All my planes are in flying status! I also figured out that I had somehow changed my phone camera to the lowest video quality setting, which I fixed, but this next one is poor quality...
The Pulse XT60 with its nicely tuned RCGF-USA 10cc with the new throttle servo is running smoothly. I also put another magnet on the front hatch hoping to keep the air pressure from popping the back up. I think that's how I lost the original. I may have to create a vent in the underside of the back of the fuse. There isn't a lot of airflow under the cowl, that may need to be addressed too.
I picked up an exhaust silencer from MileHighRC for the very loud RCGF-USA 30cc on the MX-Bach. I know there is a small WOT RPM loss but think it should be minor. For some reason this engine is very loud.
The silencer slips into the exhaust pipe.
And sits loosely just a bit out on top.
I cut an appropriate length of the silicone and used one of the supplied thin ties to secure the end of the silencer, and one of my wider ties to secure the silicone to the exhaust. I had to stretch the tubing a bit, so it fits very tight on the exhaust and the silencer. I doubt it will go anywhere. We'll see how she runs with it.
UPDATE: Video with and without the silencer. I will eventually do decibel measurements. All in all it does seem to have a less high pitched sound, and the effect on RPM/Power seems qualitatively negligible. When I do the more formal test, I will record them and provide better quality video.
Without the silencer. Poor quality video and sound. Not really good to compare.
With the silencer. IRL you can appreciate that it takes out the piercing high tones and gives the engine a deeper voice.
Beautiful weather, got some flying in today. I brought out the MX-Bach RCGF-USA 30cc newly sorted out, and the Stik with its cranky RCGF-USA 10cc.
Given the large openings in the cowl, I used a piece of filter material and created a flap of it over the intake of the carb. Works perfectly, allowing full movement of the choke, yet pretty much covering the entire intake. Between the back facing intake and this thick piece of filter, I think we got most crap covered.
It always something... The tail wheel lost its turning lever so it's castering about. Worked fine, in fact, not in any hurry to fix it.
Preflight.
Curiously off center pic... She flew AMAZING. Started right up, no tuning, and flew with some incredible power. While stable, in turns she requires your full attention and a little opposite rudder or she drops like a stone. But boy, can she maneuver and haul butt! She sounds amazing! The landing gear held up nicely.
The video saved in some crappy format, sorry for the poor quality.
For scale. She is a big, big plane. Flew her for a full tank then took the Stik back up. You know that feeling you get just before you break your leg in that "just one more ski run and we'll call it a day" ? I got that when I thought about ending my day with another tank, so I called it quits.
I actually started with the Stik. Not to disappoint, she took 10-15 minutes to sweeten her tune, but then she flew perfectly. One foray into the weeds when she would not veer right on takeoff and didn't have enough to climb over the weeds, but other than that, she flew wonderfully. She still has this rare habit of quitting at idle for no apparent reason, no stuttering, slowing just stops. Came in for a landing, taxied back round for another take off, paused and she quit. Started right up and acted like nothing happened. I flew a couple of tanks in her. Stupendous!
Right after she stopped. Was about to film how sweet she sounded...
One of the two reasons I don't fly bigger than 30cc. Its the biggest that will fit in my car, and the cost is at my upper end of willingness to spend.
At some point during the drive over I poked a hole in the right horizontal stab, used "field cote" to cover it, repaired it when I got home.
Nice to have a very successful day flying. Went with two, came back with two, and nobody took all day to run right!
I had been having problems with the RCGF-USA 30cc installed on the MX-Bach. I took the engine off and studied it, removed the carb. I just could not believe it was the Walbro carb, the ignition or the Hall sensor. I decided to look at the vacuum port on the reed valve casing, and found it hard blocked completely. There was no pump vacuum. I suspect this was building up, there being as is standard no air filter. Cleaned it, reassembled, and she started up right away with the low needle at 1.75 and the high at 2.25, and she runs sweet! Drove her around the yard with no problems.
Reed valve side of the vac line.
Vac port, on the pump side of the carb.
Clean reed valve.
The reed valve side vac port on the reed valve case.
The blue tube is the vac line from the reed valve case to the pump side of the carb. Reed valves poking out.
Put the carbon fiber nose cone on here. I CANNOT WAIT TO GET HER UP IN THE AIR!
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!
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.
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.
