Bluey

Make sure the gap between the mast and the hang bracket is completely closed. Ie, you should not be able to see any hint of hangbolt between the mast and the bracket. Tighten the wingnut up by hand preferably to ensure the gap is closed down. My SST wing had a gap because a washer was missing therefore not allowing the nut to tighten properly. This caused an exagerated left hand twist on take off, particularly at full power. Under the right conditions, the yaw was exagerated by a widening gap. I have now closed this gap and significantly reduced the yaw/twist on take off. Mine goes to the left rather than the right as in yours. I believe the difference is related to the torque of the engine which in the two stroke is to the left where as in the four stroke it is to the right. Bluey.

Well that does sound like what mine does. At the moment of lift off the pod starts swinging left. This causes the trike to start going left. As the yaw diminishes, the trike then tries to turn right as expected. Before I tightened up the hang point, the swing to the left was exacerbated considerably when you pulled in the bar a bit. The more it yawed left, the harder the roll right when it started to recover from the yaw. I'm not sure what causes the pod to yaw left at lift off. It also does it if you abort a landing just before touchdown. It however, does not do it in normal flight. Alf, when you say it yaws strongly sometimes into a crosswind, how strong a crosswind are you talking about? And do you think the yaw is worse than on other trikes you have flown? Thanks, Bluey.

Thanks Alf, I haven't tried the Dutch roll yet and don't plan to either. The yaw into the wind was expected but the amount was unprecedented for me. Let me assure you that it was way more than expected for the moderate conditions at the time. Unless I experienced some kind of thermal near the runway which produced a strong crosswind component just off the ground then the amount of yaw was over the top. When it happened, the only thing I had control over was the throttle so I focussed on climbing as you would. Before I tightened up the gap between the mast (which is the right one for the wing), the trike would yaw strongly at full throttle when you first rotated if you pulled the bar in for a bit of speed. It now seems much better but a little yaw to the left is still present. What I want to know is: Is this normal behaviour for the SST? Many of the people I have spoken to about this say it is now ok but most of those are going on hearsay as they have never flown one. Bluey.

Anyone with an SST wing have a yaw to the left at the moment of take off? Mine does and up till today it was quite pronounced. Yesterday I took off into a bit of a cross wind (about 10-14kts from 040) on runway 08 at ywol and was very strongly yawed to the left to the point where the trike base was now pointing around 40 to 50 degrees off track maybe even more. It quickly tracked off to the left before then beginning a strong roll to the right as it recovered from the yaw. After heading off to the coast to gather myself a bit before returning to land, I discovered a 2mm gap between the mast and the left inside of the bracket. Upon tightening the wing nut, I found that it was tight. Only to discover that there was a further gap between the washer and the thread on the hang bolt. After adding another couple of washers I found the wing nut now properly tightens and the gap is now closed. A test flight now reveals a fairly mild yaw to the left when taking off at full throttle one up as opposed to a more aggressive one before. Two up, the yaw is almost non existent now. I'm wondering whether I should bother taking it up to airborne for a further tune? The trike and wing has nearly 450 hrs. It otherwise flys very well otherwise. I had another experienced pilot go for a spin in it with me in the back today and also thought it flew nicely.

Thanks Alf, I've never found the carbys out by much either. I or anyone else I know have never checked a prop. I think I'm about to find out how mine is though. Bluey.

I forgot to ask Alf, when you checked the prop and carbys, did either need much if any adjusting? Bluey.

Thanks Alf, all the best with 001. Bluey

Thanks Alf, just out of curiosity, have you ever checked the prop pitch or the engines carby synchronization? Bluey.

After 440hrs of operation, I have detected two small cracks in the the U tubes on my XT912. These followed the detection of wear marks found on the exhaust lugs on both the front and rear horizontal pipes that attach to the muffler. In total, 4 lugs out of the 8 that attach the above mentioned pipes to the muffler showed wear. This is the second trike that this has occured to. In each case, no noticeable vibrations have been noticed. With the first trike, 2 lugs underneath the engine that connected the horizontal pipe to the muffler showed significant wear. In that case, the front U tube cracked. I don't think that it is a coincidence that wear on the lugs is independent of the tubes cracking. I believe that the cracking is probably due to a poorly aligned exhaust. When I pulled the latest exhaust apart for repair, I noticed that the horizontal pipes were very lose and not in contact with the muffler. This would have led to very large horizontal forces being applied to the vertical U tubes by the springs attaching the horizontal pipes to the muffler. Over a 440 hr time period, the stress and vibration that would have occurred has caused the pipes to crack and the lugs to wear. The other example of pipe cracking on the previous trike occurred at 453hrs (this was when it was detected). The ball joint of the horizontal pipes and the connecting socket of the muffler show no wear at all implying little to no contact. The joints that connect the U tubes to the muffler show some wear as expected as these parts are in constant contact (the wear is not at all excessive given the hours). From my perspective, it is clear that the exhaust components must be in contact when the springs are attached to elliminate the horizontal forces acting on the U tubes. All operators need to inspect the lugs for wear as this is an indicater that stress/vibration is present in the exhaust system. The remedy would be to loosen the exhaust bolts to allow all the exhaust parts to relax and hopefully elliminate the stress. With the previous U tube failure, an exhaust speciallist was able to weld it but unfortunately, the part didn't even last 50hrs before hairline cracks were noticed in the heat affected zone of the weld. It was suggested that placing a plate over the exhaust would be better but the exhaust specialist claimed that this was a no better solution than welding the crack. He also stated that he strongly believed that the original cracking was caused by prolonged and severe stress on the parts. No other parts of the exhaust or engine mounts show any evidence of excessive stress. Bluey

All the best to you Paul. Very glad your still with us. Bluey.

