Geoff_H

A scaled up version could be quite cheap. But it is very inefficient. You could expect fuel consumption to be many times what a Rotax would burn for the same kw. Efficiency depends upon the compression ratio, here I expect about 4:1, and the turbine inlet temperature TIT. The higher temperatures that your blades could take the more efficient. I expect that a turbo prop would be many orders of magnitude higher in cost.

My preferences are for gas turbines. Simple design, very light for the power output if compression ratio is high. With metal 3d printing the number of parts could be reduced to very few. 60%efficiency has been obtained with high temperature turbine blades. They can run on virtually any fuel. Even coal!!!!! On India a gas turbine station was built using coal, well it made coal gas first, fed that to a bank of gas turbines then burner the coal char in a fluidised bed boiler they generated using steam turbines. A small gas turbine with high efficiency would be either very heavy or very expensive. But I would love to power my project with one. You can also get two stroke engines that run on diesel with low pressure injection. Light weight high output. Not sure of the efficiency

The seat would weigh more than the aircraft. But love the thought. Unfortunately the seat in the aircraft forms part of the structure as a bulkhead, yes single seat. Love your comment lol

I like the idea of testing a design, even if it has little chance of final success, you always learn something. Knowledge is never a load to carry. Many years ago I read of people experimental Rotary engines that tacked a third rotor onto the Mazda Rotary, apparently easily done. Obviously a new design of output shaft is required. The reports that I read said that they were having trouble with shaft breakage. The light weight for power would mayke such an engine attractive,even if fuel consumption is higher at high rpm.

For my own design I am installing a parachute! And wearing one! I am also looking at explosive devices to disconnect the wings from the aircraft in case of uncontrollable spin. It has a sidestick so I may, in military style, strap my arm in place with some sort of quick release. Of course A full 150% load testing with sand bags etc will.be done first. Also looking a racing car helmet and brace in case the nosewheel breaks on landing and diggs in. I do expect problems, I am trying to design control of failures into aircraft. I suggest that one reads the reports of all failures reports that you can get your hands on and see if they are applicable to one's design and work out what to do to mitigate that failure should it happen to you

Someone said mirror. When I bought my outback going Mooney the guy that owned it before me had a super shinny piece of metal, quite thin, rather than glass that could fracture in case of accident. I always carried oil on trips across Australia, never know when oil consumption may increase.

This part was 3d printed. A test piece. Each end was bent to 12 mm deformation. It maintained its integrity. More interesting it returned to near its original Shope over the next few minutes. It is very tough, it didn't delaminate. This is so encouraging for the future of 3d printed parts. It weighs 13grams. Is 65x25x12. Carbon infused nylon.

When making parts for the inside of the aircraft be aware that PLA (made from corn starch) will soften an temperatures that are common in summer. ABS is the plastic often used in motor vehicles, use it by preference. I used PLA for some support pieces for a bird restricted system, a week later had to make the 50 odd pieces out of ABS

Having owned a Mooney M20J for many years I can only say that he must have gone into the side of a mountain of something head on. Mooney's are surprisingly survivable. They have a steel space frame cabin, single piece wing spar that attaches under the rear seat and a monocoque tail that moves up any down pivoting about a "hinge" at the rear of the space frame. The Mooney web sites over the years have shown Mooney crashes that were not fatal. I have transited Coffs Harbour many times. I always took the sea path in the control zone. The inland is just too dangerous in IMC. Such a tragedy,.

Landing gear support. Green is proof of design, it was too small and was increased. White part should have been a straight nylon part, it failed impact testing

Pictures show printer with water cooler left. Also the water cooled nozzle and some nylon parts manufactured.

I have designed my aircraft to use 3d printed parts for all load bearing parts except where elevated temperatures are involved. I have used AutoCAD to design the parts. I bought a Leapfrog Create HS. I paid $2.5k when the dollar was much higher, the printer has some serious problems when one tries to print nylon. All bushes in my aircraft are nylon, all load bearing parts are nylon impregnated with carbon. The design of these parts is very different to the conventional steel parts. They are built a but like internal house doors, a honeycomb on the inside and a thin shell on the outside. Nylon and carbon impregnated nylon are around one sixth the weight of Steel, half that of aluminium. I have had to modify the printer that I bought, it now has water cooled nozzles, an aluminium print bed, special nozzle feed (I have developed a nozzle capable of temperatures of hundreds of degrees centigrade) I print at 265 degree Celsius. I have built a temperature controlled enclosure. I am printing the wheel hubs, Azusa injection mould their wheels using the carbon impregnated nylon. They work well. I impact test each print, every now and then I get a layer that didn't weld to the layer below, once because I opened the enclosure to have a detailed look while printing. The parts have been conservatively designed. The purpose of the aircraft is to confirm that a lighter aircraft can be built by this method. I am thinking about designing the flaps using the 3d printer. Experiments with nylon alone showed them to be the same weight as fibreglass flaps and not nearly as rigid.

