Markdun

Yenn, Don and I were once asked by Canberra ATC to identify ourselves as we were flying east from Murrumbateman towards Canberra. He was in his VP2 and I was in a Minimax.....probably around 4500’. They could have only picked us up by their primary radar....and they had no idea of our height. I’m also told that primary radar (Mt Majura) at Canberra also picks up trucks on the Federal Hwy...and that one truck was nearly targeted with a missile when a US president was visiting.

The biggest risk to me from flying where I do are military heavy rotor wing aircraft flying at or below circuit height over my airstrip in what are regular trips for some commodore from Nowra to Canberra and back. They don’t monitor the area frequency (in my case Canberra approach east), nor do they have their own radar turned on. My correspondence with them was to the effect they use ‘see and avoid’ and that’s what they are going to keep doing, and they declined my invitation to land, have a coffee and discuss how we could better maintain safe separation. Of-course, the military are exempt from CASA and ASA rules. I’ve ended up buying a SkyEcho because most of the time they do have their ADSB turned on. It still scares the bejesus out of me after having a blackhawke fly by me (<300m) in and slightly below my altitude on a downwind to land. It also scares me when Canberra approach ‘clear’ inward bound aircraft to Canberra in Class G airspace from Lake Bathurst at 4500’, when controlled airspace at that altitude, doesn’t begin 10nm further in towards Canberra. I always get tge feeling those guys think ATC has the responsibility to avoid conflicting paths from the time they are advised they are cleared and not when they leave Class G....maybe I’m wrong on that.

Yenn, you can cut/grind the back off the TinyTach to expose the battery. Replace with a cr2032, and recover with a small section of old canopy lexan/acrylic and a few screws, or just goop. Like new from the front. Don showed me this. Cutting off the back will also allow the water therein, to drain out....much quicker than Glenn’s suggestion of evaporating the ingested water off, particularly if you take the plane up and do several cycles of spins 🙂 On the rpm reading, my TinyTach also had a two stroke default, ie. on pulse per revolution, not a four-stroke that has 1 pulse per two revolutions. To avoid the resetting to two stroke giving half the rpm, I had the sensor wire wrapped around two HT wires from the same magneto, to produce 1 pulse per revolution. I’m thinking your problem is your maths, not the TinyTach, unless you wrapped the sensor around the HT lead from a coil to a distributor.....do change the battery —- it’s not hard.

Walrus, I was a bit taken aback when I had to ‘apply’ for an MMSI number for a yacht AIS (a slow maritime ADSB type system) and had to photocopy my 40year old, washed in saltwater a few times, radio operators certificate, to prove my qualification....to the very same Cth department that issued me the certificate! The CASA system for an ADSB hexadecimal number is much better. And yes,similar stupid rules say you can’t have expired flares on board, or EPIRBs past the extreme conservative battery life expiry date. Still, I keep at least 4 on my boat and two in my aircraft. If the shit hits the fan, I want the lights to really and truly light up at the AMSA emergency incident room in Canberra, rather than having them think, ‘yet another false alarm’ to check out.

Haa! I once did a review of the Radcoms Act. Found that around 90% of GA aircraft were non-compliant in not having an ‘apparatus licence’ for VHF radiocoms; and small boats were far more compliant with only 60% failing to have an apparatus licence for their vhf radios. It cost the SMA heaps more in not enforcing the rules than revenue from licence fees. My recommendation was to abolish the requirement, including the radio operators’ licence rests for both aircraft and boats....at least for vhf.

I agree Jack. On motor vehicle standards the relevant regulations or statute or code requires the owners or operators of the vehicles to meet the appropriate standards. I would think a purchaser of a caravan that was sold as meeting the appropriate standard but which in fact did not, would have a good basis in contract law to sue for damages etc. I think you will find that the Registrars of Motor Vehicles in each State also has the discretionary power to require the owner/operator to get a certificate or report from a professional engineer that their vehicle meets that standard. Here in the ACT that discretion is used to require registered operators of lpg powered vehicles to get a certificate of compliance for the lpg system every year. Of-course, if a vehicle doesn’t meet the standard and the non-compliance results in damage to others, the owner/operator (as opposed to the driver) could be liable legally. This stems from tort law, which would ask, did the defendant owe a duty of care to the plaintiff, if yes, what was the standard of care that was owed to the plaintiff, was that standard breached, and then what were the damages caused by that breach. But this does NOT apply to Ra-Aus aircraft because, firstly, as an inherently dangerous activity, there is no duty of care owed to participants (due to tort law reform). Secondly, if there was a duty owed (but there is not to other participants....so think about that....a duty would be owed to GA and RPT pilots and passengers, and people on the ground), tge ‘appropriate standard would not be CASA standards (eg.CoA) because they expressly do NOT meet the standard and are exempt (if operated under Ra-Australia)...the standard would be Ra-Aus standards. Which of-course, brings us back full circle to that circular argument that if an aircraft/pilot do not meet the Ra-Australia ‘standard’, they are not exempt from CASA rules. Putting aside tge question about jurisdiction of Ra-Aus to discipline members for non-compliance, a proper court has an obligation to make laws work even when they are stupid. I could give you an example I had when I uncovered that thousands of Crown leases in Canberra were issued contrary to law which expressly forbid the Minister issuing these leases....the deals involved land redevelopment, and failure of both Liberal and Labor governments to charge hundred of millions of dollars for redevelopment rights on public land. Others might call it corrupt, but I can’t comment. The unlawful acts were by Ministers or their delegates, not recipients. The owner of a local airport, among many others, was one of the beneficiaries of this publicly funded largesse. In a strict legal sense,because the leases were issued by the Ministers contrary to the law, they were invalid ‘ab initio’, as opposed to being capable of being invalidated by court hearing. Therefore, all the current leases, bought by unsuspecting families were also invalid. My legal team said there was no question about this, but they said every court in the land would find whatever way the could to prevent our success because of turmoil it would create.

There is a lot of bull here. Public liability.....? I don’t think so. Who is the lawyer? In most States and territories in Australia tort law was modified about a decade ago, to expressly exclude dangerous recreational activities, like RA-Aus flying, from tort law proceedings. Negiligence and ‘duty of care’ just doesn’t apply, if the activity is inherently dangerous (which it is for light aircraft), if there is a notice warning to passengers/occupants etc, or if the student/participant signs a waiver, it just doesn’t apply. The only jurisdiction in Australia that didn’t implement these reforms is the A.C.T.. I doubt the Ra-Aus has any liability over the misdeeds of any LAMES or L2 maintenance people. The truth is that people accept liability themselves....as it should be. It’s only the I’ll-informed, or insurance companies with vested interests, that keep peddling the lie of organisations like the ra-Aus being liable for what their members do. In my view, the key issues are: what is the problem? eg. unairworthy aircraft causing injury or damage to third parties (ie. not the pilot or passenger); and what is the best way to address this problem, eg. Weight, speed, maxim7m number of passengers, system of competence for maintenance people, noting it’s not going to be perfect or foolproof. And the direction of the RA-Aus in just trying to replicate the old, failure laden, overly complex, model favoured by CASA to be buddies with ‘the industry’, doesn’t answer either of these questions. My evidence is that in my experience there are equal proportions of LAMES and L2s who I wouldn’t let touch my aircraft, as there are that are exceptionally skilled, experienced and competent aircraft maintenance personnel. In reality, the aircraft’s owner/operator makes the decision as to who he/she employs to maintain their aircraft (or do it themselves), irrespective of whether they are a LAME or L2...why not recognise this and give guidance on how to make this decision rather than perpetuate the untruth that all LAMES or L2s are competent because they jumped through some regulatory hoops?

Glen, I’ve a couple of new roller lifters at my hanger if you want to experiment with them....guaranteed empty of oil. I could also pull some pushrods....but I haven’t measured them.

