Will this propeller be a problem?
 

Hi All,

This has probably been asked before, but I can't seem to find it.
So I mistakenly bought a 9 x 6 "E" prop (packaging says "thin electric", manufactured by APC), instead of 9 x 6 "SF" (slow flyer).
Will that be OK for my SuperTigre 400 motor?
It is clearly heavier and seems to be much stiffer (blades barely bend), but it's the same diameter and pitch, so maybe it's OK???

Thanks!

They are very different as you point out. The APCe will probably draw less current but is a bit less efficient at the lower RPM. They are also heavy for use in smaller planes. Do you have a watt meter so you can measure the current?

BTW - I don't use either the APCe or SF type propellers on motors of that size however.

I am really fond of the GWS "HD" (also called Direct Drive) type props for those power levels. They are very efficient!

They make a 9x5 and 9x7.5 that might work well for you. The best thing is I get them from here:

http://www.gwsprops.com/ for cheap and cheap fast shipping.

This is the page for the HD series:
http://www.gwsprops.com/direct_drive.htm

Mike

The plane is a NexStar mini. I think the plane won't be overweight and I'll balance it, but I'm just not sure about the motor itself (spinning more weight might be too much for it???).
I have a multimeter. At what points do I put the positive and negative leads? Should I be measuring at full throttle? Also, there is already current draw from the receiver, so I guess I'd be interested in the diff, right?

No the prop would be OK to try.

Multimeters generally have very limited current measuring ability (if any). You will need one that does DC amperage to about 30 amps or so.

I recommend a dedicated, in line, watt meter to measure current. Here are some examples:
http://www3.towerhobbies.com/cgi-bin...&I=LXBHDT&P=ML
http://www3.towerhobbies.com/cgi-bin...&I=LXLMV0&P=ML
http://www3.towerhobbies.com/cgi-bin...&I=LX3605&P=ML

If you are OK with Hobby King - this one is a budget model - not sure how it works. The others (above) are well used in the game.

http://www.hobbyking.com/hobbyking/s..._Analyzer.html

Once you get to really high power systems over 80 or so amps you need a clamp meter but I don't suspect that will be a big issue for you for a while.

Mike

Mike,

You are a fountain of useful tips.
Thanks!

If you like to do a lot of verticle, or hanging off of the prop, then a gws or even the sf props are not the best choice. I have noticed quite a bit of improvement in verticle performance on my slow stick, and alpha by using a apc "e" rated prop. I use the gws ones when the hoby shop is out of stock, or when I'm flying a plane with a 3mm or smaller motor shaft. An apc prop will bend the 3mm shaft, on virtually any impact or prop strike.

Well, the motor shaft is definitely no more than 3mm, so it's good you told me about that! I may just wait till the SF ones I ordered come in, if I can hold out - I'll be abroad for 2 weeks by the time they arrive :mad:, so I really want to fly before I leave (if the weather permits).

Order a motor shaft or two, and throw it on. Then if you do bend the shaft, you'll have another one on the way. You could also try to use a prop saver. They can be made with a servo horn dilled out to fit over the shaft, then stick the nut to it, then cut the shaft off before the end of the prop.use rubber bands, or o-rings to hold the prop on.

This is a lot of the reason I like my heads up 450 class motors. They have a 4mm shaft plus they have prop adaptar included. I have bent mine on really had nose ins, but I am still running the origional shaft on my first motor. I probably have well over 200 flights on it, most with a thicker prop, like a apc "e".

I think that the 9x6 APC E is heavier than that 52g motor might like... a 9x6 APC SF would be a better choice, though it might put you close to the motor's limit for amp draw (rated for 13A: 9x6 APC SF on 3s gets you this: 12.70A, 136W, 6240rpm, 35.5mph, 621g, 21.87oz, 4.57g/W).

Take a look at what a 9x5 GWS HD gets you for waaay less current/watts.. yet only 1.3oz less thrust: 7.70A, 83W, 7770rpm, 36.8mph, 584g, 20.56oz, 7.04g/W