skippydiesel

"...spare $400k tucked under the mattress.......150kts cruise with a 912ULS and retractable landing gear." It's certainly a Shark🤣 Sonex Legacy, Rotax 912 ULS, CS prop, fixed undercarriage, 150 knots (indicated 5500 ft AMSL) complete aircraft around the $140k AU mark😈

Okay - So I have a Rotax 912uls with Bing carburettors (below) - the amount of fuel being delivered depends on manifold pressure, which can be controlled either with the throttle/butterfly or the propeller pitch. It seems to me that, in theory, the manifold pressure/vacuum, at a given rpm, will be the same whichever governor is in use. My theory does not seem to hold good for load (needing power/fuel to move) must come into the system somewhere.?😈

(Not much activity on the Forum , thought I would put this up for debate) I seek your learned clarification on the above topic; I have always understood that a carburettor engine speed (rpm), is governed/controlled by the amount of air:fuel allowed into the engine. The PRIMARY mechanism that determine the amount of air: fuel is the "butterfly" valve, which the pilot controls using the throttle. The butterfly is opened/closed at will, influences the air pressure/vacuum in the carburettor body, which then opens/closes a needle valve allowing more/less fuel to mix with the air. Then there is the SECONDARY mechanism, the propeller. Depending on blade pitch the propeller will also act as a governor. Fine pitch will allow higher RPM, Coarse pitch will restrict RPM. So - IF I have my 912ULS at Wide Open Throttle (WOT) and I have a Constant Speed Propeller (CS) I know I can use the pitch of the prop to control engine RPM but can I also control fuel consumption. Put another way; With fixed pitch prop, I want to select 5200 RPM for a reasonably economy/ good power, cruise setting. With a CS, engine at WOT, can I select a pitch, that will reduce engine RPM to 5200 FOR THE SAME FUEL FLOW as above (no change in WOT)?😈

Doubters may debate all they want - my information is from the real world; ATEC Zephyr, Rotax 912 ULS, Fiti 2 blade ground adjustable prop, optimised for TO - 100 knots, 5200 rpm, consistent slightly over 12L/hr - flight planned at 13L/hr single pilot, 14L/hr two up - always had more fuel in the tank, at end of flight, than planning indicated. Sonex Legacy, Rotax 912 ULS, Airmaster CS 3 blade prop, 130 knots, 5000 rpm, still working on it however seems to be consistent at around 14L/hr, currently flight planning at 15L/hr. While engine setting RPM, pressure altitude & load will influence the fuel burn, for a given airspeed, I like to have a conservative fuel burn figure that I can use for flight planning. I am not intersted in minimal fuel to get the job done. Back to Moneybox's commuter flight, Cue- Northam. The only concern I have with my fuel calculations, is the Wikipedia information of 110 knots @ 75% power - should this be significantly incorrect, then the fuel planning is out. This is where my advice for real world performance testing comes in. Go fly at various power settings (preferably with full load on board) , work out the fuel burn for the whole flight - decide at what airspeed/power you will commute at and use this fuel burn + fudge factor/speed to flight plan. Not rocket science😈

I am working from Rotax published data AND my own experince of, about 15 years, flying behind a Rotax 912ULS - you want a working fuel consumption figure + a conservative fudge factor for planning purposes - you now know how to arrive at it😈

"I wish I could confirm everything you say skippy but it's a bit difficult to calculate while the plane is sitting in my backyard " I hope you will take the time to test fly the Sportstar - a significant part of this will be calculating fuel burn at diffrent power settings. Fill tanks to brim, Load passenger seat (if no passenger use ballast) Go fly for, say,an hour. I would start with a high power setting (worst case/highest fuel burn) 5500 RPM - Note altitude, OAT, Indicated airspeed & Ground speed- Land Note time (Hobbs) Measure fuel into tank to same level. Calculate fuel burn/hr at that setting. Same process at lower power settings. I would not go below 4800 RPM. The result will be average fuel consumed for the whole flight, including run up, taxi, climb, cruise descent. Try for consistency. Rotax publish estimated fuel consumptions at various settings; Cruise (98 RON) 4800 RPM, 65% /29.5Hg/13L/h 5000 RPM, 75% / 29.8Hg/14L/h 5200 RPM 30.0Hg/15L/h 5500 RPM 30.1Hg/19L/h I think these are correct (not sure)

