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weight and balance

Lan Vinh Do

Lan Vinh Do

Well Known Member
Hi
I am about to make a trip with 4 adult and luggage baggage.
I have a mt prop and a 02 tank in the tail so my cg is probably more aft that others and as i burn fuel, my cg go farther back.

When i calculate my w&b i am ok on take off but if i land with only 10 gal, i will be 0.2 inch pass the aft limit.
My queation is : is the 114.58arm for pilot and copilot is calculated with the pilot seat completely at the rear position. I am only 5feet 7 and i always put my seat the more foward i can. So of i put the pilot front seat at 112.58, i am ok.

if not, anything bad to land with a cg 0.2 inch aft of the rear limit?
 
I cannot answer your question. I am an RV7A Driver.
I can ask another one: Have you ever tried landing with a CG too far aft? I have in a spam can. I will never do it again. Be careful out there.​
 
"is the 114.58arm for pilot and copilot is calculated with the pilot seat completely at the rear position"

I thought it was an average (middle of the adjustment range) number.
Obviously there are some variations here. If you have the seatback more reclined your cg moves back. If you wear heavy shoes, it moves forwards.
I attempted to put in numbers based on the seat back being as upright as it goes, since that's how I fly. I use 113.3" for me, which is one notch back from full forward.

Yes, with aft loadings the CG moves further aft as you burn gas.

Of course you should put in the proper number for the front seat passenger, too, depending on if he/she is full forward, full aft, or in-between.

Flying with the cg too far aft will display the following characteristics:
1. Aircraft will be very light in pitch, and if cg is really too far aft, pitch will become divergent (small bump raising the nose, nose will continue to rise). It may become uncontrollable by a human pilot.
2. Stalls may become unrecoverable.

If necessary try to relocate some luggage between the two front seats. The other alternative is to make intermediate fuel stops to keep the tanks more full. 10 gal on landing is my personal minimum, regardless of what the FARs say.
 
Weight and bal

Hi
Thank you for the answer. I don't want to scare anybody. My normal trip will put me at 30 gal in the tank so well in the cg limit. I was considering worst case senario. IFR, miss approach, going to alternate etc. If it's low ifr, i will not make the trip as my wife don't like these condition and passergers only flew once before. At 113.3 for pilot and copilot it would be ok even with only 10 gal.
Any other answer will be welcome.
 
Better solution

I will have a good trip. I decided that the wifes can only bring bikini and lace dress. They will never say no if it's for safety.
 
Because I have aux bat beside main battery, I limit baggage to 99 lbs in the rear. Anything else goes in passenger floorboard areas. In cruise if passengers need more leg room they can move it behind them until descent. Being near aft cg limit makes us more efficient in cruise. Don't forget to move it back before landing. The wife keeps purse up front against spar. Whatever you do don't push the limits with friends, use dogfood or similiar as I did.

I heard from a friend...it can make landing very interesting with aft cg. He told me he did not wish to make that mistake twice. I forgot his name.
 
Aft CG

You really need to treat aft of CG range conditions seriously. Assume 0 leeway. I have flown another aircraft that was either right on or slightly behind the range. I survived but I'll never let that happen again. Rear loading is hairy and scary. Forward loaded isn't scary until you break the nose gear off.

If landing with 10 gals is required to stay within range, you are flying with 10 unuseable gallons so of course you would never plan to land with less than 20, etc.

So here's the deal, if everything goes well, no problem. But if one small misfortune is followed by another, than another, you find yourself now depending on using some of the 20 gallons you didn't plan to use. Then the stuff that was supposed to be move forward as the fuel was burned off is forgotten because of turbulence. Then a passenger gets sick, and the head wind is 10 knots worse than forecast, then the turbulence gets a bit worse, then its hard to hold heading and altitude, then you get fixated on fuel as your alternate closes due to an accident. Then you realize the plane is hard to handle because of an increasingly rearward CG, then you screwed it. No bikini, no lingerie, ever again.

Too heavy, you can often manage. CG to far back, you be scared to death even if no one gets hurt.

