Well after a very successful maiden last week, I had a very unsuccessful third flight today. After about 2 minutes in the air this morning, the EDF quit in flight and I ended up “lawn-darting” her in.
The battery had plenty of charge left so it wasn’t a brown out due to a low battery. I could still move the control surfaces, so I know it wasn’t due to loss of radio signal. I assumed either the motor fried or something went wrong with the ESC.
After getting her home and doing a bit of disassembly, I discovered that the motor to ESC wires had come loose!!! How does this happen in flight? They must have been loose from the factory.
Unfortunately, the connection is hidden when the fan unit is installed and I never thought to remove the fan to check the connections. After-all, I never had anything go wrong on bench tests before her first flight. It just never occurred to me to even think about checking the ESC connections.
Well lesson learned! From now on, I will be double-checking all connections and mechanical joints on any ARF I happen to buy.
To make matters worse, I had a new 4S 3000 mAh pack (only used once before) in the plane that got a bit crunched too. The pack is deformed and feels a bit squishy (not like its puffed), so I think I am going to trash the pack. It’s not worth the $37 to risk fire with a physically damaged pack.
I sent pictures and a description of what happened to Motion RC (where I bought the plane). Maybe they will take pity on me and help me out here. If not, I can pick up a new fuselage for $50 and get her back in the air without too much trouble.
One of my projects from last summer was an attempt at a foamy scratch building with a Fan Trainer EDF built from Dollar Tree foam board. I patterned it after the 150% scaled up version of the plans found in this build thread: http://www.rcgroups.com/forums/showthread.php?t=426281.
This was my first attempt at both EDF and at building with foam. The building process went well and I kind of enjoyed working with foam.
The total investment in foam was about $5 (including scrap and re-work). I powered it with a Detrum 70mm Fan combo from HobbyPartz.com which includes the fan, motor, ESC, and servos for under $50. All in, with batteries, and a 4 channel receiver, total investment was under $100.
Unfortunately, it did not survive its maiden flight. The wings were simply not stiff enough and fluttered badly. Apply enough power to keep the plane flying, and the wings flapped like a hummingbird. Back off the power, and there was virtually no control. I ended up lawn-darting and disintegrating everything from the wings forward (sorry, no picture of the damage).
Oh well, nothing ventured nothing gained. The electronics and fan escaped unscathed, so the total loss was under $10 (and a little bit of pride). I have a few ideas for how to use the fan and other bits from this attempt in a new creation!
Well it has been over a year since my last post. I have not given up on the hobby, but I did get lazy about posting! I have not worked on my P-47 since last year. I was traveling extensively for work last year and got sidetracked by some home remodeling projects, so it was hard to find a lot of build time. I did manage to put together a StevensAero RV-4 which was a fun little park flyer.
Unfortunately, I am sad to say that I had my first real outright destroy the plane crash with her yesterday evening. It was due to pilot error, plane and simple. I was getting a little too fancy for myself a little too close to the ground. The plane got into a spin, and I did not have enough altitude to recover. It’s hard to see in the picture, but the forward half the fuselage is just a bunch of broken bits held together by covering.
In a way, it actually feels like a bit of a relief to have that first total wreck behind me. I have been so afraid of crashing that I often hold myself back and end up just boring holes in the sky flying a simple pattern. I did learn a lesson about keeping enough space between my plane and the ground when I am trying out something new though!