MX-Bach Redux

The MX-Bach. Fuse of the MX2 I had busted the wing on, wings from the Sbach 342 I crashed the fuse of. MX-Bach! She has been a great flyer.

Last year I stole the electronics and servos from my MX-Bach for someone else... don't remember which plane they ended up on. I cannibalized her because I didn't fly her much. If I was going to fly a 30cc sized plane, I took the MXS-R out. Given a choice I fly gas, but my roots are in electric.

I miss her, and I need something new, so I have started purchasing replacement servos and electronics. 

I went with TACTIC TSX55 servos all around. She takes one Rudder, two Elevator, and one each on the Ailerons. These aren't digital, but I don't need that precision, they have enough torque to lift a semi, and I have had good luck with Tactic. That they are $23 a pop rocks.

I bought a Spektrum AR6010 Receiver, which allows me a channel for each servo (I learned a Mix that allows the Gear channel to run a trimmable elevator), and having dual aileron channels allows me to set up flaperons for fun and to set up differential.

She still has her massive motor, I forget which one (will update this when I get under the hood). She flies 8S-12S. I stole her Fun Fly 100A HV OPTO ESC for one of my 600 helis, so I will need to replace that. I don't think I have one sitting around, but I want to check before I shell out another $100. I have a big Turnigy 3 blade wood prop I was thinking of putting on the 30cc MXS-R, but I have been reluctant to drill the hub due to its 3 piece design with a metal plate insert. uits perfect for this plane, and this will give her massive motor some immense thrust.

I plan to power the receiver with a 2S 2300 mAh LiPO since the plane can easily handle the weight, so bought a nice switch to replace the one I took off her to fix one of my other aircraft.

So, all I need is the ESC, I think!

More to follow. Nice to have a new build!

MX-Bach flies and watching a pro

And crashing the HK EPP Sbach, again...

Beautiful day to "maiden" the MX-Bach. Calm on Mt Hudson, sunny, a bit warm, and about 4 other pilots there.

I took the Sbach up  and flew her smartly. Third pack and ( lost her is a maneuver in the sun haze, over corrected and drilled her in pulling up at the last minute. I once again knocked off the front end and turned it into powder.

After I moved her from the crash scene. I have an idea to build a firewall and install the motor on stand-offs, since I wont have a motor box. She's too sweet a flier and so otherwise intact, I can't abandon her.

UPDATE: Well, this explains things. The gears on the elevator servo are stripped... Maybe I didn't over control? Not that it matters, I had no idea what the hell was going on when she crashed. Ordered some replacement 12g Solar digital metal gear servos from Hobbypartz.

This was interesting. Yesterday I worked on gettingg the remote off switch for the OrangeRx e-axis stabilizer to work, and couldn't. Since it works otherwise fine and this twitchy beast flies well with it, i decided to fly with it on anyway. Took off and immediately things went boobies up, I had virtually no control and her tail dropped like a turd. Barely got her down with an inelegant "landing" in tall grass. I disconnected the stabilizer and put her back up, thinking there was just something wrong with the system. Again, barely got her back down. This time though I realized that last night I removed the nose down subtrim, thinking I had accidentally input it. What I had forgotten is that despite a pound of extra lead in the nose, this short fronted aircraft is tail heavy, and the subrrim lets her fly. Its easier than trying to trim it into the elevator servo. I dialed the subtrim back an and voila, she flew perfectly! Flew three more packs.

Then I fried my iCharger 208b. I had brought her put to recharge the 5S packs in the MX-bach. There is a battery based (DC) Solar Powered station there with 24V and 12V connections. I had checked and the 208b can take up to 32V DC Input. Plugged her in. Poof! Cute little puff of smoke and a soft zap. Dead. Stupid... should have just gone with the 12V, and I knew it. I think there is not a fuse inside, that the board is likely burnt, and I will be buying a new 208b. I'll open her up and check. I have had her since about 2008, so I have had a good run with her. Sad, she was one of my first major RC purchases, from ProgressiveRC. Will likely buy from them again.

