Max Weight for Aerobatics

+6 -5 G’s said:
Try flying with 1/4 tanks of fuel....you’re below the weight andCG limits...hack the clock on takeoff....go fly 30-45 minutes and don’t worry about it!

These planes don’t recover well when they are overweight and out of CG....

IMHO...YMMV
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Fortunately, I can still fly the standard decathlon as an option. It's just the super decathlon where I am weight challenged. Most exciting is that my local flight school just found a 115 pound aerobatic flight instructor. WooHoo.
 
Big Ed said:
Google some images of Greg Koontz; the guy is a hoss.
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for a while there I was hoping Greg would visit from time to time but not anymore! I am not sure how I would explain that! lol

the relationship between max gross and g limits would seem to make sense but being over gross at 1 g and in an awkward base turn to final could ruin one's day, IMHO
 
with ACA shoehorning an even heavier IO390 into an 8KCAB, they had no choice but to find weight reduction options otherwise the limited useful load problem would have been worse! the aluminum gear, the new ailerons, CF floorboards, composite prop.....even the flat wingtips were part of the effort. All of those mods are backwards compatible to Bellanca 8KCABs but they get expensive.
 
Bartman said:
for a while there I was hoping Greg would visit from time to time but not anymore! I am not sure how I would explain that! lol
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LOL, where Greg is from in Alabama, "hoss" is a high compliment. I've never met him, but from photos he appears to be several inches north of 6 feet, and solidly built.

The last time I weighed under 200 pounds was in college. I have flown acro with several CFIs who were at least as big as me. Never saw a scale or discussed bodyweight. We all used half tanks for acro.

Speaking of which, does anyone have tabs in their tanks? I seem to recall having tabs in my old 77 Decathlon CS, but not in my 78 Super D
 
Bartman said:
the relationship between max gross and g limits would seem to make sense but being over gross at 1 g and in an awkward base turn to final could ruin one's day, IMHO
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A metal wing 8KCAB with steel gear has a max gross of 1800. The same plane with aluminum gear has a max gross of 1950. What is it about the landing gear that makes you safer turning base to final?

The answer of course is nothing. The original max gross was limited at least partially by gear length and the potential for a prop strike on a hard landing.

I don't want to set myself up as the reckless advocate for blindly ignoring operating limitations. But, max gross is a big constraint in Decathlons, and if you adhere strictly to the limit you are going to cancel a lot of flights. For example, in my plane I am over gross with myself, full tanks, and a 25 pound bag, which would pretty much rule out XC trips. IMO an understanding of the actual impact of small amounts of excess weight is essential to make responsible decisions.

It would be interesting to see how professional pilots like Greg K and Patty W handle gross limits during dual, since they have built a business around the Decathlon. I suspect it is keeping pulls under 4.5G and "don't ask, don't tell."
 
You guys need to look at a Super Cub with Wipline amphibs. I remember one coming from Cub Crafters that could legally lift a 145 lb pilot with enough gas for one trip around the pattern and VFR reserve.
Their 2000 lb gw STC cured it, but you know a lot of those airplanes flew with two folks and lots of fuel before that.
 
As forum administrator it is my obligation to post information that is in line with the TCDS, operating manual, etc. It makes me look like a major dork sometimes but it isn't as bad as what might happen if someone accused me of encouraging an environment here that ignored our official sources of information.

I thought the aerobatic gross weight is 1850 and max gross utility weight is 2000, no? the wing and gear gross weight increases don't increase max acro weight, afaik.

The gear don't help turning final but when the plane is slow and being operated at it's lower performance limits, the extra weight isn't offset by the plane's g tolerance, it's the higher stall speed and possible aft CG that are waiting for you to mess up. I am not intimately familiar with the plane's performance and loading limits other than what is published. I'd guess Jody, Dale, and/or Jerry Jr. would know (and that hoss, GK!) but I'd also guess they'd never offer anything other than what's published.

