Quick and simple question:

I have a trainer with a .40 OS LA engine. It comes with a prop nut. I also have a spare spinner nut. Can I use the spinner nut with out the prop nut, or do I need both on the aircraft?

-Thanks

Are you talking about the brass nuts that are rounded in the front to resemble spinners? If so, no problem.

Like DB said not only are they no problem but really are preferable. Particularly when you start using a starter if not already, the spinner nut provides for a much better starter to spinner interface and are safer than using a starter on a propeller and washer/nut combination.

Great Planes and Dubro sell cone shaped ones in both brass and aluminum. These fit most starters better than the ones made to look like a Hamilton Standard propellor hub. Also they are far better than plastic spinners that can have safety issues and always develop that ugly black ring from the starter. To my way of thinking they are far more attractive with a functional machined look on any airplane that is not exact scale.

For what its worth the threads on your crankshaft are 1/4 28's

John

you only need 1 jut infront of your prop for a two stroke. whether that happens to be an spinner adapter nut, prop hub, or jsut a prop nut, they will all work.

So, let me make sure I'm understanding this right ...

I do _not_ need a prop nut if I'm using a spinner nut. Also, if I understand you right, a spinner nut replaces the actual spinner?

Thanks,
Dave

Yes to both questions

i think you are refferring to a prop hub. prop hubs are the mini-spinners that just screw on to your crankshaft. a spinner nut is the adapter to screw your spinner in

Getting into symantics and it appears what some people call one thing another person calls it something else.

This is referred to a spinner nut and I think it's what the original poster is asking he can use

http://www2.towerhobbies.com/cgi-bin...?&I=LXE158&P=0

Some people call that a prop hub but a lot of people call it a spinner nut.

Whatever you choose to call them, they sure are an improvement over plastic spinners.

Larry

what is wrong with plastic spinners??? i have seen lots of planes with them. my SD has one, but my duraplane has a spinner nut.

BTW if you use a spinner nut buy a Red/Pink Miller starter cone for your electric starter. they work extremely well. and the picture shows the back side, not the starting side.

http://www2.towerhobbies.com/cgi-bin...?&I=LXBC75&P=V

A friend of mine had two carburetors damaged when his plane went into the ground nose first, while using a small spinner nut. My plane hit the ground nose first from a height of forty feet. I had to pull the engine out of the ground where it was embedded four inches deep. No damage to the engine or carb as the large plastic spinner displaced the dirt around the carb rather than through it. I am guessing that the plastic spinner absorbed most of impact before being destroyed, thus limiting the amount of damage.

spinnersa rea good at that. a metal spinner does the same thing. the only reason i do not like plastic spinners is you get that ugly ring around where your starter cone fits.

Plenty and most particularly in the training environment and since this is the beginners forum its an appropriate place. Virtually every new trainer we see show up on a daily basis will have a plastic spinner and probably for two reasons: they are pretty when new and they are cheap.

There are three reasons not to use them:
1. They can be dangerous when improperly installed which is usually the case almost every time. I and many others have been hit by flying plastic shrapnel countless times from other peoples aircraft many times at huge distances. This is the usual result of hurried installation.

2. Spinners are a prime reason for lost flight training time. Improperly installed spinners or just a nicked prop that needs replacing (This is flight training after all) takes up a considerable time and the usual result is you will end missing out on flight time in a busy environment . I will always go on to the next student if time is consumed fooling with spinners.

3. This one is easy with out fail they always turn 'Butt Ugly' with that ring in a short time and you can buy all the different compounds or be as carefull as you can, no never mind - Butt Ugly!


The smart flyer and student will use Spinner Nuts (and thats is the proper terminology Spaceclam) every time and you know they look 'Dame Good'.

John

i did not know that was the proper term. i have never heard it that way, and it gets confusing with a spinner adapter nut.

It is interesting how common language useage for any technical term will vary with different venues. One of the more entertaining ones is terms used in full scale aviation for various manuvers and the totally differant terms used in model aviation for the very same manuvers to the point that the full scaler and the miniture scaler frequently don,t know what each other are talking about.

John

I agree that spinner problem would eat up some of your flight time. I've never ran a Prop Nut, so I cant say yay or nay. BUT, a plastic spinner vs. an aluminium on a trainer plane and a newbie on the stick.....I say plastic. Reason being is a plastic one will disperse most of the impact on a hard nose in. The result would be a broken prop and broken spinner (easily replaced). Now the aluminium spinner on the other hand will MOST likely bend the crank. Now if you look at it that way then messing around with a plastic spinner and losin' a little flight time vs. bent crank, seems obvious to me. Besides, a beginner is going to have to learn to work on puttin on a new prop every now and again. I wouldnt want to tell a beginner that he needs to do a coplet motor tear down B/C of a bent crank. Just my $.02, dont want to make anyone mad.

the plastic spinners will break apart before all the energy is released. an aluminum spinner will absorb that. if you drill holes in your backplate to lighten it and balance it, that works really well to, because that breaks away. the impact should bend your spinner, not your crankshaft because your crankshaft is made of about 5/8ths hardened aircraft grade aluminum

Thunderhead and david a Actually I do agree with you there is more risk of engine damage with a spinner nut or just a nut than a plastic spinner in a terminal arrival.

Now as a practical matter just by my own observation in the last eight years since my retirement and almost daily flight training primarily because I am one of the few who will do it in this relatively small town. The occurances of engine damage that may have been prevented by what was bolted on the crankshaft are very small and certainly not worth quitting the hobby/sport for simply because of the unavaliable instructor (which is a frequent occurance) who is constantly tied up with plastic spinners.

John

I've been in this hobby going on 13 years, flown all sorts of airplanes, and used every combination of spinners/nuts to hold the prop on. I have never had a single problem with any of them (uh oh, guess I just jinxed myself ) I perfer aluminium spinners but will use what ever looks best/scale. As for plastic spinners coming apart, like anything in this hobby (or sport if you perfer), if you don't install them right, they will fail. Make sure there is adequate space between the prop and the spinner, ALL tab/notches line up correctly, and that the spinner cone is attached to the backplate snug (watch to not strip out the back plate on the types using just machine screws).