UPDATE: Yeah, toast...  In the pic below you can see that one of the microprocessors is burnt and cracked. Homie is buying another one.

Burnt and cracked microprocessor.

And it says right there, 32V DC...

After that little fiasco,  it was time to fly the MX -Bach. Set her up, cal,ed my nerves, and took off. She tookmoff smartly, and flew wonderfully. Maybe its psychological, maybe its that she is a few pounds fat, but she pulled off the maneuvers like Gronkowski plays tight end for the Patiots, she seemed a bit of a lumbering lug. She felt heavy, she seemd slower, but really I think she flew as she always has. Landing with and without flaps required keeping some speed on or she sinks fast. It took a couple rough landings and I started to get the hang of getting her down. In the air I felt myself psychically holding her up in turns, tough she took them just fine. I think part of it was flying the two slower quicker planes before, some nerves, and my thinking about how heavy she is. I don't know how to make her any lighter.

After two flights, with no way to charge the batteries, it was time to head home. As I prepared to leave, I got in my car in the A/C, and watched John Warner fly a perfectly built, tuned and expertly flown plane, I think an Edge. Wow... If I had a flying ego I would have cried and thrown all my stuff out.

I will check out the 208b, expect to order a new one, fix the Sbach, and reset the crash clock from a record 123 days without a crash.

Flying the Hacker MX-2, MX-Bach RCGF-USA 35cc

Hot, Mississippi HOT!, But virtually windless. I wasn't entirely feeling it, but once I got everything in the car, I was pretty game! Took the Hacker MX-2, flying 3S. Its the first time on the iX12, had to program it at the field, made a few adjustments. Before leaving I decided to put slightly bigger wheels on the mains and tail, which helped, but she still would trip over the mains if ai wasn't careful. She has really super flexible mains, almost like paper... but I can land her super light, she's such a great flier, that its not much of a problem.

Fun flier!

First flight of the day with the MX--Bach. I was really distracted, not focusing well on the tasks at hand. I wasn't even there while flying my plane.  Unstable approach, unstable landing, tipped a little and prop strike...that was the end of the day. No other damage, so I'm not calling it a crash, though I guess technically it is... okay, fine, resetting the crash clock. I was flying a 19x8on this 35cc, the smallest recommended. I am 9ut of props for this one, so ordered two Turnigy 20 x 8 props, scimitar shaped. They'll be here in a week. Can't eat the price, $14 a piece.

Anthony was there with his 350, on the left, the 250 on the right benched for a split in the tail belt. He be humble, but the boy got skilz and it was fun to watch him enjoy himself. He prefers the smaller helis, something unique among pilots.

Well, the heat is something else, but that wasn't my excuse for anything. I wasn't feeling it today, though I flew the MX-2 well, but I was absent flying the MX-Bach. I just haven't felt much like flying lately, mostly because of the cost of the risk of a crash repair,and partly because I have been blue with all the crap going on. Today took  me away from all of that, and reminded me why I fly! Need to get the MXS-R and the Waco in the air, and get back to the 600's while I wait for parts for the 500.

It's all good.

MX-Bach Revisited

I am rethinking the MX-Bach. She started life as Kenny's 30cc MX2, and he gave me the airframe as he was breaking it up flying like a madman. I turned it into a 1.40 equivalent 10S electric (6S wouldn't fit). I had flown her I think a couple times, and broke her wing when an Ent grabbed her out of the sky. I still had the wings from my 30cc Sbach and thought, " why not?", and the MX-Bach was born. I flew her once. She has always been a bit underpowered, really needed 6S. I toyed with the idea but batteries are waaaay too expensive these days. I am not likely to fly her this way, and did try to sell her, but no takers, likely for the same reason.

I think I need to convert her back to a 30cc gasser.

This setup has 3-4 flights on it... I will be selling it when I remove it.

I'm looking for a used 30cc gas engine. I may end up buying new, but since she is a basher used seems more appropriate.

