Gem Fan Nylon/Carbon Props: Are the hubs really THIS off balance!?

H

halfpress

Member
I bought a dozen of the $2.00 Gem Fan Nylon/Carbon-Reinforced 10" (1045/1045R) props last week to use with my F550. Everyone has been scaring the crap out of me about the stock 10" DJI props (though I'm hoping the ones I have are the newer type) and opinions seemed decent about these for the price.


I started balancing them last night and was horrified at the ginormous gob of hot glue needed to make the hubs seem anywhere near balanced. I found at least one YouTube example online of someone else in precisely the same situation.


Is this really the case or am I just being a total idiot about the balancing process? The DJI props needed some sanding and glue, but nowhere near the mountain of glue the Gem Fans have needed.


Above all, is this just the reality and, once gobbed up, they still work well? Or should I avoid the props if they need that much attention?


Any input is appreciated! :)
- Aaron
 

T

tstrike

pendejo grande
I think they make the hubs out of balance to counter the jello from the dji arms, it's really an elegant system.
What balancer are you using? I've only balanced the blades, the couple times I tried to balance the hub on a graupner things went terribly wrong.
I wouldn't get real anal about your props at this point.
 

H

halfpress

Member
I'm using a DuBro balancer and have had quite good luck with it. I'm balancing the props mostly to reduce vibration as much as possible since aerial photography is what I do most with the F550.

I might go ahead and see what I can do with a set of the Gem Fans - even if the balancing process ifsobnoxious. I want to compare them to the DJI stock props since the Gems are less flexible. I might grab Graupners later on, but hate having to deal with adapting them to the keyed DJI motors. Gem Fan has a set of carbon fiber props that are DJI-ready (I think) that seem to compare favorably to the Graupners and are a bit cheaper.
 

T

tstrike

pendejo grande
10" graupners go right on the dji motors, you may have to add a washer. I've had good luck with my Dubro and gemfans, but like I said, I only balance the blades on'm.
 

H

halfpress

Member
That's good to know! I might go with the Gem Fan all carbon fiber ones if I can find some assurance that they don't suck. :)

- Aaron
 

D

Dewster

Member
halfpress said:
That's good to know! I might go with the Gem Fan all carbon fiber ones if I can find some assurance that they don't suck. :)

- Aaron
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I had a pair of Gemfan full carbon fiber props. My craft flew less than five minutes before a blade separated from the hub. Carbon fiber is brittle. You'll get a stiffer ride too. I think having blades that flex a little is better unless you have some highly tuned ship. I use Graupners. They may be expensive, but so were those carbon fiber blades that ruined my ship. You have a lot to lose if your blades disintegrate in flight. Spend the money.

Think of the reasoning behind Gemfans carbon reinforced nylon props. It should be called nylon reinforced carbon props.
 

SMP

SMP

Member
Using a Dubro... Everything is out of balance out of the bags. Gemfans, Graupners, APCs, Xoar Woods... Best of the bunch so far has been the Xoar Carbons but even then usually only catch 2 out of 8 with no hub balance needed. We've come to accept that balancing both blades and hubs is just part of the process and lowered our expectations...
 


Olemil

Olemil

Member
To the OP, I too just received 8 of the nylon/cf filled Gemfans and the hubs really stunk on balance. The blades seemed to balance pretty easily, but when it came to the hubs, I tried 3 different props and after globbing a boat load of CA on the hubs (still weren't balanced) I threw them back in the bag. I too use the DuBro balancer which works well. I have the stock 1038 DJI 10" props on now but would like to maybe try some Graupners if I can figure out which ones to get for a stock F450 running 3S. Good luck with your props.
 

Olemil

Olemil

Member
Fiveflat said:
How do you know when to balance the hub as opposed to the blade?
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After you get the props balanced so they lay perfectly (or close to it) to being horizontal, then stand the blade up vertical and see if it drops back to horizontal. If it does, remember which side of the hub was facing down and rotate it to a different spot and let it drop. The heavy side of the hub will always be facing down towards the base of the balancer. Hope this helps and isn't too confusing.
 


H

halfpress

Member
Is there a reason why Graupner 10" props are virtually impossible to find in stock - at least in the US? Every source I check is old out right now. :(

- Aaron
 

T

tstrike

pendejo grande
Graupner filed bankruptcy, no word on if someone will buy their assets. Rumor SJ Propo may buy them.
 


Olemil

Olemil

Member
So it looks like if I want some Graupners I better jump on it soon. There are some dealers that still have them in stock in the US that I've found. Do I want the 10"x5" for my stock F450 running 3s? I'm not doing any lifting, just plain buzzing around. Do I need any type of adapters or washers for them to fit properly on stock DJI 920kv motors? TIA
 

H

halfpress

Member
Olemil said:
So it looks like if I want some Graupners I better jump on it soon. There are some dealers that still have them in stock in the US that I've found. Do I want the 10"x5" for my stock F450 running 3s? I'm not doing any lifting, just plain buzzing around. Do I need any type of adapters or washers for them to fit properly on stock DJI 920kv motors? TIA
Click to expand...

So far, every online dealer I check is either sold out or, more irritatingly, only has clockwise blades but no CCWs. I have not yet found even two dealers I could use to split an order to make a full set. Really frustrating.

As I understand it, the 10" hole size is right. The 8" ones will need to be reamed out carefully. I think you could use either with the 8" being a bit more nimble. Supposedly 10" is preferable for 3S and vice-versa, but not sure how hard and fast that is as a rule.

And if you want to share (via pm) a dealer with inventory (after you order your own), I'd be forever greatful. ;)

- Aaron
 

SMP

SMP

Member
We use washers on top of Graupners on the DJI motors. This is a must. Dont be fooled. It may feel tight without but its about a half thread worth. Check. you'll be scared you waited this long to washer up.
 




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