walrus

Universities and colleges are regular easy targets for lawyers because academics, while absolutely scrupulous about research ethics, are brainless commercially..

Yes, a constant speed prop may turn at specified rpm. It may also indicate full power MP and be sick as a dog. That is why you MUST check That you have full power FUEL FLOW. Revs + MP +Fuel Flow are needed to confirm full power.

I use a lithium phosphate battery for three reasons 1. Weight, it saves 10 lb. Using the old $100/lb. rule it’s good value. 2. I get very low self discharge and I can fit a battery that meets the Rotax 912 iS minimum capacity of around 30 min if I lose both alternators. 3. The weight saving nicely offsets the CS prop extra weight. 4 This model is approved by Rotax- it has dual BMSs.

Sorry Skip, old news - 2017. Still waiting. What we need is energy density per unit weight as well.

1. You can buy new drive lugs from Bert Flood. 2. The lugs are a medium interference fit and aren't pressed in but pulled in when you tighten the extension bolts. The surfaces need to be clean and dry, then apply a little duralac to the lug to prevent corrosion. 3. To remove the old drive lugs, use a suitable M8 machine screw and a washer and tube arrangement to pull them out from the rear, its not rocket science, There is no hammering or brute force involved.

What does the propeller manual say? As far as regulations are concerned you require"approved data". That is a hierarchy starting with manufacturers instructions followed by engine manual, airframe manufacturer, POH, etc. on downwards to AC43-13b. Internet website comments don't necessarily have any credibility. Having said that, my two cents worth: DO NOT over specify bolt strength because at the high strength end you may be sacrificing fatigue resistance for unnecessary tensile strength. That means your bolts may fail be cracking. My understanding from the rotax owners website is that a grade 8.8 metric bolt is fine.

Be careful! An M8 grade 8.8 bolt should be just fine. There is something else going on. Your torque wrench sounds dodgy. ‘’Furthermore, if you over specify the bolts to a higher grade, you may lose fatigue strength.

Yes, sorry I didn’t make myself clear, it is a maintenance problem that happens in humid air on the ground and makes itself known in my experience on rotation at takeoff. It happens because the filter/coalesced is dirty or torn or the drain is plugged. The picture, description and diagram show an old B737 unit - note the filter indicator on the unit. It indicates when the unit should be serviced.. ‘’The video shows an extreme case of cabin rain. It’s common under tropical conditions. We had it last month out of SGN.

youtube video;

Here is a schematic of where it happens http://www.b737.org.uk/airconditioning.htm#Water_Separator

P.S. Cabin rain generally happens on rotation. Last experienced by me in an A350 or B787 out of Ho Chi Minh (SGN) as a passenger last month. ‘Source: 6 years of analyzing reported defects in b727, 737, 767. - it still happens: “miss, there is water dripping on my head”. ‘’Solution: towels and free champagne followed by unplugging drain mast during nightly maintenance.

It happens on the ground in high humidity air - when it’s cooled you get fog. Not sure what the latest filter is. They used to be nylon fabric bags in any case the drains get blocked with crud and water enters the ducting. It generally happens on takeoff. it doesn’t happen at altitude for the reasons you mentioned.

There may also be an ill advised push to write more regulations…. There was a similar movement in marine circles once to classify vessels according to size and equipment and then to limit their voyaging according to weather and sea state. It failed because of that same problem - reducing the accountability of the skipper. ‘’What is good sense in a Tiger Moth is not necessarily safe in a 150 knot RV what’sit and vice versa. Where I live, there WAS a very brief (maybe one and a half hour) window between fronts where said RV rocket could have braved some turbulence and got away VFR and headed North at altitude to better weather at warp speed but for us Jabiru types this wasn’t possible. We are too slow. ‘’It may be that the victim saw that same window….

The water is called “cabin rain” and it’s common. The fresh, pressurized cabin air is cooled below its dew point. There are filter/coalescor units in the “roof” to strain out the resulting fog, sometimes the drains get blocked and….water comes out through the air vents - cabin rain.

