| Applicable
Serial Nos: |
Description: |
|
|
| 1 thru 4 |
Franklin 6A8-215-B7F
engine 212 hp. |
| 5 thru
125 |
Service Bulletin No: 2 -
Dated 1946-12-18
Replacement of induction system backfire screen to meet CAA
requirements.
This change involves removing the flexible tube between the hot air
shroud on the manifold and the carburetor intake duct, installing the
new backfire screen in this tube and reinstalling the assembly. |
| 5 thru
174 |
Service Bulletin No: 1 -
Dated 1946-12-18
Modification of firewall terminal block to prevent short circuiting of
terminal studs on the firewall. |
| 5 thru
487, except 480 |
Franklin 6A8-215-B8F
engine 215 hp.
Dual Eisemann magnetos ignition system.
Reverse limit 1750 RPM. |
| 5 thru
425 |
Stewart Warner type
instrument panel. Electrical oil pressure, temperature, fuel
pressure transmitters as well as electrical indicators. These indicators
have to be supplied by the aircraft electrical supply. These airplanes
also have a two magneto ignition system. |
| 200 and
up |
Redesigned main landing
gear clevis fitting. |
| 237 thru
576 |
1-1/4 inch diameter plug
button in bottom of each horizontal stabilizer to provide access for
lubrication of the trim tab gear boxes. |
| 277 and
previous |
The aft cabin skins are
subjected to stresses due to engine vibration and propeller air
buffeting which has resulted in cracking of these skins and stiffeners.
On Seabees previous to Serial No. 278, these skins were reinforced with
Z-section vertical stiffeners, which proved to be too light.
For airplanes previous to Serial No. 278, a kit is available
consisting of all necessary parts and installation instructions for the
new type hat-section stiffeners and gussets. The list price is $8.15 per
kit. (Ref: Service News No: 48) |
| 278 and
up |
The aft cabin skins are
subjected to stresses due to engine vibration and propeller air
buffeting which has resulted in cracking of these skins and stiffeners.
New hat-section stiffeners were incorporated in production on Serial No.
278 and subsequent which stiffened the skins appreciably. However, the
tie-in to the angles to the hull proved insufficient, resulting in
cracking out of the lower ends of the stiffeners as well as cracking of
the aft cabin skins just above the angles. As a result, a new
reinforcing gusset has been developed to eliminate these difficulties.
For Serial No. 278 and subsequent, a sketch provided herewith shows
the dimensions of the simple gusset which can be made up from local
stock and shows the manner of installation. Inasmuch as the hat-section
stiffeners are not joggled for these gussets which must be inserted
between the stiffeners and skins, it will be necessary to add tapered
shims immediately above the gussets in order to prevent creasing the aft
cabin skins. Each shim should be held with at least two rivets to
prevent its rotation out of place. (Ref: Service News No: 48) |
| 425 and
up |
The two lines running
down the forward side of the vertical stiffener and then forward through
the lower right hand corner of the baggage compartment wall are fuel
lines from the fuel pumps to the fuel pumps to the fuel pressure gages.
The line running down the aft side of the same vertical stiffener and
following the same route as the fuel lines is an engine oil line running
to the oil pressure gage. The two lines running fore and aft along the
bottom are hydraulic lines to the tail wheel. The remaining item is a
conduit of wires running across the lower end of the baggage compartment
wall from right to left. Check all these items for possible chafing and
excessive vibration. It is advisable to run the engine while making a
vibration check. |
| 426 thru
487, except 480 |
Two magneto ignition
system but were equipped with an Autolite instrument panel which
required no tee-in to aircraft electrical supply except for the fuel
quantity indicator and transmitter. |
| 488 and
up, including 480 |
Franklin 6A8-215-B9F
engine 215 hp.
Single Bendix magneto and Autolite coil and distributor ignition
system (split system).
Reverse limit 2500 RPM.
Autolite instrument panel. |
| 525 and up |
The link tube, which
connects the tail wheel shock absorber piston to the yoke, has been
modified by having three sets of holes provided for adjustments of the
spindle angle. |
| 577 and up |
Handholes in bottom of
each horizontal stabilizer to provide access for lubrication, repairs
and replacement of the trim tab gear boxes. |
|
|
| ENGINE
FRANKLIN "500" |
 |
| Applicable
Serial Nos: |
Description: |
| |
|
| 23001
thru 23500 |
Franklin 6A8-215-B8F
engine 215 hp.
Dual Eisemann magnetos ignition system.
Reverse limit 1750 RPM. |
| 23001
thru 23280 |
(Except those modified
to permit full reverse thrust)
Must have Hartzell Model HC-12x20-2 propeller:
7 diameter propeller cylinder with standard (4.50) counterweights.
The larger cylinder or longer, or notched counterweights, cannot be
used. This group of airplanes is restricted to 1750 RPM in reverse. |
| 23008 thru
23280 |
1750 RPM limitation in
reverse.
Small diameter propeller cylinder without counterbored holes. |
| 23281 and
up |
(Also those of Group 1
which have been modified at overhaul to permit full reverse thrust.)
(Full reverse RPM of 2500 is permitted with combinations a, d
and e only.)
(a) Model HC-12x20-2: 7 diameter cylinder with standard (4.50)
counterweights only. (Long or notched counterweights cannot be used with
7 cylinder.)
(b) Model HC-12x20-3: 10 diameter cylinder with long (4.650)
counterweights. (Engines in this group using long counterweights must be
restricted to 2300 RPM in reverse.)
(c) Model HC-12x20-3B: 10 diameter cylinder with standard (4.50)
counterweights must be converted to the 3A model by adding slugs to
these counterweights. (Reverse RPM must then be restricted to 2300.) A
Service Bulletin will be prepared by Hartzell on this item in the near
future.
(d) Model HC-12x20-3C: 10 diameter cylinder with relocated
(notched) counterweights.
(e) Model HC-12x20-3E: 10 diameter cylinder with relocated
(notched) counterweights.
The 1/8 slugs, which are to be added to 2 (c) above, can be
procured from the Hartzell Propeller Company, Piqua, Ohio at no charge.
They have offered to modify any propeller requiring slugs at their
factory free of charge. The Hartzell model numbers above have just
recently been agreed upon by CAA and Hartzell, so all propellers do not
have that identification at present |
| 23281
thru 23500 |
Inclusive Interim
fix.
1. Small diameter propeller cylinder with counterbored holes.
2. Large diameter propeller cylinder with counterbored holes. |
| 23501 and
up |
Franklin 6A8-215-B9F
engine 215 hp.
Single Bendix magneto and Autolite coil and distributor ignition
system (split system).
Reverse limit 2500 RPM. |
| 23501 and
up |
Production fix.
1. Large propeller cylinder without counterbored holes.
2. Small diameter propeller cylinder without counterbored holes. |
| |
|
