New to modeling!

Dickie B
Not quite sure what you mean by 'wobble' but on such a light delicate prop if one blade is giving more thrust (more pitch angle) then it will tend to flex the prop (or the shaft) as it goes round giving a wobble.

Of course if the prop is not mounted square on its shaft or the shaft is actually bent it will have exactly the same effect.

Thanks Q!

I tried my best to get the prop shaft as perpendicular to the prop spar in both planes, but I suppose that could be off.
I'm not using a "double-bearing" on the nose, so the prop shaft is only as axial to the fuselage as the rubber will make it.

should I put a pigtail bearing behind the nose bearing and see if that works? or should I just re-set the blade. I know, probably both.
If you want it right, you just gotta make it right . . .

There are several reasons for a prop to wobble:

- Prop shaft bent

- SIngle bearing

- Different incidences on the blades

- one blade heavier than the other

- Blades with different C of G - interesting one this, because in spite of the prop balancing, each blade will have a different angular momentum when it rotates (mass x distance from centre of rotation), which could cause a wobble.

I suspect in your case Dickie, it's the different angles of the blades. You can do a quick fix by bending the prop shaft so that both blades have equal incidence and see if that fixes it. If it does, you can then decide whether or not to leave as is (I would do this) or take one blade off and re-set it.

If that doesn't fix it, then it must be different C of G position. You can check this by adding weight (small piece of modelling clay) to one or other blade and see what happens. If the wobble increases, reduce the weight and/or add some to the other side.

Finally, consider fitting a double bearing.

When I read of your wobbly prop, I immediately thought of rotational mass balance versus static mass balance.
Think of the balance weights on your car wheel. They are balanced for rotation, not statically.
Of course, Andy got there first! He had the advantage of being in, while I was out, though! :evil:

Thanks guys! I'll try all of the suggestions.

Or buy a plastic one Dickie [badass]

True. A plastic one would surely work.
But then I would have someone else to blame if my plane doesn't fly! :lol:
Besides, building the planes is the best part to me . . . of course, I've never had a good flight, but that's beside the current point
I'll keep plugging away.
"The only success ever obtained on a first endeavor was from pure luck." (DBrewer)

Finished my model this weekend. Here's some pics of the progress.
This is the rudder and stabilizer, covered with condenser paper and being glued up.


This is the covered wing being set to the 4" dihedral (2" per wing).


This is the wing posts and struts with the 1/16" tilt in the front post to add the 1/8" wash-in to the left wing.


These are the little homemade tube posts.


Now, for the flight results: wait for it . . . . 2 seconds!!!! and it hit the prop and broke the spar in half . The plane did a nose-dive right out of my hand! :oops:
So I made a new one with a different design. Also, my blades were .065" thick and Williams recommends .025". So, I went with Williams' suggestion. Unfortunately, this makes the CG of the plane move, so I need to move the wing post tubes. But in the interim, I stuck some pins in the fuselage in front of the wing, and she leveled out, flew half-way around the room and hit the wall, and broke the front bearing off. Oh well, I'll fix that tonight and try again.
So I guess my top flight time is about 6-7 seconds, but it is an improvement over flight #1!

When the model hits the wall, and the wall falls down - you have a weight problem - or termites! :evil: