EDF 3 Blades or 4 Blades?

[edmond22]

edmond22,

i say already i never remove blade!! i have one het and one more stock 3 blade, it seams you have even worst listening power. gee. worst then me still can comment others.

Read your own post
"But looking on other threads in the forum, the one under 6 blades to 3 blades convertion, isnt the 3 blades setup supposed to bring my plane to a higher speed?"


NOW TELL me, did you ask or did you not?

[joe yap]

Oh! I almost forgot.

For start, please do yourself a favour and measure the current draw while you perform the experiments. As long as the current and voltage draw is within the safe operation parameters of the motor, battery and ESC, you know that they'll be saved. You can't even compare properly if you do not measure the current, and thus calculating the input power.

Anyway, experimenting in static conditions can be quite different than in the air. Your static thrust will drop to zero soon after the aircraft takes off. While your model is moving, the currenlt draw will also decrease. In your previous experiement, I can only conclude that the 4 bladed setup is drawing more power from your system. The static thrust and efflux velocity should not be concluded so soon, unless you decided not to do anything on the exhaust ducting. Remember, for ducted fan units, work is only produces after the air leaves the exhaust nozzle, not just after the fan.

[joe yap]

Sorry, forgot its not helicopter thread.

HDB,
You really know how to break ice.......

[mirage2k]

edmond i say one more time.

my post is refering to compared to my 4 blade

please read once more on the paragraph

have you got litening power failure? i am worried for you

[mirage2k]

thanks joe, although a little difficult to understand, but i will try to digest what you said

CHEERS

[edmond22]

edmond i say one more time.

my post is refering to compared to my 4 blade

please read once more on the paragraph

have you got litening power failure? i am worried for you

I am talking to Bill Clinton now. "No I do not have a sexual relationship with that woman!"

Whatever Bill. Was nice talking to you.

[joe yap]

Mirage2K,

Just trying to cool you down. Honestly, I know Edmund personally, and I know he mean well. Just that his way of conveying the message is like our seniors talking to us at our workplace. If you cannot that the tone, just focus and pick up those useful messages he mentioned and use it for yourself. Just read between the lines and swallow a little pride if necessary.

Edmund,

You need to set the correct frequencies for the user to receive. You using 2.4 right?

[mirage2k]

the cabbage is in the bag, sometimes it is not running. OH YA ! guitar falls down

[mirage2k]

joe , i am so sorry to tell you that i am not working for him, he is not my senior or what so ever . i dont have to be under his nose as what he wants actually. tell him to stop talking to people with his nose up or rather... he is being like the king so others must listen, cannot a little changes, eg: people like to use 3s cannot - MUST 4s ,MUST HET ,MUST WIMOTEC. F%^& him la.!!

singapore is small, the world is small. we will meet.

[mirage2k]

one day

[mirage2k]

joe did you know he didnt help me very from the begining? he is just here to have a fight with babylon, then fight else where la.

[joe yap]

Basically, he sounds like saying, "If you do not know how to build your own car from spares, just buy one which is guaranteed roadworthy", if you take it positively without getting your emotion on your way. May be hard to swallow, but do stay focus.

Your call. Good night folks.

[mirage2k]

i am trying to understand eg how a car wheel work, y it is round , y broad and y narrow wheels. thats all. if he is suggesting that must het must wimotec. then it is simply the wheel is broad = no reason. HET have 4 blade means 4 blades nothing to talk. 3 blade cannot means cannot. ?????????????????????????????????????????????????? ?????????????????????????????????????????????????? ?????

anyway i am not here to make a big hoo har with the yuppe. sometimes being nice is difficult. come on la, y make yourself so miserable.

