RCU Forums - EDF THRUST!

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hello guys!

i'm going to build an rc EDF plane and i have a question....
what thrust has to have the EDF so it can flyes?
for example if it weights 300gr-500gr-750gr-1000gr??

thanks a lot!

If you are talking a kinda standard jet plane and not something like a U2, you can try to shoot for a thrust to weight ratio of about 0.7 ... 0.85 would be very nice. So if the plane is 1kg, you want to try to get about 700g of thrust.

hey guys...wanted to say hello, and say this...power to weight ratio is relative to wing loading. A high wing loading and high power loading make for a marginal plane.

My 3 pound foamie jets like the LX F-16 like 1000 watts. fly marginal on 750 watts. I suppose fan efficiency is very important. WeMoTec fans are very good efficiency. The HET Fan is rather good too. I'm trying a new one, from Extreme RC in Australia, a China "Skyworld" 70mm cast alloy and 8 blade rotor. The rotor is frp or cfrp ? and has a turned alloy spinner, nicely balanced, hard to improve upon.

As soon as I've used the fan in a plane in actual flight I'll post more info

Quote:

ORIGINAL: tIANci

If you are talking a kinda standard jet plane and not something like a U2, you can try to shoot for a thrust to weight ratio of about 0.7 ... 0.85 would be very nice. So if the plane is 1kg, you want to try to get about 700g of thrust.

so if i put an 64mm EDF whith a motor which produce 520w and 1100g of thrust i will be ok in 1kg plane??
the kind im going to built is an L-39.

Whitedeath ... 1kg of thrust on a 1.1kg plane would still be very ok! Most of the turbines are happy to fly on a 0.8 thrust to weight ratio.

The thrust output from a 64mm running 520 watts, can't be even close to 2.4 pounds. You have a fan unit available that can take 520 watts to produce that thrust? From a prop yes, a 64mm fan no, to my experience.

Just for a laugh I went to Motocalc and tried a 65mm fan at ~550W: there is no GWS 64mm in the database.... sadly this comparably-sized Graupner fan produces nowhere near your 2.4lb (38oz)... you probably need 900W to get 38oz from a 64mm fan.

Motor: Feigao 540L 8T (5408408L); 3072rpm/V; 4.1A no-load; 0.0076 Ohms.
Battery: Thunder Power TP3300 (G4 ProPower 30C) (30C); 4 cells; 3300mAh @ 3.7V; 0.005 Ohms/cell.
Speed Control: Castle Creations Phoenix 45; 0.0026 Ohms; High rate.
Drive System: Graupner 1380; 2.3x3.36 (1.2in hub); (Pcoeff=1.015; Tcoeff=0.95).
Airframe: Anything you want.

Motor Amps = 39.9
Motor Volts = 13.9
Input (W) = 553.4
Fan RPM = 41651
Thrust (oz) = 27.6

Motor: Feigao 540L 8T (5408408L); 3072rpm/V; 4.1A no-load; 0.0076 Ohms.
Battery: Thunder Power TP3300 (G4 ProPower 30C) (30C); 5 cells; 3300mAh @ 3.7V; 0.005 Ohms/cell.
Speed Control: Castle Creations Phoenix 45; 0.0026 Ohms; High rate.
Drive System: Graupner 1380; 2.3x3.36 (1.2in hub); (Pcoeff=1.015; Tcoeff=0.95).
Airframe: Anything you want.
Motor Amps = 56.7
Motor Volts = 16.9
Input (W) = 956.8
Fan RPM = 50480
Thrust (oz) = 40.6