I assume you are pulling some leg here but if not, let us know.

Bill
 
If your normal takeoff method is to start with the stick full aft, you might find that with the rear C/G, the nose wheel comes off immediately when you give it the throttle------and you can damage the rudder bottom fairing.

BTDT.
 
I would often be in an aft cg in my 7A so I would limit baggage to 60 lbs.
This would often occur with 10 gals remaining. On landing, I would always have my wife pull one of the backpack bags from the aft section & she'd move it forward.
Another thing I would do is place 12# of scuba bean bag weights onto the inside cabin firewall when I knew we'd be in that situation on a cross country flght.

Probably not the text book way of handling it, but it worked for me.
 
If you have a question about C/G, my question to you would be, "What were you doing during Phase I flight testing?"

You should do nothing, C/G wise, that hasn't been tested before.

As a side note, C/G position for people is normally based on where the "belly button" is, so the angle of the seat back is rarely a factor unless it is very extreme.
 
Phase 1

Hi mel

I didn't do phase 1. I built the 7-a but bought the rv-10
I have 150 hre on it. But no phase one.
 
Since you were not the builder, you may want to recheck w&b. Then load it up with an aware copilot. I would not recommend dogfood/sandbags in front seat as there have been loss of control accidents due to movement in flight. Then load rear seats and baggage area slowly over several flights. You will be surprised at the handling difference from fwd limit to aft at gross weight. If you decide not to do this or just don't have time, then like someone else said...remove O2 bottle and enjoy the scenery/fuel burn down low. Be careful and have fun. We DO want to see a trip report when you get back home!
 
.2" seriously?

No one is going to say in this forum that it is ok to fly outside the limits of
the approved CG range because it reflects badly on the poster.
I can assure you that what has been said is true, having flown hundreds of take offs with cg limits at the rear or aft on many flights. I have also observed
heavily loaded airplanes taxiing out in Anchorage almost dragging their rudders
and done so myself.
I have also tested my RV10 loaded to maximum of 2700lb at the extreme aft cg. during phase one and completed landings and take offs and stalls in this configuration.
On the positive side you will lower your stall speed and improve your cruise speed with a rear cg.
On the downside you will loose some lateral stability but within Van's limits,
the 10 is very controllable at full aft cg.
As to your seat location you can measure the arm and see for yourself where the front passenger CG is located then change it in your W&B set up for your particular seat position. Problem is you will not affect the CG very much by moving weight located almost directly on the CG of the airplane.
This brings me to my point, .2" out of CG range???
Surely you can position a couple of items so as to be within specified limits.
It's a little bit like the airspeed red line, I am sure there is a margin built in
BUT, it belongs to the engineer not to you.
 
didn't went the way it should.

Finally, didn't have to fly 0.2 inch pass the aft CG.
The decision was easy. The trip for the 10 years graduation reunion of my wife didn't gone to happen.
Weather at destination, thunderstorm with cross wind 40kts and wind shear. 30 min in the cloud, in turbulence before to arrive at an airport that i would probably not be able to land and with a aft CG. I could land 80 km from destination and rent a car to avoid the clouds but still a lot of turbulence and cross wind for first time passengers.

Me, my wife and our friends had in mind to pass a week end away. We both had our baby-sitter booked.

So the plan changed from Moncton to Bromont in RV-10 to Local 1hr flight in calm weather as a first flight for the friends and they really enjoyed it. After, we went in our toyota highlander to Halifax NS for the week end and enjoy good diner, Casino and shopping.

The argument for bikini and lace dress wasn't good anymore ( but our wifes are pretty anyway). I did the weight and balance of the toyota highlander and they were not limit to 30lbs of luggage but with 500 lbs, they we were still in cg limit!!

We had a really good week-end with nice friends and nobody had to be scared.

Thank you everybody for all the advice. I found a friend that have some racing scale and I will reweight the rv-10 because I am not sure it has been weight accurately at first.

https://picasaweb.google.com/lanvin...&authkey=Gv1sRgCLzBz6qc_pucIw&feat=directlink
 
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Very Pretty Wifes.

