jbrown wrote:Hi Dick,
Thanks for your reply. I think there's more interest in our beloved Mirage on your side of the pond. I don't see much activity on any build threads over here, and have yet to see one (turbine powered) at any of the fields I fly at?
After seeing Harry's post on the loss of his Mirage, it's two 8711s per side for me. Sorry Harry.
Thanks to all for the answer on why no flaps, that makes perfect sense now. One less channel to use.....LOL
Let's keep this post alive for all of us Mirage addicts.
Best reqards, Jim
Not really surprised that the Mirage isn't overly popular there...I think that mainstream jet modellers there tend to stick to American prototypes...just a few seem to find interest outside!
Anyway, having spoken to Keith about the demise of his Mirage, it seems he suffered elevon flutter. Even though he had top end powerful servos fitted, he mentioned that there was some slop in the hinges of his elevons - which, incidentally, I have absolutely none on mine - and a little bit in the linkage. He surmises that, together, these may have had a contributory effect.
What also bothered Keith was the fact that the elevon detached from the model, taking the hinge pin with it - in other words, the hinge points mounted in the false trailing edge of the wing didn't have enough 'meat' on them 'behind' the hinge pin, and the pin broke loose. I believe Keith's been in contact with Fei-Bao about this last point.
Before Keith's incident, I had been thinking about splitting the elevon and putting in another servo...I was uncomfortable that there was no redundancy there...and this incident has cemented my thoughts. The issue being where to put the second servo box. I need to know what the wing internal structure's like to help make that decision and, fortunately, Keith has kept a portion of wing from his Mirage which he's letting me have so I can get a look inside. The only assumption I'll have to make is that all the Mirage wings are jig-built and, therefore, the same inside.
There is a 'scale' split point on the elevons that's just outboard of the model's horn position, so I'll probably split it there and insert a couple of closing ribs in the ends of the 2 parts.
One thing I have done with my model is to make and install 2 new elevon control horns per surface - they sandwich a ball-link - which are much longer than the kit supplied parts (surface of elevon to hole in horn = 28mm...this gives much greater mechanical advantage and much more servo movement, with the clevis at the servo end on an inner hole). I'll post details and pics of that shortly, to show how I did it. I'll also post pictures of the structure of the wing Keith's giving me, just in case anybody else wants to go the 2-servo route.