Buying a 172M

[milleR]

A friend of mine is considering a 1976 Skyhawk but I’m pretty out of my depth with these things. This is what he received from the owner:

Hi,
Thank you for contacting me about the 1976 Cessna 172 M. All compression is good, has a King 150 audio panel, 4 place intercom, (2 ) MX 300 Nav Com radios, Stratus ADSB In-and-out Transponder, has three Brand new Tires, LED landing lights, all the log books since new , Oil reports on all services in the last 2 years that me and my husband owned it, New Muffler, New Brakes. It was maintained Very well. If it needed something, my husband replaced it. TT: 4738 Hours, SMOH: 2435, STOH: 440. The price is firm, $23,400. I am selling it because my husband passed away 2 months ago (he suffered a heart attack) and I need the money to pay my daughter's college. We decided to sell the house and we moved with my parents trying to start a new life.
Let me know if you are interested in buying it or if you have any questions. I also attached more pictures!
Thank you,

High time engine but the top isn’t too bad ... what do you guys think? The pics look really clean.

 

[jynxyjoe]

Had an M model for a couple years. The landing/taxi lights will rattle and die, but they'll only die at light on short final. Suggest taping flashlights to cowl vis a vis rick sanchez spaceship/timemachine

 

[z987k]

Had an M model for a couple years. The landing/taxi lights will rattle and die, but they'll only die at light on short final. Suggest taping flashlights to cowl vis a vis rick sanchez spaceship/timemachine

That's why everyone, including this one, have switched to LED.

@milleR that's starting to get high time on the engine, and rather weird that you would only do a top overhaul at 2000 hours. Probably didn't have the money for the full engine. I'd budget for a complete overhaul in the next 600 or so hours. The 150hp O-320 is pretty great motor though. The 172M had the O-320-E2D iirc, great motor and still had the 40 degrees of flaps(awesome). The 172N I think was the first year of 30 degree flaps and had the only O-320 that is crap, the H2AD(all the H models). (don't buy an N). Price is pretty good though. Seems to be a pay later kind of deal with the motor, but the avionics sounds like it'll be good enough for a long time.
Bring a boroscope and look everywhere for corrosion. Cessna didn't put anything on the inside of the wings until relatively recent, don't know what year that started though. If it's not, hopefully it's oozing corrosion x or acf-50, that stuff should be coming out of the inspection panels like something is leaking out of the wings unless it's just washed.

 

[jynxyjoe]

That's why everyone, including this one, have switched to LED.

@milleR that's starting to get high time on the engine, and rather weird that you would only do a top overhaul at 2000 hours. Probably didn't have the money for the full engine. I'd budget for a complete overhaul in the next 600 or so hours. The 150hp O-320 is pretty great motor though. The 172M had the O-320-E2D iirc, great motor and still had the 40 degrees of flaps(awesome). The 172N I think was the first year of 30 degree flaps and had the only O-320 that is crap, the H2AD(all the H models). (don't buy an N). Price is pretty good though. Seems to be a pay later kind of deal with the motor, but the avionics panels sounds like it'll be good enough for a long time.

Not sure if i remember my old flap settings. Is it possible the M had 40 or something crazy degrees? Been over a decade. I thought it had 30 but maybe not.

 

[milleR]

That's why everyone, including this one, have switched to LED.

@milleR that's starting to get high time on the engine, and rather weird that you would only do a top overhaul at 2000 hours. Probably didn't have the money for the full engine. I'd budget for a complete overhaul in the next 600 or so hours. The 150hp O-320 is pretty great motor though. The 172M had the O-320-E2D iirc, great motor and still had the 40 degrees of flaps(awesome). The 172N I think was the first year of 30 degree flaps and had the only O-320 that is crap, the H2AD(all the H models). (don't buy an N). Price is pretty good though. Seems to be a pay later kind of deal with the motor, but the avionics sounds like it'll be good enough for a long time.
Bring a boroscope and look everywhere for corrosion. Cessna didn't put anything on the inside of the wings until relatively recent, don't know what year that started though. If it's not, hopefully it's oozing corrosion x or acf-50, that stuff should be coming out of the inspection panels like something is leaking out of the wings unless it's just washed.

My thoughts on the engine as well, thanks

40 degree flaps are glorious

 

[z987k]

Not sure if i remember my old flap settings. Is it possible the M had 40 or something crazy degrees? Been over a decade. I thought it had 30 but maybe not.

The M had 40, I'm fairly sure the N was the first year of 30. The M has the AD for the placard not to slip with 40 degrees, which is debated ad nauseam among clueless flight instructors.

 

[z987k]

Oh, and sometime on the N model they went 28v, which tends to make electrical things cost more, and near as I can tell, didn't save a single ounce of weight.

 

[Roger Roger]

Oh, and sometime on the N model they went 28v, which tends to make electrical things cost more, and near as I can tell, didn't save a single ounce of weight.

I didn’t think they went 28V until the R model.

