www.abellhobby.com

Abell RC 25% X260 
(IN STOCK!)

The New Color Scheme on the 70" Extra 260 is an eye catcher to say the least, but looks aren't everything, this big bird flies as good as it looks due to its generous wing area and light wing loading. Weather you power it with a glow engine, gas engine or even a brushless out runner setup you will be pleased with the stunning looks and awesome performance. The X260 excels in both precision and 3D flight! Rock solid harriers, straight and true knife edge's, crisp snap rolls, axial rolls and breath taking rollers!

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Note, the Green color scheme is temporarily unavailable

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• Specs:
  WING SPAN: 70"
  WING AREA: 972sq in
  LENGTH: 67" without spinner
  FLYING WEIGHT: 8.6-9.5lbs
  ENGINE: 20-32cc gas / 1.20-1.50 Glow 
  RADIO: 4CH / 5-6 Servos (Recomended; 80 inch ounce torque, metal gear)
  

Woohoo! The Prototype arrived today and I must say that it looks awesome! Thanks to JohnW, the design contest winner. I have a few days off coming up, I think I will be in the garage all weekend, be sure to check back to this thread, I will be taking pictures to document how easily this plane goes together, and who knows, maybe the weather will allow a flight or two in the near future. All I know is that I cant wait to get started on this thing. I plan to use the CRRC 26cc gas engine for this plane, it turns a XOAR 18X6 at 7500rpm right out of the box so there should be plenty of power for the 3D stuff!

Before we get started here I would like to mention that this thread is not intended to be a replacement for the instruction manual that comes with the AbellRC 70" 26cc Extra 260. I am not perfect so you may find mistakes, bad grammar, misspelled words, blurry pictures and maybe even a beer can or two in the background of some pictures. I don't claim to know everything but I have been in this hobby for 21 years now and just maybe some of you can find some of the information helpful.

OK! Got everything out of the box. Usualy when I get a new plane I automaticly plan on getting out the sealing iron and heat gun, I hate that! But not this time, covering is as tight as a drum, no wrinkles, no loose edges, very cool. The included hardware looks very useable, Hangar 9 style stuff. Another thing that pleased me is the color match of the paint on the cowl and wheel pants, very close. Carbon Fiber wing tube Aluminum LG











I thought that it would be best to plot, drill and install the control horn screws for the ailerons before glueing the hinges. You can see in the pics below where to drill the holes for the control horn screws (make sure the holes go through the hardpoint built into the ailerons), I used a 9/64" drill bit. I used a drill press to ensure that the holes were aligned properly, I also used a small block of wood to shim up the trailing edge of the aileron, this helps keep the control horn screw square to the wing. After drilling the holes, install the two longer screws into the ailerons, then install the nuts as shown. Tighten the nuts snug, do not over tighten. (dont forget to use some thread lock). If you use tape as I did in the pictures, make sure that it is the low tack type, this will help insure that you dont pull the covering off when you remove the tape.








Install Servos in the wings, I am using Hitec HS-965MG servos in the wings, they have great torque, speed and they don't cost much! First I manually centered the servo arms onto the servo making sure that the servo arm had equal amounts of travel in both directions from center. I then pre-drilled the servo mounting screw holes in the wing with a 1/16" drill bit to accept the servo mounting screws that come with the Hitec Servos. Mount the servos into the wing as shown, then assemble the push rod linkages. Drill out the outermost hole in the servo arm with a 7/64" drill bit and then install the linkage as shown, adjust the length of the linkage so that the servo arm is centered and the aileron is in the neutral / centered position as shown.






















Time for the tail feathers! Got a lot of pictures for this part, I feel that this is a very important part. First I slid the horizontal stabilizer into the fuselage. The first thing I look for here is to see how the horizontal stab lines up with the main wing / wing tube. Once again I am pleasantly surprised, the stab lines up perfectly with the main wing tube as you can see in the picture. It is not unusual to have to do some sanding and fitting to get these things to line up with each other. Next I centered and squared the horizontal stabilizer in the fuselage by measuring one side against the other until I was satisfied that the stab was where it needed to be and used an ink pen to trace the shape of the fuselage onto the horizontal stabilizer then removed it from the fuselage. Using the outline drawn on the stabilizer as a guide, I cut the covering about 1/8" inside the line and removed it. (Be very very careful here, you must only cut the covering, the knife or razor blade must not cut into the wood! if it does I can almost guarantee that it will cause an in flight failure!)














I first positioned the elevator joiner in the fuselage as shown and then re installed the horizontal stab into the fuselage and re positioned it using the previously drawn lines as a guide and then erased the ink lines using a small bit of acetone and paper towel. Then using thin CA I glued the bottom horizontal stab to the fuselage. You can see in the picture below that the fuselage was positioned upside down and at an angle so that the glue would run into the joint. Then the fuselage was tilted the opposite direction to glue the other side. Repeat this gluing technique a couple more times, just to make sure the glue is filling the joint and then a final time with medium CA to fill any gaps that the thin CA could not. Make sure to let the glue dry before turning the fuselage over to its upright position so that the glue doesn't run down the  side of the fuselage on the covering.
































