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Old Oct 10, 2012, 08:00 AM
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Greece, Attica, Athens
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Originally Posted by AirX View Post
anlucas,

You are clear and concise in your testing. I appreciate your work as you give good feedback on what you are trying to do.
I have been told in the past, you cannot lead if there are no followers...

Cheers,
Eric B.
Oh Eric thanks - just trying to do things that are useful and share them!
I am one of your followers!

Andrew
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Old Oct 10, 2012, 11:56 AM
EDF rules... :)
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Originally Posted by anlucas View Post
Oh Eric thanks - just trying to do things that are useful and share them!
I am one of your followers!

Andrew
Thanks for that, but its guys like Stuart Maxwell and Klaus Schornhorst that have broken the ground in fan design. Stuart with his Stumax designs and Klaus with his Winmodels WM400 which is now the Velocity WM400.

Keep up the great work.

Eric B.
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Old Oct 10, 2012, 02:01 PM
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Spain, GA, Santiago de Compostela
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Quote:
Originally Posted by PeterVRC View Post
I would not use the 2100kv, unless it is a LIGHT plane!
Your maths look fine, so 2.5mins at WOT...... maybe 3.0mins with care.
Quote:
Originally Posted by AirX View Post
The 2855-2300 and the 2800-2100 tests were misquoted in the early posts and Anlucas has written a post showing the correct numbers.

Here is another post that shows a test of the 2100 is as posted here:
http://www.rcgroups.com/forums/showp...5&postcount=10

My 2300s run pretty much as tested by Anlucas.
Quote:
Originally Posted by Extreme_RC View Post
With 43-45A you would be wanting to fly with one pack to keep the weight down. The nanotech 2200 lists at 253 grams, thats way over the weight of a true 2200 pack, have you done a 1c cycle test on your charger to see what the actual capacity is? I know guys who have put 2500 back into packs labelled as 2250! I would be inclined to go with the 2300Kv setup and use your packs as singles to start with, see how it flies, if needed get some bigger packs. Running two of yours together is going to make it pretty heavy for the power level.
Thanks Peter, Eric and Ectreme RC.
Given your suggestions I think I'll go for the 2300kV motor (maybe I'll also get the 2800 just in case I wanna upgrade later on...)

I'll check to see the actual capacity of my packs... maybe I can get some bonus seconds, hehehe.

Also, thanks to Anlucas for the test figures!

Now for more questions. Given the several possible motor kVs and cell count, does the top rpm the fan can achieve change significamtly the characteristics of the sound? Or is it just basically the same? I mean do I get a higher proportion of white noise from higher rpm setups?

Also, I came to understand the frame is also critical for the sound, and I'm trying to choose one for the 4S 2300kV setup. Any suggestions? I've been impressed by the sound on videos of a T-45 hawk (with extra cheat holes I think) and the Durafly Vampire with this fan. I don't mind adding yet another EDF to the fleet, hehe. But instead I could upgrade an FMS Dassault Alpha I already own with the CS10, but it has a double "outlet" and I don't have a clue if it will sound anything as good as these other two airframes. Anyway If it rolls and loops OK it's fine with me. Thanks for the read arrows video, ExtremeRC. I have a smaller 64mm t45 that I love to fly. No speed record needed (for now at least)

Thanks all again
Washington
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Old Oct 10, 2012, 04:52 PM
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There is a problem with these 'test figures'.....

14.4Vm
33.32Ap
330Wp
1.1 Kg

They don't tell you much at all.

It is not a lot of use knowing Vm... Volts Minimum. Or Ap... Amps Peak....
Or Wp... Watts peak.....
And even the 1.1Kg is no real use.....

1) Vm could occur at many time points.... it depends on how long you ran the motor. And at what power level - constant? Varied at any point?
Most likely Vm was at the end of the run..... however long that run was. Run it longer and Vm would have been lower. Don't go to WOT later and Vm would have gone lower if you had. THAT battery could give a fairly different Vm than another battery - even one of the same type.
So knowig Vm alone is useless really.

2) Ap will pretty surely occur right at the initial test start up. It will be a lot higher than you see for the rest of the motor run. It will alter according to how good a battery was used.
So knowing Ap alone is useless really.

3) Wp is again highly likely to be the initial start up point in time. And Watts will drop off a lot after that, due to Volts and thus Amps dropping off a fair amount right from that time point onwards.
So knowing Ap alone is useless.

