Philflyer

Ok. So what is a brownout?

It’s a guess. The spark interference causes servo movement that I assumed was from the receiver and it was swamping the transmitter signal. Do you have knowledge that might improve my guess? Edited By Philflyer on 03/01/2021 16:29:42

I have flown two NGH GT9s for 6 years now with considerable reliability and enjoyment. I also had the NGH 17cc that only lasted one flight due to radio failure. I thought the problem was a faulty lead connecting the Spektrum remote receiver but later through experience with the GT9s I found the most common fault was the Rcexl spark plug cap. It is easy to fit the cap badly as it is very stiff when new and loose when old. If this happens a spark occurs between the cap and the plug that causes loss of control with the DX6i, mostly at full throttle. The fault can disappear very quickly but may also cause a receiver brownout and disaster. Consequently I have been very careful when fitting the cap and always do a control check with the engine at full power as part of my pre flight checks. This morning, however, I had a rapid and intermittent elevator glitch when at full throttle in the air just after take off. I made a quick circuit and landed. For once the fault could be reproduced on the ground, only at full power, and I immediately suspected the plug cap. It was very dirty inside, old baked oil, so I cleaned and refitted it and all seemed ok. The next flight was similar however so I started packing up, to go home and investigate further. As I took the cover off the bottom of the fuselage to release the wings (a Seagull Cherokee) I noticed the Rcexl ignition unit had come loose from its velcro and one corner of the metal housing was touching the steel throttle cable. I attached the unit back in its place and tried again. Perfect! As luck would have it a few of us old and bold guys had been discussing radio problems due to metal to metal contact at the field a few days ago. I had heard of it of course and always use a nylon clevis at the carburettor but this took me by surprise. I am so glad I could reproduce the problem because had it not been found and a wreck had ensued it is extremely unlikely that the fault could have been found so probably blamed on other parts of the radio. A lesson well learned. Let’s hope the rest of 2021 continues as lucky!

That’s terrific Alex. Does the HK stuff stick okay? Do you know if it stays good? That could tempt me back from glassing and painting. Edited By Philflyer on 31/08/2019 22:32:51

Check my album “Boomerang test bed”. Ok I know. Off topic now. Done.  Edited By Philflyer on 31/08/2019 22:25:04

Totally agree with you about the Boomerang. Mine now has an ASP 91 converted to petrol. Still handles like a trainer but goes vertical forever. Had to move the firewall back 2 cms. It looks like a dog because of the covering but I will get around to that. So you think I don’t need to do anything with the Cherokee? I’m happy with that. It looks like being an even better flier than the Boomerang but the u/c needs modding to handle the crosswind landings we have to deal with here. As you probably guessed I’m a bit of a Seagull fan.

Can anyone recommend a colourless fuel proofer to use on the joins of Oracover? I have a Seagull Cherokee that is beautifully covered as supplied, and I don't want the gunk from my petrol engine to get under the edges and ruin it, like it has my Boomerang 2.