ACA 7GCBC/GCAA Useful Load

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WheelSpatz

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Joe
Hello All. I have been googling my brains out on this one and can't seem to find any solid numbers.

This seems to be an Enigma. State secrets are easier to discover. ADs on Barnstromers or Trade A Plane/Controller do not list. Are they that bad???

I would like to know useful load numbers for Citabria/ACA aircraft in the 7 series. NON Aerbatic! 7eca, 7gcbc, 7gcaa.

The goal is buzzing grass strips and camping east of the mississippi. Not STOL or extreme "backcountry" type ops. Can 2 adults and gear fit or not?
 
Depends on what you mean by gear. Baggage is not that large, and if they don't have the optional baggage door, hard to reach. I haven't run the numbers on my 7ECA, but I usually only so full fuel when solo, and no more than half with two.
 
My useful load is 526 lbs. My girlfriend and I have taken my plane on a couple of overnight trips.
 
midwestpa24 said:
Depends on what you mean by gear. Baggage is not that large, and if they don't have the optional baggage door, hard to reach. I haven't run the numbers on my 7ECA, but I usually only so full fuel when solo, and no more than half with two.
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Backpacking gear.
 
aftCG said:
My useful load is 526 lbs. My girlfriend and I have taken my plane on a couple of overnight trips.
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What model is that? Wood or Metal?

I’ve seen the published numbers from ACA but am curious about real world weights.
 
Beware the published numbers. The airplanes tend to be heavy and the useful loads can be small. The older airplanes are definitely limited. We had a 1976 7GCBC that had been upgraded to the metal spars, and I found that the W&B hadn't been redone to allow for the heavier wings, and the airplane was around 112 pounds heavier than the original W&B stated. I couldn't believe that all that came from just the spars. 20 pounds, maybe. I re-did the fabric later on and saved maybe 15 pounds when I got rid of the Blue River system it had on it. And that airplane had the upgraded struts to raise the empty weight, too.

We couldn't put two 190-pound guys and full fuel aboard either the 7GCBC or the 1996 7ECA. No room for gear at all that way. Big, useless baggage compartment.

If it's an older airplane I'd want an actual W&B done. I wouldn't trust the original or any amendments to it.

From https://www.aopa.org/community/flyi...ewsletter/2016/december/27/aircraft-spotlight

"The club’s new 150-hp Citabria cruises at about 105 mph, while the old 115-hp aircraft had a cruise speed closer to 95 mph, so it’s not going to get you anywhere fast. The useful load is about 450 pounds in the 150-hp version and about 500 pounds with the 115-hp engine."
 
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Dan Thomas said:
Beware the published numbers. ...
If it's an older airplane I'd want an actual W&B done. I wouldn't trust the original or any amendments to it.
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I would recommend that for any older airplane. We had radios replaced (had tube-type Narcos!) and the old radios and power supplies were amazingly heavy. Saved 20 lbs. or more. I didn't think to look at the W&B at the time, then found out that they didn't weigh it, or even note the difference, so technically we couldn't use it.
 
When I looked at the 7GCBC last year, I found you can haul full fuel, a pair of 150-160 lbs humans, and maybe a 20-30 lb bag tops. Have you flown one yet? They are a blast!
 
WheelSpatz said:
What model is that? Wood or Metal?

I’ve seen the published numbers from ACA but am curious about real world weights.
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My plane was born as a 7ECA and technically still is. But it has an O-320 on it, so it identifies with 7GCAA types.
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I do a lot of motorcycle trips so I'm scratching my head regarding the "useless baggage compartment" thing. Assuming you don't need a walker to get around it's no issue. Plenty of space even if you're traveling with a woman who likes stuff.

Wood spars and will be staying with wood. Don't bang the wing tips on the ground and they'll be fine.

For every time I wish it was IFR, had at least one more seat or was 30 knots faster are several solo flights with the throttle pulled back to 90mph - with my elbow out the slider window, burning 4 gallons/hr.

Simple as a wood stove.
 
aftCG said:
My plane was born as a 7ECA and technically still is. But it has an O-320 on it, so it identifies with 7GCAA types.
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Ours is the same. I've never flown a true 7ECA, but the 150 hp seems just right. Not underpowered, not overpowered. Ours has the longer gear legs, 8.50x6 tires, and VGs. A previous owner wanted a bush plane I think.
 
aftCG said:
My plane was born as a 7ECA and technically still is. But it has an O-320 on it, so it identifies with 7GCAA types.
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I think we can call it "type certificate neutral," with a "non-bianary STC," because it's "engine inquisitive."

Totally for the sake of awareness and not being a bully, I am an ally.
 
aftCG said:
I do a lot of motorcycle trips so I'm scratching my head regarding the "useless baggage compartment" thing. Assuming you don't need a walker to get around it's no issue. Plenty of space even if you're traveling with a woman who likes stuff.

Wood spars and will be staying with wood. Don't bang the wing tips on the ground and they'll be fine.
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The useless baggage compartment is because you can't carry bags with a couple of bigger (today's normal) guys. In some models you can't even get full fuel in with those guys.

The wood spars suffer from much more than just ground strikes. The AD and its referenced service bulletin, if you read them, talk about it. The spar flexes under load, of course, and the top compresses and the bottom stretches. There are plywood doublers glues to the spars at the root and strut fittings, and the compressing and stretching is interrupted at those points. The compression is a big problem, as the stresses pile up at the ends of those doublers and causes small compression failures in the wood grain there, eventually weakening the spar, and some failures have occurred. I was involved in replacing the wood spars in one of these airplanes, and we found cracking in the old spars.

Another problem is the shrinkage of the wood with age. The ribs are aluminum and don't shrink, and they are fastened to the spars with brass nails through flanges on the ribs and into the wood. The spar's width (top to bottom) decreases with shrinkage, and since those nails are held firmly in locations by the aluminum ribs, the spars crack at the nail locations. The woodgrain is forced apart. Since that grain structure is responsible to keep the top and bottom of the spar in proper relationship for strength, this is not good. If the nails all fall out of a rib, the rib starts chomping into the spar.

The AD: http://www.airweb.faa.gov/Regulator...951F592569098C7386256A63006A765F?OpenDocument

The Service letter that came out before the AD: http://www.americanchampionaircraft.com/assets/sl406a.pdf
 
Thank you all. I’m mostly concerned with ACA metal wings built in last 25 years.

550-650lbs seems like the norm with 7eca and 7gcbc high country taking the top prize.

Also, doesn’t the metal retrofit increase gw on the older models?
 
WheelSpatz said:
Thank you all. I’m mostly concerned with ACA metal wings built in last 25 years.

550-650lbs seems like the norm with 7eca and 7gcbc high country taking the top prize.

Also, doesn’t the metal retrofit increase gw on the older models?
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I just went looking for a Service Bulletin on that. Couldn't find it. I think it might be in the Airworthiness Limitations section of the maintenance manual. It involved new struts, at least, and perhaps the metal spars too. The 7GCBC spars have long aluminum doublers at the strut attach points to increase the strength. Watch that the inspection hole cover tabs aren't chafing on those doublers; I had to replace the doublers in one wing due to that. They were notched by the tabs vibrating against them.
 
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