teryn1

My Feedback: (77)

Hello, I have a Magnum/ASP 160 twin 4-stroke (same as an OS 160 twin) and the crankshaft is not long enough to screw on an APC 16x8 and the nut (the propellter alone goes to the end of the crankshaft). Any ideas or workarounds?

The Ghost

I don't know why you are having problems, I have the same motor in a Christen Eagle and the prop nut is too long. It goes through the prop and bottoms out on the spinner before the prop is tightened. I had to use a washer on the nut to get the extra room.

Cheers

Stick 40

did you get the engine new, if not someone could have cut the end off.

They make a long nut that goes down into the part that it is to hold on, not sure if its a good thing to do for our props but they do. You would have to ream out the hole bigger. and use a heavy washer. I don't think I have one, but if I come across one I will post a pic.

Remember your nut should thread onto the threads of the crank, at a depth equal to the outer diamater of the threads. Example if the threaded shaft is 1/4 inch in diamater, your nut should come into contact with 1/4 inch of threads. Do not try and thread it on just a little and try and get away with it. This is how you get max. holding power from the threads and nut.

Is there a different prop with a thiner web to it that will work?

sticks

MinnFlyer

My Feedback: (4)

Can you post a pic?

Scar

My Feedback: (3)

Mine came with that long nut that was mentioned earlier, and a big flat washer. The nut has a hex head, and is drilled for a spinner retaining screw. Under the head is about a 20mm long shaft section that just fits inside the flat washer, and is threaded internally to fit the prop drive thrads. This setup would probably accommodate a prop with a 35mm thick clamping surface.

I had to drill the prop to fit over the shank of the nut. Have had no problems.

Good luck,
Dave Olson

teryn1

My Feedback: (77)

Thanks for all the help. My goal is to put a prop nut or prop hub. But the "barrel nut" (long nut that slides inside the prop) that you guys are referring to is bulky. The one I have works but I'd like to get rid of that and put a Truturn prop nut or prop hub on it. I know I am asking for a lot but I thought i'd try.

Thanks,
Teryn

Stickbuilder

You need to get the correct nut and thrust washer. The nut is a barrel nut, with a jamb nut bolt inside. There are 3 pieces that you need. Also you will need to get a 12mm reamer to ream the prop hole. Here's the way it looks when assembled with a prop.

Bill, AMA 4720
WACO Brotherhood #1

alfredbmor

By looking the pictures I can tell that it is very weird that the shaft is that short. Let me ask you a question, in picture # 2 looks like there is still room between the prop and the flywheel, is it correct?
If there is still room there, you should use a prop reamer as Stickbuilder mentioned to get the prop flush with the flywheel.
If they are already in tight contact and still there is no room in the shaft for the nuts, then it could happen that it is extraordinary short, and you should send the engine for service (to change the crankshaft).

Regards

Alfred

alfredbmor

You can also try a Top Flite wood prop, they are thinner than the APCs.

The Ghost

Why do you need to. The orignal nuts that come with the endine protect the crank if you are worried about that. If it is for the starter you may have to have something made, as I don't know any that would fit as the nut setup is a locking nut set. If it is for mounting a spinner mine has a 2.5" spinner.

Cheers

Stickbuilder

The shaft is not short, it just uses a Barrel nut. The shank on the Barrel of the nut is about 5/8" long, and you have to ream the prop to accept the 12mm diameter of the Barrel. Look at the picture that I posted, and you can easily see how it works.

Bill, AMA 4720
WACO Brotherhood #1

Stick 40

HI,

after looking at the pic's , I wonder if the threaded end of the crank does not unscrew and become longer or shorter?????? I have seen some RC engines with a prop screw that can be unscrewed and can be replaced. If you could put two nuts on the thread and tighten them together and then try and unscrew the threaded end from the engine. DO NOT PUT ANY WRENCH ON THE BACK PLATE FOR THE PROP, you do not want to mark or distort that back plate.

Get back if you find out its removable!

sticks

Stickbuilder

Geez,

Read my original post. I have explained how the engine is set up, and what kind of prop nut is used on the 160 twin. The shaft does not unscrew for adjustment.

Bill, AMA 4720
WACO Brotherhood #1

alfredbmor

Yes it looks very different than all my single 4 stroke engines (where the shaft is longer).
But you are right Stickbuilder
By the way I have not seen any crank shaft that could be unescrewed to become longer, which engines are those?

Stickbuilder

I have not a clue, but who would want to do something like that anyway? Anyway, what I posted is the real skinny on these. If you can't get the Barrel nut, lock screw and thrust washer from Magnum, you can get them from O.S. Your local hobby shop may have a set, but be prepared, the parts are more expensive than you would expect. Don't ask me how I know.

Bill, AMA 4720
WACO Brotherhood #1

Flying freak

Jett has it

They call it a 'stud' the advantage is if you pile your engine in at a high speed you can jsut change the stud (read as get a bolt form the store and cutting the head off) much cheaper to replace ....

Also the jett comes with a prop hub not a nut changing the length fo the stud lets you compensate from very thin cabron fiber racing props to say apc racing props ....

Steven

Stickbuilder

Yeah, but Jett don't build a 160 size 4 stroke twin. Jett built a very competitive high speed 1/2A engine from machine tool stock. This is not an available option on these 160 twins.

Bill, AMA 4720
WACO Brotherhood #1

The Ghost

Bill, You are correct with the nut setup, I think Teryn wants to replace the orignal nuts with a dome nut for starting. If he just used a starter cone with a 3/4" center there would be no problem.

Cheers

Stickbuilder

Tru Turn offers an adapter jamb screw that is tapped for the spinner bolt. If you look at the picture that I posted, you will see that this is what I have on the engine in the picture. This allows the use of a spinner, and allows for the electric starter. This engine will start easily on a starter that is strong enough for the average 120. It does not like a lot of Nitro though. 10% Omega runs it well.

Bill, AMA 4720
WACO Brotherhood #1

The Ghost

Bill, they are what I got with the motor, I belive he wants on of these.

Cheers

Stickbuilder

It ain't gonna work then. If that's the shape that he wants, then a spinner for an AT-6 will work, but I don't thein that Harry Higley ever made a heavy hub for the 160.

Stick 40

Ya , thats what I was talking about. Have not seen one for years. It was just a thought, don't loose any altitude over it.