Getting those four adults into a C172...
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Hey Javelin,
You know we crossed paths around the drop zones many times but Danny got us licked while out in the States. Got 5 jumpers into the 182
Thankfully impossible with my size and wearing that insulated Sheila Cooper suit
Rob
You know we crossed paths around the drop zones many times but Danny got us licked while out in the States. Got 5 jumpers into the 182
Thankfully impossible with my size and wearing that insulated Sheila Cooper suit
Rob
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Reims F172
Here are my calculations for a Reims Cessna F172M
Weight (lbs) x Arm (Inches) = Moment (Pound Inches)
Basic Weight: 1488.9 x 38.87 = 57873.54
Row 1: 364* x 44.00 = 16016.00
Row 2: 308** x 73.00 = 22484.00
Fuel: 114*** x 48.00 = 5472.00
Baggage Area 1: 25 x 95 = 2375.00
* 13 stones x 14 lbs/stone x 2 people = 364lbs
** 11 stones x 14 lbs/stone x 2 people = 308lbs
*** 19 USG x 6lbs/USG = 114lbs
Totals
Weight: 2299.90 < MAUW of 2300lbs
Arm: 104220.54/2299.90 = 45.32 inches < Max Aft Moment of 47.5 inches according to POH/FM
Close, but within limits with baggage placed in Baggage Area 1 and a maximum of 25lbs and not 28lbs.
Weight (lbs) x Arm (Inches) = Moment (Pound Inches)
Basic Weight: 1488.9 x 38.87 = 57873.54
Row 1: 364* x 44.00 = 16016.00
Row 2: 308** x 73.00 = 22484.00
Fuel: 114*** x 48.00 = 5472.00
Baggage Area 1: 25 x 95 = 2375.00
* 13 stones x 14 lbs/stone x 2 people = 364lbs
** 11 stones x 14 lbs/stone x 2 people = 308lbs
*** 19 USG x 6lbs/USG = 114lbs
Totals
Weight: 2299.90 < MAUW of 2300lbs
Arm: 104220.54/2299.90 = 45.32 inches < Max Aft Moment of 47.5 inches according to POH/FM
Close, but within limits with baggage placed in Baggage Area 1 and a maximum of 25lbs and not 28lbs.
Last edited by Alan O'Brien; 15th Oct 2003 at 22:19.
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MikeC / drauk - thanks for that - I'll go and play about with those numbers and get the basics of the spreadsheet checked, then verify the numbers against the tech log on Friday. I'd guessed at an arm of 67 for the rear seat, so I may be helped by the extra 7"! 
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Thanks Alan,
Nice confirmation of my figures which are very close (except the Pilot's row arm is only 37").
Which leaves me with the problem of the max aft arm...
I carefully reread the limits in the POH, and my max aft figure was actually the max forward figure
Max aft is actually 47.24", so in theory - 4 reasonable size adults as per my theoretical loading, and a bit of baggage is legal
.
Another way of looking at it, which takes the plane to the limit is:
same passenger weights - no baggage - fuel at tabs
All is not lost. I guess it's back on Atkins for me...
Nice confirmation of my figures which are very close (except the Pilot's row arm is only 37").
Which leaves me with the problem of the max aft arm...
I carefully reread the limits in the POH, and my max aft figure was actually the max forward figure
Max aft is actually 47.24", so in theory - 4 reasonable size adults as per my theoretical loading, and a bit of baggage is legal .Another way of looking at it, which takes the plane to the limit is:
same passenger weights - no baggage - fuel at tabs
All is not lost. I guess it's back on Atkins for me...
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Ah, you've all beaten me to it, and after I spent last night working through the W & B data for all the 172 marks I had data for (M, N, P, R, & S) 
Anyway since I've done it you're going to get it 
I initially thought KCDW might have been looking at the aft CG limit for the Utility category, rather than the normal category, but these are a bit further back (~41")
The CG envelope on the marks of 172 I looked at seem to be pretty similar, albeit with different maximum AUWs. Forward CG limit is 35" upto about 1950lbs, then a straight line to either 38.5 or 39.5 (depending on mark letter) at MAUW, with the max reaward at 47.3"
According to my calculations you'd have been able to get everyone + 20lbs baggage into all of the marks, but with differing fuel loads to remain within max weight. The best was the 172P, with 32US gallons, and the worst was the 172 R with only 14 US gallons
I reckon you'd have to try pretty had to load the aircraft beyond its max rearward CofG position, but its very easy to load it beyond MAUW
NB Reims made at least 3 marks of 172 (M, N, & P are the ones I know about), all with different MAUW.
