POH'S for both the C and D models came with my airplane.  I believe mine is
technically a D but still don't know why it isn't the same thing as an E. I
don't fly Sport pilot.  Of course in my hypothetical I assumed a full fuel
load as far as taking one of my sons along as an example, and realized I
could fly them on a short flight with less fuel. Each of them have their own
aircraft, twin Cessna 320's. 

I don't trust my fuel gauge since it always seems to read 3/4's full, so
I've sent for a fuel cap described as the "little dipper", to be able to
accurately dipstick how much fuel is remaining. With the high dihedral I
felt I needed something specifically made  to accurately gauge how much fuel
is remaining, so I can confidently take that short flight with them.

Anyway: 914.4 + 7.5 (Oil) + 108 (full fuel in Wing tanks) + 30 (full fuel in
fuselage reserve)= 1059.1.  1400-1059.1 = 340.1 to play with. -160 and I can
take one 180 pounder along with me with no baggage or other added weight
with full fuel. Yet I have heard or read stories about two large dudes
getting in their Ercoupe with their tent and other camping gear and flying
from some other state to OshKosh Wisconsin for Airventure. Must be
hyperbolic Ercoupe folklore. 

By the way, my aircaft burns 6 gals. per hour.         


-----Original Message-----
From: Ed Burkhead [mailto:[email protected]] 
Sent: Monday, December 07, 2009 2:04 PM
To: 'Jack Burwell'; ety
Subject: RE: [ercoupe-tech] Flying the Coupe overweight?



Jack wrote:
> I have a 1946 Ercoupe 415 C/D . . . I can't figure out why it is
> not an E model.

Jack,

Let’s start at the beginning.

Here are the possible model numbers:
415-C
415-CD
415-D
415-E
415-F (stripped down model, very few made, all converted, I think) 415-G

There is no such thing as a 415-C/D.

Note that Type Certificate Data Sheet A-787 does allow a 415-C or 415-CD to
be up-converted to be a 415-D.  No other changes are authorized. (Well, I
guess you could legally change it back but that'd be crazy as, due to the
wording of the Sport Pilot regs, the plane would not be able to regain its
Light Sport Aircraft eligibility.)

If you have a 415-C or 415-CD, then it only allows a maximum gross weight of
1260 pounds, or, if you have the STC, 1320 pounds.

If you have a 415-D, E, or G, or Forney F-1, then you have a maximum legal
takeoff weight of 1400 pounds. The penalty of having your plane converted to
be a D (or later) model is that it loses about $10,000 in value as it may
not be flown with a Sport Pilot or PPouSPp acting as pilot in command.
(PPouSPp = Private Pilot operating under Sport Pilot
privileges.)

(Forney F-1A, Alon A-2 and Mooney A-2A or M-10 models all are allowed 1450
pounds gross weight with, essentially, (Mooney M-10 excepted) same airframe.
However, note that the Forney, Alon and Mooney models all came with the C-90
engine.)

If you do have a 415-C or 415-CD, then it’s nice that it has the
modifications that give you more convenience and features and, in the case
of the split elevator, slightly greater safety.  In no way does it need to
be a higher model unless you want to carry 1400 pounds (in which case you
lose that extra $10,000 in market value).  Each of those mods can be
separately approved for a 415-C or 415-CD.

You’ll note that the models which ARE allowed to carry 1400 pounds are
structurally almost identical to the 415-C and 415-CD with only minor tweaks
in the airframe including either limiting the standard elevator to 9° up
travel.  The Split elevator gets the same job done with even greater safety
(as it returns the touch down speed to the original designed touch down
speed).

There’s no doubt Marv does know his stuff.  Me, I did not fly outside the
front or back of the envelope even inside the gross weight limits and
absolutely so if outside the gross weight limit.

In the Coupe’s case, the designers thought that the original 415-C deserved
to carry 1400 pounds.  But, the FAA was being very, very careful writing
regulations for this unprecedented two control, certificated as spin proof
aircraft.  I think you’ll find that the primary difference in gross weight
is regulatory, not aerodynamic or structural.

As for taking your sons for a ride:
  160 yourself
  250 son
  915 aircraft
 ====
1325 empty weight less fuel

    75 pounds fuel / 6 = 12.5 gallons

12.5 gallons – 6 gallons reserve = 6.5 gallons or 72 minutes at 5.4 gph.
(For putting around, maneuvers, pattern work my actual burn was about 4.5
gph but I planned local flights based on 5.4 gph, my 2400 rpm cruise fuel
burn.)

So, if you’ve got a 415-D (or later), you can certainly take them for an
1-hour long flight.

If you have a 415-C or 415-CD, you’re right, your sons can’t go for a ride
till they lose weight or you decide to bust the gross weight limits.

Ed


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