RCU Forums - View Single Post - Just when you think you have it all under control...
Old 06-17-2012, 06:38 PM
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acdii
 
Join Date: Jan 2011
Location: Capron, IL
Posts: 10,000
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Default Just when you think you have it all under control...

Your plane tells you otherwise.

Plane: Lets see what can I do to really make my pilot cringe....

Today I flew my Dewey with a smaller prop on the DLE20, I put a 15X6 on it, and while I had less thrust, It still seemed to work OK, needed higher RPMs to fly it as before with the 16X8, and the max RPMs were 9200, so not too bad, however, Inoticed the plane felt a little off, it wasn't responding to the controls like it did before, Ionly had something like 4-5 flights on it, and it was pretty predictable, but not today. Ihad done a flight line pass downwind, about 50' up, and was going to do a turn around and bring it in for a landing since it just didn't feel right, and as I pulled up to get a little altitude it pitched up and started to roll, I corrected the roll and tried to level out, gave it a bit more throttle to prevent a stall and it really started to roll and yaw, and got really goofy, so I chopped throttle and tried to straighten it out, had it heading back my way, then the nose dropped, gave it a bit of throttle, it veered and started to roll, chopped throttle and tried to keep it level as long as I could but I just didnt have even sky, plowed the field with it. Ifound it in the corn field nose slightly to the north west, last I saw it was heading southwest. The wing was still attached, but the back struts had broken off, and the landing gear had sheared off. It landed level though, no part of the wings hit dirt.

Plane is easily repaired, a couple hours, a sheet of 3/16" balsa, some epoxy and new covering and it will be good to go. So post crash forensics has found the pushrod for the rudder had come apart, I had lost all rudder control and since the part that had come off was near the servo, the long pushrod was acting as an anchor, when the rudder moved to one side, it stayed there. When I applied aileron, the force of rolling must have forced the rudder to the other side and stuck, until I tried to correct, so basically the rudder was swinging back and forth every time I tried to level out. If I had enough altitude, I might have been able to get it down, but cross winds were picking up, and without rudder, the landing may have been even worse than what it was.

The pushrods are aluminum tubes with the wire rod bent at a 90* and the end stuck through a hole, then a plastic bullet is glued in to secure it, this is the piece that failed, separated, and fell out of the tube. Ithink the DLE 20 may have contributed to the failure due to its enormous torque and vibrations. Too much engine for the plane. Going to replace it with a Magnum .91 FS.

Ihad given some thought to redesigning the plane, making it maybe a mid wing instead of a parasol plane, but the wing and fuse are not damaged enough to warrant a makeover. The piece that holds the gear can be glued back in, along with most of the pieces of balsa skin that coverd it. Straighten out the wires that support the wing, and shoot some epoxy down inside to secure them where they came loose, replace both pushrods with something less likely to come apart, and the fuse is fixed.

The wing busted at the back where the hold downs for the rear struts attach to the ribs, and the trailing edge busted off to #2 ribs, so 3/16" planks and some epoxy and they will be secured, then some new covering and the plane will be whole again.

Worst part about the whole ordeal, Ibusted my brand new prop.
Since I am going to put a FS glow on it, I removed the second battery pack, ignition, opto kill, and fuel tank. Ihave a regular tank for glow for it and will put that in,and probably have to relocate the throttle linkage for the new motor. Maybe with it being a little less nose heavy and with the right prop, it might just fly better. That DLE fit fine, but it is just too much power for this plane. It flew OK with a 16X8, but landings sucked, if you didn't time flaring just right, the prop hit the ground.