Area-51

The rotax 912UL will happily idle smoothly all the way down to 1200 before gearbox starts chattering and if really well tuned 1000; my 80hp will idle at 650rpm happily all day if allowed to. The ULS manages 1500 ok as it has slightly hotter cam. In the air they both windmill down to 1500 off power at around 50kt. Had the same float problem with aircraft after purchase, idle was set at 2000 and thing just floated right down the 900m strip in ground effect; handed controls over to more experienced right seat and was not an issue.

Higher nose up attitude while above the stall speed also helps on round out but requires sufficient experience and practice of flying power on stalls at safe altitude beforehand.

On 17/07/2023 at 5:56 PM, BrendAn said:

one of the most comfortable cars i ever had was an old renault, can't remember what the model name was. had a 1.8 lt motor and 4 speed on the tree. softest ride and the bucket seats layed flat for sleeping.

That would of been the renault 18; yes 15,21 also a great car; better still and best all-round car ever experienced has been the peugeot fuel injected 404gt; thing did 180kmh effortlessly and felt like it just glided silently over rough outback roads; handled really well and was also amazing on fuel

1 hour ago, onetrack said:

If every Chinese person demanded a T-bone steak for dinner, I doubt whether the entire worlds population of cattle would be enough to satisfy the demand. Thus, they have to have a diet that is low on meat levels.

 

Interestingly, an Elmore-based gent who runs an agricultural business that includes an auction house and a web platform for the sale and trading of agricultural items - and who sends out a nightly missive with his recent thoughts and experiences - advised last week that his Australian-based Indian website builder had temporarily re-located to India around 3-4 months ago.

 

He had originally planned to return to Australia after several months - but then in recent days, he advised the ag business gent, that he had changed his plans, and was now intending to reside full-time in India.

 

The reasons he gave, were -

1. The cost of living in India was vastly lower than Australia. He claimed he could get enough food to keep him satisfied for a week for $10. No doubt, meat was not a major constituent in his diet for that kind of money.

2. He stated that good quality, full internet access was around $4 a month. Compare that to Australian internet and telecommunications prices.

3. He stated that the development and money-making opportunities were vastly greater for him in India (I trust that didn't include scam-organisation money-making schemes), and that he could progress far more quickly as regards wealth and position in India, than he ever could in Australia.

No doubt the sheer size of the market in India is the major reason why he sees greater opportunity there - but there is a general lack of understanding in the rest of the world, as to how fast India is developing in many areas.

I guess family, cultural, and relationship ties could also have played a big part in this gents decision to return to the land of his birth - but the factors he mentioned are obviously also important factors.

There is a general lack of knowledge within western countries as to how fast and productive the rest of the world really is. The default view on every occasion we are presented by the media in the west is that this rate of development is a "threat to national security". Then low and behold a conflict will break out and the chances of further development destroyed. Seems to happen very often; most odd; most odd 🤔

3 minutes ago, spacesailor said:

But ! .

No milk , for your tea and mostly no sugar. 

 And not a lot of meat . That we Australians enjoy .

spacesailor

This is true; that's why westerners have such a challenging time roaming around the planet; they expect too much will be the same as it is at home 😊

25 minutes ago, onetrack said:

Area-51 - You're off the hook, I think pmccarthy was referring to a certain contributor who is based in China, and who not only tried to convince us he can personally and solely design and produce a brand new all-metal ultralight design for around $30K - but he always regales us with his stories of how fabulous life is in China, how dirt cheap everything is (including factories that are rent-free for years), how China poses zero threat to Australia, and how the media feed us garbage on the true situation within China!

Well he might be right on the last point, but I believe all the rest of his stories can be taken with a grain of salt!

 

You probably need to go live in China full time to fulfill your desires as regards the substantial personal embellishments. However, I'd suggest having photos of the local Party Secretary in bed with his secretary will help you achieve that aim! - and just don't get rich enough, or powerful enough, to pose a threat to Xi Jinping, and you'll do very nicely!

Ok, thanks for the pre

mission briefing 😊

China is actually a great place to experience; great food great people. It is not one single culture but a basket of hundreds. Like anywhere you should know the local rules and customs, be polite and respectful and a great time will be had.

31 minutes ago, facthunter said:

I think screwed in valve seats are long gone. It generally didn't work in the exhaust seat situation. FIT and appropriate metals are the deal now. You certainly don't want them dislodging and if they come loose they COOK due lack of heat transfer and can shrink themselves further. . The advantage of manually adjusted valve clearances is you get an indication of this happening. With hydraulic lifters it's masked.  Nev

Agree

On 21/08/2015 at 5:40 PM, Bruce Tuncks said:

Not what I expected.. the exhaust valve seat had come out and was only held there by the valve. No wonder the compression was zero.

 

I wonder why it came out. The main force is combustion pressure on the valve face, and this force is keeping the seat in.

