Moses Bolt Torque?

[airsail]

It’s the nature of a taper fit, they settle over time with use and require a retorque. The taper moves ever so slightly into the corresponding hole and the screw looses torque. Most of the pressure is on the front of the fuselage as the wing is pushing upwards and your weight downwards hence the front screw loosening.
This is a common problem with tapers, but the advantage is a very strong stiff joint. I work in aviation and we use tapers to mount the rotors on a helicopter. These require a retorque several flying hours after install as the taper settles. We can retorque the joint sometime 5 times in 50 flying hours.
The ultimate fix would be a stainless torx bit, that could be carried to give the joint a retorque during the session.

[Peter_Frank]

Interesting, how many degree taper?

Sideways and at the ends that is.

Let's say 90 degree sides is 0 degree taper.

Will measure mine tomorrow, but I only got one center screw.
The KFBox has 3 degrees at the board connection, in both directions, but I don't know how the mast-fuselage is.

Peter

[grigorib]

I believe Moses is 15 degrees angle

[airsail]

The mast doesn’t touch the bottom of the socket in the fuselage, maybe a 2mm gap between the two. It’s a good system as over time things wear, but the mast will move slightly further in maintaining a solid connection.
This is unlike Armstrong, where any wear will cause slop because the assembly screws aren’t pulling the joint tighter.

[Peter_Frank]

The mast doesn’t touch the bottom of the socket in the fuselage, maybe a 2mm gap between the two. It’s a good system as over time things wear, but the mast will move slightly further in maintaining a solid connection.
This is unlike Armstrong, where any wear will cause slop because the assembly screws aren’t pulling the joint tighter.

Thanks airsail

Now we know why it becomes loose, the taper combined with a gap under the socket.

My advice, without having had the Moses, would be:

Clean the parts with water before assembling, if possible.
Put the board on its back on the ground, and wiggle the fuselage on the mast, and tighten both bolts again, a few times.

Tightening harder is no good, can actually destroy threads, and wont help one bit.
It might still be necessay to re-tighten after the first session of course.


Above is what some do naturally, others dont.
Some might rig on grass with no sand, thus cleaner.
Some might keep the mast/fuselage connected for a long time, thus they wont experience the issue much.

It is the downside having a gap under a tapered fit, but the good thing is does not become wiggly over long time use and wear.
A more spot on fit without gap and with less taper, does not have the "screw becoming looser" issue, but it has other issues, more costly to make precisely, and might get loose and wiggle when worn, and require a "touch up" later.
Having an even wider tape angle will make the load on the screw and inserts a lot higher, so there is also a max angle you dont wanna go to.

Nothing is better than the other IMO, just different ways, with each their own advantages/disadvantages.

Nice to know exactly what the cause is now

Peter

[Foil]

It’s the nature of a taper fit, they settle over time with use and require a retorque. The taper moves ever so slightly into the corresponding hole and the screw looses torque. Most of the pressure is on the front of the fuselage as the wing is pushing upwards and your weight downwards hence the front screw loosening.
This is a common problem with tapers, but the advantage is a very strong stiff joint. I work in aviation and we use tapers to mount the rotors on a helicopter. These require a retorque several flying hours after install as the taper settles. We can retorque the joint sometime 5 times in 50 flying hours.
The ultimate fix would be a stainless torx bit, that could be carried to give the joint a retorque during the session.

So good to know, thanks
So for long term care for the many like me who take the fuse off every session, then being very careful after and BEFORE every session is so important to the life span of the taper fit quality, I for one wash after each session with tap water (both mating surfaces, I always carry bottles of tap water in the car)
Neoprene sock or other cover over the mast end for protection from sand and knocks, then before assembly clean both surfaces again, there is always tiny bits of sand stuck inside the fuse taper slot, right around the edges, and finally nip up the bolts with care and if possible give a final firm push or rocking pressure on top of the wings and final nip up on the bolts, 2 finger 1 thumb seems to work best for me, ( but for me using a lube on the bolts is a will not do, the fact it just turns into grinding paste very quickly is a problem I prefer to avoid, and getting grease on my fingers will transfer to other parts and that will cause problems of its own)

[Wazza Foil]

I can not believe there is so much torque on this topic.

[pākihiroa]

I can not believe there is so much torque on this topic.

Apparently, on this thread, people are seizing the opportunity to strip away the confusion on this gripping topic.

[grigorib]

It’s too much tension

[pākihiroa]

It’s too much tension

True that. Suggest we bolt to the nearest exit before the nut cases start posting.