scubyfan

Hey guys,

I am an airplane guy and am working on a scale model. However, the engine has to be placed further back, thus, the "hub" has to be extended.

Now the question: what do YOU guys use to connect the engine (from inside the boat) to the props, outisde the boat? I'm interested in u-joints and all other relevant connection methods.

Thanks in advance!

LtDoc

Scubyfan,
Think of it as a very long prop shaft. Usually a solid shaft inside a 'stuffing box' (just a tube sometimes with bearings at each end and full of grease or oil). The 'stuffing box' is what goes through the hull and provides a water seal. The prop hub connects on one end, the other end is connected to the motor shaft ('U' joints, sort of). The motor is usually tilted to 'line up' with the prop shaft. Then, there are all kinds of variations on that theme, flexible shafts, hollow shafts, 'U' joints, plastic/rubber tubing connectors and who knows what else.
- 'Doc

Zac Price

In gas, most people use a weed eater cable. Some use collets and others use the stock square end for the engine end. The other end is soldered into a feral or welded to a shaft. This allows the cable to be mounted with a curve (needs a curve not to whip) Then a 5/16 brass liner is used or a 3/8 automotive brake line with a Teflon liner is used as the stuffing tube. Doing this, you will need to grease the cable ever run.

scubyfan

Hey guys,

Thanks for the replies. Can any of you guys post pictures of the installations? Also, where can I buy such parts, like U-joints, etc.

Thanks again!

playtime56

My Feedback: (1)

scubyfan,
I think there are some short hub extenders available, maybe from Fox. Anyway, someone has them. If you are going to have to extend more than an inch, you should probably use a bearing at the front to avoid a major balance problem. Here is one possibility: Use a coupler (with the correct thread sizes) to join a shaft, then run the shaft thru a bearing (near the exit) and finally put a prop adapter on the shaft. Dumas, Hobby People or Fine Design might be sources for the coupler and shaft (maybe about a 4mm shaft?). R C Boyz has a real fine selection of bearings capable of 30,000 rpm's. Get a sealed one. Tower has at least 2 sizes of prop adapters. The bearing could be CA'd in a balsa block. A couple loc-nuts for the coupler and some threadlocker should finish it up. Kind of pain having to go all over to get supplies, but maybe you know where to get most of it in one stop. I'm in the stix and use the net for most of my supplies. Hope this helps you out.Best to ya!!
Gordy

scubyfan

Thanks, Gordy, that helps plenty!