Firewall Solution: Building a Giant Scale RC Airplane from a pile of wood

[@ravebrave8866]

welcome back kokuda...we all wanted to see your cat...

[@chriskeithb]

Hey Dan, nice to see another video. I'm not sure if it's an issue for you, but a member of my club recently finished a beautiful Hawker Typhoon. He put a huge amount of work into it - fibreglassing much of the fuselage and great paint job. When he test flew it was very erratic and unresponsive, in fact, it came close to flying into the area where our cars were parked. Eventually, the model crashed on the field, needing some major repairs. The engine he was using had an electronic spark generator and we now believe it caused interference with his receiver - something that has been confirmed by further research. Just wanted to let you know so you were aware. Apologies if I am telling you something you are well aware of. Regards and thanks.

[@Capgains7777]

Wow, that is some some scary sh** when that happens. There is nothing worse than realizing your ship is out of control. There are a couple more tests that need to be completed on the Rebel. One is the engine run and tune, and the other is a range check with the engine on. With the advent of 2.4ghz radios we thought we got a break from rf interference from the spark plugs. And it is better, however not gone completely. The Decathlon had an rf problem initially. It took a while but I found out that the flying wires on the tail feathers were bouncing around with metal to metal contact and the servos nearby were passing it on to the RX via 36 inch servo wires. The elevator was bouncing like crazy at idle. I have had an ignition box go bad but caught it in testing. Another thing to check is that the spark plug is rf resistant. If the engine was a converted engine it may have a non resistor plug in it. So many possibilities. My heart goes out to your friend. It hurts so bad when something you spent so much time on goes awry. Makes you want to take up electric trains. Hope he can gather it up and make it better.

[@IamBlackdragon]

Thanks Dan on expanding on the balance, I read somewhere a while ago now that the carby is better off if in still air. My spacewalker I increased the hole size and added a velocity stack to the carb so it protrudes through into the fuse. Not sure if it makes a difference but having the hole behind the carby i beleive is a benafit for air flow to the engine. Looking fwd to seeing her fly. Thanks for the videos.

[@Capgains7777]

I have not had many exposed gasoline engines. Most have been cowled in so, sheltered from the direct blast of air from the prop. We will see how this one goes. The trouble comes from the little hole in the shiny diaphragm plate on the carb. If wind can flutter against that it will interfere with diaphragm and the engine will be stuck in a power sucking 4 cycle. The problem is, you can tune it on the ground but it won’t show up until you are airborne and flying with speed. The fix is to solder a tube or brass nipple onto the plate over the hole, and run a tube through the firewall giving the diaphragm a vent with no pressure. Its a pain in the butt because it needs to be mounted without sticking into the diaphragm chamber and touching the diaphragm itself. I hope being behind the engine shelters it enough.

[@TheBigChinoDon]

Guilty as charged, missed the last 10 seconds and didn't see Trixie. Have you considered using an IBEC so you only need one battery? I've had good luck with the PowerBox SparkSwitch, or the Tech-Aero Ultra IBEC. Either one makes it easier to worry about the charge on only one battery. I typical single-cylinder ignition module (like the DLE-30) will use about 400mAh. A 2200mAh LiFE battery should be good for about three to five 15 minute flights, depending on servos and how hard you use them.

[@Capgains7777]

Hey Don, good to hear from you!!! I guess on this build I just wanted to keep it simple and repurpose stuff I had available. That went out the window when I had to buy the DLE engine to keep the weight down on the overall build. I can understand these guys using power boxes on their $15k jet planes but overkill for this. Maybe I’ll try one on the Anderson LA-7 I have coming up. Its huge, and powered by a DLE 111 twin. Didn’t want my life getting too simple. 🤣

[@TheBigChinoDon]

@@Capgains7777 The 111 will be sweet in LA-7. I have a PCK cut Don Smith 100" Ki-61 kit that I've got to get to. Might use that same engine for that plane.