Just for comparison, I also did the calcs for a 182 RG, where you'd have got everybody in, with full fuel, and 20lbs of bags
Brooklands
Anyway since I've done it you're going to get it I initially thought KCDW might have been looking at the aft CG limit for the Utility category, rather than the normal category, but these are a bit further back (~41")
The CG envelope on the marks of 172 I looked at seem to be pretty similar, albeit with different maximum AUWs. Forward CG limit is 35" upto about 1950lbs, then a straight line to either 38.5 or 39.5 (depending on mark letter) at MAUW, with the max reaward at 47.3"
According to my calculations you'd have been able to get everyone + 20lbs baggage into all of the marks, but with differing fuel loads to remain within max weight. The best was the 172P, with 32US gallons, and the worst was the 172 R with only 14 US gallons
I reckon you'd have to try pretty had to load the aircraft beyond its max rearward CofG position, but its very easy to load it beyond MAUW
NB Reims made at least 3 marks of 172 (M, N, & P are the ones I know about), all with different MAUW.
Just for comparison, I also did the calcs for a 182 RG, where you'd have got everybody in, with full fuel, and 20lbs of bags
Brooklands
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KCDW, I have a PA28 Arrow 4, T tail with larger fuel tanks - 72 USG useable. Yes, you can take this with 4 "average" adults, but NOT with full fuel load.
The key to all of this is whatever you fly, it is 101% certain that the aircraft is capable of being overloaded. Do the sums before you fly, especially if it is an aircarft that you are not used to. Once familiar on type you will be able to judge what is overloaded or not quite easily. If field is in any way short, or you have "pucker" factors (wet grass, obstacles etc) do the calculations again.
My steed goes up like a homesick angel with one on board and tabs fuel. try it with 4 adults, full fuel you are probably already over MTOW - add some bags, liferaft etc then those trees at the far end start to look a little uncomfortable.
For jollying aroud local area mine works quite well off of a long tarmac runway with tabs (USG 50 fuel and 4 on board. For continental touring I take no more than 3 adults, tabs fuel and small amount of baggage.
No easy solution, think about the sort of flying you will be doing, the fields you will be using and then research performance charts.
The Arrow is a good compromise though. I am pleased with it.
a2
The key to all of this is whatever you fly, it is 101% certain that the aircraft is capable of being overloaded. Do the sums before you fly, especially if it is an aircarft that you are not used to. Once familiar on type you will be able to judge what is overloaded or not quite easily. If field is in any way short, or you have "pucker" factors (wet grass, obstacles etc) do the calculations again.
My steed goes up like a homesick angel with one on board and tabs fuel. try it with 4 adults, full fuel you are probably already over MTOW - add some bags, liferaft etc then those trees at the far end start to look a little uncomfortable.
For jollying aroud local area mine works quite well off of a long tarmac runway with tabs (USG 50 fuel and 4 on board. For continental touring I take no more than 3 adults, tabs fuel and small amount of baggage.
No easy solution, think about the sort of flying you will be doing, the fields you will be using and then research performance charts.
The Arrow is a good compromise though. I am pleased with it.
a2
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Just for information. Try the same calculations for the C172Q. Longer range tanks and 180 HP (0-360-A4N) engine apparently makes a tremendous difference to both range and performance although only about 5 kts IAS in the cruise. Prob40 the best C172 in the family.
Last edited by Alan O'Brien; 15th Oct 2003 at 22:22.
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I'm surprised it's only been said once on this thread but the solution to the problem is a Jodel D140 or a 160hp+ Robin DR400.
First time I flew a 172 frightened me as, for 4-seaters, I'd only flown the big Jodel. I thought there was something wrong with the engine.
If you want a Cessna then the 177RG was the first metal one which performed well.
First time I flew a 172 frightened me as, for 4-seaters, I'd only flown the big Jodel. I thought there was something wrong with the engine.
If you want a Cessna then the 177RG was the first metal one which performed well.
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Further to earlier posts, attached is an early draft of the Weight & Balance Sheet I've done for the C182 I'm getting checked out on.
It's going to be a bit of an ongoing project - essentially, for the time being, enter actual weight data in cells B53-B59 and it will plot the resultant point on the chart for you, permitting you to see if it falls within the limits. If you go overweight, the total weight cell at B60 will go red. I've been scratting around trying to find an easy way to do the same for the moment cell if you go outside the limits, but that's a bit more complex! I think I'll have to resort to some Visual Basic for that!
Usual caveat applies - this is based on aircraft specific POH / weight and moment info, so requires tailoring for your specific situation.
It's going to be a bit of an ongoing project - essentially, for the time being, enter actual weight data in cells B53-B59 and it will plot the resultant point on the chart for you, permitting you to see if it falls within the limits. If you go overweight, the total weight cell at B60 will go red. I've been scratting around trying to find an easy way to do the same for the moment cell if you go outside the limits, but that's a bit more complex! I think I'll have to resort to some Visual Basic for that!
Usual caveat applies - this is based on aircraft specific POH / weight and moment info, so requires tailoring for your specific situation.
