Cardinal 177RG W&B?

BigBadLou

BigBadLou

Final Approach
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Looking at some basic W&B data for a 177RG, it seems that two occupants in the front with some fuel would easily put the plane fwd of the envelope.
I don't have the exact numbers on me but let's look a simole full-fuel situation for a XC trip.
400lbs front seats + 360lbs fuel put the plane squarely outside of the envelope.
Am I right or am I looking at the wrong W&B data?
 
I believe you're right. When I was looking to buy, I looked at a cardinal and the owner kept a case of about 40 waters in the back of the plane as ballast just to out the cg back.
 
True. Seen it too. Do it with my Cherokee too.
For some reason, the W&B on the Cardinal is simply way too silly by the numbers. I did the math and with full fuel and by myself, I am already fwd of the envelope. Forget a co-pilot. I'd need 40lbs minimum in the aft baggage area to get onto the front edge.
Then the wife hops into the front seat. Maxing out the rear baggage weight limit doesn't put me back into the envelope, lol.
That sounds like a design flaw.

Or much more likely, it sounds like a math flaw. Maybe I got my numbers wrong.

Can any Cardinal owners verify that these are right?
Code: 
Items:		Weight:	Arm:	Mom/1000
Empty AC	1800	102.5	184.5
Pax Front	0	94.0	0.0
Fuel		0	100.0	0.0
Pax Rear	0	134.0	0.0
BaggageA	0	155.0	0.0
BaggageB	0	179.0	0.0

I'll try to attach the Excel spread-sheet with the nice envelope graph.
 
My C172 is the same way. Forward of CG rage with just me and any fuel situation. Keep my step ladder, tools, flight bag, etc in the back all the time and it just works out.

Took my 270 Lb buddy on a short trip. Had to throw scuba weights in the back on that one.
 
BigBadLou said:
Looking at some basic W&B data for a 177RG, it seems that two occupants in the front with some fuel would easily put the plane fwd of the envelope.
I don't have the exact numbers on me but let's look a simole full-fuel situation for a XC trip.
400lbs front seats + 360lbs fuel put the plane squarely outside of the envelope.
Am I right or am I looking at the wrong W&B data?
Click to expand...

Seems to depend on year.

The one I originally transitioned on required 90 lb of ballast in rear cargo with two up front. The one I use now doesn't need any ballast at all.

So yes, it's plausible.
 
gov98 said:
I believe you're right. When I was looking to buy, I looked at a cardinal and the owner kept a case of about 40 waters in the back of the plane as ballast just to out the cg back.
Click to expand...

I owned a fixed gear Cardinal. Kept a gallon jug of water back there and a small suit case with more survival gear than was really necessary for most flights I did just for the weight.
 
Remember, we're never supposed to weigh more than 170#. (I am trying to lose weight but....)
 
The Cardinal does have a pretty far forward CG, and maybe more so with the extended range tanks. You will find living with it that it's not that hard to live with, and actually makes it easier if you want to carry more people. We do regularly carry around some extra weight in the back, such as tie down ropes, a small step ladder, and extra oil. But it's really nice to have that stuff back there when you need it, and easily removed if you don't want. Having the forward CG was really nice when I wanted to fly upfront alone with my wife and infant son/car seat in the back, with baby gear back in the baggage area. I had no issues with the CG being too far aft.
 
Thank you for all the responses, gentlemen.

Funny tidbit: if you have FULL passengers in the back, NO pilots in the front, NO fuel and all allowed baggage in the back, you are STILL within the CG envelope. How silly is that?
That is what leads me to believe that they could have done a better job with the wing position.
 
BigBadLou said:
...That is what leads me to believe that they could have done a better job with the wing position.
Click to expand...

Here's what they did with the C187 prototype. With a bigger engine, it was even more nose-heavy. Looks like they moved the whole wing forward a few inches.

attachment.php
 
That is cool, thanks for posting. Too bad they didn't produce that as the 1980+ version of the Cardinal......

Kevin
 
N53KL said:
Not to pick nits but that is a 172 with a bigger engine, not a Cardinal :)
Click to expand...

Its more like a 175 with a bigger engine.

I flew a 172XP several flights and really didn't like it over the cardinal.

Pretty sure the main reason it won over production is because the Cardinal was an expensive airplane to build compared to the 172XP.

Many 177s and 172XPs are around the price of a 182, which is a bigger step up from the 172 world.
 
Last edited:
N53KL said:
Not to pick nits but that is a 172 with a bigger engine, not a Cardinal :)
Click to expand...

It has wing struts, but it's not a 172, despite the number. Neither is a 172RG; there are lots of differences. The real obvious one is the constant speed prop.
 
MAKG1 said:
One of the design points of the Cardinal was to improve visibility. That pushes the wing back.
Click to expand...

So they "fixed" one problem by creating another one. Typical engineers. :D
(hey, I can say it, I am one of 'em! And ... um ... kinda .... proud of it)

I have actually wondered about this whole weird W&B problem for a while. My Cherokee has a similar problem, though not as pronounced.
Instead of having to put 100lbs in the baggage area, it would be (mathematically and geometrically) smarter to put a temporary 10lb weight on the tail hook. It provides the exact same benefit with minimum decrease in useful load (compared to 100lbs). And if done right, it can be installed or removed in a matter of seconds. What am I missing here?
 
BigBadLou said:
That is what leads me to believe that they could have done a better job with the wing position.
Click to expand...

MAKG1 said:
One of the design points of the Cardinal was to improve visibility. That pushes the wing back.
Click to expand...
That, and the need to move the main spar carry-through (where the wing is thickest) behind the heads of the front-seat occupants. That's also why they used a "laminar-flow" airfoil (64A215, transitioning to 64A412 at the tip), rather than the tried-and-true NACA 2012 -- the laminar airfoil's maximum thickness is further aft.

Said Cessna aerodynamicist and test pilot Bill Thompson:
"This [wing placement], of course, produced a nose-heavy condition, further aggravating the large pitch-down forces caused by the long-span wing flaps. To obtain the tremendous elevator power needed for a tail-low touchdown at a forward center of gravity position of only 5% of mean aerodynamic chord (MAC), we were forced to use an all-movable (stabilator) horizontal tail. For comparison, the C-172 forward C.G. limit was a more typical 15.5% MAC."​

Compare a '66 C-210F (strutted) with the next year's strutless C-210G. You'll see that the wing was shoved further back there too, and that in turn required a 6-sq-ft increase in horizontal tail area.

That's one of the penalties of a strutless high-wing airplane. Low-wing designers, of course, have the luxury of hiding the spar carry-through under seats.
 
BigBadLou said:
Instead of having to put 100lbs in the baggage area, it would be (mathematically and geometrically) smarter to put a temporary 10lb weight on the tail hook.
Click to expand...

You have a tail hook on your Cherokee?

I gotta see this.

Where do you connect the catapult? :D

Anything you put outside the airplane is going to make drag. And anything "temporary" might be more temporary than you intended (and, FYI, that's why I don't recommend water for ballast -- a leak can be bad news; I typically used 15 lb sandbags, tied down).
 
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