2006 Cessna 172

[Adam_H]

Hi guys, just after a bit of clarification here if possible, on the website below it has the Lyoming IO-360-L2A as 180HP but on Wikipedia (reliable source) lists it has it as 160HP. I'm sure there are people that know much more than I do here, so just wondering if there is a simple explanation here.

 

Also, the website below has Payload - 577lbs. I'm right in thinking that's how much weight of passengers and luggage you can have with full fuel tanks right? Which doesn't really leave a whole heap. I know a lot of people say that Cessna's are workhorses and can usually go over their weight but that seems pretty risky to me.

 

2006 Cessna 172S Skyhawk SP - Plane & Pilot Magazine

 

Thanks in advance!

 

 

[facthunter]

The 172 was generally only able to carry 3 . It's not an overpowered plane. Stick to the charts especially where you are at altitude on a warmish day where you might be lucky to lift 2 and 1/2 fuel. Nev

 

 

[Adam_H]

The 172 was generally only able to carry 3 . It's not an overpowered plane. Stick to the charts especially where you are at altitude on a warmish day where you might be lucky to lift 2 and 1/2 fuel. Nev

Hey mate, yeah it does seem that way. Is that how you read that page too? The payload being the weight the 172 can carry with full fuel?

 

 

[facthunter]

AUW is basic weight to which you add everything including fuel load. For max allowable You have a straight out structural one and one that depends on the environment the plane is flying in. Ie for take off.. Density altitude, wind, runway length and whether it's wet or soft and slope and near obstacle clearance. You might have to play with flap setting to optimise all that. It should all be in the POH for the type which gives the actual basic weight and index for balance purposes. If the prop has been replaced or cut down or any engine mod or the engine is down on power it won't be accurate. Older planes with a few dents etc don't perform as well either. Nose heavy reduces performance as there's an extra load on the elevator that counts the same as an actual weight, but that's not considered in the charts. Nev

 

 

[djpacro]

The payload being the weight the 172 can carry with full fuel?

That is what it states on that magazine's website for the particular set of numbers they are quoting. You'll probably find that a typical empty weight is higher than quoted by the magazine however.

[fallowdeer]

I always thought All Up Weight was technically the total weight of airframe, fuel, crew, load etc at any point in time.

 

Often used interchangeably (if in error) with Maximum Takeoff Weight.

 

 

[facthunter]

AUW is total weight at any defined point of time. You can typically have max taxi weight, max takeoff weight and several max landing weights defined on configuration (Flap setting) that are based on AUW and are structural. The take off limitations may be structural (which you can't normally exceed without a specific dispensation, Ferry flight perhaps) or related to the physical conditions the plane is in which may further reduce it ( elevation, Temp, QNH ,runway length and slope. Wind component). Landing distances required imply a limit on landing weight that could be a restriction. There are also approach climb limits.( Performance for go around and clear obstacles). and other special procedures..Some takeoff charts don't show any figures for temps over 42 degrees C so if it's hotter you can't go legally. You can't legally extrapolate off the chart..

 

So it can get complex, but the principles are all the same. whatever the plane. Its performance must meet the demands of the situation Your charts enable you to confirm it's safe. .Nev

 

 

[mike_perth]

The 172S (marketed at the 172SP) is 180hp (From factory) the 172R that preceded it is 160hp - the R model has a lower MTOW than the S version by around 50kg from memory.

 

I frequently fly the 172SP 4 up - but it has to be short flights as you really cant carry much fuel (if you are all slight builds then 90ltrs is usually max fuel to give you around 1.2 hours with appropriate VFR reserves)

 

 

[Adam_H]

The 172S (marketed at the 172SP) is 180hp (From factory) the 172R that preceded it is 160hp - the R model has a lower MTOW than the S version by around 50kg from memory.I frequently fly the 172SP 4 up - but it has to be short flights as you really cant carry much fuel (if you are all slight builds then 90ltrs is usually max fuel to give you around 1.2 hours with appropriate VFR reserves)

Hey Mike, So a fully loaded 172S with full tanks only gives you about 1.2 hours flight time?

 

 

[Nobody]

The 172S has a 180 hp engine in it according to the POH I have in front of me. If you look at the lycoming website you can see that the io-360-L2A has both 160 and 180HP options. It is probably due to the max RPM. I think some engines in other aircraft had a reduced max rpm of 2400 rather than the 2700.

 

The useful load is listed on your link is 895 lbs. Over time the Cessnas have got heavier, both empty weight and gross and with bigger engines. The M model and earlier were only 150 HP and had an emplty weight of about ~1400lbs but the MTOW was only 2300 so similar useful load.

 

The 895 lbs useful load does work out at 577 lbs with full fuel but that fuel will last you over 5 hours. If you want to use it as a 4 seater you have to leave some fuel behind. If you want to fly for 3 hours you will need about 200lbs of fuel(with reserve) and so will have about 695 lbs for people, which works out at just under 80kgs per person. An 80kg person is going to want a leg stretch after 3 hours in the back of a 172!!!!

