Large Model Association Forum

hello iv got a HK diablo that i need a 90mm edf fan unit for but i dont know much about edf's .

link to model

https://hobbyking.com/en_us/hobbykingtm ... m-arf.html


the model's wight is around 2.1 kg without battery's or fan unit .

i all ready have a 120a esc and am wanting to use it if possible.

i have been looking a this fan unit
http://www.turbines-rc.com/en/edf-ducte ... motor.html

but like i say above i am new to edf electric models . i am not new to flying tho .

if anyone could please help me it would be great thanks .

Hi Luke,
Gliders at Newark sell a nice 90mm edf with 14 blades including motor for £99 needs a 120 esc and 6s makes a good turbine sound. A clubmate has two of them.

ok would that fan have enough thrust and what size battery should i use . also would the fan unit i have been looking at do the job and if so what size battery should i use with it . thanks

It gives 3.2kg thrust at just over 90amps would need a 6s 5000mah lipo

Barrie

What c rating should I get and thank you for the info also what kind of flight time should I get with that set up also just out of intrest would the fan that I was looking at geting do the job as I realy like the look of it . Also for intrest what batterys would it take .
Thanks again

The fan you looked at would do the job and cost over twice as much and need 8 or 10s lipo!
Is the esc you have HV or not, what voltage will it handle?
With edf you need the highest c rating you can get as the currents are high.
You would get around 4 mins flight time.

hello everyone thanks for the help I have gone with the jetfan as I want to run it on 10s that way I should be able to take off with some authority as its thrust is 4.7kg but what batterys would you all recommend for a 10s set up I.E what mah and what C rating should I use thanks for all the help

also my esc is a 120 hv

Using the 90 amps 5000mah example above --

5000mah is 5 amps for one hour or 1 amp for 5 hours, amps X mins = 5 X 60 = 300 amp mins

300 / 90 = 3.33 mins run time at 90 amps, with some reduced throttle time gives something like 4 mins

C rating required is 90 / 5(000) = 18 absolute minimum, 30 would put less strain on the batterys

thanks so I will want 2x 5s 5000 mah with a c rating of around 30 c continuous .

would this battery be ok

https://hobbyking.com/en_us/turnigy-nan ... -pack.html

thanks again to everyone

For that battery on your fan you are looking at 4.5 x 60 = 270 amp mins

270 / 98 amps = 2.75 mins

C = 98 / 4.5 = 21.7 s0 the C rating of that battery is fine

A pair of 4500 battery's in series is still 4500, not 9000

Last battery I will ask about but will this one work in a 10s set up ??? Thanks again every one for all the help that every one has given .

https://hobbyking.com/en_us/zippy-compa ... -pack.html

5800mah = 3 1/2 mins at 98 amps, minimum C required 17

thanks every one for the help it relay has helped . if i need any more help i know where to come . thanks

Hello everyone now Christmas morning has been I received 2 turnigy 4400 5s lipo packs with a c rating of 65c continues and burst of 130c and was wanting to know what kind of flight time I should get out of them with a current draw of 98amps also what would you guys suggest for attaching carbon fibre to carbon fibre ?? I was thinking of just using some 15 min epoxy . Thanks everyone and merry Christmas and a happy new year

4.4 X 60 = 264 amp mins

264 / 98 = 2.7 mins about 2 mins 40 secs

As an obvious expert on battery's and all things for electric flight, looking at your calculations I must say as a mere pleb!! I am not really understanding where are coming from. Would you be able to explain How and Why and Where and How you actually arrive at your results in plain uncluttered language! For all the people like me who haven't a clue on how to do it !!
It seems like a minefield !!

In Steves equation the 4.4 is the milliamp hour of the lipo i.e. 4400 changed to amp hours then times 60 to get to minutes.
He then divides the amp minutes by the amps to give minutes! Simples!

Barrie

So a 4400 lipo fully charged gives 2mins flying?
So to get a 10 min flight you need 5 x 4400 lipo packs fully charged???
So charge the batterys for x amount of hours just for a 10 min flight???
That seems an awful lot of batteries ???

98 amps is the killer, that is the same current as 8 electric fires, and more than enough to weld with !

The time calculated is for continuous full power rather than real world throttling back, the 5800 lipo further up is of course more suitable

Hello again people how would I go about attaching carbon fiber mounting tabs to my carbon fiber fan and also how can I measure that they are bother level on the fan unit . I don't know if it well help but it's a jet fan 90mm 700.68.1400 thanks people again