pluessy

I have been taking oil samples on my Rotax 912 since I got it at 180h (engine). The initial results showed 2 problems: avgas is loading up the oil with lead, big time the oil temps were too low (lower end of the green range), visible from fuel dilution and some water I'm cutting the oil filter and keeping a section for my records, and take a picture of the mag plug at the gearbox before cleaning it. I'm trying to avoid avgas like the pest now and I have added a barrier to the oil cooler to increase the oil temp (size varies with season). Rotax recommends to run the oil temp to the top of the green at least once per flight, to evaporate water and fuel. The Bings are running rich and fuel gets into the oil. Professionally, I deal with oil samples every day, interpreting the results from the lab and preparing work instructions if actions are required. At the same time, I have removed a number of oil sample points on mining gear and replaced with a photographic record of the mag plus. Much more telling and immediate (3 compartments with oil mixing). Oil samples need to be taken at regular intervals, one-off samples have little value. It doesn't have to be every oil change, it can be every 2nd/4th or what ever is suitable. Just make it consistent and provide the lab with the correct information (critical is oil hours and oil make/type/grade). The only problem here in Aus is that no lab has the personnel familiar with aircraft engines, hence the "we can't comment".

If you have an ABN, look at data share SIM, that way you can share the data with your phone/other devices (needs to be by the same provider). Telstra is $5/month incl 100MB. I think Telstra dropped the data share SIM for personal use, they don't show anymore.

at normal fuel pressure (0.3-0.4bar), it is ~3lph and pretty steady (proportional to fuel pressure). I hardly ever look at the fuel flow meter anyway these days, I know I have 2h of flight time in each wing tank, so 1/2 tank is 1h. That leaves me with ~20lt after 4 hours. I have asked JP Instruments to consider a calibration feature where you could turn the electric pump on (engine off) and the unit would use that fuel flow as default return flow. I don't think they did that

My sender is in the line between the Facet pump and the mechanical pump (which is the longest straight line), with the return line after the mechancial pump. It is important that the return line fitting is after the mechanical pump (I think most engines have it in the 4-way joiner from the pump to the 2 carburetors). I haven't seen any installation where the sender is on the mechanical pump outlet?

2 blade vs 3 blade is comparing apples with pineapples unless you clearly specify what props are being compared. I changed a wooden 2-blade (GT) for a carbonfibre 3-blade (Bolly) and both my acceleration, climb and cruise have improved slightly (most consistent 1-2kts more speed at the same rpm and fuel burn). The carbonfibre blades are thinner and narrower than the wooden blades, off-setting the 3rd blade area and cross section. If you simply add a 3rd blade of the same thickness and planform, the result will be a less efficient prop.

Hi, the specs that I have for the Sapphire LSA Mk2 show a MTOW of 320kg for the 447 and 350kg for the 503 powered units. The empty weight for the basic 447-powered aircraft is listed as 170kg to 201kg for a fully optioned 503. These specs are from the old RA-Aus website and the then manufacturer (Steven Dumesny).

If you are still after a Bolly pitch gauge, mine is available?

Negative to the last question. The Bolly pitch tool is graduated to 1/2 degree and very difficult to read. It also suffers from friction and is unstable when holding on the prop blade (needs to be kept accurate and still in 2 axis). I spent a long time adjusting my blades when I installed my new Bolly. Now I have made a precision tool that gives me repeatable results in a few seconds flat and found over 1/2 degree of variations. Preparation work is to have accurate station markings on your blades (I use 500mm from the hub, serves also as the pull-point for the engine friction test). Then set the trailing edge of the blade level through the spirit level (bubble), record the reading on the clinometer and go to the next blade. Pull the prop very slowly and from the top blade to minimise aircraft movement (this set-up is not sensitive to aircraft movement, unlike the stick/laser method). There is a bit more work involved if you are installing a new prop as you need to calibrate the 0 line first. For checking the pitch on each prop or to change the pitch from a known position, real quick and easy.

Hi Scott, I used a small hammer and a rounded steel pin (ground it to the shape of the ball curve) to re-shape a couple of damaged ends. Then I used valve lapping compound to bed them in to their resp sockets. They are sealing properly again.

Do the 100 hourly like an annual, record it as an annual and you are good for 100h or 12 months, whichever comes first.

CASA is missing the main point: all aircraft in the same approx location MUST be on the same frequency. Listening to area is a total turn-off with the dribble from far away and high altitude aircraft making 99% of all transmissions. All I need to hear is who is doing what in a 30-50nm radius of my position.

[ATTACH=full]62004[/ATTACH] I hope you finished this installation and fitted some drip trays (heat shields) under the carburetors? What size are your oil lines? They look smaller than mine.

That's the whole problem wit this setup, there is no direct check. The only thing you can do is crank the engine with no load (spark plugs removed) until you have steady oil pressure. This way you at least know that the pump has been primed, and then hope for the best and keep an eye on the oil pressure gauge

Sorry, need to correct you here. The oil pump is fixed displacement, the only control over the volume you have is the engine rpm. You actually throw oil away when you lower the PRV pressure as a portion of the oil leaving the pump is now being returned to the pump inlet and does nothing to lubricate or cool the engine.

