XF fan at hobby lobby on 4s??

[Maine_flyer]

I have that ducted fan on a stryker frame and it flies well on 3s, more than enough thrust to hand-launch and flies it at approx. 60-70mph.. nice little unit, draws 22amps wot and 240 watts... comes down quite cool and seems like it can take more voltage.. have done some short bench tests with 4s with amp draw at 32 and 350 watts+ ... test bursts were short cuz the spec didn't (actually I can't find factory specs) say anything about 4s voltage... after a few bursts on 4s the motor was just warm to the touch, which I didn't find surprizing for static testing..

so my question to you is: has anyone been running this unit or motor on 4s? ..

the fan unit (http://www.hobby-lobby.com/ductfan.htm)

the motor (http://www.hobby-lobby.com/brushless-eth.htm)

thanks for any help youz can provide!:cool:

[Maine_flyer]

got an email from the folks at HL... thats a big negative on the 4s with that motor..

oh well.. I guess it's time for a little exhaust/thrust tube mod then... until this motor (http://www.x-flight.hk/e/products/productdetails.asp?ic=DF210_8XL) comes in :) :) ..thanks to Rocky @X-flight

[Stryker]

...just a comment...
I'm using the same fan and motor, managed to squeeze out 646 watts with 4 cells, 44 amps, 64 miles in horisontal flight, motor life less then 30 minutes...
Sound is "magic" but(t)...

[Bmiller]

Fan unit can handle it but the motor can't. Gets too hot inside and frys.
LS JETSCREAM outrunner comming soon from H-L will handle 4S in that fanunit. Haven't checked H-L site in awhile. may be available already.
Don't confuse it with a parkjet motor.

[termite]

I think you can order the Jet Scream from the ME-262 page:D

I'll probably be stocking them and the FX Fan soon!
Randy
Dynamo Electrics

[Maine_flyer]

...just a comment...
I'm using the same fan and motor, managed to squeeze out 646 watts with 4 cells, 44 amps, 64 miles in horisontal flight, motor life less then 30 minutes...
Sound is "magic" but(t)...

yow! that sux! ..glad I didn't keep testing the 4s.. thanks for posting that. it's a nice motor for the app.. and suits this one well .. but like you I wanted more speed.. I did manage to tape on a slightly smaller thrust tube (styro cup) to bench test this afternoon.. .. I've reduced it to 47mm but amps and watts are the same.. hmmmm

so wuz there at least a cool puff of smoke!??

[Stryker]

Hello Maine Flyer, the reason behind why I posted my comment was to hopefully save one motor for you…

Regarding smoke etc:
Everything was fine during flight, no sign of problem at all, wasn’t pushing the motor and kept throttle at 40-60%, and was testing out a new exhaust tube.
Test result was as expected - increased exhaust velocity (= higher speed) and first sign that something was wrong was a smell of burned electrics after landing…

Please check out the following general rules about ducted fans that I saved some time ago, don’t remember where I got it from except that it was from a dealer, it will explain to you that thrust will decrease as an direct result of increased exhaust….
Happy flying



GENERAL RULES OF DUCTED FANS
Though GDF's and EDF's are intrinsically different in terms of how the fan is driven, the aerodynamics and rules of thumb of the ducted fan remain the same regardless of the power source. We've compiled a list of items and frequently asked questions that should be helpful to you in your DF jet flying. If there is something we missed , please let us know!

How a ducted fan works - Ducted fans operate as they sound: they are an internally ducted high performance fan which takes in air from the inlet opening and blows air out an exhaust tube to generate forward thrust. The air enters an impeller spinning at high RPM which propels pressurized air out of its exhaust at increased pressure and velocity. A ducted fan thrives on the air fed into it so too little air will starve the fan, thus preventing it from perform at its optimum design point. Conversely, inlets that are grossly oversized can have the same effect: a ducted fan can only process a given amount of air at any particular time, so too much air will hamper performance --not to mention the increased drag from the larger inlets.

Requirements for Ducted Fans - Ducted fans need inlets sized to approximately 95%-110% of the Fan Swept Area (FSA) with an exhaust outlet sized to approximately 75%-85% FSA. Choking down airflow at the exhaust, increases exhaust velocity. This in turn will increase top end speed of the aircraft. There is, however, a point of diminishing returns: choking down the exhaust too much will back pressure the fan resulting in degraded performance. Additionally, a larger outlet area will increase the static thrust of the system, but lower the top end speed of the aircraft. The areas suggested above represent a good compromise between static thrust and exhaust velocity.

Fan Swept Area - The fan swept area is calculated by subtracting the area of the impeller hub from the area of the inside of the shroud. The equation is shown below:

Duct Area - Impeller Hub Area = Fan Swept Area
External Inlet Shape - The ideal inlet lip shape for a ducted fan aircraft is a 2x1 ellipse. This represents the most aerodynamic shape while maintaining good airflow into the inlet system.

[ParkJetsFlyer]

I think you can order the Jet Scream from the ME-262 page:D

I'll probably be stocking them and the FX Fan soon!
Randy
Dynamo Electrics
I have a X-Flight F-22 that those fan's will fit in perfectly. :)
I bet that fan would work in a Flying Styro F-16 but you'd probably need that cheater hole :(