These pages will show the building of my own Comp-ARF Extra 2x2 over the coming weeks. I'm not the world's fastest builder nor do I have a huge amount of time to build so please bear with me regarding the updates to these pages!!
Here is the first step - opening the box and checking out the good stuff in it! As with all the Comp-ARF kits, all the moulds are superb quality and very light. Here's everything you get in the box and the component weights....
So, that's a total weight of 738g + 100g + 72g + 474g + 478g + 122g + 118g + 96g + 208g + 20g + 158g + 52g + 500g = 3.14Kg or 7lbs
The first job is to fit the undercarriage and tailwheel. I started by drilling 4mm holes through the carbon legs using the factory marked indentations. Next I applied a piece of masking tape to the fuselage, held the legs in place and marked through the holes onto the tape. 5.5mm dia holes were drilled, the captive nuts glued into place in the ply u/c plate in the fuselage and the legs bolted into place - took all of 10mins!!
Next up I fitted the tailwheel. I have found a very nice unit from Graupner that is very good value (about £17) and suits this model very well. I cut a strip of 3mm ply approx 15mm x 70mm, marked the location for the captive nuts and fitted them. I then drilled two holes in the underside of the fuselage for the mounting bolts, glued the plate in place and tightened everything up. All done in 10mins again!!!
The spats, axles and wheels were next. Firstly I drilled 4mm holes in the u/c legs for the axles using the factory moulded indentations for position. Next I drilled a 4mm hole in both sides of both spats, once again using the indentations as guides. One hole on each spat was then enlarged using a dremel sanding cone to a diameter that allowed the axle bolt head to just slip through. A scrap piece of ply approx 20mm x 25mm was glued inside the spat. This is for the screw that sets the spat angle and secures it in place to screw into. NB Be sure to make a left and right spat!!!
I used some nice 3" Dubro Low bounce wheels that fit nicely and shouldn't flat spot when the model is left in the workshop!
To secure the spats in place, firstly ensure they are at the correct angle (make sure you have your tailwheel unit fitted or at least allow for it) then drill through the undercarriage leg and into the ply plate you secured inside the cowl. Simply screw into the ply plate and this will hold the spat securely in position.
First of all I slid the canopy latch into the plastic latch holder. This was a nice tight press fit and only needed a drop of CA to ensure it stayed in place for good. I then cut a slot for the latch pin in the top of the fuselage approximately 18mm long by about 3mm wide and made a hole in the fuselage canopy frame for the latch pin to protrude through. I tacked glued the latch in place, put plenty of red marker pen ink on the latch pin tip, placed the canopy in position and then let the latch spring onto the canopy. This gave me an accurate location of where to make the latch pin hole in the canopy.
Next up, I tack glued the ply plate in the fuselage, ensuring the slot was square and central. The phenolic hook was CA'd into the other ply plate. Next came the part that sounds tricky when you read the manual i.e. gluing the ply plate with phenolic hook into the canopy itself. This is very simple to do if you remember you can reach in through the front of the fuselage! I placed the canopy in place and taped it so it couldn't move, put a few drops of thick CA onto the ply plate and fitted it through the front fuselage opening. I let everything dry, removed the canopy and mixed up some 30min epoxy to secure everything in place I had tack glued.
The canopy seemed very secure so I decided not to opt for additional security the bolts but fitted a couple of plywood 'tongues' to stop any side movement that may occur in high alpha knife edge etc.
I have recently started to use the superb 'Double-loc' metal arms from SWB Manufacturing in the US. They are really high quality items that put my mind at ease having previously had an 8511 white servo disc fail on me. You can see the concept of the extra nut/bolt that holds the arm securely on the output shaft in the second photo.
The other thing to notice is that I am too lazy to put the stock servo braces together so I use JR servo side mounts. I bolt these to the servo bay cover using 3mm bolts and nyloc nuts. They allow for a really quick and easy build process. This entire aileron/horn servo setup took me less than 20mins to do!
The only 'effort' required using these mounts is to file away little of the servo bay surround nearest the aileron as it fouls the JR side mount slightly. Also, on the smaller models such as this Extra 2x2m you will sand to file a tiny bit off the side mount so as to achieve a taper to suit the thinning of the wing as it nears the aileron. You should be able to see what I mean in the top right hand corner picture.
Next up was the aileron horn. The slot was cleaned out slightly and the horn trial fitted. Next up I covered the area around the slot with masking tape and filled the slot with aeropoxy to ensure a VERY strong bond. The aileron pushrod was made up from the 3mm threaded rod, a 3mm ball link and 3mm clevis. DO NOT USE A BALL LINK ON THE AILERON CONTROL ARM as they can snap as the material is not able to withstand a twisting force that a ball link on one side of the arm would produce. The arm will never break if you use a clevis as shown in the picture.
Finally, the aileron servo lead was secured with a small clip to stop if flapping around inside the wing.