IBob

It certainly works very well for me, RFguy: in 230+hrs the only time I have not had near instantaneous and smooth starts, was due to stale fuel after lengthy Covid lockdown. So much so that if I ever start to get less clean starts, I will be looking for the problem. Further to all this: a while back, someone posted a link to a very good video on this carburettor. I did watch it, but cannot now recall where it was. Anyone???

I suppose we are all talking about the same carburettor here: the Bing 32???

Bleuadventures Blueadventures, I don't think that's quite right either: pulling the choke rotates a disk that exposes one of two different sized ports. A full pull is a big port, a partial pull is a smaller port. So a partial pull is still giving some enrichment, I would think (always assuming the main throttle is fully closed).

Skippy, you may well be right. No doubt ambient temperatures have a bearing, and they are normally not low here. All I know is that I have evolved a routine that sees near instantaneous clean starts with a fairly prompt transition to an initial idle of 2200RPM, choke off, during which the engine neither labours nor overspeeds. I say fairly prompt as it is several seconds before the timed ignition goes to fully advanced (at which point the RPM rises). As a side issue, it is worth checking the idle speed (throttle stop) and the idle mixture screw settings, as set out in the line maintenance manual under basic throttle adjustment. These are very quick simple adjustments. My new engine had the throttle stops set correctly, but the idle mixture screw settings were only approximate, and not identical. I have also seen a new 912UL with various idle and running problems, where the problem was incorrect setting of one carb needle. Which is to say that whoever does the Rotax carb settings is not bullet proof.

Skippy, that's odd: when I pull the choke button on the panel, it turns a little disk in the internals, exposing one of two enrichment ports. I'm pretty sure it does nothing whatsoever to the main butterfly.

Skippy, congratulations! As for the choke.......whether it is lockable or springs back, I am ambivalent. Since I only use it at starting the 912 and almost immediately let it go, and since it does not work once you begin to open the throttle, I cannot see a reason to have it lock on. But quite probably others have different needs.

Blueadventures, I believe the throttle bar stop may go some way towards maintaining carb synchronisation. I have the standard setup, with two cables coming from the quadrant bar to the two carbs. Initially, as this bedded in, and as expected, the carb sync required periodic minor adjustments. But since approx the 45hr mark, no further adjustment has been required: I still check it periodically, but it will be almost 200hrs since I last adjusted it. I put that down to careful routing and securing of the cables and the throttle bar stop, which prevents the carb arms being pulled beyond the carb arm stops. And I would count it as one of a very small handful of worthwhile improvements to the Savannah build. The Savannah throttle bar has a centrally placed quadrant, presumably for those wishing to put in a centre knob throttle, but otherwise unused. This comes back and strikes a block of MDP, cut to thickness once I had everything else in, and riveted to the firewall. In the pic you can see the MDP block, it is white and just to the right of the voltage regulator, with the unused quadrant resting againts it.

CScott and Skippy....no disagreement with any of that! And no reason for a newer 912, properly installed and wired, to be hard starting. However, the older ones without the timed spark retard could be nasty: supposedly the spark advanced once the engine reached 650RPM, but the crude circuitry of the ignition module measures that in an odd way, and having seen them 'spit back' on many occasions, I'm not convinced it does it well or accurately. The newer modules have been a huge improvement. At the other end of the process, I get clean shutdowns too. I fitted a stop at my throttle quadrant bar, so that the throttle can be pulled back quite firmly without risk of bending the carb throttle arms, which are light in construction. At shutdown I first go to 3000 and run a mag check (not a very demanding test with warm modules, just a habit I picked up from another flier), then back to about 2000RPM. Then two fingers on two ignition switches, pull back firmly on throttle and switch off ignitions promptly, 1 then 2 as soon as RPM falls. This almost always gives me a clunk-free stop. A lighter prop also helps in this, though mine is a 70" Bolly, so not particularly light.

Hi Supacat, and congrats on your purchase. It's a great machine! FWIW: The S comes with multiple mounting holes for the rudder pedals, suggesting they can be moved forward. Note however that the S has a redesigned fuselage, so it does not necessarily follow that the rudder pedals can be moved in the VG. You would need to look at available space etc. Moving the pedals would require replacing or reworking the nosewheel linkages. You would also need to look at whether the rudder cables would adjust, or need modifying or replacing.

I have a separate choke that springs back: it's the silver knob at the lower left in the pic. The starter switch is just under the throttle, and it works fine for me: throttle closed, fully pull choke, hit the switch, and as soon as she fires my hand goes from switch to throttle. Pause a moment, then feed in some throttle while letting the choke off. My engine does have the timed spark retard, and that makes for much better starting than the earlier arrangement where the spark was advanced as soon as the engine hit a certain RPM. I also have a heavy negative cable from engine back to battery: some years ago i read something from an Australian Rotax guru, who reckoned he had noticed a strong correlation between aircraft with starting/sprag clutch damage problems, and aircraft that relied on the hull for the negative return. A combination of the above has always given me very good starting.

Tried to PM you, CScott, but you don't accept msgs?

Hi NathanS, and welcome to the site. Suggest you contact Mark Kyle, he posts as Kyle Communications on this site. He is the resident expert, and may well be able to help you. You can Personal Message him by going to the little envelope logo on the left (assuming you are on a computer). Select Compose New, type in Kyle as the recipient and it will bring up the Kyles. From there select Kyle Communications and drop him a message.

