Tune Up Day for the Stik's RCGF 10cc

Last time I flew the Stik she had some challenges getting and staying tuned. The QuikFire Filter is nice, but I am not sure they offer an advantage. I like the filter system on it much better than a screen, but honestly I don't know its any better than a simple screen filter. Certainly its costlier. I don't know that I will include them in my next build. This one leaked, so I replaced it with a simple 3-way screen filter. The engine runs so much better.

I simplified the fuel system.  Kept the QuikFire clamp and used it to hold the 

screen 3-way filter in place. This cleaner approach to the engine from the fuel tank

made for a much smoother running engine, in particular with shifting

fuel demands in aggressive throttle management.

The RCGF 10cc engine continues to be a bit of an enigma. I still love them, and don't think there is a better, more affordable 10cc engine. But I have to admit I have no idea which way to turn the low needle... Conventionally you tune the high end for max RPM, and that needle is easy. Then you tune the low end for smooth fast full throttle. One would think that if it bogs down, you richen it, turn it out. The idea being that it needs more flow. You find the leanest point that gives you a smooth, non-bogging transition. Tuning the low needle is a constant challenge on this engine. The other traditional bit is that once you get a gas engine tuned, that's pretty much it for the season. One of the reasons I like my Stik is the open engine bay: no cowl to take on and off, because it seems I am constantly having to re-tune the low needle.  I haven't flow the 26cc much, as I finished the Waco last fall just as the winter closed the flying season, but in the short time it seemed much more stable. The fact is, though, that I am breaking in a new cylinder on the Stik's 10cc, so it is expected to be a bit wonky.

Running the 10cc idle to full, half to full, back to idle, after the tuning. Max RPM and smoothest I could get the transitions. Too lean on the low needle and she would quit sometimes in idle, especially dropping from full throttle. Kept having to shift the low endpoint on the transmitter to find a good balance that gave me a reasonably low idle without stalling the motor on full throttle and on idle back. She seems to be running pretty smooth. I will be in Londonderry tomorrow for an appointment, so will pack up a couple planes to fly off the mountain top in Hudson at SNHRCC. We'll see how she does.

Looks like the gang at Misfits in Auburn have accepted my membership! The field is closed due to mud on the road in and the parking area. Once it dries I will be doing more flying out there. But for the need to have a buddy, the geotex is awesome, and the open space makes for better flying. I love the gang and the geotex out at Flying Eagles in Merrimack, but just hate flying in and out of "The Hole" of the trees that surround the field.

I am charging the packs on the Stik and the Sukhoi 10cc's, and some 3S 2200's for the HobbyKing foam Sbach to fly tomorrow. The winds at The Mountain are always a bit more brisk than the prevailing winds, so it may be a bust when I get there, but we'll see.

Finally got some flying in....

Finally. A beautiful day off with sun, little windy. The stablizing system came in handy.

Joppa Hill Fields in Bedford suck. The grass is so clumpy that my Stik with 4 inch wheels bounced madly and frequently got stuck, stopping the engine with prop strikes. Takeoff took almost 50 yards! The gound is mushy, saturated to boot.

I spent an hour trying to get the engine running again, now that its warm out... The low needle setting just would not find a sweet spot. The needles are out over 3 turns, anything less and she would not run. Ffinally found a good high, and an acceptable low. She didn't stall at idle or full throttle. She is running a lot rich, I suspect due to the new cylinder breaking in. If I lean it out I lose a lot of rpm. Tuning it I ran two tanks, almost 25-30 minutes of run on a tank! She has little vertical, but flies aerobatically fine and sharp. Put her through some paces and she stayed on line, held her speed, and turned crisply. She is predictable and fun to fly.

I need to remove the QuikFire fuel filter. Its leaking. Maybe I can fix it. The plane is flying a bit tail heavy, so I can't loose weight, but the fulter is sooo light so probably won't matter.

My fingers and head were in the game, no problems not having flown much of late. She idles high so comes in hot, but easily manageable.

