Bluey

Well it seems as though the oli pressure issues I am having just won't go away. After a week of no flying, the oil pressure was zero for about 10 sec after a cold start. I did all the usual things and had the skydat turned on. I burped the engine about (8 - 10) rotations of prop. I even turned the prop over without the ignition switches on and still about 10 sec of zero pressure. The problem is not as bad when I fly more frequently but it still occurs. As stated in previous posts, the oil pressure rises quite quickly when the engine is warmed (less than 3sec of low pressure at start up). I've spoken to Wal at Bert Floods and he suggested attaching an analogue dial that bipasses the skydat to see what is going on. I've ordered one and will get it tomorrow. If it is a real pressure problem, Wal hinted at possibly opening up the engine to see what is going on. I mentioned that the operations manual suggested that the pressure needs to be above 2 atmospheres within 10 sec for normal operations and Wal was still concerned and suggested that the issue needs to be investigated. Any thoughts and ideas would be appreciated. Bluey

Airborne are looking at replacing the 2 stroke trikes with HKS four strokes. I spoke to them about it a while ago and they confirmed that they would be rigging a trike with one of these engines for testing. Bluey

Thanks for all your replies everyone. Very educational. Bluey

I also forgot to mention that I have lately been turning it over on the electrics for about 5 seconds or so before flicking the switches. This helps circulate the oil and reduces the low oil pressure warning time. I don't like doing this for too long out of fear of flatening the battery.

I turn the prop over about 10 revolutions at the start of every days flying. I have the oil cap off and listen to the burping. Being an airborne trike at 2.5 years of age I think the design is the same as all other airborne trikes. Having said that, I'm not sure if the tank is below the sump. It probably is. Bluey.

Finally got round to replacing the oil pressure sender unit and while the new one is producing quite stable pressures that are higher than the older unit, I am still seeing low pressures at start up with a cold engine. Don't know if it is significant but the warning light flashes and the pressure is below minimum for around 5 seconds or so at start up. As I said it only happens when the engine is cold when the engine has sat for a day or more. When the pressure does rise, it rises quickly and goes to around 5.8psi or so. During cruise it hovers around 4.0psi or even higher. A start up from a warm engine sees low pressures for a second or so. What's more is that I checked a friends 912 with lower total hrs than mine and strangely his reads a pressure when engine is off. This has to be a spurius reading. Hi warning light came on for about 2 seconds or so and the pressure rose a little slower. His also warmed up at about 3.3 psi and stayed at about that level during flight. Any thoughts?

Let us know when it arrives heldering, as I fly to Moruya quite regularly from Albion Park. I'd love to check it out. I understand that yours is the reflex 12 (12.5square metre wing)?

If the dollar stays high, they will be very competitive with the airborne 912's. I wonder if Airborne will go down the 912 ULS road and build a smaller faster wing to compete with the revo?

Yep, my mistake, it is the evo trike made by evolution. I heard a rumour that one was down in Moruya and that the new owner has his black streak 3 912 up for sale right now. I'd love to check it out when I'm next in Moruya. Bluey

Has anyone test flown one of the revolution trikes? The adverts seem really good. Are they as good as they are cracked up to be? The local importer has them priced at about the same as the airborne product. Based on the adverts they seem a better product than the best airborne has to offer. I wonder if this will have an impact on future airborne products? Bluey:book:

After removing the offending coolant hose, I was able to confirm that it is just fuel hose. Airborne have or had a habbit of using very low quality fuel hose on their new trikes. After about 50 hrs or so they would start to crack and so need replacing. The fuel hose they have used for their carb heating is the same low quality crap. I hope they have changed to a better fuel hose in the last few years but judging from the state of the fuel hose I recently saw on a trike built only in the last year, I think not. Fuel hose is not that expensive! Bluey.