 

There are very few GA aircraft that you can fill all the seats with big adults and top the tanks right off.... If the designer did that why wouldn't they have bigger tanks for when you want to fly with less people.

 

 

[Nobody]

Also have a read here for more details about the specs of the different models:

 

The Cessna 172 - Models

 

 

[Adam_H]

The 172S has a 180 hp engine in it according to the POH I have in front of me. If you look at the lycoming website you can see that the io-360-L2A has both 160 and 180HP options. It is probably due to the max RPM. I think some engines in other aircraft had a reduced max rpm of 2400 rather than the 2700.The useful load is listed on your link is 895 lbs. Over time the Cessnas have got heavier, both empty weight and gross and with bigger engines. The M model and earlier were only 150 HP and had an emplty weight of about ~1400lbs but the MTOW was only 2300 so similar useful load.

 

The 895 lbs useful load does work out at 577 lbs with full fuel but that fuel will last you over 5 hours. If you want to use it as a 4 seater you have to leave some fuel behind. If you want to fly for 3 hours you will need about 200lbs of fuel(with reserve) and so will have about 695 lbs for people, which works out at just under 80kgs per person. An 80kg person is going to want a leg stretch after 3 hours in the back of a 172!!!!

 

There are very few GA aircraft that you can fill all the seats with big adults and top the tanks right off.... If the designer did that why wouldn't they have bigger tanks for when you want to fly with less people.

Hey mate, great detail there! All makes sense and makes the 172 a little more attractive. Thanks a bunch and I will definitely have a look at the link you put up to! Cheers!

 

 

[planesmaker]

My 4 seat jab is good for 355kg better performance than C172 while using half the fuel.

 

 

[Nobody]

The Jab430 does compare pretty favourably to the Cessna at a lot less cost to buy and operate. Lets do a comparision to see the difference. Imagine that you and some mates wanted to fly from Sydney(YSBK) to Coffs Harbour(YCFS), 255 nm away. How much weight can each haul? How much fuel will each use?

 

Cessna 172S (Working in the POH units)

 

Empty Weight 1660 lbs

 

MTOW 2550 lbs

 

Cruise speed 119 knots at 2600 rpm @ 8'000 feet =9.4gal/hr(~36l/hr)

 

The 172 will take 2.15hours to get there + allow 0.25hr for climb and maneuvering and 0.75 for fixed reserve =3.15hours

 

It will therefore need to fill to 29.6 Gallons and expect all going well to land with ~7Gal remaining having burnt 22.6Gal(85L)

 

The fuel will weigh 177lbs leaving 713lbs (324kg) or 4, 80kg people and a towel each(and nothing more)

 

Jabiru 430

 

Empty Weight 370kg (This is the value for the 230 which except for the seats should be the same)

 

MTOW 700kg (The value for a VH registered one)

 

The jabiru 230 POH has scant cruise performance information however Jabiru mention a cruise speed of 120 knots using 24-29l/hr on their website.

 

The jabiru will also takes about 2.15hours to get there + 0.25 for climb and maneuvering and the same fixed reserve=3.15hours

 

If we use 25l/hr then we need to fill to 79l and expect to land with 19l having burnt 60L

 

The fuel required will weigh 56kg leaving 274kg for people (and towels), Your mates need to be under 70kg or one is staying behind.

 

The cessna can carry more (50 kg) but uses 25L more fuel to get there, with probably double the operating cost. Note that there is considerable variation between differing models of aircraft and the comparison would be different if we compared to 172R(less useful load) or a 172Q(more useful load) Also the jabiru, being experimental can be fitted with different engines, a 912 powered jabiru will be slightly slower but with a lower fuel burn. Also I think that in South Africa the Jabiru can operate at 750kg which means that there is little difference between the two.

 

 

[facthunter]

The only thing I would add to that is one owner I knew who found the heat in the Centre of Australia did limit it's lifting ability at times. (Jabiru 430). Cessna wings are noted for managing to get out of places on the limit of it's capability, better than most comparable aircraft and have one of the best (FOWLER) Flap system about ona light aircraft. The 182 is a very good plane and the 180/ 185 etc as a tailwheel if you are serious.

 

The Jab 230/ 430 is certainly worth looking at . Plenty of them go long trips well. Nev

 

 

[ian00798]

The useful load is listed on your link is 895 lbs. Over time the Cessnas have got heavier, both empty weight and gross and with bigger engines. The M model and earlier were only 150 HP and had an emplty weight of about ~1400lbs but the MTOW was only 2300 so similar useful load.

Of course the other thing that has statistically become substantially heavier from when the C172 was first designed and built is the self loading freight. I suspect that the useful load used to be much more useful back when your average adult weighed 75kg, not 90-100

 

 

[skippydiesel]

The Cessna 172 figures seem to be about right (I think I used to plan at 120 knots/32 lph, two lightweight pax). I did "move up" to a 172 Cutlass, that if memory serves me right I planned at 128 knots/35 lph

 

Just a wee bit sceptical on the claimed Jab 430 cruise performance & fuel consumption. No facts to back up my scepticism but I seriously question transporting 3-4 adults with 120 hp @120 knots with a fuel burn of 25 lph This might be the figures for an single anorexic pilot and partial fuel.

