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I finally got the subfins on, with a minor misalignment, and was ready to hinge the rudders and elevons. But first, I must confess to having a very strong dislike for hinging. So far I have either mostly bought already hinged ARFs, or already built kits. I have hinged one ARF that used epoxy hinges and it was a disaster. The one kit I built I used iron on hinges -- no slotting! So it was with more than a little angst that I proceeded to hinge the control surfaces of my Delta Vortex ARF. I was going to further complicate the task by hinging the bottom of the rudders to the subfins. This meant I had to correct the misaligned subfin hinge slot so it wouldn't bind. I also substituted SIG easy hinges for the ones supplied with the ARF. Someone told me to stick a pin through the center of the hinge. I assume this would keep you from pushing all of the hinge into one side or the other and keep an equal amount on both sides. After cutting the slots in the rudders and subfins and sticking the pins through the hinges I got everything hooked up. Then I put three drops of thin CA onto each hinge after pushing the control in tight and deflecting it in each direction to expose the hinge. Much to my surprise -- it worked! Then I saw that I forgot to push the rudders up tight against the top of the fin slot. There is now an 1/8" gap at the top of each rudder. Oh well, at least they didn't pull out when tugged on. Next I turned my attention to hinging the elevons. I found that the slots in the wing were not deep enough for the easy hinges. After a little "enlarging" and "deepening" with my trusty #11 these too were ready for thin CA. After three drops on each side of each hinge I now have the elevons hinged. And that completes the airframe!

The final weight for the airframe sans hatches and landing gear is 3 lbs. 8 oz.! I am starting to worry that my O.S. .91 FX is going to be way too much power!

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Since last I posted I have installed all servos, the elevon and rudder push rods, the control horns on the rudders and elevons, the landing gear and the engine. I have also installed the receiver so I can attempt to program all of the mixes. But that's a whole 'nuther story. For elevon servos I am using Hitec 605BB UltraTorque. These servos have more than the recommended amount of torque. They are a littel slow, but that should be okay. All other servos are standard, non ball bearing type. I thought about using micro servos for the throttle and nose wheel steering in an attempt to save weight. But the cost was more than my wife could bear and these servos are not that far forward of the CG anyway...

I built the push rods from the 4-40 hardware that was included in the hardware upgrade kit that Bruce sells. This is my first time using this size pushrods, but everything worked out fine. I also used the replacement control horns from the hardware upgrade as well. They look just like the ones that came with my SIG Somethin' Extra.

The hardware upgrade kit also came with new landing gear. The best part of this is the new main gear legs turn out instead of in and that adds about 4 inches to the track width. It also looks much better with the axles turned out. The new nose gear comes with a bearing that is mounted behind the firewall. This moves that weight back a little and saves 1/2 oz. off of the engine mount since you don't need the nose wheel bearing pieces.

Mounting my O.S. .91FX was very simple and straight forward. The hardware upgrade came with new 6-32 blind nuts to replace the 4mm ones in the firewall. I really wanted to replace the metric hardware, but I could not pry those metric blind nuts out. They are really in there so I left 'em and used 4mm cap screws to attach the engine mount. Once the engine mount was in and the proper width was set the back of the spinner was set to 4.5" forward of the fire wall and the mounting holes were marked using my dead center tool. This is one handy tool that I use for a lot of different tasks. 6-32 holes were then drilled and tapped and the engine was mounted.

I have also sealed the elevon hinge line using strips of covering. I have also covered the seam where the trailing edge extender and the wing tips are attached. It looks much better and will keep crud from getting in those seams.

Things are really starting to move along now and I should be ready to fly before too much longer.

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The final tasks remaing were to connect the nose wheel and throttle; mount the fuel tank, cowling, receiver, and spinner; finish programming the radio; and set the CG and control throws.

I used the hardware upgrade supplied cable and nylon tubing to connect the throttle and nose wheel steering. I needed to drill my own hole in the firewall to get the cable to exit some where near the carburator on my O.S. .91FX. Both of these connections were time consuming. The biggest problem was tinning the ends of the cables where they go into EZ connectors. After much hassle I finally figured out the trick of using the soldering iron tip on my torch instead of the flame...

Next came the cowling. This was much easier than I expected and by using the clear dummy cowling supplied in the kit I soon had this task completed. I used a carbide cutter on the lowest speed my B&D Wizard can turn to rough cut the openings. I switched to my sanding drum to get the exact shape I wanted. It came out rather nicely without any chipping at all. I also attached it with four 2-56 cap head screws and blinds nuts instead of wood screws. I really prefer the positive locating characteristics of a screw and blind nut on my cowlings.

Finally I was able to put in the fuel tank. Since I know the .91FX will consume more fuel I replaced the 360 CC tank from the ARF kit with a 16 oz. Dubro. Since this is the recommended tank for the kit it fit in very nicely. I had to drill my own exit holes for the supply and vent lines. This left that large hole in the middle of the firewall un-used so I ironed a piece of covering over it. I also used some foam to pad the tank and hold it in. I used more foam to pack it in tightly when the hatch is closed. But now I am think that I should have added the glued in supports. 16 oz. of fuel might not want to stay put with out a little more restraining... I also replaced the 3mm blind nut that holds the tank hatch on with a 6-32.

Once all engine connections were made and the cowling installed I turned to the prop and spinner. I had intended to use a yellow 3 inch CGM spinner that I had lying around (I like the contrast with the blue), but the engine ended up too far aft for this spinner. Since my wife hated the yellow I decided to use the blue one from the ARF kit. My trusty sanding drum soon had it fitting my 15X8 APC prop.

Last were control throws and the CG. Control throws were easy -- just remember to measure the rudders at the base as they are slanted. The CG required all of the lead I had on and to get it just a little forward of the forward mark. I have a little less than 4 oz. on hand and think another 1/4 to 1/2 is needed. After I get more lead I will try adding some to the wigtip opposite the muffler to get lateral balance and kill two birds with one stone.

All in all I am very happy with the way this ARF went together. I am expecting it to fly just as well. The weather here is forcast to be good at the end of the week and I am planning on taking Thursday and Friday off from work. The maiden flight should happen then.