Wikipedia: 110 knots @ 75% power Rotax 912ULS, 75% power, would be 5000 rpm for a 14L/hr fuel burn. This is about what I get & conservatively plan at 15L/hr. So assuming Moneybox Sportstar engine has been well tuned/running as expected, he should be able to achieve; 65 L / 15 L/hr = 4.3hrs duration to near empty tanks. Dont want to risk that, so allow 10L @ reduced power 14 L/hr power for 42 minutes reserve. 55L / 15L/hr = 3.66 hrs duration x 110 knots, for a still air distance of 402 Nm (744.5 km) So Northam at 262 Nm /110 knots, 2.6 hrs (still air) fuel burn @ 15L/hr 38.5L consumed, leaving 26.5L (1.7hrs) should be no problem at all. ( Ground speed (not air) is the deciding factor - its very easy to have a 25 knot head wind that will reduce your range to a white knuckle approach to Northam) He will still need some way of transporting ULP from servo to Northam airfield, for a safe return to Cue, but I think he has that covered.😈

Hi BurnieM - Where does the 18L/hr @ 100 knots come from?😈

Yes to the strategy. My plan, such as it is - in order of preference; Research each fuel stop carefully, try and find the name/contact details of the local Flying Club/business, to beg a ride/ borrow a vehicle, for the, hopefully, short trip to the nearest suitable ULP provider ( this has worked before). Call a taxi - some drivers may not want to carry fuel. Use AvGas - made a "shandy" once - high cost, nil performance gain, got me airborne. Carry some additional fuel, for on ground top up, to get me to a more helpful airfield😈

"Looks like you can carry fuel in portable tanks/cans as long as it is non-commercial and no passengers. Not suggesting this is a good idea. Anybody care to comment." The carriage of extra fuel has a long history. Even today aircraft are "ferried" (ie flown) long distances with the aid of additional temporary fuel tanks (usually bladders). I would be surprised if there is any legal restriction on the carriage of additional fuel. Obviously there is a increased risk in doing so. Common sense would suggest that the fuel be carried in robust containers, well secured against turbulence/rough landing, etc. Fuel extending bladders can be purchased from the likes of Turtle Pack https://www.turtlepac.com/products/air-drop-fuel-bladder/ most of the Turtle Pack offering, is designed to allow in-light fuel transfer - you don't have to use this feature. If you do it will have to be plumbed into your existing fuel reticulation system. Personally I don't like rigid fuel containers - space is at a premium in my little aircraft, they take up as much room empty, as full. I use 20L x 2 collapsible bladders - mainly to fetch ULP from the nearest service station. My flight plan across AU has highlighted that I may need to be able to fetch 60L at a time from the servo, so will need to purchase a third bladder or make an additional trip. 😈

Empty weight (Zero Fuel) is dependent on what systems have been added/order with the aircraft. Most manufactures publish a low empty weight, so that they can claim a high payload (passengers, luggage, fuel). Then they tell you you can fit the aircraft out with a range of non essential (for legal flight) extras, that will then increase the empty weight, detracting from the payload. Your aircraft is factory built, came with /without factory fitted extras - you are not supposed to modify it, without factory authorisation. IF your aircraft is registered as a 550 Max TO, thats the legal permissible weight. IF later aircraft went to 600kg Max TO, the factory may authorise an increase (on application) for your aircarft - this will not only depend on their good will, also any changes that may have been made to later aircraft, to allow the weight increase eg later aircraft may have had a wing tank option, structural upgrade, stronger undercarriage, etc Fuel load can be varied, to allow for heavier Pax/luggage WARNING this will reduce your still air range, meaning additional fuel stops may have to be planed.😈

Ah!

While its important you understand the principal, the main objective is passing your exam - don't start introducing variables, like altering the empty W&B. KISS principal! As far as 4.5.2.2 goes - likly a poor Czech to English interpretation OR a larger fuel tank was/is an optional order. As for installing adjustable position load rails, no need, KISS again - Know your Max weight for the location, weigh the stuff, heavy items as far forward in the baggage area as you can (if no passenger, on that seat), lighter stuff aft. When you have your Certificate, you can then ponder W&B loading 😈

My apologies in advance if this solution has already been suggested; OzRunways has a nifty weight and balance calculator, that can be configured/personalised for your aircraft. Once configured, you only have to put in the variables (fuel quantity/weights in location) and it tells you if your aircraft is within/out - simples!😈

