- Nov 14, 2009
- Rocky Mountains
It would seem that the confluence of more recent high performance hang gliders, Part 103 true sailplanes like the Sparrowhawk, and Marske's Monarch/Pioneer series might essentially render the Minibat concept obsolete???The Minibat concept wasn't necessarily bad, it just needed better execution.
Couple of things. For one, it would fold into a smaller package than the Monarch, but have close to the same performance, better than the ATOS for ridge-soaring, IMHO.It would seem that the confluence of more recent high performance hang gliders, Part 103 true sailplanes like the Sparrowhawk, and Marske's Monarch/Pioneer series might essentially render the Minibat concept obsolete???
Meaning... if you created an aerodynamically safe and structurally sound version of the Minibat, what would it do for you that other current designs could not do better? I would guess the Monarch would soar better and slower in light lift, the Sparrowhawk would run away from it in a race, and the ATOS HG would fold up into a smaller package.
I just read this thread again and noticed that he used sandwich construction consisting of E-glass with PVC cores. PVC foam is good core material but E-glass is not a great choice for the skins. S-glass is about 30% stronger than E-glass and a bit stiffer so a sandwich using S-glass will be a lot stronger and stiffer than one using E-glass for the same weight. The "E" in E-glass stands for "electronic", it was formulated to have better insulating properties than S-glass for fabrication of circuit boards and it should be left to that use. Of course, if you're not on a budget, you could use carbon fiber and end up with an even stiffer wing at a lower weight. Structural glass does have one advantage over carbon though: it is more impact resistant.Hmm... any?
I am specially interested in Minibat wing structure. Any recemblence with AM Eagle wing or it was some different detail approach?
I am courious just as want to know how as made and maybe lear something.. in order not to do such way or even find out something interested.
O.K. I made some searching and find out this article, where:
Minibat construction was unique for the time period. Most of the 18 major parts consist of a PVC
core with Þberglass on both sides and formed in a female mold. A few dozen hardware parts are
sufÞcient to complete the aircraft. Despite the extent of molding and preformed parts, the FAA
determined that the aircraft is 64.5% fabricated by the builder.
The wing consists of molded upper and lower shells of E-glass and foam, a spar using
unidirectional S-glass for the caps, and molded shear webs of glass and foam. The shells are held
together at the leading edge by J-joint, and at the trailing edge by the molded rear spar. The
elevators and ailerons are made from molded glass upper and lower surfaces over glass and foam
ribs. The wing halves attach internally at the centerline with pins. Additional wing panels of about
four foot length became available to increase the wing span and decrease the wing loading. These
extensions substantially improved gliding performance.
The fuselage is built in the same way as the wings, except there is no spar cap. The outer skin
carries the bending loads and the inner skin carries the torsional loads. Reinforcement is provided
in the area of the landing gear, tail skid, etc. Besides a J-joint on the outside, the fuselage is tied
together on the inside by the seat, armrests and keel.
The Þn and rudder are constructed like the ailerons and elevators Ñ glass skins are placed over
Thanks for the Comprehensive replies to all, as Always here on the forum. My conclusion is that is better to put some effort in some other projects even though the Minibat still owns some attractive characteristics... If Topaz manages to find the picture of the wing' cross section would be great since nothing like that is available on the web and would be insiprational for some of us.Oy. It's been years since I made that post. My recollection is that the wing structure was overly reliant upon foam to transmit primary loads near the spars, and that at least the original shear web was nothing but unsupported foam. Both are no-no's in composite structural design, but you have to remember that the Minibat was born during the "Wild West" period of homebuilt composites, when it seemed like everyone was coming out with a new design every other week, and a lot of them were not really professionally engineered. I have a book from the period that has a cross-section view of the Minibat wing, but I moved a few months ago and that book is in a box here... "somewhere". onder: As I recall, the airfoil selection tended to stall prematurely if dirty or wet. It also wasn't much of a sailplane airfoil, in terms of drag.
The Minibat concept wasn't necessarily bad, it just needed better execution. An entirely new structural and airfoil design for the wings would be where I'd start. Given the structural deficiencies in the wing, taking a look at the fuselage structure wouldn't be out of line, either. The high trim drag from the low sweep, and induced drag penalty from it being tailless, mean it won't ever be a great thermalling sailplane, but it'd be a great little ridge soarer if the local geography is suitable.
Well, I dug through a couple of the moving boxes that weren't in storage and found the book for which I was looking, Michael Markowski's Ultralight Aircraft: The Basic Handbook of Ultralight Aviation. The book was published in 1981, at the very height of the Wild-West-like "Ultralight boom", before the '60 Minutes' exposé and the drafting of FAR Part 103. As such, and as was typical of the time, it's a pretty "optimistic" view of what ultralight aviation was then - basically anything that could be foot-launched. Since the Minibat can't be foot-launched, I'm not sure why it's included, but it is.Thanks for the Comprehensive replies to all, as Always here on the forum. My conclusion is that is better to put some effort in some other projects even though the Minibat still owns some attractive characteristics... If Topaz manages to find the picture of the wing' cross section would be great since nothing like that is available on the web and would be insiprational for some of us.
Possibly but, since the face sheeting material is specifically called out everywhere else in the diagram and there's none here, and since I've been told the shear web was foam-only, I interpret that as meaning "foam only" despite the use of the word "core". Perhaps I'm wrong, but this interpretation matches what I've heard elsewhere.The spar web call-out on the drawing does say "foam core" so apparently the rumor of the simple foam web was overstated...
There appears to be reasonable interest in a small, light, simple, (as in fast build) flying wing. As a design exercise and a configuration study, what would it take to convert the Mini Bat design into an ultralight flying wing.the molds for the outer mold line of the pod could be adapted to any design.....lot of work saved if you like the shape.