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Prop/thrust washer
I somehow lost two prop washers to two different engines. (Mag.91RFS and Saito 1.80FS) Can they be purchased at a hardware store? Sizes???
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RE: Prop/thrust washer
I would try a stainless fender washer. Just take your engine with you. It doesn't have to be metric but find one that fits closely to your prop shaft. If you have a buffing wheel you can make it look like chrome.
Bill |
RE: Prop/thrust washer
I would look to Fastenal and see if they have anything in a hardened washer.
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RE: Prop/thrust washer
ORIGINAL: jeffie8696 I would look to Fastenal and see if they have anything in a hardened washer. Better yet. It wouldn't be foolish to use a hardened washer. Especially if your engine is large. You might also check with a local hobby shop if you are lucky enough to have one. Bill |
RE: Prop/thrust washer
Saito 180 prop washer
http://www.horizonhobby.com/Products...ID=SAI170R3135 Magnum 91 Four Stroke http://www.hobbypeople.net/gallery/280208.asp |
RE: Prop/thrust washer
By all means, buy an original replacement from the sources w8ye referenced above. You do NOT want anything that is a sloppy fit on the threaded end of the crankshaft! That would result in a lot of vibration, or worse.
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RE: Prop/thrust washer
ORIGINAL: Ken6PPC By all means, buy an original replacement from the sources w8ye referenced above. You do NOT want anything that is a sloppy fit on the threaded end of the crankshaft! That would result in a lot of vibration, or worse. |
RE: Prop/thrust washer
ORIGINAL: Ken6PPC By all means, buy an original replacement from the sources w8ye referenced above. You do NOT want anything that is a sloppy fit on the threaded end of the crankshaft! That would result in a lot of vibration, or worse. Any washer that is the correct size will do the job If we take an extreme case of an improvised steel washer, with a thickness of 2 mm and an O/d of 30 mm; even if this washer does have a very sloppy fit on the end of the shaft (with a hole 1 mm larger in diameter than the shaft thread), the imbalance calculates to ~23.5 cubic mm of steel (specific gravity 7.8), which are 0.18 grams 1.5 cm from the center, or 0.12 grams/cm. This is equivalent to an imbalance of less than 0.006 gram at the blade-tip of a 16" prop... I don't think you can really feel such a level of vibration, at ~9,000 RPM, even if it was an electric motor spinning this prop... With any single-cylinder glow engine, which inherently suffers from a partial primary balance, this will really be imperceptible. ...So much for using expensive magnetic balancers, for props intended for such engines... |
RE: Prop/thrust washer
I use to balance all my props very thoroughly, but since I got into high performance electrics I`m not able to balance the tiny 4.1" to 5" props. They are so light-weight that they don`t move at all on my magnetic balancer, making balancing impossible. Maybe they all are perfectly balanced from the mold? I have began to just slap them on and fly, I have not experienced any problems or vibration to speak off so far. I turn these props from 28 000 rpm to 42 000 rpm static. Too little mass I think, to make a difference.
Edit: This is me flying my Zagi Typhoon 430 in the early days of development, it is faster now:) One shold think that these props would need to be balanced, but maybe they aren`t so bad to begin with. http://www.youtube.com/watch?v=N_1uW_Ix8cs Yeah, I know this isn`t glow, but I feel it fits this balacing thread somehow;) Bottom line is that I agree that a small imbalance of a small washer on the output shaft turning about 9-12K propably will not be noticed at all |
RE: Prop/thrust washer
ORIGINAL: asmund I use to balance all my props very thoroughly, but since I got into high performance electrics I`m not able to balance the tiny 4.1" to 5" props. They are so light-weight that they don`t move at all on my magnetic balancer, making balancing impossible. Maybe they all are perfectly balanced from the mold? I have began to just slap them on and fly, I have not experienced any problems or vibration to speak off so far. I turn these props from 28 000 rpm to 42 000 rpm static. Too little mass I think, to make a difference. Edit: This is me flying my Zagi Typhoon 430 in the early days of development, it is faster now:) One shold think that these props would need to be balanced, but maybe they aren`t so bad to begin with. http://www.youtube.com/watch?v=N_1uW_Ix8cs Yeah, I know this isn`t glow, but I feel it fits this balacing thread somehow;) Bottom line is that I agree that a small imbalance of a small washer on the output shaft turning about 9-12K propably will not be noticed at all FASTER NOW? Gawd. Jack Northrup would be proud. Bill |
RE: Prop/thrust washer
ORIGINAL: asmund I use to balance all my props very thoroughly, but since I got into high performance electrics I`m not able to balance the tiny 4.1" to 5" props. They are so light-weight that they don`t move at all on my magnetic balancer, making balancing impossible. Nice flying on the Typhoon, love sound of that screaming lecky. |
RE: Prop/thrust washer
Oh, thanks for that tip. I will definately try it out;)
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RE: Prop/thrust washer
Dar, you are probably correct about the washer. It isn't that big or heavy.
I was actually thinking about a situation where a friend of mine lost the crankshaft adapter for his spinner. The hole in the spinner was a little too large for the crankshaft, and it vibrated so badly he thought his engine was JUNK! When I found that the spinner was missing it's adapter, I made a new one to fit. The engine ran fine after that. However, the spinner is quite a bit heavier than a washer, and the outside edges are a lot farther away from the prop. |
RE: Prop/thrust washer
If I purchase the washers online it will be $21.20 without shipping. That's a heck of a lot of money for a couple of washers. Just wasn't sure if I could get away with using some that were not quite OEM. I'll go see if they have something like them at the hardware store.
Thanks guys. |
RE: Prop/thrust washer
ORIGINAL: cruzomatic If I purchase the washers online it will be $21.20 without shipping. That's a heck of a lot of money for a couple of washers. Just wasn't sure if I could get away with using some that were not quite OEM. I'll go see if they have something like them at the hardware store. Thanks guys. $21.20 does seem a-bit over the top though. Bill |
RE: Prop/thrust washer
Well, the $21.20 DOES include not only the washer, but also a prop nut and locking nut for both engines.
Personally, I would pay it, and try to not lose them again... |
RE: Prop/thrust washer
ORIGINAL: Ken6PPC Well, the $21.20 DOES include not only the washer, but also a prop nut and locking nut for both engines. Personally, I would pay it, and try to not lose them again... That's more like it. Bill |
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