For glueing, I use the System Three one to one ratio glue.....the same as I use on my wing spars, ribs, and on structural beams on my 11m yacht. I’m told it’s the same as one of tge approved epoxies for certified aircraft....and good for gluing in high humidity (some epoxies aren’t). When cured it is only a tad harder than E.delegatensis and pretty resilient (ie. not brittle). For coating I just use a local Qld made epoxy that is fairly high modulus, ie. hard and waterproof, but will chip more. Some epoxies are softer (eg. BoteCote) which have characteristics more like lower density wood used in boatbuilding like WRC and are better in that use. I tried these softer types thinking they would be better for leading edge protection, along with Kevlar woven tape....not worth the effort. I now use hard epoxies for coating and prop tape for leading edge protection. If I was making the prop out of low density timber like hoop pine, now I’d probably use the single pot expanding urethane glue. Not as tough as epoxy, but the urethane glue joins are stronger than the wood if the wood is soft. Lots of laminated beams and plywood in my sloop held together with urethane, and it’s over 10 years in the water with a few thousand blue water ocean miles under its hulls....and no glue joins have failed.

Bruce, adding a 175x75x2.4 gal steel C beam to your wing spar will make your wing stronger, but I wouldn’t think that a good thing. The glass covering is mostly about ensuring a thickness of the coating for moisture and abrasion. I think the strength claims are marketing spin mainly. My guess is the glass will also increase the moment of inertia and diminish one of tge benefits of a wood prop. But its swings and roundabouts....I don’t think there’s much in it to worry about.

‘Quercus’ is the genus for the old world oaks down in the northern hemisphere. I’m not sure of the species for ‘pin oak’. The Quercus’ is often used in furniture and was used in boat structure. It has quite obvious ray parenchyma cells which grow out radially...this gives the wood grain an interesting look as well as making it more difficult to split, if I remember correctly from the several subjects Idid at uni last century. It’s also is hard and holds an edge well and resists denting, like our eucalyptus oaks...hence good for furniture. Unfortunately, unlike Huon pine, western red cedar and meranti, it is not dimensionally stable with changes in water content. It will warp with changes in moisture content....so not so good for doors, windows or external. Generally, I think a solid wooden prop would be difficult to make insufficiently strong if you have a reasonable airfoil ie. breaking from flight loads (thrust) or centrifugal forces. The issue are: (a) stiffness. Bending out of shape with rpm and thrust forces). Some shapes are designed so some bending changes the pitch...eg ‘scimitar’ shaped props; (b) robustness, that is, able to take the rough and tumble of a propellor for more than a week or two; and (c) not changing shape much with changes in moisture content. I’m with Spacey in that one can go way overboard on tge different types of wood. Epoxy glues, laminating, and epoxy moisture barrier and hardening coats can overcome a lot of issues. I’m sure an engineer could work out the forces, but empirically we know wood props work. Another, generality though is that the softwoods like Araucaria (hoop pine), Pinus, Douglas Fir tend to be stronger and stiffer than hardwoods (weight for weight)..this is because the wood cell fibres are longer and have tapering ends compared to hardwoods which tend to have shorter wood cells shaped like plain cylinders.....this is the reason toilet paper is made of softwood fibres (harder to tear) and newsprint (sorry, I mean propaganda print) can have a lot of hardwood fibre. I wouldn’t have a problem with using radiata pine or Douglas fir for a prop....as long as I could get clear straight grained planks radially sawn and I used several laminations and a good epoxy barrier coat. But both of them would be a right bastard to shape....neither sand well as the ‘late wood’ (dark growth rings) is very much harder than the lighter coloured ‘early wood’, so any sanding gives one big hills and deep valleys. Definitely spoke shave shaping. I mentioned stability in moisture content. All wood changes size with the seasons due to moisture content changes. This is why one has to frequently re-do prop bolt tensions with a wood prop. Some wood is better than others. Those Taswegian eucalypts sure have a nice look varnished, but they do shrink and grow. Unfortunately the shrinking and growing with moisture content changes is very uneven. Along the grain (longitudinally) there may be a change of less than 1%. From the centre of a tree trunk in a radial line outwards it’s likely to be 3-5%. Still not much. But tangentially, ie. along the growth rings, it can be 10%. So it matters quite a lot how the log is sawn into planks, or more likely, which planks you select. A plank with the growth rings parallel to the longer dimension (when looking at the ends) and with a nice flame pattern on the larger flat surface will warp and cup much more than a plank where the growth rings are perpendicular to the longer dimension. The Douglas fir main wing spars in my Cygnet (6”x1”x15’) are laminated because I could not source radially sawn planks. The other thing about those tassie eucalyptus (and many from the north island) is their density is highly variable. I think it was E.regnans that has a wood density ranging from 250 to 900kg per metre cubed. Spacey, I can’t see any significant benefit of the fibreglass. It just adds another failure possibility, ie de-laminating in flight, as well as weight, particularly if you have a hardwood prop. I know from boat building that most fibreglass sheathing really only ensures a minimum thickness barrier coating for abrasion resistance and moisture ingress, not structural strength.

