SaCCaL72

My Feedback: (1)

I have heard that a nylon spinner could explode if put on my SuperTigre G-90, is this true? I have always wondered when you need to install an aluminum spinner over a nylon one. Does it depend on the RPM's of an engine or the size of an engine. I have a nylon spinner on my OS 50SX and it is running at about 13,200 RPM's or so and I haven't had a problem, what would make the SupterTigre G-90 any different running at about 10,200 RPM's or so that I would need an aluminum one? Thanks in advance for you comments...

MajorTomski

YES! they can explode!


And you use either a plastic one OR a metal one NEVER metal over plastic.

Richard L.

My Feedback: (24)

Yes, a plastic spinner can explode. Here was mine on a Saito 150:

burgh_guy61

My Feedback: (11)

I use a plastic spinner with an aluminum back plate on a supretiger 91, no problems to date. Personally i would not recommend using an all plastic spinner on anything larger than a 90 2 or 4 stroke (if i see someone with one i stay away also). I might get flamed, but i don't have any problems as previously shown.

Deadeye

I think he meant verses, not over.

I'll never use a plastic spinner on a 4 stroke, of any size. Saito 100 with 2 1/2 plastic spinner nearly killed me 3 years ago. Largest 2 stroke I have plastic on is a TH 75.

SaCCaL72

My Feedback: (1)

Thanks for your replies. Ok, I believe they can explode , but what makes them explode? Is it RPM's or Size of engine, or a user error (cutting the cone to fit a prop, screwing the cone too tight/loose, etc). I only ask because of what I said in my original post. I have always used nylon spinners to date with all my engines (OS 46AX, OS 50SX, SuperTigre 45) except my Saito 100 as it is on a Texan with a spinner nut for aesthetics. I never had one blow up and the RPM's are as high as 13,200 on my one engine. So what makes it blow up? Why was it only mentioned to me to use an aluminum spinner with my new ST G-90 and not my other engines? I don't want it to happen to me, it looks like it could be dangerous especially if it happens when on the ground... Are the spinners with the aluminum back plate and nylon cone any good or should it be an all aluminum one. Thanks again...

2slow2matter

My Feedback: (1)

With four strokes, it's the added compression and tendency to "backfire" that will make one explode. Also, the torque that they put out can literally torque the spinner into the prop, causing it to fly apart, or "explode." Four strokes are definitely harder on plastic spinners than two strokes, as two strokes tend to run "smoother". I use a plastic spinner on a saito .56 that I have, and have also used one successfully on a saito .72, but that was pushing it. I had a 3 inch plastic spinner explode on me while on the bench (breaking in a saito 1.00). That was the last time my 100 saw a plastic spinner! Almost lost an eye over that...

AllTheGoodNamesAreTaken

My Feedback: (180)

I've only seen spinners "Explode" when they are either damaged or modified by the user.
Do you forget to inspect your spinner ever time you nose-over it contacts the ground? Hairline cracks can form from even the gentlest nose over.

Are you one of those guys that slams the starter onto the spinner to start your engine?

Did you cut your prop opening with a pair of dykes?

I see all three at my field and I always wince when I see a guy run up his engine.

vicman

My Feedback: (10)

I have had them go at high RPM[:@]. So now I use aluminum for my speedy stuff.

2slow2matter

My Feedback: (1)

I assure you that my dubro 3 inch red spinner was as stock as the day it came out of the mold, and the saito 100 mangled it. Too much torque. Don't risk it. On ANY big engine, get an aluminum spinner...

SaCCaL72

My Feedback: (1)

Thanks guys, you cleared it up. It seems that torque and modification is the major culprit. I will go with an aluminum spinner with my ST G-90, seems the best way to go. I think also I will be a little more careful next time when handling and cutting(modifying) my spinners. The only thing is, is the nylon spinners almost always have to be cut to accommodate most of my APC props. I use a dremel with a sanding wheel usually to ream out the hole but it is a pain. Why don't they make them so they "Fit All"? Thanks again for all your input...

AllTheGoodNamesAreTaken

My Feedback: (180)

Four strokes are known to "back fire". This will cause the prop to contact the spinner and damage it. Torque has nothing to do with it, neither does RPM.
BUT everyone is entitled to their opinion regardless of how ludicrous it is.

