My prop shop 5 bladed korts took 80~% forward to reach speed and at 130% reverse the boat couldn't stop. Flipping them side to side made a world of difference.
Maybe the full-size ones are more efficient in one direction than the other, but all of the ones I've seen on models are about as simple as it gets. Each blade is basically a flat plate that's been twisted to perfectly match your desired pitch. Very easy to draw up in CAD, then 3d print.
Prop shop korts have a slight cup to them. Chris’s have a more symmetric profile The cup on the prop shop blades is noticeable when installed on the boat. Placing them with the cup digging in for reverse makes reverse awesome, as reverse in general is a less-ideal flow path for the thrust, so having the less-efficient profile providing thrust in the more more-efficient direction (ship moving forward) provides a good balance. I tested out the direction of rotation question on Missouri. The bottom line for that hull was any difference in acceleration was negligible. The props rotating inward at the top for reverse did suck the stern down which made that direction unacceptable. Turning was hard to judge, maybe slightly worse for top of props going out when in forward. Maybe the skegs are the reason why my results were different than Will's. I think the 5-blade props I had would make turning better if they were oriented correctly. I ran the boat like that for a bit, and the turning was not as bad as it was with the prop orientation reversed. Korts definitely offered an improvement relative to either orientation of the more-cupped 5-blade props. I'm planning to make up a spreadsheet to evaluate the videos judging performance on each maneuver - Fwd to reverse time, reverse to forward, pivot left, pivot right, left turn at speed, right turn at speed
quick video. probably not the rudder selection i'll go with, flexing the drive train View: https://www.youtube.com/watch?v=eekTU3OOEV8&feature=youtu.be
Looking very good. Really good acceleration. That turning is going to be hard to beat for a ship that size.
Decided to resheet even though balsa had minimal damage. Decided to go with the semi-circle rudders, closer pivot point to the props. Gave the overall best performance across the maneuvers. Really less of a difference between all of the rudders than I expected Sides on and painted, waterline tape tomorrow A few small things left to do, make sure all the spares are set
Beaver peaks my interest in the hobby after so many years and I jump on and take a look around. Looks like high voltage and brushed motors are all the rage nowadays. Imagine that. Nice work on the rebuild Kevin.
"All the rage" might be a bit of an oversell, but it's definitely worked well for some captains. I'm not a huge fan personally...nothing against 24v, but I'd like to avoid the "Huh, that's weird" that came with it. (for reference, @Kevin P. @Beaver and I were all running very similar brushed 24v drivetrains and mine completely ate crap. We inspected every bit of it and came to the conclusion that it's possessed. I reverted back to 12v brushless after that.) Glad to see you making an appearance @SteveT44
Hey, we figured that out. Sparks just don't like more than 24v. The Holmes hobby esc is a game changer!
Thanks Steve, good to hear from you- I actually pulled the 20v brushed during the latest refit as part of going to LiPos, but I was happy with performance.
Another refit before the ship’s 4th nationals Rebuilt the guns as all the elbows were going, shifted bow solenoids to the deck aft guns rebuilt, spaced the tips out a bit because bbs were going in the same hole The kick from the guns shooting air blanks from one barrel made the boat rock back on the table Under deck rats nest New spacer for bow sides as well new guns all around she passed the bench test, my first boat essentially ready for nats
