Spinner size
01-25-2005, 05:27 PM
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RE: Spinner size
I'd get the same size that came with the kit... or just get one of the aluminum spinner/prop nuts... it will be smaller than your original plastic spinner, but won't break on you.
I think the Hobbico .40 sized planes come with a 2.25" plastic spinner...
I think the Hobbico .40 sized planes come with a 2.25" plastic spinner...
01-25-2005, 08:24 PM
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RE: Spinner size
The spinners make it easier to turn your engine over with a starter... it gives the starter cone something to center on, and smooth surface to grip on. You might get away without it, but I'd at least replace the prop nut with a spinner nut, like this one...
http://www2.towerhobbies.com/cgi-bin...&I=LXE158&P=ML
This 1/4-28 spinner nut will fit most OS engines (check your engine manual to see what size you need for your engine). You use this in place of your prop nut, and it still gives your starter a cone something to grip onto. It's made of aluminum so it won't break, even with most nose-in crashes into grass/dirt (I know from experience
), and it's not that heavy, so it shouldn't throw your CG off.
http://www2.towerhobbies.com/cgi-bin...&I=LXE158&P=ML
This 1/4-28 spinner nut will fit most OS engines (check your engine manual to see what size you need for your engine). You use this in place of your prop nut, and it still gives your starter a cone something to grip onto. It's made of aluminum so it won't break, even with most nose-in crashes into grass/dirt (I know from experience
), and it's not that heavy, so it shouldn't throw your CG off.
01-25-2005, 11:51 PM
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RE: Spinner size
I have used the exact spinner nut that is in the link above. It has been great! Just flip your starting cone around on your electric starter and you are on your way! It is much easier to install one of those spinner nuts instead of a plastic spinner. If you have a plane the needs "the look" go for an aluminum spinner and stay away from the plastic ones (balance is an issue and they can fly apart!). Aluminum spinners can be pricey $15-$80! Aluminum spinner nuts are about $7-$10.
Oh, make sure you get the right spinner nut for your engine. Look for the prop stud size and thread count ! Your engine manufacturer will have that info. Du-Bro has a list of the sizes on the back of their package as well.
Mike
Oh, make sure you get the right spinner nut for your engine. Look for the prop stud size and thread count ! Your engine manufacturer will have that info. Du-Bro has a list of the sizes on the back of their package as well.
Mike
01-26-2005, 05:32 PM
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RE: Spinner size
On a trainer, the spinner is there for several reasons. Starting and looks are two that were mentioned.
A spinner also adds a little safty, in that if the plane gets away from you, the spinner will do less damage than exposed threads. The spinner nuts linked to above are just as good, and frankly, the prop is a much bigger problem than the threads most of the time anyway.
The other bonus to a plastic spinner is that if you do a figure 9, fence post, lawn dart, or other related trick, the spinner will take some of the crash energy, and sometimes the cone actually moves back and keeps the carb from being sheard off the engine. Somtimes it reduces the dirt down the carb as well. On the other hand, with a spinner nut, an off-center 1-point touchdown results in all the forces going right to the engine crankshaft. In theory, it's easier to bend your engine's crank that way. (that said, I use spinner nuts all the time).
Now, one last thing about spinners. If you want to go fast, get a spinner that is about the size of the firewall. The spinner will smooth the airflow around the front of the plane, and reduce drag. The fastest trainer I've seen is an Alpha with a stock Evo TPS engine. But an APC 10x7 and a 3" spinner (I think it's 3", it's huge-looking, might be 2-3/4). The spinner resulted in a noticeable increase in airspeed.
A spinner also adds a little safty, in that if the plane gets away from you, the spinner will do less damage than exposed threads. The spinner nuts linked to above are just as good, and frankly, the prop is a much bigger problem than the threads most of the time anyway.
The other bonus to a plastic spinner is that if you do a figure 9, fence post, lawn dart, or other related trick, the spinner will take some of the crash energy, and sometimes the cone actually moves back and keeps the carb from being sheard off the engine. Somtimes it reduces the dirt down the carb as well. On the other hand, with a spinner nut, an off-center 1-point touchdown results in all the forces going right to the engine crankshaft. In theory, it's easier to bend your engine's crank that way. (that said, I use spinner nuts all the time).
Now, one last thing about spinners. If you want to go fast, get a spinner that is about the size of the firewall. The spinner will smooth the airflow around the front of the plane, and reduce drag. The fastest trainer I've seen is an Alpha with a stock Evo TPS engine. But an APC 10x7 and a 3" spinner (I think it's 3", it's huge-looking, might be 2-3/4). The spinner resulted in a noticeable increase in airspeed.
01-26-2005, 06:30 PM
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RE: Spinner size
Optimum range of spinner size is 20% - 25% of the prop diameter. In addition to the afformentioned 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.