 

 

[Nobody]

Of course the other thing that has statistically become substantially heavier from when the C172 was first designed and built is the self loading freight. I suspect that the useful load used to be much more useful back when your average adult weighed 75kg, not 90-100

True, but the increase affects both the Cessna and the Jabiru equally. The ABS also put the increase at about 4kg over the last 20 years which means a lot of people are lying on the census:

 

4338.0 - Profiles of Health, Australia, 2011-13

 

Skippy, the Jabiru performance figures were taken from their website, the POH does not have much in the performance section and so could be influenced by marketing inflation but like you I don't know for sure. The jabiru airframe is a lot smaller and the wing a lot slipperier and higher aspect ratio, the cessna has rivets protruding from the wing and so it isn't unreasonable that it gets these numbers.

 

The main point to take from the discussion is that both aircraft will have to trade people for fuel over longer distances. You can't completely fill the tanks and fill all the seats. This is true of almost every aircraft even up to the large airliners.

 

The other point to remember is that the cessna is likely lugging around all the equipment to allow flight in IFR conditions and all that comes with that. Garmin G1000 + 2 nav radios plus vacuum pump + bigger alternator. This all affects the empty load and how much you can haul.

 

 

[ian00798]

True, but the increase affects both the Cessna and the Jabiru equally. The ABS also put the increase at about 4kg over the last 20 years which means a lot of people are lying on the census:

My intended point was that when the C172 was initially released, it quite possibly was genuinely a practical 4 person aircraft. These days it isn't unless you are very light on fuel. Also if you look at that graph with the average weights for the person coveraging flying age the difference is more like 6-8kg, and that's just in the last 20 years. The C172 was released 60 years ago. Even at a conservative 6kg per person weight increase, this is 24kg of extra weight, or 33L of fuel that can't be carried. That's basically an hour less range.

 

 

[skippydiesel]

I understand very well your collective arguments regarding fuel versus payload/pax - I was just pointing out that the figures given by Nobody for Cessna 172(s) seem to reflect my real world experience, where as the Jab figures quoted leave me somewhat unconvinced.

 

So, if I am correct, you are quoting real world performance for the Cessna 172 and "Marketing BS" performance for the Jab.

 

 

[planesmaker]

Skippy I have no problem doing 115kts @ 20lts/hr 700kg (355kg payload) with better climb than C172. Admittedly smaller inside but quite a capable aircraft.

 

 

[skippydiesel]

Skippy I have no problem doing 115kts @ 20lts/hr 700kg (355kg payload) with better climb than C172. Admittedly smaller inside but quite a capable aircraft.

It is not my intention to "bag" Jab's, just to point out that Jab, along with many other aircraft manufacturers, is somewhat prone to hopeful performance claims. (I am actually a "closet" admirer of the Jab airframe/think they could should have gone for a much better engine).

 

I just checkt Jabs claims for the 430/230 - 120 knots @ 23-29 lph (weight, temp, altitude, not specified). Make of it what you will. Payload (VH 355 kg) is truly amazing for such a compact aircraft. By my rough estimates, this allows for full fuel, 80 kg x 3 adults, plus about 15 kg luggage. Mind you at max weight, I would expect to see a higher fuel burn (30+ lph ??) and probably well below the hoped for 120 knot cruise (105 ??).

 

 

[facthunter]

Are you talking a 230 or 430?. While The drag won't vary for a given weight, you will pay for any extra weight you do carry. Rivets on a wing don't affect the drag much if they are more than about 1/3rd back from the LE. Nev

 

 

[IanR]

We have four Cessna 172s - and the weight carrying differs significantly depending on the model. As mentioned the S model has 180HP and the R has 160. They are identical engines with only the prop allowing the 180 to be achieved. We recently converted one of ours from 160 to 180HP. Tach, Prop and airspeed indicator were the only significant changes. The 180HP ones will indicate about 120 knots at cruise and 2500ft

 

For reference, here is some approximate data on ours

 

172S G1000 - empty 801, max 1156

 

172S - empty 768, max 1156

 

172R with 180HP - empty 764, max 1156

 

172R - empty 759, max 1113

 

 

[mike_perth]

I am not advocating the use of or removing the onus on the pilot in command to do their own weight and balance calculations but I fly an aircraft from a club and they have made available a weight and balance for the aircraft in a very handy self calculating excel spreadhseet - its available at the following page - Flight Manuals – Curtin Flying Club the one you'll want is the weight and balance excel

 

As mentioned above and in the spreadsheet it is the pilots responsibility to ensure the data is correct and the weight and balance is calculated as per the POH but I find this is a good tool to assist me in my flight planning