Hi, considering the purchase of a 7GCBC and would like to install 8GCBC gear on it. I know there have been a few done as 337 field approvals, wonder if the FAA would still approve of the change. As a different option, how much taller is the new factory aluminum gear? Can the new gear be installed on early models via a service bulletin as the approval method. Sorry I went so long, thanks. Tim
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8GCBC gear on 7GCBC
- Thread starter bat443
- Start date
wjwilson2000
New member
Jerry is going to be the man to answer the aluminum gear question for sure. I spoke to him just after they came out with the higher HP 7GCBC. One good thing about the aluminum gear if the plane your looking at has a set of ACA's new wings, with the aluminum gear you would be a lot closer to installing the higher HP engine per their drawings.
Woodie
N29763
Woodie
N29763
For retrofit of the aluminum gear refer to service letter 422 rev A
http://www.amerchampionaircraft.com/tech/techmain.htm
Involves welding a new fairlead in to accomodate the thicker leg. The fabric part is mor painful than the welding since its easy to access the area. The ski fittings you have might not be imediately compatable with the new leg/u-bolt set-up.
Total weight savings is 13 lbs for complete install. The aluminum legs are about 1.25 inches taller than the 7-1404 steel legs.
8GCBC gear legs are not approved for the 7GCBC. There are MANY 337's out there, but this was from when FiSDO did them. An ACO won't be so easy. Basically, its an example of why the FAA is dropping Field Approvals. The FiSDO approved the new legs based on the fact the leg itself is made for a heavier airplane and thicker. Sure, the gear leg is fine. However, it changes the reaction loads on the fuselage. The 8GCBC undercarriage shames the 7GCBC's when it comes to design strength. A longer and thicker leg, not only changes the moment arm that loads are applied, but also changes the energy absorbtion. Therefore, not only are the fuselage loads higher, they are unknown....until you do a drop test.
Now, this is not to say the assembly is unsafe. Its to say, its really not properly certified. In all likelihood, its probably fine, but that won't hold up in court until you know for sure. :wink:
http://www.amerchampionaircraft.com/tech/techmain.htm
Involves welding a new fairlead in to accomodate the thicker leg. The fabric part is mor painful than the welding since its easy to access the area. The ski fittings you have might not be imediately compatable with the new leg/u-bolt set-up.
Total weight savings is 13 lbs for complete install. The aluminum legs are about 1.25 inches taller than the 7-1404 steel legs.
8GCBC gear legs are not approved for the 7GCBC. There are MANY 337's out there, but this was from when FiSDO did them. An ACO won't be so easy. Basically, its an example of why the FAA is dropping Field Approvals. The FiSDO approved the new legs based on the fact the leg itself is made for a heavier airplane and thicker. Sure, the gear leg is fine. However, it changes the reaction loads on the fuselage. The 8GCBC undercarriage shames the 7GCBC's when it comes to design strength. A longer and thicker leg, not only changes the moment arm that loads are applied, but also changes the energy absorbtion. Therefore, not only are the fuselage loads higher, they are unknown....until you do a drop test.
Now, this is not to say the assembly is unsafe. Its to say, its really not properly certified. In all likelihood, its probably fine, but that won't hold up in court until you know for sure. :wink: