The flying monkeys got me...

Helis and fixed wing

AMA 957918
IRCHA 4345
AMA Intro Pilot Instructor

Pirate Kid Skeleton by RadDezigns.

Tuesday, May 5, 2020

MX-Bach Tune Up

The MX-Bach was acting the fool last time I took her out to the field. All of my planes lately have had issues with idles that need to run high, and she was no exception. I have decreased the amount of oil to a bit thinner than 1:40, which I hope will help, and make for a lot less oil thrown on the fuse and wings. 

I noticed on inspection that the muffler has come off the cylinder. The Pulse XT 40 did this as well, seriously affecting how it ran, and its issues resolved with fixing it.. I will need to make this a regular preflight check. I think it is likely one of the reasons I had idle issues. Before I start screwing around with the needles I will start her tomorrow and see if this solves the issues.


One screw holding it on, oil sprayed all over the place, took a bit to clean up, and I couldn't get all the oil stain off the muffler.



Made a new gasket, or I should say, made a gasket because there wasn't one. Liberal Locktite.



The silencer had fallen off on the bench at the field, fortunately not in flight as it would be history. Whew... It popped out of the silicone having lost the securing wire tie. I used two this time.


Last time I took the MX-Bach up she was having idle issues. I had to bring her in hot, and she was floaty, after several attempts I finally brought her in and a foot off the ground killed the ignition. The same hand is used for the kill switch that I have on the elevator, soooo... I accidentally gave a little up elevator, she lifted up and stalled, dropped, and broke off an end of the CF landing gear. Thank goodness I have an exact replacement brand new hanging around in my shop! Some minor internal damage, mostly just cracked spars, easily fixed.



Took no time to drill the new holes and install. New pair of pants!



Messy during Man Working Time!



I installed a new tail wheel bracket because the carbon fiber one was getting too soft and wobbly. I purchased one for 120-150cc sized aircraft because, I don't know why. I should have gone with the smaller one, but I think I went with this one because the hardpoint on the fuse is shorter. I could have just cut the other one. It really doesn't matter, this one works fine. I wanted a metal one that would hold the vertical axle firmly, and this does the job. Since it's off center from the hinge point I thought of and tried a couple of different connections for the turn coupler, and ended up just using the rod method. To keep the turns from being too acute I had to put the rod connector pretty far aft. It works fine.


You can see the hardpoint on the right just fits on the tail of the fuselage. The tail wheel is now much more secure and sturdy. 

This is the kit that arrived. I know what each piece is for, but I don't understand that the silver handle screwed into the blue aluminum piece is. I removed the handle and used the blue part as the rod connector to the tail, as can be seen in the photo above this one, on the left. I was able to put an M2 bolt through it into the wood, so that is what I used it for. If anyone has any idea what that this is really for I am curious. Of course there were no directions/instructions...

I am now cleaning up the prop's paint a bit, and will reattach it tomorrow after re-balancing it and then see what I need to do to get the idle set right.




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