Harthy

Thruster Hi Rich, How is the Thruster going? The supressor is an installation needed when a Powermate regulator (Powermate instructions)is fitted to the engine. This is to stop an RPM reading drop on one of the mags when doing a mag check. It does not do anything to the engine RPM, just the reading on the tacho. without the supressor the tacho would indicate a large drop on one mag and little on the other with no noticable difference in actual engine RPM between the two. But also by chance it greatly reduced ignition static in the radio. Hope all is going well. Brett

David, Have you got the formulae, it would be useful information to have. Harthy

I think when the % is calculated you have to take into account that RPM range is from 900 RPM (or what ever the recomended idle speed is) to 3300RPM, not 0 to 3300. So calculate 75% of 2400 which is RPM range, and add that to your 900 idle RPM and come up with your 75% power rating. Hope this will help out. Harthy

I also took delivery of a J120 in mid March, This is a fantastic machine. After doing 300 hours in a Thruster it is a piece of cake to fly and land, and the Thruster is good to fly. I applied for permission to fit a VSI, which finishes it off well. After 25 hours I was getting 13.5 litres /hour fuel usage, at 100kts doing 2800rpm. Engine temps are great, even when it was new and not run in. You can not beat this aircraft for value for money. I think it will make the competitors sit up and look. It has a new low profile fuel tank whick makes luggage storage easier. The service manal also quotes that up to 10% ethanol fuel can be used, so the fuel tank sealing agent must be different to the other models. GREAT AIRCRAFT JABIRU!!! Harthy

Most of the older cars on the road with distributors have variable ignition advance. Usually machanical and vacuum advance. These engines were set up with 4 to 10 degrees advance at idle depending on type, and as the engine speed is increased the ignition timing becomes more advanced usually up to 25 to 35 degrees at full throttle. In high performance engines that produce high revs, they require more advance and can be up to 45 to 50 degrees. This is needed because as the engine speed increases the piston will travel further in the time it takes for combustion to occur. So if the timing were to stay constant, at high revs the piston could very well be moving down the cylinder when complete combustion occurs and therefore you would loose power. Set timing engine are set up for the best ignition timing to suit there normal operating speeds were they will get there best efficiency for the use that they were set up for. So it is unfair to compare a motor bike or car engine to an aircraft engine as there operating parameters are totally different. I am not familiar with the Jabiru engine, but I think it has fixed timing (less to go wrong). With the mogas topic. It is a number of things that have been discussed in this thread that determine the type and octane of fuel that is needed for an engine. So because engines are different, and are used in different applications they will need different settings. I am sure Jabiru in their production process have looked at all of these variables and have set the engines up to best suit there needs. They say Avgas or Mogas above 95. Then that is what is needed. Harthy

Jabiru 2200 engines ignition run at 25 degrees BTDC. This also has an effect on the combustion process. Low octane fuels burn faster and more uncontrolled then higher octane fuels. So if you were to run 91 unleaded in an advanced engine and because of it volatility, the fuel starts to burn when the spark occurs. and the fuel suddenly erupts or ignites and will obtain complete combustion before it reaches TDC. This will give you your pinging or detonation. High octane fuels burn in a more controlled manor which delays the combustion process and you don't have the problem of pinging engines. High compression influences the combustion process and this is also controlled by high octane fuels with thier more controlled burning rates. There is a term called Thermal Efficency. This is the percentage of energy produced from the burming fuel that is used for useful work (turning over the engine and driving the prop or vehicle). In a petrol engine only about 25% to 30% of fuel energy is used, the rest of it is absorbed into the cooling system and goes out the exhaust system. So now if your engines combustion occurs early because of advanced ignition timing and is trying to turn your engine backwards so to speak. The heat energy then doesn't go into turning the engine in the right direction easily and is then absorbed into the engine and cooling system, which gives you your higher engine temps. This is probably why Jabiru recommend 95 or higher octane fuel if you decide to use mogas. I hope this makes sense. Harthy

Lead in fuel provides a couple of functions: -It provides lubrication for valve seats and stems and -It prevents or reduces detonation in HIGH compression engines Jabiru engines run between 8:1 and 8.5:1 compression ratio's, this is not classed as high compression. Combustion chamber design also has a hugh influence on on the combustion process which will also determine what fuel is required for the engine. Alot of cars on the road today run around 10:1 compression, some of these needing Premium and some will run very well on 91 unleaded fuel. This is all to do with combustion chamber design. Now onto lubrication. With very few if any exceptions, all of our new cars these days have aluminium or should I say alloy cylinder heads. For them to operate without damaging the heads, they require hardened valve set inserts (stelite) valve guides and appropriate valves to match. These in most cases last very well, and are all operating without lead in the fuel for lubrication. Jabiru cylinder heads are aluminium and there fore will have valve set inserts. I know of a Pawnee used as a tug for gliders. It has been running on unleaded and 10% avgas for years with out any problems. maybe an option for Jabiru's running on mogas The lead in fuel also causes more combustion chamber deposits which can in time reduce engine performance. Unleaded fueled engines if tuned correctly, generally run cleaner. This is all just a bit of food for thought. Harthy

Thruster Hi Sain, I know you said you were after a TST Thruster. But I have a Gemini that is as good as a TST (SEE THRUSTER IN THE FOR SALE SECTION). It has doors that are removeble and a T300 pod. I have not needed to remove the doors yet even with the Queensland summers. It has good air vents to cover the hot days. It even has a music input that might also keep the other half happy. All the details are in the for sale section, but if you need any more, just let me know. You can also talk to Tony from TOSG about this aircraft. IT IS A GOOD ONE. I want $15000, but that can be discussed You can call me on 0427 872019 Harthy;)

Phone connection There is a way, Most mobile phones come with a personal hands free. If you go to your local electronics shop and purshase a 3.5 mm plug and socket. You can then cut the wire on the hands free after the plug that goes into your phone and before the answer button. Join the plug and socket into the lead (you will need a multi metre to connect the right wires). Then just plug it into your radio for use in your plane, and join it back up to use the hands free. Also sometimes you can get none genuine hands free very cheap for mobiles. Just cut the lead and join a 3.5mm pug or socket on, and you have a permanent harness. Hope this will help Harthy

Spark plug leads Hi Sean, Another way that works very well also if you have dual spark plugs, is to tie a zip tie around the pair of plug caps and pull up firm. This will ensure they will not come off and it also stops them from vibrating on the plug tip. Harthy

Parts Hi Jeremy, How much do you want for the brakes, and do you want to sell the main springs Thanks Brett

I also purchased one of those Super Cheap Auto LED torches. They are fantastic, durable and cheap.

Hi, I also have just installed a PA-200 intercom. Iam also having problems with a poor transmission of signal, but also have a great receiving signal. I would like to talk to you about your problem to see if it is similar to mine. People can hear me but it is not clear or strong. I have a Vertex VXA-150 radio which again has nearly the same specifications as the Icom 22

Gidday, Wayne Fisher at Lismore is the only place in Australia that will make Thruster wing skins (Spectrum Aviation). You have to send one of the old skins with any adjustments you require, to him. Hope this of help Harthy