----[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]----
Ed
Burkhead
http://edburkhead.com/
ed -at- edburkheadQQQ.com (change -at- and remove the QQQ)
I know you believe you understand what you
think I said, but I am not sure if
you realize that what you heard is not what I meant. (Jim, AKA Midnight Plowboy)
-----Original Message-----
From: William R. Bayne
[mailto:[EMAIL PROTECTED]
Sent: Thursday, March 03, 2005
12:52 PM
To: Ed Burkhead
Subject: WRB Re: [COUPERS-TECH] D
and CD model history
RLYTECH (Message from Bill Bayne via Ed
Burhead's computer)
Please send responses either to the list or directly to me at
[EMAIL PROTECTED]
On Mar 3, 2005, at 7:54 PM, Hbeil wrote:
Hello
all.
My 2 cents to the model discussion.
I own 3330H, that came out of the factory
as a 415-C.
It had been factory converted to a 415-C/D
and later the 415-E conversion was approved.
The factory conversion to a C/D was one
way of Erco to improve sales in 1947. How?
ERCO tried to analyze the selling points
and payload was one of them. So they tried to get the D Model approved in the
new normal category, maxing out the new weight limitations. With 1400 lbs the
coupe would stall earlier and the elevator had to be restricted to keep the
design stall proof. It had to be that way, cause without ruder pedals, ones the
stall becomes a spin, no rescue would be possible.
(WRB talking)
Not true!
Flight characteristics even with 14º up elevator were no problem. The
problem emerged when (probably) some CAA weenie tested a 415-C and
incrementally established that at 18º up elevator the 415-C could not be made
to enter a spin, and therefore any 415-D model at 1400# had to meet that
arbitrary benchmark even though no other aircraft design had been forced to
meet such an arbitrary and meaningless standard.
The field tolerance for rigging was already established at +- one degree
without problems, so no possible justification existed for reviewing 415-D flight
characteristics at 5º in excess of that which would be approved (18º up
for 13º approved and 14º up for 9º approved).
The only reason the elevator "had to be restricted" to 9º up was
entirely arbitrary CAA requirement, which directly resulted in the undesirable
increase in landing speed and decreased ability to flare when landing. The CAA
thusly mandated a less safe aircraft for NO defensible reason, and since the
production line was already producing planes with these modifications, ERCO was
pretty much forced to offer their "new" model without the weight
increase as the 415-D but just with the cosmetic changes of the 415-CD
retaining the 1260 lb. gross just to stay in business. Efforts continued to get
the 1400# gross that resulted in the 415-E not too much later.
We
all know the story - undesirable landing speeds made the 415-D not that
marketing success as expected, so the next idea was to go back to the old TC
with a payload of 1260 lbs. This was not that simple.
Sure it was!
With
the new additions of a stainless steel fire wall extension and all the other
changes, the Coupes coming from the line were not the approved 415-Cs anymore,
they were something else.
So they called them 415-CD.
Yeah...nothing simpler than a change in name only and reducing "up"
elevator!
Whether
the Marketing for the CD had in mind that it could be registered under either
Type Certificate is not clear.
It's clear. A 415-D must conform to Aircraft Type Certificate 787. A 415-CD
must conform to Aircraft Type Certificate 718.
It
could be, because the CD Model is no different than the D Model, except for the
elevator adjustment. (S/N 4501 and up designated model 415-CD
identical to model 415-C except for revised throttle and trim control, wide
trim tab (1/3/8 in. chord)
in accordance Erco dwg. 415-22031, improved fuel venting system, revised nose
gear oleo strut,improved interior trim and installation of stainless steel
upper fuselage skin.)
Correct.
So why went ERCO out and retrofitted a
number of Ercoupes that were already in Dealers hands, but not further sold
yet? The conversion did not give you more payload or anything else that you did
not have in a 415-C. The only visible change is the throttle control. I doubt
that the airliner style throttle was such a killer feature that Ercoupe buyers
were searching for.
ERCO did this at the request of those dealers that had large unsold inventoried
of the 415-C model "obsoleted" by announcement of the "new"
415-CD. They had found that every buyer of a "new" Ercoupe wanted the
"latest" model even if the gross weight remained the same, or they
wanted a discount that would allow NO profit on their 415-C inventory. So the
factory updated these airframes in the field before sale and everyone was
happy.
My only explanation is that the 415-CD
could have been either way registered. Under both TCs.
Nope.
And that's how it should be. All Ercoupe
415s are pretty much alike.
The minor differences between the models
that justify different payloads or engines, can easily be changed on
almost any airframe.
Physically, that's entirely true. Getting the FAA to do their job and approve
changes already established as safe by others remains an unfortunately variable
challenge here in the U.S.!
That means that one type certificate would
just be enough. Most airspeeds don't change and engine/airframe changes are
minimal.
That certificate would list the model
designator and lists the necessary changes to fit into that model or category.
Example:
415-C - normal category - 1260 lb
gross, stall at 48MPH/
gross
415-C - sport pilot category - 1320 lb
gross, stall at 51MPH/ gross
(elevator restriction would have to be
reduce to 11-12 degrees up for the C, CD, and D models to stay in the power on
stall proof area)
415-CD - normal category - 1260 lb
gross, stall at 48MPH/ gross
415-CD - sport pilot category - 1320 lb
gross, stall at 51MPH/ gross
(elevator restriction would have to be
reduce to 11-12 degrees up for the C, CD, and D models to stay in the power on
stall proof area)
415-D - normal category - 1400 lb
gross, stall at 56MPH/gross
415-D - sport pilot category - 1320 lb
gross, stall at 51MPH/ gross
(elevator restriction would have to be
reduce to 11-12 degrees up for the C, CD, and D models to stay in the power on
stall proof area)
415-E - normal category - 1400 lb
gross, stall at 56MPH/ gross
415-E - sport pilot category - 1320 lb
gross, stall at 51MPH/ gross
415-G - normal category - 1400 lb
gross, stall at 56MPH/gross
415-G - sport pilot category - 1320 lb
gross, stall at 51MPH/ gross
415-F1 - normal category - 1400 lb
gross, stall at 56MPH/ gross
415-F1 - sport pilot category - 1320 lb
gross, stall at 51MPH/ gross
415-F1a - normal category - 1450 lb
gross, stall at 58MPH/ gross
415-F1a - sport pilot category -
1320 lb gross, stall at 51MPH/ gross
All models would qualify for the sport
pilot rule when operated under those limitations.
The models stay the same, just the
requirements change.
Now Hartmut, there you go again...trying to apply logic to administrative law!
But how everyone thinks these days is that
a certain model , certified under a certain category, has to stay in this category
and model designation, otherwise it is not model anymore and not airworthy.
This is the error everybody is making and
that's why we are all in pain with the tiny changes we are trying to do.
Yeah, that's the way it works here. The FAA makes the errors and the owners get
the pain.
So in my eyes , all Ercoupe 415s are
pretty much the same except for some minor details, I would not try to split
hairs over it.
Hartmut
We have no choice here but to split (and re-split) hairs if we do not wish to
risk violations from unreasonable inspectors or giving our insurance carriers
an easy way to avoid the financial responsibilities they purportedly accept in
exchange for our premiums.
In the U.S. (and under its legal system) these "split hairs" determine
whether or not a particular Ercoupe airframe is legal to operate in our new
Sport Pilot category. I agree these distinctions may be of less significance
elsewhere.
Regards,
William R. Bayne
<____|-(o)-|____>
(Copyright 2004)
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