Three bladed props anybody?

[SIMON CRAGG]

Chaps, any idea of the best / cheapest place to purchase 13" x 5/6 3-bladed props please?

[Jon H]

i/c or electric?

[SIMON CRAGG]

Electric please!

 

[Denis Watkins]

[Jon H]

Cant help with electric im afraid. The master props Denis posted are the ones i am familiar with but i suspect they would murder an electric motor due to their rather woeful efficiency 

[Colin Low 2]

4-Max offer 3 bladed props, which I'm using on my Mossie with no problems.

 

3 blade props from 4-Max

[SIMON CRAGG]

Gr8. Thx Chaps.

[Andy48]

6 hours ago, Jon - Laser Engines said:

Cant help with electric im afraid. The master props Denis posted are the ones i am familiar with but i suspect they would murder an electric motor due to their rather woeful efficiency 

I used one of the Master Airscrew 3 bladed prop with an electric model and found the performance very similar to a 2 bladed prop on the same model.

[Glenn Philbrick]

Colin

Mossie looks good is it a kit? I built the BT one some time ago but only lasted one flight as motor cut, I should like to build another but electric this time.

[Jon H]

36 minutes ago, Andy48 said:

I used one of the Master Airscrew 3 bladed prop with an electric model and found the performance very similar to a 2 bladed prop on the same model.

 

It gets complicated by RPM, but the basic issue is the master props are inefficient and on electric your current draw is likely to skyrocket vs the equivalent dxp electric prop.  

[Paul De Tourtoulon]

I used the bigger 'drone' props on my Electric Mosquito.

[Andy48]

3 hours ago, Jon - Laser Engines said:

 

It gets complicated by RPM, but the basic issue is the master props are inefficient and on electric your current draw is likely to skyrocket vs the equivalent dxp electric prop.  

That's just it, current draw was pretty much the same as with a 2 bladed prop. I have full telemetry on all my models, this is the log of that plane, weight 2.5k running on a 4S 3000mAh battery. Full power just over 50 amps which is as expected, and general flying at just under half throttle around 20 amps. Almost exactly the same as some of my other models of that weight and setup but with a 2 bladed prop. Current is shown in red, and clearly doesn't skyrocket. 

 

 

 

Here is another model, same power setup exactly, both models similar drag and wing loading. Looking at these logs it would appear that at lower power, the 3 bladed prop is better.

 

Edited December 6, 2022 by Andy48

[Jon H]

which 2 blade were you using? if it was another master then that stands to reason. 

 

also what rpm are you running on the motor? Masters fall off significantly at higher rpm

[Martin Harris - Moderator]

Is this for ground clearance or scale appearance?  If the latter, you won’t know the difference in use and you could put the Masters on, suitably decorated, should you want to put the model on static display. 
 

2 bladed propellers are more efficient than 3 bladers so if performance is important then I wouldn’t bother with multi-bladed props. 

[Simon Chaddock]

I used these 9x6 on my Bombardier Q400.

More as a token than true scale as they should be 6 blade!

At the time they did CW & CCW versions but don't seem to now.

It mangers pretty well on them.

[Colin Low 2]

20 hours ago, Glenn Philbrick said:

Colin

Mossie looks good is it a kit? I built the BT one some time ago but only lasted one flight as motor cut, I should like to build another but electric this time.

Glen, It's a much-modified Tony Nijhuis 46" Mossie. Electric powered, with electric retracts and a more rounded/shaped fuselage.

[Glenn Philbrick]

Thanks Colin

I will have a look, maybe for a winter build.

 

[Andy48]

21 hours ago, Jon - Laser Engines said:

which 2 blade were you using? if it was another master then that stands to reason. 

 

also what rpm are you running on the motor? Masters fall off significantly at higher rpm

I tend to use low kv motors wherever possible, and I have converted over to electric Masters for many planes. Get really good all round performance, take-offs at half throttle usually, and vertical flight if I need it. Maximum air speed with these planes is between 60-70mph, they are not built for all out speed.  Practical experimentation shows they give a better static thrust compared to input power than most if not all other makes I've tried over the whole power range.

[Andy48]

20 hours ago, Martin Harris - Moderator said:

 

2 bladed propellers are more efficient than 3 bladers so if performance is important then I wouldn’t bother with multi-bladed props. 

Not my experience, see above. All depends on what you mean by performance.

[Frank Day]

I have a couple of Parkzone 49inch Mosquitos, one has never flown and the other has had more than its fair share of mishaps before i bought it of course! So was a prime candidate for some tinkering.  Standard props are  8.25 x 5.5 2 blade with mini-me brushless motors. Goes really well but the those wee little chopped off square props had to go for something more scale, after all the little UMX version has 3 blades.

 

Bit of a measure up to see what size I could squeeze in and just searched for three blade props in that size, Ended up with 10x5 or 7 3blades from, I think a Durafly B17 in sets of 4,  normal and counter from Banggood.  with 2836 850kv's shoehorned in. Goes very nicely with less whine and better sound. Bonus is a bunch of spares for the Hangar Queen.

 

But really just search for models with similar spec and someone will have done the hard work for you. I still did some work on the stand with the Watt meter with a couple of different spec motors. I tried some MAS electric/gas, too heavy and just really didnt do it