They achieve "total performance" by having slick airframes and adding even more ponies to the front. There is a reason there one non-aerobatic aircraft cruiser that uses minimal horsepower(rv-9) is already undergoing Rotax testing.
By the time you are at 4000 feet above sea level, a Lycoming o320 160 horsepower engine will produce less horsepower than the Rotax 916is at 137. If you can climb to 4000 feet in under 5 minutes(if you takeoff at sea level in 59-degree weather), or you already live somewhere with high density altitude, the Rotax is worth looking at. Turbos make a lot of sense if you live out west. The biggest problem with them is their price, and they are not drop in o320 replacements due to CG.
The premium you pay for a 916 is partly offset by the convenience of availability. There’s not a lead time if you need one tomorrow.
No limits whatsoever. You could hang an r4360 on it if you beefed up the right places.;-)
Also there is a $10k rotax cost differential.... and while rotax engines are common... would you rather break down in a o-320 or a rotax??
No. As an E-AB aircraft the owner is free to do what they want. But by going with Vans suggested engine you get factory support, known performance figures, and a factory firewall forward kit.
The 15 is designed as a backcountry bush plane, not an X/C cruiser. As a result you want that HP on takeoff. Consequently HP comparisons at altitude are meaningless.
The RV-15 is literally a cross-country capable STOL aircraft. It has 140 knot cruising speeds, according to Van's. And yes, 140 knots is enough for cross-country flying.
Most backcountry areas, other than Alaska, are literally in the mountains, where density altitude numbers matter. Granted, most people don't use their STOL plane for backcountry purposes, as discussed in that other thread about carbon cubs for sale. It just depends on where you live, if turbos make sense.
Ha! But nah, they’re still out there; I was at Johnson Creek ID last month, the STOL bros had me surrounded.
It was not designed with X/C in mind as a criteria— period. The fact it will do 140 is just a bonus.
Someone modded their rv6 and made it a twin.
At the same propeller rpm, the prop doesn't know the difference between a slow turning large displacement direct drive engine and a smaller fast turning with a redrive.
Ok, so it's the prop that's the difference, not the engine displacement or crankshaft rpm.
2 actually, although one crashed during a high speed taxi test gone awry that resulted in inadvertent flight. There’s also a radial powered RV-8. Plus tons of auto conversions from Subaru’s to LS1 crate motors. The FAA nor Van’s gives a crao on what a builder does as long as they follow the E-AB certification process which is mostly an exercise in properly filling out and submitting the requisite forms.
I don't think this is true at all. Go read the Vans web site. Read all of the development updates. Sure, it's a bush plane, but it's also obvious that hitting the promised 140 kts cruise is very important to them. It's not a happy accident. It was a design point from day one.
It actually has cutouts to accept the bike tires.
Well I’ve talked to Vans folks, was at the banquet when it was announced, and have examined the original prototype and the current iteration up close and personal. I stand by my assertion that X/C performance was not a primary design consideration.
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