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Old May 05, 2012, 03:01 AM
ich bauen groß modell flugzeug
Keenan smith's Avatar
United Kingdom, London
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Good To hear Jakob! Did you Get any Footage??

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Old May 05, 2012, 05:03 AM
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jakob k's Avatar
Danmark, Midtjylland, Horsens
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Boeing 737 Qantas på RCParken Søgaard (0 min 37 sec)


Boeing 737 Qantas på RCParken Søgaard (1 min 18 sec)


As you can hear and see from the takeoff then there is wind present:-)


-Jakob
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Old May 05, 2012, 09:33 AM
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Phaedra's Avatar
Belgium, Flemish Region, Duffel
Joined Apr 2012
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Nice going, Jakob !
Did you (have to) balance these EDFs ?
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Old May 05, 2012, 03:52 PM
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Quote:
Originally Posted by Phaedra View Post
Nice going, Jakob !
Did you (have to) balance these EDFs ?
oh yes.... and it took quite a while. I did it as sergey has made a tutorial about. luckily i had an extra set of housings, since one housing broke in the motor mounting while measuring with the accelerometer.

I hope you also can tell from the sound on the videos that I've done a quite a bit of work on getting them balanced. The only thing I would say is anoying is that I have a point about 30% throttle where they vibrate and its easy to hear. But from 50-100% they sound awesome, but still this is not an overpowered setup (eco set with 3800kv motor).

Doug>>>> How many KV are yours?


-Jakob
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Old May 05, 2012, 06:26 PM
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Joined Jan 2009
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Hi there,

concerning take-off from grass:

Here´s a video of my 737s´ maiden flight taking off from grass.

She is powered by 2 Wemotec minifans with Het 2W23 running on 1 5S 5000mAh battery.
Total static thrust is approx. 2,8 kg at 90 Amps. AUW 3,5 kg.

She has plenty of power and does not even need full thrust to take off from grass.

P1090659.MOV (0 min 15 sec)


Greetings

Michael
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Old May 05, 2012, 06:52 PM
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Doug W's Avatar
United States, WA, Seattle
Joined Jul 2010
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Quote:
Originally Posted by michi3 View Post
Hi there,

concerning take-off from grass:

Here´s a video of my 737s´ maiden flight taking off from grass.

She is powered by 2 Wemotec minifans with Het 2W23 running on 1 5S 5000mAh battery.
Total static thrust is approx. 2,8 kg at 90 Amps. AUW 3,5 kg.

She has plenty of power and does not even need full thrust to take off from grass.

http://www.youtube.com/watch?v=azGeN...hannel&list=UL

Greetings

Michael
First, excellent soft field take off technique and power reduction after rotation. I think you may have the most powerful W737 flying right now. HET2W-23 on a 5S? Whoa!
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Old May 05, 2012, 07:13 PM
ich bauen groß modell flugzeug
Keenan smith's Avatar
United Kingdom, London
Joined Dec 2010
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5s ?? Man you are Crrrrraaaaazzzzzy!
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Old May 06, 2012, 03:18 AM
Paul B
Australia, TAS, Launceston
Joined Dec 2009
352 Posts
Quote:
Originally Posted by michi3 View Post
Hi there,

concerning take-off from grass:

Here´s a video of my 737s´ maiden flight taking off from grass.

She is powered by 2 Wemotec minifans with Het 2W23 running on 1 5S 5000mAh battery.
Total static thrust is approx. 2,8 kg at 90 Amps. AUW 3,5 kg.

She has plenty of power and does not even need full thrust to take off from grass.

http://www.youtube.com/watch?v=azGeN...hannel&list=UL

Greetings

Michael
Thats good to see, mine will have just over 3kg of thrust and will be off grass. Gives me confidence.

Cheers
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Old May 06, 2012, 04:11 AM
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jakob k's Avatar
Danmark, Midtjylland, Horsens
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Quote:
Originally Posted by Pannoch RC View Post
Thats good to see, mine will have just over 3kg of thrust and will be off grass. Gives me confidence.