Brendan, first thanks for posting the link. For future reference, and particularly when posting about accidents and incidents, it is a good idea to post some detail and a date in the thread title. This does three things (that I can think of): 1. It means when someone adds to the thread, and it pops to the top of the "What's New' list, people can see what and when it is about. If what they see is 'Another Accident', every time the thread is added to and it pops up, it looks like yet another new accident......until you read down the thread and realise it is not. Which gets a bit tiresome. 2. It makes it very easy for folk to decide which threads to look at each time they visit the site........they can scan down the What's New, visiting or revisiting the specific items that interest them. So a specific thread title helps with this. Eg I have continuing interest in the recent US Air Show Crash.......and that thread is headed 'US Air Show Crash' with the date, so it is very easy for me to visit or revisit that thread. 3. It helps avoid multiple threads for the same event: again, if the thread title is specific, others are unlikely to start a new thread, so all the posts on that subject will tend to be on just the one thread, and so easily accessed. For me, this site has been and is a wonderful resource........while I was building, and now while I am flying. About the only drawback with the place is that there is such a huge amount being posted over the years, it can be hard to find your way around. The search function is one tool that helps there. And the other thing would be clear labelling of threads. Thanks, and blue skies.

Maybe we should add plunging and plummeting to our Unusual Attitudes???

plugga.....yep, been down that rabbit hole a while back, or one very similar, following an incident. At that time I queried FlightRadar24 as to their altitude data, which was labelled as 'calibrated altitude'. I got no sensible response as to what that was supposed to mean, but I see they have now clarified it some: "Altitude For each flight tracked on Flightradar24 the calibrated altitude reported from the aircraft, which is a pressure-derived value, is displayed. ( Extended Mode S Data received from some aircraft also includes the GPS-derived altitude of the aircraft.)" If further clarification is required, chase down the spec for ADS-B. As for the incident, if you can run down the atmospheric pressure at the time and place, it's easy to make the correction.

plugga I believe the ADSB data has to be corrected for barometric pressure.

Nobody's obliging you to listen to him, Danny. However, it seems to me you are at risk of shooting the messenger here. You may not like the man (and it is evident from the effort you are putting in to dig the dirt that you do not), but whether he is likeable or not is an entirely different question than whether he has something valid to say. This thread is about the recent accident at Dallas, it's not about what Dan Gryder did somewhere else ten tears ago, and there is no connection between the two.

Specifically, we are interest in what the pilot of the P63 was doing. Dan Gryder states that the air boss was directing events by radio, and had asked the P63 to move up, to get ahead of the B17. IF that is correct, then it would explain what appears to be the acceleration, increased turn radius and bank of the P63.

Danny, the AOPA guy gives us a talk on how and why the flying is organised in airshows. It's interesting and useful information as far as it goes but he offers us no insight as to what happened on the day. Juan Browne covers much of the same ground, again it is useful and interesting but with no specific insight. In trying to understand, I am inclined to listen to anyone who can offer genuine insight, regardless of their position and past history. I don't see 'experience in airshows' or 'never got caught up in small town politics' as being necessary qulifications.

So, we have Juan Browne focusing on vertical separation (or lack of it) while this latest analysis at no point mentions that, but focuses entirely on horizontal separation........

Blueadventures, any idea what went wrong that they had to ditch???

That's an excellent description of the ditching/door situation. I would think the UC was damaged during the salvage, Rankamateur: it's inverted forward and if the tail was sticking up, presumably they would have dragged it backwards. Regardless, once the door was no longer held to the fuselage by water pressure, I think you could deform it, if necessary to get it fully open. Or, put another way, the doors are quite light and flimsy when free, only rigid when pressed tight against the fuselage.

Yep, shock is a wild card, even when you know you are suffering from it: Long time ago I rolled a Holden down a very long bank with 3 of us on the front bench seat. When we came to rest there was no glass in the car, every panel was bent, the engine and gearbox were off their mounts and the gas tank was empty, having torn open on a fence we passed through along the way. Our final roll was arrested by a power pole, which stove in the roof just behind us. Sounds dramatic, it was and I'm not making any of it up. The 3 of us were amazingly unhurt, probably because we were packed in snug so didn't rattle around too much. And all in shock: The guy in the middle was gone, unbelted, climbed over the other passenger, out the window, up the bank and was walking in circles on the road. The other passenger slumped and burst into tears and I had to persuade him to get out of the car, which I feared would burn. And once I had him out, I became obsessed with finding my sunglasses, which had been on the front shelf, but had departed along with the rest of the glass somewhere on the bank. I knew it made no sense, but that's what I was doing.

Thanks for the update Blueadventures. And I can well imagine it would be pretty stressful having to wait for the pressure to equalise before being able to open the doors. The ditching advice I received from a hugely experienced pilot pretty much boiled down to 'try to drop it on rather than flipping, as flipping can be disorienting, then move deliberately (don't panic!)' I would think one item to be mindful of would be not to activate the inflatable lifejacket until out of the safety harness and exiting the aircraft: would seem to be common sense (isn't it always, in retrospect?), but we recently had a terrible accident here where an entire small group of whale watchers died under an overturned boat in daylight calm weather: the investigation is still underway, but it seems quite possible they inflated their life vests under the boat (quite probably as they were told to do if 'in the water') and so were trapped under the boat by their own buoyancy. That may not be the case, but as things stand it is difficult to explain otherwise.

That'll be a writeoff, surely: salt water in all those 6061 lap joints. Interesting to hear about opening the doors: I would have guessed that would be the case. And due to the gas strut mounted at the rear edge of the doors, popping them in flight results in the door slamming open, and in at least one case mentioned here, slamming and jamming shut. So, useful to know as we traverse Cooke Strait here in NZ......... I'm assuming they didn't turn over when they hit the water?