 

There was no other obvious damage, and the engine never runs hot. It was cleaner inside than I thought.

 

 

 

Valve seats will only fall out in operation due to the mitigating factors at the moment they are installed; most likely insufficient temperature differential clearance factor between cylinder head and valve seat. It is a more common scenario than you might think and can affect any engine employing this method, not unique to just jabiru.

As long as there have been valve seat inserts in alloy heads there has been this scenario. Some have an added threaded screw in application to deal with this.

boils down to manufacturing tolerances and QA standards to maintain and deliver those.

Overheating can also lead to this scenario.

On 29/06/2023 at 8:16 PM, pmccarthy said:

Someone who popped up on this site again a couple of days ago once strung us along for months, perhaps it was years, with a new engine he was developing. Did the same with a plane. It pays to be skeptical.

It was not me, but I declare that if people wish to embellish me with a few bags of cash, bullion, and high grade plutonium first then I may give it some thought over a plate of fresh donuts before disappearing back into the ether!!! 😃 hurry, opportunity ends soon!!!! 🍩

Watch the Right Prop rpm fluctuating afterwards; expensive badness; big fat invoice 😊

2 hours ago, MattP said:

~2000 FPM is about the ROD at best glide in a PA28 isn't it 😇 At least it makes forced landing practice easy. 76KIAS - look right down, we're not going anywhere else 🙂!  

Excellent demonstration here 😃

It's electric right? Everyone will ask if its electric because there is no propeller; like the big planes... 🤦🏻‍♂️🤷🏼‍♂️

Read a book?? I need to get one of those autopilot thingymajigs 😃

What about a straight NPSM tap and converting to a banjo fitting; more choices when it comes to dealing with tight spaces.

18 minutes ago, turboplanner said:

The hardest circuits I've found are country strips with one other aircraft in the circuit out of sight and unclear radio transmissions.

This is a challenging and anxious situation.

My personal experiences in similar scenarios at non-controlled airfields along with feedback afterwards from extremely experienced pilots.

The other aircraft may provide a very incorrect position report. I have joined circuit downwind with another aircraft clearly transmitting they were entering, backtracking, lining up and rolling on the opposing runway with no aircraft to be seen on the strip the entire time and no response to four repeated queries of their position until I called late final with a very heightened preparedness to bank hard right and power on, only to see them 50m off my port 10 o'clock at equal 150' flying the opposite direction in a twin. This was a new and very unsettling experience.

Advice received for above was: "If the other aircraft is not visual where they say they are, request they "CallSign" confirm they "are" where they say they are and to acknowledge your request", and be prepared to exit the circuit immediately if you believe it is required.

Runway numbers can be misleading if either aircraft has them perceived in reverse. (I have done this, and safely exited the circuit as soon as I realised the loss of situational awareness early in the circuit).

If one aircraft is familiar then that's still 50% chance of something going pear shaped. Get familiar, and if the other aircraft is clearly not situationally aligned then use the radio to advise; that's what the radio is there for.

The radio is not there to abuse other aircraft in flight for making an error. You can do that later on the ground when it's safe to do so if you feel, or submit an incident report.

Primary objective is to fly the plane in a safe and responsible manner.

Learn from every flight.

Its all relative; either throw more fuel out through the exhaust valve using a big bore lug engine; or throw less out using a small bore high speed reduction geared engine.

Forget any reference to horsepower; the only useable comparative data set is "Torque" delivered at the propeller flange at RPM. Nothing wrong with running a gearbox; been done successfully for past 150 years along with pulse absorbing devices. The only difference between then and now is Material's Technology.

X horsepower (derived from torque and rpm formula) = X btu's regardless of capacity. 
 

X btu's = Fuel + Air @ X ratio / time

3 hours ago, facthunter said:

Most long radials are a disaster. for reliability. Crankshaft is their weak spot. They'd have a heap of Prohibited RPM's to avoid because of the rotating masses .  Stick to single row if you can for small stuff. Some of the couplings are pinch bolts and radials can have dynamic counterweight Damping. That is why a lot of them make horrible mechanical noises when starting or idling slowly. Nev

Bose A20; everything sounds awesome! 😀

Check out Speedflow or Morosso catalogues for off the shelf AN manifold blocks; might be something in T6 ready to bolt up

😀😀👏👏👏

6 hours ago, facthunter said:

Pressed up  cranks are $#!t . They are already loaded up (strained) before they take any more load due to dynamics  and torsion. There are specific runout test for prop strikes. Let's just assume the possibility of than not being done and the engine continuing in service while out of alignment.  Nev

Rotax Heavy Maintenance, SEC 72-00-00, Pg23 - Pg25, Propeller Shock Load, Inspection Crankshaft Distortion.

