Kim,
There are some minor differences in the aircraft between the 415-C and 415-
CD versus the 415-D. They are things like making sure the aircraft had the
larger aerodynamic trim tab, larger orifices in the landing gear shocks and
a few other things. These are detailed in TSDS A-787 NOTE 3.
http://edburkhead.com/Ercoupe/A-787_Rev_33_2005.pdf
Most of these things were already incorporated into the later serial number
415-C models and all were factory installed in the 415-CD models (whether
when built or by a factory upgrade in the field that changed the "factory"
model).
The main difference IS regulatory. The 415-D was certificated under later
regulations. I ***think*** a key difference was that the later regs
allowed a lower g-load structural strength compared to gross weight and
imposed extra limits on unusual flight regimes. i.e. 4.5g design strength
instead of 6.0g IIRC and the later models were prohibited from aerobatics.
[Not that performing aerobatics in a 415-C is anything but VERY dangerous,
IMHO.)
In addition, the FAA in its infinite wisdom (Read Bill Bayne's acerbic
description of the details of this sometime), the FAA decided to restrict
the higher gross weight models to an elevator up travel of only 9˚ instead
of the 13˚ allowed in the earlier models.
If you install the 1320 pound STC, you will be making all the same changes
as would have converted it to be a 415-D but without actually making a
model conversion. Via the STC, you get 1320 pounds of gross weight without
losing LSA status.
Saunders came up with the "split" elevator that allowed the slip stream to
go through the cutout, so the slipstream affects trim almost not at all.
As I said a couple of days ago, this gave these results:
13˚ up travel 48-52 mph landing speed 415-C and 415-CD
9˚ up travel 55-60 mph landing speed 415-D and on earlier models
with 9˚
elevator limitation due
to using
the 1320 pound STC
20˚ up travel 48-52 mph landing speed 415-E and all later models AND
earlier
models with split elevator
installed
via STC or field approval
on a form
337
Sorry they gave you a shoddy accident investigation on your old Coupe. I
suspect they just couldn't find any cause at all.
Ed
