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CG Concerns

Ed353

I'm New Here
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!
 
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.
 
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.
 
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
 
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
 
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.
 
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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.
 
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.
 
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.

Carbs are not bad, I don't know why this advice get repeated over and over. Walking, while great for lots of health/mental reasons also will have minimum impact on weight loss. Even the "magical 10K steps a day" burns about 500 calories so not a huge impact as a lot of people then eat more.

It's simple math- eat fewer calories than you burn- carbs, fats, proteins, etc. Just eat a healthy diet with lots of veggies, fruits, lean proteins and grains (carbs!).
 
Threat of a thread derailment :eek: but... calories consumed and burned is indeed the calculus for weight maintenance/loss, but table sugar is a special kind of bad independent of its caloric content. It's in how the liver responds to dextrose vs most other energy sources.

I was a skeptic who preached a strict calorie counting gospel until I heard a famous endocrinologist speak on sugar vs. calories in general. It changed my mind.
 
Hey Bill-

Yes on the unraveling (I was hesitant to post my reply). Also, very good point on sugar, but people lump all "carbs" as bad often which is just not the case and was the point I was trying to make.

People eating slabs of fatty foods, but limiting their carbs thinking they are being healthy is just silly but far too common these days it seems (not that anyone on here would think that way). I think for the most part, pilots and builders are far more thoughtful/discerning than the general public.

As a side note- I eat a ton of carbs, probably 30+% of my daily caloric intake. I am 6'4" and about 173lbs (I've been 220+ before too). I run 50-80+ miles a week and live a pretty active lifestyle outside of that too, but still need to eat sensibly on all caloric intake. I can put on 10-20 lbs in no time if I maintain the same exercise program, but don't watch what I eat.

There are no magic bullets- Like most things in life- moderation is a good rule of thumb when it comes to eating and types of foods.
 
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Thank you

Can always count on pilot buddies to point out how I can improve my life. Good looking out guys. Ha! For what its worth though, I was 275....so I am trying for all the reasons you guys mentioned.

Thank you for all of the valuable feedback on the CG/weight and balance issue. The RV-10 is exactly the kind of plane that I would love to have. It fits my mission. I have pondered whether or not to go this route or just buy a certificated plane many times over the past couple of years. Each time I convince myself to not go with the -10, I manage to come right back around to it......like its calling my name or something. Ha! At the same time, I fully recognize the huge commitment and thinking through every potential hiccup is a big part of the decision process. I am pretty dang close to finally pulling the trigger. Thanks again fellas...
 
:) Congrats! that is solid progress.

You can't go wrong with a 10! Let us know where you live and I am sure someone will be more than happy to take you for a ride. They are all wonderful airplanes.

I am very close to finishing my 7A but I am already planning on doing a 10 in the next year or so.
 
Pilot weight isn't the only thing creeping scarily upward at my house.

I just notified Gallagher that I needed to raise my builder's risk hull coverage amount again. The equity swells more rapidly as the end nears - avionics and interior will be a bigger hit than engine and prop!
 
Threat of a thread derailment :eek: but... calories consumed and burned is indeed the calculus for weight maintenance/loss, but table sugar is a special kind of bad independent of its caloric content. It's in how the liver responds to dextrose vs most other energy sources.

I was a skeptic who preached a strict calorie counting gospel until I heard a famous endocrinologist speak on sugar vs. calories in general. It changed my mind.

For those who don't know, Bill Boyd is rather modest, but his proper name is Dr. Boyd, MD. He knows of what he speaks! Plus, his an all around great guy!
 
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I just ran the numbers for my RV-10 with 1 & 2 250 lb people in front. I won?t post the plot because it?s a pain to post pics on here.

1 250lb pilot full fuel to empty

2266lbs 108.38 CG
1906lbs 108.28 CG. So it moved fwd .1 inch

2 250lb pilot/co

2516lbs 108.99
2156lbs 109.01. Moved .02 inches aft

FWIW

TJ
 
My perspective

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.

I look at it this way: If I lose 50 lbs then that "pays" for my future A/C system :D
 
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.


You are 100% incorrect. You also probably believe the BMI number.

Here is a little example for you.

Male person A is 6'0" and weighs in at 200 lbs. His BMI is 27.1. By BMI and FAA standards, he is overweight.

Male person B is 6'0" and weighs in at 200 lbs. His BMI is 27.1. By BMI and FAA standards he is overweight.


Person A is an Olympic Gymnast.

Person B is a couch potato, watching TV with a bag of chips and a beer.

BMI tells you ABSOLUTELY nothing about your health...it is a simple height weight chart. It does not take into account ANYTHING else...like bone density, muscle mass, body fat or lean body mass.

What difference does it make? Well, the FAA has been having a cow over sleep apnea as of late. What is the FIRST thing they look at?...BMI...and there goes your medical, even though there are at least 17 other things they are supposed to look at.

I take this "health" discussion to heart as I have always been, shall we say, XL. To the point of going in to a specialist, having all sorts of measurements and displacement tests done. Long story short, I will NEVER be in the normal range of the BMI; if I was, they said I would likely lose my medical due to malnutrition...

I do try and watch what I eat and I run on an elliptical 4 times a week for an hour and lift weights. I am no body builder or Navy Seal and yes, I could stand to lose some more weight. The point is, there are those of us who will NEVER fit into that standard mold...I am ok with that. Don't judge the rest of us based on a flawed model.
 
Getting a kick out of this thread! To introduce myself, I’m planning on ordering my RV-10 empennage kit tomorrow...but I’m a repeat offender (I have an 8 that I built and love). I’m a big believer in time restricted eating. I try to eat all my food in an 8 hour window. That trains your body to manage it’s blood sugar and insulin levels which aids greatly in weight management. It works great for me, YMMV.

Mark
 
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