I just bought a O.S. 46 LA and a 11 x7 wooden prop (they didnt have any master airscrew props in that size)but I tried to put the spinner on and when I tightin it down the backplate is bowed and when I try to loosen up the prop where the backplate is normal, the prop seems to loose, what do I do and does anyone have a diagram on what order the backplate and prop and etc should go , so I know I'm not putting it on wrong

Hiya,
Not sure what the issue is with the back plate. But that is a lot of prop for a .46 LA. I run a 11X5 on my AX which has much more power than an LA.
Try a 10X6, maybe 10X7.

Some wooden props do have the blade reach back slightly behind the hub. These props aren't intended to be used with spinners, but with conical spinner nuts.

I agree, get something like a 10x6. Also make sure the curved face of the prop blades face forward.

I think the manuel calls for a 11x6-7, but I'll take a look just to make sure, I have a 10x6 master airscrew, I can put on

Yah, those recommendations are odd. Towers site shows an 11x6 or 11x7 for the .46-LA but that's too much in my opinion. Perhaps I am wrong. I even know people who run highr pitch 9" props on the .46-LA Then Tower shows a 10x6 for breaking in a .46-AX and that's the engine that should get the 11" prop. Maybe there was a mix-up or something.

fly boy2,

Is the prop touching the cutouts on the spinner cone? I can't see what would cause the backplate to bow out like that unless the cone is pushing back on the prop itself. No part of the prop should touch the cone. If the cutouts are too small, you have to enlarge them so that the prop does not touch the spinner cone. The order of installation is backplate, prop, prop washer, prop nut, then spinner cone.

Jesse

no, it will bow before i put the cone on, in fact it bows so much that the holes not line up just right

I had a si,ilar issue...actually sounds exactly the same. Take a look at the back of the back plate where it sits on the propdriver. The hole in my back plate was smaller than the outside diameter of the propdriver. I ended up filing a small (even) amount of material off the propdriver so it slid into the backplate all teh way. Didn't have a problem after that. Good luck.

Is the spinner plastic? Like it was mentioned, sometimes the hole in the backplate is too small for the crankshaft. Some spinners come with several size inserts to match the size of the shaft. If you could post a picture, we can better see the problem.

Jesse

I know exactly what you're talking about - it's happened to me on numerous occasions (not sure why). I finally quit using plastic spinners altogether, and now use aluminium ones exclusively.

Bottom line is that any spinner backplate that bows isn't going to be worth flying. Avoid that type/brand of spinner in the future. And right now, replace it with one that has an adequately strong backplate.

There are lots of plastic backplates that are designed with enough strength. The one you have obviously isn't one of those.

Hi!
The prop to use for general sport flying ...at sea-level...is a 11x6 . Remember the OS LA .46 is no powerhouse in the sense that it like to rew high, but it can turn large props. 12x4 or 12x5 is no problem if it's a slow flying high winged airplane. 10x6 is just way too small for the average sport plane using an OS LA .46.
As for a spinner. Avoid it ! at least a plastic spinner. Use a spinner nut instead!

I used the APC 11X6 with both of my .46 LAs on Up-Roars and I still have one on an old scratch built Bipe with an 11X6. I did take the time to try props in the 10 to 12 range to see what I liked, that was A big {I} and something people forget. The {I} is the pilot not the plane. Changing props makes the plane fly differently and you choose the prop that keeps the engine working in it's RPM range but makes the plane fly the way you the pilot likes. When I could find them I liked the 11X4 on my Up-Roars with the LAs, I like my planes to fly slow with as much thrust as I can get. Longer prop with less pitch= more thrust, shorter prop with more pitch= more speed. Buy some props in sizes that OS says works with that engine and give them A try to see what YOU like. Buy yourself A good spinner too.

ORIGINAL: jaka

yeah its a debonair, a spad high wing trainer, the brand is DU-BRO spinner, here is a quesion can my new .46 start with a chicken stick, even though it has never ran before or can a starter start it without a spinner or spinner nut

I doubt the problem is the spinner.

The backplate is bowing, because the thickness of the prop or hardware is not right for the setup.

There should be NO "rearward" pressure on the outside of ANY spinner what-so-ever. That is what causes "bowing".

All of the pressure should only occur on the inner part around the prop shaft.

I've seen a lot of newbies do this with thinner or thicker props installed than they should have used.

Placing a spacing washer, or using different hardware solves the problem.

e.g. a spinner with a central locking screw, may not bottom out in the central shaft holder... so the newbie overtightens it because the screw feels "loose"... what is happening is that the out part of the backplate of the spinner is moving rearward with the force, which will end up damaging it. A longer central screw might fix this...

Even the best spinners can and will bow out if they are incorrectly used, and even the worst spinners may work well if correctly set up because spinners don't really do much.... mechanically.