Ef1 Pylon props - RC Groups
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Oct 17, 2017, 11:31 PM
Hilson87
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Discussion

Ef1 Pylon props


Where is the best source of pylon prop for EF1 class pylon planes? I'm working on a fun project with the great planes proud bird and need a prop that going to be able to handle 2000 watts give or take. The only props I know of that can handle this kind of power is a glow apc prop. I mostly fly precision/freestyle stuff so pylon stuff isn't all that familiar to me. I'm looking for the highest performance airfoil and stiffness possible. Would love to find some trick carbon fiber ones. Anyone that can point me in the right direction I would appreciate it. Looking for 8" diameter but not sure of which pitch is going to provide the greatest top speed. This is purely a just for fun project so there are no rules or stipulations, I just want all out wide open speed.

Going to either fly it on either 5s or 6s but still running numbers on power system choices I'm going to run.

Blake H.
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Oct 18, 2017, 10:40 AM
And You're Not
APC makes (or used to make) some carbon fiber Q40 props in ~8" diameter.
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Oct 18, 2017, 01:14 PM
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The EF-1 rules specify one prop, which is the APC 8x8. The hub is marked C-2, so it is designed for higher RPM, and typically turns around 16,000. This motor/prop combination results in massive torque, and it's not uncommon to see airplanes try to torque roll on take off. If you go to a larger motor, and Q-40 carbon props expect to see evil tendencies on take off. You'll probably have trouble squeezing a larger motor in the cowl, and you'll want to reinforce the firewall. Finally good luck squeezing a 5s or a 6s in the battery compartment which will probably result in a very nose heavy airplane.
Oct 18, 2017, 02:29 PM
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The one-and-only prop legal for EF1 is that APC 8x8, so not sure what you mean by "EF1 class."

Maybe this will assist you with your calculations:
On an EF1 motor we go about 630W, maybe about 15,000rpm in-flight. Average voltage (per cell) is about 3.55 V/cell (all of the preceding during about a 75 second full-throttle flight).

I don't think it's the Watts you would be concerned about with the propeller - it's the rpm, right.

APC limits the Thin E series of props to 145,000 / prop diameter. For the 8" EF1 prop that's about 18,000rpm - not much more than we are doing with these props now.

A few of us here have contemplated trying a Proud Bird on 5S just to see. I think there was some chatter of it over here and I believe one person somewhere therein did it:

https://www.rcgroups.com/forums/show...an-EF1-%28-%29

I'd be very concerned about flying a Proud Bird on much more than an EF1 motor (1200kV) on 5S with the 8x8 prop (whatever rpm and power that produces). It's not over-designed or intended for much more than that. Of course, possibly you have already planned to reinforce. Then cool!

I guess you'll want a pretty high kV motor like 2500kV is just a guess off the top of my head. Try a few of the e-calculators out there.

Sounds interesting!

Tim
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Oct 18, 2017, 04:33 PM
Hilson87
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Thank you everyone for the guidance. I will likely be using 6s and do plan on doing airframe modifications and reinforcements. This is a “just for fun” thing in which I never plan to actually race. It’s going to be a fun weekend sport plane that will blow by some edf’s lol that’s about it. A little strategic carbon here and there and some airframe mods to cram a 6s battery in there is certainly doable if you arent afraid to cut some wood and use a little carbon fiber. I don’t like to do cookie cutter projects and tend to enjoy going off the beaten path to try new things and do what may be considered “herocy” lol . I will contact APC to see what size carbon pylon props they make. So being that this is just for fun and I’m looking for flat out Speed there are zero restrictions on anything and the only limiting factor is my imagination. For an airframe that’s only $150 it makes the project that much more fun being such a small investment in the airframe.

