pluessy

It was mainly on the rotary engines (Gnome Monosoupape), they had no variable throttle valve, only minimal control on the valves and cutting the ignition either all or some cylinders. This resulted in the typical engine noise of engine off - engine on when coming in to land (same while starting up/idling/taxiing). https://en.wikipedia.org/wiki/Gnome_Monosoupape

The piston & diaphragm don't move unless the throttle has moved or the engine rpm changed. The piston has a very close fit with the guide tube and that captured volume acts as a damper. The passage of the vacuum port to lift the piston is also very small to reduce or just about eliminate the pressure fluctuations and piston movements. SU and Stromberg CV carbys have an oil-filled guide tube acting as a damper, mainly to reduce the movement when opening the throttle (lack of oil is noticeable by a flat spot when quickly opeing the throttle).

I met Helmut (the owner) a 5-6 years ago when I was looking at the Terrier. I didn't like the way you had to climb over the gear leg and squeeze through the door to get into the seat. At that time, he was talking about out-sourcing the fibreglass work to China. He still had all the moulds for the components at his shed/factory. Not sure what happened since then.

My Tecnam has a very small overflow bottle (200ml) and I get a 10-15mm level difference between summer and winter (engine at ambient, temp around 20deg different). Very important to know your cold (ambient) level. Older 912s don't have the "window" so if in doubt, you need to remove the radiator cap to ensure the coolant level is at the neck. The fluctuating gauge reading could indicate an air lock/bubble, faulty wiring or sensors usually result in fast movements of the gauge. Being an EMS, that will depend on the dampening factors.

Thought the same. They really hit hard on the "where is the justification" which is my main gripe. No data at all from ASA to justify any change at this stage. The survey from RA-Aus might have shown them where our position is and they have repsonded to ASA accordingly.

It depends how you value the 3% of lost power. If it is non-measurable in flight performance: no. If it is making a difference, maybe yes.

With all of this talk about getting a transponder to be able to use class E, what about some small aircraft (single seaters) with very limited panel space! I will not be able to fit a transponder in my panel/cockpit that is reachable in flight. And that is the incomplete panel, still need the fuel level tube and a few switches installed. I will have to crawl around the Atherton Tableland like in the old days with the limit of 500'!

I did get a response to my question: we are working on it! there is a very rough outline in one of their presentations, showing the “J-curve”, which is roughly where the lower limits would be applied.

If you read between the lines of this proposal, you see that they are dividing the class G airpsace into 3 catergories: low, medium and high density: As part of this program, Airservices is proposing to lower the base of Class E airspace to 1,500ft (AGL) in medium and high density enroute airspace between Cairns and Melbourne in December 2021. It is not the whole area. More than likely, it will be some decent areas around every airport with RPT and other busy airports and low-level transit zones. Without Airservices providing a map, we simply don't know how much it will affect us (with no transponder).

I have asked the question on the Air Services website re the maps. This proposal is useless without maps showing what "their" perceived medium and high density airspaces look like.

Oil temp is just an indicator for the temperature of the bottom end, CHT is the top end. If you start a cold engine and go to full power, the engine wil warm up unevenly (cylinder head and barrels warm up nearly instantly under full power) while the crank case is still cold. The different temperatures lead to different expansion of the components and many joints will be subject to minute movements. Over time, this will lead to oil leaks. VW cars were quite well know for this. Drivers who gave the engine time to warm up had clean engines, the drivers who jumped in and floored it had oil leaks from the barrel base and case. Same for the Alfa Romeo all alu engines. Once warm, you couldn't kill them but don't try a cold start and then full power.

I'm also just the messenger🙂

FYI, Pete Plumb (O-100 creator) has passed away a few months ago. The O-100 project might continue if there is a suitable buyer for the IP and tooling/processes. 1/2 VW output ranges from 28hp (840cm3) to 45hp (1200cm3) and weigh arounf 39kg (single magneto, direct drive, without electric start and alternator) to 47kg (direct drive, dual ingition, starter & alternator) So, if you are looking for an alternative for the 1/2 VW, there is very little out there in that hp range and weight. HKS 700E (55-60hp), Verner JCV-360 (35hp), Hexadyne P60 (60hp), Jabiru 1600 (56hp) and a few more have all gone down the gurgler. The Kiwi design Aviator HFA seems at a standstill since 2015. The few options in the 4-stroke 25-40hp range are converted industrial V-twins, either direct drive or with re-drive. There are a couple available complete from Europe, primarily designed for powered chutes and hovercrafts.

The problem with disposable batteries is that the manufacturer doesn’t have to disclose the battery capacity. So you have no means of comparing batteries based on $/mAh. The other factor is when they start to leak and wreck your appliance/instrument. I lost many because I forgot to remove the batteries before putting them away.

You really need all 3, filter, magplug (if fitted) and oil sample to get the full picture: the filter and mag plug show the accumulation of the wear over the time frame since the last change/clean oil samples are a snapshot at the time of taking the sample, they are subject to variations due to incorrect sample taking processes The oil sample results are also limited in the size of the particles that are detected. All elemental analysis (Fe, Cr, Al, Si etc) is limited to about 8 micron in size. The PQ is ferrous material in the 10-200micron range. All the bigger stuff is not reported unless it is visible in the sample. The filter catches everything bigger than about 10-20micron (chewed-up O-rings, piston pin plugs, brass thrust washers etc) and the mag plug catches the magnetic particles that are floating past (more important in engines with gearboxes). They are like an insurance, you hope that you never see anything but you will be glad you checked when you do see stuff. Oil analysis, filter inspection and mag plugs can only detect failures and abnormal conditions if they happen over time. A rod bolt failure, dropped valve, conrod/bearing failure etc cannot be predicted with this type of condition monitoring, unless it is preceeded by abnormal running conditions that do show up in oil sample results (excessive oil temps, fuel dilution). The one value of the oil sample is the oil condition indicators. The ALS report is pretty poor in that respect, there are very few oil condition indicators (only fuel and viscosity). I like to see the viscosity at 40 and 100deg C (standard for engine oils is 100, not 40), the oxidation, nitration and sulphation. The ALS report also doesn't contain any of the additive package elements (Ca, K, Mo, Mg, Zn, B). Additives can change from batch to batch or over time, potentially causing unintended results in some engines (leaching of Cu/Al from oil coolers is a common problem). Or show an incorrect oil used. I'm using KOWA, same price, twice the results: Query.pdf

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.