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Old Jun 14, 2009, 06:40 AM
b727-77 is offline
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Boeing 727-100 Gws-50 Edf

Gday, nearing completion of my TRI jet edf Boeing 727-100 which will have electronics installed very shortly, however i have just a few points to touch on, this is my first scratch built EDF aircraft i have built in 30 years of flying, (which has usually consisted of glo aircraft) and i was uncertain to a few things.
1. what volt and milliamp battery pack should i use to run: 4 HS-55 servos, and 3 GWS-50 EDF units.
2. where should my COG be? (very hard considering the swept back wing)
3.will these 3 EDF units be enough power for the aircraft ( im expecting the final product to weigh about 30oz)

thanks alot, il be sure to keep updating.
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Old Jun 14, 2009, 07:47 AM
Andrew McGregor is offline
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It would help a lot to know what motors you're planning on putting in those fans... or is that part of the question?
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Old Jun 14, 2009, 08:08 AM
b727-77 is offline
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Quote:
Originally Posted by Andrew McGregor
It would help a lot to know what motors you're planning on putting in those fans... or is that part of the question?

yes sorry the motors are not stock motors as i replaced them, the new motors are HXT 2040 (130L) 4850kv Brushless Inrunners.
thanks
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Old Jun 14, 2009, 11:53 AM
David A Ramsey is offline
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Quote:
Originally Posted by b727-77
i was uncertain to a few things.
1. what volt and milliamp battery pack should i use to run: 4 HS-55 servos, and 3 GWS-50 EDF units.
2. where should my COG be? (very hard considering the swept back wing)
3.will these 3 EDF units be enough power for the aircraft ( im expecting the final product to weigh about 30oz)
Hello again. Here's some thoughts:

BATTERY: Will depend on motor specifications. As to 4 servos; make sure your motor ESC(s) will support 4 servos.

CoG: 25 percent MAC is good. For a quick-n-dirty estimate; Using one side/half of your assembled swept wing, judge 25% of inboard swept wing panel at mid (50%) span cord. Do the same for the outboard swept wing panel. Half way between these 2 points will approximate 25% MAC of the whole wing. This will be close to a more careful assessment. Hope that was understandable.

3 EDF FANS??? I would go for only 2. A center/fuselage EDF that opporates with effeciency will be a nightmare to work out in your scale. You will be adding fan, ESC and battery weight. At best, I feel, the thrust from this fan may only support the weight it adds.

GWS press-on fans will not stay on a 1.5mm motor shaft at brushless rpms. You'll need an aluminum addapter. Currently, as far as I know, non are available. Heat is a consideration here also.

Keep your wing loading as light as possible. Thrust to weigh: (1 thrust) : (2 weight). 1:3 might work. 1:4 with a heavy wing loading isn't worth the effort ... in this size aircraft.

2 servos total; 1 servo each for ailerons and elevator should be enough. Avoid the weight of a landing gear.

Hope this helps a bit.
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Old Apr 14, 2015, 04:38 PM
M.Monsalve is offline
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Buenas Tardes, Seria posible conseguir los planos del Boeing 727 necesito llevar a cabo este diseņo para una clase de estructuras.
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Old Apr 14, 2015, 05:40 PM
turbonut is offline
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Welcome to RC groups

Google translation

Good afternoon , may Seria get Boeing 727 planes need to carry out this design for a class of structures .

Bienvenido . este es un hilo viejo y el cartel originale no ha vuelto a partir de 2010
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