Cheers
What is your power setup?

-Jakob
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Old May 06, 2012, 05:28 AM
Paul B
Australia, TAS, Launceston
Joined Dec 2009
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Quote:
Originally Posted by jakob k View Post
What is your power setup?

-Jakob
I'm using Extreme RC's 10 blade fan combo, fully balanced in a custom alloy housing using HET motors with 80A ESC's. 1.5kg of thrust, 900W at 14.8V (each). Even more on 5s.

Always fly off grass so I need a bit of oomph to get of the ground.

Paul
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Old May 06, 2012, 04:45 PM
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jakob k's Avatar
Danmark, Midtjylland, Horsens
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Do you guys think I will be able to try 4c battery on Mings Eco set with 3800kv motor and 50A ESC?

If not what should I do.

Buy new batteries+ESC+Motors?

I really want to take off from our grass field!!!!

Ive read through this thread and what I can tell from ming's post then the 3cell setup with the 3800kv motors draw about 35A, so shouldn't I be safe to try 4 cells on the same setup? I will only give WOT for a maximum of about 5-10seconds.

-Jakob
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Old May 06, 2012, 08:26 PM
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Doug W's Avatar
United States, WA, Seattle
Joined Jul 2010
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Wedgetail Update

Progress today...raised the nose gear bay (as I did on the Alaska 737) to give the slightly nose down angle to the -700 when parked. Forgot how much of a pain that is as a mod. Ventral fins are done, nose gear is tested, battery hatch modified (I made it smaller) to accept the upper fairing (which is a half inch too tall in the photos- it will be recessed for structural intergrity into the fuse slightly)...engines are fit and test run, I just need to glue the cowlings togther.

First flight is in June...
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Old May 07, 2012, 09:43 AM
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Phaedra's Avatar
Belgium, Flemish Region, Duffel
Joined Apr 2012
716 Posts
Quote:
Originally Posted by jakob k View Post
Do you guys think I will be able to try 4c battery on Mings Eco set with 3800kv motor and 50A ESC?

If not what should I do.

Buy new batteries+ESC+Motors?

I really want to take off from our grass field!!!!

Ive read through this thread and what I can tell from ming's post then the 3cell setup with the 3800kv motors draw about 35A, so shouldn't I be safe to try 4 cells on the same setup? I will only give WOT for a maximum of about 5-10seconds.

-Jakob
According to Windrider's own website, you can run this motor on 4S :

http://www.windrider.com.hk/product.asp?id=197

They talk about 30A on 3S, and 46A on 4S.
This means that you can run it on 4S, but you need another ESC to be safe. Some say you need some 25% margin on your ESC, but as you state it, you wouldn't need this current all the time.
I would suggest to run the motor + EDF combo with a power meter and get an idea of the current for each motor regime, and monitor the temperature of the ESC.
Another risk might be the higher RPM, since you have a higher voltage with 4S. Question is if the EDF unit is solid enough for this extra RPM.
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Old May 07, 2012, 09:59 AM
Don't Move I've Dropped My Nut
bamaguy's Avatar
United States, AL, Huntsville
Joined Feb 2009
1,659 Posts
Quote:
Originally Posted by Phaedra View Post
I would suggest to run the motor + EDF combo with a power meter and get an idea of the current for each motor regime, and monitor the temperature of the ESC.


Another risk might be the higher RPM, since you have a higher voltage with 4S. Question is if the EDF unit is solid enough for this extra RPM.
Short bursts with 50amp ESC should be O.K. But I would use a separate power source for receiver/servos/retracts.....that will keep some heat out of the ESC.

The fan unit will be fine on 4S (mine are still working!)
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Old May 07, 2012, 10:02 AM
Ming's Avatar
Hong Kong
Joined Jun 2002
4,624 Posts
Suggest to short trim the grass.

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