Two Rotax 915s plus two controllable pitch props? Oops, I think I stumbled into the wrongThis is one area that technology has finally caught up with us dreamers. The rotax 915 offers a true single lever FADEC automatic constant speed prop system from a certified engine now. Jet engine like control simplicity. It's also a big part of the dream. Lose an engine and you pull one lever back. Everything wired into a Garmin or Dynon that will flash warnings at you as it monitors engine stats. Pair of turbo 140hp engines on a 2 seat twin is plenty of power for excellent performance on two or one engine.
Sorry, I don't know. The subject did come up before in the Beetlemaster thread. I thought wing lift struts would be handy for managing the tail boom loads, Autoreply suggested that feeding them into the wing skins would be more appropriate (assumed composite construction?). More here (including a link to an article based on interviews of the Cessna 336 designers) and here.Definitely going to take a rethink at the push/pull set-up. How hard is it do a cantilever wing with booms ? Is designing a structure that can pass through all the different loads the wing spar now has to handle hard to deal with ?
Yes to both. Strong climb and cruise. Mission goal is fast, efficient, low pilot workload, night or day / rugged mountains or open water cross country cruiserTwo Rotax 915s plus two controllable pitch props? Oops, I think I stumbled into the wrong
tax bracketthread. 280 HP in a two place airplane--so, what is the mission? With that much power and just two seats it sounds like you either want to climb quite quickly or go quite fast (250+ MPH would be quite doable with this power and a clean airplane, even with the big-ish wing required for acceptable SE climb). If you want to go fast, then retractable gear starts to get attractive, and a low wing makes a nice spot to stow landing gear. At least one of the engineers who designed the Cessna Skymaster said that they would have used a low wing if they'd known from the start that the planes would eventually have retractable gear.
That remind me that i saw a rotax powered Defiant for sale in France in the last few months.it will probably startout with a pair of cheaper 912s to keep cost in check while testing aerodynamics.
Sounds mighty complicated compared to the Boomerang layout. Have fun...Yes to both. Strong climb and cruise. Mission goal is fast, efficient, low pilot workload, night or day / rugged mountains or open water cross country cruiser
At the end of the day the whole point of having two engines is single engine performance in an emergency. In that scenario there is no such thing as too much power. I am hoping to have a plane that can do 200kts at 10-12,000' and 500 fpm single engine climb up to 12,000+ Density Alt. I wish the 915's were cheaper and something like the Apex engines or big bore Rotax 912 should power the airframe quite easily. If I ever do get to a flying prototype stage (not holding my breath, but will strive for it over the years) it will probably startout with a pair of cheaper 912s to keep cost in check while testing aerodynamics.
With the current dream of a 3LS layout I envision something about the size and shape of the small Velocity SE (with more shoulder room), with a wing and interconnected flap layout like the Eagle 150 (low canard up front, center mount for main-wing and conventional T-tail), Twin pusher Rotax 915's, and landing gear from Cessna 177/182 (circa Lancair IV). The flap interconnect system between the two wings has already been figured out in the Eagle 150, just need to see how they did it and make something similar. Same with the gear retract. No need to reinvent the wheel with these sub-systems.
Nothing written in stone. That's why I'm here bouncing ideas off you guys. I may end up with a simple conventional twin like the Derringer or maybe something that looks like a 177RG with two engines on the wing, or a push/pull set-up. Following unrealistic dreams is a surefire way to a dead end road .... lesson learned from the Raptor project... (and Beech Starship) to not try and force the mission to fit the plane you have locked in your head.Sounds mighty complicated compared to the Boomerang layout. Have fun...
May I suggest a Seneca? A friend of mine is selling his Seneca III (I think), because he's upgrading.Yes to both. Strong climb and cruise. Mission goal is fast, efficient, low pilot workload, night or day / rugged mountains or open water cross country cruiser
At the end of the day the whole point of having two engines is single engine performance in an emergency.
Hence my question on the Pond Racer style set-up. CG balance concerns ? I would want to lose the two engine booms though and just have a fuselage behind the wing.What about putting both engines close together so that the prop arcs are almost touching? That can be done with forward engines (and maybe prop shaft extenders) and balance it out with fuselage length and rear loaded payloads on a tractor config. You can do it on a canard too.