Overview
With the latches installed the movement to starboard of the canopy frame created by the gas cylinder had to be corrected.
It was found that if the the cylinder was removed all the gaps and alignment with the front cowl were correct, confirming that the cylinder was the cause of the alignment issues.
With the cylinder reinstalled and canopy closed it all moved to starboard but if the frame was pushed just past the front hinge a substantial correction occurred. After a lot of thought it was realized that the cylinder now hinged the canopy frame at the rear with all the clearances appearing at the front hinge.
What was needed was a means to counter the 14 kg of side thrust. While lifting the canopy up and down and considering options it was realized that the inside face of the canopy was close to the roll cage - had a ridged mount.
Installation
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| Test wheel and longer locating pin |
Note: The battery drill slow speed allowed the drill bits ends to survive the pressure required.
An old rubber caster wheel was wrapped in tape, fitted and the canopy lowered - joy of joy every thing was back in alignment on the port side and at the front and rear. There was still a issue at the front hinge but it was felt the installation of the locating pins would address that issue.
A new longer brass pin was installed at the center and with the nose of the hook dressed the canopy closed one handed but inspection at the front and rear showed that the gap between the front cowl had opened up and the rear closed.
What caused this ?
Numerous adjustments and test showed that the canopy would open and close while picking up the center pin but the front and rear pins were out just slightly. At this point the center pin was removed and everything returned to normal, it was realized that the canopy was being push out of shape by the center pin.
The most likely cause was the new spreader / cylinder attachment with gussets added to control the torque created by the cylinder attachment. Where the original spreader had no ability to affect the frame shape the the new rigid spreader did and locked it in. When these were added no relationship to the locating pin was taken into account, this explained why all points were just out - a new shape had been created.
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| Spreader & Gussets |
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| Button length determination and rear button installed |
The height was measured and a new buttons were machined and fitted, this process was repeated at the rear leaving about a total of 1.5 mm gap between the front and rear buttons.
The front buttons ensure that the frame squares up as its closed with the latches operation re-checked before moving onto the next task.
The final task was to refit the pins but to reuse the original locating holes required a new mounting point for the center pin. A piece of 25 x 3 aluminium is was fixed in location to the longeron using thin double sided tape then the location of the pin marked using the same technique used originally.
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| Revised attachment |
The aluminium was anodized then fixed using M4 x 12 hex head screws with the pin fixed using an M4 counter-sunk screw, refitted, tested with the same technique to be used at the front and rear.
Comment
Why all these issues - probably an operator error - no excuses offered.
Next job is to install the correct wheel and guide cam but right now it works well in fact until the rear hinge was added it could be closed by just pressing down on the canopy with the front hook opening and closing the mechanism on the way down but with both hooks in it closes easily with a reassuring solid thunk after a firm push on the handle..!
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| Canopy in the 50% open position and balanced Nearly there..! |
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