Nitro Boat assembly question

[MoPower]

Hi all, it has been quite a while since I posted last. Last season, I bought a Kyosho Air Streak with the .15 engine. I NEVER even put it together, and was hoping to do it soon before the season ends on me (again)!

I have one question about the drive line, and it does not even have to pertain to this boat in particular. When glueing in the stuffing tube, or shaft housing, I am curious as to where to position it lengthwise... Do I want the "prop's thrust" to push against the end of the stuffing tube, or do I want the shaft to push in and apply pressure to the engine? In other words, when the boat is moving in the water, do I want the thrust to act upon the stuffing tube itself to move the boat, or push the engine? The stuffing tube get's epoxied in place, and there is no strut. It is direct drive. I will try to attach a pic so you can see. The manual is not specific enough. Thanks for your advice!

[MoPower]

OK, tonight I started putting the boat together. And there is a small teflon spacer that goes on the drive shaft, and it goes between the stuffing tube and the prop. So I guess the answer would be to set u pthe boat so the thrust acts upon the drive tube, and not pushing in against the engine.

[hydroracer]

hi bud. unless you've got some sort of thrust bearing between the stuffing tube and drive dog, you want to leave a space between the dog and tube of about 1/8" to 3/16". the thrust should push on the ENGINE, not the tube. if it's a flex shaft, you'll snap your cable under load without the gap between there. if this doesn't explain, let me know... just want ya to have fun, not trouble :D good luck!

[MoPower]

Thank you Hydroracer! The shaft is a solid stainless shaft, no flex cable in THIS entry level boat. At the engine, there is a female recepticle, and at the end of the shaft, there is a "dog-bone" , kinda like what you would see on an RC car for a driveshaft. The kit comes with a teflon washer, and the directions don't show any kind of gap between the tube and prop drive dog. They do specify a "length" between the transom and the prop nut. Using this length indicated to me that there isn't a gap at the drive dog. So, in this case, the prop pushes on the drive tube, and not the engine. I think that the "dog-bone" type joint at the engine would have some excessive friction and rubbing if it pushed in there too far. When I was about the glue in the driveline, I installed all the hardware, and wrapped a layer of masking tape around the dog bone, slid it into the engine's receptacle, and that ensured that everything was ligned up. I did plenty of prep work in epoxying the drive tube in,...knowing that all thrust would be pushing on this tube to propel the boat. All I can hope for is for the epoxy to hold up. The engine is mounted in a cradle, with rubber mounts.

Thanks for your thoughts, and I will post another reply after a few runs... hope the glue holds!

[hydroracer]

MoPower, you hit the nail just right. put the teflon washer between the prop and tube. it sounds like they want the thrust to push on the tube while using the teflon washer as a "thrust bearing". make sure you use the washer and if they specify to use a small gap between them there, do that too. if they don't ask for a gap, slide right up to the tube, but not as to bind it up. lube the shaft before installing it into the tube. you'll want to do this every few runs. . the goal is to be friction-freeeee. :D you'll get it right! have fun!

[MoPower]

Thanks man, and good luck with your projects! :)