A recent thread titled "Neglected homebuilt niche?" (see https://www.homebuiltairplanes.com/forums/showthread.php?t=28882) started taking about a tube-gusset-and-fabric, O-235-powered PGK-1 Hirondelle to slot in under the RV-9 in the kit plane market and eventually ended up with the idea of a microlight/LSA RFB Fantrainer (see http://www.fanjetaviation.com/technologies/fanjet-600/). I'd like to explore the idea of a modest cost, modest performance, easy to build, pseudo-jet a little more. Here are a few approaches that I have kicked around: DUCTED FAN A number of ducted-fan homebuilt designs have tried to give a jet-like experience at piston cost but none have ever really taken off (groan, I know). One new example is a carbon fiber L39 Albatros replica (see http://www.skyleader.aero/en/product/ul-39-albi/). The simple fact is that running a high-speed propeller or compressor in a duct efficiently is not that easy and most such designs seem to end up quite expensive for the performance they offer. LONG DRIVESHAFT Others have kept the propeller on the nose but moved the engine back like a P-39 Airacobra, or put the propeller at the tail like the early Bede BD-5 and many others, but both of those require a long driveshafts between the engines and props that add weight and introduce torsional vibration issues that have bedeviled many such installations. The pusher prop in the tail does seem like it would work well with a very light two-stroke engine that could be balanced by pilot weight alone. PROP ROTATING AROUND STRUCTURAL ELEMENT Another approach, which I have seen in relatively simple form on the Mignet HM.1000 Balerit, it to use a fuselage structural member as the axle around which the propeller rotates. There is a gyroplane that does the same thing with a prop rotating around a cantilever tail boom, which looks very slick but is much more complex to execute. There were even some WWII conceptual designs that had props rotating around around the entire rear fuselage. This approach requires pretty specialized mechanical installations (except for the relatively simple Mignet version, which cannot easily use direct-drive engines or existing redrives) but has the advantage of allowing large-diameter props. JUST FAKE IT So where does that leave us? To keep things simple, I would like to avoid ducted fans and long driveshafts and specialized mechanical installations. I am also willing to go with more of a "profile model" approach which mimics the general outline of a jet but not the full 3D structure. What I have come up with so far is to go with a traditional pod-and-boom pusher layout (irrespective of wing position) like the Kolb designs or the Sky Arrow, but essentially build up a low aspect-ratio fin on the boom to mimic the side view of a jet trainer. I could even see going so far as to put a hollow cylindrical spinner on the prop that leads to (but does not touch) a bullet fairing on the fin to give the illusion of a continuous structure even though the single boom is actually doing all the work. Here is the butchered Electraflyer image that I posted in the other thread: I think this approach could yield a simple, lightweight, two-seat design with jet-like looks and staggered tandem seating that could be adapted to any of various engines (Suzuki, Rotax, D-Motor, ULPower, etc.) around 100 hp. Despite the looks, it would have fixed gear and performance appropriate to the power, size, and weight. Perhaps there could be microlight (big wing and low gross weight, good on short fields), LSA (similar wing but higher payload and longer takeoff/landing runs), and E-AB (smaller wing needs longer runways and lands faster but has higher cruise speed) versions. OK, fireproof undies are on.... ;-) Thoughts? Cheers, Matthew PS--The propeller "slot" in my concept would actually be triangular (larger near the propeller tip, smaller near the hub) to give the prop more space to "breathe" and because RFB found in the Fantrainer (and the civilian Fanliner with Grumman American, see https://en.wikipedia.org/wiki/RFB/Grumman_American_Fanliner) that sweeping the structural elements downstream of the fan reduced noise as the slipstream beat against the structure. Presumably that would also apply here, and I don't think the triangular gap would ruin the jet look. INSPIRATION This is just an RC profile model of a T-45 Goshawk with a little motor in the tail, but I am posting it to show that a "profile model" approach can still capture the lines of a jet and look cool, at least that's my feeling.