RFguy

Like Nev said, if people would have their seatbelts on... idiots..... I have zero feelings for the people who got hurt on SQ while sitting in their seats without seatbelts on. I always say to the pax next to me , that it's a good idea to always wear a seatbelt whenever practical in case of explosive decompression, and give examples (pan-am, hawaiian etc). of course if you were on your way to the loo at the time, that's bad luck. wonder how to cabin crew faired ?

the manufacturer's advice. LOL. leads to over and under tensioning. LOL. My measurements and calculations showed that the mfr method leads ot tension errors of up to 50 %. likely +/-30%.... anyway..... yes, initial stretch temp , temperature dependent. There's a bit of a compromise between having enough tension with a crankcase temp of say 30 deg C, and having too much at crankcase temp of say , 90deg C. So, still a good idea to take it easy until oil temp up to operating temp (which means crankcase temp , also, pretty much) . If the cold tension is too high, safer to TO with low crankcase temp. If cold tension too low, the opposite... I don't want to pollute the forum, this is about 914 heads ,just wondered what the stud diameters were. I'll look it up. Looks like 8mm. I would be confident the Rotax engineers got their stud sizes correct. the rest is left to tolerances and install .....

Canberra airport, 4k/year for parking and all you can eat aircraft movements is good value for money I think. A hangar will cost ya another 10k. The problem is that without a hangar, I suspect minor regular (pilot) maintenance doesn't get done when it sits in the middle of the grass a few hundred meters from the gate . I consider that if I moved the piper to Cbr, then I'd still need a hangar somewhere to pop into do upkeep maintenance between annuals and 100 hourlys. If the Canberra aeroclub had a hangar space for members to do general upkeep, I'd probably join.

Interesting. I've done the calcs on thru bolts etc for jabs, and I assembled my engine(s) on thru bolt stretch, not torque. However, that's more difficult to do with a stud ! what's the diameter of the studs ? FWIW 100hp Rotax hp /litre/rpm is about the same as the Jab. Jab has 6 head screws (5/16" from memory) . FWIW the jab 7/16" thru bolts dont have much leeway between required preload tension at cold,, the tension at hot (with crankcase expansion) and yield. However, all my numbers were done on min yield specs, so the yield point was likely higher. The Jab head bolts , six of them, there's plenty of tension in hand there.

These are the better ones- again - photoelectric $130. but dual sensor so they know the air density etc also. comes in various gas falvours. https://au.mouser.com/datasheet/2/447/KEM_SE0213_QGC-3317038.pdf

So, something to keep in mind. Most of the "CO" sensors at the low end are actually "air quality monitoring " sensors CO is just one of the detected gases.... you need to spend more money to get a pure gas sensor. but of course there shoul;d be only air in your cabin. cheap one - dual gas https://www.winsen-sensor.com/sensors/mems-gas-sensor/gm702b.html https://www.winsen-sensor.com/product/gm-702b.html for the new solid polymer sensors https://www.sgxsensortech.com/solid-polymer-sensors Here is an affordable one USD15 https://www.sgxsensortech.com/sensor/mics-4514 https://www.sgxsensortech.com/uploads/f_note/0278_Datasheet-MiCS-4514-rev-16.pdf amongst https://www.winsen-sensor.com/co-sensor/

CO2 sorry got mixed up LOL. I'm tired.

given that the atmospheric CO2 concentration is about 400ppm, I'm guessing it is displaying concentration above 400ppm. or a complete BS reading.... still, an increasing number is all that's really required. there should be no CO2 in the cabin. Newer sensors are instant on. but the sensors, even wholesale in large quantity are USD$12-20, which isnt going to sell at BWS for less than $100 for that sort.

but "you guys" don't listen to the cricket

Hi Nev, thanks for the comments . I got tossed in the jabiru 90deg to the ground once, that wasnt fun. Some people would say what do you put yourself through it ? Well, I beleive all good pilots are compelled to confront their demons. It's no fun though. And Young with its rising ground around the AD and hills is full of demons. If my adrelaline hadnt been so high, I would have had another go from the other direction, different hills affect the other end. But I'd need ot be on my game when climbing out through the demons at the other end.

