Highside Glider

[Jeffrey Cottrell 2]

Hi Guys

Sorry to be a pain, but I'm having some issues with my Highside build, and I could use some help. I am using the SLEC cnc cut pack, which is pretty good quality overall.

So, to horse.

The wing is pretty much done. Just the sheeting to add, but I wonder if someone might have a picture of the rear centre section, where the wing bolt fits.
SLEC give two ply plates, spaced to fit between the rib extensions W1A, with 6mm holes in the middle. These are obviously designed to be laminated together and glued to the rib extensions. What is not clear is whether these plates are glued flush with the upper edge or the lower edge of W1A's.
I would guess flush with the upper edge. If they are glued to the lower edge that only leaves one glue joint holding the wing on. Not really in keeping with the strong build of the rest of the structure.
Anyway, some confirmation would be useful.

Main thing, though, is the fuselage, namely formers 2, 3 and 3A.

The instructions call for a strip of 6mm x 6mm to be glued in flush with the lower edge of the cockpit opening. Although not mentioned in Lindsay's build log, the plan also shows a strip of something glued under the wing seat.
SLEC include a mystery length of 6mm x 3mm in their pack, and I assume that goes in here.
Former 2 includes a notch for this. However former 3a has two notches at the bottom, spaced to go over the under wing strips, but the notches are 6mm x 6mm. Also has nothing where it goes over the under canopy strip. Easy enough the cut notches for this, if that's what's intended.
F3 is the real puzzle, in that it can be fitted two different ways.
This former has two 6mm x 6mm notches on one end. Going by the lettering on the plan, the former is designed to be fitted with these notches at the top, but I see no mention of any secondary longerons at the top, only on the bottom.
Fitting it this way up, there are two 6m x 3mm notches which line up with the underwing strip, but again nothing where it goes over the 6mm x 6mm under canopy strip.
In fact there could not be notches here. Where the centre of the former has been cut out, that leaves the edges only 6mm wide, so having notches here would cut the former into two halves.
Fitting it the other way up, gives the 6mm x 6mm notches at the bottom. I understand that the lower secondary longerons terminate at F3, not through it, no big issue, and the 6mm x 3mm notches fit exactly where the under canopy goes, but again 6mm x 3mm, not 6mm x 6mm.
Guess I could do some sort of a 'halving' joint in the longeron, (knew my 'O' level woodwork would come in useful) but would this sacrifice too much strength?

Sorry to go on at such length, but this is my first purpose built slope soarer, and I know they need to be more robust than flat field, to withstand the rough and tumble involved.
Far rather ask the questions first, rather than guess at a solution.

Thanks

Jeff

[Lindsay Todd]

Hi Jeff, its been a few years since i designed this one but will try my best and of course the prototype was not from the slec cnc kit, that came later however will try my best to help, although any other builders please chip in.

it might be easier if you can post some photos to help identify issues you are having identifying the way forward.

From memory the rear wing ply plate sits flush with the underside of the wing and then has balsa block infill, then the second ply plate on top before sheeting such that the wing bolt does not crush into the surface. I sometimes wish they did not pre cut the six mm clearance hole as it makes alignment so much more critical that just drilling through later straight through and into the captive nut plate below. he photo below shows the infill which is sitting on top of the first ply plate.

6 mm x3mm strip is glued flush to the wing seat internal faces for added strength to the wing seat area as cab be seen in photo below

regarding F3, the only photo i have is the prototype however the cnc version should have 6mm square cut outs to clear the top longerons yet to be glued here on the right hand side identified by the black line

i hope that helps a bit for you. Linds

[Jeffrey Cottrell 2]

Hi Lindsay

Thanks for your help, much appreciated.
Also apologies for my previous post being a bit 'wordy'. They say a picture paints a thousand words. I decided to go with the thousand word option and ended up reading like War and Peace.

So I have added a picture, hope this helps

The formers in the picture match those on the plan, and orientated the same way. F2 has two notches, one 6 x 6 and the other 6 x 3. These line up with the strips at the canopy join and also below the wing seat. All good.
Former F3 has 6 x 6 notches at the top, as does F3A, which would seem to indicate that there are secondary longerons fitted to the top of the fuz, same as the bottom.
Not mentioned in the build instructions, would these be a later addition?
Also, F3 has 6 x 3 notches just below centre, which line up with the underwing strips.
What concerns me most is that neither F3 or F3A have notches to go over the 6 x 6 strips along the canopy edge.
In fact F3 could not accomodate these strips, since the edges are only 6mm wide, so would mean cutting the former in half.
Appreciate the 6 x 6 canopy strip need to be full length to add strength where the canopy join is, so that's staying as is. Question is what do I do with the formers where they go over this strip?

Looking at the picture you posted of F3, you note that the cnc version would have 6 x 6 cut outs for the top secondary longerons. Yet another indication that these are fitted to the top of the fuz, not just the bottom. Could you confirm?
Main thing is, maybe the camera angle, but the under canopy strip looks like 6 x 3 not 6 x 6. This would be a problem if I deepened those notches to accomodate 6 x 6. As can be seen, that would cut right through the former edges and leave it in two halves.

