1994, ah, a very good vintage. Fortunately, I upconverted all my WordStar
files to Word sometime back. I don't have the drawing referred to in my
computer files. But, if you want the drawing, you'll probably want the
engineering report, too, and will contact the engineering company (details
at the way bottom).
Here's the article referred to in the swap page post on shoulder harnesses:
Melvin C. Shaffer
4301 Vauxhall Road
Richmond, Virginia 23234
My friend Cliff spent 11 years building a Polywagon. Truly a
labor of
love. The first flight went off without a disaster but the second was quite
different.
About 200 feet in the air and a few hundred yards from the
runway end the engine quit. Impossible to get back to the field and nowhere
to go but down. The landing was into the trees, the plane fell through the
branches and landed upside down on the woodland floor. Crushed, wings torn
off but the cabin and bubble canopy reasonably intact. But Cliff had on a
good set of lap and shoulder harnesses. No fuselage fuel tank - no fire.
And, in spite of some injuries, he walked to the nearest house to call for
help.
His wife and 6 month old daughter and his friends visited him regularly in
the Hospital and he convinced a lot of us that a shoulder harness was a good
thing.
I began a search of the literature, of Skip Carden's 337 file and read part
43.146 - 166 "Acceptable Methods, Techniques and Practices". I consulted
my FAA friends and together we arrived at a couple of basic points to
consider: There is no suitable frame member in the Coupe to attach a
shoulder harness fitting to. Aft of the pilot, the Coupe is primarily skin
with a few frames and pieces to hold the skin in place.
The logical conclusion then was that a shoulder harness had to be attached
to the skin.
Shoulder strap positioning is clearly laid out in part 43. To comply with
its provisions leaves only one place to attach the strap flange, this being
frame F and the aircraft skin before and aft of it.
Several others have arrived at this same conclusion and I hereby credit them
all with participation in this end result. My only contribution is to
combine the best features of all those made available to me through Skip and
to lay a basis for each person to present his project to the FAA for
approval.
There are a number of good approved seat belt, should strap combinations
available from the standard suppliers. Mine uses the Y shoulder harness
wherein both straps come together a few inches aft of the pilot's shoulders
and attach to a single fixture. A simple metal cleat holds the lap and
shoulder straps together.
The drawings are self explanatory. The fixtures are simple to make and
install. They serve to give a good perch on frame "F" and a good rivet
pattern into the skin aft of frame "F" with the strap attach bolt also
securing the unit to the skin ahead of Frame "F".
To print both sides of the 337 seems a waste of space in the Capers. Here is
the essential language from the 337 description. The front simply contains
the standard field approval stamp signature:
INSTALLED SHOULDER HARNESS ATTACH FITTINGS IN ACCORDANCE WITH DRAWINGS BY
M.C. SHAFFER DATED 2-14-94 FOR FORNEY F1A AIRCRAFT, REG. NO. N3055G AND
AC43.13-1 & 2 AS REVISED.
THIS INSTALLATION IS AN IMPROVED MODIFICATION OF THE INSTALLATION ON N99762,
ERCOUPE 415D, APPROVED NW-GADO-5 ON 5-1-81.
THE FOUR ATTACH FITTINGS WERE MADE FROM .063 2024T3 ALUMINUM SHEET FORMED TO
MATCH THE AIRCRAFT SKIN JUST AFT OF FRAME F AND 5" FROM STIFFENER ASSEMBLY
#41, P/N 415-3116L&R. A SLOT WAS CUT THROUGH FRAME F MEASURING .13 X 1.25"
TO ALLOW PASSAGE OF THE FITTING FOR ATTACHMENT TO THE SHOULDER HARNESS STRAP
ATTACH PLATE. A 3/4" X 3" .063" 2024T3 ALUMINUM ANGLE WAS RIVETED TO THE AFT
SIDE OF FRAME "F" AND TO THE FITTINGS AND SKIN USING A TOTAL OF 16
MS20470AD4 (OR EQUIVALENT) RIVETS PER ASSEMBLY.
WEIGHT AND BALANCE WAS COMPUTED AND ENTERED IN APPROPRIATE AIRCRAFT RECORDS.
