P. Ponk FAA/PMA Approved, STC'd
Landing Gear Beef Up Kit
for Cessna models 170, 180, 185, L-19

The P. Ponk Landing Gear Beef-Up Kit is an FAA Certified (STC #: SA2918NM) gearbox modification for Cessna models 170, 180, 185 and L-19. The purpose of the Beef-Up Kit is to reduce the probability of landing gear failure during a groundloop or gear strike and to minimize the damage that will occur.

 P. Ponk Part Number:
PSK1101

$250.00 Plus freight

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Note: Drill Bits are not included in the kit, they are sold separately.

 Click here to see how it works
 
  • Double gear box shear load strength.
  • Triple gear box side load strength.
  • Significantly reduce the potential for gear box failure.
  • Reduce groundloop damage

 
  
 Don't let this happen to your airplane!
 

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Why is the Beef-Up Kit necessary?
The stock landing gear box on Cessna 170, 180, 185 and L-19 works very well as long as the aircraft travels in a relatively straight line during takeoff and landing and it is not subjected to any type of shear load. However, when a groundloop occurs, the side loading on the landing gear increases the tension load on the landing gear attach nut and bolt beyond design limits. The landing gear leg and gear box is essentially taking the load in the opposite direction from it's intended design. Rather than the majority of the load being carried by the lower angle bracket and inboard bulkhead as a shear load, the load is transfered as a tension load to the single main landing gear attach nut and bolt which hold the gear leg on the aircraft. Often times this load is enough to simply strip the nut off the end of the bolt which frees the gear leg and allows it to fold under the aircraft. If the wheel or gear leg hits something like a large rock, a log, a chuck hole, etc. the gear leg can easily exert enough shearing force to simply cut or tear the main landing gear attach bolt in half, see photo below.

The nut was stripped off this bolt when the load was transfered from
shear to tension during a
groundloop. Note flat threads.

  
During this groundloop the main gear bolt failed and the left gear leg was torn completely out of the Aircraft.
This main gear bolt was literally sheared in half when the wheel hit a large hole at approximately 40mph.
 

 

How does the Beef-Up Kit work?

The Beef-Up Kit consists of two precision milled aluminum blocks (one each side) which are bolted to the side of the inboard landing gear bulkhead, directly over the gear leg attachment hole. The block is held in place with six 1/4" dia. bolts. To hold the gear leg in place a 4" long attach bolt is installed through the Beef-Up block, the gear leg and the lower angle bracket. When the gear is subjected to the side loading that occurs during a groundloop, the majority of the load is now transferred to the main gear bulkhead via the Beef-Up Block and the six attach bolts. Without the Beef-Up Kit the entire load is taken by the main gear attach bolt and nut under a tension load. A condition which it was not designed to be subjected to.

With the Beef-Up Kit installed the shear strength of the main gear attach bolt is doubled and the side loading strength is tripled .
 

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What happens to the aircraft when the landing gear bolt fails?
 

 
  
   
 How long does it take to install the Beef-Up Kit?

Installation is accomplished through inspection access holes using standard shop tools. Approximate installation time is 3 to 4 shop hours.

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