New Wheels on MX-Bach

I picked up these for $35 on eBay for the MX-Bach. 3.5 inch with aluminum wheels. Very high quality.

Except one the holes are not aligned.

On the other they are. Cosmetic difference.

Installed.

Very nice! A bit narrower than the DuBros.

Foreground is the MXS-R 30cc with its aluminum wheels, background is the new one on the MX-Bach.

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.

Today was a very good day.

Made it out to the SNHFE field in Merrimack today.  I brought out the MX-Bach having changed the old red Sbach Thunderbolts to green to match the MX-2 color scheme, the 10CC Sukhoi, and the new Great Planes Twinstar.

For a long time I have wanoted to change the red bolts and make the wings match the fuse, I finally bought some thicker self adhesive flourescent green cote and traced out the bolts. I used some lime green cote to edge it for comtrast.

I have some work to do learning how to fly her, and my other large scale planes. She flew well, despite me. Now she looks awesome!

First flight in her new colors!

Just before the maiden of the new Twinstar. She flew tail heavy despite her being on CG, so I had to make some adjustments. She is amazingly fast! Flying her 4S.

The RCGF 10cc Sukhoi 26 flew well, also despite me. On both her and the MX-Bach, and I suspect the 30 cc MXS-R, I have to figure out what the DR and Expo settings are that work best for me. I love this plane, and how that RCGF engine sounds. Others loved it too, and asked me about it. Hope I developed some more fans!

Kenny, Bobby, Tommy and new guy Dennis, working on Dennis' Kaden glow. Dennis got it free. He's worked a lot of RC cars and trucks, but is new to flying. Tommy and Bobby put it together for him and "maidened" it for Dennis. Hopefully Dennis will get to learn on her, and fly her soon.

It was a bit gusty, and the winds were from the north making the 36 Runway necessary, with its challenge of coming in over the Ents of the South. All in all it was a great day of flying.

My Hanger 9 Power Pro Starter has always had a twitchy switch. Hate it for that switch. I had taken it apart to try to fix it, which require disassembling the whole damn thing. It finally gave out completely today. Having nothing to lose, I bought a push button switch at Radio Shack and replaced the switch. It's fixed... there is still something not quite right about it, but it's working again. If it fails again, screw it, I'll get a different one.

Sbach Tip Stall and Vortex Generators

The Sbach and I have a long rich history of tears, pulling of hair and gnashing of teeth, mostly due to its unstable wing at low speeds and its strong tendency to severly tip stall into an unrecoverable death spin.

When I took the old 30cc Sbach wing and adapted it to the MX2 fuse creating the MX-Bach, it was necessity, not a love for the Sbach wing, despite its sexy shape, that made me do it. To address the tip stall, I sought a way to keep the lifties under the wing tips for as long as possible and to allow a more gentle stall. And voila, I discovered Vortex Generators.  Here is a great presentation on the concept, a video of experiments by an RC engineer.

I didn't, and don't, have the data nor the gumption to do all that math, so I just made some using L-shaped styrene strips, and installed then where I thought they should go, about 5-8cm back from the leading edge.  It's all described here.  I knew they would be tall enough, just picked a length, decided a V shape was nice looking, and stuck the buggers on. It actually worked! The MX-Bach has only flown a couple of times with the VGs, but she no longer shows the stall tendencies she used to. I think flying her at 10S made her a bit underpowered, so am very excited to be converting her to 30cc gas!

So as I prepare to build yet another Sbach, I am considering putting the vortex generators on her too. I will use the same guess work and install them similarly. I still have the L styrene strips. I think she is going to be an amazing flier!

Exhausted

Long day... I am worn out.

Took the MX-Bach RCGF-USA 30cc, with the correct wings, and the nudgey Stik RCGF-USA 10cc out to the field to get some quality air time.

I expected some engine tuning for the RCGF 10cc, but the receiver seemed to crap out. When I got home it worked fine when I rebound it. In the one engine run up the ailerons went rogue again at WOT. John Hayes suggested it was ignition noise, which makes sense because it only does it at WOT.  Grounded. 