Spacey, you will find a huge variation in the wood of any of the three eucalyptus species you mention. And I would doubt many people could tell the difference between the wood of one and the other without reference material and a good microscope. I wouldn’t be keen on meranti....too soft despite being a hardwood. I’m sure people could make a functional prop from knotty, tangentially sawn Pinus radiata....probably strong enough, but would it hold its shape, twist and withstand the odd collision with gravel and insects? I’m not sure of the point you are making regarding the broken prop? Did you break it on purpose, and what was that purpose? I would suggest you might want to consider your crankshaft. I had a very minor incident with a half VW powered Minimax with an idle prop strike (landing in long grass)...only a nick and crack on one blade from tip inboard about 10cm. 5 flight hours later total crankshaft breakage at 4500asl with uneventful out landing.

I have mostly used props I’ve made myself, but also commercial ones like Sweetapple and Sensenich. Currently I have 4 props for Jab 2200, 1 for a VW 1835 and another for a half VW conversion. I have the Sensenich 60x46 Jab ‘climb prop’ on my Cygnet and it spins up to 3200 at WOT at 65kts IAS and climb rate of 1000fpm and around 3000rpm cruise of 92kts. A great prop. for this airframe/engine combination. And very smooth. But I think the Sensenich ‘pitch’ is per the chord line and is more like a 42 or 43” pitch as measured on the flat rear prop face. I made a 4 lamination alpine ash (E.delegetenis) prop (60x47) for the Corby after another Sensenich 60x44 gave great climb but crap cruise speed....exceed max rpm. Another great prop, but just not right for the airframe. The alpine ash is much stiffer than whatever Sensenich make their props from and being without fibreglass the ash is lighter. This prop gives me 1500fpm climb at 70 kts or so at an rpm around 3100 and 110 kts cruise at 3200....still hits max rpm before Vne straight and level at WOT. So I’ve whittled a third prop; this time from 3 laminations of plantation hoop pine; 57x48. It’s a tad thicker (weaker and not as stiff as the euc) and has a wider blade area (hence the reduced diameter). I haven’t tried it yet as the current prop on the Corby is just too much fun as it is. On my props I find 3 coats of high modulus epoxy resin then 3 coats of polyurethane varnish (UV barrier) and a reasonably soft prop tape (from Spruce) on the LE works well. It’s not hard to manufacture yourself with a good square, straight edge and profile gauge, hand saws, chisel and various sanders The hardest thing is cutting the holes for the Jabiru spigots accurately. Tthe old VW conversions were easy by comparison because they were centred on a central mandrel. I’ve thought of prop copiers but it seemed like a lot of trouble. I think even really crap shaped props will work (assuming strength, balance tracking is ok).....it’s just the last few percentage points of efficiency that may not be achieved. The comments about the cost of doing it yourself are delusional. The timber is around $150, epoxy glue to laminate say $60 (though you will need to buy at least double that amount), sanding consumables ($30), epoxy saturation resin (another $100), plus syringes, gloves, brushes etc, high quality UV blocking pu varnish ($50), and then there’s your time drawing plans and computing angles and airfoils, sourcing materials, doing the actual work, making a prop balancer. If you can get below $500 per prop excluding your labour...good luck. But then if you make one, you’ll probably end up with making at least 3 before you are content to leave it be. So my guess is, factor on spending about $1500 for making it yourself. There are some negatives of making them yourself though. It is easy to make a poor performing prop by making the blade area too big and the blade too thick because you don’t want it to be too weak. For low HP motors those toothpick props that look ridiculously small seem however, to be the most efficient (some say a single bladed prop is more efficient..so maybe try cutting off one blade, replacing it with a counterbalance?). But how much is too thin? The bigger problem is that if you even consider your current prop is not ‘perfect’, you’ll end up having to make yet another one instead of reducing drag by replacing your gap tape, canopy seals, making strut fairings etc. And if you make a prop for someone else, remember that any and all performance issues will be absolutely due to the prop you made , not due to the engine being 30 years old, well past its TBO, the carb not jetted correctly, the fuel 4 month old, the aircraft exceeding its MTOW by 20%. etc etc. it’ll probably also be the source of noise in the intercom too.