[mirage2k]

joe , i am so sorry to tell you that i am not working for him, he is not my senior or what so ever . i dont have to be under his nose as what he wants actually. tell him to stop talking to people with his nose up or rather... he is being like the king so others must listen, cannot a little changes, eg: people like to use 3s cannot - MUST 4s ,MUST HET ,MUST WIMOTEC. F%^& him la.!!

singapore is small, the world is small. we will meet.

rephase
---------------

what i meant is that we are all hobby people, we come here all to share. i really appreciate his help on his technical data, maybe complications to what i really meant on my begining post. i may have put it in a manner that edmond22 have thought that it was the 6 blade and 3 blade conversion. instead of 3 & 4 blade comparision of course & his concepts on the 'should use fan & motor' . as we know flyers are not much in singapore, if we meet one day by chance, i may think we will sure be 'paiseh' one, why we have to become like this? didnt meant to be personal, edmond22, really no hard feelings. maybe next time dont phase it too hard on my post? i do admit i have mistaken earlier you are refering to babylon instead of me, but your whole paragraph not only applies to babylon, it applies to newbies edf flyers as well

cheers to all
especially edmond22

[edmond22]

rephase
---------------

what i meant is that we are all hobby people, we come here all to share. i really appreciate his help on his technical data, maybe complications to what i really meant on my begining post. i may have put it in a manner that edmond22 have thought that it was the 6 blade and 3 blade conversion. instead of 3 & 4 blade comparision of course & his concepts on the 'should use fan & motor' . as we know flyers are not much in singapore, if we meet one day by chance, i may think we will sure be 'paiseh' one, why we have to become like this? didnt meant to be personal, edmond22, really no hard feelings. maybe next time dont phase it too hard on my post? i do admit i have mistaken earlier you are refering to babylon instead of me, but your whole paragraph not only applies to babylon, it applies to newbies edf flyers as well

cheers to all
especially edmond22

Hey Bro,

Dun worry about such debates, they are normal and it is healthy and good. It is perfectly fine to stand your ground, when we meet in the field, I sure to say hello with a smile to you wan. The more the discussion or debates, the better the advancement of this hobby.

I apologise too for getting carried away, will take your words into serious considerations. Anyhow, I am known to be this straight lar.

Like you say we will meet, but not too worry, it will surely be an alright flying day for all of us.


Just to get you up to speed.

Are you able to measure your amp draw between the 2 sets of blades? Get the full draw amp, times it by the voltage you are feeding in and that gives you the watts. Measure the weight of the ready to fly weight, divide the watt you measured by the weight to arrive at watt per pound.

See http://www.rcuniverse.com/magazine/a...rticle_id=1077
A good article "EDF Power & Efficiency - Thrust vs. Watts"

150w/lb for Fair EDF performance
200w/lb for Good EDF performance
250w/lb for Great EDF performance
300w/lb (or greater) for Extreme EDF performance

This above will give you a good indication of what to expect. Also, do take note of Joe Yap's mention of efflux velocity, the air speed exiting behind the nozzle will influence how fast you are going to go. So if I were you, I will pick the higher watt per pound rating between the 2 that is still acceptable within esc and battery ratings. Then the next thing to do is how much I want to squeeze the exit cone behind, you can experiment from there after flying it to get a feel first. Again, looking and remembering the impression you get from flying is very very subjective (as to experience), will be good to use a software of some kind to get some readings like speed. With that you can make adjustments and "tagged" it down to measurements. The feel by hand method of thrust is really (honest!) no use, those fast ones will be stalled at static airspeed and you won't feel a lot of thrust going on (like my F20 for example, hence the need for bungee launch).

Here is a download link to Wavescope, go http://www.sprut.de/electronic/soft/scope.htm

To measure speed, simply take a video or sound recording (sound is what counts) and feed the flyby sound sample through the program and you will be able to get a pretty good accurate reading. See example attachment of a screenshot for a Ritewing TL50.

Also, if you are interested, see http://www.daddyhobby.com/forum/showthread.php?t=29990

I just can't stand multiple nicks troll post, my apologies, just can't stand it. That was in 2007. If you read it, take note of the people who replied and what was being said, the same old theory with replies that clearly debunked the whole thing. You can't keep spinning the same old shite that doesn't work and derail people who really want to learn, Chinese saying "walk unnecessary steps". I have nothing against Viper too, but for some strange reasons, compare this thread and that thread I gave, do you see a uncanny similarity on Babylon's post, then Viper supports? Both never went back to that thread to ever justify, support or back up that theory. So he gave you an answer, is it really properly supported? From the look of it, I still prefer my method of measuring, take data, then recommend than even giving you an answer straight on which will be faster.