Rob,
An experimental test pilot buddy of mine has an RV-4 with a sport system. We are going to strap a Gen 2 V3 box in the airplane and test the feasibility of using AFS-style wing ports as the coefficient of pressure source for V3 as part of beta test. We'll instrument the airplane with a calibrated test boom; so we'd be happy to test new software/tone logic in the sport simultaneously. I've been running the Dynon-based Gen 1 system (tone generator only) in my test airplane simultaneously with Gen 2 (full up AOA computer with IMU); so we should be able to do the same thing with an AFS system and a V3 box (i.e., allow the pilot to listen to simultaneous audio signals for test and evaluation). We record all data (pressure sensors, IMU, boom and EFIS) simultaneously to the V3 SD card for analysis--we could probably figure out a way to shoehorn sport data in there as well. We use GPS time to synchronize data. Data is downloaded from V3 wirelessly post-flight.
We've found one aircraft curve is sufficient for the RV-4 equipped with a Dynon sensor for all flap positions, but the software is capable of accommodating multiple curves. We normally run three (one for flaps zero, flaps 20 and flaps 40) for test purposes to stress the software. We are using GPS speed runs to derive curves and initial set points based on physics/aero using Dr. Rogers technique spelled out in DOT/FAA/TC-18/7. We can determine the optimum number of curves required analyzing the GPS speed runs in different flap configurations. Lenny is working on a wifi interface to allow real-time adjustment of settings in flight via iPhone. This will help with fine tuning set points as well as allowing the pilot to adjust damping for test purposes.
We'd be happy to collaborate or assist. We are a non-profit, open source group of volunteers trying to bring some stuff that worked well in the military into the EAB/GA world...If we can help one pilot avoid an unintentional loss-of-control situation, it'll have been a good effort.
Hardware schematics and software are available on our website (
flyonspeed.org) and GitHub. Obviously, we are biased towards accurate, performance based AOA/energy cues that can be used as a primary eyes out reference for maneuvering and approach and landing. We just started experimenting with 3D (stereo) audio to use the tone to also provide a yaw cue (using data from the on-board accelerometers), which is kind of nifty. Uses either a stereo input in the ICS or bluetooths to a stereo headset in airplanes without stereo ICS capability. One of the primary objectives of beta test will be to determine the feasibility of fully automating the calibration process.
Oly,
If you have a wingman with a soldering iron, we have a couple of extra boards laying around. Parts list is on the website and we'll help with tech support. Drop another line if you gents want to give it a go. Gen 2 V3 works well with the Dynon probe. The number of curves you need depends on airfoil, flap configuration and probe location. Since the -8 has essentially the same wing as the -4, likely it will look very similar. Regardless, you still need a flap position sensor for the various tone set-points--very easy to add one to the RV-8. Without one, it's
sort of practical to optimize ONSPEED cuing for Flaps 40 and start of the flaps tone with L/Dmax; but I don't recommend that. I've got a blog post up that explains these plots if you're interested in the aero or how the software uses the math. We'll be starting Garmin probe testing next week. Rob is spot on with L/Dmax shifting as you deploy flaps; but effectively it just slides into the ONSPEED band (which is the way it worked in the jet BTW--we just added the feature for straight wing props to the Flaps 0 logic so you can hear Vy, max range glide and max endure). That's why the caveman simple "turn now/set lift flaps/maintain ONSPEED" plan works when the engine quits and you have to BFM the runway:
https://youtu.be/trnwzBYvBQg
Here's what the three curves look like when they are plotted together. The fact that they largely overlay each other means the airplane is a candidate for a single curve calibration:
You can collapse these curves into a single one that's still very accurate (that's indicated by the high R2 value under the equation):
For the RV-10, however, you can clearly see that a single curve isn't gonna' cut it:
If you do decide to build a system, once it's in, it would be fun to see how it works in a one-circle fight
Alternatively, we are finishing up production of 25 shipsets of Gen 2 V3 (box + harness) for beta test. After we finish designing the beta experiments, we may have a few left over for distribution--I'll go giant voice on the safety page like we did for Gen 1 if/when that happens to coordinate with folks in the VAF family that want to help out. Also, the basic USAF tone logic is available in the Alpha Systems systems.
v/r,
Vac