Ercoupe 415-C 9CF Baggage Compartement STC and 1320lb Gross Weight STC

Its not “stainnless steel cowl cover”. It’s the panel over the header tank. Between the windshield and the firewall.

Converting to a D has NOTHING to do with the firewall!! It’s the skin that covers the cowl tank. It must be stainless. It also has nothing to do with the gas tank. You must:

Put a stainless steel skin over the gas tank

Make sure the orifices in the MLG are correct

Limit elevator up trsvel to 9 degrees

Have the ¾” trim tab

I believe these are required for the 1320 STC with the possible exception of the stainless steel skin.

Surely somebody must remember what to do. As far as I know an approved 337 is all it takes. Many C models were converted to D models to get that extra 140 pounds! A lot of people bought Ercoupes that were registered as 415C models and later got the FAA CD and were shocked to find the 337 that converted it to a 415D! At the time that meant a sport pilot couldn’t fly it (no longer the case).

I'm half way through the 1400 pound increase. I have the 337 approved but so far i can't figure out how to change the designation with faa. I contacted a dar that I've used previously and he said he needed to research it. If you know how that step is completed, I would live to know

As I understand it, There is a certification requirement that the firewall not be aluminum. During certification, there were numerous modifications, one being the larger cowling that extended over the gas tank with only an aluminum sheet separating the passenger compartment from the engine. Nobody thought about how that compromised the "firewall" separation. The inclusion of the steel sheet in the STC is to correct that oversight.

i am curious to understand how changing the stainnless steel cowl cover affect the capacity of the ercoup to carry more weight

Sorry I'm so late responding! Why buy the 1320 STC when you can just upgrade your coupe to a D model and have a gross weight of 1400? MOSAIC lets you fly it! You get 80 more pounds and the only difference in requirements between the STC and the D model conversion is the stainless steel cowl cover!