The best prop?

[txdragin]

Hello all my fellow pilots. I have a quick question.. To all of yall who still fly stock motors on lipo batteries what, in your experience, is the best propeller for leisurely flying of the cub?

[patmatgal]

Lots of people say a 10 X 6 works best with a stock motor and Li Po. Got the same set up and can say an APC 10 X 4.7 was OK, but seemed lacking, went back and tried the stock 10 X 8 and it was "better" but soon burned out the motor. Got an MAS 10 X 6 prop for nitro planes (those props are DURABLE) but will try an APC 10 X 6e if I find one at the LHS.

[paulharris]

When I first went to Lipos, I couldn't find any 10 x 6 props fast enough, but was able to put my hands on a couple of 10 x 7s. I was very impressed with the performance, and only used WOT momentarily for ROG takeoffs. Cruised very nicely at half throttle. Then I got a package of 10 x 6s and continued to 'prop down.' Kinda disappointing, like running in second gear all of the time. I may go back to 10 x 7, but both seemed to work okay with the stock motor.

Paul

[ginginho]

Throttle mamagement is the key. If you've got it, then you can fly on the stock prop as long as you are steady. If you've not got it, you do need to prop down. If you are WOT a lot or all of the time, then you need to prop down to a safe size, which I believe (Fly will know ) is a 10x6.

[flydiver]

Electric motors are a constant speed device. They are rated in KV (RPM in 1000's/volt, no load). Give them current and they try to reach speed appropriate to voltage. As you load them (prop) they start to slow down. At about 3/4 of whatever would be the unloaded KV for that voltage seems to be the most 'efficient' prop size. You can continue to put on larger props and get more thrust but efficiency (power in vs power out) starts to decline. As the load continues the motor can't cope and slows down more. Excess power turns to heat and is wasted. A motor that smells or is too hot to hold after flying is certainly in this zone.
Continue to push prop size and the heat increases. As temps go up resistance in the motor windings goes up. This can become a rapidly increasing cycle and literally fry your motor in seconds if the ESC or battery don't cave in first.

So, can you get away with it? Sure-to a point. Is it actually a good use of the power available? That's up to you. A seriously over propped plane is a plane asking for a bigger motor. A grossly over propped motor is not long for this world.

[Dillzio]

The super cub LP comes with a 9x6 propeller stock, but it recommends that if upgrading to the Floats, you need the high powered propeller too (part PKZ1005)

I take it that this means that if you do install the optional floats, you have to be careful not to use too much full throttle or you'll burn out the motor & ESC/receiver?

These things really should be in the manual!

[flydiver]

What isn't in a PZ manual far exceeds that what is. Even so we get questions all the time clearly indicating even that puny manual is not read. This is a man's sport after all-we don't need no stinking manual.

I've talked to Horizon 3x about this. One thing they either do not have or at least admit to is specifications above and beyond the advertised ones.

One CSR did allow as how the new LP Cub RX/ESC has a different part # than the old one indicating a different product. Redesigned for more amps? Same one with the jumper removed to not confuse customers? He didn't know.

I can tell you it's the SAME motor. Specs for that motor ARE known even if HZ won't specify. You could upgrade all the other electrics and put a 50A ESC in there, THEN that sucker wouldn't burn up if you over prop. The motor still will though. $10 motor, your call.

[Dillzio]

What would generally have more power? A 9x7 or a 10x6? Both seem like a good step up from stock, but I'm just wondering which one would be a BIGGER step up?

[patmatgal]

The 10 X 6. I just switched from an MAS 10 X 6n prop on an E Flite 450 BL to an APC 9 X 7.5 SF, on the same motor. The MAS prop is much more durable and can take less than ideal landings much better (don't break) but the APC is a lighter prop and draws less amps so I get to fly longer. The APC prop takes a little more throttle (but draws less amps) for the same performance and both will easily pull the plane along much faster than the scale flying of a Cub (puttering around the sky) Sorry that this is kind of vague, lots of people swear by the GWS 10 X 6 but my LHS carries MAS and APC so most of my experience has been with those 2 brands.

[Dillzio]

Thanks for the tip!,

I just weighed the props too, and the GWS 10x6 is actually lighter than the stock one! Also thinner, so you need an extra nut to space it out a bit so it doesn't rub the cowl.

[patmatgal]

Picked up an MAS 9.5 X 6 yesterday, the MAS 10 X 6 is getting pretty ragged. Decided to swap props while flying this morning, only flew 1 battery with each size prop but the MAS 10 X 6 definitely produced more thrust.

[Legot]

Quick question, on a stock SC(not LP) would a four blade work? It would probably not have enough thrust to take off, but I dont know.


www3.towerhobbies.com/cgi-bin/wti0001p?&I=LX1635&P=7

Thanks
~Legot~

[flydiver]

As blade number goes up, size and/or pitch need to come down. So 10x8 is stock, 10x6 4-blade is WAY too big.
As blade # goes up efficiency goes down. Primary purpose is for planes that do not have sufficient ground clearance.

www.mh-aerotools.de/airfoils/propuls2.htm

[Legot]

Ok, thanks, now I get why Impellers alwys have multiple blades, and why cubs dont.

~Legot~

[flydiver]

EDF's (enclosed ducted fans) are merely small multi-blade props in a tube. They are used for sound (either a cool noise or an awful racket depending on your opinion), and looks-they make a jet look like a jet without a prop hanging off. In fact they are far less efficient than a double blade prop hanging out.