PulseXT, Electric Starter Issues, and the Stik Servo

Made the throttle servo swap on the PulseXT 60 with its RCGF-USA 20cc It's a powerful 20 kg torque servo, but it was less than $18 from Amazon. I put a ferro ring on the lead and it has a plastic servo arm, so it should be well isolated.  The FUTABA servo was an old piece of crap and had a bad wire. I hope this solves the mid-range twitchies.

I mentioned in the last post that I fried my electric starter. It should be more than capable of handling the compression of the 30cc gas engine, but these RCGF-USA engines are known for their hight compression. With the issues I was having trying to start the MX-Bach, I melted the plastic around the contact bushings. I also found the old parallel cable I had made was coming apart so I rebuilt one. I used the bar from a couple of Traxxas connectors and soldered the leads to them, used shrink tube to cover it. Works great with my new Hangar 9 starter!

I also changed out the wonky Hitec HS-435HB servo on the Stik's tight aileron. Rock solid. With that and isolating the ignition noise. Looking forward to getting her up in the air!

MX-Bach Update

Finished a lot of work on the MX-Bach.  Rebuilt the fuse, and as discussed earlier built  new set of hardpoints for the gear. I purposely isolated them from the more fragi\e framework of the fuse. 

I decided not to fylly replace the stringers and just repatched. I used some more sheet balsa than was there before.

I was bored so I did a lot of darts. It helps break up the wonky framework.

I used screws allowing me to open the fuse to access the landing gear hardpoints in the future.

I put shark teeth on becasue I could.

Because I was still bored I used reflective tape on the nose cone fully aware that it would peel off. The cone broke under the load of  burning out my Hanger 9 Electric Starter.

So the down side is that I spent hours today trying to get the RCGF-USA30cc started. It didn't matter how I tried to tune it, but it would only start really rich. I finally had to give up. I suspect another bad carb. When I did get it running she would seem fine, held WOT fine, but then started pulsing and then quit. I am working on getting another carb to try. Makes no sence, the carb looks fine.

Tray table upright and locked, and servo jiggles

Gorgeous day, out this morning just before noon to take the Stik and the PulseXT60 up.

Never a day when I just go out, set up, start an engine, fly a few times, pack pack up, home for a beer and a cigar.

The RCGF-USA 10cc engine ran fine. I had managed to shield the servos from the ignition noise. But in the meantime the right aileron servo fried and now locks up slowly and won't respond. No Fly For You! Ordered a new Hitec HS-485HB to match the other side, from Amazon Prime.

Tray table upright and locked...

But at least she ran well!

Flew the PulseXT60 , still not happy with the engine tuning. I took the cowl off and retuned her, got most of the mid-range 4-cycling out by leaning the high. Realized as I was watching her that when she is running the throttle servo jiggles in the mid-range. I think its a bad servo, several of the servos given to me when I bought the kit have failed and I think this one did to. I ordered a standard digital servo from Amazon Prime.

I do like to support my LHS, but one never quite knows what they have in stock, understandably they can only stock so much. Amazon Prime gets it here at a good price in two days. Capitalism sucks.

Repairs on the MX-Bach

The carb bolt/reed block debacle aside, I got a lot done fixing the landing gear hard point and repairing the fuse.

I first made the hardpoint attachments that would sit on the side walls of the undercarriage, supported by the long  plywood attachments that would run most of the length of the sidewalls.

I used the old hardpoint to set the spacing.

It fit perfectly. I replaced the silver screws with cap bolts after epoxying it all together.

Everything set with 30 min epoxy and clamped in place.

I devised a way to use self-setting nuts and attache the gear directly to the metal hardpoints, removing the wood hard point altogether. I spent the rest of the day repairing the framing of the fuse.

Working on repairing some cracks in the temporary nose cone and repainting it. I am also painting the plate that the fuel vent is attached to. I will install it and close the cote.

Once everything is back to repaired, I will troubleshoot the engine and start all over.

How stupid am I?

Pretty damn stupid.

As a result of my deadstick landing kerfuffle, the engine compartment was full of dirt. I started the repairs today and cleaned out the compartment, and removed the engine to clean the carb, as the engine being covered in dirt, surely there is dirt in the carb. Unmounted, took the engine apart, setting aside the carb, the pulse/insulating compartment (that black thing with the hose in the pick), the reed valves and the engine block. Mental note of the orientation of the carb on the block, check. cleaned the carb, a little dirt, the engine block was fine, the reeds needed some cleaning. All is well. Reassemble.

Well, that's weird. I didn't notice that the insulating block had such gaps... and so I made a gasket, and screwed it all back together, but the carb bolts were too long, and the ends were in the engine block, stopping the crankshaft from running. Jeez... Well, let's cut those long ass bolts and reassemble it.

Why the hell do the bolts go so far into the engine block. Who designed this??

So I reassemble it, insulating block, reed valve (wait, what?), carb, but now the frickin' screws are too short. And I didn't even cut them the same size... 