Pre-drilled the the holes for the Hitec Servo Screws with a 1/16" drill bit, installed the servos, I used a 24" Extension for the rudder and an 18" extension for the elevator, note the orientation of the output shafts on the servos, the output shaft on the rudder servo is towards the tail so that the rudder linkages can reach the rudder. Also make note of routing of the wires. The two bottom pictures show the servo extension safety clip, these things work very good and they dont cost much either! 








Trial fit the elevator halves making sure that the elevator joiner fits properly, insert the hinges with stick pins to hold them in place, once you are satisfied with the fit mix up some 15 minute epoxy and work it into the hole that accepts the elevator joiner wire, wipe off any excess epoxy, we don't want to glue the elevator to the stab! slide the elevator halves into place. (push the elevator  halves tightly up against the horizontal stabilizer) DO NOT GLUE THE HINGES YET Now use a small piece of low tack masking tape to hold the elevator halves in position while the epoxy cures.










Once the epoxy has dried on the elevator joiners, center and align the elevator halves, set the hinge gap so that you get adequate throws up and down, I like 45 degrees. When satisfied with the alignment of the elevator halves apply CA Hinge glue to the hinges using the same technique as with the ailerons. make sure to only do one elevator half at a time. Next is the tail wheel assembly, slide the shaft lock / wheel collar and tail wheel bracket onto the the tail wheel wire and then make a 90 degree bend in the wire as shown. (don't make the the part that fits into the rudder any longer than what is shown in the picture or the rudder wont fit properly, in fact it might be best to make it a little shorter than what is shown in the picture) Glue the tail wheel assembly to the rudder with 15 minute epoxy making sure not to get any glue into the tail wheel bracket. Now insert the hinges into the rudder as shown. (This kit came with an extra CA hinge so I doubled them up at the bottom of the rudder for extra support for the tail wheel) install the rudder assembly onto the vertical stab and fuselage, do not glue the hinges yet. Fasten the tail wheel bracket to the fuselage bottom, pre drill the holes for the screws using a 1/16" drill bit. Now align the rudder for proper fit making sure that the rudder moves freely without binding or rubbing on the top of the vertical stab. Once you are satisfied with the alignment of the rudder, glue the rudder hinges.








Next I marked the locations of the rudder and elevator control horn screw and drilled a hole at each location using a 9/64" drill bit. The tolerances between the elevator and the rudder control horns are close so use the pictures as a guide but try to plan ahead to avoid clearance problems, make adjustments to the location of the holes if needed. The covering needs to be removed around the area shown so that the control horn doublers can be glued to the wood of the rudder and elevators. The control horn screw for the rudder will need to be cut off so that it doesn't interfere with the elevator.  Install the control horn screws and nuts as shown, be sure to use thread lock here.














Center the servos and install servo arms and linkage.










OK, wing, rudder and elevator servos are in, cleaned up a little, put some tools away so that I wouldn't trip over them anymore. The Engine will be the next task but I couldn't help myself! I just had to mock up the 70" 26cc ~ 30cc Extra 260 so I could get a good look at her, I really like this color scheme! cant wait to get the decals on it, sorry for the blurry pictures but they will have to do for now.














To mark the hole locations on the firewall for mounting the engine, draw a horizontal line 1&1/8" above the existing horizontal line that has been burned into the wood, then draw another horizontal line 15/16" below the existing burned line. Now measure 1&1/8" from the vertical centerline and make a mark on the horizontal lines just drawn as shown. Drill a 1/4" hole at each intersecting line. I found that the threaded part of the blind nuts provided with the CRRC g26i protruded to far through the firewall and would not allow the standoffs to tighten against the firewall so I doubled the thickness using some 1/4" hardwood.










I forgot to mention that you need to use thread lock on the motor mount screws.

The next thing is the tedious task of fitting and mounting the cowl. First remove the spark plug from the engine, then slide on the cowl, it wont go all the way on but slide it into position to the point that it makes contact with the cylinder head. then reach in and trace the shape of the head onto the inside of the cowl, this will give you a starting point for removing material so that the cylinder will clear the cowl, remove a little bit of material at a time, checking the fit each time until the cowl fits where you want it. You can see in the pictures that I used a spinner to help make sure the cowl was aligned properly. This spinner comes with all the stuff needed to mount it to the front of the CRRC 26cc Engine. Once happy with the fit and alignment of the cowl, I marked its position on the fuselage. I also found it necessary to cut part of the velocity stack off so it would clear the cowl. Do not worry about cutting the cowl for the muffler yet, that will come later.














