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Aug 30, 2010
Repairs...
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Prop & Spinner repair
After my ugly landing at the end of my maiden flight last year, I was fortunate that the only real damage to "Black 3" was a broken prop and spinner. So one of my first repair steps was to order a new Zinger 20 x 8-14 prop, paint and balance it. I found a replacement scale spinner at DJ Aerotech that worked out perfect. It's fiberglass and approximately 4 inches wide across the backplate.
After using a contour gauge on the Zinger prop to define the contour of the prop at the point where it exits the spinner, I put wide masking tape on the sides of the spinner and transfered the shape from the contour gauge over to the tape with a marker. The tape gives you something to draw on but more importantly it helps keep the fiberglass from chipping or splintering when you grind out the contour with a dremel tool, which obviously was the next step.
Lastly, sanding and painting it put me back in business with a finished prop and spinner... just like new. |
Fuel Tank issues
After having a gas-rated rubber stopper in my original Sullivan fuel tank simply dissolve over the winter, I replaced the entire tank with a DuBro brand tank instead. Then after only one flight, the DuBro stopper's plastic outer cap broke/split out, making that tank no good as well. The tank itself was OK, so I just went out and bought an Ernst heavy duty stopper and cap setup like the one shown at right. The photo shows the glow stopper, but it also comes with a gas-rated stopper which is the one I used. After replacing the aging fuel lines (just to be safe), I replumbed the tank and installed it back in the plane... good to go. |
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Repairs...
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Upgrading the Main Gear Springs
The original springs that came in my Shindin main gear were really intended for a slightly lighter plane than what mine ended up being, so I felt that they really weren't optimum for the job. They were rated for about 13 pounds each and my plane weighed roughly 27 pounds so each spring was just over it's max rated load.
Lenny at Shindin Machine helped me to locate replacement springs from MSC Direct, where you can buy a variety of color-coded springs at different strengths. I bought a few different ones to test and ultimately went with the "Blue" heavy duty springs (part #07660319) that were rated for 28 pounds each, for a total of 56 pounds... far more than the weight of my FW190.
Removing the springs was easy, just remove the main set screw and the lower strut & springs come right out as shown at left. Measuring the stock springs and struts told me they needed to be 2 inches long and had to fit a 3/8" inside diameter shaft.
To install the new heavy duty springs, just reverse the process. Slide the new springs into the struts, then slide the lower strut piston into the upper strut. Squeeze/compress the lower strut in until you can see the hole for the set screw. Now just thread the set screw back in place and tighten. That's it... new heavy duty springs installed. The plane sets much more level all the time now and later taxi and flight test proved that these springs were perfect for the job. |
Updating the Receiver to 2.4ghz
I decided to make the switch from FM/PCM radio gear to 2.4ghz gear this year, so I bought a new Futaba T10CAG Transmitter which came with a 14 channel 2.4ghz receiver as well. So, I decided that this was the RX that I wanted to put in my FW190.
As you can see at right, the 2.4ghz RX is way smaller than the standard PCM RX, and by swapping out the original PCM RX and Power Expander board, I was able to go from 3.9 ounces or RX gear to 0.7 ounces, thereby removing over 3 ounces of weight from a spot that was well behind the planes CG balance point!
I had no complaints or issues with any of the original gear, I simply wanted to switch to 2.4ghz technology and try to shave a little weight off... especially behind the CG. The new RX works great and I can notice a slight difference in the way the plane flys now. |
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2nd Flight - huge success!
After spending a good bit of time doing the above listed repairs, tweaking/upgrading, and quite a bit of Gremlin chasing, I finally got enough stick time in to brave taking up Black 3 again this weekend and it was 100% successful!
Take off was much better this time, and it once again flew like a champ the entire flight (man I love flying this plane)... then I went on to flying circuits with flaps down to test them out and after about 3 low dirty passes down the runway I felt pretty ready to try the landing again.
So, I lined her up, started decreasing speed and watched the gradual descent to the runway where I dropped smoothly onto her mains, rolled out about 15 feet then let the tail come down. I used up most of the runway but it was smooth as can be with no problems whatsoever... wooohooo!
I noticed that dropping the gear really pulled the nose down a bit since they have so much forward rake to them, but deploying flaps offset it somewhat. I still had to keep feathering a little up elevator into it to keep the nose up when slowing down with full flaps but it was not a problem at all. I was AMAZED at how stable it flew with full flaps and gear down. Dirty circuits were almost no different than flying clean except they were just slower.
It had no mushy/squirrely behavior at very low speeds with flaps and maintained a great deal of control surface authority even at those low speeds... very pleasantly surprised. Trying to land without flaps last year was definitely the main problem and I am no longer afraid of trying it again now. The heavier springs I put in the Oleo struts this Winter made a big difference too... they are perfect now. Also, I think the decreased latency with the new 2.4ghz radio was an added plus.
The bad news is we didn't have any cameras at the field so I have no video or pics (this time)
Until next time... Cheers!
Tom
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