Went flying yesterday, while only 10 kts on the ground from the east , much more once in the air , needed 10 degrees to hold off the drift ..... Got to destination , a known bumpy AD to shoot a few Xwinds ,AWIS said 11 kts and pure Xwind... this AD is in a shallow valley..... and I was so shaken up on final on both passes due to very uncomfortable turbulence I found had no appetite for putting the plane down once over the threshold. Did two. So I went back home. and listened to another airplane go into the same AD and go-around twice and then choose the opposite direction..... I guess they got down. landing in same Xwind component but at Cowra approaches are smooth if when windy and landing in same Xwind like it was a non event....perfect nice 10 deg flap flare and landing. was demonstration grade ! This was a specific flavour of turbulence I have encountered rarely There really are different flavours of turbulence, aren't there.... Some more uncomfortable than others. Clearly, more work required more often. and I was quite surprised to be so shaken up in the circuit that it severely affected my appetite for landing. It's not scary. the airplane is not going to break and the airplane is not goign to get tossed upsidedown. It's just very uncomfortable, creating adrelaline, anxietry etc etc ***Does a human body get better with this when it's of a certain flavour ??????? . anxiety levels were still running after back landing at CWR.

so, you'll need to solder up a few wires. battery will probably need to stay. older ones are heater/catalyst type, they have lifespan the way these systems get LONG lifespan is they usually only sample a few times per hour. I have a CO2 monitor that has a lifespan of 500 hours and provides twice a minute updates. Newer sensors are either micro versions of same with long life sensors, or photometry type that measure absorption spectra. I wonder which type this is.

also, it might not function correctly without th ebattery installed- the battery might need to stay, so we also generate a power off closure on power down.

on the switch is one side of the switch at ground , or battery , or neither ? detemrine with a multimeter what we need to do is put a small circuit in there to generate a contact closure on power up If you push the ON button as the power is applied, and hold for 5 seconds, does it turn on ? Or do you have to plug in, wait x seconds, then hold the power button down ?

how do you usually turn it on ?

Without an ADF radio, how are you going to listen to the cricket ? For nav. There are plenty of ADF nav beacons around. and they are easy to use. but if you have a suite of dual GPS systems + VOR, no practical need

spam

yes, fuel flow *may* edge up due to square law related losses. and and volumetric / airflow behaviour + efficiency has its own curves for each engine system with RPM/ MP

the only practical way the 3300 makes >115hp is with a pitch adjustable prop. then it is fantasic, can run it down at 2400-2600 etc

yeah I think the OP is getting confused with where the VW aerovee engines make their best power Jab 6 cyl : note flat torque curve

WRT sonex - it's unsurprising that a the 120 hp jab goes faster the 100 hp 912ULS rotax . why ? because at any altitude, it has more power. simple...... and power = rpm x torque so forget about talkign about torque. I dont 't know why that is in any contention. ideally, thrust would be presented. that's the final say...

if you change to the composite prop (from the wooden prop) you'll find its worth quite a few horses....

Justin(e) , the Jabiru 2000 hour overhaul... might require a crankshaft , camshaft etc, likely raises the cost significantly. If you are a 19- flyer, then you have your own discretion to assess things like camshaft and crankshaft condition. I understand a 2000 hour full overhaul of the 912 , replacing all the parts that rotax specified must be checked for wear .....is essentially uneconomical . I believe it runs more than 70% of a new engine (in parts) to do all the items. Rotax make it that way intentionally I am sure . They want to sell engines. The Rotax at 2k hours still has plenty of reliable hours left in it , assuming it has a good life with clean oil and little avgas . The Jabiru you really do need to pull it down and do a overhaul. The Lycoming.. well they are known for going more cycles than cats have lives. Again, rebuild cost can vary in experimental categories. As JackC said , flying is not cheap or free to just open your chequebook.

skippy , your comment of : " My current Rotax aircraft seems to be delivering about 15 L/hr, 5200 rpm at 130 knots indicated - how would a Jab compare?" Is not valid for this discussion. We're talking about a specific fuel consumption for a specific shaft horsepower (in cruise for total fuel consumption argument ~ 75% ) . The discussion is aircraft invariant . And no correspondence will be entered into

Yes, agreed, the 2000 hour rotax still has more than likely plenty of hours left in it. you might get a 2000 hour 912ULS for 3k-8k that will do another 1000 hours without cracking a sweat But if it breaks, be prepared to chuck it in the bin (with a set of four sets of rings = $1400 !!! ) The 2000 hour Jab is ready for another top end overhaul. 6k-8k inc new pistons, lifters etc . and Then you could get another 1k hours from it if it was well looked after and had nice clean oil all its life..