4) 1.1Kg... when?? Maximum? For 3 seconds? Or ongoing (hopefully)?

Oh dear.... now all four are useless numbers..... LOL

For any info to be of real use to someone wanting to know how a motor/fan/battery combo goes it needs a LOT more info.
Those first 3 ARE useful, for certain reasons they can be good to know (not overly good use ever though), but all the other missing ones are far more useful.
1) What battery - ALL its specs
2) Ongoing Amps and Watts.... they actually decline all of the run, but generally somewhat stabilise after 30secs, so if you are going to use 'fixed' numbers to list, wait and list those ones. Best is to list peaks AND ongoings. But ongpoings are the most useful.
3) Thrust... again, annotate peak, but then after stabilsied decline (30secs or whatever you chose)
4) TIMES.... that you recorded those values at

All that those numbers above tell me are:
1) 330W is very low and it is PEAK, so it would drop to 250W most likely.
Fine if you only need that much power/thrust but maybe you do....
Maybe it was a poor battery, so if I use a better one it might run X amount more powerfully.
2) Ap of 33Amps, so will give you a guide as to what ESC rating you will base that choice off.
That is all..... and that is not enough to be of any use to work out what will truly happen when you use it.

And far far better..... VIDEO the entire test, with the camera recording all the meters. Including the throttle point can't hurt either.
That will catch the entire process, as well as the meters 'min/max' readouts.
And then you can look back later and ferret out all of the USEFUL numbers to post.

.....
I am not actually picking on Anlucas... he helps out a LOT with things all over RCgroups!! But it is more useful help (in this case) to list numbers that are actually of use to guide users to the meaningul results of a test.
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Old Oct 10, 2012, 04:57 PM
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For sound... unless someone has done it to know, you won't truly know until you try it.
Basically more airflow 'forced' through, means more white noise and jet/whoosh sound. So a restrictive airframe will sound good even at lower thrust levels, but a streamlined ducting system needs more power/airflow to reach that same sound level.

White noise comes from ANY air molecules 'having a difficult airflow path', LOL. Whether inlet side, through the fan, or exhaust side. So they ALL play a part in the grand total.
eg Any 1000mm jet airframe, with a fan driving it to 100g of thrust (LOL) will pretty well have NO jet/whoosh sound.... very very low. As the airflow through the whole system will be very easily flowing without molecules banging into, crashing, off surfaces etc. Some very low fan amount.... almost zero inlet or exhaust side....
Throw in 2.0Kg thrust into it and it will be HUGE noise creation!!
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Old Oct 10, 2012, 05:52 PM
EDF rules... :)
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Peter,

Your wrong about the post that anlucas posted with the numbers from the 2100, it says a lot.
The Vm is just a 4 cell pack its not dropping under load in fact there seems to be little load on it knowing the load of the rotor for virtually any rpm 0-60000rpm.
The Ap shows the same that the motor is not under much load, then the Wp again shows the load is low mainly because the rpms are low such as the 2100kv with 14.4 volts at an 80-90% efficiency would show. The 1.1Kg is nothing to sniffle at for a 4s setup under load with such a low kv. My calculator says that the 2100kv motor would make ~27000rpm on 14v and 82% motor efficiency.

Dude you need to integrate into society instead of denigrating everyone to feed your ego. There was absolutely no reason to attack anlucas on his numbers.

I have to agree with Mark at Extreme, a lot of your posting is just hot air/noise to give your ego a boost.

Eric B.
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Last edited by AirX; Oct 10, 2012 at 06:04 PM. Reason: Sorry, I should not try to squelch you. We just get tired of all the useless noise.
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Old Oct 10, 2012, 06:19 PM
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I explained why they are USELESS on their OWN.
It is plain and simple why.

The 1.1Kg doesn't tell a thing... it might be 1.3Kg often off peak bursts.... or he might only have listed 1.1Kg as the peak burst. His number doesn't tell you a thing.
If someone NEEDS 1.1Kg, and his are burst.. then that was useless to them! As they will only get 800g ongoing etc.

Vm... no use without knowing the battery. A better battery might drop less. His might have been a 100C battery. So when you use 30C it will flounder more.
Without knowing that number it is useless too.

Those numbers only become PARTIALLY more useful, because they are low and thus tell you in this case the motor/battery were doing it fairly easily.
But in more typical and critical setups they would be severely lacking any useful information.

That is a pretty pathetic support of rubbish you have done there.... for someone who knows more.

