Mike Borgelt

Get a TJ-100 turbine as on the Sonex Jet. Has a real oil system. All the other small jets mix the jet oil in the fuel. Fine for self launch gliders but for a real jet aircraft use the TJ-100 unless you want two engines. Two TJ-100s are pretty expensive. How about a Hawker Sea Hawk in the same concept? hawker sea hawk - Google Search Pretty aircraft. Original was single engine Rolls Royce Nene but two small engines would fit in the wing roots with plenty of space for fuel. Roughly the equivalent of the Grumman Panther.

Really bad idea on low speed draggy low wing loading ultralights. Makes sense on self launch or sustainer sailplanes, although if you want to fly very far in the sustainer sailplane you are better off to trade weight of fuel for an extra engine. Sounds crazy but you just climb burning all the fuel, then retract engines and use the high L/D of the glider for range, otherwise you are burning fuel and not climbing). Reason it works is modern gliders have low drag at high speed (best rate of climb speed for an adequately powered glider with a thrust/weight in the 0.125 to 0.15 region is around 100KIAS giving a rate of 800 to 900 fpm) and duty cycle on the engines is low, unlike the 100% duty cycle on a powered aircraft I have a nice spreadsheet that gives performance for jet powered gliders. Rate of climb, takeoff distance etc. Would work for powered aircraft if you can get a good estimate of the speed polar and also would work for prop driven aircraft if you can figure out the static thrust and diameter of the prop. If you want a jet power plane, start by flop molding a glider cockpit, put small wings and retractable or buried landing gear on it and use a couple of the 40 Kg plus thrust engines. Do check that you have adequate single engine performance, EXPERIMENTAL Amateur built and you have a nice machine to go out into the training area and do jet aerobatics. Not a travelling airplane.

oops link : www.axsport.co.za

These guys are producing props for Jabs and Rotax and in development is the model for Lycomings. Direct drive 4 cylinder engines have only 2 power pulses per rev. Rotax have 4. Higher loads in the Lyco case.

[quote= An Important takeaway I remember is an amount of stress called the "endurance limit" ( I hope I remember this correctly ) and at that amount of stress and lower the aluminum incurs zero fatigue buildup. The presenter explained that although it may be engineering overkill .... whenever a large weight penalty is "not" incurred that it is a good idea to design structures with such low stresses that they rarely incur any cumulative fatigue. .. Not so for aluminium but can be true for mild steel. Composites are good. See here: Fatigue limit - Wikipedia

I notice most of the people here fly aircraft powered by hydrocarbon (petrol mainly) fuels, not gliders. Tells you a lot about the utility of wind and solar power for aircraft doesn't it? The maritime industry gladly gave up sails when steam became available and now sail powered boats are just for fun. Nobody ever used a windmill to grind grain if a perennial stream could be used to power a waterwheel. All of which should tell you heaps about the reliability, utility and economics of wind and solar. The only thing renewable about wind is the whirligigs themselves which need both regular and unforecast replacement which involves concrete, steel,composites and various exotic metals along with diesel fueled transport to get them on site and diesel fueled transport to inspect and maintain them. As for the bilge about reliability and flexibility, too bad about when it is nighttime and the wind isn't blowing. Oh well, it has been 500 years give or take since the Renaissance which started our rational, scientific, technological civilisation. Not a bad run. I'm sure you will all like the Third World.

A single wind turbine may not cause much of a problem but do remember that there are tip vortices off the blades. Now get an array of turbines and the right wind direction when you pull megawatts out of the air and some of the vortices align and reinforce. I'd give them about 5km clearance on the downwind side. At least. Maybe more under certain weather conditions- low inversion etc As for environmental effects, they are noisy close up and within a few kilometers with infrasound as well. US DOE did a study on this about 20 to 30 years ago and the infrasound causes problems INSIDE houses which are worse than immediately outside. This study seems to have been buried. They kill raptors and bats but the companies get a free pass while a coal or oil or gas company would be heavily fined or shut down. You'd better hope that they produce more energy over their lifetime than went into manufacturing, transporting, installing and maintaining them or your civilisation runs down. Nobody would consider putting up a wind farm (actually they are tax farms) if it wasn't for the subsidies and the fact that the RET means that the power companies MUST buy all the wind energy when it is available. Which means that the coal or gas power station must vary its output and can't make enough money to be economical as it would be happy running at close to full load 24/7. Gas plants which can't vary the load easily are combined cycle plants and are much more efficient than open cycle gas turbine plants which can. With wind you need to provide backup for the times when the wind doesn't blow. Backup can be coal, gas, nuclear, hydro, pumped hydro or batteries. Factor in that expense and the price of electricity is many times that of coal or nuclear generation. If you don't like CO2 go nuke. BTW the climate has been about what it is now for around the last 10,000 years. Sometimes warmer, sometimes colder but on a cooling trend since about 8000 years ago (know as the Holocene optimum). Check out the Greenland ice core record. 20,000 years ago where Chicago is now was under a mile of ice (probably not a bad idea actually). The level of CO2 at the end of the last ice age was getting into the range where a whole class of plants gets stressed and much lower,die. Go to 100ppm and even the plants adapted to low CO2 die. Then all the animals, including us. Now it may be feasible to go "Wind Farms + Solar Farms (PV & Mirror/molten salt) + pumped hydro & batteries" (with occasional blackouts and compulsory demand management) but any company making stuff will re-locate to other jurisdictions outside Australia where only lip service is paid to the green madness, if at all. There won't be any jobs here for you or your kids. The public service is not a wealth generator.

