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RV-4 Sink Rates?

TheFrisco

Member
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
 
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.
 
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
 
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
 
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