Area-51

Sorry just realised you were talking about Royce; thought you meant Remove & Replace... Yes that sounds feasible; some engines also use Wills Rings (gas filled crush rings) instead of gaskets and are located into a purpose groove.

Sorry I could not stop laughing; they sound like cats being swung around under a full moon 😂😂😂

There are no gaskets, care is required not to damage mating surfaces between head and cylinder. There is also a minimum gap specification measured between head and cylinder components post tensioning. Have not observed any copper ring and fail to see the advantage; just one more point of failure gained.

Many modern studs are now designed to be torqued up to yield; hence tightening method of initial Nm tension then series of further 90deg turns to the yield; at which point further tensioning will not provide any further clamping force, just stretch the bolt/stud further. i.e the bolt is designed to hold a specific tension at the yield. Personally i do not think the solution of the 9XX cylinder design is optimum, however it does work sufficiently and is fit for its service application. Regarding bolt/stud elongation there will be a permissible tolerance provided within the Rotax overhauling manual, however the public only has access to the heavy maintenance data which does not cover cylinder stud tolerance data. Most all modern high stress engines with removable barrels will have single use retaining studs where the block barrel and head are retained by a set of through fixings. As an example the early Lotus Elise engines employ approx 400mm through bolt a maximum permissible stretch and also a single use throw away specification. (we had to replace every single cylinder head gasket on every engine due to a factory stuff up on the bolt yield specification; it was too low) Thinking a stronger bolt will provide more tension can then end with component distortion due the component material itself yielding. So its a finely tuned dance of material reduction and fit for service outcome. All Cost/Weight driven

Sorry correction on above; the check on the 127hr 914 provided 010" stretch on all cylinder studs. A bulk strip on a timed out 912UL provided 010" stretch on most cylinder studs, a few had 020", and one 040" stretch.

A set of new cylinder studs for early 914 has just been measured against a set with 127hr service time; almost all removed studs showed 010" stretch; one stud showed 040" stretch. So it is possible to elongate the stud further beyond its designed yield by over or further tightening. As the factory state; the cylinder studs on the early 9XX are single use only items.

Thanks, just wanting to know for maintenance planning... Aware of the block chain micro chip feature; great idea...

Can somebody clarify; the pictures show a "crankcase bolt" missing, and a "cylinder head nut" missing. The two items are mutually exclusive to one another. Loose head nuts have been noticed on the 914 during annuals

What does a blade replacement cost on these units?

Agree... my aircraft first went into the sky in 1998... when i purchased it it was up for the 5 year change next annual; so i did it; and i did all the other hoses on the airframe too! One braided hose was so poor that after removing it and bending it it cracked open. It was not a major hose. It only carried fluid from the fuel tank to the fuel pump on the engine; nothing major, but i changed it...

😂😂😂😂 LSA 3 year mandatory Rotax battery change with genuine Rotax battery required to remain certified!! 😀 👍👍👍👍👍👍💪

Reasons for 5 year rubber replacement timing on Rotax and 12 year component replacement timing on GA craft; things deteriorate with age.

My own AC came with 0.50mm orifice in return line and maintains 3.5psi on the engine pump and 5.0psi on auxiliary with each flowing at 60 and 105 L/hr. The return feeds back into the reserve tank so what ever is left in main always directs back to reserve before overflowing to main; so fuel has plenty opportunity to return to liquid state. Anyhow thread has now drifted some what. Throw the formulas out the window. Get a bucket, disconnect return line, start engine and measure 1 minute of fuel quantity and multiply by 60. Reconnect return line, and check for leaks and hose clamp security before further flight op's.

Math don't lie... 🤷🏼‍♂️ 45L of fuel to zero fuel in 20min, its only going out through the little hole.

There is just no "why" to this; so it will never get off the drafting table. Anybody with a RA PC can go get themselves a GA RPL SEA rating tomorrow and CTA endorsement in a few days of studying and a flight review exam. Add a NAV endorsement and task is done.

regarding the return line orifice. Rotax have there recommendations clearly stated in SB's. The Pipistrel uses the factory recommended size. It takes approximately 20min to pump the 50L right tank dry at a 12L/hr cruise burn. So that works out to around 135L/hr flow through the little hole at 5psi; about 2L/min circulated back to the left wing tank.

