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Today a group of us were doing F3B speed run practise for
the upcoming F3B International Event in South Australia. One of the guys has a
new Carbon Nyx (F3B). I told him about the recent posts on RCSE and due to
the comments about the carbon version, we thought everything was OK.
No it wasn't.
Even the carbon version hori. stab pushrod has a
weakness. The day was fairly windy so most of us were using experimenting with
full ballast including the Nyx. After a few uneventful but fast runs, he
launched into big air, went to zoom and the thing dived straight for the ground.
Luckily he was able to recover it with fistfuls of up. On the ground we noticed
the "neutral position" was now a down input.
What happened? The clevis out of the backend of the
carbon push/pull rod was bent at 45deg. This explained the sudden down
input.
How did it happen? This rear area of the pushrod is
unsupported. Closer inspection revealed that the previous landing must
have been a little hard (It really didn't look it). The
rear moulding (under the rudder) had some cracks and there was a bit of fin
post separation, but the shock must have put a slight bend in the unsupported
pushrod/clevis as well and the compression loads during the huge launch
bent it good.
What to do about it? I have a Nyx on order and love the look
of it, it does fly fast and tracks well and I guess you can expect a few
teething problems. I still want one but when I get it, I will reinforce the
light weight moulding under the rudder. I'll install some kind of support around
the elev pushrod near the aft clevis (it has none!) and reinforce the base of the fin post attachment to the fin skins. Can
one of you dealer guys pass this info on to the manufacturer?
We were giving all our models a fairly hard time
launch wise due to the conditions. One guy's Stratos fluttered loudly on
the zoom, due to poor control he got it on the ground asap but gently and
we found the wing, from tip to tip, had damage with the centre panel
trashed, even the fuslage had damage. All that from a second of
flutter.
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- [RCSE] NYX- Something to check Mike Reynell
- Brian Ford
