HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Feb 15, 2013, 11:07 PM
Registered User
Canada, BC, Kelowna
Joined Jun 2006
75 Posts
Discussion
Looking for a 12.5x4 folding prop

Anyone knows who makes a 12.5x4 folding prop?
Looking to install on my 2m Simprop Excel Competition (first series fiberglass fuselage, with built-up wing), using a C3542/06 KV100 // SK3536/05 KV1400 or SK3548/03 KV1100), on 3 / 2 or 5 cells respectively.
My calcs show that this would make interesting combinations ...

I thought there was a CAM one available, but can't seem to find one.
CoolCanuck is offline Find More Posts by CoolCanuck
Last edited by CoolCanuck; Feb 15, 2013 at 11:13 PM.
Reply With Quote
Sign up now
to remove ads between posts
Old Feb 16, 2013, 02:26 AM
Registered User
Canada, BC, Kelowna
Joined Jun 2006
75 Posts
Thanks Rick. Aware of those.
I already have an Aeronaut 12.5x6, hence looking for the 4"pitch.
CoolCanuck is offline Find More Posts by CoolCanuck
Reply With Quote
Old Feb 16, 2013, 05:14 AM
Registered User
WimH's Avatar
Belgium, Flemish Region, Oosterzele
Joined Dec 2001
5,484 Posts
The white Aeronaut 12* 7 folder has a real life pitch much closer to 5 than 7 and may be exactly what you're after. You could use a twisted aeronaut yoke to fine-tune it even further , here's a list with measured values for the black/carbon props...(in cm ....)
http://www.aero-naut.de/fileadmin/do...eichswerte.xls
WimH is offline Find More Posts by WimH
RCG Plus Member
Latest blog entry: That elusive thermal...
Reply With Quote
Old Feb 16, 2013, 03:10 PM
Registered User
Canada, BC, Kelowna
Joined Jun 2006
75 Posts
Thanks Wim. I'll have to investigate this a bit further and educate myself. Never considered offset yokes before.
CoolCanuck is offline Find More Posts by CoolCanuck
Reply With Quote
Old Feb 16, 2013, 05:33 PM
Registered User
sneu's Avatar
United States, CA, San Diego
Joined Dec 1999
7,358 Posts
There is a good reason why they don't make many props like a 12.5x4---they are best suited for applying epoxy than to spinning on the nose of your plane. Anything below a .5 pitch-diameter ratio is not good for things that fly. Props like that will give lots of static thrust but once the plane is moving things go bad. Better to get a smaller diameter prop with more pitch. As a general rule you want a PD of .75 or more.

Steve Neu


Steve
sneu is offline Find More Posts by sneu
Reply With Quote
Old Feb 16, 2013, 10:14 PM
Registered User
vil64's Avatar
Joined Nov 2012
196 Posts
Hey guys, this is what I'm looking for. I've got 2m moldie and would like to use Neu 1110/1y/6.7 motor. Can somebody tell me what would be the smallest folder you can run on this with high pitch for speed.
vil64 is offline Find More Posts by vil64
Reply With Quote
Old Feb 17, 2013, 01:57 AM
Registered User
Romania, Dolj, Craiova
Joined Sep 2007
15,208 Posts
Quote:
Originally Posted by sneu View Post
There is a good reason why they don't make many props like a 12.5x4---they are best suited for applying epoxy than to spinning on the nose of your plane. Anything below a .5 pitch-diameter ratio is not good for things that fly. Props like that will give lots of static thrust but once the plane is moving things go bad. Better to get a smaller diameter prop with more pitch. As a general rule you want a PD of .75 or more.

