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 ?

More than 1 prop distance between the prop tips, increases stability. Less than that increases agility. So half to 1 prop distance is recommended.

1 prop gap diagonally between the two props

Thanks for the reply

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?

building a hexa, VC sir? sweet ) love hexas.
please post a build log please

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.

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?

IMO it doesn't really matters. Check Russian Chinook heli design, their blades overlap each other.

Sir, as the prop to prop distance increases, the inertia increases. Hence, slower response to stick inputs but better stability.

Veloci - Thanks Buddy.

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.

.

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.

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.

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