Note: The final location for the pump is at the revised access hatch shown in part 4 - it improved cog and access - See comments at end of this article
Overview
The decision to relocate the hydraulic pump with the battery was a direct result of the factory supplying a spreadsheet for the weight and balance for the Tucano showing that the Tucano Rs having a particular problem created by the 7 kg of the additional weight of the supercharger.
This led to the factory supplying an engine mount shorter than a standard 912 engine mount to suit the supercharged model.
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| Estimated C.O.G. |
What does this show this builder - A Tucano is very sensitive to weight on the nose wheel, so great effort must be expended firewall forward on weight control or balance it by moving items that the aircraft requires to the most advantageous location.
The factory currently installs its 5 kg battery behind the baggage compart wall but this option was not taken as the amount of re-work required was not acceptable and in the end a 30% loss of area in the baggage compartment was considered acceptable for the style of operation contemplated for this aircraft by the builder
A battery and pump have a 5 kg combined weight matching the factory battery weight. Remember this aircraft uses LiFeO4 battery pack [1 kg] with this combination 3 kg lighter overall.
Installation
The first task was to install the battery, and this was covered in an earlier blog.
Next, the pump was removed from the factory location, the base was removed and two more feet were fabricated from 0.040'' 2024-T3 and installed. The location of the feet was marked onto the floor, M5 rivet nuts were fitted then 25 mm studs were installed into the rivet nuts with thread locker.
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| New mounting feet |
Two 50 x 6 foam isolators were installed over the studs to provide some noise isolation, but this may have to be upgraded at some time after the noise is evaluated.
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| Local wildstock Grommets and isolator pads |
Four [4] x 1/4'' id rubber grommets were fitted in the deck, providing an exit for the four lines to be run back to the original location under the co-pilot seat.
To support the four [4] lines, these are mounted using AN3 (1/4") aluminium hose separator modified to allow a M3 x 35 S/S unbrako securing the assembly to the aircraft with a M3 rivet nut.
A series of these were used to hold the lines clear the seat belt running under the passenger seat mounted on a 0.020'' x 2024-T3 folded bridge under the seat.
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| Hydraulic pump with protective cover |
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| Propellor controller is located in the pump's old location |
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| Lines from pump loose on rhs Hydraulic lines and supports will be covered in a separate blog |
Comment
Not the preferred option, but it was practical at this time mainly due to access to the skins secured in this area and will meet a goal. Doing it again, the pump would be mounted behind the baggage compartment, especially if using lightweight batteries again.
The actual hose runs came out better than they should have, as it was all done on the fly.
PS: Most of the blogs are prewritten to provide a plan of attack, and the seat belts were very difficult, especially the shoulder straps and have been redesigned numerous times, so text from previous thoughts [plans] were still left behind - fixed.
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