Glad you are home safe.
Next time, just leave that dude home and take one of those pretty wives up front with you, that'll solve your weight and balance issue for sure.
You are a lucky man.
 
I can't

I wish but they are the godfather and godmother of my second son.
I can't leave him on the ground.
 
I just completed 2 straight weekends playing a passenger pilot. I am exhausted! The last flight was a 190nm trip over the sierra nevadas to the nevada desert with 4 adults and full baggage for a weekend trip.

It is quite an adjustment going from flying solo to flying with 3 people new to GA. Pre-flight and safety briefings are longer, dealing with extra weight, noise and voices and the other typical chaos among the excitement. Being responsible for them increases the stress level of the entire flight, etc. Of course, they have no idea what we have to go thru. Just loading baggage for 4 is a chore and not to mention how huge the effects are on CG.

As i knew from my weight and balance exercises, CG is more of an issue than gross weight. Baggage for 4 people has a huge arm which hugely affects CG. Thus, I opted to fly with full fuel and just made sure to top-off when i could.

For the flying part, adjusting for weight was the biggest effect. Takeoff roll is much slower and climb rate is much slower, which is all fairly obvious from a mental perspective. However, overcoming muscle memory was a challenge. I found myself having to force myself to exert less pressure on the flare due to the aft CG. It's interesting just how differently the plane flies and the mental adjustments you have to make.

We were blessed with the best weather all year, which made all the work worth it in the end. Flying over yosemite's half dome and el capitan was a highlight for them, which was great.

Just my 2c.
Jae
 
Balance trouble?

No weight or CG trouble taking this load of 3 adults but
a bit of a "balancing act" explaining it to my wife....
Not to worry, these are 3 of my most talented Pastry chefs all of whom I took out for a birthday flight/lunch. I've done this with most of my 14 employees over the years and many of them have been with us more than a decade.

IMG_2511.JPG


IMG_2512.JPG


Props Restaurant and Lounge, Watsonville CA.
 
Wow...what a birthday! No cabin heat required!

So, how difficult was it to blow out the candles and have cake and ice cream in flight? Bob Hoover poured tea during a loop.
 
I stop trimming around 90 kts and half flaps so that I have to pull through to touchdown. It also makes those infrequent go arounds easier. On takeoff I set my trim down one led more when full.
 
RV 6 weight and balance

I have need of a blank weight and balance sheet for a rv6. If someone could email said copy to I would be of great help,,, mtnflyer@ msn.com. Thank guys
 
Oops, somehow i missed these replies earlier.

Mike and Wayne, that's a good tip. I didn't think of using trim in that way.

Ernst, i still have an unfulfilled fantasy of flying 3 hot women, errr, employees in my plane, too. Looks like you beat me to it! :D

Jae
 
Yeah Ernst

Not fair..... I have not seen such dangerous images since about 2005 when my brother and I did some photos for sponsors calendars.

And while these girls were all known to my wife, she still was not happy about the photo framed on my bookshelf here at work. She eventually got over it. :eek:

DSC00146.jpg


Not managed to do this for the plane.... :rolleyes: idea hatching :D
 
RV-10 in OZ says: "And while these girls were all known to my wife, she still was not happy about the photo framed on my bookshelf here at work. She eventually got over it."

I say: "You just THINK she eventually got over it." :p
 
Rules

A very wise man once said to observe and follow the rules but you should worship the CG..... Especially the aft CG. I would remove the O2 bottle and minimize baggage. I would also load the aircraft with ballast and fly in the desired configurations prior to taking passengers. Remember, if you are in a spin and aft loaded, it may be impossible to recover from a spin. If you are in a spin, the objects may shift and lodge further aft then they were originally loaded. Also if you have something heavy in the rear and you are spinning, it "weighs" more and may make recovery difficult or impossible. Just ask the producers of Top Gun. Watch who the movie is dedicated to and why.
Best.
Brian
 
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