Getting those four adults into a C172...

[KCDW]

Probably start off a flame war here, but I would appreciate people's views.

On occasion, I would love to take 4 adults up. All I have easily at my disposal are normal 4 seat trainers (160 HP Warriors or C172s).

Received wisdom says don't do it.

The alternative is problematic. Travel to a field 1 hr away, and rent an Arrow at c£150 per hour (that's after x hours complex conversion training).

Yet, at my airfield, you often see 4 well built adults (including an instructor) getting into a 172 and taking off on a pleasure flight. When asked how they do it, the reply goes something like: "sure you can take 4 adults up... but you better check the weight and balance.

So the other day, I got the documentation out on the best Warrior and C172 where I fly, and did some calcs.

The C172 has the advantage, in that it is much lighter, but has about the same load bearing as the Warrior. My heart rose when I figured out that, in terms of weight, I could take off with 2 * 13 Stone adults in the front, 2 * 11 Stone adults in the back, 28 lbs of baggage, and a half tank of fuel... just.

My heart promptly sank when the C of G was way aft of the limit (38.5" at full weight is the limit, and I had calculated the above load at 44").

So... what to do.

1) Only make friends with very light adults or mature infants.

2) Bite the bullet and convert to the Arrow (could be fun), but that inpromptu trip to L2K would lose a lot of the shine.

3) Figure out how the instructors manage to take off in a heavily loaded 172...

4) Buy the right plane or join a Group in something decent. This option is not for me at the moment - can do without the strings.

5) Your option here... :)

[FlyingForFun]

I've only flown 4-up in a basic trainer once - it was a PA28, and one of the four was my 12-year-old (and small for her age) cousin. Fuelled to the tabs, which came in at just under the max allowable weight. I don't recall any CofG problems, so if that's a problem with your C172 then it may be worth checking out the PA28. I do remember that it used a hell of a lot of runway!!!

FFF
--------------

[gingernut]

KCDW, I have simillar problems with C172.

As the aircraft is run by the club, and slot times are a premium, (and I havn't worked out how to empty the fuel), I have to assume that the tanks are full prior to departure.

If I am taking myself (16st), fat knacker brother (18.5st), and flight bag (10lb), and assume full tanks, then I have 6lb to spare on take off !

Incidentally, the aircraft handles well, but I notice that I need lower nose attitude on initial climb out.

[Aim Far]

I've had 4 up in a PA28 with tabs fuel (about 4 hours) and the two in the back were large marines and we did weight and balance checks which were just OK for both max weight and CofG. Might have been a 180 though.

I have also read on proon that the Arrow can't take 4 up with max fuel anyway though I've never tried that myself so can't comment.

[Evo]

People who love sausage and airplanes shouldn't try to make one look like the other, as did the operator of a 172B in September in Florida. During the turn to crosswind, the airplane descended into the trees.

The pilot reported that the airplane's fuel tanks were filled to capacity just before the flight. Aboard were the pilot, who weighed about 250 pounds, the right front passenger at 300 pounds and the positively svelte rear seat passenger, a mere 200 pounds. A 50-pound bag of sand was found in the rear of the baggage compartment.


From http://www.avweb.com/news/airman/184311-1.html :)

[KCDW]

Interesting comments so far - but no solutions!

Evo - very funny :E :E :E , but I'm not talking extremes here.

Aim far - Had to be a 180 HP unit, the 160 just didn't cut it in my calculations.

gingernut - ... but at least you didn't have that critical 50lbs of sand in the back :) . Anyway, with no one benind you and your brother, the C of G would probably have been fine.

Its the two in the back and the baggage which kills the deal....

Keep them coming...

[Aerobatic Flyer]

Solution? Find a 160hp Robin DR400, which will take 4 normal sized adults and plenty of fuel, and still be within weight and C or G limits.

I was once lured by the prospect of a free flight into flying an overloaded Warrior. We had two aircraft mechanics in the back, an instructor (who should have known better) in the right seat, and me (who also should have known better.... :O ) flying. Add to that nearly full fuel, and we were way over weight -

The instructor said it was fine, and I naively believed him. We needed 900m to take off, then climbed at maybe 200fpm. It was a slightly frightening experience, which I don't recommend trying for yourself!

