Took the plunge into the EDF era - lots of question to all the EDF Jubkeis

[Bobmic]

So the weather is not cooperating and its about time I learn how to hand launch.. so I ended up with an RC Lander F9F 70mm EDF.
With Jeffs help I actually flew it once just to put a check mark that I did it... The weather was not good, CG not good etc. but it is in one piece and now I am looking to understand what I need to do and how.
My plane came with 70mm 4s setup (Sapac - don't have the numbers from it but I measured around 800W) and a 68mm 3s alloy (Lander KV-4370) setup new package which was not used.
Even though it was a bit windy when I maidened the plane I can not say it had too much power and it will be nice to a bit more oomph.

So here we go:
1. I saw the 10 blade alloy DPS units at hobbyking (one for 4S 3000Kv, 1200W and the other 6s 2200Kv, 1900W)
First question is the fan blade count - what is really the effect of the number of blades in the fan - I see 10 blade units, 5, 7 etc.
I was looking at the two units bellow, both have the same thrust but 5 bladed unit is lighter and has lower max current..
2. How do I balance the fan? I know how to balance a regular propeller but not an EDF fan.
3. Since I would prefer to keep my setup within the 4 or 5s can I mix and match fan units and motors? If I can, how can I find the best match, what to look for and which one will be the best option?
4. Finally I saw many online retailers but I you prefer to hear from your experience - which ones should I consider.
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=28498
http://www.hobbyking.com/hobbyking/store/__17220__Alloy_DPS_Series_68mm_EDF_unit_with_3580kv_Motor_1000watt.html

Thank you,
Bobby

[flying saucer]

Congrats on the maiden, and welcome to the Panther club!

If you're looking for more power, I don't think you'll be happy with either of those choices. Your best bet is to wait for the 6S 10 blade unit.

[sihinch]

You could try this....

http://rc-castle.com/shop/product_info.php?products_id=2864

70mm 10 blade fan, with motor for 6S, $84.

[Wingnutz]

Bobmic,
I'm a jobkeis (junkie?) but not an expert, so I'll offer this for the experts to pick apart.
1. Fan blade count...increasing blade count almost seems like increasing pitch on a prop...keep the diameter the same, you're gonna use more power to drive more blades...sometimes requiring a higher S count battery and perhaps a KV change in the motor.The ratio at which extra watts translate to extra thrust is more of a moot point. The new generation of "Whooshy" fans use higher blade count to produce a quieter "whoosh" sound rather than the whine produced by earlier lower blade count fans.
2. Balancing the fan..I've googled this topic several times and I'm still not sure I understand it...everybody says balance, few say how. What I've tried (pick this apart you experts, I'd like to learn!) is to mount the fan on a GP prop balancer, establish the heavy side and then mount tiny scraps of electrical tape inside the fan hub on the light side...so far seems to work. I think that's called static balancing and the knowledgeable EDF types balance dynamically also...still in the black magic category for me. My present EDF project uses a 27mm fan and I'm not even gonna try to balance that one!
3. Mixing and matching fans and motors can be done but you need to make sure motor, fan, ESC and battery are a good match for each other and your model...I'll leave a full answer to that one to the experts.
4. Good bet retailer? I'm not a good one to answer...I finally ordered one of the HK alloy 90mm 12 EDF units from HK, but it's my third fan, second motor and the model it's going in isn't even started! In the smaller sizes, I've had good results from GP Hyperflow units.
5. Whatever else, ...have fun!
BIll

So the weather is not cooperating and its about time I learn how to hand launch.. so I ended up with an RC Lander F9F 70mm EDF.
With Jeffs help I actually flew it once just to put a check mark that I did it... The weather was not good, CG not good etc. but it is in one piece and now I am looking to understand what I need to do and how.
My plane came with 70mm 4s setup (Sapac - don't have the numbers from it but I measured around 800W) and a 68mm 3s alloy (Lander KV-4370) setup new package which was not used.
Even though it was a bit windy when I maidened the plane I can not say it had too much power and it will be nice to a bit more oomph.

So here we go:
1. I saw the 10 blade alloy DPS units at hobbyking (one for 4S 3000Kv, 1200W and the other 6s 2200Kv, 1900W)
First question is the fan blade count - what is really the effect of the number of blades in the fan - I see 10 blade units, 5, 7 etc.
I was looking at the two units bellow, both have the same thrust but 5 bladed unit is lighter and has lower max current..
2. How do I balance the fan? I know how to balance a regular propeller but not an EDF fan.
3. Since I would prefer to keep my setup within the 4 or 5s can I mix and match fan units and motors? If I can, how can I find the best match, what to look for and which one will be the best option?
4. Finally I saw many online retailers but I you prefer to hear from your experience - which ones should I consider.
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=28498
http://www.hobbyking.com/hobbyking/store/__17220__Alloy_DPS_Series_68mm_EDF_unit_with_3580kv_Motor_1000watt.html

Thank you,
Bobby

[Bobmic]

Thank you guys.
I actually looked at the Cyclone option but the HK 6s was back in stock and cheaper (I contacted RC Lander and they said this is the same unit).
The fan I got in my plane is a 70mm Sapac with 3200kv 4s motor, from what I could measure it produced 800W max and 1.1kg thrus with a fresh battery (plane weight with battery is 1250gr).
With this setup it flew ok but nothing exiting beside the horrible high pitch EDF sound.
I did not research too much the balancing portion and I get the static part even though with multiple blades I am not sure how easy it is. The problem is dynamic balancing due to the high speed of the fan, this is not really an option with our tools as it requires an accelerometer and accurately repeatable rpm control which ends up to be too much effort these types of EDFs
- The main question is relation between motor power and thrust...