This subject is not amenable to hearsay or personal convictions, period. ‘’There is an old and rigorous method of determining if there is an increase or decrease in safety levels over time; that method is called statistical process control. It was developed at least as early as WWI to assure the quality of safety sensitive products such as explosives and munitions and is based on straight forward and well understood mathematics. ‘’What is required is either an estimate or actual activity (eg. a9hours flown, number of flights). An estimate or actual numbers of accidents and/or incidents over time, in other words a history. ‘’From these numbers an average and standard deviation are calculated. We can then apply the normal distribution and calculate the three sigma limits for the distribution of incidents and accidents. This is the computed number within which 99.95%(im getting old) of all statistics will fall. That may be for example, 6 accidents per quarter plus or minus three. It is only after there have been 9 (6 + 3) accidents can we say Statistically that we can bev99% sure that something has changed. ‘’Of course there is more to it than this but you get my drift. I’m sure RAA know this and in any case ATSB can advise them on design and computation of the relevant data.. ‘’In other words, we don’t know if four fatals are significant or not without mathematical analysis of our accident history; we just do not know. ‘’There is therefore no sense in getting knickers in a knot about the overall state of the pilot population just yet. ‘Having said that, if poor weather decision making appears to be a common factor in a relatively large number of incidents (statistics again) then it is possible to test that hypothesis (maths again) by developing a questionnaire, taking a sample of RAA, PPL and commercial pilots and testing their skills. The results of such an exercise then allows RAA and CASA, advised by ATSB, to change the syllabus and training on the basis of fact, not guesswork. ‘’Having done that - changed the training, you would then watch for a change in quarterly (or annual, or monthly) statistics (mean and standard deviation) to determine if your training was effective. ‘’Been there and done it, It ain’t that bloody hard. (at least when you are young).

From memory the forecast included stratus to 1500, 4000m rain, ocsnl TS, and a sigmet for severe ice above 4500ft. ‘He would have been stuck in the valley heading NW and any deviation gets you killed. As for the alleged destination - Wollongong, that would be legally impossible in terms of remaining VFR over the Snowys, plus the freezing level was. below LSALT. ‘’Where did he get his weather info and how skilled was he in interpreting it?

All that is true Onetrack. However, if you require, inspect and pay for quality, the Chinese will produce it.

Flightradar24 indicates an aircraft is still searching this morning.

Oh dear.....................

Onetrack, I'm sorry but No. 1. The Chinese are capable of better quality than the Europeans but you have to pay for it. If Chinese quality as supplied by Bunnings, etc. is poor, then that is what we asked for and accepted. Our family company had a 35 year trading history with China. 2. Reverse engineering isnt that hard a far as dimensions go. All you need is a Ziess coordinate measuring machine and sufficient samples. If anything, copies often have tighter tolerances and better materials exactly because you don't know the thinking and don't know where you can relax the specs. 3. The biggest IP thieves are Israel and the USA. Asian countries are a poor third (amateurish) - again, I speak from experience. 4. The typical emerging industry starts by copying. Once that is mastered, they have to do R&D like the rest. They will probably destroy Rotax with better, cheaper products. I want a 915 clone for $10K 🙂

The weather today in North Eastern Victoria has been putrid.

The weather today in North Eastern Victoria has been putrid.

This morning (Thursday) is my latest fuelling, packing and checking operation but its a No Go. Windy.com suggests I might have a window to go North on Friday morning early with not too bad a headwind component, but Sunday return is not possible. We are talking about dodging fronts with moderate rain, snow, Ice and even TS - don't even think about it.

Windy indicates slight improvement for Fridayas at Wed am.

Windy.com says forget it if based in Victoria - rain, snow thunderstorm activity and 15 knot + headwinds. I’ve. been stuck in Dubbo for three days earlier this year and the western plains zoo has lost its charms. I did register and pay but unfortunately I’m a no show. I guess it’s doable from the North in something fast but from Victoria it’s a no go for me as at this moment.