VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.

  #1  
Old 01-28-2020, 03:30 PM
WingnutWick's Avatar
WingnutWick WingnutWick is offline
 
Join Date: Jun 2013
Location: Fresno, CA (KFCH)
Posts: 269
Default Pushing and pulling via the prop.

Hello all,

Just getting an idea on if it's bad or not to gently push/pull the airplane by the root of the prop close to the spinner to move it around. Airplane in question is an RV-6A with O-320 H2AD fixed catto prop.

Thank you!

Cheers
__________________
-Wingnut
F-18E/F, Mk.58, CF-5
Own: RV-8 & RV-10
Reply With Quote
  #2  
Old 01-28-2020, 03:37 PM
ColoradoSolar ColoradoSolar is offline
 
Join Date: Dec 2018
Location: Westcliffe, Colorado
Posts: 142
Default

I push and pull my RV-6A by the prop and was told to do so by my mechanic. Think about it, the prop is pulling the plane through the air so there is much more load on it when flying than you could put on it on the ground. Now I do like you said and push/pull near the hub not way out at the tip, even though I doubt even that would cause any issues.
__________________
Eric Vickery

RV-6A Tip-Up Bought Flying
Reply With Quote
  #3  
Old 01-28-2020, 03:45 PM
skylor's Avatar
skylor skylor is offline
 
Join Date: Aug 2009
Location: Southern California
Posts: 1,022
Default

Quote:
Originally Posted by ColoradoSolar View Post
I push and pull my RV-6A by the prop and was told to do so by my mechanic. Think about it, the prop is pulling the plane through the air so there is much more load on it when flying than you could put on it on the ground. Now I do like you said and push/pull near the hub not way out at the tip, even though I doubt even that would cause any issues.
For a Hartzell CS prop, Hartzell recommends against this. The reason given is that supposedly without the centrifugal force of the prop rotation pulling the blades into their bearings, the bearings can be damaged from pulling on the blades.

Frankly, I find it hard to believe that gentle pull or push at the blade root could be any harder on the bearings than some of the occasional "violence" of engine start-up and shut-down when the prop doesn't have much rotation velocity...

Skylor
Reply With Quote
  #4  
Old 01-28-2020, 03:49 PM
ColoradoSolar ColoradoSolar is offline
 
Join Date: Dec 2018
Location: Westcliffe, Colorado
Posts: 142
Default

Ah, I guess I left out a bit of info. I have a fp prop on my plane. I could see where it might be slightly different with a cs prop but with how light our planes are I still don't see how that could cause a problem.
__________________
Eric Vickery

RV-6A Tip-Up Bought Flying
Reply With Quote
  #5  
Old 01-28-2020, 03:54 PM
AlexPeterson's Avatar
AlexPeterson AlexPeterson is offline
 
Join Date: Sep 2005
Location: Ottertail, MN
Posts: 2,459
Default

Quote:
Originally Posted by skylor View Post
For a Hartzell CS prop, Hartzell recommends against this. The reason given is that supposedly without the centrifugal force of the prop rotation pulling the blades into their bearings, the bearings can be damaged from pulling on the blades.

Frankly, I find it hard to believe that gentle pull or push at the blade root could be any harder on the bearings than some of the occasional "violence" of engine start-up and shut-down when the prop doesn't have much rotation velocity...

Skylor
Approximate percent of people who use prop to pull their Hartzell (and others) equipped RV's is 100%
__________________
Alex Peterson
RV6A N66AP 1750+ hours
KADC, Wadena, MN
Reply With Quote
  #6  
Old 01-28-2020, 04:00 PM
burgundyja's Avatar
burgundyja burgundyja is offline
 
Join Date: Nov 2006
Location: maple grove,mn
Posts: 247
Default why do it?

There is a thrust bearing in the engine but on the ground it has no oil pressure.
If you can push or pull without turning the prop it's probably ok but if it turns as you are pulling it could damage the bearing. So why not just push on the cowl and pull with a tow bar?
__________________
Mike Johnson
8A N484M
Reply With Quote
  #7  
Old 01-28-2020, 04:24 PM
bobnoffs bobnoffs is offline
 
Join Date: Jul 2012
Location: n. wi
Posts: 862
Default

sorry, i gotta disagree. it is just totally illogical that my little 5 fingers pulling at the hub of the prop on that bearing is gonna damage it while it lugs around that airframe at 200 mph being pulled by 200 hp. oil pressure or no oil pressure. i would be way more cautious of damaging my cowling.
.
__________________
Bob Noffs
n. wi.
dakota hawk/jab 3300 built and flying. sold 6/18.getting serious about the 12. in the hangar now as of 10/15/19
RV-12 kit as of 9/13
Reply With Quote
  #8  
Old 01-28-2020, 04:56 PM
pa38112 pa38112 is offline
 
Join Date: Mar 2008
Location: Clarksboro, NJ
Posts: 1,003
Default

Post 5 +1 This issue is that if the prop mfg.s OK pushing and pulling on the prop then people will push and pull on the tips and asymmetrically. If you push and pull at the hub and do it evenly on both sides, you are fine.
__________________
http://aprs.fi/N153MC
2004 RV6A Flying
2002 RV6A Flying
1978 PA38-112
Reply With Quote
  #9  
Old 01-28-2020, 06:39 PM
Boyd Birchler Boyd Birchler is offline
 
Join Date: Sep 2014
Location: IN
Posts: 254
Default

Wife and I have owned 20+ personal use airplanes over the past 47 years. We have pulled or pushed on the props, near the hub, on all of them.

I have had many of the engines on our planes apart (I'm an A&P/IA), and the engines on other's planes apart also,and have so far, never witnessed damage caused by this practice.
Reply With Quote
  #10  
Old 01-28-2020, 08:59 PM
VIN2020 VIN2020 is offline
 
Join Date: Feb 2015
Location: Fort Worth
Posts: 31
Default

Quote:
Originally Posted by bobnoffs View Post
sorry, i gotta disagree. it is just totally illogical that my little 5 fingers pulling at the hub of the prop on that bearing is gonna damage it while it lugs around that airframe at 200 mph being pulled by 200 hp. oil pressure or no oil pressure. i would be way more cautious of damaging my cowling.
.
Spot on given that heat is what degrades bearings and their lubrication. Turning the prop by hand will never heat to even close their continuous design run temperature.
__________________
Blake Graham N801RH
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 01:07 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.