The boat is up and running. It's come out 1.6kg lighter than another of the same hull model, and is behaving very differently, so I've got some ground work to do before judgement is made on the steering.
At the moment it's behaving like the existing boat steering wise, too little steering at low speeds and too much at high. I use dual rate and exponential settings to overcome that on that one, but my freehand design here allows 28 degrees each side of rudder movement which is fine for port turns at idle but less so for stbd, for some reason. So a bit of throttle squares things up but a bit more rudder in the water won't go amiss. At higher speeds 28 degrees is way too much, of course. Add the directed thrust and my existing boat turns within two boat lengths at full speed on perhaps 15 degrees of rudder, this one is nuts in comparison, more like a jet boat! Just spinning out.
So the next trial will have the boat better setup on the basics, and I'll fit slightly longer but thinner rudder blades with no balancing and probably parallel shaped.
Prior to all of this the cowling had to be fully fitted, which included an exhaust setup which exited the scale position with injected water. I've got pictures and video but not had the time to get them uploaded etc. I'll catch up with that, but basically the exhaust tuned pipe enters the outboard cowling and the outlet is directed into a partially sealed pipe which is three times the cross section, water injected at the top of an 's' bend cools the pipe and more importantly takes a bit of the crack out of the exhaust note. The partial sealing comes from a ring of silicone tubing that acts as a mechanical buffer between the tuned pipe and the extender. The idea sought is that extending the pipe does not effect the tuned pipe's operation and it that respect it seems to be fine so far. It's made from two rc car exhaust manifolds, one bonded in to the exit and the other fitted using an exhaust spring so that it can be pulled out of the way. This allowed me to avoid cutting a split on the cowling top to feed it over the pipe, hence is stronger. The only issue with this is that the scale like outlet is slightly forward of the steering clevises, so I was treated to a smeechy mess to clean up, that'll have to be sorted further down the line.
Cooling water outlets fitted to the lower cowling are slash cut angled tubes hot rod style ' ish. This is just a way of partially hiding the outlets because some outlet positions look a bit silly in respect to scale looks, here the water is lost in the spray at the back of the boat but a close pass allows my deteriorating eyesight to check all is well with the cooling flow.
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Topic: Dummy Outboard idea (Read 14111 times)