FlyBoy1960

warm it up (the thermostat) with a hairdryer/heat gun until it's nice and toasty and then add your oil ??

no

I don't think you are correct with the Woodcomp props, they are manufactured in the Czech Republic and I doubt they were ever fitted to the original gazelle aircraft in the 1980's. Woodcomp are still in business, so there should be no issues in getting them but I am 100% sure they were not fitted as standard equipment to the gazelle aircraft. WOODCOMP came into existence at the end of the year 2000 as a result of the merger of the two largest producers of aircraft propellers in Czech Republic having the rich and long-term tradition.

I know this, but it came from their FAQ section

(turbulence) It has to be if what you are balancing is vibrating. Changing pitch alters: Blade aerodynamic center of pressure Torsional load on crankshaft Gyroscopic forces Engine firing pulse coupling Blade flex characteristics So even though the mass imbalance doesn’t change, the way forces transmit into the airframe does. and for best results you must do the balance at cruise rpm AND cruise pitch, most probably while flying ? If you balance in fine pitch but fly mostly in coarse pitch: The aircraft will still vibrate in normal flight. From the Dynavibe manual FAQ's

you need to think about a propeller flying through the air, much like a wing on an aircraft. If you increase the angle of attack on the blades by going to course pitch you are effectively doing what you would do by pulling the stick back and getting stall buffeting in an aircraft. That is probably whether vibration is coming from. It doesn't help that you are sitting on the ground just beating the air.

more cavitation ? loosing the laminar flow because tha AOI is to high and your losing air in the boundary layer ?

Single blade with counter ballance.

any guesses on type ? Looks like a Cessna (i mean really, not a journalist's Cessna)

Facthunter, the problem is in a cooling situation the pipes contain positive pressure. In the carburettor location they are in negative pressure, i.e. vacuum, so I don't get what you are saying ?

Show me some that have run for 2,000 hours please. Everything works well in the first 200 hours, even a Jabiru

Thanks - I will go and do it now.

Is there a way to BLOCK a user/person when their contributions and comments are not worthwile ?

It's ROLL out, not ROLE out. It's FLARE, not FLAIR. 💯 (Flyboy - The grammar Nazi)

Measured with a surveyors wheel, meant to be accurate. Seen the video and hard to tell height, but very low and didnt climb.

The idea was the GSCC (council) would cut the trees over a 2-6 month period for training, the club would remove the stumps. Just a shame it didnt happen when the committee changed a few years back, i will bring it up again in the next meeting.

We extended all the way to the river several years ago and gained 100 meters extra, check the Google Maps and you will see what was gained. Just a little bit more for safety. They were also going to clear the tress that they crashed into several years ago but the committee changed and it was forgotten. If they did clear then we might have had a different outcome. The Gold Coast council agreed to use the area for chainsaw instruction for their parks people and we would have got the trees removed for free, shame it didnt happen.