Says a "LOT"???? It says LITTLE of use.
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Old Oct 10, 2012, 06:34 PM
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Joined Jul 2011
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I just got my fan in the mail and I put it into my H2 today.

I had really big intentions of slipping a milar tube into it but for the love of God I could not do it. The problem is obvious, the inner diameter of the duct is smaller than the outer diameter of the fan. So when I slip the rolled milar into the duct exit I cannot fit it around the fan to tape it on.

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I pissed around with it for an hour trying to get it to work. It seems that I would have to bore out the exit duct a couple millimeters just to be able to use the thrust tube. I remembered Gary at efflux say in another post to just call him up whenever anyone needs help making TT's. For some reason the call didnt connect proper because when I called the listed number on the site I got some random person who had never heard of Rc's and couldn't understand Canadian too well.
Anywho I went without the tube for now just so I could run up some numbers on my new fan in the jet. Here is what I got:

5s 3300mAh 30C
15.59vm
106.9ap
1787wp
3 mins of near full throttle


4s 3500mAh 35C
13.11vm
82.96ap
1130wp
2.52 min duration
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Old Oct 10, 2012, 06:45 PM
EDF rules... :)
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Quote:
Originally Posted by PeterVRC View Post
I explained why they are USELESS on their OWN.
It is plain and simple why.

The 1.1Kg doesn't tell a thing... it might be 1.3Kg often off peak bursts.... or he might only have listed 1.1Kg as the peak burst. His number doesn't tell you a thing.
If someone NEEDS 1.1Kg, and his are burst.. then that was useless to them! As they will only get 800g ongoing etc.

Vm... no use without knowing the battery. A better battery might drop less. His might have been a 100C battery. So when you use 30C it will flounder more.
Without knowing that number it is useless too.

Those numbers only become PARTIALLY more useful, because they are low and thus tell you in this case the motor/battery were doing it fairly easily.
But in more typical and critical setups they would be severely lacking any useful information.

That is a pretty pathetic support of rubbish you have done there.... for someone who knows more.
I took your criticism as an attack.
There is no real need to denigrate anyone even if thier wrong.
Bud if you were so knowlegable you would not need to take a cheap shot like your last sentence.

Eric B.
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Old Oct 10, 2012, 06:51 PM
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Probably needed a better constructed sentence there (that last one).... sorry.

But I don't see how you could warrant supporting it.... your info was RIGHT... but even with that BIT you outline, the main info is still severely lacking truly useful stuff. Which you would know.
So it is more like you are trying to build a case... a weak one.. to support Anlucas.
I am not 'picking' on him.. it is just a fact that more info is far more useful. And that little list of 4 numbers, and their little content they can pass on, aren't anywhere near enough for great use to anyone wanting to use that system.
If you want to help someone, then HELP them... not give them a little trickle of info, that most people won't even be able to reverse engineer/decipher (like we can), and will be more like giving them 'half a brain to be dangerous"! LOL

And at the very end I did outline it was a request for Anlucas (and anyone) to post the USEFUL stuff, rather than just severely lacking portions of the results.
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Old Oct 10, 2012, 07:15 PM
EDF rules... :)
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Ok, I will back off if you will take a more subtle stance on your criticisms. I and a lot of others are getting tired of it.
Has it occured to you that this is just a hobby? Many people are not looking to gather information that is correct to an engineer or for someone with an engineering background. What we need to do is to educate without being overbearing. Just a simple explanation of what is correct and why.

Eric B.

PS: Peter we have been dealing with the snapshot of 3 numbers since I started this back in 1999. It is not wrong to go about testing this way, just the presentation needs a little dressing up so they are more meaningfull. Such as 14.4V, 33.3A, 475W whereas this will mathematically work.
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Last edited by AirX; Oct 10, 2012 at 07:21 PM. Reason: Added PS
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Old Oct 10, 2012, 08:17 PM
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I am 'engineering/technical' background. I am in this hobby. This means I can 'see' what things matter - how they work, why, and why not etc.
The majority of other users here can't.
So they are relying on the posts by whoever - someone that knows, or not - as guidance.
"I will buy that because he said this about it... posted these numbers etc"
"They said I 'need' that".
etc etc
They can't even tell if what as posted was actually correct, close, likely to be right, or quite amiss.

I even had to do that some amount at first, seeing it was a 'new' area of specifics for me (though I have the technology building blocks to work anything out).... very quickly to find that most info is not of true use, or fully correct. Lots are... lots aren't.
Wasting money basically, whether ending up with ineffective results, or things that would not have lasted if not for my ability to assess a setup in advance to know better.

