3 bladed helis

[338federal]

Here is my 700/800 with 753 edge on main. Bank1 is about 750-850 rpm. Bank3 1300 rpm.

Align 700/800 tri blade (6 min 57 sec)

[trillian]

Looks good! You have the three blade tail as well :-)

[338federal]

Yes. Have before rc-tek 3 blade tail. Align is nicer and smoother. Now more tests. Hard wind today so no flight. Maybe tomorrow.

[im4711]

very nice

[rachel stinson]

Hi

There is a difference between 3 bladed and 2 bladed helicopters.
Many myths abound regarding multi blade props versus two,
one normally stated early in most threads about the subject is that more blades affect the airflow to others.
This is simply not true as shown by several photos in the thread referenced below.

Multi blade props when properly matched to a motor will provide increased performance as compared to a two blade prop!
Of course a 3-blade propeller is going to give you more thrust than two, and a 4-blade more than a 3-blade.

The issue is EFFICIENCY. Three blades will not give you 1.5 times the thrust of two.
Four blades will not give you 2 times the thrust of two. As you add blades, the losses increase exponentially;
the prop becomes less efficient overall, but it does increase performance.

Thank you

[FR4-Pilot]

So, do 3 bladed helis perform better or worse than 2 bladed helis at low RPMs? Given the same heli - the only differences being the head/blades/swashplate ?

- John

[trillian]

It depends on a few different things. With three blades you can have a totally rigid head and not get any nodding in a hover. The advantage of a rigid head is very quick cyclic response.

You have more moving mass due to the weight of the third blade and you also have the additional drag, so in theory at least you lose a little flight time IF everything else stayed the same, but you also don't need to use as much pitch. In my experience with 700 size helis, one being three blade and the other two being two blade, I don't see a big difference in flight times but this will vary depending on your flying style (and I am taking into consideration that my two-blade helis happen to be much lighter airframes).

The extra spinning mass adds a feeling of stability and the three blades seem to run super smooth. But you don't get that nice 'thwacking' sound at low headspeeds :-(

The only downside really is that not all three blade sets will fold back far enough, so if you have to remove a blade for transporting it's a bit of a hassle. With the Minicopter Triabolo running the NHP blades they will fold back neatly into the blade holder.

My Triabolo is the single best flying heli in my collection. That may not be due to the three blades, I don't know, but I suspect it's a factor because you get a great combination of stability and 'locked-in' feeling along with very good agility - the penalty being in the form of a bit of weight and drag.

Originally Posted by FR4-Pilot

So, do 3 bladed helis perform better or worse than 2 bladed helis at low RPMs? Given the same heli - the only differences being the head/blades/swashplate ?

- John