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Duct fan THRUST????

Old 09-01-2020, 08:37 AM
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donnyman
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Default Duct fan THRUST????

OK I am not a E D F whizz and maybe I have missed what is the important info on duct fans, that being said, why isn't the thrust output given for these units?? I know the data will change with different batteries and such but I have been reluctant to purchase without the manufactures thrust info. whats up?

Old 09-01-2020, 09:19 AM
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Because its different with different c rated batteries and different ESC's

What specifically are you trying to accomplish?
Old 09-02-2020, 08:31 AM
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I understand that! I wont purchase anything unless I have some sort of info as to the capabilities of what I am spending my money on. What is the minimum and max thrust out put? all units are not the same, no matter the size, It appears this info should follow some sort of standard. The manufactures seem to use a haphazard set of parameters to sell their units and I have to rely on others to find out what a particular unit can do. I don't want to experiment and spend my money to get info the manuf. should supply.
Old 09-02-2020, 09:02 AM
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This the F-14 I saw in another thread?

Do yourself a favor, give Gary a call at E-Flux RC

He knows more about EDF setups than most of the rest of us put together.
Old 09-02-2020, 09:32 AM
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You are familiar with my f-14 build we have spoken before, but I am not seeking assistance with fan units I was just wondering why more info isn't available to the buyer. no matter what they call it if you want to "go" ya gotta have the thrust to do it! would you buy a turbine with out thrust data? it's like reading a long advertisement about a product but no price is given. which I find suspect.

I will keep Gary in mind if I need EDF INFO. Thanks
Old 09-02-2020, 03:23 PM
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You could try fanCalc
www.ecalc.ch
fanCalc

Vriendelijke groeten Ron
Without a watt-meter you are in the dark ... until something starts to glow
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Last edited by ron_van_sommeren; 09-02-2020 at 03:25 PM.
Old 09-03-2020, 03:52 PM
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It's more than just simple numbers. There's motor size, motor kv, brand of motor, lipo brand, mah. size, ducted versus open duct, the list goes on. No way to say for sure. Look at jet fan, Schubeler or Wemo. They gives all kinds of info on different parameters. Sounds like your not looking in the right area or your looking at cheap Chinese fans.
Old 09-05-2020, 01:30 AM
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Originally Posted by donnyman
OK I am not a E D F whizz and maybe I have missed what is the important info on duct fans, that being said, why isn't the thrust output given for these units?? I know the data will change with different batteries and such but I have been reluctant to purchase without the manufactures thrust info. whats up?
Only one way to find out about the true EDF thrust, hook it up in competed model and test it it.

There is only one thrust that counts, fitted inside the model.

Hook it up to test it.

Gives me good idea how will it fly well in advance.

Regular homework.

It's all in the log books.
Old 09-05-2020, 07:25 AM
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OK! I am aware of all that was said here. with the many variables inherent in these units we the purchasers determine the final output (thrust) of these units according to how it is utilized.
so then, what prompted you to purchase the particular unit you have? Size? weight? diameter? Info from someone else? guesstimate? or just plain luck? or All the above?
Old 09-05-2020, 05:34 PM
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Thrust depends on a lot of electrical and mechanical parameters, however, the manufacturer has no influence/say in the power system, and it is not their field of knowledge.
Specifying thrust as function of rpm hides/seperates those parameters nicely, just like with propellors. You don't specify an AC's cooling capacity by its wire diameter or the size of the holes in the mesh.
Having said that, I don't know why manufacturers don't specify EDF thrust/rpm numbers. Nah, for Chinese manufacturers it's probabably a simple explanation: the user is the tester.

Vriendelijke groeten en wees voorzichtig Ron
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e-flight calculators watt-meters diy motor tips&tricks Cumulus MFC



Last edited by ron_van_sommeren; 09-05-2020 at 05:38 PM.
Old 09-06-2020, 03:38 AM
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Originally Posted by donnyman
OK! I am aware of all that was said here. with the many variables inherent in these units we the purchasers determine the final output (thrust) of these units according to how it is utilized.
so then, what prompted you to purchase the particular unit you have? Size? weight? diameter? Info from someone else? guesstimate? or just plain luck? or All the above?
Mate, these days all you have to do is just a "click" with index finger, and you can find any info you are after on anything above. In my case, it's all about experience, building so many EDF models over the years with all the info in each model's log book.
Only few days ago started on 4 engine EDF jet build, the first thing I wanted to find out aprx. thrust of each unit, to give me an idea about the size of the air frame to cut out of Depron base.
I was rather conservative, making up the smaller frame before power units arrived.
Rather have more juice than not enough. Can't wait to hook it up to see what it pulls on the ground combined as "quadrosonic",

First check run gives me some idea about the thrust.

Circa-200 hour job in progress.
but after the first quick check run to see the current draw, I think I could have gone lot bigger.
(2B2 power unit check run)
Old 09-06-2020, 10:28 AM
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Originally Posted by ron_van_sommeren
Thrust depends on a lot of electrical and mechanical parameters, however, the manufacturer has no influence/say in the power system, and it is not their field of knowledge.
Specifying thrust as function of rpm hides/seperates those parameters nicely, just like with propellors. You don't specify an AC's cooling capacity by its wire diameter or the size of the holes in the mesh.
Having said that, I don't know why manufacturers don't specify EDF thrust/rpm numbers. Nah, for Chinese manufacturers it's probabably a simple explanation: the user is the tester.

Vriendelijke groeten en wees voorzichtig Ron
Without a watt-meter you are in the dark ... until something starts to glow
e-flight calculators watt-meters diy motor tips&tricks Cumulus MFC
We are in agreement, and Joseph Frost post confirms it in the very next post after yours. The things is the MANUF. needn't guarantee anything. only state what he got with his test setup, for me, those that don't give all the info is suspect.

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