Weight in rear of Piper Warrior.

[saracelica]

Talking to a student (that hasn't solo'd yet) she and the CFI took her husband to give him the view from 2500ft. I commented "How'd you like the takeoff with that weight in the backseat?" She said "I didn't notice a difference". Really! Last night I took her and the same CFI (as safety pilot) to get night current - been 2 years since I flew at night and I could tell the tail was heavy and she was only 125 and her husband is MUCH more. Is it me and just psychologically I knew it'd be different with her or was she not paying attention on the takeoff roll (possible the CFI *helped* on the takeoff since she hasn't solo'd but still!)

If she can't feel that difference she's going to be in for a surprise when she does solo when the CFI gets out.

Thoughts.

 

[steingar]

If the airplane is within it's envelope it shouldn't be that big a difference. I didn't notice a huge difference in my bird when I filled the seats (with small people, of course). Just the usual stuff of heavy vs. light airplane. But Warriors are a bit longer than my puddle jumper, so perhaps it's different.

 

[Bob Noel]

When doing my primary training <mumble> years ago in the 172, my instructor would occasionally bring a friend or two along as extra weight in the back. This taught me not to get too used to a particular weight configuration - part of her plan to make sure I wouldn't get screwed up without her (light) weight in the right seat when I solo'd.

I notice the weight in the back, but it is well within the capabilities of the aircraft.

Much more significant is how a lightly loaded warrior flies in the cold of winter vs a warrior with full fuel in the summer.

 

[poadeleted20]

The change in pitch feel with an extra 175 pounds or so in the back seat is there, but it's subtle. A pre-solo Student Pilot might not have developed a sufficient sense of the "normal" pitch response to notice the difference with the extra weight in the back.

 

[Z06_Mir]

I never flew with anyone in the back of the Warrior. I do however notice a change when I'm loaded up in the 182. Probably the biggest change is the slightly more aft CG vs the very much forward CG with just 2 on board.

 

[Mattl]

The change in pitch feel with an extra 175 pounds or so in the back seat is there, but it's subtle. A pre-solo Student Pilot might not have developed a sufficient sense of the "normal" pitch response to notice the difference with the extra weight in the back.

My experience has this statement right on the money- I've flown a PA28-161 on all the corners of the normal envelope and the performance between light and heavy is very noticeable. The forward and aft CG differences on the other hand are noticeable, but docile. Guessing here- I'd say lack of experience is the root of the lack of noticed change.

 

[MAKG1]

In a Warrior, I don't feel much difference on takeoff with an inch or two more aft CG, but the trim wants to be in a different place. Once that's corrected, the main effect is that the aircraft flies a little more stable, and a little faster, with a little less pitch. It's not a big effect, as long as you aren't close to the limits.

It's kinda hard to hit CG limits -- fore or aft -- with passengers (but of course it should be checked anyway). A lot of luggage can do it. But mostly, W&B in a Warrior is keeping under max gross.

What this means is that the student pilot is trimming for conditions. Good. It would be a bigger effect if it was trimmed by habit.

 

[Sac Arrow]

My Turbo Arrow was very nose heavy, and it was just plain hard to land properly with the front seats only loaded. Add a couple pax to the rear and it was much easier to flare. Not an issue with the Hershey bar Arrow or the 140 I used to fly.

I prefer to fly loaded close to the aft CG limits for a couple reasons, that being one of them. The other is that there is less drag in flight, so more speed and economy.

 

[poadeleted20]

In a Warrior, I don't feel much difference on takeoff with an inch or two more aft CG, but the trim wants to be in a different place. Once that's corrected, the main effect is that the aircraft flies a little more stable, and a little faster, with a little less pitch. It's not a big effect, as long as you aren't close to the limits.

The airplane is less stable in pitch and less stick force for the same pitch response with the cg further aft -- aerodynamic axiom. If you're not feeling that, you're in the same boat as the OP's Student Pilot friend. I'd be happy to demonstrate with a fish scale and an adult passenger if you'd like.

It's kinda hard to hit CG limits -- fore or aft -- with passengers

My experience suggests otherwise...

...(but of course it should be checked anyway).

...so keep checking. Caveat aviator.

 

[gkainz]

I need to calculate W&B for 3 buffalo in the back seat of our Saratoga for a possible trip next month. I don't think it's going to work ... probably can't make them stay seat-belted for takeoff and landings.

Looks like a trip for the Dodge Ram.

 

[MAKG1]

Ron, maybe you can explain this for me.

Every explanation I've run into about "stability" with aft CG confuses it with control input gain. They are only barely related. Stability means that it holds a setting -- if trimmed carefully, a more stable aircraft will take longer to deviate a given amount, without any control input. A higher input gain means that a given control input will have more effect.

A more stable aircraft will also take longer to damp out a phugoid than a less stable aircraft, with equivalent (generally zero) control inputs. A more stable aircraft will also execute the phugoid faster, as the restoring force from a trim deviation is larger. This ought to be relatively easy to measure even without a fish scale.

