In this month’s edition:

• Down on the Farm 73 last month 1/25 – Tony Palmer
• Anyone fancy building one of these? – Historic film of an unusual aircraft.
• Every Day is a School Day – Richard Griffiths
• Crazy Germans Jumping out of Gliders – Entertaining video of people doing something that, personally I’d rather not…

Down on the farm 73 last month 1/25

Klemm L25C G-ACXE

The first permit renewal is due now. As it has only flown a few hours since it has been built we expect some things to be not perfect so we are going over it more thoroughly than say a mass produced standard plane. We have jacked up the plane checked the tyres, bearing etc and readjusted the brakes

Prentice G-APPL VR189

No movement

Bristell G-NGBB and DH82C

Both planes had to have their permits renewed this month and I am afraid to say that last year I had done all of the work and Phil had inspected them but I had forgotten to send in the renewal form and money, hence all flights last year were illegal. Please check your documents are valid before you fly.

Being old and wrinkly does not help!! The new system last year did not help!!

Next club night FEBRUARY 5^th 2025

The January meeting was cancelled due to snow, so this will be our first meeting.

The club subscriptions will stay at £25 this year as it just covered the Xmas meal cost and will hopefully cover next years prices.

Please, PLEASE can we have club members come up with things to do this year!!! Maybe organise trips out to museums, fly-outs, someone to do an interesting talk??

Tony Palmer

Anyone fancy building one of these?

Every Day is a School Day

Well, I’ve learned some stuff about laser cutting. To drive the cutter I needed my design to be presented as a Scalable Vector Graphics (SVG) file. Being a bit of a cheap-skate, I didn’t fancy forking out for a propitiatory design package that I am unlikely to use again. So instead I investigated some open-source alternatives that could produce this. LibreCAD is a fully functional 2D drafting package for manufacturing and it would certainly do what I wanted, but I found the interface a bit unintuitive (and who reads the manual…). I also tried out Inkscape, an art oriented graphics package that, at a pinch could be used as it supports accurate measurements for graphical components, but it was also going to present a bit of a learning curve. In the end I copped out and turned to my ancient version of Microsoft Visio from back when you bought software rather than rented it. It is really intended for producing charts and presentational graphics, but it also supports accurate measurement – and I’ve used it loads before. However there was a ‘gotcha’ lurking in that decision.

After an awful lot of messing about and tweaking, I committed myself to a ‘final version’. I generated the SVG file and emailed it to my daughter for laser cutting. Being very conscientious and practical, she did a trial run using cheap cardboard. This is where the ‘gotcha’ appeared. While most of the required holes came out as round, quite a few appeared just as a horizontal line. A surprise! Viewing the SVG file in both Inkscape and a web browser (they also interpret SVG files) it looked fine. However the package that drives the laser cutter thought different. Daughter had to come around with her laptop so we could correct the drawings. Had I sent the file off to a commercial cutter, that could have got expensive.

I’ve now got the panel cut from beech plywood, so all I have to do is fit the components – ha! all I have to do… Every step of the way presents a challenge. My original intention was to re-use most of the components from the original panel. Connections were made by soldering, so a couple of hours fiddling with a de-soldering-iron got them off. However the key-lock switch that enables the starter and instruments circuits didn’t fare well and needs replacing.

Despite specifying the exact manufacturer and part code, my Chinese suppler managed to send something that looked the same (even had a label on with the required part number) but wasn’t; different number of connections. Do I repeat the experience and try another eBay’er? Why does it have to be a key lock switch anyway? I never remove the key from it. A rotating knob switch would do as well, so let’s find one of those.

I decided to have a careful look at the circuit to be sure my alternative would be suitable, and things got interesting. Hirth, my engine’s manufacturer, publish a circuit diagram that they label as ‘suggested wiring’. It’s pretty vague, with a number of anonymous ‘black boxes’. OK, I turn to the wiring sketch that the builder gave me – and it’s not quite the same. So I look at the wiring that was implemented, and that too is a bit different. There seems like a sensible way of wiring it that is different again. 🤦‍♀️😖 I’ll be bringing some circuit drawings along on Wednesday for your expert opinions!

Richard Griffiths

Crazy Germans Jumping out of Gliders

I got sent this on the SD-1 email list. It’s quite entertaining.

Personally I quite like staying in the aeroplane, but each to their own.

Events

Next Strut ‘Club Night’ at The Longshore is on Wednesday 5th February, 7:30 pm.

For a full list of events go to the website Events page.