Help! Propeller Questions with SB Kit

[BSquared18]

Hi,

I'm near the end of building the Flyer from the three-pack swappable kit.

The motor supplied with the kit is the EMax Multi Copter Motor. It has a (red) spinner.

Supplied with the motor are two 10X4.5 props that fit on the motor shaft. Also supplied in the kit are some 9x4.5 props whose holes are too small to fit on the motor's shaft.

I've purchased some two-cell lipo batteries that I was planning to use on the Flyer. The ones I bought are 1000 mAh; Discharge: 20-30C. I bought them because they are super light-weight. To start off, I'd like to do slow flying. I was assuming I'd be using the smaller props.

So my questions are:

-- Why don't the kit-supplied props fit on the kit-supplied motor shaft?

-- With a two-cell battery, should I use the 9X4.5 or 10X4.5 prop? If the former, is there a way to fit it on the motor shaft?

-- Will two-cell batteries be too wimpy for this application? Will heavier, three-cell batteries make more sense even though they will be much heavier?

Thanks,
Bill

 

[BSquared18]

Me again. Now I realize from watching an FT video on propellers that larger propellers are used on slower flyers and vice versa. Learned something new. So, may I assume that I should use the 10X4.5 one, which DOES fit on the shaft?

Still curious why Flite Test would ship me some props that don't fit on the motor they provided.

Bill

 

[Hai-Lee]

Most props are shipped with a series of various inserts to suit different prop shaft diameters. The manufacturer just selects a generic hole size for the basic prop without adapter insert. For most of my props I have to either drill or ream out the centre hole to fit the prop adapter. Done properly it can be quite easy but if you get it wrong a mess can ensue. Always check the prop balance if you drill out the hub!

Have fun!

 

[BSquared18]

Always check the prop balance if you drill out the hub!

That kind of sucks.

Bill

 

[Gazoo]

Just to prepare you for disappointment later... You will most likely break the prop on your first time out too. Not to be a downer but that's the way it usually is. Hopefully you don't and have a great first flight.

I have drilled out many props to fit the shaft. I start with a slightly larger bit and then keep stepping up the bit size until the hole is large enough. Try to avoid drilling with the larger bit right away. Bad things could happen by taking out too much material at once.

I have never needed to balance a prop after drilling it out (or otherwise). The motor/prop combos that I use are not exactly high performance so there is some forgiveness. High RPM motor/prop needs to be balanced.

Always keep you body parts out of the plane of rotation. Props can and will explode.

If you bend a prop on landing, refuse the urge to bend it back and keep flying. The blade will eventually break and hurt someone.


That said, not too long ago I built the flyer. It flew really nice with a 2S 800mAh battery and 8X4 prop. It would have been even better with a larger prop like the 10X4.5. I was using a 20 amp ESC.

Post some pics if you can. They are always welcome.

 

[BSquared18]

Just to prepare you for disappointment later... You will most likely break the prop on your first time out too.

I've had that experience with one of the two ARF models I fly. The other one, a powered glider, has a folding propeller, so that propeller hasn't broken yet. The rest of the plane, yes, but not the propeller.

Any opinions on the flexible (I assume rubber) prop connector the the FliteTest folks discuss in a video? Supposedly it provides some give, reducing the chances of breakage.

Post some pics if you can. They are always welcome.

You can see a bunch of step-by-step pix on my RCGroups build thread: Building a Flite-Test Flyer Airplane from Speed-Build Kit and from Scratch. Also, when I make a flight video, I'll be sure to post a YouTube link to it.

Bill

 

[Gazoo]

I've had that experience with one of the two ARF models I fly. The other one, a powered glider, has a folding propeller, so that propeller hasn't broken yet. The rest of the plane, yes, but not the propeller.

Any opinions on the flexible (I assume rubber) prop connector the the FliteTest folks discuss in a video? Supposedly it provides some give, reducing the chances of breakage.



You can see a bunch of step-by-step pix on my RCGroups build thread: Building a Flite-Test Flyer Airplane from Speed-Build Kit and from Scratch. Also, when I make a flight video, I'll be sure to post a YouTube link to it.

Bill

I use the "prop savers" on motors that have a thin, non-threaded shaft. Not only does it keep the prop from breaking (most of the time) but it also saves the shaft from getting bent.

On the threaded shaft motors, I just hope for the best. I haven't seen any prop savers that would work on a threaded shaft.

I notice that when making abrupt changes in attitude, it may jump off the hub of the saver. Or if using a high power setup.

Here is a pic of my flyer with the prop saver. It uses a "blue wonder" motor (24g motor) and the shaft is kind of bendy.

EDIT: The prop saver is a hub that uses two screws to friction fit onto a shaft (set screw style). Then the prop is attached using a rubber o-ring around the set screws to hold it on. I get them from http://www.headsuphobby.com/Prop-Savers_c_236.html

You need to make sure that the hole in the prop matches the size of the hub. You can flip it the other way as it has multiple sizes on either side.

 

[BSquared18]

I haven't seen any prop savers that would work on a threaded shaft.

The one for the Flyer is threaded. But I'll keep your info in mind.

Bill