Blake
Oct 18, 2017, 04:47 PM
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You can just log onto the APC web site and see their offerings. Here's the page for their carbon fiber electric-only propellers. They are not carbon fiber in the way that you may think. They are still injection-molded, but with cf strands in with the resin:

https://www.apcprop.com/shop/?produc...-electric-only

In one of the classes of .40 glow-powered pylon racing we use "carbon fiber" props in the 7.4" diameter (they turn around 27,000rpm in the air):

https://www.apcprop.com/shop/?produc...2Cpylon-racing


Tim
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Oct 18, 2017, 05:55 PM
And You're Not
I don't see the one I used to run, 7.4 x 8.25 I think it was - I ran it on a .46 VRDF Got the props and the pipe from Performance Specialties years ago, ol' Dave still hangs around here these days flying in a more relaxed mode.

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Oct 18, 2017, 10:58 PM
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Jeffery. Good luck on your project. I'm more inclined to agree with Tim. EF-1's do about 115mph. They aren't designed for the speeds you are contemplating. In addition as Tim mentioned the Q40 props will hold up at 27,000rpm's. What he didn't mention is that those Q40's do almost 200mph. Is that what you want a $150.00 Proud Bird to do? You can purchase off the shelf FAI electric pylon racers, motors, and batteries that will do over 200mph, and are designed to stand up under those speeds. That's what I'd do if I wanted to impress my club members. Then you could try out for the next F5D team.
Oct 18, 2017, 11:51 PM
And You're Not
That project was from years ago, I was just reminiscing about what APC CF props I'd used.
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Oct 19, 2017, 09:28 AM
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Quote:
Originally Posted by Greg Doe
Jeffery. Good luck on your project. I'm more inclined to agree with Tim. EF-1's do about 115mph. They aren't designed for the speeds you are contemplating. In addition as Tim mentioned the Q40 props will hold up at 27,000rpm's. What he didn't mention is that those Q40's do almost 200mph. Is that what you want a $150.00 Proud Bird to do? You can purchase off the shelf FAI electric pylon racers, motors, and batteries that will do over 200mph, and are designed to stand up under those speeds. That's what I'd do if I wanted to impress my club members. Then you could try out for the next F5D team.
Hi Greg! Thanks for carting us around at the Champ race!

About 200mph sport/F5D planes...go here!

https://www.rcgroups.com/forums/show...ovable-nose%29

https://www.rcgroups.com/forums/show...er-sport-plane

Tim
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Oct 19, 2017, 11:22 AM
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Tim, You are welcome. Thanks for supplying the links. Maybe it will inspire Jeffery to give F5D a try?
Oct 19, 2017, 12:13 PM
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Oct 19, 2017, 01:22 PM
Hilson87
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Gorgeous F5D planes no doubt! But where’s the fun in something engineered to already go fast? Rather let’s make something that not suppose to go fast go even FASTER!!!

My Analogy for this project:

I could go buy a Porsche’s GT3 and go set records at the ring or I could buy a beat up Volkswagen and completely re-engineer it to be just slightly slower than that GT3.

It’s about what you find the fun in, I myself like the journey as I find reaching the goal at the end to be that much more rewarding and fun!
Last edited by Hilson87; Oct 19, 2017 at 01:27 PM.
Oct 19, 2017, 02:47 PM
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Hilson87. I agree 100%. Do what ever brings you the most satisfaction. We were looking at your project through our "eyes". Let us know how it turns out. By the way my apologies to Jeffery. My bad for confusing you with Hilson. It's caused by birthday cake. Too many of them!
Oct 19, 2017, 03:00 PM
Hilson87
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Quote:
Originally Posted by Greg Doe
Hilson87. I agree 100%. Do what ever brings you the most satisfaction. We were looking at your project through our "eyes". Let us know how it turns out. By the way my apologies to Jeffery. My bad for confusing you with Hilson. It's caused by birthday cake. Too many of them!
I really appreciate the links to the planes! I will likely purchase one eventually just to have one for a once in a blue moon speed fix! They look like works of art! And I certainly appreciate all the help and feedback on the project! You guys certainly know much more about getting speed out of these little pylon planes than I. I’m more F3A/3D kind of guy but I find myself wanting to try new things every once in a while. Which now is something for speeeeeeed!


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