Ross

Leads I can imagine an aircraft with a busted U/C leg sitting in a pool of Avgas with two live connections to the battery under the cabin floor or very near it.

J170 vs J160 According to the POH, what is the Stall speed of each aircraft with full flaps deployed? Regards

Engines I suspect you are unlikely to get an answer to your question about a Jabiru motor without quoting the full engine number, whether mechanical or hydraulic tappets, whether it has been factory overhauled and if so what replacements for wear have been done and what upgrades if any have been fitted. Is service history of the engine available? How did it do the first 500 hours?? A bloke I know actually admitted running his motor for a kit plane without a prop or cowls in his garage for a few minutes!! I would not comment, but those are some of the questions I would need to know to get an opinion from more experienced people than I am. Regards

Thermocouples It was many years ago, about 40, in the Instrument section of the Combustion department at Australian Iron & Steel Pty. Ltd. (BHP) at Port Kembla during my brief experience in that department with little experience under the direction of experienced Instrument Fitters that we made thermocouples used around the various production furnaces such as coke ovens, ingot reheating, slab reheating, blast furnaces, open hearth furnaces etc if I remember correctly. The actual very high temperatures inside the melting furnaces such as the open hearth furnace were more difficult being measured by focusing the radiation rather than the hot gases or molten steel from inside the furnace up a tube and onto a number of small thermocouples in a circle arranged in series I think to produce a bigger voltage which was compared against a standard voltage produced by a special long life battery in the instrument. We used two wires, something like a bare inch or a bit less of each was twisted together then heated with an oxy acetylene torch until the end of the pair melted together in a small ball on the end of the pair. The size of the ball did not seem to be critical. The two wires were of Iron Constantan and Platinum after 40 years memory ago?? Platinum is worth more than Gold. Gold about $A1,219/ounce, Platinum is about $US1,600/ounce or over $US 57 million/ton Nowadays there are plenty of suppliers with thermocouples made up to suit a multiplicity of uses and range of temperatures and instruments to go with them. The instrument is really a special sensitive voltmeter calibrated in degrees C or F. There is plenty of information on the internet on the subject of thermocouples i.e. two dissimilar metal wires welded together exposed to continuous heat produces an electric voltage or current related to the temperature of the junction. There are various combinations of wire types types suited to different temperature ranges also they can be insulated with ceramics to be inserted into a metal hole in for example a carburetor body to check on icing or used bare in exhaust flues or cylinder heads. The carburetor, CHT and EGT in our RAAus aero engines are well within the range of simple thermocouples. See the following site for an introduction. There are probably many small firms and large ones involved in these types of instruments in Australia. Thermocouple - Wikipedia, the free encyclopedia I am not an expert, in fact not even up to date on what is available. Regards

I had a close look at a very nice J160 with 3300 ccs sitting up the front visiting Leeton's Brobenah airstrip last year at a fly in for a couple of days. I have a number photos if you are interested but not under the bonnet. Rod Stiff told me in a personal phone call a few years ago that the 2200 and 3300 motors share the same engine mount. If I remember correctly what was said by the pilot owner builder, it required a bit of restraint on the amount of throttle used on takeoff otherwise it tended to be rather vertical! Does it have standard J160 wings-I do not know. I would expect that it would have reduced fuel, luggage, passenger carrying capacity to be legal.

A local friend is building a Sonex kit which comes with a very nice looking fuel tank; some kind of plastic fuel tank moulded into a complex shape which looks very rugged, not fibre-glass. I have no information on it but it looks very good - the material might be worth researching. Regards

In relation to air locks in fuel lines the smaller diameter fuel lines are more likely to carry air bubbles along the line rather than allowing an air bubble to rise back to the tank in a sloping or vertical line due to the bigger effect of the meniscus in a smaller bore hose or pipe. You can see this effect in clear tubes by standing a few short lengths of them on end each of different sized diameters in a dish of fuel. The fuel will rise up the smallest diameter tube the longest distance - this will be the tube size that gives the most problems with air locks. The bad effects of friction and meniscus rapidly reduce once you get to about 1/4 inch diameter tubing or larger with petrol.

