fallowdeer

Give it a rest Nev. Another completely unsubstantiated sweeping generalised negative comment from you about the 912 series. 50,000+ mostly happy users must be all wrong aye….

Gidday James. Our experience has shown with all taps on the tanks often empty at different rates, ending up with surprisingly different amounts in each. The theory is that this is caused by slightly differences in internal pressure from variations in the vents. If I was to build again I’d install cross venting. So I never fly with all open, the last thing I want is a little bit of fuel in four tanks. I’ve done a lot of long trips and I just run the outboards dry as I described above. With each tank holding 36 litres and burning around 16.5 an hour at cruise I find I get about 1 hour 40 minutes out of an outboard tank. The difference is the fuel returned to the starboard inner.

ZK-XBD recently converted from piston power to turbine here in NZ by Andrew Vincent, an airline pilot and engineer.

Hi James When my aircraft was inspected by the CAA they pored over the fuel system in great detail. As the POH and the build manual contained no information about a four tank system I had free rein on the design. As previously noted lots of pitfalls exist in the operation of a multi tank system so I had created the attached document and included it in the POH. This seemed to alleviate the regulator’s concerns. I frequently start up with all fuel valves off at the manifold looking for the low fuel light to come on after using about 100ml of fuel this testing the system as against the button on the panel which is only a bulb test. From experience in normal cruise I’m able to drain any tank completely with the exception of the R/H inner that the return goes to.

I pretty much copied Mark Kyle and IBob. . After 140 hours in nine months, I’m really liking the flexibility of having four individually valved tanks.

Each to his own. My opinions based on direct observations and conversations with probably the two most experienced 912 engineers in NZ, one of whom has been selling and servicing 912s for well over twenty years.

A 2000hr 912 that had those hours piled on quickly in a flight school while being well maintained is likely to be a better bet than a 12 year old model with 350 hours from what I’ve observed.

AC90-89C. Minimum fuel flow for pressurized fuel systems 125% of maximum consumption rate, 150% for gravity. A 912ULS will consume @ 28l/hr full throttle so you need a minimum of over 40l per hour, my build delivered over 60. This test will need to be notated in the logs if your paperwork requirements are similar to that required in NZ, which are basically copied from the US FARs.

By crikey reading this thread just makes me so grateful that every one of the thousands of times I’ve hit the starter on a 912 over the last fifteen years or so it’s actually worked…….

What are you building Lyndon?

Plenty of adverse yaw in a Savannah but the Dynon autopilot I installed in my build performs beautifully.

Nah Perry just a few bits that have fallen off in flight over the years if that counts..😁

Gidday Bryan I’ve got about 1000hrs in Savannahs, roughly 850 in mine and the rest in six or seven other machines. Every one of them had insufficient trim range to cover the full speed range from 35 to 90 knots. It’d be very tiring to have to hold forward stick in cruise so in my opinion the tab on the elevator should be adjusted so you’re just on the verge of running out of forward trim at maximum cruise power. That way you’ll minimise the rearward stick force you’ll have to exert (As mentioned by IBob) when flying at the other end of the speed spectrum, around 35knts short final on a STOL approach. Peter

Gidday Marty A couple of places over here make these for about $1200NZD. Heaps of nice features. Not sure if they have a pattern for a 701, this fits my S perfectly.

Pretty sure the TT22 doesn’t have a serial output which you would need to integrate to the Skyview . ( TT 21 doesn’t and they are identical AFAIK except for output power) As has been noted before you can’t just hook up any GPS even though it might be format compatible and expect to be compliant for controlled airspace.