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No turn fins or trim tabs.
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"Discussion is an exchange of knowledge; an argument, an exchange of ignorance." Robert Quillen -
I took it out for it's first run today. It was pretty lame. I had packed too much grease into the drive unit and it was too much for it to turn. I ended up trying to run it that way for a bit. I was using an underpowered servo that would give me torque steer, and the prop was a bit much for it to push. I ended up pulling it in to check, and when I pulled the battery box off, 1 of the battery packs was un-soldered from itself and 1 of the cells was smoking. Pulled the grease excess out and ran again. Better, but still no get up and go.
I ran home and sanded down the prop, and put in a metal geared higher torque servo. When I took it back out, it worked much better. It had some nutz off the line and went fast. When I turned, the back end hopped. I think I will need turn fins to stop this. It was also very "hoppy" in the water. Mostly over small chop. I guess the added weight of the batteries did not help that much at that speed. I was also playing with the trim of the drive unit. Depending on this, it would blow out the prop or take off pretty good. I didnt get much test time. I ended up rolling it and poping the wood tray that holds the servo down. So as it stands, works good, need to stop the hopping and keep the back end planted in the corners.
If you are interested, here is a video of my brothers boat that we were testing. It is a work in progress...
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Well, after the first run I made up some turn fins for it. They keep it inline much better. Highly recommended. After a few packs, I had to call it quits. I broke the flex cable adapter that I had just bought. I will be fixing this and changing things around again. I will be moving the batteries to the rear most portion of the boat, along side of the motor. I bought a small motor mount to get some more room in there to do this. I plan on sealing up the esc and strapping it to the underside of the deck in the rear portion of the boat. Should have this up and going pretty soon and a test is not far from that. The reason for the battery move is the boat "hops" alot. It is very unstable, even in a straight line and trim does not fix it. The hull has sort of a rocker curve to it, and the batts are in the middle throwing the balance off. Though being if they are in the back, the front will stick up and the hopping will stop. Not sure if it will solve my problems or make them worse. I can only run this thing at half throttle otherwise it gets squirlly and flips. Here is a video of one of my last runs with it before the drive went.
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I would also consider trim tabs.
It's looking good, I think this is going to be a hard hull to tame due to it's shape, I'm rooting for you.
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I ran it again, with a few changes. I bought a motor mount and put it in back. I put the speed controller in the back along with the batteries. Thought being it would give the back more weight and be more stable. Didnt happen. It drove a huge wheelie and once it finally planed off, it was very twitchy. Rolled it in short order. Went back out and spun the flex shaft adapter again. I couldn't run half throttle and it would overturn. I'm thinking that the best place for the batts is laying down the center of the hull, length wise. If i make a holder running down the center, my weight will be centralized and should keep a low CG and stable as can be. Only problem with this is I will need to cut the stock battery compartment. I am not sure if I should just cut out what I need and leave the rest, or if I should gut the whole inside and glass it up. Any suggestions? That said, I am looking at putting a flex cable in the thing and eliminating the stock outdrive. I dont want to spend $20 on another adapter that will just break again. So lots of changes coming.
I am curious if there is a sweet spot with the weight in this boat or if I am fighting a loosing battle. It has a rocker to it and I'm not sure if it will ever work how I want it to. I was thinking as long as I am starting from scratch, I could cut the last stepped section of the hull off. I had heard that it helps. Not sure I want to take that step, but if it would solve my problem I would look into it.
Question, what do trim tabs do? would it keep it stable at the higher speeds? My brother has a brand new Spartan that he is running and his has them.
Here is a pic of the last set up. The ESC is tied to the top of the deck to get things to fit. I put velcro on the batteries to keep them in place, and it actually held when I flipped it. Kinda surprising.
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OK, I pulled all of the electronics out and am ready to gut it. I have some running hardware from a Pro Boat Widow Maker on its way compliments of Ebay. I picked it up for cheap. Im hoping it will hold up to this thing. I do have a question if any one knows the answer. In its stock form with the steerable out drive the prop is pretty far back behind the boat. With the new setup I have coming the prop will not be as far back. Will this affect the boat positively or negatively? Also, should I exit the hull and mount slightly below the boat, or use the stock exit at the back of the transom? Any help would be much appreciated.Comment
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Sorry it has been so long but I did get to gutting it. I glassed the whole bottom of the hull, glued the top back on, and put it back together. I got out drive parts from Hobby King as the other ones I ordered looked kind of weak. The direct drive I had in it tore itself apart after a few packs,-just like you guys told me. This set up has worked for a while now. It is pretty controllable, but not too fast. It can manage getting some air off of big waves and stays stable. I think I should try some bigger batteries, but my ESC gets pretty warm right now and Im not sure it wont burn down if I do this.
Here are some pics. What do you think?20140115_132722.jpg20140115_132741.jpg20140115_132759.jpg20140115_132833.jpgComment
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