Minus Thermic

With depth of detail and presentation I think you missed your vocation Mike.you should have been a school teacher not a driving instructor. very informative thread.Almost makes me want to build one !

simondean wrote: With depth of detail and presentation I think you missed your vocation Mike.you should have been a school teacher not a driving instructor. very informative thread.Almost makes me want to build one !

The trouble with being a teacher is you have to work all evening preparing for the next day...wait, what time is it now!!!

Okay, I don't normally swear on these forums, but fup me, this thing is fupping minute, and it takes fupping ages trying to fit everything inside. If they'd made it even just one fupping millimeter bigger all round it would have been easy.

The wings are designed to be removable, yet the aileron pushrod is fixed at both ends with heatshrink. So if you want to remove the wing you will have to remove the heatshrink and replace it every time. So I made up some bespoke aileron quicklink-cum-pushrods from the wire and carbon provided. Actually, I used slightly thicker wire because the stuff provided is too small for my servo arms and would have resulted in too much slop. Hopefully the images will explain themselves. The red thread is kevlar and the whole shazam is cyanoed when you're happy

After removing a small triangle from the rear of the fuselage last night to allow the elevators free movement, I found another problem,,,when applying up elevator the pushrods will foul each other limiting your up elevator throw. A solution would be to use very short elevator horns, but I had already cut them to 8mm and decided that even shorter would not be acceptable because:
1. Shorter horns would give limited 'grip' for the heatshrink and
2. Shorter horns would result in MORE elevator movement than needed and I would have to dial down the throw using travel limits, and this would reduce my resolution

So the elevators were removed and a couple of mm cut from the ends in order to increase the gap. With hindsight, only 1mm was needed

The plan shows quite long servo arms for the elevators, but again this would result in too much elevator throw, so I cut very short servo arms and drilled 0.6mm holes for the pushrods to fit via an L-bend. This will give me removable elevator servos if I strip a gear instead of using the heatshrink method as shown on the plan.
At the back end I tried many times to get the heatshrink to fit and eventually solved the problem using a simple balsa 'jig' to hold the wire in place while the heatshink was shrunk. Using soft balsa, I was able to remove the jig afterwards by destroying it. 'Magnum' splints are used to hold the elevator level while the tube is shrunk
BTW, I use a small soldering iron to do the shrinking. You can touch the shrink tube with the iron on all sides until it is tight and the heat is localised enough that is does not affect your covering

MikeSeale wrote: Okay, I don't normally swear on these forums, but fup me, this thing is fupping minute, and it takes fupping ages trying to fit everything inside. If they'd made it even just one fupping millimeter bigger all round it would have been easy.

Unfortunate my glue will be arriving tomorrow, the postage was £1 so I was expecting it to be put it in a Jiffy bag with a 1st class stamp to arrive on Saturday, oh no, it's coming with full tracking via DPD! Who don't deliver on Saturdays.

Anyway, I'm really looking forward to starting my build now, I seemed to struggle with getting stuff into my cavernous interiors of my Atlas and Mythos, so this is going to be interesting. I'm glad Mike is having such fun because he bought two of the little beauties, the second is the Acro version :evil:

Maiden flight s completed successfully. A few short throws across Cashmoor allowed me to make small trim changes, but it was virtually trimmed anyway - thankfully. Then off to one of the Wessex slopes where I had half a dozen flights, each time adjusting the CG rearwards until it felt right. The slope and the wind were not the best, but the Minus flew well. It gained height quickly when the lift was good and scooted along well. When the lift dropped or when I was ham-fisted it loses the height quickly too...get it wrong and you're going to a long walk!!! On a good slope with a slightly stronger breeze it will be a lot of fun. The only issue I had was that one of my elevator servos is slower than the other. I noticed this while setting the throws this morning so was expecting it to skew out of a look, which it did. I'll swap the slow servo with the aileron servo to see if this gives a better match.

Glad it went well Mike

Shouldn't be long until mine goes for its maiden flight, I suspect it will need a few more clicks of trim than yours did

As it is a really small model I went with bright colours to give myself half a chance of seeing it!!

You could finish covering the Impressivo while you're at it Chris