People. There has been NO meaningful medical reform in Australia. Zip, nada, bupkis, zero. I'm corresponding with a person with skin in the game who has done the DAME training course and have a copy of the instructions. NOTHING has changed as to medical standards or proof thereof. Sure your DAME can issue - maybe - if he or she feels like it but can choose to just kick it to CASA AVMED. CASA can still review it if they want and demand anything. The cost of registering might go down from $75 to $65. Big deal. The Basic Class 2 is just a re badged DAMPC with all the same restrictions and exclusions so any one who has ever had any kind of medical problem that came to CASA's attention will be unable to use it. In any case it has some stupid restrictions, ther e more for their own sake than for any sensible reason. No turbines? - WTF does the engine have to do with medical fitness? We have been lied to yet again by our government and its flunkies. Worse, organisations like AOPA are hailing this as "medical reform". Shows how useless they are. A campaign of rejection of this "reform" might have been good but acceptance means this will be the end of meaningful aviation medical reform in Australia for at least 20 years. I have no doubt that at some point CASA will come after glider pilots and RAAus and the GFA and RAAus will meekly roll over and sell out their "members". GFA couldn't even be bothered putting in a submission on the mdecial reform during the consultation period even though they depend on tow pilots. Some of them have already quit because they sold their powered aircraft and thought they might just do a bit of towing but with the medical and AFR it is just too much trouble and expense.

Yep, NZ has an entirely undeserved reputation for having a reasonable set of civil aviation regulations. I was there 2 and a half years ago looking to buy an aircraft to fly around for a couple of summers but found nothing suitable and I was also told that an ordinary PPL medical will set you back $700 to 900 because they require full blood tests etc etc. Their Experimental homebuilt regs are at least as restrictive as ours, maybe more so. The place is also an Air Traffic controller's paradise with controlled airspace (you will need a transponder even in Class D which they have radar for, never mind that ICAO Class D is non radar controlled airspace and controlled airports everywhere a twin turboprop regional airliner goes (most places). Pain in the rear. Navigation is no problem, when you can fly, because the weather sucks. The whole place needs to be towed 600nm north. My wife is a NZ citizen BTW. After 41 years applied for Australian citizenship but so far it has taken 9.5 months and nothing yet. I guess white, heterosexual female sporting shooter with pilot licence who has never been on welfare and has been gainfully employed the whole time is a difficult case.

Much of aviation regulation is theatre. It is there to convince politicians and the public that SOMETHING is being done. Doesn't matter whether it is effective or not or whether the industry gets destroyed. The so called self administrating bodies are no better as they depend on CASA for their operations and hence have lost the power to say NO. If some young person nowadays tells me they want to get into any kind of recreational aviation in Australia I tell them they really don't and should find something else interesting to do. Or move to the USA if at all possible.

This is about the most pathetic non reform that CASA could have dreamed up. AOPA and others were stupid enough to hail it as a breakthrough instead of condemning it. It will ensure there is no real medical reform in the next 25 years unlike what has happened in the UK and US.

Every road area subject to flooding should have in addition to water depth markers, a sign a sign that says "Are you feeling lucky, punk? Well, are you?" Might get people to think.

Regarding CASA prosecuting Ashby: You need to understand that all the government authorities involved in regulating activities properly don't have that as their primary goal. The primary goal is the survival of the organisation so that its employees maintain their pay, position, perks, pension and the power to keep it all happening. This depends on political support hence they like prosecuting high profile cases which attract media publicity to keep the politicians convinced the body is doing its job. Quite a while ago now ASIC in WA had 12000 complaints a year about cons and scams involving companies. Most were regarded as legitimate.They prosecuted 20.

"Unbelievable growth ?" More like just unbelievable. aka "FAKE NEWS".

People who think the RAAus is not CASA are deluded. It IS CASA. Bought and paid for. Operates with CASA approved manuals and doesn't do anything without CASA's approval. In business terms this could be called "Misleading and deceptive behaviour". Why would anyone expect RAAus to act on any member's behalf or for the member's benefit just because CASA has engineered a situation where you pay TWICE over for aviation regulation?

Well, the Chinese had better figure out how to completely re-cycle the batteries. This is done with the lead acid SLI batteries, quite well. IC auto pollution is only a problem in large metro areas. Over most of Australia it is inconsequential. The problem is the idiots in government will want a 100% solution where reducing the number of IC cars in cities to 10% of the present number will do fine.

