This is a test that is totally worth doing, most planes fly with a forward CG, and you need to compensate with power and elevator on approaches or during turns, need to add power and trim all the way back to avoid running out of elevator at slow speeds, this will make your plane fly beautiful, I am not an instructor. so do it at your own risk.

Thank you for the video and explanation! I'm currently battling fwd CG in my 182D and am curious how you mounted the 17lbs of lead in the aft tail-cone.

Removed the tail cone and attached scuba weights with heavy duty velcro and heavy duty tie raps to the bulkhead area.
It worked really well, they even survived an emergency landing without moving an inch.

I keep about 40 pounds of camping/survival stuff in my extended baggage. A lot more handy than lead if you need it.

I would suggest to take videos like this with a grain of salt.

Yes, in principle, this is correct; an aircraft does need to have a proper CG in order to fly correctly.

That said, If one has to permanently mount 17 lbs aft of the tail cone in a 182, or mount a 25 pound battery 3 feet further aft in a place where it never was designed to be, suggests something is SERIOUSLY wrong with how the aircraft was modified/set up.

I see threads from time to time where folks “claim” that mounting ballast is ok, but no one has ever presented the documentation other than the FAA general publication discussions. I’d love to see the engineering.

Moreover, and looking past the “how” conundrum… even IF one had a slip of paper with a signature giving permission to do something like this, no one knows the unintended consequence of stressing a body with such an arm in a non-standard environment (a la hard Backcountry use) in a 70 year old airframe without some pretty interesting data behind the modification.

In other words, “seems to work fine” might only be good until it’s not.

Gutting and modifying these birds is not without trade offs, as evidenced by this video… and more often than not, it’s only the mutual admiration society that cheers, whilst the old sage grey beards quietly sit back and shake their heads.

Doing things just because the “STOL“ guys are doing them in competitions might not necessarily be best practice.

What I’ve learned after dabbling here and there is that nothing is free… unless I can really understand the price of admission, I’m now less inclined to buy the ticket.

In the simplest form, the general principle, as stated is correct… We want the aircraft to be balanced properly, so that it flies correctly. What is being overlooked, is the “need“ to do this kind extreme action.

Advocating taking the green pill to counteract the effects of the yellow pill is missing the forest for the trees. The question needs to be asked if the green pill should be taken at all…

In watching the video I was reminded what Tyrell said to Roy: “The light that burns twice as bright burns half as long - and you have burned so very, very brightly.”

Anyway… just my AM .02

Greg-

There is more to weight and balance than simply balancing a teeter totter. Moment is calculated by multiplying arm times weight. Calculation of moment of inertia is arm SQUARED.

A small weight with a long arm significantly alters the moment of inertia. Control forces may not be sufficient to recover from a spin.

The main reason you see Pa 18s with weight tied to the tail at STOL competitions is to help keep the tail down when braking hard after landing not for CG. Aircraft with a moveable stabilizer can be trimmed to provide the downforce needed for the type of approach they are talking about. As noted roper placement of cargo prevents the need for excessive Ballast (useless weight). The 170 and some other aircraft have a fixed stabilizer so attention to loading important. A power on approach also helps keep the tail down.
DENNY

qmdv wrote:I keep about 40 pounds of camping/survival stuff in my extended baggage. A lot more handy than lead if you need it.

Yup

Plus the idea of 40lbs of lead on a non load bearing surface

I understand the principles here and why you're doing it. It can improving the pilot's flying experience, if you are planning on beating up gravel bars or strips for fun.

Practically, it seems to me it's not quite as compatible with many kinds of 'real world' backcountry flying. Such as situations where you are going in and out, with a mission in mind, with different or changing loads on board (hunting, moving gear, long distance trips when you start heavy and use a lot of fuel, etc). In many cases, you need all the forward CG you can get, when you're first firing up the engine at the start of the day.

Moving ballast or burning fuel to manage CG is something a ship or airliner does, and it totally makes sense. For a light single engine backcountry machine, I agree there benefits on offer, but practically it isn't hard to become skilled at flying with whatever CG you have to work with, provided it's within your normal operating envelope. I don't see any concrete need for this kind of testing and operating regime. Each to their own.

NineThreeKilo wrote:

qmdv wrote:I keep about 40 pounds of camping/survival stuff in my extended baggage. A lot more handy than lead if you need it.

Yup

Plus the idea of 40lbs of lead on a non load bearing surface

Is an extended baggage really any kind of better load bearing surface than the tail bulkhead?

Also it doesn’t take 40 pounds if it’s way back in the tail.

Is an extended baggage really any kind of better load bearing surface than the tail bulkhead?

Well yes, it’s STCd to do just that. 50 lbs in my case.

I was worried that I would dislike my forward CG when I did my 180 conversion but it’s not a problem. Does it fly differently with different CGs? Well yes but that is what the pilot is for.

