cordless airboat propeller question

Cordless Air Boat

Alan
As I have said before, a increase of 1.5 X the prop speed will make a improvement in your boat speed but could damage the batteries in your drill. What you really need is a gear system so that the prop speed could be increased in stages.
I am starting to build a planing boat for next years event.

Dennis

 

http://www.youtube.com/watch?v=J59ONjCOtU0

http://www.youtube.com/watch?v=W6YLO4Op-qs&feature=related

Wow- I wouldn't have thought you could get this speed and run time.

 

Dennis, you are right, but I'll take the risk based on gut feeling. Bntii, I had about 1/2 hour of cruising around which means that I was only using about 90w per drill cruising at full throttle which compares to 260w measured static per drill. As about 60w is absorbed by each drill with no load, thats a very small power to the prop when cruising. Even if I only cruised for 1/4 hour it is still very low power to the props, and the batteries were not flat at the end.

Anyway, a friend has bored all the toothed belt pulleys for me but I'm feeling very lethargic about this and other hobby interests at the moment so I have not done the work yet. But I'll post here when I have some results,
Alan

 

Cordless Canoe progress 2013

Hello all, I said I would get back with results of changes:
I tried designing props using Javaprop which would theoretically provide about twice as much thrust and efficiency but they were too difficult to make in the time I left myself (last minute of course). So I then built a step up belt drive speed increaser but the result was very disappointing with only about 7% increase in rpm; I think the drill might have been reaching it's power limit, don't really know why.
For this years race I went for two props in water, conventional by CCC standards, driven from long shafts. Ended up with 12" x 8" props from model 'planes but the drills were cutting out due to overload; they work again as soon as you release then pull the trigger.
Thanks for all suggestions last year.

 

Pic posted here, couldn't get into previous.

 

Thanks for the post.

Wonder if list member Jeremy participated this year and what the winning entry looked like.

Porta

 

Unfortunately I didn't have time to compete this year, we're part way through building a new home, and it's absorbing a fair bit of my free time. I may have another go next year, as I've incorporated a boat shed and workshop in to the new house..........