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Old Aug 22, 2010, 08:42 AM
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United States, MA, Medfield
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Prop Adaptor vs. Prop Saver questions

Question 1: The prop adapter I have. Looks like the OD of the threaded shaft is 3/16". If I want to use it should I drill out my props hub to 3/16" and then re-balance the props?

Question 2: I balanced the props I have then put one on the prop saver and did a test run. Ran okay but got a fair amount of vibration, especially at about 1/3 throttle. Why doesn't the prop balance on the prop saver?

Background--

I just about have my QuickStick kit almost ready.

I have some EP-1047 props for the 950kv motor and balanced them by spinning on a metal shaft slightly smaller than small hole in hub. Then adding tape as needed.

I have both a prop-saver and prop-adapter.

Haven't tried the prop-adapter, need to drill prop hub if I'm going to use it.

I balanced the props and put one on the prop saver. It was very tight pulling the band to get it on. Also, the wider portion of the hole in the prop hub barely goes over the center ridge prop-saver (but I guess it's supposed to be that way as it it's more in front of the prop saver than around it). I'm not sure if there is some trick to get the prop sitting correctly on the front of the prop-saver but I have a feeling that it wasn't balanced well enough. Is there some trick to getting the prop sitting balanced on the prop saver?

-l2t


(I tried asking about this topic over in the power section and got zero responses so I'm trying in the scratch-built section figuring this is where the helpful and friendly technos hang out).
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Old Aug 22, 2010, 08:54 AM
treefinder
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Joined Oct 2004
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Would be best to show a picture of what you have. There are at least two fairly different types of prop savers I'm aware of: 1)the ones for GWS props that have the "nose" as a tapered cone, with the base of the cone about the same dia as most GWS prop center holes, 2) those with two different diameter straight wall portions where one screws it to the shaft after selecting the end that is a close fit to the center hole of the intended prop (I think that the small end fits gws props below about 5" and the larger fits GWS or other props larger than that, or doesn't fit GWS - I forget).

I have found that in some cases, i'll get a prop that fits over the cone type, but doesn't fit snug to the flange at cone base, and the prop will wobble too much for smooth function. In that case I ream out the hole a bit. I discovered that t #2 Phillips screw driver has about the same taper as the cone. So, I used my dremel to sharpen the "fins" of a Phillips insert to act like a countersink and use a drill to slowly, carefully open up a taper. Works best if I just add a bit, and the about 1/8" of motor shaft I leave showing beyond the propsaver just fits in the un opened up portion of prop center hole. That keeps prop centered on shaft, and the clearance allows prop to sit square on the saver. Guess I should show a pic too!

One more comment, be very careful about drilling out the center hole, it's a bugger to keep the new hole centered on the old, and if you get it off, balancing will be way more difficult. Haven't used any, but I see the prop reamers available, that may help keep things centered.
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Old Aug 22, 2010, 09:39 AM
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I took a pic of all the parts but unfortunately the one USB cable that fits the camera crapped out on my and I can upload it.

The prop-saver is anodized blue aluminum. It has square edges not a cone or taper. The front is two concentric cylinders both with flat fronts. The inner one protruding about 1mm.

It came with and additional piece that may be placed on the front for a wider hub hole.
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Old Aug 22, 2010, 10:33 AM
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Learn2turn does you adapter look like this ? http://www.hobbycity.com/hobbycity/s...idProduct=3738
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Old Aug 22, 2010, 07:14 PM
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Quote:
Originally Posted by Wilfor View Post
Learn2turn does you adapter look like this ? http://www.hobbycity.com/hobbycity/s...idProduct=3738
Yeah, it's blue but pretty much the same as that one. Probably the exact same one as the vendor resells HK stuff.

-K
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Old Aug 22, 2010, 07:58 PM
SG Talon... Super Genius.
Lenox, Michigan
Joined Nov 2005
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Hey Learn!

I am a good friend of Springer up there and I am of a different opinion that pretty much everyone i know on prop savers.

My experience with them is that they suck a little performance from the prop over a rigidly mounted prop.

When it comes to the adapters i usually use a non-GWS prop. Either an APC or one of the HK props that have a bigger hole in the middle.

I usually don't bother with balancing.
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Old Aug 22, 2010, 09:39 PM
treefinder
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Yeah, but SGT is a great flyer, and doesn't break props like some of us tend to......

