piper_chuck

My Feedback: (12)

My youngest daughter will be a high school junior this year and the older one will be a junior at University of SC, go Gamecocks. After years of driving them to various activities including soccer, track, cross country, marching band, swim team, etc, I think I finally have time to start flying again.

I've started going through my beater plane to get it ready to fly again. It's a World Models Combat Zero that I bought over twenty years ago. To say it's ugly is an understatement. The only resemblance it has with a zero is the green color and the red rising sun emblems. However, the plane flies great and has been very durable. I call it my beater plane because I've flown it hundreds of times, don't baby it, and it just keeps going. When this plane finally meets its demise, it happens to all of them, I also have an unassembled WM Aircombat YAK which has the exact same shape but different color scheme to replace it.

I originally assembled it with an OS .25 FSR but swapped that out with a .32 FSR. The .32 has been an amazing engine. If I fly it with a 10x5 prop, it takes off in an instant and will climb forever. Swap that out with a 9x7 or 9x8 and the plane is remarkably fast. The overall weight is low and slow flight is very predictable.

So far here's what I've checked:
Thorough radio checkout. Over the years I have occasionally charged the transmitter. It's holding a good voltage but to be safe, a new battery pack is on the way. The same goes for the flight battery. I've gone through all the control surfaces to confirm the servos work right, that they're moving the right way, and that the linkages are sound. I also confirmed that the hinges are solidly anchored.

Engine and throttle movement. At the end of a flying day I always ran out the fuel and added Marvel Air Tool oil to lube it. It turns over freely, the bearings feel good, and compression is still strong. I'll install a new glow plug before I fly.

The fuel lines are still good. I need to flush the tank a few times just to be sure it's clean. I don't see any gunk when I do a visual inspection, but I can't see all of it unless I remove it.

Now for the questions.
First, I have several APC props which I have never mounted. They have been stored in the house since I bought them so they have not been subject to excess heat or cold. Do these degrade over time or should they be ok to use?

Next is fuel. I still have a full bottle of Omega 15% from a long time ago. Is it worth trying some test runs at home with this, or should I just recycle it?

An finally, what else should I go through before I put this in the air again?

LLRCFlyer

Welcome back to the hobby. I have used many old APC propellers and age does not seen to affect them if they were stored indoors at normal temperatures and away from sunlight. Just check them for balance, cracks or other mechanical damage. As for the fuel, that is a "maybe". You did not state how old the fuel is and whether or not it was ever opened. Glow fuel can last for many years if it is completely sealed and stored at room temperature in a dark place. However, the slightest compromise of the seal can allow moisture to be absorbed into the methanol in the fuel, or allow the nitromethane and methanol to evaporate. I have used tightly sealed (previously unopened) glow fuel that was over 10 years old and it still worked fine. I have also seen fuel less than a year old that was useless due to absorbed moisture and contents evaporation. If you stored the fuel in a jug with a cap having a fuel dispensing hose stuck in the top, then the answer is almost certainly spoiled fuel, especially if it was stored in non-climate controlled space. Store it in a barn and the daily temperature variations will pressurize and depressurized the container, causing moisture laden air to be sucked into and forced out of the jug, causing moisture contamination. Bad fuel can cause poor idle, loss of top end power and flameouts when the glow plug is disconnected. If it is less than 10 years old and never opened, then it is probably worth giving it a try, especially considering that fuel currently goes for $25 to $35 per gallon depending on location, shipping costs and nitro content. The only way to know is to try it.

mgnostic

You are on target with the fresh batteries. You didn't mention battery chemistry but Nimh is a definite upgrade over Nicads if that is what is in the radio if the radio is that old. LLRC pretty much identified the issues with old glow fuel. I just cracked the seal on an old jug of fuel and it ran great but the only way to know for sure is to gas up the plane and run the engine.

LLRCFlyer

Another thing to check after many years sitting idle are the servos and wiring. Check all wiring to make sure the insulation has not turned brittle.. Also cycle each servo 100 times over its full range of travel to verify it is not gritty and does not stop, jitter, surge or pulse due to dirty brushes or a dirty potentiometer.

piper_chuck

My Feedback: (12)

Thanks. Yup, the radio is old enough that the transmitter battery is nicad. It's a Futaba 7C. The new battery is a 2000 mah nimh. For the plane I bought 5 cell 2000 mah nimh packs. I have the transmitter battery going through a cycler to make sure it's good.

piper_chuck

My Feedback: (12)

Thanks. The fuel is in a sealed jug and the color looks good. I've had it in my workshop, which is part of the house, all these years. Not so with the half full jug thats on my flight box. It is a really nasty looking dark color. I'll throw out the nasty stuff and give the fuel in the sealed jug a try at home.

The props are brand new and have also been in the shop. I'll check them over and replace the one that's on the plane.

piper_chuck

My Feedback: (12)

I've cycled the servos quite a few times and they're working well. I'll chek the insulation as well. Your response also got me thinking I should spray electronic contact cleaner on all the connectors.

mgnostic

Yeah, if the fuel is starting to turn brown the oil has probably started to polymerize. Given enough time and exposure to oxygen almost any oil will turn to varnish. As for props the ones you mainly have to be careful with are the old fashioned white nylon props. They dry out and get brittle. Back in the day people used to boil them to restore their proper moisture content but by now I wouldn't use one for anything but display. I would say the same goes for novelty props such as clear plastic.

piper_chuck

My Feedback: (12)

I remember the white nylon props and the boil recommendation. IIRC they were from Topflite and had red lettering. I probably still have a few lying around somewhere. The ones in question are grey APC props.