William & ED,
Thank you both very much for taking your time to reply (good info, as always).
Best regards,
Dan Hall
N3968H @ CNO
----- Original Message -----
From: William R. Bayne
To: 'ety'
Cc: Ed Burkhead
Sent: Friday, February 20, 2009 11:53 PM
Subject: Re: [ercoupe-tech] "C" to "D" conversion - landing gear
Dan,
Ed's ATC 787 source is 100% correct and authoritative information.
The full MEANING of this information is perhaps as important as the
information itself, thus:
1. For the 81+% of 415-C owners with serials 813 and over, there is NO
"required change"
to main landing gear oleos.
2. For the two-thirds of 415-C owners with serials 1622 and over, there is NO
"required change"
to the nose gear oleo.
3. Orifice changes are entirely independent of and unrelated to 1400 lb.
gross weight operations.
The latter is speculation based on the fact that orifice changes were
engineered and implemented
relatively early in 415-C production by Erco for 1260 lbs. gross operations.
Since earlier airframes
(also operating at 1260 lbs. gross weight by that time) were not "encouraged"
to adopt these
modifications we can presume NO "consequences" of substance for leaving early
oleos unmodified.
So, why did the FAA/CAA "require" changes to these earlier airframes for the
heavier gross weights?
1. The "requirement" originally brought any 415-C airframe modified to 415-D
model into proper
conformance with applicable ATC 787 specifications.
2. The 1320 lb. LSA STC was likely approved without actual flight testing by
essentially pointing
to Erco's extensive flight testing for a 140 lb. payload increase over
existing 1260 lb. gross.
Approval of a 60 lb. increase in payload for an airframe previously verified
for a 140 lb. increase
is the proverbial "no brainer". Nonetheless, it was likely deemed prudent by
all concerned to have
415-C airframes fully comply with 415-D specs. to qualify for the higher
operational gross weight
under ATC 718.
Remember, though, I'm neither engineer nor a mechanic when interpreting
information believed factual.
Regards,
William R. Bayne
.____|-(o)-|____.
(Copyright 2009)
--
On Feb 20, 2009, at 22:47, Dan Hall wrote:
Coupe technical gurus...
I have a local Couper who is asking a question that will be very easy
question for several of you.
What change was required to the landing gear, in the STC to move from "C"
to "D"?
I'm thinking it was a slight increase in the size of the orifice in the
shock damper...?
I think this should be relatively easily checked and addressed if
necessary, correct?
Just to open a really big can of worms does anyone want to speculate on the
consequences if this change was not done ?
(now taking cover behind a large hedgerow to dodge the fire...)
Dan Hall
N3968H
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