Oh, for the love of all that's holy... I am so frickin' stupid. And that's putting it lightly. 

This was a cluster the moment I first put it back together. See, I left out the reed block the first time I put it back together... so of course the screws were too long. My first stupid was forgetting to install the reed block the first time. My second stupid not stopping to recognize the engine ran just fine without me cutting the bolts. My third stupid was cutting the bolts.  That was the unrecoverable stupid because I don't have replacement M5 - 60mm bolts. Now I have to wait for my order to arrive from RTL Fasteners.

So, that's how stupid I am. Well, I wanted to take a break from this plane anyway...

Family Photos

My wife took these from the back deck while I was working out of my basement workshop on setting up and running the RCGF-USA 10cc on my Ugly Stik. The wing is on so I could test the rogue aileron issue having also addressed the spark cable signal noise. This is such a nice plane!

New Carb, New Life, and Ignition Noise Ousted!

I have had issues with this RCGF-USA 10cc gas engine for several months after several years of great operation. I figured out there was something wrong with the old carb after a bit of screwing up the motor during a rebuild when I broke the piston ring and did something to the original carb that made it wonky. I replaced the piston ring, and I tried a smaller Walbro carb, I think 7 mm from the original 10mm as people argued the 10mm runs the smaller engine rich. I could not get the 7mm to run well. I bought a new 10mm stock carb from Joe Nelson at RCGF-USA and installed it today, and she ran well with minimal tuning. The high is a bit rich: mildly rough 4 cycling in the mid range and when pulled back from WOT she drops a bit lower in RPM then works her way up, but I tuned it as lean as she would allow and its mostly gone now. Runs great, will fly her in a couple of days.

John Hayes offered that my rogue ailerons at WOT was ignition noise. I pulled the ignition and the casing of the spark cord is frayed. It did not like being crammed into the forward compartment for all these years  Covered the frayed parts with electrical tape and shrink tubing, left the cable outside the compartment and voila, no problem!

7mm on the left, stock 10mm on the right.

I like that I can remove the throttle arm, which was short and a bit different than usual. I replaced it with an aluminum servo arm. This engine has a choke; the 7mm did not and was always a challenge to cold/dry start.

You can see the rubber cover is pulled away from the casing, and the wires of the cable frayed here, and a bit further down rubbed down a bit. I used thick shrink tube for the casing end and electrical tape for the middle fraying. The ignition noise is gone!

You can see I left the spark cable outside the compartment.

Underside view. You can see the choke arm and the throttle arm.

Another view of the choke and throttle.

Runs great, no ignition noise effecting the ailerons!

Can't wait to fly her day after tomorrow!

Baby learned a new trick...

I had a half day, and a bit later than I planned (lazy) I got out this morning with the MX-Bach. She started with the electric starter, and ran pretty well, though she had this stutter thing that I was pretty sure was just a little 4-cycling in a 2-stroke. But some of the pauses are pretty long and not a quick sputter.

I catch some of the 4-cycling behavior here, none of the solid pauses.

As she idled she initially seemed happy pre-flight, and out of the blue just stopped. Restarted, and she again ran fine throughout her range, ran her up and down a few times, every thing was fine. So I took her up, and she flew so incredibly fine, smooth like buttah, some light aerobatics, and running through her throttle range. Let her idle high up several times, sweet, no issues. Plenty of power. Ran her down the line at altitude WOT and suddenly nothing. It just quit. No slowing, stuttering, racing, just quit. So suddenly I would later wonder, "Did I hit the kill switch?" I trained myself so that when the engine does die after moment to ensure proper control (aviate-navigate-communicate) I instinctively hit the kill, so I don't know just when I actually did.

Sweet deadstick approach, landing a bit hot, touched down nicely but then bounced and...

Pleased with the approach and initial touchdown, but annoyed I let her bounce and ripped the gear out again. Lots of work to do. For now I am going to assume that this was a one off, and get the gear fixed, restart the engine after replacing the prop. Should I swap out the RCGF Ignition for new one I have on hand, or is this the Hall Sensor? Maybe I swap out the sensor first, least effort... If she just wasn't such a stable sweet and smooth flyer.

I noticed that only the right elevator moved when I set in some trim with the flaperons to give her a bit of nose down. Not sure why the left one didn't follow. Need to sort that out. Is it a mix? This wasn't a problem before...

Resetting the crash clock.

Hangar Day

I had to wait for the new DX8 Gen1 Antenna to arrive, and Amazon delivered it damn near next day. It arrived this afternoon and took me a couple of minutes to install. 

Once I had it installed, I took the MX-Bach outside and took Joe Nelson's (Owner RCGF-USA) advice and used my 12V electric starter to get the new 30cc engine to start. As he said it would, she started right up! Got her idle settled, I believe, so I am very, very happy about that. Was going to take her out to fly but someone said, "Lunch at the Beach Plum?", so that happened instead. 

When I got back I decided to fix the wonky and broke vertical stabilizer. on the Ugly Stik. That thing has taken a beating over the years.

