Next RV model. The RV-1010

[rocketman1988]

I always loved the Wing Derringer...too bad they are a pretty rare bird.

Twin Comanches are nice but probably the biggest bang for the buck is a mid 60's C-310...

[1001001]

I'm holding out for the RV-20. Six seats, engine options: single Lycoming iE2 or PT-6. VNE 350 kt (level flight achievable). Factory wing hardpoints for drop tanks / JDARC (Joint Direct Attack Rubber Chicken) pods.

[rocketman1988]

...and a $1,000,000 price tag...

[David Z]

A good twin needs to be able to take-off with one engine. All the airliners are capable of continued take-off past a certain point during the ground roll. That second engine is of no use if it takes you to the tree line at the far end of the airfield and the rejected take-off puts you into the ravine.

A 6 seat twin likely needs a 250-300hp per engine to achieve this, depending on the aerodynamics and pilot technique. A 4 seat twin likely needs IO-390s. An automatic propellor feathering device would certantly help as well, although that's pretty complex to design properly.

[JDeanda]

My $.02, worth $.01. After 40-odd years in the little airplane business, I’ve only seen one light twin that I’d even consider owning. The Wing Derringer had 160 hp per side and only two seats, which might provide some useful climb performance on one motor. When Piper, Beech, Champion or Grumman made twins out of existing singles (Twin Comanche, Seminole, Duchess, Lancer, Cougar), they ended up with multiengine trainers, not better versions of the airplanes they started with. (eell, the Twin Comanche wa a bit demanding for s trainer) Airplanes designed as light twins from the start fared only a little better. I believe current piston engines lack the power to weight ratio to do an adequate job. Building a twin from even a well-executed kit is nothing I’d ever consider. I love our RV-6.

[rocketman1988]

I had a 1964 Cessna 320 Sky Knight. It flew great on one engine; fast and roomy...

The C-310R is a really nice twin, too. It also flew fine on one engine.

Now the early model Apache...not so much...

[rongawer]

Originally Posted by David Z

A good twin needs to be able to take-off with one engine. All the airliners are capable of continued take-off past a certain point during the ground roll. That second engine is of no use if it takes you to the tree line at the far end of the airfield and the rejected take-off puts you into the ravine.

A 6 seat twin likely needs a 250-300hp per engine to achieve this, depending on the aerodynamics and pilot technique. A 4 seat twin likely needs IO-390s. An automatic propellor feathering device would certantly help as well, although that's pretty complex to design properly.

I think you may mean that a good twin needs to be able to climb on one engine. I do not believe there is a certified twin, piston or jet, that allows take off with one engine inoperative, but your point is valid.

The early Apaches defined the often repeated joke about "flying you to the scene of the crash" as its single engine ceiling was near sea level. The B58 Baron, on the other hand, has about a 9,000' single engine ceiling. I've have had an engine failure in flight in my Baron and simply feathered the prop and continued to the nearest field to an uneventful landing, no crash involved. There's no way to know how often those events happen as it's not required to be reported, but I imagine it's a recurring event. If you're trained and proficient, it's not a big deal. If you're not prepared, it is absolutely unforgiving and deadly.

The 6 seat aircraft you've spec'd is a solid Baron and the 4 seat would be a Piper Commanche. Both good, stable twins. The issue with them is that they're not experimental nor inexpensive to own and operate (I owned a B58 Baron for many years and still have the mental scars of parts and labor costs {side note, I was weighing the cost of a custom made SkyDynamics sump and intake and then remembered it cost almost $7,000 for a new starter adapter for an IO-550 on the Baron [that's not the starter, just the Rube Goldberg gearbox that the starter mounts on], and suddenly, that cold air intake with sump seemed inexpensive. Yeah, I bought it}). And although fuel isn't actually twice the cost, it's a lot. I owned a Bonanza and a Baron and I can tell quite accurately that a B58 fully loaded is about 36% more expensive in fuel than a fully loaded A36 Bonanza when calculated block to block. Those two airplanes share a common airframe design and are about as good an example of what you could expect by comparison if the RV-10 became a twin, although a comparison of the Velocity versus Velocity V-Twin is another good one and experimental too; I just don't have hands-on experience with both like I do the Beech's to provide meaningful data.