So, that's the issues. All can be fixed but I'd rather talk to you first, see if I'm reading this right.

BTW, thanks for the picture of the wing bolt fixing. Much clearer idea now of how that goes.

Cheers

Jeff

[Lindsay Todd]

Jeff, F3 sits behind the wing cut out so is not cut in half, F3a is the rear former to the canopy section so logerons are a but joint hence no cut outs see photo below

hope that helps

Lindsay

[Jeffrey Cottrell 2]

Hi Lindsay

Thanks, that helps a lot. Think it solves the mystery of F3A at least.
As your picture shows, F3a extends from the top of the cockpit longerons up to the top of the fuz. Measuring off the plan this should make it about 54mm high, about the same as the rear cabin former C3.
That's what's fooling me. The F3a supplied by SLEC is acually 89mm high.
I assumed that F3a extended below the cabin longerons and engaged with the underwing longerons.
The outline of the formers supplied matches those on the plan, so I guess an error must have crept in when they re-drew the plan for inclusion in the magazine.
No biggy, just have to cut F3a down to size.
Still leaves a question about F3.
The notches as supplied by SLEC are only 6 x 3. The width of the edge of F3 at this point is only 6mm wide, so if I deepen those notches to accomodate the wider longerons, that would effectively cut the former in half.

This should illustrate what I mean

I'm tempted to cut through the longeron to half its depth, forming a halving joint, but would this detract too much from the strength in this area?
Finally, on that same photo, your text says the cnc version will have 6 x 6 cut outs to 'clear the top longerons yet to be glued'.
Can you confirm for sure whether there should be internal secondary longerons fitted at the top of the fuz, same as at the bottom?

With your help, I'm slowly getting there.

Cheers

Jeff

[Lindsay Todd]

Jeff, i believe you have F3 upside down, the 6mm square cut out locates on the lower longeron which runs from this former forward to F1, the 6x3 cut out is for the below wing seat 6x3 doubler. The top of F3 should have no cut outs as the sides are flush and sheeting over the top. Lindsat

[Jeffrey Cottrell 2]

Hi Lindsay

I still think we are talking at cross purposes. I have added some more pictures to illustrate this.

On my original post I did mention that F3 could be fitted two different ways.

Pic 1

This shows a dry fit of F3 with the notch engaging in the underwing doubler. On the plan the position of this former, and the lettering indicate this is the correct way of fitting it.
However, please notice the cut outs are now at the top, not the bottom where they should be.

Pic 2

This is the same view, except F2 is now fitted as well. The notches line up pretty well here too.

Pic 3

This shows the under canopy 6 x 6 in place. F2 has notches to accomodate this, but there is nothing on F3 where it goes over this doubler

Pic 4

This is a close up of this area, showing the question I am posing.

Seems to me that either I am missing something blindingly obvious, or there's more than one mistake when the plans were re-drawn.

With your help and patience, perhaps I can find out which.

Thanks

Jeff

P.S. In his build log on Slope Soaring Sussex, Paul did mention some issues with the formers, but no detail as to what. Not sure if he's still active on this forum, but I might try to get in touch with him another way, see if his issues parallel mine.

J

[Lindsay Todd]

ok Jeff, not a problem it seems there might be an issue with F3 although it seems we can work around it quite easily

it looks like the 6mm square cut outs are on the wrong end and should be on the base of the former. Don't panic we can either cut 6mm notches in the end as these need to clear the lower edge longeron that needs to be glued to the lower inside edge of the fuselage or trim the longeron either side of the former as it will not impact strength unduly.

Like wise with the top 6mm cut outs either and a short length of 6mm square to the top of the fuselage sides on the inside face such that they locate, only a short length would be necessary 25mm or so simply so we utilise the structure of simply glue some 3mm hard balsa and trim to square up the former, either option will be fine.

The logeron above the wing chord does not extend past Former F3 simply buts against it as far as i recall as is cut away to form part of the wing structure top section and adds no effective strength behind the former and can be safely removed

Linds

[Jeffrey Cottrell 2]

Hi Lindsay

This might be a 'Eureka' moment
First of all, no issues with notches being in the wrong place. They can be filled in or re-purposed easy enough.
No big deal.

The canopy doubler, however is a different matter.

In your log, you specified that the canopy doubler extends to the edge of the fuz sheeting. I assumed this to mean that this doubler needed to be in one continuous run for strength purposes.
I know there is a discontinuity where the over wing section is cut away, but what wasn't clear was this doubler could also break either side of F3.
Said I was missing something obvious, didn't I.
Anyway, I was looking for ways for F3 to fit over the doubler, rather than between it.
In fact, if I read your latest post correctly, the section of doubler from the back of F3 to the end of the sheeting can be dispensed with altogether.
Looked at this way, everything else becomes much clearer.
So, time to stop talking and get on with some building.
Thanks again for your help. In the nicest possible way I hope not to have to call on your expertise again.

Cheers

Jeff