800 now, there were extensions

The old GPT actually has an opinion. Overview: SmartCarb-Style Fuel Systems What it actually is: The SmartCarb is a modern, single-circuit mechanical fuel system that uses a patented metering rod + venturi design instead of traditional jets, claiming better atomization, automatic air-density compensation, and simpler tuning compared to conventional carburetors. Typical claimed benefits (manufacturer): ~25–30% better fuel economy vs stock carbs (same conditions and riding style) — SmartCarb quotes this on their FAQ. ~8–10% more power due to improved mixture delivery. Reduced need for altitude/temperature jetting changes. Better atomization and smoother throttle response. How it works: • Traditional carburetors use multiple jets and circuits to deliver fuel/air ratios at idle through WOT; SmartCarb uses a metering rod in a precisely shaped venturi with internal float bowl venting to proportion fuel directly to actual airflow. Pros vs Conventional Rotax/Bing Carb 🔧 Pros of SmartCarb-Type System 1) Potential Fuel Savings & Efficiency Independent tests (on motorcycle engines) saw near-30% better mileage vs a stock carb (e.g., 31.5 mi vs 24.7 mi with same fuel), indicating real world economy improvements under some conditions. 2) Ease of Tuning • Only a few adjustable parameters (metering rod/Air-Fuel mix) vs jets, needles, and multiple circuits. • The system compensates automatically for altitude & air density changes better than conventional carbs — no jetting changes needed for moderate elevation shifts. 3) Better Atomization & Throttle Feel (Anecdotal) Owners frequently report sharper throttle response, smoother mid-range, and fewer plug-fouling issues — especially when stock carbs are poorly jetted. 4) Reduced External Complexity • No external vent lines. • Sealed float bowl reduces fuel spillage and evaporative loss. Cons / Practical Limitations ❗ Not Designed for Aircraft Rotax Engines • SmartCarb products are targeted at motorcycle & powersports two-strokes — sizes listed for 65–500 cc dirt bikes, quads, etc. • They are not certified or widely used on aviation engines like Rotax 447/503/535 etc.; aircraft carburetion requirements differ significantly and involve strict safety/FAA standards, including fail-to-run criteria that SmartCarb designs don’t meet. For example, Rotax-owner discussions note that SmartCarb would fail aircraft safety requirements because the linkage design does not guarantee fail-to-run behaviour required for aviation carburetors. 🔧 Potential Performance & Tuning Issues Some users on dirtbike forums report mixed experiences — from great performance to difficult idling or reliability issues, depending on setup and rider expectations. Like any carburetor, incorrect tune, float issues, or installation errors can negate benefits. Two-Stroke Premix & Fuel/Oil Concerns This is a key point many folks miss when talking about leaner operation: ❗ Two-Stroke Premix Oil Ratio Moves With Fuel In a premix engine (e.g., a Rotax 447/503/535), the oil is diluted in the fuel. If you lean the mixture (less fuel per air) to save fuel, you also reduce the oil delivered to the engine proportionally — potentially affecting lubrication. The old pilot wisdom holds that two-strokes are always run slightly rich to maintain cooling and lubrication — the fuel itself carries heat and oil. Going lean to save fuel can raise combustion temps and reduce oil film, which might increase wear or risk seizure, especially in aircraft applications where reliability is paramount. Oil Injection vs Premix: • With oil-injection systems, oil delivery can be decoupled from fuel flow. • On premix engines, any change in fuel flow directly changes the oil ratio. This is often overlooked in fuel-saving discussions outside aviation — on bikes, it’s less critical because oil injection often handles lubrication ratios, but on premix aircraft setups it’s a safety nuance. Performance Differences (Conventional vs SmartCarb) On Conventional Carbs (Bing on Rotax) ✔ Proven reliability in certified engines (when properly synced/maintained). ✔ Stable and predictable fuel delivery in certified operating ranges. ✔ Well-understood failure modes and maintenance procedures. On SmartCarb-Style Systems ✔ Can yield noticeably improved fuel economy and consistent mixture across environments. ✔ May improve throttle response and reduce altitude tuning hassles on small two-strokes. ❌ Not inherently safer or aviation-certified; not predictable under all failure modes required for flight carburetors. ❌ Automotive/moto carbs simply aren’t designed to meet aircraft safety certification.

I just love it ! There are only about 10 people left on this forum, and now you are all fighting amongst yourselves! This resource is slowly self-destructing.

the pneumatic ones made by Carbtune are really good, they used brass rods and didn't bounce around like gauges. I have also used a digital balancer from Aircraft Spruce called the carb mate https://www.aircraftspruce.com.au/catalog/eppages/ts111kitcarbmate.php it seemed to work really well also

whatever happened to the lever system that was being developed by Kyle Communications ? you would set up this system once and it would seem to me to be able to stay in balance for just about forever, then you don't have any issues with cables because there is only one cable going from his system to the pilot hands. Using pushrods or hard connections for the throttle seems a no-brainer to me because there is nothing to stretch or go out of adjustment

