Re: C172 auto pilot

PPL Training

C172 auto pilot

James Marshall 24/07/2003, 10:25 PM
Hi,

I was woundering, I know there is an auto pilot in a Cessna 172 but when would you use it?

Would you use it just for long jurneys so that you don't have to keep trimming out the pitch.

Is there anyone out there that fly's the 172? Whats is it like to fly compare to the 152?

Regards

James

Re: C172 auto pilot

Andrew Sinclair 25/07/2003, 11:07 AM
I am in a C172 group and we don't have an autopilot in our aircraft. Maybe the modern ones do I am not sure about that. For VFR flying < few hundred nautical miles I probably won't get any advantage and wouldn't use it.

When the aircraft is in correct trim in the cruise you shouldn't have to keep trimming out any steady elevator control pressure. Departures in altitude of less than 100' can be recovered by a series of zooms and dives if necessary. For larger departures power+attitude change will recover the lost/gained altitude then re-trim. The performance of an aircraft is a function of attitude and power setting and if these don't change then you are left with thermal effects which can be captured and recovered quite easily.

I have flown both and the C172 is larger, has more weight carrying capacity, cruises about 10kts IAS faster and doesn't feel so cramped. There are, I am sure, other differences.

Re: C172 auto pilot

Rick Larkin 29/07/2003, 9:57 AM
I fly a 172RG and it has a autopilot on it. Our plane also has long range tanks so we have a little over 7hrs range with 2 people on board so on flights this long it certainly does come in handy! Up high, above 5000' or so you don't need to adjust pitch much because the air is usually smoother, once you get it trimmed out right and dont expect it to hold the altitude exactly it really is a help. In regards to comparing the two types, the 152 is a different plane and I don't think it's fair to compare them, they aren't in the same class. Speaking of the RG version of the 172, we consistently get a cruise close to 140kts up high and it has fantastic short field performance when heavy.