Jasper, no debate from me on that. I just can’t fathom why the Ra-Aus seems to think shmoozing up to industry or providing services and information to the government is in members’ interests. It’s not our role or objective to be well regarded by industry, CASA, or the Government - except to the extent doing so advances members’ interests. How much do we charge CASA or the department for the information about members the Ra-Aus provides them? I don’t give a flying fig what AOPA, the SAAA, Qantas etc think of us....I just want to build, maintain and fly with the minimum of stupid ‘rules’ with no evidentiary basis of need. I’m an adult and I don’t need some patronising father figure to protect me from myself. I note an increasing number of long term members giving up; some flying outside the rules. How stupid is the medical requirement when you hit 70 (I think). The ‘standard is the same, ie. fit to drive a motor vehicle, but if you are old you have the added requirement of proving it. The only justification for such a rule would be evidence that older people are more likely to lie. Where’s the evidence for that? The staged inspections requirement in building is much the same. Where is the evidence of a problem, when it remains that the vast majority of incidents are pilot related? The Airservices class E airspace proposal was, and remains, a proposal without a clear objective or a problem to be addressed (except perhaps being a justification for Airservices expanding its infrastructure spending (ssr and ADSB coverage) to be recovered by increased charges on a diminishing fleet). But ten years or so ago Ra-Aus objected to a proposal that would have seen ADSB out devices like SkyEcho provided free to all of the Ra-Aus fleet (paid for by commercial airlines) that would have made more airspace available to us. Go figure. Rant over....now why has my Hall effect RPM sensor started giving me intermittent higher readings in the Corby, and what’s next on building a canopy mold for a new acrylic molded canopy for the old Cygnet?

Kasper, I agree that your analysis is correct about RAa jurisdiction. Moreover, in law, only a court can impose a penalty. The police, or CASA, similarly cannot impose a penalty. If the legislation allows they can issue a person with an ‘infringement notice’ (a fine) and the person issued with the notice can agree to pay the fine. But it is every person’s legal right to not pay the fine and require the police, or CASA, to take them to court and prove, as per George Pell, beyond reasonable doubt that they committed the offence. Raa-Aus does not have that legal power to take you to court (unless they can start a private prosecution). In fact, I know of a case where a CASA prosecution failed (pre AUF days) because the person in CASA that authorised the prosecution didn’t have the delegated authority to do so. where I think your argument comes apart is Raa-aus, does have a form of contract with members. This is the essence of corporations.....the members (equity holders) essentially have a contract with the other members as set out in the corporation’s constitution or M&A of association. This is what a member actually means (unlike gyms where ‘member’ really means customer). So while the RAa-Aus may go whistle Dixie in regards to imposing fines or periods of imprisonment, it probably can suspend a person’s flying privileges etc, refuse to register an aircraft etc. The ‘rule of law’ is more than just criminal, it also includes contract, torts, and equity (something our PM needs to learn). Of-course, if the person couldn’t care less about their membership and flies contrary to the tech manual etc that’s their business. Arguably, if Ra-Aus is aware, they could dob the person in to CASA. But it seems the precedent set by the reluctance of churches to dob in paedophiles or our current prime minister to dob in rapists or ministers illegally spending our money, it would perhaps be prudent if they kept shtum.

