| MudmotorTalk.com https://www.mudmotortalk.com/mmt_v2/ |
|
| question about surface drive props.... https://www.mudmotortalk.com/mmt_v2/viewtopic.php?f=6&t=23605 |
Page 1 of 1 |
| Author: | bayoumonster [ Mon Oct 31, 2011 8:43 pm ] |
| Post subject: | question about surface drive props.... |
Howdy, I've been lurking for a couple of weeks here trying to learn what I could. I'm wondering how a "surface drive" prop works. It appears that my homemade 6.5hp prop will not work nearly as close to the surface as the surface drive motors that I see going down the lake. Is it about the prop, or more about the anticavitation plate? Thanks, JBJ |
|
| Author: | Quack Stackin [ Mon Oct 31, 2011 8:49 pm ] |
| Post subject: | Re: question about surface drive props.... |
True surface drives don't have cavitation plates, a surface drive prop on plane sits half way out of the water and creates more rpms than if it were completely submerged... But if you have a cavitation plate the prop shouldn't be water piercing |
|
| Author: | bayoumonster [ Mon Oct 31, 2011 8:52 pm ] |
| Post subject: | Re: question about surface drive props.... |
Indeed..... Question---how the heck does the surface drive prop do that without cavitating? Thanks, JBJ |
|
| Author: | Woodiebuster [ Mon Oct 31, 2011 8:54 pm ] |
| Post subject: | Re: question about surface drive props.... |
Some SD's do have cav. plates, but it doesn't serve the same purpose as a lt cav. plate. It is there moreless to keep the rooster-tail down and some say it makes it pull harder in the stuff. A lt prop and sd prop are totally different designs, on a larger hp Lt you can make the prop just barely break surface and gain a mph or two but it you bring it half out it drops in performance drasticly. |
|
| Author: | bayoumonster [ Mon Oct 31, 2011 9:13 pm ] |
| Post subject: | Re: question about surface drive props.... |
I googled surface drive propellers and got some good reading, but didn't fully understand it. It appears the surface drive prop may be a wee bit over my head. After reading about the "local area of nearly infinite pressure" on a normal prop when it cavitates, I'm a little fuzzy on it. I kind of understand the difference between cavitation and ventilation now, but don't see how the surface drive prop is different. I'd like to see a surface drive and normal drive prop side-by-side in person. Later, JBJ |
|
| Author: | Quack Stackin [ Mon Oct 31, 2011 9:20 pm ] |
| Post subject: | Re: question about surface drive props.... |
The SD prop is wider and has more pitch for example a mb 35 long tail runs an 11 inch wide prop and a 35 sd runs a 12.25 and has more pitch than the long tail |
|
| Author: | Woodiebuster [ Mon Oct 31, 2011 9:33 pm ] |
| Post subject: | Re: question about surface drive props.... |
not that it matters, but a 35 lt runs a low pitch 10" A sd turns a high pitch 12ish" Alot of that has to do with the gear reduction. |
|
| Author: | MaXXis85 [ Tue Nov 01, 2011 6:06 am ] |
| Post subject: | Re: question about surface drive props.... |
There is a difference between cavitation and aeration. Google those two terms. |
|
| Page 1 of 1 | All times are UTC - 6 hours |
| Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group http://www.phpbb.com/ |
|