Champ 7EC Gross Weight Increase

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Steve53

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Indiana
I have a 1959 Champion 7FC that was converted to a 7EC. It has the no-bounce gear. The TCDS says the 7FC and 7EC are both eligible for a gross weight increase to 1500 lbs. 7FC lists two service letters which explains the procedure. 7EC is more vague. My airplane serial number for the 7FC falls in the range where it can be done. My airplane has the American Champion wings and with some other things it’s gotten quite heavy. Useful load is only 367 lbs which is not good. 50 lb increase would help a lot. Has anyone out there done this that can share the process?
 
I take it somebody got it on a set of scales? That seems to convert most older Champs and Cubs to single place aircraft.
 
I don’t have access to them. They are referenced as Champion Service Letters numbers 45 and 46 in the TCDS under the 7FC information. CalledAmerican Champion and they thought they could come up with the Service Letters since they are the TC holder. Even gave them my credit card info for the letters and mailing but haven’t heard anything for a month. Probably not going to at this point.
 
J3 Cubs and 7AC Champs gain a hundred pounds when weighed. We have no idea why - it does not seem to happen for Citabriae. If your mechanic then enters the rsults in your logbook, or worse, on a 337, you are toast.

If the weigh-in does not get memorialized, you can legally compute your weight, using your original factory weight. If you do that, you can legally carry two adults and some fuel - usually.

They do get heavier over time - mine has a starter, wing tank, radio, Grove brakes, and PA-11 struts. All were added arithmetically. I still have a legal payload of 470 lbs.
 
Bob Turner said:
J3 Cubs and 7AC Champs gain a hundred pounds when weighed. We have no idea why - it does not seem to happen for Citabriae. If your mechanic then enters the rsults in your logbook, or worse, on a 337, you are toast.

If the weigh-in does not get memorialized, you can legally compute your weight, using your original factory weight. If you do that, you can legally carry two adults and some fuel - usually.

They do get heavier over time - mine has a starter, wing tank, radio, Grove brakes, and PA-11 struts. All were added arithmetically. I still have a legal payload of 470 lbs.
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Yeah you’re right. I weigh 195 which leaves enough for a very small person in back and maybe an hour of fuel with reserve.
 
Not completely. The SL calls out axle p/n 4-1139. That is the axle on the "no bounce gear", The oleo is different.
As usual it is clear as mud. Your IA will need to sort out what he is comfortable with.
 
Sully said:
Not completely. The SL calls out axle p/n 4-1139. That is the axle on the "no bounce gear", The oleo is different.
As usual it is clear as mud. Your IA will need to sort out what he is comfortable with.
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There’s someone on eBay selling what’s described as Aeronca Wide Gear fittings but the part number that’s listed is 1-9145. They’ve attached a diagram but I couldn’t open it to see what it is. They have 4 to sell.
 
Does anyone know why 7FC earlier than SN347 are not eligible under SL 46? Is there any approvals to convert 7EC to 1500 lb GW...actually 7FC converted to EC. Since mine has an O-235, I need to scrape up every extra lb of payload I can get!
Thanks!
Larry Lowenkron
7FC/EC w/O-235
 
There are a couple changes to the frame after a certain serial number range, if earlier there’s a tube to add to the bow, and a gusset or doubler/plate and something else besides the gear for the increased gross weight. Here’s a link to the letters with the conversion information, remember reading about it when checking to see if my 7AC to EC conversion was fully complied with since it only had the engine conversion on the 337, rest was never filled. So I had a light sport legal Aircraft with a 1500lb theoretical gross weight.

 
There is a note in the type certificate (Note 15) that explicitly says that any 7ECA with factory metal spar wings has a limit of 1750#.

There are other confusing issues - one is that in the bird I am working with, a 200# pilot and full fuel (35 gal) is out of forward CG.
(flies fine). The limitations section of the POH disagrees with the type certificate on the forward limit for the GCAA.
 
Bob Turner said:
There is a note in the type certificate (Note 15) that explicitly says that any 7ECA with factory…
Click to expand...
I guess I’m confused on the question, are you wondering about the TCDS cg range for the GCAA vs the current POH? Was this a conversion? The TCDS is the law unless there is a STC or SB that directly tells you to modify the CG range, POH is normally a poor resource unless it specifically has that aircraft’s model and S/N on it directly from the factory and no major modifications, not just a universal one added. Some mods will have you change rigging, or a control surface change, hence the change in CG range. Also note 15 can only apply to the noted S/N airframes not just any ECA or GCAA. Earlier than that, even with the new wings, still the original weight.

Also remember they were made for 160lb pilots… so might have to move your battery farther back or get a lightweight oddesy if it’s a firewall mount. Easy way to save 10lbs
 
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