I removed the vert stab, and if I had given it any thought whatsoever, I would have repaired the cote on it then, but no I did it the hard way, repairing it after I reinstalled it. Here I have removed the stab and drilled 4 holes for posts to help strengthen it.

I mirrored these on the bottom of the vert stab. Thought I had a pic of the posts... nope. I just used "match stick" wood.

I used 30 min epoxy to install it, and after a couple of hours, I epoxied in two runners, one on either side of the base of the vert stab to stiffen it, also using 30 min epoxy.

Re-coting the stab was not as easy as it could have been, but this thing has been repaired several times. The cote is quite a patchwork.

The "American" on this side interprets the German on the other, a play on  Shakespeare (see what I did there?).

In preparation for the new 10mm stock replacement carb I ordered from Joe, I removed the 7mm smaller carb I tried out. I don't know, maybe it would work fine, but I have had more trouble getting and keeping her running and tuned since putting the smaller carb on. The thought is that the 10mm carb is big for this size engine and tends to run it rich. That may be, but I think this small engine prefers to be rich because even when I had her tuned as well as I could, I could not get her not to stall out on pulling the throttle back quickly from WOT or half even if I slowed the servo speed. If I eased it back, she tolerated it. I am going to send that smaller carb to Joe to play with. It wasn't designed for RC aircraft, but he is good with this sort of thing and it may be better for the engine in the right hands.  Once the carb is in, I need to check out the ignition and maybe replace it to see if that is the cause of the ailerons going rogue, usually full RT roll, left full down, right full up in a spasm, then it returns to normal, just at WOT.  Is there a noise leak? It happens with the two receivers I tried so I know that's not the problem. The receiver is way back in the fuse. I need to research how to further shield it...

The Stik has been ridden hard since I got her back in July 2016. She has been my go to gasser, capable, stable and predictable, my Alpha 450 with power. Her engine has also been the most cantankerous... but I have learned a tremendous amount from her. Looking forward to getting her back to reliable flight status.

Well, this is good.

She starts and runs awesome! She stopped running in flight the other day and I could not get her to start. She has been very challenging to hand start. When I mentioned this to Joe Nelson of RCGF-USA he smiled (it was an email, but I know he thought ti funny I was working my wimpy biceps so hard) and suggested not trying to hand start her until a couple of gallons went through her. I put my 12V starter on and shaboom.! Right away, ENGINE NOISE!  Adjusted the idle, which I think lead to the deadstick, and she seems rather happy. Once she warms a bit and breaks in more, I expect to be able to lower the idle a tad more, she is just barely producing thrust at idle.

I did swap out the nice carbon fiber nose cone for the painted Ultimate Style one so I don't mar the nice one.

This motor tried to lift the back of the table off the ground! Some kinda power, and what a sweet sound!

Baby, Daddy's goin' flyin'!

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.

Wrong wings? No problem!

Finally my vid is out of Google Video Processing Purgatory!

Took the MX-Bach out t the field to "maiden" with the new RCGF-USA Stinger 30cc gas engine, and brought the wrong wings.... I wanted to get time on the engine, so I drove it around for a while. Right now she is really difficult to start, but once the carb is wet and she runs, she really runs sweet!

Planning to fine my mojo and get out to the field today to fly her. sorry about my finger in the vid, trying to operate the radio and hold the phone at the same time. I never quite get her to WOT as she really hauled butt...

While my vids are in Google Hell...

For years Google Photos has had this awesome behavior where it will randomly decide your video will be stuck in "video processing" for hours, days, months in some cases. You can watch it on Photos, but that is it. Can't download it, can't share it... it is no longer yours. Some thought it was the  file size, one of mine is 64mb. Curiously one of them is a little smaller and it was available right away. You would thing this years long issue would be fixed by now... This one below was processed right away and I was able to upload it to YouTube.

RCGF-USA Stinger 30cc

Somehow when I installed EC3 connectors I got them backwards, the Male-Female is set up Female-Male. So I had to make an adapter, and in this pic a small plug in the middle to allow me to charge it. I didn't feel like changing everything, and I am out of connectors. I put solder in the wire receiver end, a small cut piece of a M3 screw in that, and then soldered the free end into the other connector, so that M-F were soldered back to back, then the female metal part inserted into the male plastic connector. I know, more than you need to know, but it was a slow day.

The Sbach 10cc Evolution has its place in the workshop.  One of the videos I can't access is a walk around while she is running. Flew several tanks and figured out her trim, and her DR and Expo. She is flying wonderfully. The vortex generators have made her stall habits much much more benign. 

 

I picked up this Hobby Eagle 3-Axis Gyro from MotionRC for around $30 delivered/ HobbyKing doesn't seem to be brining their Orange Stabilizer systems back anytime soon, so I will give this one a shot. I am thinking of using it in the Sbach.

Hopefully I will get my videos back soon. If not, planning to "maiden" the MX-Bach tomorrow, weather permitting.