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Propeller 3 Blatt

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Mitglied
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There is a study on the advantages of using propellers 3 blades instead of traditional propellers 2-blades ???.



In Spanish:
Existe algún estudio sobre las ventajas de utilizar hélices de 3 palas, en vez de las tradicionales hélices de 2 palas???.



Thanks / Gracias
Mitglied
Registriert seit: Apr 2010
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Ort: Köln
This isn`t new.

We often use 3 blades propellers with big modellplanes. The reason is less noise.
You have to reduce the size of the propeller.
For example. 2 blades 12x4 goes to 11x4 3 blades.

The problem is to buy propellers with 3 blades in the size you need.
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Registriert seit: Jun 2012
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Thanks/Gracias Tom60.

Thanks for the information. I have a MK Okto2 XL with engines MK3638 and propellers of TMotor 12x4 ' of 2 blades. With camera and 2 batteries of 5. 000, weighs approximately 5,2 kg.
According to MK tables,this engine, (not the frame) could with normal propellers 14".

If I change the propeller of 2 blades for the 12x4" for the 3 blades, what would be the effect, the benefit or harm?.


In Spanish:
Gracias por la información.

Yo tengo un MK Okto2 XL con motores MK3638 y hélices de TMotor 12x4" de 2 palas. Con cámara y 2 baterías de 5.000, pesa unos 5,2 kg. Según las tablas de MK este motor, (no el chasis) podría con hélices normales de 14".

Si cambio las hélices de 12x4 de 2 palas por las de 12x4 de 3 palas, ¿cual sería el efecto, el beneficio o el perjuicio?.



Tom60 meinte
This isn`t new.

We often use 3 blades propellers with big modellplanes. The reason is less noise.
You have to reduce the size of the propeller.
For example. 2 blades 12x4 goes to 11x4 3 blades.

The problem is to buy propellers with 3 blades in the size you need.
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Registriert seit: Oct 2007
Beiträge: 322
Ort: Schweiz - Winterthur
Zitat aus "Faszination Quadrokopter" von Roland Büchi:

Für einen Dreiblattpropeller vergrössert sich der Schub bei gleicher Drehzahl etwa um den Faktor 1.4 und die Leistung etwa um den Faktor 1.6 verglichen mit einem Zweiblattpropeller gleicher Bauart.

==> Das heist einer mit 3-Blatt Propeller ist weniger Effizient als ein 2-Blatt Propeller!
==> Three blades propellers are less efficient then the same propoeller with two blades!
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aerorec meinte
I have a MK Okto2 XL with engines MK3638 and propellers of TMotor 12x4 ' of 2 blades. With camera and 2 batteries of 5. 000, weighs approximately 5,2 kg.
According to MK tables,this engine, (not the frame) could with normal propellers 14".

If I change the propeller of 2 blades for the 12x4" for the 3 blades, what would be the effect, the benefit or harm?.

3 blades propeller gives more power (lift) than the standard 2 blade propeller, but it is less efficient (shorter flight time).

For the Okto2 XL the mass 5.2 kg is quite heavy. An alternative to 3 blade propellers is to use larger propellers as you mention yourself.

The standard okto frame is square (diamond) shaped with 4 short and 4 long riggers. You can use larger 33 cm propellers instead of the normal 30 cm propeller, if you change the 4 short riggers to 460 mm long riggers. This gives a circular (radial) layout. I recommend to use the stronger version riggers with 1.5 mm wall thickness. I recommend also to use carbon center plates 2 mm from Altigator, unfortunately MikroKopter only sell thin 1.1 mm center plates. For circular layout use the same motor angle adapters for all motors. FASE G2 micro-copter use circular layout and fly well with a typical MTOM of 5.7 kg.
« Bearbeitet von Foersom am 30.10.2016 01:05. »
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Tom60 meinte
We often use 3 blades propellers with big modellplanes. The reason is less noise.

The less noise, I presume that is due to the propeller turning slower. Correct?
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Thank you all for the answers.

Foersom, I've had that configuration in another Okto Xl. But the OKto2Xl with 4 short arms is very comfortable to carry in the trunk of my car.

The goal is greater autonomy. If the arms could fold without increasing much weight, it would be a great solution.

I think MK should consider making the core larger diameter disks and with the same arms could use bigger propellers and all components would be more loose and cold. They should also market longer feet (landing gear).




In Spanish:
Gracias a todos por las respuestas.

Foersom, Ya tuve esa configuración en otro Okto Xl. Pero el OKto2Xl con 4 brazos cortos es muy cómodo para transportar en el maletero de mi coche.

El objetivo es mayor autonomía. Si los brazos se pudieran plegar, sin aumentar mucho el peso, sería una gran solución.

Creo que MK debiera plantearse hacer los discos centrales de mayor diámetro, así con los mismos brazos podríamos usar hélices más grandes y todos los componentes estarían más holgados y fríos. También deberían comercializar pies más largos (tren de aterrizaje).




Foersom meinte
aerorec meinte
I have a MK Okto2 XL with engines MK3638 and propellers of TMotor 12x4 ' of 2 blades. With camera and 2 batteries of 5. 000, weighs approximately 5,2 kg.
According to MK tables,this engine, (not the frame) could with normal propellers 14".

If I change the propeller of 2 blades for the 12x4" for the 3 blades, what would be the effect, the benefit or harm?.

3 blades propeller gives more power (lift) than the standard 2 blade propeller, but it is less efficient (shorter flight time).

For the Okto2 XL the mass 5.2 kg is quite heavy. An alternative to 3 blade propellers is to use larger propellers as you mention yourself.

The standard okto frame is square (diamond) shaped with 4 short and 4 long riggers. You can use larger 33 cm propellers instead of the normal 30 cm propeller, if you change the 4 short riggers to 460 mm long riggers. This gives a circular (radial) layout. I recommend to use the stronger version riggers with 1.5 mm wall thickness. I recommend also to use carbon center plates 2 mm from Altigator, unfortunately MikroKopter only sell thin 1.1 mm center plates. For circular layout use the same motor angle adapters for all motors. FASE G2 micro-copter use circular layout and fly well with a typical MTOM of 5.7 kg.
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aerorec meinte
I've had that configuration in another Okto Xl. But the OKto2Xl with 4 short arms is very comfortable to carry in the trunk of my car.

4 short arms? Do you mean 4 * 355 mm? That would be octo-copter with very small propellers.

aerorec meinte
The goal is greater autonomy. If the arms could fold without increasing much weight, it would be a great solution.

I think MK should consider making the core larger diameter disks and with the same arms could use bigger propellers and all components would be more loose and cold. They should also market longer feet (landing gear).

They are doing that with the Big Series and the MK8-3500. There the arms are detachable. However these copters are on another higher price level than the Okto2 XL.

If you want long landing legs for the MK alu frame, I can recommend these Altigator 33 cm.

About heat. The BL-Motor-Ctrl V2 get very hot when under heavy load and good ventilation is essential. However that is not a problem with BL-Motor-Ctrl V3 which runs cool even on much higher load.

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