I definitely spent a lot of time trying to get some hard numbers for what kind of performance people would see in the Tsi at altitude. When you chat w/ the guys at TAF there's a rumor floating around that there was a head to head competition between the Tsi and the RV10. Below 10k feet the RV10 was the clear winner, but higher, the Tsi apparently was gaining a lot of ground. When asked about it being published there's a lot of himming and hawing about it. I'm not really sure what the deal is there.
I went with TAS simply because math and I aren't the best of friends and I'd hate to put something out there wildly wrong. So when I posted my blog post I tried to be as honest with the numbers as possible. Boldmethod did the 4 types of airspeed at
https://www.boldmethod.com/blog/lists/2 ... ach-works/ and under point number 2, they do reference the same information you have of "So at 10,000 feet, true airspeed is roughly 20% faster than what you read off your airspeed indicator." Another good reference (which I used the slide in my blog post) is at
https://youtu.be/p22FOawoTCM?t=694, and I've come to find the videos that Savvy does to be very informative. A bit dry, but still the material is good.
I also stumbled across this video of an RV10 driver who was demonstrating his LOP to FL200, which is kinda cool, but I was watching it mostly for the airspeeds he was getting not so much his fuel consumption. If you look at this frame
https://youtu.be/FgXH-1VJl44?t=342, he's at 16k with a 39kt tail wind with a TAS of 152ks and GS of 196kts. Then if you go to
https://youtu.be/FgXH-1VJl44?t=347 which is a bit later in the flight, he's at 18k with a 46kt right x-wind showing 156KT True and 160kt GS. His engine is down to 15.5" on the manifold, so he's way off his full power, or even 75% power.
The FL300 flight test they did in the SlingTsi (two people, more differences in weight of course) doesn't have any good up close panel pictures, but from this frame
https://youtu.be/Yn9PU-crXYw?t=576 they are at FL160 with a GS of 141kts and still climbing at 768FPM. The next point of reference they are at FL250 and I'm not even gonna pretend I'm ever going to fly that high in the Sling.
Bottom line is (for me) I certainly want to go as fast as possible (and try really really hard to not be smug about it), but at the end of the day, this is the plane I'm building and planning on keeping for a long while, so whatever it trues out to will be fine. But the meager math I've done seems to suggest that with O2 it will be able to be pretty zippy in the FL150/160 range...
If I'm missing something, or need to correct my thinking on any of this, by all means, please let me know. I'd much rather be corrected than wander around wrong all the time as that's just embarrassing.