That parallels my experience as well.. mine was essentially a flat plate equilateral triangle delta with a central rudder, AR~2. I was able to turn it without using ANY rudder input (elevons only), but a modest amount of rudder allowed it to carve cleaner, tighter turns.. I could also turn it with rudder only, but not quite as easy. It would maintain lateral control, even at very high AoA, nearly vertical descent.... next step is to build an improved version with motor & prop.I have a delta planform model made of flat foam that has a central fin and rudder. The rudder is effective. Adding it made a significant improvement n slow flight at high angles of attack.
hehe, I agree. Pinterest is not to be regarded as a useful tool. Just for entertainment and fun. But sometimes one of the things view'ed as entertainmant, gives a little spark of interestPinterest is a time wasting site, as it doesn't distinguish between delusions, concepts, plans, aeromodels, prototypes, or production machines. Terrible!
Thank you for your comments. I watched your videos several times over the years. Always liked your low aspect designs. Since you experimented with scale models and given your building experience, I'd like to pick your brain a bit if you don't mind:As I have said before designing even the simplest of aircraft is a non trivial task. With that said, it is possible for a non professional to design a successful aeroplane, many have done it including myself.
Your summary is spot on, obviously you have an idea of what your dream will look like, if you are still open minded, consider the flyability of your dream, things like vision can be a deal breaker, the FMX4 had clear panels in the floor.
I have built a number of LAR faceted models and simple flying wing glider models to study planform effect, the faceted models taught me that LAR behaves in a very different flight regime than conventional wings, even a flat plate will fly well if the planform is correct and the aspect ratio is low.
even faceted airfoils can provide a good L/D, if you study the engine out glide of one of my models You will see that the L/D is not directly related to span.
Thank you. Vortex lift starts at around 7-8° AOA, you would need 'huge power' to counter the 'huge' drag at high alpha. Sure a low aspect design could fly at a 30° AOA or more but does it needs to? The Useless Flying Object, for instance, lands at a pretty 'normal' AOA from what we see on the videos.Nice refresher.
You only commented on the pros. The biggest drawback i see, is that in approach attitude you wont be able to get out of vortex mode unless you have huge power or time to drop the nose significantly or both.
I too would like to see a Piana-Canova inspired design being built and flown. My point is that we should be able to have a good enough idea about how the airplane is going to perform before it flies. Obviously it should be easier to do so with a Piana-Canova/Payen/Arup type of airplane with conventional airfoils and not relying on vortex lift. You're probably right, maybe the simplest way to LAR is by using conventional airfoils, straight lines and not rely on LEV.Personally, I would love to see more experimentation with the Piana-Canova rhomboidal planform just because its straight lines make it so suitable for quick and easy construction. It would be great to see a basic VW-powered PC-style single-seater to compare with other single-seat, VW-powered designs out there to get a concrete comparison of a straightforward LAR designs with other more conventional designs of similar weight using similar engines.
Because the best lift to drag ratio (and thus cruise) of most airplanes is at a CL of about 0.2 which will be at an AoA well below where the vortices are big enough to have much effect so an efficient cross section would be nice for cruise efficiency.Norman mentionned the fact that a wing below AR=2 will be entirely engulfed in tip vortices. At this point why even taking 2D models and values into account?
I probably misread your post. What I understood from your earlier post is that wingtip vortices, on a straight wing without taper for instance, will affect the entire wing at or below AR=2. If I understand correctly wingtip vortices are always there as long as the wing generates lift.Because the best lift to drag ratio (and thus cruise) of most airplanes is at a CL of about 0.2 which will be at an AoA well below where the vortices are big enough to have much effect so an efficient cross section would be nice for cruise efficiency.
I think the FMX4, with vortex lift, managed a CL around 1.0. So start there. I extracted numbers from Barnaby's PAV report. That will need sharp leading edges. I am highly suspicious of claims of high CL for low AR. Barnaby is a very talented guy. He designs 'real' aircraft at his day job... If he could only get around 1.0, that only confirms my suspicion of experimental error in the old low AR designs. Measuring speed accurately at high AOA is not a trivial matter. A pitot-static will read very low.OK, well here's where the rubber hits the road and where I don't have the math skills or engineering knowledge to answer the question. What sort of CL max is a reasonable estimate for something like a Piana-Canova design at a AR of just under 2.0? With some sort of basic rule of thumb I can estimate minimum speed and size the wing accordingly. Since Part 103/SSDR and microlight/LSA categories all have minimum speed and maximum weight requirements, that wing area required for stall/landing speed is the key factor that drives most of my conceptual designs.