KF2 fuselage geometry

[skelly 12]

Hi everyone,

I have done a search on here but couldn't find an answer so I thought I'd post my question here and see how I go.

While looking at my KF2 fuselage I decided to measure and check everything.

One thing I noticed is that the LH rear spar attachment point does not aim exactly at the centre of the LH lift strut bolt.

The right one lines up perfectly.

I double checked with a long straight round 5/16 bar pushed through the little tubes on the ends of the rear carry through tube and the LH one likes to aim just half a holes worth forward of the lift strut bolt hole where the RH one easilly lines up dead centre.

So..

Does this mean I have a problem ?

Will this mean that the LH lift strut will be exposed to bending/ stress due to the point that the wing pivots back is not exactly in line with the point that the lift strut pivots back ?

Or am I worrying about nothing ?

I'm quite prepared to remove all 4 little tubes (one is shagged anyhow) and make new ones, put them in a square jig and weld them in, but if I do weld them in are they exactly vertical as std ?

Cheers.

Skelly.

 

[1avidflyer 1983]

I would certainly think the rear spar bolt hole, and the bottom lift strut attachment should be in line.  It is a hinge after all when you fold the wings.  If the wings never folded, it probably wouldn't matter at all.  JImChuk

[flywise 169]

Hi everyone,

I have done a search on here but couldn't find an answer so I thought I'd post my question here and see how I go.

While looking at my KF2 fuselage I decided to measure and check everything.

One thing I noticed is that the LH rear spar attachment point does not aim exactly at the centre of the LH lift strut bolt.

The right one lines up perfectly.

I double checked with a long straight round 5/16 bar pushed through the little tubes on the ends of the rear carry through tube and the LH one likes to aim just half a holes worth forward of the lift strut bolt hole where the RH one easilly lines up dead centre.

So..

Does this mean I have a problem ?

Will this mean that the LH lift strut will be exposed to bending/ stress due to the point that the wing pivots back is not exactly in line with the point that the lift strut pivots back ?

Or am I worrying about nothing ?

I'm quite prepared to remove all 4 little tubes (one is shagged anyhow) and make new ones, put them in a square jig and weld them in, but if I do weld them in are they exactly vertical as std ?

Cheers.

Skelly.

 

This might be due to the LH wing incidence you can adjust on the LH strut. Once adjusted, the wing may be under some tension and the holes don't line up perfectly....

You can try to install the wing/strut with the lower bolt and only one upper bolt and then adjust the adjustable eye bolt to line up with the remaining bolt hole.

Hope this makes sense, Laurent

[1avidflyer 1983]

Not meaning to sound offensive Laurent, but one of us misunderstood the question.  You have me wondering if it was me.   I understood him to mean that if the wing is off, and he ran a straight rod down through the rear wing spar attachment point on the fuselage, it didn't line up with the lift strut attachment hole at the bottom of the fuselage.  I've been wrong before though, so it won't be a new experience for me.   :-)   JImChuk

[skelly 12]

Not meaning to sound offensive Laurent, but one of us misunderstood the question.  You have me wondering if it was me.   I understood him to mean that if the wing is off, and he ran a straight rod down through the rear wing spar attachment point on the fuselage, it didn't line up with the lift strut attachment hole at the bottom of the fuselage.  I've been wrong before though, so it won't be a new experience for me.   :-)   JImChuk

Jim you are spot on,

I have remeasured,

with the RH pin tube absolutely vertical the LH pin tube is angled back slightly, hence why it aims towards the front of the lift strut bottom bolt.

Weird.

[1avidflyer 1983]

Maybe there is enough slop in the holes so that it doesn't bind when the wings are folded, but for sure it shouldn't bind.  That would be trying to twist the carry though tube or pull on the bolt holes in the spar, or both.  JImChuk

[flywise 169]

Not meaning to sound offensive Laurent, but one of us misunderstood the question.  You have me wondering if it was me.   I understood him to mean that if the wing is off, and he ran a straight rod down through the rear wing spar attachment point on the fuselage, it didn't line up with the lift strut attachment hole at the bottom of the fuselage.  I've been wrong before though, so it won't be a new experience for me.   :-)   JImChuk

Hey good catch Jim....should have drunk a second coffee this morning HaHaHa

[Avid90 12]

Maybe heat the fuselage's left hand pin tube support and twist the pin tube so it lines up.  Then weld in a bracket like they do in Europe to reinforce the rear spar attachment.

Edited 16 Dec 2020 by Avid90
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