At home I removed the stabilization system from the setup (it's still physically attached to the fuse), but run-ups once I got the receiver rebound showed that the rogue aileron issue is probably ignition related. I just could not get the damn engine to run right. When it would seem to be set, it would stop when pulling suddenly back to idle from WOT or half. I just could not find a sweet spot. Since the ignition wire is leaking signal affecting the receiver, and the engine just won't find its happy place, I am going to try a new ignition. I spent 3 hours in the backyard heat and humidity trying to get this to run. I don't know that it's the smaller carb, but I think I am going back to the original 10mm.

Adding insult to injury. the rudder came loose and then the vertical stab snapped when I turned it over to change the 3-way from a filter with a leaky to air gasket to a solid piece to reduce air leaking into the fuel line, which did decrease air in the line.

Lots of work to do.

This wasn't a crash...  I got the MX-Bach into the air after spending nearly 20 minutes trying to get her to start. Once she started I ran it for a while, then stopped, refueled, and she started up. Took to the skies sweet, well behaved, balanced, lots of power! Flew for about 10 minutes, basic maneuvers for trim and to see how she behaved, trimmed her slightly, wow, flying wonderfully. Threw the sticks around and had great control in aerobatics! Brought her down a bit, and pulled back the throttle, she backed down, idled, then stopped. She was high, and about 50 yds from the end of the runway, no wind. I dropped the nose and she nicely lost altitude, picked up a lot of speed of course, no room really to bleed it off, thought a moment about the flaperons, opted to keep going without. She touched hot and bounced a little, then came down but was doing a really hot speed. Rather than try a sharp turn I let her bleed off speed and she stopped at the edge of the grass. No harm, no crash.

And I could not get her to start again... Is it the carb? She was getting a lot of gas when I was working to start her, and runs well. Is it the ignition? It's brand new... I have no idea, but after a few tries to start it I decided I wasn't going to spend the afternoon at Mt Hudson doing the same thing over and over again with the same results, so defueled and packed her up. 

It was really time to go home. Meanwhile Clarence took his FMS Tundra up several times. I think I am going to start bringing an electric so I have something reliable to fly.

And then this... Despite being careful it snapped off, again, and moments later the wire broke. Poke me in the eye with a fork... This is why they now have solid masts. Guess I am buying another one. At some point I need to buy a new radio. This one is about 6 yrs old. I was hoping to find some kind of mod that was stronger... I may put a bolt through the hinge.

I am wiped out. I am not having fun. I think the idea of bringing a reliable electric plane out every time is something I need to give serious thought.

MX-Bach RCGF-USA 35cc is Up for 2020

Brought the MX-Bach down from it's bat perch on the ceiling to inspect and set her up on the Spektrum iX12. This is one of my favorite planes. I really like the larger engines, they seem to run better and tolerate weather and pressure changes better, start 'em and fly 'em! I had the wings on when I set up and programmed her into the radio, but forgot to take a pic.

Well, the clunk has a woodie... I really like the clear tanks.

The Tygon tubing is hard as a rod. I have been replacing these with Viton tubing.

Much better! Viton tubing.

The tank reinstalled. I think you can see it in the video the foaming from engine vibrations. Very little of that passes to the engine. At the bottom of the pic you see a pair of wires running over the side bulkhead. That is the ignition light wire I seem to have passed incorrectly, I cut the wires, passed it under the bulkhead, and used those melting heat-shrink connectors to rewire it as I can't get the plain on the soldering bench. I love those things! Push the wires with a small exposed end, into the tubing, one on each end so they mesh in the middle, use a heat gun to heat shrink and melt the solder. Voila!

The engine in run up. If you listen carefully you will hear the changes from Flight Idle to Approach Idle, and Landing Idle. I do this to prevent the engine from stopping in idle in fight, but slowing the plane down nicely. I hit Approach on final to slow it and as I cross the threshold I move it to Landing Idle, the slowest idle with a pretty reliable RPM. No needle adjustments, just had to find the new throttle end points on the iX12.