So whilst the majority are not technical, and may not want to know details, it would serve them well if they DID know... make the effort to know. And that needs decent/accurate and useful info supplied in the first place. Otherwise you learn the 'wrong' stuff.
Then can end up like occurs now... more is just 'parrot fashion' info handed down from one to the next etc, and distorted, inaccurate, not complete enough to truly tell a story etc.

Criticisms....
Anyone that sees 'arrogance' or 'criticism' tends to have self-esteem issues themselves. Often seen when there is an interaction of 'higher intelligence' with another of 'less intelligence'. That is because the lower IQ cannot see and decipher the knowledge, its transfer, and instead they take it as an attack on their 'lack' of knowledge. "You are putting me down".
A higher IQ recipient LISTENS, and recognises what they didn't know, probably asks questions, but never takes the exchange as 'arrogance' or 'criticism'. Not unless it truly is criticism - which they can determine more accurately if it truly was or not. You can't determine things accurately if your base ability is lacking how to separate the factors properly in the first place.

You might feel like reading my X (100's) of posts, and you will find I never retaliate in 'Wahh, you were picking on me!". Even rarely 'retaliate' at all... just post back the reasons and 'facts' on why I disagree. Because I can always recognise that difference of what another person was truly TRYING to convey. Of course some are pure attacks on me... such as from those who 'sooked' over being 'criticised' (when it was not at all).... so seeing I can understand those responses too (unfounded by them, but I know why) I can just totally ignore them as not worth the time to sort out, or like even this case of yours (AirX) spend the time to further explain why... try to convey why it is not truly an attack (on Anlucas)... and even bother to do so at all.
From things I have read (posts) I see you DO know a lot. Thus 'worthy' of paying attention to... but it still needs 'checking' and verification, in case you error, or some bits you might not truly know. Or maybe, like above, have some bias in your response to support something not quite fully supportable... like a documentary might not truly be unbiased at all in many cases (but people just take as gospel)
LOL. delving into psychology now....
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Old Oct 10, 2012, 10:29 PM
EDF rules... :)
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Quote:
Originally Posted by PeterVRC View Post
I am 'engineering/technical' background. I am in this hobby. This means I can 'see' what things matter - how they work, why, and why not etc.

>Snip<

From things I have read (posts) I see you DO know a lot. Thus 'worthy' of paying attention to... but it still needs 'checking' and verification, in case you error, or some bits you might not truly know. Or maybe, like above, have some bias in your response to support something not quite fully supportable... like a documentary might not truly be unbiased at all in many cases (but people just take as gospel)
LOL. delving into psychology now....
Peter,

I dont mind being checked, I make mistakes just like you do.

Did you get the bifurcated exhaust sorted out for your F15, I seem to remember you were having a problem getting bench numbers from the CS70 in an installed high drag environment? Can you explain or post a link to your explanation? Have you figured out if your 90mm is going to fly with the setup you designed for it? Do you think that you might be able to figure out what you need in the fan if you would just take a few minutes doing a little math calculating 100% fan performance and comparing it to the setup you have on hand to see if you may have made the wrong choice in motor kv for the desired performance?
All this is possible to a very high degree of competency.
Lots of navel contemplating there mate.

One thing I do if I am looking for the right motor for the fan I intend on using is just that, work a little math. The result is I dont worry about flying so much and I usually get the performance I am looking for.

Eric B.

PS: I see your quite oblivious to the fact that a lot of people look at your posts and see confrontation instead of well meaning thoughtfullness.
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Last edited by AirX; Oct 10, 2012 at 10:36 PM. Reason: Added PS.
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Old Oct 10, 2012, 11:45 PM
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Oh man, all hell can break loose when someone is asleep...

Peace...

I don't think Peter meant to attack me. I undestand what he is saying but don't agree fully.

Just quoting results in a format that others have decided upon a long time before I ever decided to get involved in electric RC models....

Eric, gave the best description on how to interprete these numbers that most watt meters give.

I 'd be happy to adapt to whatever format the mass wants...
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Last edited by anlucas; Oct 10, 2012 at 11:55 PM.
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Old Oct 11, 2012, 12:01 AM
Extreme CNC Alloy EDF
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The very first paragraph in post 5337 reitterates the notion others are picking up on, vague quantification of qualifications, followed by a statement along the lines that most people in here dont have a clue.
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