VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics


Go Back   VAF Forums > RV Firewall Forward Section > Propellers
Register FAQ Members List Calendar Today's Posts

Reply
 
Thread Tools Search this Thread Display Modes
  #11  
Old 07-02-2015, 11:07 AM
tmbg's Avatar
tmbg tmbg is offline
 
Join Date: Jan 2008
Location: Atlanta, GA
Posts: 240
Default

I haven't actually measured the length yet, but I did have it off the airplane and sitting next to an AD 68x78 prop a couple weeks ago, and they were the same length, so I'll be surprised if it's shortened.

I will measure the length, a friend has a blade protractor so I'm hoping to be able to measure the pitch, and I'm going to try to install a manifold pressure gauge to try to make sense of this!
__________________
Ian
Reply With Quote
  #12  
Old 07-02-2015, 11:14 AM
Mel's Avatar
Mel Mel is offline
 
Join Date: Mar 2005
Location: Dallas area
Posts: 10,768
Default

Don't be too quick to accept or condemn by measuring pitch unless you have another prop from the same manufacturer to compare.
Every prop manufacturer measures pitch a little differently.
__________________
Mel Asberry, DAR since the last century.
EAA Flight Advisor/Tech Counselor, Friend of the RV-1
Recipient of Tony Bingelis Award and Wright Brothers Master Pilot Award
USAF Vet, High School E-LSA Project Mentor.
RV-6 Flying since 1993 (sold)
<rvmel(at)icloud.com>
Reply With Quote
  #13  
Old 07-02-2015, 12:03 PM
riobison riobison is offline
 
Join Date: Jul 2011
Location: Oliver BC & Red Deer Alberta Canada
Posts: 350
Default

Hello Ian,

What is your density altitude, weight and best ROC that you see when your climbing out at with the 2500 RPM?

2700 RPM at 8000 ft DA is pretty much spot on for 75% power and at 190 mph TAS is bang on for Vans numbers.

Tim
Reply With Quote
  #14  
Old 07-02-2015, 01:33 PM
tmbg's Avatar
tmbg tmbg is offline
 
Join Date: Jan 2008
Location: Atlanta, GA
Posts: 240
Default

Quote:
Originally Posted by Mel View Post
Don't be too quick to accept or condemn by measuring pitch unless you have another prop from the same manufacturer to compare.
Every prop manufacturer measures pitch a little differently.
I'm more looking for gross deviations in pitch... posts like this make me think there has to be something drastically off somewhere:

Quote:
Daver
a couple of data points
I know the following examples are not RV4s but they might give you some additional insight.

My -9A 150 HP 68x72 Sterba prop gets about 2200 static and about 2450 in cruise but I don't have the wheel pants on yet. I'm thinking I'll pick up some cruise RPM with those installed.
a 300rpm difference in static rpm with ostensibly the same engine and prop... obviously density altitude is a factor there, but I can't imagine it being THAT much of a factor!
__________________
Ian
Reply With Quote
  #15  
Old 07-02-2015, 06:05 PM
Kent Ashton Kent Ashton is offline
 
Join Date: May 2010
Location: Concord, NC
Posts: 116
Default

Quote:
Originally Posted by tmbg View Post
a 300rpm difference in static rpm with ostensibly the same engine and prop
You could get a difference in static if the airplanes were headed differently into the wind, or the surfaces winds were stronger or lighter or the engines were leaned differently.
Reply With Quote
Reply



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 05:48 AM.


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.