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Old Nov 15, 2012, 04:15 AM
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Foam Jet 758 Grams Mass 500 Grams Thrust 90 mm EDF 14.5 Volts Turnigy 20 ESC

http://kiwitricopter.blogspot.co.nz/...-edf-with.html



500 Grams of thrust 90mm EDF with Turnigy L2210-1650



Cobbled together 90 mm fan with 250 Watt Turnigy L2210-1650 Bell Style Motor (250w) seeing if I can get decent efficiency from a small fan turning slower.

http://www.youtube.com/watch?feature...&v=Je9fi7cHIo4

[IMG]http://2.bp.blogspot.com/-Wlla615O3Nc/UKDMdP1-
_nI/AAAAAAAATfg/I_GuAgHymCQ/s320/IMG_2082.JPG[/IMG]

Weighs around 150 grams now.



On 14.8 Volts its pushing almost 500 Grams, not so bad thrust mapping is as follows.

100 Grams 1.9 A 27.6 Watts
156 Grams 3.0 A 42.9 Watts
197 Grams 3.9 A 55.1 Watts
257 Grams 5.5 A 76.0 Watts
296 Grams 6.7 A 90.9 Watts
340 Grams 7.9 A 105.5 Watts
432 Grams 10.7 A 138.1 Watts
492 Grams 12.5 A 155.7 Watts

The data in a spread sheet

The tests were run on two 7.4V 1300mAh Turnigy 20C Lipo's in series, I figure the motor will survive full throttle bursts on 4C and its 10 Amps short of the max, 100 Watts below its spec.

Its surprising as the same motor with a 8 X 6 prop pulled 23.3 Amps on a 3C yielding 520 Grams of thrust at 232.3 Watts.


Got this battery on its way from Hobby King Rhino 1550mAh 4S 14.8v 20C Lipoly Pack



Capacity : 1550mAh
Constant discharge: 25C
Burst rate: 30C (15sec)
Configuration : 4S 14.8v
Pack size: 100x34x26mm
Weight : 178.3g
Discharge plug: XT60

PRODUCT ID: R1550-20-4





I already had one of these units with a dead motor. On test I got 2.2 Kgs of static thrust, so the fan rotor has slightly better efficiency at 492 Grams as it does at 2200 Grams

High-Torque EDF Ducted Fan Unit 5Blade 90mm w/1600W Outrunner Motor


This is a powerful fan/motor combo that has been factory dynamically balanced leaving you to simply solder your ESC/motor connectors, fit and fly. The Pre-Installed 1900kv Outrunner Motor is rated for 6s meaning an impressive 2600g of thrust, an ideal upgrade for 90mm PNF models!
Fan Spec:
Outside Diameter: 92.5mm
Rotor Diameter: 90mm blade
Material:Fibreglass reinforced Nylon rotor
Max RPM: 45000 RPM
Thrust (6s): 2600g
Weight (Complete unit): 311g
Comes with optional inlet ring
Motor Spec:
motor: 35/48 1900KV brushless Outrunner
KV: 1900 rpm/v
Shaft: 5mm
Idle Current: 3.5A/11A
Resistance: 0.012ohms
Max Voltage: 22.2v (6s)
Max Amps: 70A

Need a plane for it should be pretty ugly with such a big fan

Thust 500 Grams
EDF & Motor 150 Grams
Battery 178 Grams

If the air frame can be built in 172 grams it will have an thrust to mass ratio of 1:1 pretty ambitious

@ 1:1.75 its 230 Grams
@ 1:1.5 its 344 Grams
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Old Nov 15, 2012, 04:20 AM
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Foam and Coroplast SPAD for the EDF Jet

Huge 90 mm jet pushing 500 grams on a 4C sort of a small 5 blade prop in this application.

See the test here

Some discussion in DIY Drones

A mass of 500 or 750 grams give a wing loading's of 13 oz/ft² and 19 oz/ft² respectively
Wing area 1.3855 ft²
Dihedral 5º
Kf2 A symmetric trapezoidal wings and tail plane
My Xbee based controller with appropriate RX software for the Jet



I will probably let the top stick out above the fuselage structure as its really a pusher prop in a tube. The jet location gives a neutral balance as is with out the tail and elevator or any servos



Could have inlets by the sides with an inverted boat as the top fuselage made out of Coroplast



Not sure there is anything to gain from having any sort of thrust tube yet, will test some ideas on the scales, and do some more reading. My intuition says keep the back low as possible behind the jet only the tail fin in the air flow and brace the structure from beneath. The 5º of dihedral gives some longitudinal stiffness so another V section in Coroplast running the entire length should do the job I think.