Remove the spinner and cowl. Make three marks on each side of the fuselage as shown, the location of the marks are a little different from one side to the other due to the right thrust that is built into the fire wall. These marks represent the location of the cowl mounting screws. You can pre drill the holes to accept the the screws or you can use my favorite cowl mounting method in the next post.






Drill a 5/32" hole at each marked location, then install the Ohio #4 Screw anchor into each hole, position the anchor so that it sicks out a little bit from the outer surface of the fuselage, Glue in place with thin CA and then again with medium CA.








cut a piece of printer paper in half, lengthwise and tape it to each side of the fuselage as shown, try to keep the tape on the white covering so that it doesn't peel the blue or green covering up when you remove the tape. Make sure the paper is lying flat, then use a small drill bit and poke a hole through the paper as shown. Do this on both side of the fuselage. Now slide the cowl back on and align it with the marks made earlier on the sides of the fuselage. Now with the plane on its side, make sure that the paper is lying flat as before, put the point of an ink marker into each hole in the paper and pushing the paper against the cowl. Walla! Now you have the exact location of the holes that need to be drilled in the cowl








Carefully drill the holes in the cowl so that they are slightly larger than the red plastic screw anchors and I do mean carefully, the fiberglass can easily tear or rip if if the drill bit catches it wrong, I start with a 1/16" drill bit and work my way up but still, go slow. After the holes are drilled slide the cowl into position so that the holes in the cowl fit over / around the red screw anchors. Cut some small washers from some fuel tubing and install onto the #4 sheet metal screws. Slowly screw the screws into the anchors working the screw in and out, advancing the screw 1/2 of a turn each time, this builds a little heat into the screw anchor to help form the threads in the plastic. Now we have clean yet effective cowl mounting system where the metal screw is isolated from the cowl by the fuel tubing washer and the screw anchor. I have been using this technique for years, even on my 42%ers, I never loose a cowl screw in flight due to the friction of the screw in the anchor.








Use the printer paper trick to locate the hole for the exhaust. I chose to shorten the exhaust outlet, you don't have to do this but the hole in the cowl will need to be larger to create the clearance needed to put the cowl on. I also removed the block of wood on top that was meant for attaching the cowl because the cowl was hanging up on it, didn't need it anyway.  Made a relief for the front part of the muffler and cut a large area on the bottom rear portion of the cowl for the air to escape the cowling, this really helps to increase airflow over the cooling fins on the CRRC gf26i.












Throttle servo is in!
I shimmed the front of the servo up with a piece of 1/2" hardwood to help get better alignment with the throttle lever on the carb. I tried to make use of the white plastic clevis that comes with the kit but then decided a 2-56 Dubro Ball Link would do a better job. Had to remove the throttle lever from the carb to get the tiny little nut on the back side of it and then applied thread lock to the threads of the screw when the arm was reinstalled on the carb. Also removed the idle stop screw, the throttle trim on the transmitter will control the idle speed of the engine and with the screw removed, the engined can now be shut off with the tx as well.






Ignition is installed, gettn closer!






Fuel Tank install is pretty basic, The clunk line and stopper that comes with the abellrc 70" 26cc Extra 260 is good for both glow fuel and gasoline. Normally I use a two line setup but in this case you will need to go with the three line setup because the stopper has three holes in it already. No big deal, the three line setup works just fine. Make sure to clamp the clunk line to the aluminum tubing, I simply twisted some wire around the fuel line to hold it in place. Because we are using a gas engine with a Walbro carb that actually pumps the fuel from the tank, tank placement is not as critical as it is with a nitro engine so I built and installed a fuel tank platform just under the wing tube, with the fuel tank this close to the balance point of the plane it should balance the same whether the fuel tank is full or empty.








Fuel tank is in! Used a little weather striping foam on the platform to help dampen any vibration that might foam the fuel in the fuel tank. See the fuel filter? Fuel filters are GOOD! (if you check them every now and then) I picked up some rubber grommets and installed them into the bottom of the fuselage to retain the fuel tank vent line and fill line. Note the extra length  provided on the fill line (the blue one) this allows some slack so it can be pulled out when fueling the airplane and then pushed back in before flight. I used a little CA glue to hold the vent line in place (the yellow one) I use different colors of fuel line  on the vent and fuel line so that I can know witch one to put the fuel into! The line with the  Aluminum plug in it (bottom right of the picture) is the fill line.






I installed the cowl, spark plug, prop, spinner and wings (had to do a little filing on the spinner so it would fit the large XOAR 18 X 6 Prop) Before installing the batteries and switches I checked to see where the 70" Extra 260 was currently balanced vs where it should balance. Instructions in the manual do a god job of telling you how to find the balance point of the 260 but there is an easier way, just pick up the plane by the wing tube (with the plane fully assembled minus the canopy). This 260 is nose heavy so now I placed the batteries, switches and receiver in the fuselage and checked the balance again, and move the stuff as necessary to get the plane to balance on the wing tube, in this case the batteries (one Desire Power 2000mAh 6v for the receiver and one Desire Power 2000mAh 4.8v for the ignition) ended up at the rear of the canopy hatch.

