Is there a “best” CG?

[RV6-KPTW]

I have held a simplistic, idealized binary view of CG: In good, out bad. Perhaps it is more nuanced?

I am building a 10 and have some choices to make. Is it better to be forward or better to be aft? Should there be guardrails for the CG envelope? Put some slop around the values used? I should consider warning value ranges that inform me that we might be approaching one of the edges?

I searched VAF and got lots of returns (did my homework) but I am not sure anyone has talked about CG being a range and the value of being at 50% or 75% or whatever.

I am sure you have thoughts.

Thanks

 

[Norman CYYJ]

I have held a simplistic, idealized binary view of CG: In good, out bad. Perhaps it is more nuanced?

I am building a 10 and have some choices to make. Is it better to be forward or better to be aft? Should there be guardrails for the CG envelope? Put some slop around the values used? I should consider warning value ranges that inform me that we might be approaching one of the edges?

I searched VAF and got lots of returns (did my homework) but I am not sure anyone has talked about CG being a range and the value of being at 50% or 75% or whatever.

I am sure you have thoughts.

Thanks

You want to stay neutral or forward, never outside the aft limit. Aft is fine while cruising but it can get pretty exciting on landing or slow flight and stalling.

 

[Mel]

Forward is "stable"...Aft is "maneuverable". Most people prefer "stable". I prefer "maneuverable".

Cross-country, stable. Fun flying, maneuverable.

 

[skirting_virga]

You want to stay neutral or forward, never aft. Aft is fine while causing but it can get pretty exciting on landing or slow flight and stalling.

Aft is more sensitive in pitch and makes for potentially less trim drag. Some less desirable characteristics come with that, but I appreciate operating in the middle of the envelope vs forward sometimes. I can land slower even when heavier, with mid-aft cg.

 

[rmarshall234]

Unsurprisingly…the answer is a familiar one in aviation..”it depends on your mission”. I built a plans built aerobatic biplane and had almost complete control of where the empty CG would wind up. But not so much the envelope. I asked one of the guys that had flown Sean Tucker’s Oracle Challenger III how aft the CG was on that biplane and his reply was “stupid aft” . Now I”m clearly no Sean Tucker but an aerobatic airplane should be very responsive so I built mine so that with 20 gals of fuel and me on board, I am smack dab in the middle of the range. I am reminded of that every time I land it

 

[Kyle Boatright]

On the -10, anything you load in the airplane moves the CG aft. When we go to Oshkosh with 4 adults and 70-80 pounds of baggage we end up in the aft 20% of the CG range for the whole trip. The airplane flys very well in that CG range and it is a bunch easier to hold the nose gear off the runway on landing. The empty CG on my airplane is 107.25 with an empty weight of 1607 lbs. Bottom line for me is a forward CG is better. You can always throw a case of oil in the baggage compartment to move the CG aft when flying solo, but if you're gonna carry 4 people and baggage, you need to start with a forward CG.

 

[BobTurner]

On the -10, anything you load in the airplane moves the CG aft. When we go to Oshkosh with 4 adults and 70-80 pounds of baggage we end up in the aft 20% of the CG range for the whole trip. The airplane flys very well in that CG range and it is a bunch easier to hold the nose gear off the runway on landing. The empty CG on my airplane is 107.25 with an empty weight of 1607 lbs. Bottom line for me is a forward CG is better. You can always throw a case of oil in the baggage compartment to move the CG aft when flying solo, but if you're gonna carry 4 people and baggage, you need to start with a forward CG.

+1
There are quite a few -10's out there that are limited by aft cg, rather than weight, when you try to add people and baggage in the back.
Kyle is right, if solo you're near the forward limit, it's easy to add weight in the back (I use a 20 lb water jug. If I have passengers in the back I drain out the water.) But if you're past the aft limit, only thing you can do is move bags forward to the passengers' feet!
Another tid bit. The -10 has the quirk, that if you take off with the CG close to either limit, then, as you burn gas, the CG moves closer to (or even beyond) that limit (!) My CG spreadsheet automatically calculates zero fuel CG, and lets me know if that is out of limit. I've made at least one trip where I had to land with at least 20 gal on board, or be out of aft cg (or get a heavier passenger in back to swap seats with the lighter passenger in front).

 

[rvbuilder2002]

If an RV-10 isn’t slightly annoyingly nose heavy with full fuel and only the front seats filled, then a lot of the utility for carrying people and baggage that the RV-10 was specifically designed to maximize, is being sacrificed.
It is no difference from another popular load hauling airplane, the C-182. Except with the 182, since the control forces are a lot higher, you are actually thankful you have a control yoke in front of you because you will be using both hands to flare during full flap landings.

 

[BobTurner]

Except with the 182, since the control forces are a lot higher, you are actually thankful you have a control yoke in front of you because you will be using both hands to flare during full flap landings.

Well, no. You can start the flare with just your left hand, while your right hand madly rolls in more nose up trim. Now, if a last second go-around is needed, now you need both hands pushing forward!