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Stephen,
By always routing these
questions and answers through the list, we can often share the info with
lurkers and get corrections when we slip so I’ll cc this to the list. Please just respond to the list and I’ll
get any questions just as fast AND other (often more knowledgeable people) can
also help. I surely don’t know it
all (even though I often use declarative sentences) and I appreciate the
additions and corrections of others (or how can I someday know it all????).
I’ll try to give you an
organized picture (as I understand it):
1. Gross weight – no exceptions
reference: http://ercoupe.org/Coupe_models_table.htm
a. Any 415-C or 415-CD may
carry up to 1260 lb.
b. Any 415-D, E G or
Forney F1 may carry up to 1400 lb.
c. Any Forney F-1A, or
any Alon or Mooney M-10 may carry up to 1450 lb.
2. Elevators
a. A 415-C must have 13° of up travel
b. A 415-D must have 9° of up travel This ain’t so bad – that’s what I had and it worked just fine
– your touchdown speed raises by about 5 mph – no big deal. Additionally, the extra limit on the
elevator keeps you from having the slipstream push down the tail so far that,
with the increased gross weight, you get into a stall that is too aggressive
and might let you spin.
c. All models from 415-E onward have the
split elevator and 20° of up travel.
The main difference in this is the cutout in the elevator to let the
slipstream pass with little effect on elevator trim. This gives the plane little trim change from full power to
idle. If you trim it for 75 mph at
cruise, it’ll stay close to that at full power and at idle. With the slipstream NOT pushing down on
the tail, having extra power is no problem because the slipstream can’t push
the tail down – so you can’t get into too aggressive a stall (or spin).
3. Engine
Check the paperwork of
the airplane – the form 337. These
(when signed by the FAA) are the legal documents for the plane’s modifications –
often called “one time STC”. If
the FAA signed off on a change, it’s legal.
I’ve only heard of the
crank-changing engine upgrade in a couple of casual discussions in recent
years. Apparently someone had this
good idea and got someone to approve of it. It sounds like a good idea. If you have a form 337 approving that engine change, it’s
legal.
4. Model changes
a. You MAY NOT carry more than 1260 lb. as
long as the plane is a C model.
b. You must convert it to a D to carry
1400 lb. The specifics to do this
are authorized by the aircraft type certificate. Follow the type certificate’s requirements and the change is
legal. Aircraft Specification
A-787 governs all models except the C.
c. According to the FAA type certificate
person I talked to, it’s not *possible*
to convert a plane from one model to another unless that change is specified in
the type certificate. In this case
A-787. A change from an earlier
model to an E is not possible, I was told.
http://edburkhead.com/Ercoupe/index.htm
(scroll down to the bottom
of the links)
d. However, you can change it to BE a
415-D and have the legal 1400 lb. gross weight then submit a form 337 to change
the elevator to the split elevator to be “like” an 415-E. (All the change to be “like” an E gets
you is the 5 mph slower touchdown speed and less trim change when you change
power.)
5. My recommendations:
a. Change it to be a 415-D. This gets you the legal 1400 lb. gross
weight. If the work is already
done, you don’t need Skyport’s STC.
Your mechanic just needs to certify all the changes and write them in
the logbook and write up appropriate form 337s. There’s debate on whether you need to apply for a new
airworthiness certificate. Some
do. Some don’t.
b. If you can glom onto a split elevator
at a good price, write up a form 337 and get it processed through the FAA and
approved BEFORE mounting the elevator on the plane. Some idiot FAA wienies have turned down this mod due to
ignorance and inability to think.
This mod ONLY returns the plane to the original designed landing speed
while preventing excessively high angle of attack (and risk of an unpleasant
stall) at very high power settings.
This is a desirable change, but I never judged it to be worth a thousand
bucks. For a few hundred, I would
have made the change.
When you write up the
form 337 for the split elevator, be sure to emphasize that 1192 planes were
manufactured with the split elevator and flew at the same or higher gross
weights and with similar power plants.
The split elevator was specifically designed to maintain the good behavior
for which the plane was certificated at those weights and power.
Ed
Burkhead
http://edburkhead.com/
ed -at- edburkheadQQQ.com (change -at- and remove the
QQQ)
From Stephen:
Ed,
Spent some time with the airplane, asking some
more specific questions.
It's placarded (if that's a word) as a C
model. The engine is 0-200 in a C85 case, I've found where there
are STC's to do this, so that you retain the same motor mounts, etc. No
problem with the engine, the problem comes in with typical FAA crap.
There is no STC on record to go from a C model to 0-200. You have to
first be a D. Well, I don't want the 9deg elevator, so I'd have to do
split tail, and get to an E (are you as lost as I am???).
I THINK I can have a C85 STC'd 0-200, and a C
model brought up to an E (giving me 1400lb gross, and a 12deg elevator, but
have NO IDEA how to start. Any clue?
On one hand, the worst case is I fly an 0-200 C
model, KNOWING that it's really good to 1400#, but it's uninsured if I fly it
over 1200#. At $17k purchase price, I'm not concerned with the
insurance. BUT the engineer in me wants everything to be "by the
numbers". Any clue where can I go to find the process to make the C
model into an E with a C85 to 0-200 conversion?
I THINK I would:
1. Buy the STC to go from C to D,
restricting the elevator to 9 degrees, and requiring the stainless
fuselage section. Add the stainless fuselage section. At this point,
I only have 1200# gross.
2. Buy Skyport's STC to put an 0-200 in a
D model (the work is already done).
3. Buy the STC to go from D to E, (I'm not
sure who holds this one) requiring the split elevator, but going to 13 degree
elevator, and upgrading to 1400# gross.
Is this right?
I could be reading / understanding this
completely incorrectly. What the airplane currently is = a C model with a
C75 converted to an 0-200 during a complete overhaul, by changing the crank,
carb jets, etc. I just want to find the best way to make it "legal",
and find out what that would cost.
OR could I go "Like Model D" redo the
cowling, buy the Skyport 0-200 STC, and then go "like model E", and have
the elevator modified?
Any ideas?
Stephen.
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