Hi Eddie
First thing i did was to true the hub on the HET motor with a dial indicator. Then i Balanced the fan Dynamically using a Chadwick Helmuth Vibrex 2000. This is an expensive balancer i use for balancing full size helicopter rotor and tail rotor blades. At first i thought it wouldnt be sensitive enough, but at 10,000 rpm it shows up quite nicely,and after 6 runs, it was very smooth.It would want to be ,cause it cost $6ooo, 10 years ago.
A good alternative balancer, for $240, is the bobs workshop balancer,although i am still getting the hang of it.(Not as easy to use as the Vibrex, for obvious reasons! $$$$$$$$).
The key is to get the hub right, thats 90% of the battle.
Steve

Originally Posted by heliclown

... The key is to get the hub right, thats 90% of the battle.
Steve

+1 ....

OK thanks to all of you who have mentioned tips and tricks of what you guys are looking for with this fan to run smooth. Heliclown, that's the first bit of definitive information I've gotten on how to actually balance this hub / rotor aside from turning the whole unit on the shaft a few times to minimize course shake. Though many folks mention that they balance them. Thank you for that. I don't have those sorts of balancers but at least I know what I'm up against! Tamjets / Tam says he is working on a new fan adapter using these blades and I'm very interested in what he comes up with. It won't be the $30 fan anymore but at least it will be able to be run at 4kw or so plug and play.

In the meanwhile I have 2 of these and I'm looking to use one in a 1800 watt 6s setup and another in a 2700 watt 8s setup. Hopefully I can use some white trash balancing techniques to get them to run good enough for the long term at those levels. Oh yeah, we have one vote for using thin CA to bond the blades together and another vote for a "top secret" blade bonding technique to help keep the unit balanced? Any more on that?

Originally Posted by Eddie P

OK thanks to all of you who have mentioned tips and tricks of what you guys are looking for with this fan to run smooth. Heliclown, that's the first bit of definitive information I've gotten on how to actually balance this hub / rotor aside from turning the whole unit on the shaft a few times to minimize course shake. Though many folks mention that they balance them. Thank you for that. I don't have those sorts of balancers but at least I know what I'm up against! Tamjets / Tam says he is working on a new fan adapter using these blades and I'm very interested in what he comes up with. It won't be the $30 fan anymore but at least it will be able to be run at 4kw or so plug and play.

In the meanwhile I have 2 of these and I'm looking to use one in a 1800 watt 6s setup and another in a 2700 watt 8s setup. Hopefully I can use some white trash balancing techniques to get them to run good enough for the long term at those levels. Oh yeah, we have one vote for using thin CA to bond the blades together and another vote for a "top secret" blade bonding technique to help keep the unit balanced? Any more on that?

I Used epoxy to bond the front and rear locking rings on to the blade roots, then balanced it. Note epoxy doesn'"t really stick that well to the plastic, should take up any play between the blades and rings. Thats my theory anyway. I will keep you posted on longevity, if you like.
Steve

Yes please!

Also, what did you do to balance the rotor once it was glued together? Add material or take material away?

Originally Posted by Eddie P

Yes please!

Also, what did you do to balance the rotor once it was glued together? Add material or take material away?

In the CS 90mm 12blade instance , i personally never remove material, I add epoxy and core solder for extra weight if needed, remove the spinner and add it to the front of the front locating ring. I remove some of this (if necessary) with a dremel.Hope this helps.
Steve

Yeah that does help. I normally add strips of extra stocky tape to the inside of the rotor base wall for traditional fans. But of course the CS90 is different so there is not an easy place to add much of anything. And since the hub is so far forward I was wondering of that would add some gyroscopic instability and the fact that it is part of the structure - I suppose if the blades are bonded it's not as big a deal to take the spinner on and off to add small weight for balance. Thanks again for the advice on this fan.

Flew my FF F-100 on 7S with the CS 9012 fan, Turnigy XK4074-B-1400 motor and Red Brick 125A ESC with 5A bec. The improved performance over 6S was well worth the cost of the 1S pack (to augment our 6S packs). The draw was 94a and almost 2200watts. Didn't have time to measure the thrust but the aircraft performed as though it had lost a pound of weight! My Zippy 30C packs took approximately 4100-4400mah charge after my 5 minute flights.
I will post the measured thrust in the aircraft when I get a chance.
Cheers

Thanks 4Stripes!!
I have been working out for running it 7S or 8S, and the pain of batteries to use etc.
I have a Red Brick 125A lying around too, though also the SS 190A/200A.
And the XK4074-1400 for the F-100.

In weight terms, I was going to do 2 x 4S 5000mAH 30C Zippy's for 1052g total weight. Or maybe 25C's (a bit thin on Amps) for 938g.
With a benefit of using those in my F-16 too (maybe, but it is using the XK3674-1400).
Plus the 4S can be used for a couple of other Prop planes too.

7S.... A 4S & 3S mix is wasteful to me.
I guess I have a chance to use 6S 5800 30C Zippy's (I have), with a 1S as you mentioned. But then the 1S is somewhat 'wasted' too - not totally, but limited to 2 aircraft's use.
But I also like 7S for it being a bit less power/stress on things compared to 8S. And it could very well still be a great power system that is adequate, or above, for the F-100 (and F-16).

I'll have to ponder over, and do the numbers, on the "1S addition" possibility......

Hi Peter
The 1S packs are cheap. The only drawback was the 4mm bullet connectors built into them for the battery leads. I doubted their ability to handle +90Amps so I cut a corner of the plastic away to get my soldering iron good contact and soldered them to the battery leads. After soldering the leads in I epoxied the plastic corners back in place.
I'm pretty sure 8S will push the amp draw over 100 so 7S will be my final setup on the XK4074-B-1400. Most of my planes fly fine with 6S but a couple needed the extra "push" so this was an easy and cost effective solution.
Cheers

I meant to ask....
What exact batteries did you use? The 6S and 1S, brand, capacity.... where from, cost etc.
Sounds like 5000mAH.

I'm using the HK Zippy 30C 6S 5800mah and the 1S 30C 6200mah hard case.
Cheers

https://www.hobbyking.com/hobbyking/s...idproduct=9935

https://www.hobbyking.com/hobbyking/s...r_Lipoly_.html

Thanks. That looks a fair possibility.
Could it be taken out of the hard case totally? But at least your idea improved it anyway.

The case is glued together and doesn't add much extra weight. Space isn't an issue in my F100 or Mig15. You would have to saw it apart risking damage to the lipo sac.
Cheers

Hey fellow HUN drivers, flew my HUN at the Austin Jet Rally, it was WINDY. But to see how I handled the cross wind and gusty conditions you can see my landing here:

Central Texas Jet Rally Austin 2012 (Long Version) (21 min 25 sec)

Go to 08:51 in the video. Not very fun flying, but it was a good time anyway.

Also, a columnist from Flying Models was there and my plane will be in that coverage, so yay for the Fly Fly HUN!