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 07-28-2021, 09:57 AM
TheFrisco TheFrisco is offline
 
Join Date: Mar 2020
Location: Santa Cruz, CA
Posts: 31
Default RV-4 Sink Rates?

Setting up my new Dynon SkyView HDX and for the glide circle it asks for a sink rate ... What are others using for their sink rates?

My Google searches gave me numbers from 600-1000 fpm ... quite the spread LOL
Reply With Quote
  #2  
Old 07-28-2021, 11:12 AM
YellerDaisy's Avatar
YellerDaisy YellerDaisy is offline
 
Join Date: May 2012
Location: Mountain Southwest
Posts: 213
Default

In my RV-4, normal base/final is full flaps, idle (900 rpm), and 55 kts IAS. At 1350 lbs and 6,500' DA, RoD is ~700 fpm.
__________________
JD
RV-4 - 160HP O-320 - Sensenich GA
RV-3B - O-320 - "Daisy" (sold)
http://jdfinley.com
Videos
Reply With Quote
  #3  
Old 07-28-2021, 03:44 PM
TheFrisco TheFrisco is offline
 
Join Date: Mar 2020
Location: Santa Cruz, CA
Posts: 31
Default

Thanks much appreciated!!!
Reply With Quote
  #4  
Old 07-29-2021, 03:14 PM
Christopher Murphy Christopher Murphy is offline
 
Join Date: Feb 2007
Location: colorado
Posts: 933
Default 55kts?

My -4 stalls at 54kts.
Cm
__________________
RV-4 "Mr. Twister"
Pitts S1S "Mexican Red" sold and missed
Mr. Twister Airshows
Rocky Mountain Renegades
the mission... have fun.
Reply With Quote
  #5  
Old 07-29-2021, 03:38 PM
YellerDaisy's Avatar
YellerDaisy YellerDaisy is offline
 
Join Date: May 2012
Location: Mountain Southwest
Posts: 213
Default

I'm guessing that (55kts?) is a question for me.

Mine has a VS0 of 42 kts IAS at 1350 lbs and 7000' DA. I wouldn't claim that my airspeed indicator is perfect at that low airspeed but it seems to be reasonably accurate.

https://youtu.be/prg8jEWa8SI
__________________
JD
RV-4 - 160HP O-320 - Sensenich GA
RV-3B - O-320 - "Daisy" (sold)
http://jdfinley.com
Videos
Reply With Quote
  #6  
Old 08-04-2021, 12:40 AM
n82rb's Avatar
n82rb n82rb is offline
 
Join Date: Jan 2007
Location: fort myers fl
Posts: 1,131
Default

the only real way to get the real numbers is to test it. climb pull it to idle, nail speed and when stabilized and passing an altitude start timing and hold speed. note altitude at 1 or 2 minutes in. climb back up and repeat at different speed. plug it in a spread sheet and calculate rates of decent for all timings.
every plane is going to different.
also, remember a windmilling prop will have different numbers than a stopped prop so the windmilling prop should give you a bit more safety margin with the circle.
i have not done the number for C/S at both fine and coarse pitch, but they should also give different numbers



bob burns
RV-4 N82RB
Reply With Quote
  #7  
Old 08-07-2021, 03:14 PM
Whitman Whitman is offline
 
Join Date: Oct 2010
Location: Allentown PA
Posts: 280
Default

Quote:
Originally Posted by Christopher Murphy View Post
My -4 stalls at 54kts.
Cm

You sure it isnít 54 MPH? My -4 stalls at 43 knots full flaps and 47 knots clean
__________________
RV-4
IG: flywithwhit

"Poise under pressure is the single most valuable thing you can have as a pilot. Make mistakes, take corrective action as quickly and calmly as possible and press on."
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 10:29 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.