skippydiesel

Thank Onetrack; very good points . One thing though -" .... is that using the coolant either manufactured by the engine manufacturer, or the brand recommended by them is vital" While I would always prefer to go with the engine manufactures recommendation, this is not always possible or perhaps cost effective. Provided you do the research ie compare manufactures specifications, with your optional suppliers product, you should be okay. All to often the manufacture and or agent,has a ridiculous mark up on their recommended product, when they are the sole supplier eg Continental oil hose supplied exclusively to Rotax.

That's what the latest Euro standards are and what Rotax (a Euro manufacture) have based their recommendations on. You should not be using water with any impurities.

If you are having problems finding Castrol SF concentrate, check out some of the other brands eg Nulon, Valvoline, Shell, Penrite. NOTE: Coolant used should be a low silicate & nitrite free formula Most coolants specified for modern European sourced engines, will meet the Rotax standards but be sure to check.

Sooo Hypothetically; we have an aircraft that flies but to do so requires unacceptable (??) elevator input (up/down). How to fi? Control surfaces are "tweaked" - some improvement but not enough. What to do? stick a bag of lead somewhere? Or might elevator issues not be helped by a small adjustment in engine/prop thrust line? What would you do?

Wow! I would not expect any factory built/supplied aircraft with standard fitments (engine etc) to require ballast - doesn't sound good to me.

For sure! BUT The heavier an aircraft the more energy (power/fuel) is required to keep it aloft - in the event of there being no other option (adjustments to angle of attack, engine prop angle, etc) the best weight will be the smallest (mass) placed as far out on the airframe as is practical taking into account the afromention effect on spin characteristics..

For many years Rotax have recommended collants which were/are designed for European cars, with multiple differing metals in contact with the coolant (mainly low phosphate spec). Rotax cooling systems have several differing metals in contact with the coolant. Aside from increasing boiling point ("antiboil") and lowering freezing point ("antifreeze") other important functions are; the suppression of electrolysis (corrosion) caused an electrolyte (water + salts) and in contact with dissimilar metals (electrode). This can be seen as "pitting" of the coolant galleries (inside cooling system) which can lead to irreparable damage (leaking. etc) anti deposit - older coolant would sometimes build up a layer on the wall of the cooling system which could inhibit cooling efficiency lubrication of "rubber" seals Up until about 4 years ago, these coolants were not readily available in Australia - they are now. The allowable alternative was "Castrol Radicool" (green in colour) it has done a great job and is still a satisfactory alternative to the newer offerings. Most of the main lubricant/coolant suppliers, on the Australian market, will make a suitable coolant designed for late model European vehicles (& Rotax). . Most will be RED coolants Note: The colour of the coolant is no guarantee of compatibility - check the specifications for compatibility. I now use Castrol Radicool SF-O (red) because it is compatible with my various cars & my Rotax - purchased 20L when it was still relativly uncommon. Personally I don't like pre mix coolant - what guarantee do you have of correct 50:50 mixing ratio? I always use "pure water" eg demineralised, RO, distilled and replace at 2 year intervals or according to Rotax recommendation (whichever comes sooner).

Just want to be "pedantic on the use of the word BALLAST🙃: Ballast: Wiki "material that is used to provide stability to a vehicle or structure" Leaving aside structures (inc. railway lines) & vehicles, other than aircraft - ballast is not part of the aircrafts structure, equipment or systems needed for flight. Ballast is a temporary weighting of the aircraft, to satisfy a particular circumstance. Relocating the battery, to meet W&B requirements, is not a ballasting action. Putting a bag of lead shot in the tail is. Personally, I consider the use of ballast to be an action taken after all other correctional possibilities have been exhausted (see preceding argument/statements on the undesirability of ballasting)

Elevators position in cruise; Even easier - On ground (may need an assistant to advise of elevator position) Take a piece of flat board (plywood, strong cardboard, etc) of sufficient length to hold one end against a "known" position on bottom edge of instrument panel (or other convenient fixed structure) and covers expected movement range of stick. Place board end on panel position and along side of stick Neutralise elevator (elevator level with horizontal stabiliser) Mark position of stick Go flying In cruise, mark position of stick on board Land and park Place board on panel and bring stick to cruise position - check elevator relationship with horizontal stab You now know your elevator position in cruise. Simples!

Surly you jest? The AN system operating in both fractions & decimal expression, with overly minute increments, is at best nightmare.

I never throw tools out, even broken worn out ones come in useful occasionally. So I have quite a good collection of imperial spanners, kept well separated from my much preferred/loved metric collection. The imperials have come into their own, with my acquisition of an American designed metal aircraft. I still struggle to know which is the next size up/down and why do some fractional sizes fit, while others with the same fraction embossed on them do not (please don't answer I actually know the reason deep in my subconscious, I just despise the system so much, I would rather pretend not to know 🙃).