Thanks David, anyone know if the airfield is still closed or if the event is still running? Bluey.

Yes, absolutely. I'm assuming a phone call to the owner or operator would have identified the risk to an aircraft at this time? Bluey.

I hope we have a measured responce but given the potential for disaster that was only miraculously avoided I doubt it. I don't see the airfield being permanently closed from this as I don't see a significant risk to anything else when the event is not running. On a different note, was this the first attempt at landing for the aircraft in question? The reason why I ask is that I have assumed it was. This makes sense as I can understand the ferris wheel being missed the first time by both pilots but not on subsequent fly bys. Given that they didn't see it, why not? Especially considering it is quite clear in the photos. All I can think of to explain this is that glare caused by the overcast conditions made the relatively thin metal structure difficult to spot. If I'm not mistaken, it is a white structure. Bluey.

I agree with you David. The rules about operating in and out of an ALA are pretty clear from a pilots view point. However, if the operators see a risk as obvious as that and they ignore it because they can claim it is not their responsibility then they can still be deemed negligent. From the photos, the ferris wheel is very close to the runway line. If I were the operator and I was seeing aircraft fly at low level past one of my ferris wheels day after day I'd be very worried about my liability if some pilot got it wrong. A court will not accept " I saw the danger but didn't think it was up to me to do something about it " as an excuse. Each party has a duty of care. If a good barrister can establish that the operator was aware of the risk and did nothing about it, then they are in trouble. Either way, I'd be surprised if the event runs again next year in the same place. If it does, I expect the airfield will be closed for the duration. Bluey.

I can assure you the person who approved this event will get a legal grilling! From what facts I have read so far, there is a legal case to be answered by the organizers. Both the pilots and the parents of the children have a claim. Bluey.

Nothing that large should be that close to the end of a short runway. If the organizers of the carnival insist on holding the event that close to a popular airfield, they should insist on the closure of the airfield. No excuses about it. The organizers have a duty of care to the patrons of their event to do a proper risk assessment and take the necessary action to ensure safety. What if an aircraft has an efato? From a legal view point, the organizers have been negligent!

What I want to know is whose bright idea was it to put a ferris wheel that close to a well known airstrip in the first place? An obstruction of that nature, under the right conditions (overcast and gloomy) would make it hard to see from the air. Remember, it wasn't one person that did not see this thing, it was two. Both are pilots. That says a great deal about its visibility. I found its thin metal structure difficult to spot in the photos when up against a bright sky. Glare from a bright background would have made it difficult to spot when moving at high speed in the short distance from runway to obstruction. Someones arxe should get kicked hard for this one and I am not inclined to blame the pilots at this stage. Bluey.

Thanks Alf. Bluey

Still for sale. Please feel free to call or email lgdiscala@bigpond.com for more information. Bluey

Hi Alf, did it require constant input to keep it flying straight with the right wing down? Or was it just a torque effect causing the base to torque to the left as expected at higher engine revs. This may well explain the right wing down observation. I will probably give it a go when I have a few more hours on it. At the moment I have the trimmer disabled as it produces too much back pressure and makes it harder to fly at more than 65kts. With it disabled, it is not too hard to get to 75kt in level flight. Do you know if there is a way of adjusting the pitch pressure with the trimmer connected? Bluey

Has anyone moved the hang point of their sst to the front hole? I'm thinking of tying this at some stage so I'm wondering about other peoples experience. I expect that it would end up trimming at about 67kts hands off and it would be even lighter in pitch and more stable in turbulence. It would mean using the trimmer to slow it down a bit for take off as mine has a yaw to the left if you pull the bar in past trim when you first get off the ground. At all other times it seems to behave itself quite nicely. Bluey.

The grey looking paint on the tubing is a powederkote colour made by DULUX. It is a standard colour known as APO GREY. I just painted small patches of my 912 to cover up small areas of developing rust. For some reason, the painted areas seem to rust even though I can't see any breaks in the paint.

thanks John

Does anyone know the paint colour Airborne use on their microlights? All I know is that it is not white. It looks like an off white or light grey to me. If anyone knows the name of the actual colour so I could just go out and but it, that would be great. I am looking to paint over a few small spots of rust that appear under the painted metal parts. Spraying the affected areas with an appropriate lubricant doesn't seem to do much. Bluey

Airborne XT912 Tundra with Streak 3 wing and GRS chute, fly's beautifully at 56kt hands off, includes training bars and tall windscreen, prop net and mud flap for the front wheel, chatterbox intercom with headsets, vertex 220 radio with V rabbit antenna on kingpost. Excellent coms, no accidents, 595 hours total time with complete log books. Everything in excellent condition and always kept rigged in a hangar. All servicing recently performed. Great touring aircraft that has delivered many fantastic memories. A reluctant sale. Asking $40000. Hangard at Albion Park, NSW (YWOL) Call 0415530939 if interested Bluey