I don't understand why anyone is even debating this subject. The engines are cheap with unknown reliability. So just buy and install two 🤷🏼‍♂️

So today during a check flight the AvTraffic OzRunways solution was given another run. For now it is an immediate stop gap solution, and fully agree, it is not able to supersede or replace the accuracy of realtime ADSB live signal observation equipment, or Visual when proficiently scanning the circuit in VFR.

The OzRunways screen was showing a Jetstar RPT on departure climb and there was visual on the aircraft tracking perpendicular also; so it was a good opportunity to observe actual Latency. The Jetstar RPT was also displaying both an AvTraffic ADSB and OzRunways bubble simultaneously.

The observed positional Latency was about 10 seconds.

Eventually the AvTraffic solution will be replaced by a Uavionix Ping or similar real time ADSB-IN solution.

49 minutes ago, aro said:

Anywhere between a few seconds and about a minute, at which point traffic disappears. At 90 knots, 5 second latency is a position error of over 200m - for each aircraft.

 

Traffic displays are always showing you the situation from a time in the past. In this collision, each aircraft would have seen the other aircraft as behind them on a traffic display - not a collision course. How far behind? That depends, it's impossible to know. The only time you can be sure is if you are passing behind displayed traffic. Even then it becomes difficult if the other aircraft e.g. turns.

 

I use a traffic display, they're great, but the most important skill is knowing when you need to be looking out the window and managing separation visually. Anything closer than about 1 mile, you need to separate visually and should be worried if you can't see them.

Correct, a pilot in command always needs to continue using the primary flight instrument of the "windscreen" to maintain visual awareness around the aircraft at all times.

The other query regarding lack of "time stamp" on OzRunways traffic, again, from the app Developers of both AvTraffic and OzRunways, its a few seconds.

After watching a Youtube video of a fatal WX in the US due to Latency of a few minutes at the user end it prompted me to ask both app developers what their latency was for Traffic. OzRunways had that data published already, AvTraffic updated their FAQ immediately upon presentation of my  question being asked.

Onscreen Traffic is a great tool if used affectively within its limitations. It allows a pilot to see approaching aircraft at a radius between 1-80nm. For the type of flying I do 8nm works well and provides ample time to divert and monitor. I do no use it in the circuit.

17 hours ago, RFguy said:

No excuse now not to have ADSB TCAS.

I'm muttering about doing somethhing, have been experimenting with my zero spare time on using multiple basic GPS receivers to get a good position fix with distributed antennas, since the SkyEcho GPS position fixes can be terribly poor if they dont have a good view of the sky,

SKyecho can be improved-  Certainly worthwhile also doing an active dual antenna >> skyecho adaptor- needs two patch antennas on each side of the aircraft that can see out the window, and uses a basic RF combiner (a $5 tv-sat one works) , and a 3d printed cosy sits over the top of the skyecho GPS antenna and couples the combined signals into the skyecho GPS antenna. That works OK. Needed to remember how to use my 3d printer...  needs to be a metalized plastic because needs to shield the re-radiating antenna so the aux antennas dont feedback. 

 

but standalone ADSB-TCAS wuld be triple GPS , triple antenna , to use multiple low cost cheap looks at different areas of the sky. avoids RAaus aircraft havign to put GPS-35 antenna in the top of their aircraft skin.  just take average of the fix works OK by various literature (been done many times) .  Step up from that is use a couple of high performance GPS receivers and use raw data from each combined in a central CPU to produce a high performance fix from the raw data from each antenna (IE you get distance and direction for each satellite from the Nth receiver, and use the combined set to produce the fix externally. There's a few ways to generate sanity checks which is well covered in literature. 

 

Target is 10m accuracy in XY and Z.  Good Z axis requires some sats overhead. X and Y need low angle sats distributed around the azimuth.

anyone not having ADSB in their aircraft , which includes the flying school aircraft  I will treat as persona non gratia . IE. "XYZ do you mind if we  backtrack with you down to the end of 33 ?" " NO , I do mind." . what happened at YCWR the other day is BS and it's not been taken seriously.

 

After one more recent near miss have upgraded the situational awareness by taking out a paid subscription with AvTraffic ADSB in, which now allows that data to be overlaid onto OzRunways' screen (so no longer need to switch between apps and miss critical information); and its paid dividends. The first flight afterward saw almost the exact same scenario with the very same other aircraft, however this time was able to see the situation unfolding well in advance, so simply turned away.

A second dedicated wifi slave screen for AvTraffic will be installed to add additional layer of situational proximity visual and audio warning cues.

Cockpit workload has been reduced.

The positional receive/transmit latency on both app servers is a few seconds, and works great providing there is cellular signal reception.

👏👏👏👏 yippydooo, join the club

Looks like the SR23 will be arriving some time around spring.

How did the following aircraft on final for touch n go not see there was an aircraft already on the runway?