[18greens]

I am surprised you ended up with a CofG issue, the usual issue is simply with 900ish lbs of useable weight 4 * 200lb people and fuel is hard to fit in. With that load distribution it should be in CofG limits. Check another plane's W&B if it is an issue.


There are people who seem to fly over MAUW regularly. Look at any 152 with 2 people and full tanks. If you do that you need to accept the consequence if there is an accident, ie no insurance and coffee with no biscuits at the CAA after the accident.

The arrow is a nice plane for 4 up and a good plane to graduate onto. You could do worse.

[MasterCaution]

The C172 has the advantage, in that it is much lighter, but has about the same load bearing as the Warrior. My heart rose when I figured out that, in terms of weight, I could take off with 2 * 13 Stone adults in the front, 2 * 11 Stone adults in the back, 28 lbs of baggage, and a half tank of fuel... just.

My heart promptly sank when the C of G was way aft of the limit (38.5" at full weight is the limit, and I had calculated the above load at 44").

Further to 18greens' comment. Are you sure about the aft limit? I'm assuming your comment is for the 172. The one I fly (a 172SP) has an aft limit around 47" (IIRC). Obviously it depends upon the datum used. The same loading you suggest puts me slightly overweight but the CG is well within limits (obviously with a different basic weight and CG to your aircraft but CG is unlikely to be vastly different). This is for the normal category, utility is going to be somewhat more limited.

MC.

[mad_jock]

Most instructors have done the, just filled up and 3 fat punters turn up for a trial flight.

Which is what you have seen at the club.

Is it illegal yes.

Is it done every weekend somewhere in the UK yes.

Would I advise it no as an Instructor you tend to get bitten but because you are very current you get away with it. Once was enough for me.

If you do do it, stick 10knts on your Vr and go for a cruise climb not Vy

By the time you have flown for 1 hr the fuel burn the weight should be back to max for landing.

I have seen photo planes with full long range tanks fitted 2 people on board and 50kgs of gear. It took the whole of the runway to get off the gound which we normally would only take an 8th.

I would go for the arrow whats an extra 300 quid when your playing with peoples lifes.

MJ

[Circuit Basher]

(as usual, I'm firing off at a tangent, but here we go anyway :))
Due to my flying slot in a C182 being cancelled yesterday (due low cloud at Perth), I spent some time on groundschool for wobbly props with an instructor and then spent some time copying info from the POH and the Aircraft Weighing Certificate so that I could make my own spreadsheet for calculating W&B.

I somehow managed not to write down what the arm was for the Rear Pax (front seat crew was 37" for comparison purposes). I made an estimate just to test the spreadsheet and with pretty well any combination of flying configurations, I always get the CofG sitting too far forward. This is a spreadsheet which has worked find for the Fuji and I have tweaked it for the 182.

I will be at the club on Friday for another attempt (so will double check all the relevant data then), but if anyone can give me an indication of the Rear Seat Arm in inches, I would be most grateful, as it will allow me to test the spreadsheet before I use it.

[KCDW]

Again, thanks for the comments - some very good food for thought.

I'll recheck the C172 docs. They were very grubby to be fair, and I may have got the wrong stats. Its a Reims F C172 BTW.

As it happens there is a Robin DR400 for hire at my field, and I'm told it has marginally better load bearing that the C172 - anyone able to verify this (say use the load example above)?

I guess Mad Jocks comments are very pertinent. I don't want to do it illegally. But if I can get within the target loading above, then, I will be happy.

The Arrow is still a possibility, it would be good to have the extra power, and an alternative route for going 4 up. As a slight side thread, those of you who have done complex conversion for similar reasons - was it worth it, do you use it regularly?

Thks

[down&out]

I was lucky to learn on a wobbly prop & injected engine, so only had to "step up" to retractable u/c to get in an Arrow a number of years ago.