I think you will find that Australian flying incorporates a weird mixture of both Imperial & Metric well beyond the few examples you gave - weird indeed. I believe all our Imperial units are of Pommy origin (ie no US Gallons) although Wikipedia tells me the Brits & the Yanks standardised their mile in 1959 (1609.344 m) - no word of consulting with the rest of the World As for your last comment/disclosure - I try hard not to be racist as some of my friends are American😆

Speculation: The only reason we are still muddling along with Imperial (of any scale) is because of the Septic Tanks refusal to adopt the far more logical & intuitive system, Metric. FYI: All international scientific papers are in metric. Metric scales are almost universally used by the scientific community There is no logical reason for having any measurement in Imperial (including aircraft separation) Don't know this for a fact but have heard that at least some of the Yanks bigger companies eg John Deere, have gone metric. The multitude of Imperial scales grew organically, from the human experience of the time, and are no longer fit for purpose, completely obsolete. .

After giving some more thought to this : The two aircraft Risen and Sonera II ; Are both powered by the same Rotax 912ULS engine Have similar empty weights +/- 300kg They only differ in design/construction and presumably the amount of money invested by each developer/builder. The Risen has a "World Record" in the "kindy race" - the Robin Austin Sonerai II VH-SGS has the World Record in the real world. In my opinion, Risens record is very close to Trump truth.

Saw that but confused - Robin Austin / VH SGS claims between 238 & 252 knots. FAI verified as 218 to 237.6 knots - the Risen above is doing 174.5 knots. Just realised - Robins Rotax 912 ULS powered aircraft is in the "Powered Aircraft" class - the Risen also powered by a Rotax 912ULS, is in the "Microlight and Paramotor" class. Got to say sounds like a smidgeon of BS going on - the Risen is, in my humble opinion, neither a "Microlight" or a "Paramotor"

"........ wind assisted." What makes you say that? "Risen claim a record on their site," - yes but only for the "SuperVeloce" which boasts a Rotax 915 - no mention of the SP" .........Risen set a new world speed record at 323 km/h with standard Rotax ULS 100hp." (174.406 knots)

For sure. Thanks for that. Nice to see that Robins record still stands - wonder where the Risen record is?? 😜

One small point - If it transpires you do need more weight adft, than your existing battery (LiPo ?) will supply, what's stopping you using a heavier battery (lead acid?) ?

No! that is until just now. Cant find any mention of SGS or Robin Austin, however I find the FAI Records web page to be very difficult to interrogate.

My point - badly articulated - is that SP is quoting data WITHOUT verification, wherase Robin Austin has his aircrafts performance verified by the FAI. From my perspective , the Risen performance claims are very much in doubt, that is until verified by an independent & recognised authority eg FAI, CAFE. One further point: Aircraft manufacturers/seller have an appalling reputation for exaggerating their aircrafts performance - SP should be doing all it can to debunk or substantiate, where appropriate, false claims.

Agreed . I understand (?) that Rotax 912 ULS is the normal/correct (?) way of describing the carburetted, 100 hp, Rotax engine. IF this be the one quoted it is the same engine as SGS used BUT Robin Austin alluded to a change in fuel management - Rotec?

Will do however past letters(diffrent topics) have achieved little

Does anyone else get annoyed when reading Sport Pilot (SP) reports on featured aircraft? The latest SP features the Risen aircraft and makes some astonishing claims as to its performance - most if not all have no independent third party verification quoted. eg " .........Risen set a new world speed record at 323 km/h with standard Rotax ULS 100hp." (174.406 knots) FYI Australian Robin Austin's Sonerai II has set the World Speed Record - "The Federation Aeronautique Internationale (FAI) is the sole authority for administering all flight World Records. In 2008, SGS competed successfully in the FAI Speed Over a Recognized Course World Record category, completing a 500 Km flight in 68 minutes at an average ground speed of 440 KPH (238 knots : 273MPH). One 200 Km section was covered in 25 minutes at an average ground speed of 467 KPH (252 Knots : 290MPH). The GPS flight logger confirmed ground speeds over 300 MPH at times. SGS also competed successfully in the Aeroplane Efficiency World Record category in 2 weight classes, the best result being a 1200 Km non-stop flight around a closed course using only 43 litres of fuel. That’s less than 7 LPH at 197 KPH (1.85 US GPH at 122 MPH). In all, four World Records were established, exceeding previous Speed and Efficiency benchmarks and remaining today as the best recorded flight performances in each weight category for any aeroplane type."

Sport Pilot - Risen - who said you cant have a slow(ish)stall 38 knots & a fast wing 175 knots (?) VH - SGS Sonerai II /Robin Austin (Australia) beet Risen to this sort of performance

The proper tool can be a bit awkward but a pair of flat blade pliers or even better a modified to suit cheap long nose vice grip, will probably do the job for you. Depending on access/angle - multi grip wrench may also help. Good luck and let us know what your ultimate solution is 🙃.