I am happy...

[kentb]

I finally have all the fairings on and got a good day to do some flight testing up high.

Here is what I got testing performance on my RV9A this last week-end. I have a BMA Lite, BMA Sport , and an AI. Here is the data that I gathered:

Data gathered at 8500 ft (uncalibrated alt) 2550 rpm oat 33 degrees, map 22.1, 100 degrees ROP, ff 10.1 gph.

Lite IA Lite TAS Sport IA Sport TAS AI GPS track GPS GS
140 143 147 351 168
141 158 143 161 147 85 163
141 156 142 159 144 186 162
142 158 143 160 146 275 167

This computes to 165 kts or 189.5 mph TAS. So I figure that my Sport is 5 kts low and that the Lite is 7 kts slow. This is right on Van's number.

I still will be needing to do more testing a different power settings.

Kent

 

[Larry Brons]

Nice, Kent!
Now let's finish mine!

 

[Kevin Horton]

Kent,

Are the two EFIS systems plumbed to the same static, pitot and OAT sources, or does each have its own? I'm wondering whether the differences between the two EFIS systems are simply due to their instrument errors, or whether they have different input data.

Which static ports do you have? Looking at your data, I think there is a good chance you have flush mounted static ports. Any chance there is a static system or pitot system leak?

Where is the OAT probe(s)? Every 4 deg C of OAT error would result in about a one knot error in the calculated TAS, at RV cruise speeds.

 

[kentb]

Kent,

Are the two EFIS systems plumbed to the same static, pitot and OAT sources, or does each have its own? I'm wondering whether the differences between the two EFIS systems are simply due to their instrument errors, or whether they have different input data.

Which static ports do you have? Looking at your data, I think there is a good chance you have flush mounted static ports. Any chance there is a static system or pitot system leak?

Where is the OAT probe(s)? Every 4 deg C of OAT error would result in about a one knot error in the calculated TAS, at RV cruise speeds.

I am using the pop rivet static port (one each side) as per Vans plans. The static and pitot line are tee a number of times to get to all the instrumentation. Each EFIS has its own OAT probe and it own magnotimeter.
The pitot tube is Dynon heated version mounted in a Gretz mount.

I think that there may be a small leak in the lines/instruments, but have been unable to find it. The leak could also have been in my leak testing equipment.

Larry, give me a call if you need help with something. Lets take that plane to Oshkosh this year.

Kent