Republic Seabee Revision History

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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.

   

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Updated: 2013-10-05

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