13x6.5 vs 14x6 prop - WattFlyer RC Electric Flight Forums - Discuss radio control eflight

General Electric Discussions Talk about topics related to e-powered RC flying

13x6.5 vs 14x6 prop

Old 09-15-2015, 01:14 PM
  #1  
Flysohigh
electrified
Thread Starter
 
Flysohigh's Avatar
 
Join Date: Feb 2011
Location: Miami
Posts: 257
Default 13x6.5 vs 14x6 prop

I want a bit more thrust for takeoff and was thinking on going to a 14x6 prop from my 13x6.5. What can i notice between the change in amps and performance? This is for a suoer cub 25e eflite.
Flysohigh is offline  
Old 09-15-2015, 05:05 PM
  #2  
fhhuber
Super Contributor
 
fhhuber's Avatar
 
Join Date: Mar 2013
Posts: 4,786
Default

The 14XD6 will draw more amps. You'll need to do a wattmeter test to verify that its not excessive. This could be a problem for you because you already have an issue with an overheating ESC.

It would give more disc area and therefore more static thrust.
fhhuber is offline  
Old 09-15-2015, 05:11 PM
  #3  
Flysohigh
electrified
Thread Starter
 
Flysohigh's Avatar
 
Join Date: Feb 2011
Location: Miami
Posts: 257
Default

Actually i was able to get it in the motorbox as you mentioned and i figured going up on diameter and down .5 pitch will give me more thrust which is what i want for takeoff and slower landings
Flysohigh is offline  
Old 09-15-2015, 05:16 PM
  #4  
fhhuber
Super Contributor
 
fhhuber's Avatar
 
Join Date: Mar 2013
Posts: 4,786
Default

You would need to trade appx 1.5 inch pitch for 1 inch dia at that size prop to keep the same load. 0.5 is nowhere near the correct trade if trying to keep the same load.

You may have improved the cooling issue of the ESC some, but without baffles to control and direct the air movement over the ESC its not going to be a large enough change to deal with added heat load.
fhhuber is offline  
Old 09-15-2015, 05:36 PM
  #5  
Flysohigh
electrified
Thread Starter
 
Flysohigh's Avatar
 
Join Date: Feb 2011
Location: Miami
Posts: 257
Default

So for my case what would you recommend if i want to use a 14 in prop?
Flysohigh is offline  
Old 09-15-2015, 09:10 PM
  #6  
fhhuber
Super Contributor
 
fhhuber's Avatar
 
Join Date: Mar 2013
Posts: 4,786
Default

Without testing the plane and without using a wattmetr.... I can't make a recommendation.
fhhuber is offline  
Old 09-16-2015, 10:59 PM
  #7  
JetPlaneFlyer
Super Contributor
 
JetPlaneFlyer's Avatar
 
Join Date: Mar 2009
Location: Aberdeen, Scotland
Posts: 6,121
Default

As a rule of thumb pitch much less than half of diameter gets very inefficient. You are already at that limit with your 13x6.5 so dropping much more pitch and increasing diameter is likely to yield poor results except at very low speeds.

A plane that lands 'hot' usually does so because it's got high wing loading and if you try to slow it down it stalls. Changing a prop wont help with that.
JetPlaneFlyer is offline  
Old 09-16-2015, 11:22 PM
  #8  
fhhuber
Super Contributor
 
fhhuber's Avatar
 
Join Date: Mar 2013
Posts: 4,786
Default

Well... planes can land hot for all sorts of reasons.

CG too far forward and you run out of elevator if you don't keep the airspeed up.

Some designs tend to build speed coming down if you aren't careful. That would be pilot error in how they want the plane to appear as they make the final approach. You should see the bottom of the wing, indicating a slight nose up attitude. If you see the top its diving and accelerating.

Or just being scared of the stall.. from not practicing slow flight and stalls at altitude.

The overweight plane in my avatar pic has a calculated 35 mph "stall" speed. (minimum for sustained level flight.. it can stall at a lot higher) A good approach and it uses less than half the runway vs letting it come in like a bullet.
fhhuber is offline  
Old 09-16-2015, 11:38 PM
  #9  
JetPlaneFlyer
Super Contributor
 
JetPlaneFlyer's Avatar
 
Join Date: Mar 2009
Location: Aberdeen, Scotland
Posts: 6,121
Default

Originally Posted by fhhuber View Post
Well... planes can land hot for all sorts of reasons.
True, but a finer pitch prop is unlikely to 'fix' any of them.
JetPlaneFlyer is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
CHELLIE
Hi-Performance and Sailplanes
2015
05-28-2020 09:50 PM
admin
General Electric Discussions
5477
05-07-2020 05:04 PM
Alabama Flying Dude
Pusher Park Jets
3
05-19-2012 04:13 PM
mclarkson
General Electric Discussions
12
11-26-2011 10:09 PM

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Quick Reply: 13x6.5 vs 14x6 prop


Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.

Page generated in 0.09753 seconds with 15 queries