Dancing chicken for "major dork" reduction effect :DC: (although maybe it makes it worse???)
 
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8KCAB aerobatic max gross is 1800. For wood wing, steel geared 8KCAB, that is also the normal max gross. For an aircraft that has BOTH the metal wing and the aluminum gear, the normal max gross is 1950.

Put metal wings on my airplane, the max gross stays at 1800. Then put aluminum gear on, and the max gross goes up to 1950. The aluminum gear does not change the stall speed or flying characteristics. That tells me that stall speed is not a concern at 1800.

Here are some load charts for my aircraft. First is with me, full tanks, and 25 pounds of baggage. Aircraft is 20 pounds over gross on takeoff. CG is towards forward limit. IMO the only concern with this configuration would be accuracy of takeoff performance charts.

XC cropped.png

Here is one for dual acro, with 220 pound pilot in front, 200 pound CFI in back, and 20 gallons of gas. Aircraft is 75 pounds over gross at takeoff. Note that it is still over gross at landing with 10 gallons of gas.

acro dual cropped.png
 
Big Ed said:
The aluminum gear does not change the stall speed or flying characteristics. That tells me that stall speed is not a concern at 1800.
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I didn't say the gear changes the stall speed, I said loading the plane over the max certified gross weight does. :)
 
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Bartman said:
I didn't say the gear changes the stall speed, I said loading the plane over the max certified gross weight does. :)
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If max certified gross weight changes from 1800 to 1950 with new gear, then loading it over 1800 does not result in unsafe stall characteristics.
 
Ed, you're absolutely right. If there's a gross weight margin over the acro limit then you're covered in that weight range for whatever the airplane is certified to do.
 
Bart is correct - really none of us should publicly be advocating flying overweight, or breaking any regulation. We all have responsibilities to society to not encourage lawlessness.
That doesn't mean we cannot confess to a deviation (be sure the statute of limitations has expired) or discuss others who have broken a reg. Just don't name the guilty party - nobody needs a lawsuit.
 
I don’t have a max weight problem, I have an aft CG issue with the aerobatic envelope with my wife in the front seat. Looks like I need to place 22 lbs in the front seat pan to teach her aerobatics. Not sure she would like to rear cockpit to much. All good in Normal Category. 844E5508-58C1-444B-B27A-DA3F75202D06.webp
 
@VaporGlobalAviation Do you have a 7ECA? If so, I wonder if your w&b profile has a mistake. I was looking at the FAA TCDS for the 7ECA and the aft limits should be 17.3 at 1650, 17.3 at 1325, and 17.3 at 1250. That might bring you in CG if my hunch is correct. If so, your wife will be happy getting to keep the front seat!
 
towpilot said:
@VaporGlobalAviation Do you have a 7ECA? If so, I wonder if your w&b profile has a mistake. I was looking at the FAA TCDS for the 7ECA and the aft limits should be 17.3 at 1650, 17.3 at 1325, and 17.3 at 1250. That might bring you in CG if my hunch is correct. If so, your wife will be happy getting to keep the front seat!
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Yes, 72, ECA

I am going to double check that, thank you. When I was in the market I was looking at both Decathalons and Citabrias. I made profiles for both so I knew before purchase how things would look. I may have missed something. This profile is certainly more conservative. I have a little bookwork for tomorrows blizzard.
 
It's worth pointing out also, our W&B charts use total weight and total moment where the Cessna charts that a lot of us learned on use total weight and calculated CG (in. aft of datum). that's the mistake I initially made, looking at the Citabria chart like WTF?? before I figured out I was reading it wrong.

edit: i see you're using a program so this isn't an issue, carry on! lol
 
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When it comes to weight and balance, I have seen so many errors done by competent mechanics and FAA repair shops that have scales and computers that I always go back to first principles - and for Cubs and early Aeroncas I try to start with factory weights so we can have a 2PCLM when we are done.
 
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