20091104 Cover fuselage door hinge recesses old style door hinges Trimmed off existing wide cover off back of door hinges brackets as it needs an excessively sized space to clear the fuselage in the fuselage hinge recess. Cut out four new covers from spare material to blank out the hinge recesses. Cut slots in the covers to suit the thickness of the door hinge brackets. With the doors in place, fitted slotted cut out covers with self tappers while checking clearance by swinging the doors. Due to sloppy hinge pins & holes, large clearance was needed to allow for door hinge bracket clearance in the slot. Once clearance is OK sanded fuselage in hinge area back to fiberglass - cleaned up sanded area of fuselage & new covers with acetone. [ATTACH]9049.vB[/ATTACH][ATTACH]9050.vB[/ATTACH] Applied "5 minute Araldite" to new covers and matching positions on fuselage, fixed with self tappers. Checked door clearance as each cover is done. Wiped off excess araldite with acetone rag. Allowing to cure Once the araldite has cured the self tappers will be removed, the holes filled, and fill applied around the covers to smooth them up. With these external covers over the hinge recesses it should be easier to reduce air flow into the cabin.

20091020 Door window polish (starboard door) The starboard door was temporarily mounted on the fuselage to facilitate handling & inspection during the window polish. The door was tied so that it could be opened & pushed in the polishing process w/o damaging the hinges. Both sides of the starboard door window was polished as done for the port door window. The photos from inside show a couple of the stages, first one is after the first liquid polish, second one half way through a wash and clean up between polishes, the third one is final polish on the inside of the window. [ATTACH]8928.vB[/ATTACH][ATTACH]8929.vB[/ATTACH][ATTACH]8930.vB[/ATTACH][ATTACH]8931.vB[/ATTACH] [ATTACH]8932.vB[/ATTACH][ATTACH]8933.vB[/ATTACH][ATTACH]8934.vB[/ATTACH][ATTACH]8935.vB[/ATTACH] The rest are some shots after some of the polish passes on the outside of the window. The reflection of the open outside garage door behind me in the bottom right hand side of the last five photos is gradually getting less of a halo around it as the polish on the window is getting better.

20091019 Door windows Polish After temporarily fitting the port door and seeing that the window that I previously "polished" looked disgusting with lots of shallow scratches and even some paint spots, I had another go at it with the "polycarbonate Rectification Kit". That was a step up from what I had been using so far. The first photo below shows most of what is in the kit. It included two sticky 5" sanding disks at 2400 and 3600 grit, and three different bottles of liquid polishing liquid together with a sticky 5" disk lambs wool applicator, and a sticky 5" sticky disk sponge applicator, a number of micro fibre cloths and a couple of flannel cloths. It also has a sticky disk holder with a spindle to allow it to be used in a normal drill chuck. I supplemented that with my battery powered drills and a 240 volt orbital sander with a 5" sticky holder. A water spray bottle from the local supermarket was a very useful addition during the polish process. [ATTACH]8896.vB[/ATTACH] The photos below show the changing clarity of the polycarbonate after successive passes with the polishing process. The back light in the middle or left of the photos is an extension trouble light in the cabin. The bright spot on the upper right of the photos is a reflection of the neon lights in the ceiling above the A/C cabin. [ATTACH]8897.vB[/ATTACH][ATTACH]8898.vB[/ATTACH][ATTACH]8899.vB[/ATTACH][ATTACH]8900.vB[/ATTACH][ATTACH]8901.vB[/ATTACH][ATTACH]8902.vB[/ATTACH][ATTACH]8903.vB[/ATTACH][ATTACH]8904.vB[/ATTACH] Each pass started with a spray with water on the polycarbonate, then the first pass was a couple of goes with the 3600 grit using the drill to hold it with each run at right angles to the previous run. Once the grit was finished the window was washed and cleaned and then sprayed with water ready for the first liquid polishes which was applied with the lambs wool applicator again at right angles for each run. That liquid polish was repeated with a wash in between polishes. The next liquid was used for another couple of polishes with the same procedure of spraying and washing in between. The last liquid polish was applied with the sticky sponge on the end of the electric drill. The gear was all washed in a light detergent and hung up inside the house to avoid dust on the micro fibre cloths. Both the inside and outside of the window was done. I spent about four hours on that window. It is not perfect but a big improvement.

Commenting on the post from Alan of FNQ. He comments on the angle of the added deflector tab under the rear of the engine. I would assume that it acts like an aerofoil section and would stall if it were attached with too great an angle to the bottom of the engine compartment. So it would probably cause turbulence there and even result in higher pressures immediately downstream of it thus reducing the airflow through the engine compartment.. So Alan's more effective added tab that is at a flatter angle than the others makes sense to me It would be interesting to know what those angles were!