CG Concerns

[Ed353]

First off, at 250 pounds I have never been called petite!

Recently while considering a Cirrus SR20 I discovered that the plane has a rather narrow CG envelope that made it difficult for a big guy like me to fly with anything heavier than a hamster in the co-pilot seat (perhaps not that bad, but you get my point). Anyways, as I have also considered building a 10 I am wondering if anyone has experienced any issues with the CG, especially among us big guys.

Thank you!

[BobTurner]

As an EAB there will be some variation in the empty weights and CG?s between different-10?s. But in most 10?s everything you load into the cabin - front seats, back seats, baggage - moves the cg aft. Flying solo or both front seats is seldom a cg problem, except for lighter pilots with short legs, in which case the cg may be a bit too forward, a problem easily remedied with a little ballast in the baggage area. Near gross weight, the aft limit may be exceeded in some cases, but less often with heavy people up front. In other words, you should be fine. One hint: if the takeoff cg is near a limit - either fore or aft - you must check the landing and/or zero fuel cg, as it tends to move toward or past the limit as you burn gas.
BTW, in a comparison of the -10 vs SR20, the -10 wins every time. The 10 has more power while weighing less, about 100 lbs higher useful load, faster cruise on the same fuel flow (and even faster if you want to burn gas), climbs much faster, etc.

[rleffler]

I?m about the same weight as you. I?ve never had an issue with two 250lb males is the front.

What you do need to be cautious about is the rear seat. I find that if I get two 200+ folks in the rear seat, you are getting close to gross weight limits especially if you have full fuel. The issue is cg. Take a look at the w&b at what you predict the landing weight to be. You?ll find that cg changes significantly if you burn down to minimum fuel levels.

My recommendation is to always run the w&b for take off and landings. Since you are asking the questions now, which is good, I would also suggest getting a hold of a w&b spreadsheet and do some what if calculations to put your mind at ease.

Also note, the rv-10s vary greatly in empty weight by how they are built. Primer can add weight, especially if it?s applied to heavily, Many primers are supposed to be transparent, not a solid color. Then you have all the various customizations that also add weight. I can tell that mine is about 100lbs over a traditional plans built version that isn?t primed.

The other issue if you are rear cg limits and the front seat passenger gets out first. As soon as the lower themselves on the step, there is a risk of the rudder hitting the tarmac. The solution is for the folks in the back to get out first. Fortunately in the RV-10, there is plenty of room to accommodate that.

[9GT]

My W&B for my old RV-10. You can play around with the numbers but like already mentioned, every RV-10 will be a little different when it comes to W&B due due builder differences.

N959RV Weight & Balance Data
Empty Weight: 1703 lbs. (8 qts oil & Wheel Fairings @ #3.75 lbs. each
Gross Weight: 2700 lbs.
Datum: 99.44" forward of wing leading edge
CG Range Limits: 107.84" - 116.24" aft of Datum
Fuel: 108.90" Aft of Datum
Pilot/Front Passenger: 114.58" Aft of Datum
Rear Seat Passengers: 151.26" Aft of Datum
Baggage: 173.50" Aft of Datum
Right Wheel: 688 lbs., arm 123.85", moment 85209
Left Wheel: 685 lbs., arm 124.15", moment 85043
Nose Wheel: 330 lbs., arm 49.90", moment 16467
Total Weight: 1703 lbs., moment 186719
Empty CG: 109.64" (moment divided by weight)

To Compute Loaded CG
Multiply weight by arm = moment
Add all weights
Add all moments
Divide total moment by total weight

[Ed353]

Thank you Bob! Solid points and I appreciate the feedback.

Ed

[Ed353]

Thanks Bob. I never considered the risk of heavy folks in the backseat causing the plane to lay back, but I can see how that could happen.

Thanks again,
Ed

[Ed353]

Hey David,

Thanks for sharing the WB info. That is very helpful!

Take care,
Ed

[Auburntsts]

Although flying solo stays within CG I nevertheless like to fly with 40-50lbs of ballast in the baggage compartment. My 10 lands better with some weight back there when I'm by myself. YMMV....

EDIT: I'm 5"11" and 185 so factor that in to my response.

[sblack]

You could cut out carbs and walk daily. You will live longer, have a medical certificate longer and feel better, your airplane will perform better. You don't have to be 250 lbs unless you are a professional body builder or power lifter or Navy Seal. It is really simple, really hard, but really simple. Not what you wanted to hear, and I hope it doesn't offend you. If it does I apologize, but it does address the potential for a CG issue.

[BobTurner]

Originally Posted by Ed353

Thanks Bob. I never considered the risk of heavy folks in the backseat causing the plane to lay back, but I can see how that could happen.

Thanks again,
Ed

Just to be clear, this can happen with two people in the back seat, and two other people on the step behind the wing. Not hard to avoid, just be aware.