Can I put my own designed aircraft in RAA? At this stage I intend to be in Experimental GA. But with building problems (using 3d printed parts extensively), it may not be finished for several years, I may have lost my Class 2 by then and need to go to RAA.

Yes I noted them too. They are making non loaded items, and devices. I am modifying a 3d printer to print nylon that is strongly bonded. Having heaps of problems but am getting there, nozzle wear is the next problem I have to solve.

Did anybody see the recent article going around about the 3D printed aircraft. parts of my designed aircraft will have printed parts in load bearing areas. Has anybody on this site made load bearing parts for aircraft? If so what experiences have you had?

It certainly went 270degrees. Yes you could counteract it if you could discover the stuck brake in less than a second. Took me some time after the craft stopped. It was kinda frightening.

I would not say that tricycle gear cannot ground loop! Did it when a brake stuck on! Anything will ground loop if the resultant drag forces produce a moment offset from the centre of gravity

Just did my Class 2 with a DAME. Cost me $50 less than a basic class 2. And I can again fly at night and do aerobatics. I only had one examination, not one with an optometrist and one from a doctor. Won't do the Basic Class 2 again.

I have lived under the Lane North of you for over 35 years. I've seen quite a few aircraft coming Southbound in that Lane I also questioned it some years ago and I think the answer I got was that's an advisory Lane not compulsory that someone else might be able to confirm that. Personally I wouldn't go South in it

Around 10 years ago a group of us on the Mooney Australia web site were planning go to NZ. The guys that did the planning suggested that we would be up for a couple of grand each, singly I would expect more. A visit to their website may find the person that knows what to y.

I rented out my first aircraft, it cost me a fortune in damages cleaning etc. My Mooney was only ever flown by me when I owned it. I am so glad that I did not rent it. Same with my house when I rented it out. Only once!

No toe out will help taidraggers. Race cars use it as it responds quicker. Also consider that the C of g is in front of the wheels. A drag to the off side will pull the craft the other way correcting the off course deviation. Toe out on tricycle craft will make the off track worse. It is all in where the C of G sits. All forces produce moments about the C of G.

I believe that the toe in/out depends upon whether the craft is a tricycle or tail wheel. In a tail wheel the C of g is Infront of the wheels, this is critically stable and can lead to instability very easily. I understand that on a tail dragger toe out is better as it acts quicker and pulls the craft back to a more straight line during landing. Landing is where stability is critical, taxying can be less important and whilst annoying I think that most manufacturers look to landing characteristics. Tricycle craft have the C of g in front of the wheels, somewhat more stable arrangement for landing. It is my understanding that manufacturers will arrange toe in/out on tricycle craft so that from touchdown to relatively slow motion that the wheels are close to zero toe in/out. The toe in/out at this point of relatively low loading depends on the way the undercarriage moves with camber and caster and forward alignment during the process of undercarriage loading. I think that as you can only adjust the undercarriage alignment during stationary but light to medium loading is critical then it is trial and error, unless you have a finite element program and lots of time to calculate a variety of options, and of course springs vary so much that you would have to test the spring rate. I have no idea what your friends problem is caused by, I suspect spring geometry or an undercarriage wear problem or change from original, but if one craft behaves differently to another of the same make and model I would carefully examine the whole system including location to the frame of the craft.

Oct 15, 2018 New #48 "Geoff_H, were you referring to the Navier-Stokes equations? They have been around for years longer than you said. And incomprehensible to us poor mortals." The way I understand it the first solution of the Napier stoke equations for ships hulls was done in 1896. I think that it was a mathematical solution to the differential equations. I think, but not sure, that it was using a froude number maybe in three dimensions

The most interesting story that I was told about aviation mathematics was told in 1970 when I was at Uni. Early in the 20th Century (around 1915) aeronautical were working on the mathematics of fluid flow around a solid body, they were so proud of themselves determining all the mathematics using first principles and then published their research only to be informed by naval architects that they had developed the mathematics 20 years before. L ack of communications!