Steve Neu


Steve
Not valid for all cases.
In multicopters the lowest PD possible is the most sought. 12x3.8 is the most obvious example that comes now, but also 17x5 are available.
Yes, this application field means lots of static thrust, and (apparently) zero speed.
But I think it is valid for gliders propulsion too. I climb better with a 13x5 than with a 12x6.5, same MVVS 960kv motor.
renatoa is offline Find More Posts by renatoa
Reply With Quote
Old Feb 17, 2013, 01:29 PM
Registered User
sneu's Avatar
United States, CA, San Diego
Joined Dec 1999
7,358 Posts
Quote:
Originally Posted by renatoa View Post
Not valid for all cases.
In multicopters the lowest PD possible is the most sought. 12x3.8 is the most obvious example that comes now, but also 17x5 are available.
Yes, this application field means lots of static thrust, and (apparently) zero speed.
But I think it is valid for gliders propulsion too. I climb better with a 13x5 than with a 12x6.5, same MVVS 960kv motor.
A PD prop is like a plane stuck in 1st gear--lots of pull at the start but is quickly hits the wall and stops accelerating. The one place low PD makes sense is for static operation--like the quad copters but gliders are better with higher PD props.

Steve Neu
sneu is offline Find More Posts by sneu
Reply With Quote
Old Feb 17, 2013, 01:30 PM
Registered User
sneu's Avatar
United States, CA, San Diego
Joined Dec 1999
7,358 Posts
Quote:
Originally Posted by vil64 View Post
Hey guys, this is what I'm looking for. I've got 2m moldie and would like to use Neu 1110/1y/6.7 motor. Can somebody tell me what would be the smallest folder you can run on this with high pitch for speed.
How many cells?
sneu is offline Find More Posts by sneu
Reply With Quote
Old Feb 18, 2013, 04:09 AM
Registered User
vil64's Avatar
Joined Nov 2012
196 Posts
Planning 3cell 2200mAh
vil64 is offline Find More Posts by vil64
Reply With Quote
Old Feb 18, 2013, 08:54 AM
Registered User
sneu's Avatar
United States, CA, San Diego
Joined Dec 1999
7,358 Posts
Quote:
Originally Posted by vil64 View Post
Planning 3cell 2200mAh
There are F5D pylon props that are 11x22 that would give you around 140mph prop pitch speed. http://www.neumotors.com/store/page11/index.html

If those are over the top then I would be looking at a 12.5x13 of 15x16 from SUSA http://www.soaringusa.com/Props/?page=11

Steve Neu
sneu is offline Find More Posts by sneu
Reply With Quote
Old Feb 19, 2013, 04:43 AM
Registered User
vil64's Avatar
Joined Nov 2012
196 Posts
Thanks Steve, that's the info I was looking for.
vil64 is offline Find More Posts by vil64
Reply With Quote
Old Mar 11, 2013, 06:31 AM
Registered User
vil64's Avatar
Joined Nov 2012
196 Posts
Hi Steve, I have just changed my mind and plan to use Neu 1105/2.4y/4.4:1 instead of 1110/1y/6.7. Still, I will use 2200mAh 3S. Could you please let me know what could be the smallest folding prop I can use for speed. This is going to a 2m Spirit E glider/hotliner.
vil64 is offline Find More Posts by vil64
Reply With Quote
Old Mar 11, 2013, 10:41 PM
Balsa addiction since age 3
ScottSails's Avatar
Upstate NY
Joined May 2005
1,260 Posts
Quote:
Originally Posted by sneu View Post
A PD prop is like a plane stuck in 1st gear--lots of pull at the start but is quickly hits the wall and stops accelerating. The one place low PD makes sense is for static operation--like the quad copters but gliders are better with higher PD props.

Steve Neu
Awesome analogy.... I think this is a great way to describe it.
ScottSails is offline Find More Posts by ScottSails
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Question Looking for 1mm shaft folding prop adapter rdeis Scratchbuilt Indoor and Micro Models 7 Jan 24, 2013 10:41 PM
Wanted I'm looking for a folding prop spinner mikez64 Aircraft - General - Miscellaneous (FS/W) 2 Jan 16, 2013 09:23 AM
Question Looking For A 4.5x4.5 Prop Bookstar75 Power Systems 5 Jan 17, 2010 10:20 PM
Question Looking For a 5x4 speed prop Bookstar75 Power Systems 6 Mar 14, 2009 12:15 AM
replacement prop for potensky folding 9.5x4.7 tduro Power Systems 1 Nov 14, 2005 08:48 PM