Cincinnati, OH
- Aircraft Year
- 1998
- Aircraft Type
- 114TC/115TC
- Reg Number
- N114AD
- Serial Number
- 20020
Re: Long Trip ended with a bit of excitement
Believe it is a function of speed req'd to move the fluid into the low pressure side of the cylinder. It is drawn in, so no air, but the fluid is not under presurre. If you note Figure 3.2 in the hydraulics section, you will note the dump valve returns the fluid to the reservoir through Port "D" (quite rapidly as you will note) fluid can be drawn back into into through Port "C" but the pump isn't directing the flow and fluid can be building up inside the reservoir faster than it will flow back through the manifold/check valve system w/o the aid of the pump. The vent is a convenient path of least resistance purge point but only to the degree necessary to temporarily accommodate the excess fluid. Eventually the reservoir fluid reaches a level where the dump doesn't overwhelm the reservoirs capacity when allowing for the bypass flow into the low pressure side of the system.
Again, isn't an issue if the reservoir isn't completely full and may vary a bit depending upon pump/manifold/check valve/etc. condition. The reservoir will still carry sufficient fluid to operate the system when it reaches the "accommodating" level. When overhauling my pump last year, I had the "opportunity" to experiment with the system and observed this condition.
Believe it is a function of speed req'd to move the fluid into the low pressure side of the cylinder. It is drawn in, so no air, but the fluid is not under presurre. If you note Figure 3.2 in the hydraulics section, you will note the dump valve returns the fluid to the reservoir through Port "D" (quite rapidly as you will note) fluid can be drawn back into into through Port "C" but the pump isn't directing the flow and fluid can be building up inside the reservoir faster than it will flow back through the manifold/check valve system w/o the aid of the pump. The vent is a convenient path of least resistance purge point but only to the degree necessary to temporarily accommodate the excess fluid. Eventually the reservoir fluid reaches a level where the dump doesn't overwhelm the reservoirs capacity when allowing for the bypass flow into the low pressure side of the system.
Again, isn't an issue if the reservoir isn't completely full and may vary a bit depending upon pump/manifold/check valve/etc. condition. The reservoir will still carry sufficient fluid to operate the system when it reaches the "accommodating" level. When overhauling my pump last year, I had the "opportunity" to experiment with the system and observed this condition.