While it is impossible to test the G loading capability of these straps
without destroying parts of the aircraft, a reasonable mathematical
assumption can be arrived at by using shear strengths of the attaching parts
and tear strengths of the sheet metals involved. Others have applied several
hundred pounds of pull to similar attach fittings with no evidence of
buckling or tearing. The fittings presented here are modestly stronger and
more securely attached than the test unit.
No claim can be made that these fittings will sustain the 20g loading
recommended in part 43 but it is the opinion of all who have studied the
project that they meet or exceed the strength of those used in all popular
training aircraft currently in use.
_____
From: ercoupe-tech@yahoogroups.com [mailto:[EMAIL PROTECTED] On
Behalf Of [EMAIL PROTECTED]
Sent: Wednesday, January 02, 2008 7:18 PM
To: [EMAIL PROTECTED]
Cc: ercoupe-tech@yahoogroups.com; [EMAIL PROTECTED]
Subject: Re: [ercoupe-flyin] RE: [ercoupe-tech] Re: Shoulder Harness STC
For those interested in shoulder harness, I found this on the swap page.
I made a shoulder harness installation on my 415C, N2486H patterned after
the one in the Aug.1994 issue of Coupe Capers and submitted my FAA Form 337
with complete documentation. After about a year my last (and possibly best)
information from the OKC FAA was to have an FAA Designated Structures
Engineer fill out and sign an FAA Form 8110-3. Just under $1000.00 and 28
pages later I had an approved shoulder harness installation in N2486H. I
have started the process of getting an STC and PMA for the bracket in order
to get some of the money back that my company spent but this may take years,
if ever. In the mean time, if any of our Ercoupe owners are interested, I
will supply a complete set of my company's engineering drawings and an
approved and signed FAA Form 8110-3 (all 28 pages) along with a letter from
my company authorizing instalation on one specific aircraft for the price of
$100.00. If this information was submitted along with a properly filled FAA
Form 337 it should get prompt field approval. If not, return the material to
me and I will refund the $100.00 Floyd Culp AIRCRAFT & INDUSTRIAL SERVICES,
INC. N2486H 918-341-5735
Floyd Culp < <mailto:[EMAIL PROTECTED]> [EMAIL PROTECTED]>
Claremore, Ok USA - Saturday, February
Lee
-- "Ralph Finch" <[EMAIL PROTECTED]> wrote:
[Both groups 'cause there's Tech and Flying news]
Try reaching David at <mailto:[EMAIL PROTECTED]> david AT smoler.name
replacing AT with @. Whether he wants to sell the plans anymore I don't
know.
I bought David's Alon and his original shoulder harness. It's fairly good,
though because it doesn't have a crotch strap it tends to loosen and ride up
over time. A quick check and tug to tighten it before landing corrects
that.
Fortunately it was tight last night (12/31) when I made a sight-seeing
excursion over the Golden Gate Bridge and headed south along the coast to
Half Moon Bay. There was a strong north wind at altitude (above 500 feet)
but relatively calm on the surface, at least in the west side of the
Sacramento Valley where I left. Who knows what it was doing in the Bay
Area, but just south of the little chunk of 1500' Class B airspace on the
coast opposite SFO, I hit some of the worst turbulence I've ever had. More
than once only my seat belt kept me from hitting the canopy....the VSI was
pegged down. I wasn't too high so that worried me. OK, I admit, I was
scared! Sweaty palms and almost worse! I can't swim and there were no boat
lights on the ocean. I did a 180 turn and headed back to calmer air, only
the second time I've done that in a plane. Worked too.
A few minutes later, listening to NorCal Approach, they issued a weather
advisory of severe turbulence below 6000' in the Bay Area. No kidding!
Fly safe--
Ralph Finch
Davis, California
_____
From: ercoupe-tech@yahoogroups.com [mailto:[EMAIL PROTECTED] On
Behalf Of [EMAIL PROTECTED]
Sent: Tuesday, January 01, 2008 6:36 PM
To: [EMAIL PROTECTED]; ercoupe-tech@yahoogroups.com
Subject: Re: [ercoupe-tech] Re: Shoulder Harness STC
Mark,
I've lost track of David Smoler's address. I think that he moved quite a
while ago. Maybe someone on the list has some contact info for him?
You might also try looking in the tech archives and see if you find anything
there. If not, let me know and I'll try to find his old address and we can
go from there.
Best Regards,
Wayne DelRossi
Alon N5618F
Hours logged since restoration: 347.5
.
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