STC weight limit problem about light sport.

You are correct weights above 1320 pounds would require a model change. However much more than just a weight increase is required to change from a C to a later model. A CD is an easier change. Due to the difference in airframes.

The STC for the E model elevator does not change the model designation of a C ,CD or D model.

Is there any feedback from Ercoupe pilots whether this STC achieves better pitch control at low speeds?

I don't believe that anyone here said the 415C was an LSA. It can be operated by a sport pilot as it's performance falls within the parameters that a sport pilot can operate. So, as long as it's under TDS A-718, that holds true. Modifications can be made to a higher gross weight than 1320 lbs, but as I understand it, it also changes to the TDS A-787 and becomes a D model or higher. That's why they can't go back to light sport operations. My question was whether the E elevator and 20 deg of travel put it into the D model or no longer eligible to be operated by sport pilots which was answered below.

A technical point that seemed to be overlooked in the Forum. None of the Ercoupes/Aircoupes; regardless the Type Certificate Data Sheet (TCDS) they were certificated (A-718 or A-787) under are Light Sport Aitcraft! All Coupes are certificated, Standard Category Aircraft! With that said only Ercoupes certificated under TCDS A-718 are eligible to be operated under the Sport Pilot weight and speed limitations. The aircraft by STC ( Supplemental Type Certificate) may be modified per the STC which amends that particular aircraft's TCDS.

LSA are not Certificated in a Standard Category. They are issued an airworthiness certificate based on ASTM standards. These standards are based on consensus as opposed to regulatory standards.

Arlan
415-CD SER# 4690
N3989H

That is an interesting question, the light sport aspect. The 415C (gross weight <1320 pounds so they can be flown by light sport pilots) was manufactured under AIRCRAFT SPECIFICATION NO. A-718. The 415D and E ( gross weight >1320 pounds so can NOT be flown by light sport pilots) were manufactured under AIRCRAFT SPECIFICATION NO. A-787. The allowable gross weight is the determining factor for Ercoupes and their eligibility to be flown by light sport pilots. So the question is, can an elevator from a 415E be used on a 415C without automatically increasing the allowable weight to 1400 pounds? Perhaps someone that has purchased the E-elevator STC can tell us if the STC included an automatic weight increase. When it comes to our airplanes and use by light sport, allowable gross weight is always the determining factor. If you do anything to your 415C that legally allows a gross weight of more than 1320 pounds, your airplane can no longer be flown by light sport pilots....for ever.

As for un-stallability, the ercoupes were not certified as un-stallable. They can be stalled, although in reality, they just kind of mush along partially stalled, it doesn't feel like the traditional stall of other airplanes. The E model elevator allows for a greater elevator angle without exceeding the critical angle of attack because the elevator is cut away where the prop wash would normally hit it. Hence, the stalling characteristics are similar for all models. Although all the Ercoupes are not certified as un-stallable, they are certified as characteristically incapable of spinning, the E model and rudder pedal models included.