Skippy, a friend with a Rotax is ‘gunna’ put a TOCA on his to decrease warm-up time and reduce the workload involved in the manual TOCA here in Canberra.....gaffa tape on the oil cooler, which is what I use in winter on the Jabs to assist getting oil temps above 65C. I’ve just taken them off for the summer. Bruce, I machined up an alloy adapter fitting that goes between the Jab plenum and the Bing with an ‘airfoil’ shaped brass bar which can be turned with a screw driver and locked in a position with a lock nut. Mine just is vertical, but you could have one horizontal too. I haven’t bothered fitting it as my cruise egt spread is ok....it’s just on climb where it goes all over the place depending on the day and what constellation the moon is in.

The claim that the Bing CV carb is ‘altitude adjusting’ is just marketing BS. It’s a constant velocity carb. It’s not as bad as a plain slide carb but not hugely different in terms of getting richer with increase in altitude. It is much better than a plain slide carb in terms of ‘pick up’ and generally doesn’t need an accelerator pump. Size for size theCV also needs to be a bit bigger than plain sliders and for any given engine the plain sliders are argued by the motor bike racers to deliver a slight increase in power. In my experience the cv carbs are slightly more difficult to tune and much more sensitive to inlet runner lengths....you can get harmonic pulsing of the piston/diaphragm. like koalas and wombats, carburettors are doomed to extinction. Everything is going EFI....more reliable and cheaper. How many people now have glass panels for primary flight instruments? I’ve heard of one in flight EFI failure and that was due to fatigue cracking of a 10cent 10A glass fuse that powered the EFI computer. It should have been an automotive fuse designed for a vibrating environment. EFI is also doomed and will be replaced by E.

I’ve had few silent moments, all with VW derivatives and nearly always due to the idiot mechanic, me. First one was an EFATO from a broken head bolt at 100’, giving one good cylinder in a half vw motor. Zigged and zagged between the eucs and herefords. Cause was secondhand head bolts with a nick in them from the original vw cooling shrouds. Second was a broken rocker bolt in the half vw at 500’ over a dry lake. Third was a broken crankshaft at 4000’. I had previously noticed oil leaking from the prop hub seal ...but did I do anything? Fourth was several broken prop bolts causing a bit of a shaking in an 1835cc vw from wrongly using ht bolts. Landed in a rapeseed field after shutting engine down before it ripped itself off the front completely. Learnt to use malleable bolts and Bellville washers on the prop, but obviously not enough as my fifth engine out was, ‘is that a bit of an increase in vibration?, yes, better go land. Oh, the vibration has gone, and what was that shiny spinning thing that went whizzing off...must be the prop. Gee, the engine is running real smooth now. Now where is that airstrip?’ I’ve never had the ‘too much air in fuel tank’ problem, and I’ve generally considered an engine out as a ‘where have all the thermals gone’ issue that requires an out landing and fly accordingly....ie. only over terrain I feel comfortable landing on. Nev is correct....have a plan for when the engine fails. I would add....practice, practice, practice dead stick landings and speed/energy/glide path control. I do miss the spoiler/air brakes of gliders in my Jab powered Corby! I’ve been much more frightened on a commercial charter in a twin engine Cessna flying to Yuendumu with 8 govt VIPs on board. The plane was critically short of fuel because the pilot the previous day flew several hundred miles off course to the wrong airstrip and he thought that aggressive leaning would get us there. The last 100nm with lots of tapping of fuel gauges and then flashing red lights on the panel the pilot was flying above 4wd tracks between the sand dunes. We definitely took to the whisky at chairman’s lounge at the Alice, and the pilot of the red rat jet we then took to Brisbane kindly agreed to my suggestion he inform the passengers over the speakers that the plane would fly to the correct airstrip, Brisbane, and had more than enough fuel for the trip. My VIPs in first class cheered. Mark

For a Jab 2200 I would have thought 36lph would be about 150% of max fuel flow and ok? I was getting 40lph in my Cygnet, and 33 in a Corby Starlet (both Vw 1835, which drinks a max of around 20lph). Both just had a paper filter in the gascolator. When I upgraded both planes to the Jab2200 I kept the gascolator filter and installed the recommended inline filter....and gravity flow rates diminished to a tad over 30....not good enough, and I blamed the valve springs in the Jab fuel pump rather than the filters. I get over 60lph on both with electric. Still the max flow I’ve seen climbing out at WOT at 3100rpm with the Jab is 24lph except the 30lph ‘indicated’ when the facet pump is turned on....but that is a lie caused by pulsing. I do wonder just how many people test fuel flow rates....it’s not hard to take off the float bowl and collect the fuel in a large measuring cylinder.

Seems a good argument to go back to no fuel pumps, mech or electric, and no pressure gauge, relying only on Newtonian gravitational forces for fuel transport from the tank to the carby, which I did for over 700 hours without a problem. If gravity fails there are much bigger problems to worry about.

This is what I use. 0‑15PSI /4" Pressure Transducer Sensor Output 0.5‑4.5V/0‑5V for Water Gas Oil | eBay Output is linear....0.5V is 0psi, 4.5psi is 15psi. It Does need a regulated 5V supply. I tried a 0 to 10psi model but it failed almost straight away, so hence the 0 to 15psi one, which has given 100hours of no fault operation on a Jabiru engine with mech pump and facet boost pump. My display range is 0 to 7.5psi. (And there we go again with archaic units of measurement,) I know of one problem caused by fuel pressure monitoring on Jabiru and Rotax 4 stroke installations — when the electric facet pump is switched off the fuel pressure drops close to zero for a second or two until the poppet valves in the mech pump on the engine start working. No-one without fuel pressure monitoring has reported this issue. It’s the same logic as Trump has when claiming that increasing testing for Covid increases the incidence of the disease.

Thruster 88 it seems the rest of my reply didn’t make it. But I wasn’t responding to ‘certified and TESTED’, but your previous statement which was ‘old and certified’. I maintain that just because it was done that way in the past, and even if it worked, it’s sometimes worthwhile to look at alternatives. The ‘old certified’ isolators I have come across probably worked reasonably well (‘worked’ as meaning providing reasonable safety), but they weighed a substantial amount. But I think the safety provided by a battery fuse provides similar safety for a big weight saving, and if I’m doing a power off out landing, not having to turn off the battery isolator is one less thing to distract me from getting my landing just so. The sick cow fable. Farmer A who had a sick cow attended the local annual field day. Farmer A explained to another farmer, Farmer B, about the sick cow’s symptoms. Farmer B responded that he had had a sick cow with the same symptoms and that the generally accepted approach was to treat the cow in a certain way. The next year Farmer B saw Farmer A again at the annual field day and asked A how it went with the sick cow. Farmer A responded that he did what Farmer B suggested, but the cow died. Farmer B then remarked that his cow also died when treated that way too.

That’s two fuse holders. The bottom one has a 150A fuse (starter motor), the top one I think has a 50A and goes to the master switch on the panel and a 25A circuit breaker.

You forgot the 10 weeks to a month; ten months to a year.

Old Koreelah, here is a photo.