It was a good day! Felt great to fly. But the field SUCKED!

I just bought a house out in Chester, so will be joining the group that flies off geotex, the NH Flying Misfits in Auburn, off Lake Massabesic. That wil end this nightmare filed condition issue.  Its a nice open field. Can't fly solo there as its next to a full scale grass runway, but that's easily managed. Looking forward to it!

Skiis, Hardpoint and Stabilization Success

Got out and up yesterday. Cold 30 deg in the sun, calm with mild variable gusts. It was time to test the skiis, the newly revised wing hardpoint and the stabilization system on the 10cc BigbStik.

A light snow in the morning, but most of the deeper snow has melted off. At this side it's shallow with grass poking through, on the far side about 6". I walked across to fly from the other side as is my new preferred side. It's that hard to walk on iced over snow

The new hardpoint addition. I redid the post on the wing, and added this extra piece to secure the anterior edge of the wing. That wing post hard point takes a lot of forces and I didn't want to depend on it alone. Worked perfectly, even in wind and aerobatics.

Wing attached. You can see how the wings snugs up under that new piece.

Today's tarmac. Using the wing bag to kneel on, trying not to make footholds in front of the plane so it can slide out for takeoff.

One of the issues with the skiis is that they offer virtually no resistance to thrust, so even at idle the plane wants to scoot off at high speed. This also makes roll out after landing a bare knuckler. This was a problem today. I gave it some thought when I got home and decided to use some of the L-rod I have for making vortex fences and CA'd some Vs to create a little resistance.

Tail ski. The hollow hardpoint twists against the Shea of being used as a tail wheel, so I filled it with epoxy.

Mains. Trying one set each side.

In flying with the skiis for the first time she flew a bit tail heavy, and there is a bit more drag. I pulled the few oz of weights off the tail and will recheck CG. I didn't do a CG check before this flight, which I realize was a mistake I got away with. Clearly the tail ski is heavier than the tail wheel.

Also on my last flight I toggled the stabilization system with the mechanics gloves I fly with in the cold. I use the F-mode switch on my DX8-orig, right above the ignition kill switch, left side. My finger usually rests between the switches, but with the gloves I have to keep my finger below the kill switch. To toggle the stabilization system I simply slide my finger up (on) or lift it over the switch and pull it down (off). Yup. Killed the ignition mid turn in a tail wind 10 feet AGL. Landed fine but in the middle of footprints in the snow without any slowing (skiis remember) so she was still shooting across the ground and she eventually tipped. That snapped the ceramic top off the spark plug which hangs under the cylinder which hangs under the nose, which was probably quite brittle and cold, despite the engine heat.

I had tried not using a gasket on the muffler header. It sprayed post combustion oil all over the place aft of and around the header. Got some gasket material today and will cut a gasket for it today. Back when I replaced the cylinder I noticed that there isn't a gasket between the cylinder and the engine block... I wonder if that is where some or all of this oil is coming from?

Replaced the spark, made the "ski draggers", new gasket. Waaaaay too cold today with heavy snow, but maybe tomorrow we fly.

Big Stick Forward Wing Hardpoint Failure

It was frosty, 26 degrees, zero to 8 mph winds, but sunny. The snow was frozen on top but I thought I would still get out with the 10cc Stick on skis. I installed the large Du-Bro skis up front and a single Du-Bro park flier ski in back. Easy install, work fine. And slippery...

But the repaired forward wing hard point failed, fortunately on the ground. I need to come up with a way to firmly attach something to the wing to act as the cantilevered forward attachment to the fuse.

Hung the camera from my neck strap.

So disappointed that after getting my gear out to the field to not get to fly. At least this came off before lift off. That would have ended poorly. Trying to think of ways to fix this problem. I don't have much space under the wing, none in fact forward, as the fuel tank is right there. This limits bringing a long piece back aft for better leverage.

Slushy Fields

Too slushy... gone or frozen over would let me fly. The Du-Bro skis for the Stick and Cubby are on their way.