YES, an aluminum spinner is by far safer than a nylon one. Nylon spinners are more fragile and cannot take the abuse like an aluminum one can. The same goes for propellers, a wooden prop is more fragile than composit or nylon ones are.

daveopam

My Feedback: (9)

The ones I have seen explode were always large diam. The last one I saw was 3" on a Saito .72. It was only turning about 9,000. I always assumed the larger ones could not handle the centrifugal force.


David

redfox435cat

They sure can. the bigger one are more prone to it.

this is why many of the plastic spinners over 3 iches are being discontinued. I think world models is the only place Ive been able to find one. Get an aluminum or corbon fiber spinner

2slow2matter

My Feedback: (1)

When you apply a lot of torque to a piece of plastic that is sandwiched between a prop and drive washer, then the plastic can very well give way. If you think that's ludicrous, then you don't understand physics. When my saito blew it's spinner, it was at full throttle--not much backfiring going on at full throttle. You sure seem to know a lot about spinners, while at the same time having questions about them in other forums.

da Rock

The spinner is always at least two pieces right......

It's often the backplate that causes the failure. The backplate takes the shock when you jam your starter onto the cone. It also tries to support the largest diameter of the cone when the rpm's go up. It takes the shock on nose overs etc. And the prop does a torque on the sucker with every backfire and every normal detonation.

So how many times have any of us ever inspected the backplate? Yeah, the cone gets a look every so often...... but..........

Take a look at the picture RichardL attached to his post. You see any more than one piece of backplate? And it's the inside (slower turning) part. The outer pieces were blasted into the ground the deepest of all the parts. And were blown the farthest from the model. And if the cone had been the piece that failed first, the backplate would have been in one piece. Richard's spinner blew up because the backplate let go.

Hey, check you back.... uh..... backplate...... check your backplate first.

AllTheGoodNamesAreTaken

My Feedback: (180)

OK then, let's agree to disagree. Based on my personal experience of flying R/C since the early 80's, I've only seen first hand spinners explode a few times. Both of those times the spinner either had been modifed by the end user or had seen a few nose overs.

I find it hard to believe that people using large 4 strokes with nylon spinners are not modifying the cut-out for the prop. I've thrown away quite a few spinners off my ASP .91 four stroke due to back-fires causing the prop to contact the spinner. I use metal spinners on my four strokes for that very reason.

If these un-modifed, un-damaged spinners are exploding why aren't there lawsuites, warnings on the packages, more forums posts, ect???

2slow2matter

My Feedback: (1)

I haven't updated my profile in a while, does that mean I don't know as much as you? Fact is, I'VE HAD A 3 INCH RED DUBRO SPINNER EXPLODE ON MY SAITO 1.00, AND MY BROTHER HAS HAD THE SAME THING HAPPEN WITH HIS SAITO 1.00.

southernlifttruck41

I have had plastic ones explode on me too. Just remimber stay out of the prop ark. When thay go thay go like a bomb...

SamD

Something to consider: http://phun.physics.virginia.edu/top...ntrifugal.html

Note that: Fc = mv2/r, where Fc = centrifugal force, m = mass, v = speed, and r = radius.

In simple terms, the bigger the spinner is, the higher the Fc. Of course, generally, as spinners get bigger, the top rpm of the engine tends to be lower- So, running that 3" spinner on a Saito 72 at 9K was probably the limit (well, it was the limit); typically, an engine that size doesn't use a 3" spinner- maybe 2.5 or 2.75.

The backplate typically interlocks with the spinner cone thus containing (reacting) the C-force working on the cone. If the backplate fails or otherwise fails to mechanically "lock" the cone, there's slim chance the cone is going to stay together once the rpm of the engine goes up. The plastic cones manage to work on the smaller engines simply because they're small diameter which- within a specific rpm range- limits the amount of C-force.

Which brings up another issue with spinners: what about the cheap, import aluminum spinners being sold? Most of these are machined from cheap, cast aluminum which doesn't exhibit the strength characteristics (allowables) of bar stock material with a specific alloy designation. From time to time I see these spinners being used and they give me the heebeejeebees (there's a mouthful) when people start tuning the high speed needle on the bench. I keep well away from these when they're being used. While expensive, the TruTurn/Vortech spinners are my choice; well made and durable.

onlyfinol

My Feedback: (9)

SamD,
Where do buy those cone? I've been looking around for a nice spiner for my P-51 PTS since it only comes with a three blade cone. I want to use a two blade prop with an aluminum cone. Is it too heavy? would it work for the Evo .46 engine?
Thanks for your response an advance!!

pie_lover123

Guys, You need to figure out that putting high-yield explosives makes the spinner explode