This article was written according to aircraft standards but the principles of Chains remain the same but if applying the knowledge to low power chains on Bicycles, Then you can make your own risk economic based reduced standards. If working on aircraft, always refer to the Maintenance manual.

The purpose of chains is to transfer power from one sprocket to another transfer kinetic(motion) energy. To accomplish this task you need at least an assembly of chain(s)(manufactured to SBAC standards like BS228:1994 or ISO606-1982), sprockets(toothed wheels) and possibly other accessories like interplaner blocks for changing the direction of the chains.

We will start with the main unit called the chain. This is an assembly of:-

  • outer plates
  • inner plates
  • Rollers
  • Bearing pins
  • Bushes

The pitch of the chain is taken from centre of one roller to the next one i.e. the distance between the bearing pins.


Chains riveted links are not allowed to be broken down and re-riveted and only accepted from an approved manufacturer, with the correct packaging and transportation precautions taken.

It is permitted that a bolted joint may be disassembled and re-assembled, but, it is worth while noting these next few points.

1) SBAC states that all nut and bolted chain assemblies must be peened with the exception of the 8mm variety which must be split pinned

2) All nuts used on the chains must be locknuts(this nut is normally part of the outer plate)

3) All attachments must be either riveted or bolted

4) SBAC have standardised four sizes of chains by pitch size


British Standards have laid down the proof load as one third of the minimum breaking load (mbl)

5) Continuous(endless) chains must consist of an even amount of gaps between rollers(pitches)

6) The following table is the four classifications of chains and their statistics.

PITCH — MBL(lbs) — PROOF LOAD(lbs) — BS
8mm ——— 800 ————- 267 ——————— 1
0.375″ ——- 1900 ———— 634 ——————— 2
0.5″ ———– 1800 ———— 600 ——————— 4
0.5″ ———– 3500 ———— 1166 ——————- 6

7) A non-reversible chain is a chain that may only fit a certain way round which can be achieved by correct unsymmetrical positioning by the outer plates fitted to the chain.

8) Irreversibility can be achieved by

  • Non-reversible chains
  • Non-interchangeable end fittings
  • Correct positioning of sprockets
  • Guards and shrouds

9) When storing a chain it must be well soaked in the approved oil, laid flat on its side on top of greaseproof paper and coiled firmly (not tight but not too loose).


This unit is used as a high strength power transfer device. When inspecting the chain make sure to check the proceedure in the maintenance manual which should at minimum account for the Following

  • Wear on the sprocket ( See spec in aircraft manual)
  • Wear on the rollers ( See spec. in aircraft manual)
  • Twisting (This is cause for rejection)
  • Stiffness ( This can be determined by drawing the chain around the fingers on your hand or maybe a substitute of the same sort of shape and texture [ You do not want to damage the chain by scraping the links on an object used in inspection] and checking for smooth articulation of the links. If stiffness is detected, the chain may first be cleaned and re-checked but if this is not a solution, the rollers may be lightly TAPPED preferably with a small pin hammer. if this does not fix it the chain is the scrapped.
  • Deformities, Cracks or corrosion ( These is cause for rejection)
  • Overheating (Bluing)
  • Elongation (Maximum of 2%)( To check for this the chain must be cleaned and dried with compressed air. Lay the chain flat and straight and apply a tensile load/ force [see table below]. Now measure the distance between all the pin centres and apply the following formula:

Percentage of Elongation (Method 1)

Length Of Chain with Force applied x (No. Of Pitches x Pitch measurement)
No. Of Pitches x Pitch Measurement

Note: All measurements are in inches

Tensile load required on Chain (Size is British Standard)
Size – Load (lbs)
1 —- 12
2 —- 16
4 —- 28
6 —- 28

Percentage of Elongation (Method 2)

Measured Length
——————————— x100
Original Length

Gravitational Energy Recovery System (GERS)

Time for a concept that can solve the energy crisis for infrastructure power systems. When reading this, please be open minded to see the fundamentals at work and open your mind to the possibilities if we use alternative fluids.

You can download the full report with workings at the bottom of this post.

The Gravitational Energy Recovery System (here on referenced to as GERS) answers the question of how we produce renewable power for Static power systems to further secure energy resources for consumption.

There has been much research into this field of recovering gravitational energy, some more famous than others but have always looked at a direct approach, much like climbing a hill in a car without changing gear. These methods of recovering the energy are flawed in principle much like some of my early work but now I have achieved a positive output which can be readily developed further and enhanced with further development – not of the mechanical system but fluid components. The mechanical system has already had 2 potential configurations through concept development but the simplest is used here.

In this paper I have used electricity as the output medium to be distributed but it is possible to also be a purely mechanical output.

The Theoretical model discussed has a daily (24hours) output of 0.292.6224 KWh with water (SG1) but the practical has an output of 1.1705 KWh per day from 1.2 cubic meters of fluid at Specific Gravity of 4. To put this in perspective, 1.2 Cubic meters is 1200 litres, to put in perspective, if you are 5 feet tall, then about a third of your height, again in length and depth. This gives the scalability of the solution especialy if containment of toxic fluids, like Mercury (Specific Gravity of 13), is possible.