The foam in the nose section will probably go in favor of a more crash resistant Corriboard design.



Above is what I have in mind for the fuselage, this guy has the jet further back then me but I like the nose section. Of course I have a tail not just delta wings. Looks like he has done a good job of delivering a laminar flow to the jet intake, I will fit the lip as it gives about 30 grams of thrust.

If I sling the battery underneath I should have plenty of options for trimming the centre of gravity, as well as keeping it low compared to the motor which is mounted higher than the above example.

http://www.youtube.com/watch?feature...&v=fwYs-_VsEAg

The wings are braced with bamboo skewers cheap as. I will chamfer the top leading edges as that's what most people seem to do.

I am advised that the elevators will need lots of authority so I will fashion quite large ones



The Fan


Cobbled together 90 mm fan with 250 Watt Turnigy L2210-1650 Bell Style Motor (250w) seeing if I can get decent efficiency from a small fan turning slower.

On 14.8 Volts its pushing almost 500 Grams, not so bad thrust mapping is as follows.

100 Grams 1.9 A 27.6 Watts
156 Grams 3.0 A 42.9 Watts
197 Grams 3.9 A 55.1 Watts
257 Grams 5.5 A 76.0 Watts
296 Grams 6.7 A 90.9 Watts
340 Grams 7.9 A 105.5 Watts
432 Grams 10.7 A 138.1 Watts
492 Grams 12.5 A 155.7 Watts

The tests were run on two 7.4V 1300mAh Turnigy 20C Lipo's in series, I figure the motor will survive full throttle bursts on 4C and its 10 Amps short of the max, 100 Watts below its spec.

Its surprising as the same motor with a 8 X 6 prop pulled 23.3 Amps on a 3C yielding 520 Grams of thrust at 232.3 Watts.
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Old Nov 15, 2012, 04:23 AM
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Foam Jet 758 Grams Mass 500 Grams Thrust 90 mm EDF 14.5 Volts Turnigy 20 ESC

758 Grams with remaining Coroplast 2 X 7.4 V 1300 mAh batteries Arduino Nano RX Xbee with antenna, servos and misc hardware. Chamfered the top on the leading edges. All control surfaces cut and hinged. ESC mounted



Intake lip attached to fan intake.



Keel mounted



With its older brother

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Old Nov 15, 2012, 05:55 AM
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I build lot's plane's with EDF on top of wing from 30"in to 10'ft ck all my post. PS good job
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Old Nov 15, 2012, 06:00 AM
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http://www.rcgroups.com/forums/thumb...ttach&u=151599
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Old Nov 15, 2012, 06:09 AM
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I appreciate the appreciation this is my first jet I am intiged by the efficiency of what is after all a 3 inch prop on a 1650 Kv will be interesting to fly. Have a long weekend weather permitting I hope to flight it this week end
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Old Nov 15, 2012, 01:35 PM
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Love the planes, where should I set CG on my wee jet do you think?
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Old Nov 15, 2012, 04:28 PM
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25% back from leading edge at fuse maybe less you have big fuse. You could use short thrust tub
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Old Nov 15, 2012, 04:33 PM
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I have a short nose on it currently actually looks a bit stubby



How shorter thrust tube would you recommend? And should it tapper or any thing fancy?
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Old Nov 15, 2012, 04:43 PM
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6in'' mabey some tapper no more than 10deg. you need bamboo skewers across center of wings or they may fold
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Old Nov 15, 2012, 04:51 PM
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There is bamboo embedded between the KF layers in the wings they are quite stiff. Bamboo is an excellent material I was thinking about building an air frame from renewable s like bamboo, you can get it in a woven form which could be stretched over a frame perhaps
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Old Nov 15, 2012, 04:51 PM
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I assume the tapper would cause an increase in exhaust velocity ?
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Old Nov 15, 2012, 04:59 PM
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I whould think so' Iam no EXP
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