OK, defies logic. 45psi is 3 bar and that is well below the opening pressure of the PRV. Mine is on 4bar (5,000-5,200rpm) and changes ever so slightly with oil temp. I don't know what my relief pressure is, I have never revved the engine high enough with cold oil to see that pressure. One interesting fact with Rotax engines is that the running oil pressure actually increases with increasing oil temp. When I take off with 50deg C oil temp, the pressure is initially 3.6-3.7bar and then increases during climb to 4 bar when the oil temp reaches 80degC. This is a result of the diminishing suction line losses with decreasing viscosity, more than off-setting the increasing pressure loss in the post pump circuit.

The relief valve is supposed to stay shut to 5bar. If there are pressure fluctuations that happen below that pressure, then an oscillating relief valve is a symptom and not the cause. Changing the relief valve in this case most likely "fixed" the issue as it would have a very different harmonic frequency (different spring and different plunger mass). Jabiru has that problem with oscillating pressure relief valves when the PRV is activated (high oil pressures). The pressure spikes are splitting oil coolers! It doesn't happen at oil pressures below the relief valve setting.

To my knowledge, the oil is not affected in this application. The life of the oil is too short, 50-100h max compared to a hydraulic system (several thousands of hours). The most likely component(s) to cause cavitation (vapour) are also not oil components but fuel! When my oil temps wouldn't come up to 80-90deg C, I had over 2% of fuel dilution in the oil (most of the time it is under 1%). Cavitation is caused by a small part of the fluid experiencing a local pressure that is below the vapour point eg forming a tiny vapour bubble. Speeding up a pump that already struggles to get enough fluid supplied is not the fix. The usual remedy is the reduce the suction loss (reduce pipe length, increase dia and replace/remove fittings with low-loss versions). If that is not possible, increase the source pressure (elevated reservoir or pressurising it). I have a Tecnam P92 and Tecnam, in their wisdom, is installing the oil cooler with the inlet/outlet fittings down (contrary to Rotax installation requirement). After every oil change, I'm cranking the engine with spark plugs removed until I have steady oil pressure. When cleaning out the tank, I also drain the lines and then use a vacuum pump (oil sample pump) to bleed the suction lines and oil cooler at the oil pump inlet.

There is a general misconception that the oil pressure relief valve REGULATES the oil pressure. All it does is LIMIT the maximum pressure at the location of the relief valve. Even the Rotax manual is wrong by saying "The oil pressure from 1.5 to 5 bar (22 to 72 p.s.i.) is controlled by the pressure relief valve (8). The surplus oil returns to the oil pump rotor via the channel (9)." The relief valve can't regulate the pressure below it's opening pressure. According to the Rotax manual that would be 5bar (the operations manual says max 7bar). Below the relief valve setting, the oil pressure is a function of volume (rpm), viscosity (oil temperature), pressure loss (filter, passages) and leakage (lube oil demand from all lube points). I had originally a thermostat fitted with very poor plumbing (90deg brass elbow, 180deg bend in the hose) and lower-than-ideal pressure and pressure fluctuations. Removed the thermostat and re-hosed the suction lines and now have rock-steady 4bar at 5,000-5,200rpm and 80-90deg oil temp. Oil temp control is not with an adjustable blank in front of the oil cooler (25-40% of the area summer-winter). The Rotax engine is the only engine I know of that has the oil cooler in the suction line. Any restriction will cause pump cavitation and erratic oil pressure, the relief valve is more likely a symptom rather than the cause.

check out their history: 1400: abandoned VM 133 MK: abandoned JCV-360: abandoned

I can't compete with this sort of snow, Australia only had some mini snowfall at the start of this winter. This is on top of the highest mountain in Victoria, Mount Bogong at 1,986m (6,516'). I took off from Mount Beauty and climbed past Mount Bogong on my way back to Narrabri.

just commit yourself to 3 stubbies less in the fridge and use that free space for the glue Problem is the shipping from landing in OZ to your location.

I'm in the same boat, I have the Oratex foil but not ready yet for the covering. I did order the unmixed glue with the foil but that is now 5 years old!!! Now I'm working towards having all surfaces requiring covering completed before ordering the next lot of glue (and book some annual leave).

air intake under the prop (round hole), then flex duct to the heat muff on the exhaust muffler, from there another flex hose to the valve on the firewall (bottom left on the P92). The flap directs the hot air overboard (out the bottom) when closed and through the firewall when open. Inside are a couple of smaller flex hoses directing the warm air to the 2 vents on the instrument cover and there is a small outlet in the feet area. Pretty standard for most aircraft.

Just returned from a short trip Narrabri-Glen Innes and back. It was 1-2deg at 7,500', so the heater was on all the time. Glad I have it.

Just be aware that the required glue has a very short shelf life! It only comes in the pre-mix now and is good for max of 3 months at 25deg (Shelf-life 3 months at 25 °C (77 °F), short time (max. 24 h) allowance 30 °C (86 °F)). Don't order it in the middle of summer!