Hi Scott, it was only one mag that temporarily failed but I don't know for sure which one. I think it was the second switch but I didn't get to check this because the engine shut down before I could systematically fault find. This I am sure of because I recall the rpm drop when I switched one of the switches off at shut down (I always do a mag check before shutdown every time). Anyway, I have spoken to some pretty experienced people who have told me they have had similar intermittent problems and have just ignored them with no long term issues. This doesn't mean I would do the same but this has been the experiences of others. In the case of the CHT issue I was having, I noticed the connection to the probe was a little off centre. I moved the connection for better contact and have since flown more than 5 hours with virtually identical CHT's. I will keep a close eye on the temperatures in any case. Bluey

Thanks David, that sort of thing will wreak havoc with these sorts of sensors every time. Bluey

Looks like the elecrical lead was a little loose. I jiggled it a little and now it is pretty much reading the same temps on both cylinders. Bluey

Maj, I bought the Narva single throw switch (12V, 20A) which are apparently the same as those used by airborne. Bluey

David, I always do a pre take off check to 4000 rpm when the oil temperature is above 40 degrees celcius. The shutdown check is at idle and is just an extra mag circuit check that really is not required but I do it anyway. Bluey

After a long flight yesterday, I went to shut down the engine and one of the mag switches failed and the engine failed to shut down. I flicked the switches on and off 3 or 4 times before the engine succesfully shut down. After a little while I restarted and tested the switches on at a time and they both worked fine. I did this numerous times. I test flew and landed and the engine shut down normally. Before each shut down, I normally test each switch to ensure proper working order. Anyone ever have a problem like this? I have heard of a few instances of random failures that never repeat themselves. I have purchased two replacement switches but have been told that unless the failures happen again then it might be pointless replacing the switches. I have even heard of a couple of instances of failures on a new aircraft. Bluey.

I need to replace the thin coolant hoses on an xt912. I believe these are the hoses that airborne puts on the engine that are for the carbie heat so they are not a standard 912 hose. I've already checked with Bert floods and they don't know anything about them. I believe that the hoses in question are simply 1/4 inch fuel hoses. Can anyone confirm that? They are definitely carrying coolant. Bluey.

Hi, during a flight this morning, I noticed that one of my CHT temperatures was lagging behind by about 10 to 20 degrees from the other one (912 UL). The one that was lagging was quite variable in that it was always behind the other and changing quite quickly by about +/- 5 degrees in a matter of seconds. At the same time the other CHT was very stable. This to me indicates a failing probe not a real problem (hopefully). I wouldn't expect the CHT to vary quickly at normal cruise RPM. Anyone had any similar experiences? Bluey

yeah, I can second Mc Guyver's comment about the grease. It works brilliantly. I have just recently had to do this after repairing a crack in my exhaust. Bluey

Thanks everyone. I've done the balancing and it does seem to be smoother but the difference is quite subtle. I will make sure to check it according to the manual. Bluey

Thanks for the advice facthunter but the engine is the 912. I will go the extra mile to get the idle balanced as close as possible too. Bluey.

Hi, Just did a carbie sync for the first time and was interupted by some weather so couldn't quite finish it. I used the dial system supplied by airborne. Ifound that there was indeed a significant difference between the carbies at around 4500rpm (about 4inches of Hg at this rpm according to the supplied dials, 4 divisions). Anyway , after a small adjustment, I managed to get it very close to balanced. However, at idle there is a difference of about 1 inch of Hg (1 division). Just wondering if it is nescessary to make any adjustment to the idle (which is currently sitting at 1850rpm) if the the carbies are quite close anyway? Bluey

I have ordered the carbie syncing kit from airborne and plan to check the carbies before I fly again. Attached are the photos of the damage done to the exhaust lugs by the spring on the underside of the exhaust. This spring is the most difficult to check properly in preflight. Now that I know exactly what to look for, I don't think I will miss [ATTACH]12740.vB[/ATTACH]that sort of wear again. Airborne are pretty sure that the damage done is from out of sync carbies. I'll find out pretty soon if that is true. Bluey[ATTACH]12739.vB[/ATTACH]

While my EGT's show a small difference, the CHT's are usually very close typically within 5 - 8 degrees. When the plugs are new the are generally within 5 degrees. Bluey