Adhere To The Manufacturer’s Specifications For Trouble-Free Service

For decades, GSC propellers have been used on tractor and pusher aircraft, gyrocopters, airboats, powered parachutes, and powered paragliders. They provide excellent thrust and performance, and when installed correctly will continue to prove themselves as the best propellers on the market today.

As with any specialized equipment, installation as well as care and use, must closely adhere to the manufacturer’s specifications. This will result in many hours of trouble-free service.

May 17, 1999 – GSC Systems Service Bulletin

Affected Models: All GSC Systems 2 and 3 made ground adjustable GSC Systems has been in the business of producing quality propellers for over 30 years, for many types of aircrafts. Over the course of these 30 years, it is possible that the original aircraft and/or the GSC propeller may have changed ownership several times. During the transfer of ownership often the instructional and maintenance procedures of our propellers have been lost. To that end, many propellers receive incorrect maintenance. The most critical assembly procedure of our propellers are that the hub and root ends not be tighten past the recommended 100 in/lb torque specification. It is also possible that due to the over tightening of the attach bolts, that the space between the aluminum hub halves is not longer visible. The result of this improper assembly or maintenance could result in premature blade failure resulting in either injury or death. If you do not presently have a set of GSC assembly instructions, please contact GSC Systems and one will be forwarded to you. Required Service: Immediate Inspection
  1. Inspect to insure that a visible gap between the aluminum hub halves is detected. If no gap is visible, contact GSC Systems.
  2. If you are the initial and original owner of a GSC Propeller, are you certain that the hub has never been torqued past the 100 in/lb MAX specifications, if not please contact GSC Systems
  3. If you are not the original owner of a GSC Propeller, can you be assured that the GSC Propeller hub has never been torqued past the 100 in/lb MAX specification? If not, please contact GSC Systems
GSC Systems TBO GSC Systems have documented user times over 1000 hours but due to the nature of the exchange and selling of our product we are implementing a 500 or 5 year TBO for all GSC propellers. If you require further information, please feel free to contact GSC Systems. Our goal is to continue the supply of a quality and safe product.

Questions And Answers

If you have a brand new propeller, there is no balancing necessary. All propellers are final balanced at the factory. If, however, you have altered your prop in any way, then balancing may be necessary. Propellers must be balanced using a proper balancing method, not simply by weight.
The multi-blade propeller is easily assembled on a flat working area (following assembly instructions). All bolts are finger-tight only at this time. The propeller can then be mounted on the prop flange on the aircraft, and pitch can be set while on the aircraft using the GSC Pitch Adjusting Tool.

Complete assembly and use instructions are provided with each tool. The downloadable Pitch Setting diagrams and instructions on this page will help you in setting pitch using GSC Pitch Adjusting Tool.

All bolts, when using the GSC blades with black composite root ends, are to be torqued no more than 100 in/lbs. or 8.5 ft/lbs. Blades with aluminum root ends can be torqued more.

Yes, you should check the tracking of all blades while they are installed on the aircraft. The tolerance of the blade tracking is 1/8″ at the tip. Blade tracking can be manipulated slightly by applying forward or aft pressure on the appropriate blade while torquing bolts.

Yes, the propeller hubs are designed to have a 30 thousandths gap when the round root end of the blades are placed inside. Do not over-torque bolts until the gap disappears. Torque to a maximum of 100 in/l

There should always be a slight gap. This design is to give a clamping action to the blades and not allow them to change pitch in flight. Our experience has shown that a lack of gap is usually the result of over-torquing.

Yes, we can replace just the one blade. However, if the propeller is more than two years old, the new blade may not balance with the old blades and it will be necessary to return the old blades and have us balance the new blade to them.

Double-check your tracking (tolerance of 1/8″ at tip). Double-check the pitch of your prop (variance from blade-to-blade should not be more than ½ degree). If propeller has been altered in any way, balancing may be necessary. If vibration still persists, it could be from another source, such as engine crankcase or gearbox issue.  Simply call GSC Systems for advice.

The numbers are reference balance numbers which GSC uses in their balancing method. They should be quoted when ordering replacement blades. It is important that in a set of blades for a particular prop, these numbers all be the same.

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We’re proud of our team, and we believe in having long-term employees and trusted customer service, all to the benefit of the thousands of satisfied customers.

Excellent products, unbeatable customer service, combined with very competitive prices makes GSC Systems still one of the greatest propeller manufacturers in the industry today.