad pack. I have no idea of the motor size 'cause the numbers on it don't appear in the mfg web site listings. However it is a brute of a thing with two flux bands and its heavy as well. This went OK but in truth it was really a bit fast, especially on the turns and she sat a bit low at the stern.
I changed for a one size down Johnson (a single flux band) and left the battery at 12 volts. This draws around 1.5 amp free running.
A pond test proved interesting, with a slight improvement in performance but just not getting up on the plane at all (see below).
I then checked the transom flap setting (approx 1.5deg down) and twiddled the bottle screws to give around 3 degrees up.
The difference in performance was remarkable! She no longer seemed to be struggling, the break of the bow wave had moved back to around level with the main mast and the forefoot was well clear of the water.
Whoopee ........:music_too
At this setting the motor was drawing around 3 to 3.25 amps.
Further adjustment of the flap position didn't seem to improve things so it stays at 3deg up at least for the time being.
With the change of trim at high speed I'm getting water into the hull, apparently through the rudder tube. This is one of the plastic moulded ones and the rudder stock is a bit of a loose fit. Clearly a liberal application of silicon grease is not enough to make the seal given how the stern tucks in at high speed. So the next wee project will have to be a tailor made one of brass and if ingenuity makes an appearance, I'll also fit a wee stuffing box on the top end. I'll also increase the tube length a bit (3 to 4 mm) so that the rudder linkage just clears the deck beams.
The next step will be making up a new NiMH battery pack with subC cells to give me greater amperage - probably 3.9amp if I can manage it. Much will depend on the weight though.
I plan a 'saddle tank' design with the pack distributed across the hull bottom. This will give me greater scope to correct the trim by moving the pack backards or furrat.
When I get all this done, I'll start fitting the detail stuff; deliberately left off up to now for fear of damage during all the poking about in the bowels
Coming on not bad although I say so myself........
Iain