And, aside from loading beached whales into your passenger seats, how do you get out of CG in a Warrior in normal category while staying under max gross? I can't get it more than a couple of inches from 88 in either direction, unless I start stacking sandbags in the cargo area.

 

[poadeleted20]

Every explanation I've run into about "stability" with aft CG confuses it with control input gain. They are only barely related. Stability means that it holds a setting -- if trimmed carefully, a more stable aircraft will take longer to deviate a given amount, without any control input. A higher input gain means that a given control input will have more effect.

There are a number of issues here, including the difference between static and dynamic stability.

Static stability is all about how much increase in stick force is required to deviate further as you deviate from the original pitch attitude. You can measure that by using a fish scale to pull the yoke, and see how much additional force is required to get it to go more nose-up as pitch increases. Put an extra 150-200 lb in the back, then try it again, and see how much less force is required for the same angular displacement.

Dynamic stability is how quicky the airplane returns to its original attitude when displaced. You can measure that by using the fish scale to put a certain amount of pitch force on the yoke, then letting go and seeing how long in time and how many oscillations before it settles back to the original attitude. Put that extra 150-200 lb in the back, try it again, and see how much longer and how many more oscillations occur before it settles again.

And may I suggest the excellent See How It Flies web site, or H.H. Hunt's classic text Aerodynamics for Naval Aviators, for more detail?

A more stable aircraft will also take longer to damp out a phugoid than a less stable aircraft, with equivalent (generally zero) control inputs. A more stable aircraft will also execute the phugoid faster, as the restoring force from a trim deviation is larger. This ought to be relatively easy to measure even without a fish scale.

While a phugoid oscillation is related to pitch stability, even a very stable plane get get into a phugoid oscillation.

And, aside from loading beached whales into your passenger seats, how do you get out of CG in a Warrior in normal category while staying under max gross? I can't get it more than a couple of inches from 88 in either direction, unless I start stacking sandbags in the cargo area.

Not all Warriors have that far forward an empty cg. It is indeed possible in many of them, especially with light people up front.

 

[Matthew]

If you want to feel what weight in the baggage are of a Warrior feels like, fly an XC with my CFI. She would take her dog with us once in a while, on long flights. He'd ride in the luggage area and weighed about 80 lbs. W&B was no problem. But, every time, right after we would level off, he'd circle a couple times, then lay down and go to sleep. Having 80 lb in the back moving around in a circle with about a 12" - 18" radius would sure get your attention as the CG moved not only back and forth, but side to side.

 

[John Baker]

In a Warrior, I don't feel much difference on takeoff with an inch or two more aft CG, but the trim wants to be in a different place. Once that's corrected, the main effect is that the aircraft flies a little more stable, and a little faster, with a little less pitch. It's not a big effect, as long as you aren't close to the limits.

It's kinda hard to hit CG limits -- fore or aft -- with passengers (but of course it should be checked anyway). A lot of luggage can do it. But mostly, W&B in a Warrior is keeping under max gross.

What this means is that the student pilot is trimming for conditions. Good. It would be a bigger effect if it was trimmed by habit.

This pretty much sums up my experience with a backseat passenger in my Warrior. I also noticed that it seemed to land a whole lot nicer. Trim has to be set differently as soon as you start your climb away from the airport.

-John

 

[poadeleted20]

If you want to feel what weight in the baggage are of a Warrior feels like, fly an XC with my CFI. She would take her dog with us once in a while, on long flights. He'd ride in the luggage area and weighed about 80 lbs. W&B was no problem. But, every time, right after we would level off, he'd circle a couple times, then lay down and go to sleep. Having 80 lb in the back moving around in a circle with about a 12" - 18" radius would sure get your attention as the CG moved not only back and forth, but side to side.

Could be worse -- you might climb up above 10,000 and then discover something about Boyle's Law and the methane in the gut of an 80-lb dog. BTDT, fortunately in a Grumman with a canopy which can be opened in flight to vent the fumes.

 

[Kevin H.]

I flew Piper Tomahawk's during my training so the only different I really felt when solo'ing was in the turns of course, not so much when climbing or descending. My instructor weighed a little more than I did so I just burned the right tank a little longer to compensate.

As long as the aircraft is within CG limits I wouldn't figure there would feel like much of a difference. My flight school buddy went up with me every now and then in the Seminole and It never really felt much different with him there or not, accept for in the right turn.

 

[Clark1961]

Isn't the back seat passenger in a Warrior essentially sitting on the spar carry-through? Isn't that pretty darn close to the center of lift?

Result: change pitch? yeah, maybe a little bit, prolly more change in gross weight...

 

[NineThreeKilo]

Load a 207 to gross, wee bit different lol

Load the van up aft and you'll tail strike it.

Other planes feel the same at gross on the controlls just more larthagric, pipers, many tandem t/w, Stinsons, tend to fall into this category more so then Cessnas.

 

[bbchien]

It's not you. A student pilot flying with a CFI and a husband in the back....OMG. She has enough trouble listening to the a/c talking to her when she's alone. Now add two stressors and she's positively DEAF to the a/c talking to her with all that going on.....