Hi Marty, Is this a Rotax 912 installation? If so, Why do you need an overflow tube? I am on my second 912 powered aircraft - neither have an overflow tube, from the the expansion tank. I have never experienced coolant overflowing from the expansion tank. Assuming correct installation & filling of the coolant system, the cold level for the expansion tank should be 1/4 to 1/2. This will leave more than enough room for the hot coolant to be contained within the expansion tank.😈

This my panel. Switch/Breaker information all in laser engraved, adhesive plaques. Not too shabby?😈

As , I think, has been mentioned - having an engraved, stick on plaque can be very professional looking AND if any changes to the panel layout are made easily adjusted. Engraving the panel itself, pretty much sets it"in stone" future changes will either look messy, wrong or require replacing the whole panel at considerable inconvenience and cost😈

Expanded airspace access for sports and rec pilots Sports and recreational pilots will get expanded access to controlled airspace following industry consultation and detailed engagement with approved self-administering aviation organisations (ASAOs). A summary of consultation was published in December and we're now working through the feedback to ensure we can implement this General Aviation Workplan initiative safely for all airspace users.

IF (??) the manufacturer is supplying a structure that has been "certified" for wind gusts in your area, they would be taking one hell of a risk if the structure was not up to par , of not only claims against the structures collapse but also for anything contained within and if iparts blow away and damage done elsewhere - whole thing could become very costly.😈

I have never heard of CASA becoming involved/setting standard for hangers - I very much doubt thewordy of the one and only Cue hanger people. Having a structure that will not blow away and do damage, is a reasonable position. Their structure/hanger doesn't sound so crash hot. There are standards for public airfields / ALA's - dimensions of runways, distances from obstructions, slope, surface. et etc etc Is Cue an air port ? (as in irregular or regular passenger service RPT)If so there may be more stringent requirements. My research into a prefabricated shelter for my aircraft, would suggest that the suppliers must meet/exceed the wind standards for the area that the kit is being erected in - sounds like a reasonable requirement to me. If local Council maintain the strip, likly they will set the standard for any structures - check it out!😈

CASA? - You sure? Who owns the airfield?😈

You can purchase a 3 car garage or farm shed kit for about $8,000. There are discounts' from time to time down to close on 1/2 that figure. If its a 3 car garage or shed with a suport in the wrong place, need to factor in some additional truss stiffening, to allow for a span wide enough for the aircarft. I guess transport is a big factor for you.😈

If , ""they are not going to tell you what they do or how they do it." how on earth do YOU know???? Forgive me Turbs , this is your paranoid "Achilles heel" at least I am working from experince, & logical argument. I think I will leave the debate, for the moment, even I get tired of repetition and circular argument😈

Something that seems to elude you Turbs - All bureaucracies have a vested interest in inflating their own importance. They are effectively in competition with every other department for funding. Our security services are no diffrent in this regard. For this reason alone their commentary, on something like ASIC is suspect (thats if they even care to comment on such an insignificant failed policy.) Unlike you ( all knowing person), I can only speculate from a recreational pilots view and an retired employee, of almost 30 years service in a bureaucracy; Safety & Security are wonderful vote/funding vehicles, for both politicians and bureaucracies. Unfortunatly they have a significant downside - very hard to pull back/rescind, once enacted, no matter how hysterical, inaccurate, wrong, the initial reason (possibly the best large scale example, in recent history, would be the Iraq War/Weapons of Mass Destruction - killed many thousands, destabilised the Middle East and incentivised a whole new generation of radicals against the West - top job! ). When it comes to ASIC, AS APPLIED TO SMALL REGIONAL RPT AIRFIELDS, the evidence is well and truly there, for any pilot/ intersted person to see - its complete failure, BUT it continues for the above reasons - its in the too hard basket.😈

"I believe that the primary justification for the ASIC was to stop unauthorised persons from being airside in any capacity at a security controlled field." Agreed & seemed reasonable at the time (2011/12) Ill-conceived , from the start, the main criteria, RPT airports, were the only ones considered. These could have as little as one or two flights a day (possibly less). While non RPT airfields like Bankstown/Sydney may have hundreds/day were not included - make any sense??? "All because nobody, not Home Affairs, not airfield owners (mainly councils) and certainly not CASA wants to fund it." No rational person or authority wants to fund an ineffectual program - The "crime" here is not the initial good intent of the legislation but that it continues long after everyone has realised its without merit. "But lets hit users for $300 every 2 years for something we know is ineffective." Seems rational to me - If you don't want to fund it or get rid of it, get someone else to pay, at least for the basic running cost of the life support system😈