"Nothin' Extra", by Northern Model Aircraft Co.

[Joker 53150]

So far high speed settings haven't made a difference, I've tried with the high needle settings from all the way in to about 2 turns out. It does make a difference in running at higher speeds, but everything at the low end just ends in the engine dying.

There are new gaskets on both sides of the carb mounting block and I've verified the gaskets line up with the pulse hole.

This carb has no choke, but I did try putting my finger over the carb opening (partially covered, half-covered, mostly covered). When the video was shot yesterday I had it running at a mid-low speed for a few minutes, plenty of time for it to warm up.

The clunk is a pretty good sized piece attached with new Viton gas line. The tank was about 2/3 full, and I even pulled the line from the carb to let the gas line drain a bit to make sure there were no bubbles in the line.

 

[Bricks]

Time to disassemble the carb and clean her out. But before doing that you could pull the needle valves out and shoot some carb cleaner thru where the needles sit and see if that will clean the junk out since you are not getting any adjustment on the needles some thing is definantley gunked up.

 

[Joker 53150]

Time to disassemble the carb and clean her out. But before doing that you could pull the needle valves out and shoot some carb cleaner thru where the needles sit and see if that will clean the junk out since you are not getting any adjustment on the needles some thing is definantley gunked up.

Agreed, I'll order another full rebuild kit and basically start from scratch with the carb work.

 

[Joker 53150]

Time to disassemble the carb and clean her out. But before doing that you could pull the needle valves out and shoot some carb cleaner thru where the needles sit and see if that will clean the junk out since you are not getting any adjustment on the needles some thing is definantley gunked up.

I decided to go an extra step beyond just spraying it out with carb cleaner. The carb has been pulled and fully disassembled, and is now soaking in denatured alcohol for a couple days while I wait for the carb kit to arrive. It'll still get blasted with compressed air, and this should (hopefully) give any built-up gunk time to fully dissolve. Worst case scenario is a new carb is needed.

 

[Joker 53150]

A few days ago I finished the carb re-rebuild. As mentioned on my previous post, it was soaked for a few days followed by being blown out with compressed air. Even though all the gaskets were new from the first rebuild a few weeks ago, I used a new gasket set, new needle, spring, etc. just to be safe. With the new airplane test-stand complete this became the first plane to be used on it, and I love how tall and wide it is, it really makes working on planes easier!

My buddy Mike came over to help me tune the plane - he's got a better touch at that than me. I put some Tru-Fuel in the tank (still loving that for my pre-mix as well), primed the engine, and we got to work. I warned him that the stock settings on the G-38 are very weird, and it took quite a bit of time to get it dialed in, but it now starts easily and transitions from idle to high to idle nicely. We probably could have had it done in half the time, but we didn't notice one of the screws on the pump side of the carb was loose and the air leak keeping it from running properly. It's still not "crisp" on the transition, but I'm not sure if that's possible on older magneto engines like this? Either way, it's running reliably and is ready for the re-maiden.

 

[Bricks]

Nice job once you get it in the air get some fuel thru it, when it unloads in the air you will find it will still need some tweaking. Those first few flights I would keep her a tad on the rich side slight 4 cycling. The crispness will come when you get the final tweaking down

 

[TooJung2Die]

A small Walbro carb like that doesn't have an accelerator pump. When you go from idle to full throttle there is a moment when it runs lean. It takes a second for the fuel flow to catch up with the increased air flow and it will stumble. You can mitigate this fuel starved condition by running the idle rich. I know this from tuning motorcycle and other small two strokes.

 

[Joker 53150]

Re-MAIDEN REPORT:

It was a bit windier than I like for a maiden, but I was confident in how this plane flies and the engine runs strong. It did take about 3 ounces of lead at the tail to offset the heavy engine, and could possibly use an ounce or two more. It fired up immediately and ran great for both flights, and comparing against the previous electric setup it has less low end torque, but faster overall speed. Flight times should easily be over 10 minutes, probably close to 20 based on the huge gas tank.

Coming in for landings, it still doesn't want to land and keeps floating, even with the extra weight.

Post flight report shows three issues which need to be addressed. #1, one of the flap hinges is coming lose and needs to be re-glued. #2, I want to change the straps holding the gas tank down so it's a little more secure. #3, I need a new muffler as I forgot to tighten the bolts after swapping mufflers yesterday... We noticed it was loud while flying and never realized that it was due to a missing muffler. The B&B mufflers are normally a bit louder than normal. Oh well, easy fixes, and it'll be much more fun to take to the field now.