 

[jynxyjoe]

Oh, and sometime on the N model they went 28v, which tends to make electrical things cost more, and near as I can tell, didn't save a single ounce of weight.

If u stayed at 12 it would have been heavier. 28V makes Watts happy.

 

[jynxyjoe]

My thoughts on the engine as well, thanks

40 degree flaps are glorious

I think the 150 from 19 *mumble mumble" has something stupid like 44 or 45 just in case you wanna hover.

 

[z987k]

If u stayed at 12 it would have been heavier. 28V makes Watts happy.

I mean in theory, but have you looked at what the empty of an SP or later 172 is? It's ridiculous. Maybe they did save some weight in thinner wires, but 500% of it came back elsewhere.

 

[jynxyjoe]

I mean in theory, but have you looked at what the empty of an SP or later 172 is? It's ridiculous. Maybe they did save some weight in thinner wires, but 500% of it came back elsewhere.

Eh, i think youd be surprised if you sat down with the engineers where and how much you're saving. And as airplanes start sucking down more current you just cant stay at 12 or 24 (28), you're gonna be doing that 48 arc welder crap the mil does.

 

[drunkenbeagle]

I mean in theory, but have you looked at what the empty of an SP or later 172 is? It's ridiculous. Maybe they did save some weight in thinner wires, but 500% of it came back elsewhere.

In addition to weight, the smaller gauge wire probably cost a bit less. Adding that up across a few hundred airplanes, it might have seemed worth it. Or, they might have already done the engineering work at different voltages with it being a wash either way, but when they were sourcing parts (which are often ordered a year+ in advance), some weren't available reliably. Situations where common parts aren't available in quantity do happen. Quite a bit right now with the tariffs, in fact.

 

[trafficinsight]

I didn’t think they went 28V until the R model.

No the N was 28v and was the first year with preselect flaps.

N models should have 40 degrees of flaps too, unless they've had an STC gross weight increase or the 180hp conversion.

I'm not aware of any AD for no slips with 40 degrees, there is a note in the POH that says to "avoid" slips with 40 degrees of flaps but nothing bad happens, it just buffets a bunch.

Speaking of the 180 conversion... Do the 180 conversion.

Sent from my Moto Z (2) using Tapatalk

 

[jynxyjoe]

If you need slips with flaps 40 in a 172 I encourage that pilot to get recurrent and think more than 5sec ahead.

If it's that bad go around.

 

[z987k]

Eh, i think youd be surprised if you sat down with the engineers where and how much you're saving. And as airplanes start sucking down more current you just cant stay at 12 or 24 (28), you're gonna be doing that 48 arc welder crap the mil does.

You don't need to be an engineer to look up what copper weighs and to figure out minimum wire gauges. Also, not much in a cessna has a wire exceeding 15 feet or so, so resistance over distance isn't usually a factor. On a 15ft run the difference in weight between 24 and 20AWG wire is about .4oz.

 

[Roger Roger]

You don't need to be an engineer to look up what copper weighs and to figure out minimum wire gauges. Also, not much in a cessna has a wire exceeding 15 feet or so, so resistance over distance isn't usually a factor. On a 15ft run the difference in weight between 24 and 20AWG wire is about .4oz.

The wires are smaller enough to matter when you’re trying to add another one to an already crowded run. Also, since you’re running a 60 amp or so alternator in both cases you get twice as much power out of the 28V system which is nice when you go to add any electrical equipment.

 

[jynxyjoe]

You don't need to be an engineer to look up what copper weighs and to figure out minimum wire gauges. Also, not much in a cessna has a wire exceeding 15 feet or so, so resistance over distance isn't usually a factor. On a 15ft run the difference in weight between 24 and 20AWG wire is about .4oz.

Well, maybe I'm saying back to you what you're saying to me, but as the current grows between heat and weight your gonna be heavier than you think you are on those 12V systems, and while it may seem the same between two models, i wouldnt feel comfortable saying they are the same weights if i cant verify the seats are the same, the interior souns proofing didnt absorb the weight savings, that sorta stuff.

Even if you're just isolating two specific models, 12v is indefensible for current avionics demands.

No biggy though, buy me a bottle of something expensive and ill change my mind.

 

[DE727UPS]

I'd say that's a pretty good deal in spite of the engine time and old radios. I had an M model I ran to 2300 hours with no issues on auto gas.

 

[Roger Roger]

No the N was 28v and was the first year with preselect flaps.

N models should have 40 degrees of flaps too, unless they've had an STC gross weight increase or the 180hp conversion.

I'm not aware of any AD for no slips with 40 degrees, there is a note in the POH that says to "avoid" slips with 40 degrees of flaps but nothing bad happens, it just buffets a bunch.

Speaking of the 180 conversion... Do the 180 conversion.

Sent from my Moto Z (2) using Tapatalk

I’ll be danged. I flew a few Ps and maybe a Q way back in the day but I never realized they weren’t 12V. You sure it was standard and not a factory option?