Friday, May 11, 2007

Plastic Engine Cessna 172

You're getting bored of DA40 planes ? Lucky you, I will now post about a C172 in which a plastic engine has been retrofied. Unfortunately for my own experience, it has classical instruments, and is VFR only. I think you need to know that I converted to C172 by the very end of last year, and I never flown a classical engine C172 before (except as PAX...).
Nothing special in engine handling compared to the DA40, as it's the same powerplant, same FADECs, and nearly same AED / CED. On this particular Cessna, the fuel quantity indicators are still the old gages, they are not integrated in the new indicators. One noticeable difference in engine management compared to DA40 is the cool down time. After landing, you have to run on IDLE power for two minutes with a DA40, whereas you can stop the C172 immediately. This is probably due to the much larger air intakes in the C172.
For C172 classical engine pilots, a new issue will raise: fuel management. I'm sure you all manage fuel properly in terms of quantity, but with the diesel you have to care about balance as well, because the new fuel system does not have a "both" position for its fuel selector, so you'll have to switch tanks periodically. If you fail doing so, you riks a fuel imbalance, but also temperature problems.
The particular C172 I fly now had the long range tanks options, but the tanks have been reduced with the plastic engine retrofit. They have now a capacity of 20 USG each, so an autonomy of about 6h40... Should be enough for most operations.
When comparing the performance graph, it seems that the diesel version is slightly less performant below 5000ft, but then the turbo advantage makes the difference. On a normal day, I could once climb from 1'5'00 ft to 13'000 ft in less than 25 nautical miles.
One important restriction concerns the TDI engine bad reaction to fuel starvation. The high pressure pump can be damaged it if runs witouht fuel for more than 15 seconds. As a consequence of that, long out of balance situation could lead to severe engine damage. I know at least one case of pilot who loss engine power during a long side-slip. The club management answered to this issue by prohibiting side slips...