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Title: Effect of gap between to propellers in multi rotor Post by: Robologix on June 24, 2013, 04:11:31 PM :banghead: :banghead: :banghead: :banghead:
can some one explain the effect of the distance between 2 side by side propellers in the multi rotor is there an optimum distance to be maintained ? Title: Re: Effect of gap between to propellers in multi rotor Post by: veloci on June 24, 2013, 04:16:26 PM More than 1 prop distance between the prop tips, increases stability. Less than that increases agility. So half to 1 prop distance is recommended.
Title: Re: Effect of gap between to propellers in multi rotor Post by: pravesh736 on June 24, 2013, 05:45:09 PM 1 prop gap diagonally between the two props
Title: Re: Effect of gap between to propellers in multi rotor Post by: Robologix on June 27, 2013, 05:44:04 PM Thanks for the reply
Title: Re: Effect of gap between to propellers in multi rotor Post by: VC on June 27, 2013, 06:41:11 PM Pravesh/Veloci and all the other Champs - just checking if I got this right :
If I am using 10X4.5 blades on a Hexa then the gap shown in red should be approx 10 inches. Am I right? Title: Re: Effect of gap between to propellers in multi rotor Post by: Rahulvyas on June 27, 2013, 06:46:14 PM building a hexa, VC sir? sweet :)) love hexas.
please post a build log please Title: Re: Effect of gap between to propellers in multi rotor Post by: pravesh736 on June 27, 2013, 07:35:47 PM Hi VC Sir, the gap should be 10 inches minimum with 10 inch props between motor labelled 1 and 2 and not in between motor 3 and 5, between 3 and 5 its more than enough if u have a gap of 1/3 the prop size. :)
Title: Re: Effect of gap between to propellers in multi rotor Post by: VC on June 27, 2013, 07:42:25 PM Thanks Buddy. Tried calling you but your cell was switched off.
10'' minimum gap understood. Is their any maximum? What happens if the gap is say 20" between 1 and 2 - and say, 10" between 3 and 5? How will it affect the flying characteristics? Title: Re: Effect of gap between to propellers in multi rotor Post by: Dharmik on June 27, 2013, 09:57:11 PM IMO it doesn't really matters. Check Russian Chinook heli design, their blades overlap each other.
Title: Re: Effect of gap between to propellers in multi rotor Post by: veloci on June 27, 2013, 11:06:14 PM Sir, as the prop to prop distance increases, the inertia increases. Hence, slower response to stick inputs but better stability.
Title: Re: Effect of gap between to propellers in multi rotor Post by: VC on June 28, 2013, 12:27:00 AM Veloci - Thanks Buddy. :thumbsup:
Dharmik: 1. The Chinook isn't 'Russian'. It is manufactured by Boeing. Boeing CH-47 Chinook. 2. Even though the blades overlap, they are at different levels. 3. Quoting from Wikipedia - "Tandem rotor helicopters have the advantage of being able to hold more weight with shorter blades, since there are two sets. However, the rear rotor works in the aerodynamic shadow of the front rotor, which reduces its efficiency. This loss can be minimized by increasing the distance between the two rotor hubs, and by elevating one hub over the other." It pays not to fire from the hip while posting on this forum. Title: Re: Effect of gap between to propellers in multi rotor Post by: K K Iyer on June 28, 2013, 12:37:38 AM .
Title: Re: Effect of gap between to propellers in multi rotor Post by: VC on June 28, 2013, 01:05:19 AM Begging your pardon Sir, that question doesn't merit an answer here. Google the term for an explanation. FYI I am not referring to flatulence.
Title: Re: Effect of gap between to propellers in multi rotor Post by: Dharmik on June 28, 2013, 08:00:30 AM I believe the only reason to keep distance between two props(for multis) is for future upgrades(8 inch to 9inch or 10inch). I think it's more depends on the prop size.
Title: Re: Effect of gap between to propellers in multi rotor Post by: Robologix on June 28, 2013, 11:18:27 AM Hi i have got this explanation from arducopter
The more the the gap from propeller to propeller the less will be the copter stability due to wind and external factors as the cone formed between two props is large the optimum distance between two props is 3-4 inches for heavy lifts and 5 inches for normal ones for the copter to respond correctly to stick inputs with out much delay and it increases the resistance to external forces like wind |