All your answers will be found within the relevant MOS documents regarding operating in controlled air spaces.

Comes back to the type equipment installed; certified or not certified; there will be no concessions offered to Ra aircraft wanting to enter Charlie, parallel minimum GA requirements will need to align.

The Pipistrel factory rectification adequately addresses the earlier causal issue of in flight fuel starvation; it provides switched return line routing to the selected source tank along with escape routing for vapour accumulation to the selected source tank breather at the filler cap. An additional observed phenomena of the pre SW121 fuel supply system is asymmetric flow rates from each wing tank while operating in level cruise flight with both fuel taps selected; the right tank would still empty itself prematurely over a longer time frame. (static flow rates while not in flight measure equal). It should be noted there is no compensation porting employed between left and right wing tanks. Employment of engineered dynamic pressure enhancers at the filler cap breather aided flow rate symmetry however was not consistently reliable to mitigate asymmetric flow and premature exhausting of fuel reserve of the right wing tank. The only reliable performance procedure determinable to keep AC balanced was to fly on the left wing tank first until half reserve, then switch to right tank until half reserve then back to left, which will be almost full again after 10-15min, then back to right tank for 10-15min, it will be exhausted, back to left tank, which will be 3/4, for the remainder of flight if required... Alternatively, fly on left tank first till exhausted, then fly on right tank 15-20min till exhausted, then on left tank for remainder of flight. FINAL NOTE, flying with both taps selected can still result in fuel starvation due to suction of air into fuel delivery system when right tank becomes prematurely exhausted. Astute monitoring and management of fuel reserve levels is therefore critical. The post SW121 fuel delivery solution mitigates all these fore mentioned aspects. It should be appreciated the above outcome of the pre SW121 fuel delivery system applies to any similar scenario where the fuel return supply has been routed back to a single tank only without provision of adequate compensation porting between additional selectable source tanks toward redistribution of reserve overflow. Hopefully this knowledge can prevent pipistrel users ending up in the trees after take off or on approach.

Class C will probably be limited to certified LSA factory built ADSB equiped aircraft only. Class D will probably be any Ra aircraft with mode C transponder and radio

The related issue is not likely causal of vapour lock. The cause is likely due to the design of the fuel delivery system between wing tanks and gasolator mounted on the firewall. These inherent flaws have been rectified within the 2016 Virus SW121 variant onwards by employment of an Andair twin coupled fuel/return selector valve and vapour accumulator tanks behind the rear cockpit bulkhead for each wing. All other earlier Sinus and Virus airframes employ a seperate fuel selector valve at each wing tank with the fuel return feeding back to the left wing only. This allows a selected right tank to be pumped dry within 15-20min flying if the left tank is full, causing premature unexpected fuel starvation. This fact is well documented upon other forums along with the official responses offered by the manufacturer, which, at the time was, "fly with the left fuel valve partially open"... It could be presented that the response is questionable, inadequately addresses a critical safety issue, has been recognised by the factory as a real issue due to the upgraded delivery system of the 2016 Virus SW121, and may leave the manufacturer exposed to serious legal action for not issuing an AD to rectify known existing threat to operator safety of pre SW121 produced airframes. Images of fuel delivery systems attached for explanation.

Advertising keeps magazines in print; unsold out of date units have the title cut off the front cover and returned to publishing house; rest goes in the bin.. unsold books go to clearing houses and sold second round discounted retail before going into bin... Trees get grown on plantations once used as farming land, chopped down, sent on ship to paper mill, then another ship off to printing house, then on another ship off to retail, then into bin; everyone gets paid and gretta goes out and gets arrested again.

If the content and copy writing is provided wholly by vendor it will say "paid...."; if copy writing is provided by journalist commissioned by publication then it will not. The publication runs a "story" on the product with the word count proportionally reflecting the advert size and position. If the advert itself is a vendor provided story then "paid..." must be displayed and border added... if you flick through a news paper and see a story with a border around it then its been paid for placement and charged out as advertising, "intentionally politicised propaganda".

Aircraft from Bacchus Marsh...

This is a waste if beer ☹️