Hi. I'm setting up a Kyosho trainer. I've installed a Super Tigre ABC 45. Just wondering if I really need a spinner over the prop or can I get away with not having one.
Thanks
Xactibu

The engine won't mind of there's no spinner and the airplane won't mind either.

[The following was apparently my mistake: probably remembering the pointy-nose restriction for contest sailplanes. Sorry 'bout that...] Here in the states, our AMA national organization requires us to use one for the safety of people or things that might get hit by a misbehaving airplane, but unless you've got some regulation like that where you fly, I would think it's up to you.

Can you show me where you came up with this idea? I've never heard of it before.

Lemme check -- I'd love to think I was mistaken...

people said that at our field too... I could never find it... not saying yet that it isn't a rule...I just could never find it...



also...a spinner makes it a bit easier to start (if you are using a starter)

Last I heard, ama requires a spinner OR saftey nut on the shaft. Saftey nuts r fine. They're much more convient and if your not worried about looks, or the bit of lost preformance from the center of the prop being exposed, r a good option. Apperantly a while back there was a accident at a pylon race and a out of control plane killed a spectature by hitting him in the head with the shaft. That's when AMA made the rule. Or atleast that's what I heard. If u ask me, a pylon racer hits u in the head, i'm not sure what kinda differance a saftey nut or a bear shaft is gonna make.
-John

OK, just checked the rules and I don't find any such requirement for prop powered planes, though I was sure it was there somewhere...

For fast movers (i.e. sailplanes) there is a minimum nose radius spec in the contest rules (min radius = 7.5mm). Sorry if I led anybody astray.

I'm not saying the rule doesn't exist but I have not heard of it before. If anyone finds it in print, let us know. Provide sources.

Yes, please do -- and thanks for pointing it out Bruce.

Hmmm... I haven't been able to find it either! I just e-mailed on of the ama's member ppl, and I'm waiting to see what they say. Interestiung. I wish I could remember where I read it in the first place.
-John

I have seen this question before, so I did a search for "Spinners" and came up with this;

Optimum range of spinner size is 20% - 25% of the prop diameter the advantages of using a spinner , the spinner eliminates the drag on the engine from the propeller root-transition zone, where little lift, but lots of drag is produced. The engine will actually rev a bit higher & make a bit more power when equipped with a properly sized spinner .

There are a couple of rules:

The prop blades shouldn't touch the sides of the spinner , or the rubbing/vibration could make either, or both, the spinner & prop fail.

A spinner shouldn't be larger than ~ 25% of the diameter of the prop blades, or you will start to lose prop efficiency -- eg. a 3" spinner is about as big as you want to put on a 12" prop. That isn't cast in stone, but it is a reasonable max size relationship.

Have a look at these links for extra information.

http://www.rcuniverse.com/forum/m_34...tm.htm#3497546

http://www.rcuniverse.com/forum/m_39...tm.htm#3923950

http://www.rcuniverse.com/forum/m_25...tm.htm#2583467

I believe you will find these rules in contests. Not for regular flying.

Micheal

They may also be "Club" rules.

I'm pretty sure that they did have the rule some years back, but haven't gotten a rule book from AMA in years.

But to answer the question, do you need a spinner?

I'd say yeah, a beginner "needs" a spinner for a good reason. An electric starter cone fits and holds to a spinner a LOT better and safer. I've seen beginners slip off "naked" props with their starters and break the prop with the starter. And been tickled that the prop broke on the starter and not their hand.

The AMAspinner rule is in the competition rules, and not in general regulations as far as I can tell


http://www.modelaircraft.org/comp/05...ok/scale05.pdf
On page 163
2.4. All planes entered must have rounded prop spinners or some sort of safety cover on the end of the propeller shaft (such as a rounded “acorn nut’’).




It’s also on page 197, in the RC Combat section
http://www.modelaircraft.org/comp/05...k/rccombat.pdf

Well over in australia I have never heard of such a rule.

You don't need a spinner either, I learn't to fly on a plane with out a spinner.

Having a spinner just makes it easier to start with a 12v starter and in most peoples opinion make it look better. But a trainer is most likely going to get banged around and they aren't scale, hence this people care even less for looks. And as mentoined before there is some effect to the planes performance but you can't notice it.

No, you don't need a spinner but as some have said it's a bit easier if you use an electric starter although my ST45 is very easy to hand start (that's with zero nitro fuel too ). One thing to watch for though if you don't use a spinner is that the CG doesn't move back too far.

AMA rules regarding spinner nuts etc don't apply to us in Australia unless local club rules cover things like that although I've never heard of any club doing that.

Thank you to everyone for all of your info and suggestions. I'll save myself the expense of a spinner until/if I get an electric starter. Until then I'll start with a chicken stick as I've been told the Super Tigre engines are quite easy to start by hand. Thanks again. Xactibu

There is one definte advantage to using a spinner... when the prop is kicked loose because your prop nut wasn't quite tight enough, the spinner will make it easier to find the propwasher and prop nut... they'll be inside the spinner.... instead of lying around in the grass.... somwhere.

I've heard of it, but every time I've gone looking for it, I couldn't find it.

Hi!
Newcomers should stay away from spinners...at least from cheap plastic ones.
Tru Turn aluminum spinners are OK but for a newcomer it's overkill.
A much better solution for both newcomer and adwanced fliers is to use a aluminum spinner nut.

Regards!
Jan K
Sweden

See links in Post # 15

A spinner on a scale Piper Cub just looks wrong. All my engines ran fine without spinners. If I use them, it's because the appearence of the plane demands a spinner, i.e., a P-51 without a spinner looks just as wrong as a Cub with one. Even my planes that have spinners get hand started......always. I still don't own an electric starter.

I saw those, but they don't explain why so many who have never competed think there's a spinner rule.

It's only a competition rule. I got a reply back from the ama. The rule is only for competitions. He also said the story of the accident was false.
-John