axlr8r

axlr8r

Well Known Member
First ride in RV 8 today. Power off stall, st. ahead and clean at 80 mph. Seems too fast. I've heard that 68 mph. is closer to correct speed in this config. Final approach w/ full flaps did not seem fast at 85 mph. Could this possibly be a calibration problem with the A/S indicator. or is 80 mph about right.
Any help appreciated for this forum newbie. I did search FAQ's w/ no luck.

Thanks

Steve
 
Are the upper gear leg intersection fairings installed yet? If not, Randy Lervold reported a noticeable reduction in stall speed when he installed his.

It is also quite possible that you have airspeed accuracy problems. Do the following checks:
  1. conduct leak checks on pitot and static systems,
  2. check for ASI instrument error. You can either take the ASI to a shop that has a pitot static system tester, and have them check the ASI accuracy, or do it yourself with a water manometer. If you have an instrument shop do it, have them actually record the error at various speeds, rather than simply tell you that it is in spec. You'll want to know the actual errors later.
  3. conduct flight tests to measure airspeed system error. You can't do these tests at the stall speed, but you can measure the errors from about 1.1 times the stall speed up to the max speed that you can achieve in level flight.
Lots more info on my web page Determining Static System Error.

As far as the "correct" approach speed for your aircraft goes, be careful using recommended speeds you get from someone else. The ideal IAS will vary, depending on airspeed system errors, type of prop, flap angle, approach technique and pilot skill. The IAS that is perfect for one pilot in his RV may be quite wrong for another pilot in his own RV.
 
Kevin's advice is golden!

I'd also ask which static ports you're using, and where they are located. I have had a ten knot increase in indicated airspeed with a disconnected static line behind the panel BTW, so a static leak is not unreasonable at all.

Paul
 
Steve, what Kevin and Paul said. For comparison here is a link to my web site with the stall data I collected that Kevin referenced.

This data was collected with an ASI that was known accurate, checked against GPS ground speed and other aircraft. Your static system and even the shape of the static ports will have a significant impact. for example if your static ports and truly flush with the side of the plane they will be inaccurate, lots of info in the archives on this.
 
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Kevin, Paul and Randy,
You guys are the greatest. VAF can now add my name to the long list of people that rave about the assistance available on these forums.
I checked Van's website an discovered that the stall speed should be about 51mph plus any increase in load or flap position. My perception of the speed during the stall and on aph. did not seem to be as indicated on the ASI (80 mph - calm day).
This was my first RV experience. After this ride and, months of research, I'm totally convinced that this is the airplane for me. So...I want to make sure that my decision to buy this particular aircraft is an informed one.
Thanks to you guys I'm off to a good start. Now off to the superior website for more problem solving.

Thanks again

Steve
 
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