The slush really outlines the serious clumpiness at Joppa Hill Fields. Surely this affects the kids play as much as the landing gear on my planes?

RCGF 10cc Cylinder Head Changed Out

I ordered a new cylinder head from RCGF-USA for the 10cc engine whose spark threads had stripped. It arrived today and I installed it, and started the engine.

It oddly did not come with a new gasket, which would have been nice, so I took care removing the old one. After removing the old cylinder head, I oiled down the new one with WD40, slid the piston in (the piston ring passed easily this time. Bolted it in place, reinstalled the muffler/header, took her out and started her up. After she burned off the WD40 she ran just fine. There is some 4-cycling, but she is a new cylinder head. I put a Master Airscrew Scimitar 14x8 on her for the break in, then I may or may not put the 4-blade prop on. Who am I kidding? Of course I will eventually put the 4-blade prop back on...

I also learned a couple of things I can do to save the other head. I can try re-threading the 1/4-32 plug (of course my 40 piece tap and die set doesn't have that one so I had to order one from China).  I can also drill and sleeve the threads with a kit. I want to see if I can make the repair to the threads so I have a new skill and a working extra 10cc cylinder head. 

Ran half a tank at various speeds, tuned her a touch. I am off Saturday, so if weather permits I will fly her and continue the break in.

A Bad Bulkhead and RCGF Spark Threads Strip Again

I ran the engine today with the 14x8x4 prop and it didn't come flying apart. It started and ran fine, but stalled in idle after a few moments. During that time the prop was fine, stable, and tracked perfectly without bowing, and no vibration. The second time it stalled at idle I could not restart it. I took it into the shop and I removed the spark plug to check the ignition and it sparked, but inconsistently. I decided to replace the Hall sensor and it fixed the spark problem. The Hall sensor frame had snapped and in repairing it it sat a bit higher than I think it should. I could not get the sensor head out of the case, so I had to replace the entire thing, and I just happen to have a couple.

I noticed that when I removed the spark from the RCGF 10cc engine, I noticed a "spring" in the hole. It took me a moment to realize that the spark hole threads had stripped. This has happened before as RCGF had a problem with the early engines they supposedly fixed where the threads were too soft or something and kept stripping easily. I replaced the spark and it threaded "finger tight". I tried turning it over and gas poured out... I could twist the plug with my fingers, it would "tighten" and then a half twist and it was loose again.

I ordered a new cylinder head. I hope these replacement heads have better threads.

When I noticed that the threads were stripped, I was concerned that some pieces fell into the cylinder head. I decided I needed to remove the entire cylinder head. Two of the screws came out easily, but two were blocked by the muffler header screws. One of them had stripped a while back... so I had to remove the entire engine to find a way to get the muffler off, and had to remove the prop. One thing leads to another...

I pulled one screw of the header easily, the other I could not get any purchase on. I twisted the muffler and it loosened. I managed to twist it and the screw got looser and looser, and eventually I could not turn it anymore. I grabbed it with a pair of needle nose pliers and managed to completely remove it! I got the cylinder head off and it was heavily carboned. The cylinder head was rough, like 60 grit. I used Gum-out and cleaned it all to nearly completely shiny. It took a few minutes to get the piston ring back into the cylinder head, but then it moved nicely. I used some WD40 to lubricate it. I put it all back together. That's when I tried to put the plug back in. 

Waiting for the new cylinder head. 

Earlier I kept hearing something rattling around and wondered if there was damage inside the frame where the fuse had been cracked. I opened the access panel I had made when I first built the plane, and found that the frame behind the firewall and in front of the gas tank was broken. I cut some ply into a U shape and divided it to get it in. Epoxied it. I added a couple of cross braces on the top, bottom and middle. This was easily done and came out perfect. This pic is before the crass braces. 

When the cylinder head is repaired, I hope to tune the engine for the new prop. Its very light. I have no idea if I will keep the 4 blade, it was more for fun than anything else. I wanted to check the static thrust, but the engine stopped working before I could.

So she sits on the bench. Hopefully the cylinder head will get here soon.