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Old Feb 19, 2012, 07:41 AM
Leventx
Joined Jul 2011
35 Posts
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Need Advice for edf location on the plane???please...

Hi To All,

I m in a big confusion after flew with my Jet Legend f-16 with vasa 120 (12s 30c 6200mah , cc 160hv)

other 2 guys flew same plane with jet joe turbines just before me, one of them has 4.8kg and other is 5.5kg thrust only ,,on the ground even with worst 12s batteries i have 5.6kg thrust with my vasa 120 edf...

at the take off i pushed full throttle and my plane took off after run around 150-200meters than i could climb up with 20degree angle only, from 1.5min minute of flight my plane even can not climb up because thrust was not enough.i did 3 min flight and than landed succesfully, while flying even i afraid to gear up, i was thinking can be something happen and will not have time to let them down before land.

i was use to fly with not enough powered sailplanes so i manage to flew and land succesfully today

my edf is just located on the tail of plane to get rid of duct(intake) and .exhaust...
but i made so many holes back , under the plane to let enter more air in..

please guys,give me some advices, now i have confusion,

if edf on the back side, intake air is very enough for fan but cable between battery to motor is 100cm long
if i remove my edf to middle of the plane than cable will get shorter but intake is not enough...jet legend intake is very small tough...

so which one is better? if back side cable long so thrust maybe not enough ?

if its middle it ll be not enough again because air entering not enough ?

so what to do ?

Thanks
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Old Feb 19, 2012, 07:57 AM
Registered User
England/uk
Joined Oct 2007
520 Posts
jet legend F16

Hello,
Hello firstly i would have mounted the edf in the normal location not in the tail? then you will have a thrust tube and perhaps a bit more thrust. Also are all your lipos up at the nose? .
i understand that Jet legend gives you the option of a turbine in the tail or under the main hatch so i can see why you have done it .Full intake ducting is not required and a simple intake lip will work <Full ducting will work better>but its more work to make and install,
stick the edf under the hatch make a nice straight clean mylar tube and then try again??
cheers Euan.
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Old Feb 19, 2012, 08:30 AM
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USA, VA, Alexandria
Joined Oct 2004
359 Posts
Do you have an intake lip on the fan? You will lose a ton of thrust without one. Without a exaust thrust tube you are making static thrust but the air is moving slowly. So in the air you have very little thrust. You should have just mounted the fan further forward with an exhaust thrust tube and an intake lip. I probably would have flown fine. The holes on the bottom most likely just ruined the look of your plane.
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Old Feb 19, 2012, 08:44 AM
Leventx
Joined Jul 2011
35 Posts
thanks egall232,,

i think this is what i will do , remove the edf to middle of the plane again which is standart location for turbine...but do you have any photo or exact material to make thrust tube ? or how thick myler suppose ok ?

some pilots said, even can use X-RAY film for it, but i dont think its enough strong for 120mm edf

thanks
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Old Feb 19, 2012, 10:15 AM
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England/uk
Joined Oct 2007
520 Posts
jet legend F16

Hello,
drafting mylar works well if you can get it, i ended up using plastic PETG sheet from Hobbyking <the thicker of the two> as i struggled to get what i needed locally .X ray film will also work ,
cheers Euan.
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Old Feb 19, 2012, 10:52 AM
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EDF Crazy's Avatar
UK
Joined Oct 2007
634 Posts
Put your fan mid mount under the fan hatch and install a thrust tube and an intake lip. this is how i did it on my skymaster f-16.

Here is a video with a vasa fan in a skymaster f-16, i think with an intake lip also. The performance is quite decent.
Skymaster F16 Vasafan 120 neue Version (5 min 20 sec)
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Old Feb 20, 2012, 09:14 AM
Leventx
Joined Jul 2011
35 Posts
great thanks for help,,

i checked the photo and also videos about f-16, soon i m moving my fan to middle with thrust tube with adding intake ring

thanks
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Old Feb 20, 2012, 03:46 PM
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Joined Jan 2010
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Quote:
Originally Posted by paratechx View Post
thanks egall232,,

i think this is what i will do , remove the edf to middle of the plane again which is standart location for turbine...but do you have any photo or exact material to make thrust tube ? or how thick myler suppose ok ?

some pilots said, even can use X-RAY film for it, but i dont think its enough strong for 120mm edf

thanks
I used 0.4mm clear PVC on both of my 7.5-9Kwatt power units. Reinforce it well with fiber tape. 30C batteries are not good enough for any 120mm + EDF. Use min. 40+C for better performance, thats only MPO, Joe.
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Old Feb 24, 2012, 07:26 AM
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Wichita, KS
Joined Apr 2003
515 Posts
I have had good results using a section from a paper conical drinking cup for a thrust cone, cut it so to get the desired exit area.
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