On a Rotax 912 (twin Bing carbs), that “balance pipe” is basically a plenum-to-plenum equaliser between the two intake sides. It primarily: Equalises manifold pressure between the two sides (helps share load between carb/intake pairs) Damps pulsations (intake pulses are strong on a 4-stroke, especially at low RPM) Can slightly influence idle/off-idle smoothness and how stable the carbs feel during synchronisation What changes if you go from ~8 mm ID to 20 mm ID? Area matters a lot. 8 mm ID area ≈ π·4² ≈ 50 mm² 20 mm ID area ≈ π·10² ≈ 314 mm² So you’d be increasing cross-section by about 6.3×. That means the balance connection stops being a “small equaliser” and starts behaving much more like a common manifold link between the two sides. Likely effects you’d notice (if any) 1) Idle and low-RPM smoothness could change (sometimes better, sometimes worse). A larger tube usually reduces pressure difference between sides more quickly and can dampen pulses more. That can make idle feel smoother if you currently have unevenness between sides. But… if you go too large, you can also create a situation where: one side’s intake pulses strongly influence the other side, mixture distribution and response around idle/off-idle can become less “crisp” or occasionally hunt/surge depending on how the rest of the intake is configured. 2) Carb synchronisation behaviour can change. With a big balance pipe, the two sides are already heavily “averaged together”, so: it may become harder to detect a small imbalance using manifold pressure/CarbMate-type methods (because the balance pipe masks differences), you might end up with an engine that seems balanced by reading, but still has subtle cylinder-to-cylinder inequality. 3) Midrange and high-RPM power: usually little to no improvement. At higher RPM and larger throttle openings, the balance pipe generally has minimal benefit because both sides are already flowing heavily and the pressure differences are smaller relative to overall airflow. A larger balance pipe typically won’t give you more power. 4) Risk of unintended side effects goes up. Going to 20 mm ID is a big jump. Depending on your exact intake layout, you could introduce: odd transients (tip-in / tip-out throttle response changes), cross-feeding effects if one carb is slightly richer/leaner than the other, potentially more noticeable issues if a carb/diaphragm/jetting problem exists (the big pipe can “share” the problem). The practical/engineering takeaway A balance pipe is usually sized to equalise slowly enough to damp differences but not so large that the two sides become one big coupled system. Jumping from 8 mm to 20 mm is not a small tuning tweak; it’s a redesign of the coupling strength. What I’d recommend instead of going straight to 20 mm If your goal is smoother idle / better balance, you’ll usually get more reliable results by: doing a proper carb sync (idle stop + cable sync at ~3500–4000 rpm), checking diaphragms, intake sockets, clamps, balance tube condition, and any vacuum ports/caps for leaks, confirming float levels and correct Rotax compliance items (many “roughness” complaints are float/diaphragm/leak/sync related rather than balance tube size). If you really want to experiment, a safer approach is incremental (e.g., 10–12 mm ID) and verify with: EGT/CHT consistency (if you have it), idle stability, plug colour / fuel flow consistency, and repeatable run-up checks. One key caution Because this is an aircraft engine, changing intake hardware can have certification/maintenance and safety implications depending on your aircraft category (RA-Aus, experimental, certified installation, etc.). Even if it “runs”, it may not be a compliant modification.

Go out in a gyro, come home in a helicopter. Sounds like a normal day for some of these guys.😇

it's not about what everyone else loves it is what you will be happiest owning and flying. I thought I would use AI to get some more information. There were only 66 Skyfox CA25N Gazelles ever made, 61 were sold in Australia and the other 5 overseas. This does NOT include any that were made after 1996 which was apparently when the factory was closed and reopened under new ownership. The new owners apparently built 3 with 1 being sold and the other 2 being used for parts because they could get more money for them than selling them new. most of this information came from Wikipedia and the Queensland air Museum according to Chat GPT. Interestingly they were about 3 times more X-Air aircraft sold in Australia, probably because they were cheaper and could be kit built ?