Looking at the HK picture, it is the second version I mentioned, and You either have to use a prop that fits one of the three cylinders, or ream it to fit. What particular props are you using?
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Old Aug 23, 2010, 07:39 AM
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The props are black but look like those GWS-style slow flyer props; likely and HK knock-off.
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Old Aug 23, 2010, 08:26 AM
treefinder
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They don't happen to say Haoye on them in script, to they? If so, they have been nice props for me, lots of thrust, but even though they come with several adapter rings that fit into the hubs, have been not quite fitting most propsavers, I eventually made an aluminum washer with ID to fit my savers.
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Old Aug 23, 2010, 10:03 AM
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Examine your props closely at the hub.

The prop must not have any extra plastic at the hub and must sit flat against the adapter. LOOK CLOSELY for a nice flat fit. Spin up the prop and look at it sideway's from you. Make sure the blades are tracking in the same path IE traveling thru the same plane. Some times a bent motor shaft or bell will cause problems here too. (Crash lately?)

Next make sure the hole in the prop isn't too big allowing the prop to slide back and forth across the face. This will throw off the balance. I usually drill out the rear 1/3 or so of a prop to make the adapter fit nicely. No need to rebalance then.
At this point I have layed some props on some wax paper, filled them with epoxy or hot glue, redrilled with 3 increasing bits from the front thru the back until the proper size is met. Then use the proper size bit on the back to taper for my prop saver.

If you use the hot glue you can slip your saver over a motor shaft with plenty of shaft extending out. Slip the hot glue filled prop onto the shaft with a preheated (lighter)propsaver to melt itself into the prop. (This method works great but wear leather gloves).

And lastly make sure your using alot of bands to hold it on. Find some good surgical tubing, synthetic rubber bands, or lastly some new rubber bands that hold very tightly.
Some larger or fast spinning props will need alot to hold them on. There's alot of forces trying to rip the prop away while your flying.


Good luck
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Old Aug 23, 2010, 06:44 PM
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Quote:
Originally Posted by learn2turn View Post
Question 1: The prop adapter I have. Looks like the OD of the threaded shaft is 3/16". If I want to use it should I drill out my props hub to 3/16" and then re-balance the props?

Question 2: I balanced the props I have then put one on the prop saver and did a test run. Ran okay but got a fair amount of vibration, especially at about 1/3 throttle. Why doesn't the prop balance on the prop saver?

Background--

I just about have my QuickStick kit almost ready.

I have some EP-1047 props for the 950kv motor and balanced them by spinning on a metal shaft slightly smaller than small hole in hub. Then adding tape as needed.

I have both a prop-saver and prop-adapter.

Haven't tried the prop-adapter, need to drill prop hub if I'm going to use it.

I balanced the props and put one on the prop saver. It was very tight pulling the band to get it on. Also, the wider portion of the hole in the prop hub barely goes over the center ridge prop-saver (but I guess it's supposed to be that way as it it's more in front of the prop saver than around it). I'm not sure if there is some trick to get the prop sitting correctly on the front of the prop-saver but I have a feeling that it wasn't balanced well enough. Is there some trick to getting the prop sitting balanced on the prop saver?

-l2t


(I tried asking about this topic over in the power section and got zero responses so I'm trying in the scratch-built section figuring this is where the helpful and friendly technos hang out).
You should not have to modify the prop if you have the correct prop saver. You also should not have to balance the prop. It is a good thing if the prop is a tight fit on the prop saver. Also you may have to run more than one o-ring to properly hold the prop in place.
Mike
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Old Aug 24, 2010, 05:15 PM
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New Jersey, USA
Joined May 2006
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You want to think you should not have to balance a prop, but it may be required. I put this new prop on the motor straight out of the plastic bag and turned the motor over slowly. Of course, there was vibration. Thought it could be a bent shaft, cocked prop-saver, or an unbalanced blade. Struggled successfully to remove the o-ring holding the prop and checked it for balance. It took a lot of tape to bring the prop into balance. The motor is now vibration free. Do not know why I did not check the balance of this one beforehand.
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Old Sep 15, 2014, 10:02 AM
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Do you have to use a prop adaptor or can you just mount your prop on the shaft and secure with a nut
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Old Sep 15, 2014, 11:10 AM
treefinder
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SE MI
Joined Oct 2004
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If you have one of the towerpro motors with threaded shaft or similar, then the prop can be bolted on directly, but it will be a fair distance from the motor can/hub, and a crash can bend the shaft. I like to mount my props (by what ever means) as close to the hub as I can, gives a more solid and shaft saving mounting.
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