HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Aug 24, 2006, 10:34 AM
Registered User
taekwondo's Avatar
USA, FL, Orlando
Joined May 2003
7,977 Posts
Discussion
Prop issues: APC SF vs. APC C2 Prop

Hello:

I have a question regarding APC SF vs. APC C2 Props. When I first started, i used gws orange props. later on I migrated to apc sf. I broke a 13x6.5 apc prop and was wondering if they were basically interchangeable with the c2 props, or are these for gas planes? Also, what is the difference between sf and E apc props? lastly I have a 11x8 C2 prop vs. the original 13x6.5 apc sf, would this work? What wuold be the difference in thrust/speed? My understanding so far has been essentially that 1 inch in diff is about the same as one pitch, so the 13x6.5 shoud be equivalent to an 11x8.5? Thoughts?
taekwondo is offline Find More Posts by taekwondo
Reply With Quote
Sign up now
to remove ads between posts
Old Aug 24, 2006, 12:20 PM
Old age is not for sissies
Azarr's Avatar
Dayton Intl, Ohio, United States
Joined Jan 2000
7,916 Posts
Quote:
Originally Posted by taekwondo
Hello:

I have a question regarding APC SF vs. APC C2 Props. When I first started, i used gws orange props. later on I migrated to apc sf. I broke a 13x6.5 apc prop and was wondering if they were basically interchangeable with the c2 props, or are these for gas planes? Also, what is the difference between sf and E apc props? lastly I have a 11x8 C2 prop vs. the original 13x6.5 apc sf, would this work? What wuold be the difference in thrust/speed? My understanding so far has been essentially that 1 inch in diff is about the same as one pitch, so the 13x6.5 shoud be equivalent to an 11x8.5? Thoughts?
The C-2 designation on the hub is used internally by APC and does not designate the type of prop (SF, "E", Sport, etc). The Slo Fly props have are thinner, have more of a "paddle" blade shape and are limited in rpm compared to the "E" props. The slow fly props are limited to 65,000 divided by the diameter while the "E" props are limited to 190,000 divided by the diameter.

If both the 13 x 6.5 and 11 x 8 turned the same rpm, the first should have more thrust and the second more speed.

Azarr
www.ecubedrc.com
Azarr is offline Find More Posts by Azarr
Reply With Quote
Old Aug 24, 2006, 02:54 PM
Registered User
taekwondo's Avatar
USA, FL, Orlando
Joined May 2003
7,977 Posts
Azarr:

Thank you for the info. it seems from what you say, the E props can spin faster. I'm still uncertain what the C-2 is for as they have clearly thicker hubs. So do you think if I replace the SF 13 x 6.5 with the C-2 11 x 8 it will be similar? The diameter is responsible for thrust and the pitch for speed? thanks.
taekwondo is offline Find More Posts by taekwondo
Reply With Quote
Old Aug 25, 2006, 05:34 AM
Old age is not for sissies
Azarr's Avatar
Dayton Intl, Ohio, United States
Joined Jan 2000
7,916 Posts
Quote:
Originally Posted by taekwondo
Azarr:

Thank you for the info. it seems from what you say, the E props can spin faster. I'm still uncertain what the C-2 is for as they have clearly thicker hubs. So do you think if I replace the SF 13 x 6.5 with the C-2 11 x 8 it will be similar? The diameter is responsible for thrust and the pitch for speed? thanks.
There is no APC SF 13 X 6.5, the only 13" SF prop APC makes is a 4.7 pitch. The 13 x 6.5 is an "E" series prop.

The "E" props can handle higher rpms than the SF props without coming apart. (the rpm, of course, would depend on the amount of power adsorbed)

As I said before, the hub designation (C-2) is used by APC internally. AFAIK, it has to do with their mold designations and has no bearing on the type of prop, you'll find SF, "E" and Sport props with the C-2 designation.

I think if you replace the 13 x 6.5 with the 11 x 8 that the current draw will be close to the same, the thrust will decrease and the pitch speed will increase. As far as the motor is concerned, the performance would be similar, but in the plane it's a different matter.

The best predictor, of course, since static thrust show us little except for 3D flight, is to put the watt meter on it and then fly.

Azarr
www.ecubedrc.com
Azarr is offline Find More Posts by Azarr
Reply With Quote
Old Aug 25, 2006, 02:11 PM
Registered User
taekwondo's Avatar
USA, FL, Orlando
Joined May 2003
7,977 Posts
Azarr:

Thank you for the clarification again. Since you said:

if you replace the 13 x 6.5 with the 11 x 8 that the current draw will be close to the same, the thrust will decrease and the pitch speed will increase.

Does that imply I will have less thrust, but with more speed? I'm thinking for this electric telemaster 6' I need thrust, not speed. I might be better off getting another prop then. I guess I could just see how it flies, also. Thanks again.
taekwondo is offline Find More Posts by taekwondo
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
APC SF 9x7.5 prop balance/mount issues? sbmon Power Systems 12 Oct 03, 2005 10:50 AM
Question 11 x 3.8 APC SF vs. 11 x 4.7 SF APC? Shortman Power Systems 5 Feb 01, 2004 12:12 PM
APC Prop question - SF vs. E" yesbee1 Power Systems 3 Nov 29, 2003 12:18 PM
APC E prop VS. APC SF Prop?? BrunswickOH Power Systems 22 Oct 23, 2003 11:13 AM
Graupner CAM Slim Prop vs APC slowflyer props Dauntae Power Systems 5 Jul 15, 2001 12:47 AM