New shop floor "covering"

It was time to replace the interlocking foam squares that covered a 10x10 section of the shop floor as they were a mess after more than 3 years. I was tired of things bouncing off into the abyss, so this time I went with this holey design, hoping that wayward screws would be forced to narrow their bounce and be contained. We'll see. Its soft and comfy, easily moved for cleaning. The spaces between the squares seem to have permanently stained the concrete floor. I wondered if it was moisture, not sure why that would be, but a fan on it overnight changed nothing. It may be a more deep seated moisture that will fade with time.

450 FBL Update

The #2 aileron servo (port side) had a different range of motion than the #1 pitch servo (starboard side), causing a CCPM interaction at either end other of motion. I could not overcome this with endpoints for some reason, so I decided to replace the servos. I bought some inexpensive digital MG90 micro servos and tonight I installed them. Tomorrow I will program the ZYX Flybarless system and weather permitting test fly her! I will take her and the 450 Sport (flybarred) out.

Defeat

 

I give up. I can't get the Walbro carb to work on my 10cc RCGF engine, even after rebuilding it. When  I took it apart it was full of gas. Running it before and after rebuilding it I would see light smoke and a lot of fuel coming out of the exhaust, no matter how I leaned or richened or changed endpoints. It would never catch nor sputter. So I took it off the engine stand, and was planning to try the small 10mm Walbro I had tried some time ago, but in emails with Gary Hoffman, my engineer, I decided to bring it to him to have him hit it with whatever rocks he has. If he can't get it to run its not likely ever going to, but I will then have Joe Nelson Of RCGF-USA take a whack at it. I will be shocked if Gary doesn't get it running. Tomorrow I will take it out to Gary in Hampton, NH, on my motorcycle, two birds, one stone!

I may put the other RCGF 10cc on the engine stand, the one on the Spitty. I have had problems finding a nice low needle that idles well and accelerates well. Not sure, may just test it on the plane as is. I don't want to put the Evo 10cc on it, would need to see if the RCGF muffler fits as I am not putting the huge torpedo muffler on the Spitty, and also because I kinda think its weaker than the RCGF though I have no objective support for that. I had just found its sweet spot when I crashed the Sbach, so it was running perfectly. I'll give the RCGF a chance on the Spitty, but may replace it... we'll see.

New GT Power Servo Tester

My basic Turnigy servo tester is over 10 yrs old and was starting to show its age. In those 10 yrs I have also wanted to know things about my servos it couldn't tell me, like speed, dead band, etc. So it was time to replace it with an upgrade. I found the GT Power Professional Servo Tester on eBay for $30 shipped from hangarstuff4sale (gave you the MotionRC listing for detail).  I put it on a switch since it doesn't have an I/O switch, it turns on when powered up as far as I can tell, which meant it was going to need a platform, and here it is! I can easily charge the pack through the switch. Built a little box with a hatch to cover and contain the wires, used on old NiMH recieiver pack, some paint and Dual Lock and voila!

My trusty blue Turnigy tester will be hanging around for a while, for sentimental reasons. 

Walbro 10cc Carb Update

 I took the cleaned carb out attached to the RCGF-USA 10cc on the test stand.

She would not catch at all at first, but gas was going through it. Changed from the iffy new spark,mwhich was sparking, and used a good spark, no change. When I had it at WOT, she would try to run a few RPMs, but not consistently. After an hour I gave up, I was wasting a lot of gas to flooding. 

I took the carb apart, and it was full of gas. The valve sheet was rubbery. Now, the replacement kit comes with a least 3 types of material cut for this carb, one is kinda rubbery, one is this thin plastic, and another is a little thicker and looks reinforced. I have no idea which one to use, I've not knowingly used one over the other, and the blue one looks most familiar, so I went with it.

Put it all back together. In consideration of my neighbors, I don't run before 10 am, and usually not till noon, and stop after 5 pm. I will try again tomorrow. 

Updated Engine Test Bed!

 I needed my test platform to work on my 10cc carb problems, and I wanted to update it a bit. Put a throttle servo and an Orange receiver on it, added a second battery pack so I can run longer. Added a hole behind the engine to increase air intake airflow.

Its late now, tomorrow I will take it outside and run the engine whose carb I just cleaned.