Normally I try to keep the ignition and any of its components as far away from any radio component as possible but in this case I am using a Spektrum 2.4 DX7 radio system so the normal things that interfere with FM don't interfere with 2.4, I have only had one thing to knowledge that caused a 2.4 system to go nutty and that was a loose spark plug cap.




















Radio gear is in place, used two 6" extensions for the ailerons and 12" extensions for the ignition and throttle servo. Note the servo extension safety clips and the wire keeps, the less the wires can move around during flight the better, keeps things from working loose!  I guess that I am a little "Old School" it just seems really weird not having to fish a long antenna wire down the tail portion of the fuselage.




Programming is next, setting endpoints, travel limits and sub trims, follow the instructions that came with your radio for this. Make sure to remove the servo arms from the servos the first time you power up  the receiver, set all sub trims to zero and end points to 100%, then install the servo arms back on the servos and adjust the sub trims and end points accordingly. My favorite starting setup for an aerobatic bird like this is...

Ailerons  35 degrees High rate with 60~70% expo
Rudder   40 degrees High rate with 60~70% expo
Elevator 40 degrees High rate with 60~70% expo

then I set low rates at 50% of the high rates with little to no expo

Thats just what I like, doesn't mean you have to do it the same way.

When I first unpacked the Extra 260 there wasn't a wrinkle in the covering but as time went on a few did develop on the turtle deck and below the wings. Also, when I was wiping the airframe down to prepare it for decals my rag caught the point of the blue swoops on each wing and peeled back the top clear part of the covering separating it from the color,  It was easily repaired though by carefully placing it back into position and going over it with a covering iron on low heat. The wrinkles in the turtle deck and under the wing were also easily ironed out with the iron on low heat. Make sure you use low heat, start very low and increase the temperature only if you absolutely have to and most of all take your time and don't rush it.






Cut out the decals and stuck them on!  I sprayed the area where the decals were to be placed with a mild solution of 409 and water, this enables me to slide the decal on the covering until it is exactly where I want it, then slowly work the fluid and air pockets out from under the decal by using a credit card as a squeegee. This is kind of a time consuming procedure but it pays off in the end.

I also put a piece of clear tape along the leading edge of each wing to ensure that the covering would not come loose at the seems.












SWEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEET!!!




After I took the 70" 25% Extra 260 off of the scale and placed her back on the work table I suddenly realized that I had forgotten to provide a way to access the choke for the carburetor on the CRRC GF26i
The CRRC carb has a unique choke setup, once the choke is shut and the carb butterfly is in the closed position, the choke locks into the shut or choked position and is then released once the throttle is advanced. This is kinda cool! All I needed to do was to provide a way to apply/close the choke. To do this I used another Dubro 2-56 Ball Link and fastened it to the choke lever along with a short piece of 2-56 threaded rod as shown in the pictures below. If you look closely you can see that the outer end of the ball link has been cut off, this was done so that the ball link would clear the cowl when the choke lever is pulled out. Next I used the printer paper trick to mark the location where the 2-56 threaded rod would exit the cowl and then carefully drilled the hole in the cowl. I slid a piece of fuel tubing over the threaded rod to protect the cowling and then used the plastic clevis that was intended for the throttle linkage as choke handle.

I first tried to use a rubber grommet to protect the cowl but after a little testing the grommet failed. The fuel tubing over the threaded rod works way better!












Flew it yesterday!, got two flights on it, everything went great! plenty of power with the CRRC 26cc up front swinging a XOAR 18x6 @ 7100 RPM, (it will turn it up to 7500 but keeping it a little rich for the first few flights) It was kinda spur of the moment, looked outside and the weather was good, 48 degrees with a 2mph breeze, the only bad thing was my video camera wasn't as prepared as the X260 was so no video this time, will be sure to get some footage the next time the weather breaks. The plane flew awesome, balance was perfect, 2 clicks of down trim and 1 click of right aileron was all it needed. I was very impressed with the CRRC, way more power that the SPE26, it jerked the 260 right of the ground, hovered at about 3/4 throttle, once the engine is dialed in and on Ams oil I expect to be hovering at 1/2~5/8 throttle. Knife edge was straight and true, I did need just a hair of up though probably due to the 2 clicks of down elevator. Harriers were solid, Water falls, flat spins, rollers, this thing does it all man and landings were so easy it felt like I was flying my 42% Dalton! Here is the Video!     http://www.youtube.com/watch?v=HuwbGfgVlUQ