Prop

[Dominic]

Hey everyone, I'm building a Dumas Miss Circus and tried to buy a prop the other day. Unfortunately I can't seem to buy one which is already balanced. I have been recommended to use a Prather 245 or Octura X457, any advice?

Also, any ideas where I can get a balanced prop in Australia as I believe the balance process is quite involved.

Thanks,
Dominic

[RCUK John]

Quote <Also, any ideas where I can get a balanced prop in Australia as I believe the balance process is quite involved.>


No, it is not involved.
You can buy a cheap plastic Prop Balancer for as little as £6 (GBP) which is about 10$US and whatever in Oz

First sharpen then blade edges. Set up the prop on the balancer, spin it and mark the lowest blade when it stops (say 1) using a marker pen. Spin it again and see if the same blade comes to the bottom.
If it does, use a smooth file and dress the back of the blade a little. Then start the procedure again and keep on going until the blades stop in random places. It can be tedious but not expensive and can save fracturing a skeg - and I have done that with a blade that was not balanced.

[BoatDoc]

i'm pretty sure about this...check out fastelectrics.com. they are from australia, i think. i would assume they have the props you need. they also carry some nitro stuff, it's been a while since i've visited the site. RCUK john is right, it doesn't take much to balance a prop. i use a magnetic balancer that cost next to nuthin'. i think it was 12 bucks (US). balancing is worth learning, modifying is where it gets involved...and that's worth learning eventually too.

[mjmsprt40]

I doubt that you can buy pre-balanced props anywhere, unless you buy them from a friend who will sharpen and balance them for you. Get the right size prop for your boat, then get busy with your files.

[Ron Olson]

Andy Brown has them at www.cmdracing.com . Go into "Dockside" and at the left is the Prop Wall. It is updated daily with sharpened and balanced rpops from Octura, Prather and ABC. www.funrcboats.com also has them.
Go to the RCBM web site and get one of the recent back issues. Rick did a really good article on how to balance and sharpen props. Fun R/C Boats also has an online article on their site. It's really not that difficult to do once you've done one or two of them.

[Burkey1000]

Most good dealers will sharpen and ballence a prop for you at extra charge. There easy to get a hold of. :)

[engineman351]

Dominic, No one has asked what engine or motor you plan to use. Normally for eighth scale hydros you would choose a .67ci (or 11cc) nitro engine. If you are going to use 25-40% nitro fuel an Octura 1457 (lifting prop) is a good starting point. Using a X457 (non-lifting) is ok too, but will usually require a little different strut angle. If you plan on using an 'all out' or (modified) .67 engine like a new OPS or a MAC, you can probably start with a 1460 or X460. If you want to purchase a sharpened prop, you might try contacting Chris Hoffman, aka 'dasboata' thru e-bay. He does a good job. Expect to pay $40-$60 (US$) for a fully prepared prop. Sounds expensive, but consider it takes 2-4 hours of bench time to thin the blades, sharpen, and balance a prop. Mod's like back cutting or cupping or re-pitching take even more time. Also, if you do try bal/sharp yourself, and you choose a beryllium copper prop (typical Octura), you should wear a filtering/respirator type mask, especially if using a Dremel or power tool to grind'n sand. The airborne particles are dangerous to your lungs. Last, some advice on the Dumas CC hydro. Try to build it as light as you can, especially the back half. And, make sure you get the strut positioned correcty with the recommended offset. The boat will plane easier at lower speeds and go straight. Good luck. RC