Cleaning a Walbro Carb

I've been having carb problems. Pretty much anytime you have trouble with an engine, its the carb. The ignition and wires are second on the list. The rest of it is pretty tough and resilient to problems. I have been having issues with the carbs on both 10cc engines. These little buggers have such small tolerances for mixture that any debris or clog, and air leak, can cause weird stuff to happen that causes gnashing of teeth, sore backs from standing way too long to solve a problem trying the same thing over and over again because what you are doing is supposed to solve the problem. The machines are not hard, they just are complex. You've been there, don't lie.. If there was one thing I hate about gas its that the smaller engines are so unreliable day to day. The 20cc and bigger, probably the 15cc too but I don't have any, are so much more stable. So when someone tells you gas is reliable, they don't fly less than 10cc. Remember, the engine is fine, its almost always the carb.

I use this with the little red tube to blow out the passages and soak the carb.

I've take the carb apart but for the valves (throttle and choke). Both the metering and the pump side are disassembled, and the needles removed, including the metering needle. I don't peel off any gasket that doesn't want to come unless it needs replacing. The pump side gasket and valve sheet are fine, but the valve sheet might use replacing if I get one. For now its fine. I have cleaned everything thoroughly with carb cleaner spray, blowing out all the fuel pathways, soaking the carb to let any build up break away and flushing it again. I cleaned all the gaskets and the valve sheet with the carb cleaner. Carb cleaner melts gloves, by the way...

Here I reassembled the metering needle. Getting the metering spring under the round depression in the metering lever is challenging, and it must be properly seated. This will be the only frustrating part of the process, be patient. I use a flat micro driver to hold the spring compressed while keeping the lever in the head of the metering needle, and the hinge bar in its slot. Takes a few tries, and a couple of rounds of searching the floor on my hands and knees for a launched spring, but in the end it gets where its suppose to be. I don't Loctite the metering securing screw. Snug it in nicely.

Someone will happily sell you a fancy tool but any rigid piece or your Mark 1 Mod 0 Eyeball does just as well. The top of the metering lever should be exactly level with the top of the carb case. The other end on the needle head should move the metering needle noticeably when the lever is depressed, it is either open or closed. I find that the lever is only slightly bent when set properly. If this is screwed up the carb will not work well.

The metering diaphragm goes small washer thing side up. It should rest pushed out by the metering needle, Tapping it should have a nice range of motion and a quick rebound. If not the spring is likely wrong or the lever is not adjusted properly.

The metering cover is in place.

There are lock washers, but I still Loctite the screws, all of them except the metering hinge screw. I screw these down gorilla-tight.

Pump side. Gasket goes out, the valve sheet in, so that the flapper valves cover the fuel pump holes they are assigned to. Those are all the passages I blew out with carb cleaner. All of them.

Pump gasket and valve sheet in place. The valves should lay flat over the fuel holes they are assigned to. If not, the valve sheet should be replaced.

Pump side cover in place. I Loctite and gorilla-tight this screw. Make sure the gasket is properly seated, there are posts that usually assure this that pass through the gasket.

The fuel flow needles. They are different. The long skinny one is the low speed needle, the fat shorter one the high speed needle. They also have their own sized springs.

They go in their own holes. Seat the SOFTLY and completely. Walbro recommends both needles out to 1-3/4 to 2 turns as the starting point. You will need to adjust the needles. If you know what they were set at before you can try those settings.

Here the low is set to 1-1/2, the high to 2 turns.

The gasket between the crankcase and the carb is essential! It serves to prevent air leaks both ways, and to insulate the carb where the magic happens, from the heat of the crankcase/cylinder where the violence happens. Some engine use a spacer here to improve that insulation. I coat it with a thin layer of red grease.

There is a vacuum hole on one side of the carb, you can see it here. If your gasket has one small hole, it must be lined up with this passage or the carb won't work. My gasket happens to have two holes, one is vestigial.

Secure the carb to the crankcase being sure that the gasket is properly aligned. Use Loctite and again, gorilla-tight! The process is completed. Next, putting the engine on the improved test stand. I hope this cleaning solves the low needle/idle and acceleration issue. I gorilla-tightened all of the cylinder screws I could reach (two are blocked by the muffler screws, yep, Loctited and gorilla-tight).