The thought of a twin RV-10 is interesting though. If you're thinking to go faster, or just thinking twin engine to have the extra engine in terms of flying over the mountains, at night, in IMC...the trifecta of instrument aviation - you should consider the Velocity V-Twin. It's about $250K+ to build and a lot more hours (and I hope you enjoy composite work...), but it is very nice airplane. I came very close to buying a kit a couple years back, but then decided on the 10 after meeting with a couple V-Twin builders and coming to the conclusion that it will take closer to 4,000 hours to build (and I'm hoping to be flying it with a little life left to enjoy it). It would be fun to have though, if you can get past the construction time and cost.

Second side note: I laugh when I read folks talking about cost cutting on their airplane builds, saving $10 here and $50 bucks there - all the time I'm thinking that buying
"expensive parts" for an experimental airplane compared to parts from Beechcraft is like comparing getting hit with a fly swatter versus a sledge hammer. Aside from the idea that penny pinching on an airplane that may have cost you north of $150K to build is ironic, the cost of a twin is an upward parabolic curve. The starter adapter example I gave is one thing, but consider the cost of buying and building an elevator for your RV-10. Now consider that a new elevator for a B58 Baron, in 2017 mind you, was $23,000 PER SIDE. I'm not sure that it's $1000 for all the parts to build a complete RV-10 elevator, but it's in that ball park - a much smaller park to play in.

I say all that to make the point that thinking about twins is fun, AND, I thoroughly loved flying my Baron, BUT, the cost of owning and operating a twin - even an experimental twin, is MUCH higher than the wonderful RV-10. Even more so, the importance of recurrent training One Engine Inoperative and being highly proficient on your airplane just about mirrors the O&M cost. Have fun, just have the right expectations, and bring your checkbook.

[SPX]

Originally Posted by rongawer

I think you may mean that a good twin needs to be able to climb on one engine. I do not believe there is a certified twin, piston or jet, that allows take off with one engine inoperative, but your point is valid.

You're right that with most jets, you can't start the takeoff with an engine inoperative (some you can -- A380, B747, etc). However, with any transport category certified jet, it must be able to continue the takeoff after V1, and fly with an engine inoperative.

[KRviator]

Originally Posted by Denok

The next RV should be a twin IO-360 powered aircraft with available FIKI. It should be the size of a 10 and a good IFR platform.
There...I said it.

Put a pair of Rotax 914's in it. 200HP available to FL160! And you can run Mogas... Two of those together probably aren't far off a new IO-540 with prop and accessories, and I'd guess 100lbs lighter.

[rongawer]

Originally Posted by SPX

You're right that with most jets, you can't start the takeoff with an engine inoperative (some you can -- A380, B747, etc). However, with any transport category certified jet, it must be able to continue the takeoff after V1, and fly with an engine inoperative.

It might seem like splitting hairs, but continuing a take off after V1 with a failed engine is different than initiating a take off with a failed engine. Also, neither the A380 or B747 are twins. The POH for a Baron states that if an engine fails during takeoff to shut the throttles and do maximum braking. The same is true for a Diamond and Cessna twins, but I do not know if it's in all twin flight manuals.

However, a twin RV-10 would not have a V1, nor would it be certified, so it would be up the builder to decide. If you're in a hostile situation and you're going to die if you stay on the ground, give it a go, but realistically, anyone who has taken multiengine training knows that the worst case scenario for a twin engine aircraft is an engine failure on take-off (slow, heavy, gear down, asymmetric thrust, etc) - statistically, it's a high fatality rate. The only advantage of starting the take-off roll with OEI would be that you already know it's failed and hopefully prepared for it; but just because something is possible doesn't mean it's profitable; I do not advocate doing it.