Belly pan fastening

The belly pan needs to be fastened firmly so that it doesn't fall off. It must not rattle either.
It would be nice to be able to fix it without tools or bolts that might fall off because of vibration.

The best functioning system I have seen so far is Ola Fremming's spring system. That is not very aestetical, though.
I designed a new system with same functionality as Ola's system but I hid it inside.
When my Sombrero's belly pan is fastened by this system with two springs and six dowels it is so strong that I can lift the the plane 
holding the belly pan only. The springs pull the the belly pan towards the fuselage to prevent rattling. The springs are fool proof,
they do not come loose inadvertedly. It is also not possible to stretch them too much, because the bolt restricts movement.

Click to see a larger picture There are two 3 mm steel dowels behind the wing. Belly pan has 3.5 mm holes where the dowels fit.
Both fuselage and belly pan has 4 mm plywood doublers to support fixing points.
See also pipe tunnel extension to enable use of Bolly EQ 140 N pipe. Also Greve pipe would fit.
Pipe tunnel extension has 5x5 mm balsa collar and it glued in place with epoxy-micro-balloon mixture. 
Click to see a larger picture See the fastening spring inside the fuselage. Spring is made of 1 mm piano wire and with 13 mm stroke
it creates appr. 20 N force. The spring is attached to a plywood plate with a screw that is secured wuth CA.
Note also the Sullivan pushrod going to throttle. This type of pushrod dampen vibration and is recommended
with mini servos instead of rigid steel or CF pushrod. Especially important with soft engine mounts.
Click to see a larger picture Part of spring outside. The slot is necessary because the spring is flipped in lock position, see below.
There is also a pair of dowels in front of the fixed landing gear.
Click to see a larger picture .See the slot in belly pan. It is very easy to lock/unlock the latch with a finger movement.
Click to see a larger picture Front dowels of 2 mm steel.
Click to see a larger picture .Another view of front dowels.