Toxic Fluids – Why?

  • Don’t forget this is about stationary power production and no matter how Toxic a Fluid is, it can be controlled and recycled, which in my mind is better than Nuclear or other Gas Pollutants.
  • It is important to note the link between Specific Gravity and power output as we can research into heavier low viscosity fluids but may have to accept that to be commercialy viable, we may need to adopt less favourable materials.

So How Does It Work?

GERS is a very simplistic system and works in much the same way an internal combustion engine works but rather than having a negative overall Energy balance, GERS delivers more output than input of kinetic energy by recovering the gravitational effect on the fluid with the following Components:-

  • Pump
  • Pistons
  • Chambers
  • Rotating valve plates (system illustrated uses magnet control but could be more directly coupled)
  • Pipework
  • Output Shaft
  • Electrical Generator or Load Control Unit (if purely mechanical)
  • Control System

In simple terms you have a first chamber with a piston inside (much like a shock strut). The Piston has orifices much like a shock absorber but also has a rotating disc on top with corresponding holes and magnets on its perimeter. This cylinder has fluid pumped to the top of the cylinder where the fluid is in freefall onto the top of the piston. This piston is driven down by the weight of the fluid. Once the piston reaches full travel at the bottom of the chamber, the valve plate (on top of the piston) is rotated by the repulsion force of the magnets on the valve plate to the magnets on the outside of the chamber. Once the valve plate is opened, the Fluid will pass through the orifices in the piston allowing the Piston to receive an upthrust based on the principle of buoyancy of Materials of different total specific gravity i.e. wood naturally floats on water. This upthrust will reset the piston position at the top of the chamber ready to be driven again. While the Piston is driven to the top, the valve plate is rotated to the closed position using magnets on the outside of the chamber. The piston may be mechanically locked in position operated by a control circuit.

If we have a 1m tall column of water and we just return that water via a pump, then the theory is that the energy loop will always be deficit the efficiency of the pump. So we will not do this yet. What we will do is let gravity empty this cylinder into an identical but shorter cylinder and Piston system till this fluid has levelled at half its original height.

So far we have recovered energy from 1 full drive down from the first cylinder (Value of 1) and have recovered quarter again from the shorter second cylinder (0.5 of fluid x 0.5 of distance)

We now Have 2 columns of water at 0.5m and can split them again (2 x 0.25m)

We now have 4 columns of water at 0.125m tall which can be split again (4 x 0.125m)

For my theory example I have stopped here deliberately as I only wanted to prove the positive energy output but in the real world application the amount of cylinders is limited only by the value of the energy recovered by the cost of the extra components.

The actual mechanical operation for a 4 cylinder 4 stage system would be as follows. (Please see method below drawing)

  1. Water is pumped from the pump to the top of Cylinder C1
  2. Once the piston P1 has moved full travel, the valve orifice plate is rotated and opened allowing the piston to return to the top of the cylinder.
  3. Valve V1 is now opened allowing Cylinder C2 to be filled and Piston P2 to be driven down to full travel.
  4. Now valve V1 is closed and V2 opened to fill Cylinder C3.
  5. Piston P2 valve orifice plate is now opened and the cylinder is returned to thetop of the cylinder where the valve plate is rotated closed.
  6. Once Piston P3 is at full travel, Valve V2 is closed and Valve V3 is opened to fill cylinder C4.
  7. Now piston P3 valve orifice plate is opened to allow the piston to return to thetop where it is closed again.
  8. Once Cylinder C4 is filled and Piston P4 has reached its full travel, The piston Valve orifice plate is opened to allow the piston to return to the top. Valve V3 is also closed.
  9. The fluid is now pumped out of the bottom of cylinder 4 via drain D3 to the top of cylinder 1.
  10. After a delay but before all the fluid has been pumped out of cylinder 4, Valve V6 is opened to drain Cylinder C3 to Cylinder C4 to repeat the Piston P4 cycle. The valve V6 is closed again after the Cylinder C4 has been filled.
  11. The Drain D2 on Cylinder C3 is connected to the Pump and fluid returned to the top of cylinder C1 while the Cylinder C4 Piston P4 is returning to the top of the cylinder.
  12. Now Valve V4 is opened to fill Cylinder C3 and cycle Piston P3 again.
  13. Step 9 is repeated
  14. Once cylinder C3 is filled, Valve V4 is closed and V5 is opened to fill cylinder C4.
  15. Once cylinder C4 is filled Valve V5 is closed and the drain D1 on Cylinder C2 is connected to the pump to return the remaining fluid back to the top of cylinder C1.
  16. Step 9 is repeated.
  17. Step 10 is repeated.
  18. Step 11 is repeated
  19. Step 9 is repeated.

By now you should be able to see how it works but please download the whole report below.