WHO'S BUILDING WHAT FOR 2021

[Nigel Ellis-Gray]

Hi Cliff
I was aware that they did stock these but the overall cost is £35 with the shipping to France. For this reason I started looking for another solution. A 14mm carbon tube & steel rod costs the equivalent of £18 here. Obviously this has its attractions but I don’t want to risk the model by using the wrong approach or one of insufficient strength. The killer on the cost is the shipping to France.

Thanks for your input though.

[Johan1969]

Hi,

I am new to this site. I will start building Chris Williams Bergfalke IV this year. I bought the plans and the short kit last year.
I recently started with the hobby again. (I have been away for 33 years)
I know I will need some support from you guys. And as we don’t have a lot of slopes in Belgium, I would like to E-Bergificate my Bergfalke to.
So Chris, your guidance will be more than welcome.

As this is also my first ever “short kit” build, I will have some challenges ahead.

Johan

[Dale Nichols]

Regarding the high shipping cost of the joiner material, you can ask Gliders UK to cut the material in half (ie to the size thats generally needed) and this will save you some money on the freight. Living in Australia we have the same problem if you want to use that joiner system.
Failing that you change the design and use carbon or aluminium as an alternative.

[chris williams]

No problemo, Johan...

[mjcp]

There's a *LOT* of control inputs going on in that pic!

~40 degrees bank angle, cross controls (?) AIL/RUD, up ELE, Brakes out (and power /ON?)

... and all in proximity to the ground (could be the lens I guess making it look closer)

[chris williams]

Johan, have you received all the build pics for the Bergfalke from me...?

[Arthur Fielding]

Re wing joiner material
Some time ago I built my first 1/4 scale glider ,and not knowing any better i used 1/8 x 1/2 mild steel for the wing brace ,cos i had some ,fitted vertically I felt sure it would be strong enough. We watched in horror when on being released from the toe the wings slowly clapped hands ,and the model spiralled in. the 1/8 x 1/2 had bent a full 45 deg
A friend of mine flies a large,expensive all glass glider ,the wing joiner as supplied with the kit was a stainless bar 1.25 in diameter ,following an impressive low level wiz followed by a loop he calls landing as he has a problem, he got it down safely .The G force had bent the stainless bay, it seemed impossible.
I have come to the concluion that theres a lot more going on in them there wings than meets the eye ,so with due respect unless you have a degree in
aeronautics I would recommend that you stick to the recommended materials. It will be cheaper in the long run, as a years worth of work only takes seconds to hit the floor.
Good luck ,stay safe
Arthur.

[Noël Rumers]

Gromotec in Germany sell glass fiber rods in a few dia.
Petrausch sells the fenolyth tubing for them.
I just ordered for a friend a 16 mm glass rod for his 4.4 m span glider.
One could use also the hardened steel rods that are used for linear bearings.
They come with weight too but are the only steel shafts that can be used my thinking...
From 20 mm on you can buy them hollow as well.
Sizes are 5 - 8 - 12 - 16 - 20 - 25 - 30 - 40 - 50 - 60 - 80.
Hollow they come from 20x14 - 25x15.4 - 30x18 - 40x27 - 50x28 - 60x34 - 80x56<ID.
Gromotec sells glass fiber once from 2 - 4 - 6 - 8 - 10 - 12 - 16 - 18 - 20 - 25.
Petrausch sells the tubing from 10 mm ID.
He also sells Strongal ALu tubes, but these are not fit for gliders!!! His own saying to me!!!
I do hope this helps!
Noël

[B Sharp]

Noel, I am fiberglass rod averse having used it for wing joiners on thermal soarers in the past. My first experience was when one let go while winching on a breezy day. There was a mighty bang followed by a one winged model returning to earth. When the wreckage was examined the glass joiner had exploded but the fibres had not let go. They had formed something like two paint brushes joined together at the ends of the bristles. The second occasion was on a clumsy landing where one joiner let go. This time the fibres had expanded to more than double the original rod diameter and proved impossible to remove from the wing or the fuselage!
Brian.

[Nigel Ellis-Gray]

My query about wing joining materials has brought forth several different views. Mild steel will bent, fibreglass rod/tubes can fracture or disintegrate and carbon can suffer structural failure at the wing/fuselage interface especially in the case of a hard landing.

That leaves us with the original material, brass box/steel blade. This solution goes back years. I’m not suggesting it isn’t good but surely it is not the only solution for long wings of larger heavier gliders given the advances in material science.

I may well have to stick to brass box/steel blade and swallow the cost but I’d like to investigate the alternatives first.