An extended baggage area is a very functional upgrade; offers good operational value for the dollar, is fully engineered and approved via an STC.

motoadve wrote:....attached scuba weights with heavy duty velcro and heavy duty tie raps to the bulkhead area......

Velcro & tiewraps? Wow.
Don't think I'd want to add ballast, at least in this situation,
but I'd at least bolt it into place.

I seem to have solved all my ballast problems by having grown kids and a dog.

qmdv wrote:I keep about 40 pounds of camping/survival stuff in my extended baggage. A lot more handy than lead if you need it.

I'm with you. A gallon of water and survival gear can come in pretty handy.

motoadve wrote:need to add power and trim all the way back to avoid running out of elevator at slow speeds

Interesting post which left me somewhat puzzled.

We built my 170 pretty much like your’s appears to be set up.
O-360 A1A and MT 2-blade up front, Sportsmann, VGs, extended baggage, bigger tires.
No back seats in mine, and the battery is on the firewall.

We've flown her a couple of times without any CG-induced "problems".
There’s no excessive back trim necessary and elevator control is maintained throughout a slow approach and short landing.

Why the differences in handling, what other factors could contribute?

Of course it flies fine without ballast, but with a proper balanced CG flies much much better, no comparison.
When I test flew the 170 before buying it felt very nose heavy, no ballast whatsoever , flew nice but for slow speed landings it will drop like a rock as soon as power was reduced, so approach speeds were higher.
I had to add 70 pounds of ballast in the cargo area to get a centered CG.

For normal backcountry flying, a nose heavy airplane works and it can fly like this forever, (not very nice though) for STOL competitions or Off airport operations into tight places , it would be a handful flying it nose heavy, flying the 170B light and with a proper CG makes it perform really nice for my kind of flying, it can do 40mph approaches (groundspeed, no wind IAS showing 30 or so) go try that with a nose heavy plane, no way you get that performance unless the nose is pointing to the moon.

A properly balanced 170B flies amazingly nice, my 170 the way it is now , which does not need ballast anymore, my CG is just in the center not aft, you DO NOT want aft CG, that is when it becomes dangerous. Nothing wrong with a center CG which makes for a nicely balanced plane. Moving the battery aft allowed me to get rid of 70 pounds of ballast, battery weight 21 pounds, not 40 like someone says.

This works for me and my plane, not trying to convince anyone of anything, but if you go to any Backcountry flying advanced course, proper CG its a very important subject.

Basically airspeed is controlled by the yoke/stick. Which in turn control the attitude (nose up/down) of the aircraft. A Cessna 170 that can slow down to 40 mph and maintain altitude is going to be nose high!!! Even a super cub at 40 mph is nose high I don't care what the CG is. Show us a video of the plane flying level over the ground at 40 mph.
DENNY

daedaluscan wrote:

Is an extended baggage really any kind of better load bearing surface than the tail bulkhead?

Well yes, it’s STCd to do just that. 50 lbs in my case.

I was worried that I would dislike my forward CG when I did my 180 conversion but it’s not a problem. Does it fly differently with different CGs? Well yes but that is what the pilot is for.

I have an extended baggage kit in my 175, I needed something to correct CG to make it possible for me to fly since I tend to make planes extra nose heavy as soon as I sit in a front seat. The engineering of the ext baggage kit looks pretty underwhelming… it’s hard to see it as more structurally sound than the tailcone bulkhead, and I’m asking the ext baggage to carry at least 3x the weight that would have been needed if placed farther back. I’m getting by with the ext baggage and ballast, but some days I wish I would have put more effort into finding someone willing to bolt a few pounds way back in the tail and sign it off as a minor alteration.

BigBen wrote:

daedaluscan wrote:

Is an extended baggage really any kind of better load bearing surface than the tail bulkhead?

Well yes, it’s STCd to do just that. 50 lbs in my case.

I was worried that I would dislike my forward CG when I did my 180 conversion but it’s not a problem. Does it fly differently with different CGs? Well yes but that is what the pilot is for.

I have an extended baggage kit in my 175, I needed something to correct CG to make it possible for me to fly since I tend to make planes extra nose heavy as soon as I sit in a front seat. The engineering of the ext baggage kit looks pretty underwhelming… it’s hard to see it as more structurally sound than the tailcone bulkhead, and I’m asking the ext baggage to carry at least 3x the weight that would have been needed if placed farther back. I’m getting by with the ext baggage and ballast, but some days I wish I would have put more effort into finding someone willing to bolt a few pounds way back in the tail and sign it off as a minor alteration.

This discussion appears to be a very polarizing one, pros and cons on both sides of the conversation which is always healthy in my opinion. I can accept either method but only if it's supported by proper engineering. I highly doubt much engineering flight testing was done for either "fix" so some credit to Motodave for his efforts. However for me the lack for formal documentation and engineering hinders the aft bulkhead position, velcro & tie wraps just don't cut it for me. The extended baggage is supported by documentation, installed with proper aviation fasteners and in addition is a functional option too be used as required for the mission of the day.