flynfool

Is it ok to run a plastic spinner on a 4 stroke? I heard somewhere you weren't suppose to for some reason.
I have a Saito 100 on an Ultra Stick 60 and I was thinking of using a Dubro spinner on it,,,,yes or no?
Thanks,
Carl

TennCharlie

I have a Saito .91 & I can't use the lock-nut with a Spinner. It hasn't been a problem so far.
If the motor kicks backs hard enough it could be I guess.

MinnFlyer

My Feedback: (4)

Go 4 it!
Everyone I know, including me, uses plastic spinners on 4 bangers.

flynfool

thanks guys,,I just wish someone made the cutouts to fit these larger props and the APC's.
Thanks again,
Carl

Equest

Using a plastic spinner should not be a problem, go for it! Make sure to use the locknut though. This is a safe guard in case the engine backfires.

MinnFlyer

My Feedback: (4)

They have to make them small for the people who are using smaller props... You can make the hole bigger, but you can't make it smaller. This is really a very simple task if you have a dremel tool. If you don't, find a buddy that has one and bring it over to his house.

flynfool

Yes Sir, I do have dremel but it's hard to get them the same size. I haven't found a good way to do that. If you know any tricks I'ld love to hear them.
Thanks,
Carl

JCOKEEFE

My Feedback: (2)

To answer your original question, ensure that
you run your engine on the rich side. If a four
stroke is run too lean, it will kick off the prop,
including the spinner, no matter what brand.

Jerry

TerrellFlyer

Been using plastic spinners on four stroke's before Mosses had a boat,never had a problem.
Have a goodun,John.

CurtD

My Feedback: (1)

No reason not to and I've done it. You should be aware, though, of what can and DOES happen with plastic spinners on 4-strokes. 4-strokes generally have more tendency to backfire (that is, suddenly reverse it's rotation momentarily due to detonation, usually during starting). Most plastic spinners I've seen (with some notable exceptions such as CB Associates ? ) have the shell pinned to the backplate for stability. If an engine backfire causes the prop to slip on the shaft, guess what happens? You got it - the prop tries to force the spinner to turn with it. The pins try to stop the rotation but the prop usually wins and shatters or cracks the plastic shell. Now, if that has happened and you don't notice it, you might continue to try to run the engine with a cracked spinner. The result CAN be (I've seen it happen once) that pieces of the spinner suddenly part company with the rest of the airplane while people are standing close by.

If you're going to use a plastic spinner with a 4-stroke be sure you check the tightness of your propellor nut(s) often since they do have a tendency to loosen with weather/humidity changes. If you hear or feel the engine backfire while starting STOP and check to make sure the spinner has not been damaged.

pabdoc

I agree with CurtD...check the prop nut for tightness often! This Spring I was test-running a 70 Surpass with a plastic spinner, and didn't notice the prop nut had loosened except quite by accident ( now there's a pun un-intended!). Thank goodness I happened to see it before starting the engine one more time!

TennCharlie

[QUOTE]Originally posted by TennCharlie
I have a Saito .91 & I can't use the lock-nut with a Spinner. It hasn't been a problem so far.
If the motor kicks backs hard enough it could be I guess.

I knew I shouldn't have opened my big mouth. The first time I tried to crank Sunday, the Saito backfired & there went the spinner, nut & prop washer. I like to never found the washer. I put it back together with the locknut minus the spinner & had to hand crank it with a screwdriver the rest of the day. Now that was fun.
I believe it was a little lean though. I retuned it & it seemed to run fine.

tinman

My Feedback: (13)

hey hi ya charlie....good to see guys from tenn. in here! i am in the columbia club myself...anyway ya can't hardly tighten a prop nut too much. don't be afraid to lean on that wrench! -Tinman-

mtthomps

My Feedback: (2)

I don't think it is a good idea to cut the hole out bigger with a dremel. Use one of the 4 step prop reamers. They are cheap, and do the job with precision. Every one I have done with the prop reamer fits like a glove with NO freeplay.

Joss Stick

My Feedback: (1)

I think he was talking about the opening for the prop, not the shaft.

I've used plastic spinners on four strokes as long as I've had four strokes. Not a problem. If it's not a scale ship, sometimes I go one size bigger than needed to eliminate the need to carve the prop opening. Sometimes a little shaving is necessary, but not the big carving job that is most often needed with the smaller spinner.

TerrellFlyer

Hi mtthomps,how do you enlarge the spinner with a prop reamer?
Have a goodun,John.

P-51B

My Feedback: (5)

Just so everyone is aware of the power of a kickback;

I just got my first four cycle, a Saito 180. During break-in I had an 18x6 wood prop and a tru-turn spinner on it, when it kicked back.

The result was the spinner ended up halfway through the prop, and the spinner was completely ruined due to deformation.

Had this been plastic, the prop probably would have survived, but who knows what the plastic shards would have done. Plastic can shatter, metel deforms.

I switched exlusively to Aluminum spinners several years ago after watching my plastic spinners physically deform while running at high RPM (yep name brand plastic)

flynfool

Thanks guys, I used the plastic, got the cutouts to fit over the prop and then balanced it, man that was a trick,LOL, it worked great.
I had just enough thread to get the jam nut on, but I can see where it might be a problem with some spinner backplates, there ain't much shaft there after you stick that big prop on.
I have so far always hand cranked this one. I use a welding glove and flip it backwards about a quarter of a turn against compression. So far it has always started within a few flips, usually 1 or 2. If it doesn't fire on the second flip I know it's not wet enough and prime it again.
About plastic spinners deforming at high rpm, I really don't consider below 10,000 high rpm, when most 2 strokes run 12k and up.
Thanks again guys,
Carl

TennCharlie

Hi Tinman... I attended your Spring Giant Scale Fly-in in May of this year. I hope to have a giant scale bird someday. They sure are fun to watch. You may have noticed a red Goldwing motorcycle in the parking lot that Sunday. That was me.

tinman

My Feedback: (13)

yes charlie, i do remember...there was several nice bikes there...hope ya enjoyed the show! -tinman-