RFguy

flat top pistons were still used up to at least3300#2575. (mid gen 3) the springs in jabs are weak. I went right through that investigation, and it is elsewhere on the site- jab valve springs are about 1/3 the tension that those lifters are usually used with. Double springs are approx same overall tension as singles. New head. simple fix. you might replace the rocker bushes while you are at it. (small arbor press required) - watch out for slithers of the material being extruded during the extraction and insertion)..

time for a new head. Jabiru South Africa. AUD1250 I think

Looks like quite alot of recession there- or is that a high crust ? Alot of recession would indicate long term overheating. remember, once they get soft, essentially over tempered, its all over even if you keep the temperatures down....

I think the "there is no point unless it makes a 5 knot difference" statement is not the right way to look at it. Many 5 knot gains come from numerous 1 knot gains all put together.

yes, grounds carry return currents. because the ground wire of your speaker carries significant current, if it shared a ground wire with the microphone, there might be enough voltage drop in the (common) ground wire , and inject voltage into the microphone circuit, and you could get feedback. happy to do a diagram... so, where possible, bring the mic grounds and the speaker grounds back separately to these pins.

Hi Neil- good info - yeah- SKyecho should see a 200W TSO Mode S about 30nm away, if everything is goign for you ***However for terminals right above or right below - there is (usually) significantly less antenna sensitivity for a body mounted whip antenna above and below - compared to our on the horizon. probably reduces the immediate up and down range by 10x . which is rarely an issue.... once outside a 60 deg cone, you're probably less than a factor of 2 down on max range.

geez you lot.... doom... gloom battery wont catch fire if installed and operated correctly.

I would not expect a TSO receiver to pull in any better than a the Skyecho receiver - assuming they had the same antenna. That's unless the skyecho implementation was suboptimal, and I would have no reason to think that it is. The skyecho ( internal ) antenna is compromised to some degree because of housing, PCB location, internal airplane bits etc The TSO uses an external antenna but might be connected on a piece of lossy cable (but if the correct teflon orangey stuff is used, probably not) . On transmit though, the TSO device will usualyl be 200W, 10dB more than the skyecho into the known antenna, and likely to have at least 3x the range of the 20W unit. (for same antenna) Range from TX skyecho to an air services ADSB base station should be at least 20nm - the ADSB base station uses gain antennas (amongst other things) . all calcs assume optical line of site. -g.

on average, expect about 10nm line of site on transmit from a Skyecho to another Skyecho... Yep - a man's Mode S runs 200W pulse...and a good antenna.

Norm for canberra in winter. fog rolls in 15 min after sunrise and hangs around till 2pm.

Battery fire risk is extremely low if properly designed, derated, sourced and qualified. especially you are you willing to sacrifice 20% in capacity to have a battery that will never catch fire from a maximal capacitor/weight type. (LIFEPO4 versus Lithium Polymer). But Lithium batteries with new elecrodes, etc are much much better They get a bad rap from the bad old days, and all the sh1tbox batteries used in scooters etc which are often the factory seconds......

batteries are to electric as fuel is to ICE motor controller for electric is a carb/thottle body is to an ICE a brushless motor is to electric as the pistons and cylinders are to an ICE not sure where fuel vapourization, fuel contamination, fouled plugs, worn rings, burned valves, worn bearings and lobes, leaking gaskets, broken thru bolts, CO2 poisoning , selecting wrong tank, mixture controls, detonation, bad leads, faulty magnetos , intermittant starter solenoids not sure where they all fit in to electric, in analogy.

And quality of instructors, like all industries varies enormously. I've flown with about 4 instructors : There is teaching the basics, which any 25 yo flight instructor can do. And then there is teaching airmanship, something I have only felt well communicated by the older folk. glen

Most likely, the motor controller, a highly complex , specialized bit of electronics may have failed. Batteries DO NOT disconnect themselves from the load if they overheat- Well maybe some consumer POS you buy . There is temperature and balance awareness for the charging system, that's all. Best option is a 2nd motor controller, or a very well derated single controller that never gets hot. Or a 2nd motor and controller on single shaft.

Dont quite agree, but anyway that's fine. by the way, PULP has a higher vapour pressure. ... not lower, than 100LL, but I think that's what you meant. I have thought a bit more about my (wrong) use of the phrase "sort of surprises me because I would have thought that only 7:1 Lycos would tolerate the ULP quality issues. " ( with reference to suitability for 8.5:1 compression also for the MOGAS STC) But the STC relates to fuel of a particular standard. Then in practical terms, this means probably buying PULP in a drum where there are no quality issues compared to the variability of running automotive bowser ULP. IE if the PULP you are buying meets the STC standard, then its fine. Buy automotive ULP, and your mileage (and altitude! ) may vary. If 95RON PULP (just ) gets you over the line (min = 94 RON equiv) , then if using automotive bowser PULP, you'd be wise to give yourself some headroom I suspect by using only 98 PULP. Putting aside potential of adulteration of the fuel....

I'm in the process of buying an Archer. The 8.5:1 Lyco has a MOGAS STC, which sort of surprises me because I would have thought that only 7:1 Lycos would tolerate the ULP quality issues. So they must be tough......and 8.5:1 isnt all that high. The engine is originally factory specified for 91/96 MOGAS (~ 91AKI) which is something like (AUstralia) 94RON from memory (will check) but the heads do get hot. enemy #2 of course is the higher vapour pressure. but clearly, with STC issued, not seen as too much of a Vapor lock problem , as least evidently... low wing, aux fuel pumps . maybe in warmer weather if you do not use the fuel pumps on takeoff there is a low pressure in the lines == vapour bubble issue which could cause trouble at the wrong moment just after takeoff... Potential for trouble also at high DA.....It might be something I only use in winter..... . See my earlier posts of symptoms of vapour in the fuel lines- cycling fuel pressure over 20-200 seconds I'll dig up the STC and take a read to what was done. and if there is any specific placarding. And remember MOGAS does NOT mean 'automotive bowser dispensed'.....

The other thing is, in the ACT, there is a new rule that requires medical practitioners to (compulsory) advise the ACT motor vehicle regulator (vehicle license) , or CASA (air) if their patient has anything out of tolerance. IE the patient has no say in it. This has caused an exodus of ACT heavy vehicle licensed drivers apparently, and medical doctors dont like it either.

Starter pulls about 150A at 10V for a 3300 with good compressions. at oil and engine cold @ 18 degC.

yeah but you didnt give those in the same post, you had different posts with different things in them ! still, overall sounds like good performance.

it's a good video.... Looks bad for Continental, good for Lycoming. and less than ideal for continental company behaviour.

And , a fully charged , unloaded (but not on the charger) 12V lead acid AGM battery at 50 deg C would read about 12.15V where as at 25 deg C would read 12.6V Any attempt to charge it at high temperature, with a non temperature compensated charger would very much overcharge it

Well... you mentioned "23.3 in". was that manifold pressure , or just the pressure altitude ?

ahh so that's wide open throttle then (IE manifold pressure is approx same as (static) air pressure) ? or is that Manifold pressure gauge ? .

Jabs are air flow forward facing and jabs dont have any problems with their fuel delivery.

What type of battery is it and what is the terminal voltage ?? If it has not been below 10.5V for any sustained period (weeks) , its probably fine. a footnote- those deciding on battery location, consider heavy FRP non conductive cover over the terminals- consider what might happen in an accident and have say, an aluminium panel or member squash onto the battery terminals. Now you have a fire. I have seen MANY experimental aircraft have this flaw (in my opinion) , and some factory 24- aircraft.