Hi Jim, Good to hear from you again. Build on, v4 is at least a year in the future. We are still in design/bread-board phase and Lenny wants to mature spin detection in v3 in the near-term. Cheers, Vac

V4 is in design. We are still working through IMU development with the V3 hardware. It’s a bit of a challenge to get required performance from an inexpensive IMU without GPS…Not going nearly as fast as we’d like 🤔. The Teensy 3.6 in the V3 is currently unavailable and will likely remain that way. V4 will be ESP32 based. We continue to plug away, Vac

ring me up when convenient. 850 974 4472

Max, what time zone are you in? Probably best to chat with me or Lenny.

Max, drop me an email at vac@flyonspeed.org and I'll send you draft pubs with set-up instructions. Cheers, Vac

Max, We are with you. V4 (the next hardware configuration) is going to be a clean sheet design. We also want to step away from the Arduino development environment. It's a great environment for a hobbyists, but too complicated for non-computer savvy folks (that includes me) and has other issues for avionics application. I just responded to a "parts wanted" post on Van's Air Force. The current component made of unobtainium is the Teensy 3.6. We don't have any, nor have we been able to source any. We are canabalizing whatever we have on hand to keep the engineering test flying going. Cheers, Vac

Hi Gareth, I'll leave 1 and 2 for the engineers; but as for your third question/point, the real purpose of the IMU is to enable automatic calibration. If your airplane has an EFIS, then that input would suffice as you are correct that the IMU (currently) doesn't contribute to the AOA solution. Lenny has talked about running the code on the WiFi chip, so that also sounds plausible. It would be an interesting drill. Cheers, Vac

Hi Marc, In that study, there were three sensors, one was static pressure and two measured "Pfwd" and "P45." Dave et al concluded that the third static sensor was not necessary. We are currently using the same configuration normalizing using local pressure, in accordance with the study you reference. We do use the static sensor to compute AOA, but that is used for deriving airspeed and some other information in the data stream. Vac

It's about 12:1 (light weight, fixed pitch prop). Actually, for turnback performance, the climb angle to glide angle ratio is what's important--if it's greater than 1, you can generally turnback after reaching minimum turnback altitude. Since the -4 has such low power loading and good climb performance, it's got a fairly low minimum turnback altitude. The great maneuverability helps. You are correct: when I say "energy looks good" it's just an indication I've got a warm fuzzy that I'll make the field. With power available, an "on speed" condition is also neutral excess specific power, so thrust and drag are balanced for a given weight (gross weight x G). An on speed glide is actually maximum endurance glide. So in those sense as well, "energy" is good. In other words, your prosaic understanding as well as your observation are correct. The RV-4 has almost no natural stall warning at low G, and limited buffet even at high G. The progressive stall warning the system provides is outstanding. The nice thing about an RV, is if the stall doesn't result in a departure (spin), recovery is prompt. In a loaded turn, there is a distinct loss of lateral stability. I can't offer any gyro plane advice or opinon--well outside my field of expertise; but sure seems interesting! The "eyes out" functionality of the aural cues is really outstanding. Once you get used to flying with this much alpha/energy feedback, you feel naked in an airplane without it. We've noticed that as folks transition to alpha for approach and landing, one of the first things they realize is that they were carrying too much energy (airspeed) when they were only referencing the airspeed indicator. I sure appreciate the note, Vac

Yes, it will work fine. I spent some time in a previous life working with sub-scale drones (the old-fashioned jet powered ones!) and there was always a significant pendulum effect with the pod mounted engine--they were mounted below the fuselage, so opposite of the Subsonex. There is even some effect in the 777 I fly at work. That won't effect coefficient of pressure derived alpha.

Drop me an email at vac@flyonspeed.org. Cheers, Vac

Hi Dale, Sorry about the delayed response: No, but best if it's relatively close to the longitudinal axis of the airplane. We are working on integrating the IMU, and that placement may be helpful. Lenny has the WiFi interface set up so that you tell the software what the box orientation is. You can mount it using screws if you attach the flanges to the box, or we've also been using the industrial strength velcro, which has worked well too. Cheers, Vac

Hi Dale, Yup, possible if you have a Dynon AOA probe on the airplane. However, that would mean it's pretty simple to add T connections to the existing 1/4" lines to connect directly to the Gen 2 box. More accurate than using the Dynon AOA signal. You can get by with a single curve calibration in an RV-3/4/6/7/8 if you don't have a flap position sensor. RV-9/10/14 need a flap position sensor because of the slotted flaps on those airplanes. Cheers, Vac

Hi Jim, The current hardware is still version 3.0. We’ve been collaborating on the instructions and think someone may have relabeled the most current version “3.1.” Sorry about the confusion, and good catch. We’ll fix that.

Jim, Thanks much! Very generous of you. Cheers, Vac

Mark, 50 degrees is a good place to start, and the inspection plate will work. That probe needs to be aft of 26% mean aerodynamic chord, and the inspection plate should work for that. We've only tested at 45 degrees, which resulted in a polynomial fit for the aircraft curve, and that type of probe SHOULD result in a linear fit. We originally "hard mounted" the alpha systems probe at 45 degrees in the RV-4 test bed, but we are currently modifying that mounting, to use the adjustable mount so we can adjust the angle. Depending on when you start flight testing, you may be ahead of our testing of this probe, so we'll help with the calibration. Just keep us posted. We are concentrating on software testing and auto-calibration; but will get the "auxiliary" AOA probe on the RV-4 bolted back on soon with the adjustable mount so we can commiserate. v/r, Vac

Hi Jim, Yes, the current version is Gen 3 V3. There are some minor changes to the board design. We've got everything updated on Mouser, so the parts list is current. Besides the board, there are a couple of unique components in the box. We machine the aluminum end plate to accommodate the pressure fittings and DSUB and have a custom made plastic plate for the other side to allow wifi/bluetooth connectivity. There is also a small, brass three way fluid fitting we use to distribute pressure. We've got a small supply of these parts if you're interested in joining our group of assemblers. We've got five folks currently building six boxes. They are updating the assembly instructions from V2 to V3 standard. Send me an email at vac@flyonspeed.org if you're interested in following along or participating. Cheers, Vac P.S, nine time zones which direction (Switzerland, I presume)? I fly for FedEx and do a lap around the planet once a month so I can buy 100LL for the mighty RV-4. Also, we can always use a software engineer if you've run out of other things to do in your spare time.

Hi Tom, The box is aluminum, but one of the small sides is plastic to allow the WiFi to work. Cheers, Vac

Tom, You have passed my expertise! I’ll send a note to Lenny to have him chime in to this thread. If you don’t see a post, email him directly at lenny@flyonspeed.org. Cheers, Vac

Hi Tom, Sure is. Lenny and Chris just consolidated everything here: https://github.com/flyonspeed