"There was a big boom in RAA flying hours in 2016/2017, so it seems that the RAA have found that perfect compromise between costs and safety. I can't emphasise enough how big a break through this is in the history of GA in Australia, if not the world. I know of no organisation capable of a 80% increase in flying hours and a drop in fatal incidents." You forget to add the /sarc tag.

"Problem is a number of countries are mandating and going straight to full EV by 2050" Oh good. They had better amend the Laws of Physics while they are at it. Politicians seem to think they can do this. As for "Australians have no idea about depletion", you can leave off the last two words, Bruce.

I've got a worse story than this one but I'm sure not telling it here. The camera under the nose is a great idea, also if you operate where there are obstacles after takeoff as you usually lose sight of them when you rotate. The "plane" stupidity in this incident has nothing to do with law or MPC or anything else and please note you do not need to be a SAAA member to operate a E-AB aircraft. It is just a case of a complete cowboy operation. Take away the guy's licence and LAME ticket and bin them forever.

Lower aspect ratio means less slope to the lift curve. The extra area should mean greater restoring force per degree of sideslip angle but not as much as the extra area might make you think. Spiral stability will be lower but that usually isn't a problem. Most gliders are spirally unstable at thermalling speeds. Why would you spin it? The BD-4 was never spin tested and several hundred were built and it is one of the safest homebuilts. A few years ago on the BD-4 newsgroup this was discussed and one of the guys came up and said he's spun his lots of times. The designer then came on and said not to spin it as they they never did test it in spins.

The Queensland Health payroll system is about the worst disaster I've heard of. That should have cost a few million ended up at hundreds of millions and I'm not sure if it works. Haven't heard that anybody got fired/jailed etc. About 20 years ago a Lycoming guy gave a talk at the local aero club. When Lycoming got all computerised they ended up having to put all the people doing it in a secure area with guards to prevent the employees from getting at them.

Anyone else noticed that government websites are usually the ones that don't work as advertised, are slow and generally suck? About like the bodies that have them, I guess.

I know the crossed sticks work because I built one when I was about 14 after reading an article about boomerangs. Airfoil??? Don't need no airfoil. You might want to round the edges of the flat pieces of wood and add some weight to the tips (I used balsa for the wood). Flat plate airfoils work quite well for this purpose.

I think there was no understanding of aerodynamics involved in the invention of the boomerang. Likely someone picked up a piece of wood that happened to be the right shape and threw it and it flew. Two straight crossed pieces of wood joined together works just as well as the "boomerang" shape. Seems that didn't get "invented" back then Oh, yeah, the boomerang that comes back is useless. Better one that hits the kangaroo and stuns or kills it with its angular momentum. The roo will be gone anyway if you miss so you can walk over and retrieve the device.

A proper fire warning system and a fire suppression system are both good ideas. Most of the current motorgliders with piston engines have a fire warning light on the instrument panel. No fire suppression. Better hope it goes out when you turn off the engine and fuel. The warning system on at least one German motorglider consists of ONE thermistor at the front of the engine compartment. Really quite unsatisfactory. Nothing unique about a jet catching fire, there have been several incidents around the world where a conventional piston motorglider caught fire including one at Lake Keepit where the engine backfired on startup on the ground and the back of the ASH25M burned off. Oscar the published L/D of a Nimbus 3DM is 57 clean and 17 with the engine extended. More than a small difference. Motorgliders used to have the engines out in the breeze on a pylon. This was probably OK but over the last couple of decades the engine has been left inside the fuselage for noise reasons and only the prop and reduction drive are extended. The engine compartment in one recent German motorglider is lined with what looks like kitchen alfoil glued to the composite structure. Not much of a firewall. Obviously the idea is to not put the engine away until it is cool enough not to be a problem.This can be automated. We don't know whether Paul's engines were extended and running or retracted when the problem happened. He phoned me just before New Year for my opinion on the new batteries he was wanting to install (5 cell LiFEPO4 - the safest lithium chemistry) as the maximum voltage just off the charger was 18.0 volts and he was worried about this on the AMT jet controllers. I didn't know but will be finding out. I hope we find out which battery packs he was using. He used to use Lithium Polymer which is a REALLY BAD idea. NEVER use these in a manned aircraft. Li-ion like in your laptop isn't much better unless you use a pretty fancy management system. A laptop has plenty of computing power for that. Paul was also using propane start for his engines. A gas leak could cause a problem on startup. I'd be looking for other causes than a dribble of fuel on retraction with a still running engine. The fuel supply is via solenoid valves and electric fuel pump. When you shut the engine down the solenoid valve closes and the fuel pump stops. Really two things have to go wrong to still get fuel into the engine. There is also the engine monitor indication to say the engine has shut down and the EGT has fallen. There are a dozen or so Jonker JS1/JS3 gliders in Australia with a sustainer jet installation. These seem to be working well. They have kero start and LiFePO4 batteries. I had a good look at a JS3 a couple of weeks ago. Certainly no fire suppression and I don't know about fire warning.