"Is it worth it?" - well, that depends on what type of flying you want to do in the long term. Me- I enjoy filling the a/c with friends, luggage and fuel and going abroad for weekends/ hols - so definitely yes. I now really only tend to fly Cherokee Sixs, Saratogas & Arrows.

However many people seem happy bumbling round the local area, occasionally taking one or two people up.

So what type of flying will you be doing in the longer run? If it’s the first then check out the w&b on those a/c available to hire near you & do the conversion. If it’s the second, then why not split your friends & take them up in two trips?

PS - Do call up the owner of the Arrow you are referring to. Depending on the version, you may be surprised how poor its useful load is - an Archer can often be better.

[KCDW]

The Arrow is a 201. I thought 200 horses woud be plenty, but your comment vis the Archer made me think. Just did a quick trawl on the web and came up with these 2 pages which give a lot of food for thought (apart from the US hire rates that is:( ).

http://www.plusone.org/fleetover.html

http://www.ecas.com/resources/weight.html

In summary, the increase in usable load is really very marginal, by the time you fill up the tanks or go to tabs. Stick 4 tubbies, and a full tank in any one of these planes, and you're not getting off the ground legally!

[mad_jock]

I think you are beginning to understand why most people take the risk and fly heavy.

And I have seen quite a few examiners fib about their weights on ppl tests just so the could go with full tanks. And I am talking 70-80kg fibs.

MJ

[drauk]

Circuit Basher, my 182Q POH shows a front seat lever arm of 32.5 to 57 inches (and it would certainly be nearer 32 than 57 - I have a friend who is 6'7" and even he was only about half way back) and a rear set arm of 74".

[Mike Cross]

CB

My copy of ProPlan shows rear seat arm to be 74.02 in max wt 441 lb

The others are

Front 37.01 max 441 lb
Fuel 47.9 max 450 lb
Baggage A 96.85 max 119 lb
Baggage B 114.96 max 79 lb

Empty 1742lb at 37 in

mauw 2950 lb between 39.49 and 48.5

Not of course authoritative but may be useful.

Mike

[RatherBeFlying]

Just looked at a C172N ground school manual.

With an empty weight of 1460# -- Check the sheet.

and full standard tanks and NO baggage

you and your passengers can weigh 600# with clothing.

With long range tanks, everybody has to go on a diet and get rid of 60#

I fell into that trap many years ago and flew once or twice with four seats filled and long range tanks and was maybe 100# overweight on takeoff.

V speed correction factor is 2% and of course climb and runway performance decreases.

[javelin]

Folks, wait until you start hauling skydivers !

We used to carry 3 parachutists with their kit, plus me, plus fuel in a 172 - don't ask !

Then you go up to a 182 - now we are carrying 4 parachutists, plus me, plus fuel.

Now we digress and go down the 206/7 route. We have 5 in a 206 and 6 in a207, all climbing out around the door - 3 in, 3 out on the 207 - remember that Werski !

Or, you could go down the Lance or Cherokee 6 route - Mmmm 6 plus me in a Lance - book said it was OK, up at 10,000, 1 out, 5 in - we had some care for the c of g.

Oh, happy days !!

Now they get frit about an extra tart on an A320 :ok:

[Gertrude the Wombat]

Instructor (seeing if I can remember how to do a W&B for a C152): "Right Tim, you weigh 180lbs, don't you."

Me (innocently): "Haven't a clue."

I reach for the scales.

Instructor: "Don't you dare step on those scales!!"

[PPRuNe Towers]

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:mad: :mad:

Thankfully impossible with my size and wearing that insulated Sheila Cooper suit :E :E :E

Rob

[Alan O'Brien]

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.

[Circuit Basher]

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"! :)

[KCDW]

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 :uhoh: 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:ok: :ok: .

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...

[Brooklands]

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 :p

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 :ouch:

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 :ok:

Brooklands

[arrow2]

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

[Alan O'Brien]

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.

[Miserlou]

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.

[Circuit Basher]

Further to earlier posts, attached (http://uk.msnusers.com/CircuitBasher/Documents/Cessna%20182%20Wt%20and%20Bal%2Exls) 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.