seehuusen
Posts: 275
Score: 100 Joined: 1/12/2012 Last Login: 4/30/2013 From: Sunshine Coast, AUSTRALIA Status: offline
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quote:
ORIGINAL: spektrumFlux do kindly correct me if my understanding is incorrect for the following... suggested motor kv for each types of Lipo. 2S : 3900~4450 kv Inrunner/Outrunner Motor 3S : 2900~3600 kv Inrunner/Outrunner Motor 4S : 2600~ kv Inrunner/Outrunner Motor 2S*3900 kv = 7.4*3900 = 28860 rpm 3S*3900 kv = 11.1*3900 = 43290 rpm (is it too high rpm to cause motor overheat rapidly) what is the ideal rpm range for motor? Correct with your calculations, you've got the KV right  What I think you might be forgetting, is the theoretical value - real world descrephancies You should allow for about 20% loss in RPM So, 3900 x 11.1 x 0.80 = 34.632RPM In my oppinion, the 3900KV motor that I have in my current boat, is a bit too fast, and asa such, I've tuned the "punch" with which it comes on, about 20% down... The new motor I found, should be right in the sweet spot RPM wise, with a bit more torque quote:
ORIGINAL: spektrumFlux comparing Inrunner 4400kv vs Outrunner 4400kv motor, Outrunner will have more torque? what is the criteria to choose between Inrunner and Outrunner motor? Outrunner has more weight turning at a larger circle, hence it will always have more torque, comparing same specs to an in-runner I don't have any experience with an outrunner, although I'd love to try one out sometime quote:
ORIGINAL: Wheelnut 1. What is the bearing mod for and where does the bearing go? I know the bearing has less resistance and will help the electronics run cooler, but does it also help keep the water out? 2. What is the sleeve mod and what is it for? 3. What's wrong with the stock shaft? 4. What is wrong with the stock coupler? Thanks in advance for any help and remember pictures say a 1000 words Hey mate, I did this exact sleeve mod, with pics on this page or the one before?!? In order to see the picture worth a 1000 words, you must also open your eyes LMAO I had to mate... hahaha 1. Bearing mod is a new-ish mod, only done a few pages back. It replaces the rubber grommit with a solid bearing, that supports the shaft a bit more than a rubber grommet. It does the same job, keep the grease in the shaft bore, to prevent water coming into your boat 2. The sleve mod ads a pipe into the original drive shaft hole, which is just drilled through the plastic of the jet drive. With vibration and what not, this hole has a tendency to get worn a lot, allowing the shaft to vibrate. The widened shaft hole allows more water into your boat, and the vibrations gives very bad thrust out of the jet drive. ADDITIONALLY, the bigger hole, sucks air out of your hull, into the jet drive, and causes your prop to loose drive and prime... bloody annoying With the sleve in place, you can glue in a longer copper pipe, which not only assists a lot with wear and tear, it also stabilized the drive shaft, giving A LOT less vibration 3. Nothing really, but in my case, I need one that is perhaps another 2-3 mm longer, so that it fits better with my coupler 4. Again nothing, you have to drill yours, and it's made from aluminium. I get a brass one, as it's stronger, and already drilled perfectly I hope that helps, I'm off to eBay to make the order for all the new parts Cheers Martin
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