Friday, August 27, 2010

Hughes 500E Scale Fuselage and Trex 450 Sport


I just recently completed a scale project using Align's 500E fuselage and mechanics from the Trex 450 sport. Below, I've documented the build with video, pictures and notes in hopes of passing on some helpful building tips. I found the Align fuselage at Horizon Hobby and by using a 10% discount coupon they had sent me, I got a great deal. The build was a little more involved than I originally expected but quite fun. If you're thinking your going to just slide the Trex 450 Sport into this fuselage and fly, your going to be disappointed. Check out the video below for an overview of this project.





BUILD NOTES:

The first step was to attach the landing gear struts to the fuselage. I installed the skid pipes to the four struts, then slide the struts into the underside of the fuselage and into the slots in the fuselage's plywood floor. Once I had all the struts lined up I applied weight to the fuselage so that the struts were seated and the skid pipes sat flat on the ground. Then I applied 5 minute epoxy to the area where the struts meet the floor.



Once this had dried, I used painter's tape to mask off the bottom of the fuselage where the struts exit as seen in the next photo. Then I applied epoxy around the struts where they went through the bottom of the fuselage. By making sure the struts are firmly attached to the fuselage, you are reducing a possible cause of vibration.



Once all the epoxy joints have set, I sanded the top of the struts where the come up through the fuselage floor flush. This is where the riser blocks will set and you want full contact between the block and floor, again to reduce vibration.



Next I turned my attention to fitting the mechanics. I attached the supplied riser blocks to the bottom of the Trex Sport frame using the supplied four screws, which attach from the bottom of the blocks up into the frame.



The riser blocks are made up of several pieces of plywood that has been laminated. These have a reputation of separating. I chose to apply a coat of epoxy over the outside of these blocks to reinforce them. I also added a layer of dryer cloth (the sheet kind that you throw in with your clothes when they are drying to make them smell good) and epoxied over it as well.






The next step was to get the tail ready for installation into the fuselage. First I stripped off the two boom supports, tail push rod, push rod guides, horizontal fin and attachment block. These will not be used. Once this was done I set out to move the rudder servo so that it hung vertically below the boom. This required that I fabricate two angle brackets that attach to the existing brackets. I made these starting with a piece of 1-1/4" aluminum angle stock I found at the local hardware store. I cut 2 pieces about a 1/4" wide. I cut one side to fit the width of the servo and the other so as not to interfere with the existing top screw that holds the original bracket tight to the boom. I then had to mark and drill the holes for the servo as well as where the new bracket attaches to the old one. You will need (4) 2mmx5mm screws for attaching the brackets and (4) 2mmx12mm screws for attaching the servo.






I had to remove the entire tail block in order to install the boom into the fuselage. Putting a piece of tape over the end of the boom insured the belt didn't disappear into the boom.



It was also necessary to remove the two canopy mounting arms from the frame as they interfered with the fuselage. I replaced them with 2mmx5mm socket head screws.

In order to get the mechanics centered into the fuselage without the fuselage side hitting the elevator servo. I had to mount the elevator servo so that the rear flange of the servo was inside the frame with the rear mounting screw going in from the inside through the flange hole then into the servo nut. The front flange was mounted normally with the servo flange on the outside of the frame. This positioned the servo at an angle that allowed the fuselage to be installed with no interference.





With the elevator and rudder servos moved so as to fit in the fuselage, it was time to fashion the tail control rod. For this I used a Sullivan product called Gold-N-Rod No S580 that I found at my local hobby shop. It is a semi flexible carbon fiber rod that slides inside a nylon sleeve. I supported it in the middle to the boom by wrapping the sleeve with a 2" wide piece of aluminum tape. I used the aluminum tape as it won't stretch. The rod kit comes with two 2-56 threaded studs that will screw into the center of the carbon rod but in order for the other end to thread into the Trex ball link, I had to take the point of an xacto knife and bore out the link a little. Once I had both rod ends made up I cut the Gold-N-Rod to length leaving the carbon fiber rod about an inch longer that the outer sleeve. To find the center position of the pitch slider, I measured the distance from the inside of the slider to the tail block with the rudder to it's full right position. Then I calculated half that measurement, which would put the slider in the middle. This got me pretty close and I was able to set it exactly once I had it flying by putting the gyro in rate mode and making small adjustments until the tail would hold center.





Take note, when I relocated the rudder servo under the boom, it required that I flip the control horn to the opposite side which in turn required that I reverse my servo direction in the transmitter as well as setting reverse direction on the gyro.

Once I had everything set up and ready to go I attached the mechanics to the a set of gorilla gear by using tie wraps to secure the gear to the riser blocks. This was done so that I could test fly and adjust the new control rod and tail servo prior to installing the mechanics in the fuselage.



Installing the mechanics into the fuselage is a pretty straight forward process. With the tail components removed, I slide the boom down the center of the fuselage until the anti rotation bracket was up against the top of the fuselage as seen in the photo below. Then I took a 8" long tie wrap and placed around the frame and bottom of the fuselage floor. This held the frame in place while I centered it in the fuselage as well as being sure the boom was centered by installing the foam piece supplied with the kit. Once everything was where I wanted it, I installed the 4 screws that secure the riser blocks to the fuselage floor. I had to use a long bladed screw driver in order to reach the two rear screws. I left the tie wrap in place as an added safety precaution. One other thing I did was to install 6 extra 1/4" rare earth magnets on the flanges where the two fuselage half's join. This was suggested by other builders as some had problems with the front of the fuselage coming off in flight, not something I wanted to experience.







After the mechanics where installed, I fabricated a battery tray extension using a piece of 1/8"x1"x6" aluminum flat stock. I drilled holes and attached this to the existing tray using (4) 4-40 button head screws and nuts. I also used (1) 2mmx 12mm socket head screw with a small aluminum backing plate towards the opening of the frame to lock the plate down. The extended tray was added to provide a little weight to the nose as well as support for the battery as I wanted it located in the most forward position possible. With this set up and a Rhino 2250 30C battery, the heli balances at the center of gravity quite well.






The last step was for me to install the tail mechanics and the vertical and horizontal fins. I used epoxy glue for the fins. The fin pieces are covered with a vinyl type material and assemble with a mortise and tenon type joint. In order to get the best possible joint, I took a xacto knife and removed the vinyl from the tenons of the joint before gluing them. Be sure to keep the two fins 90 degrees to each other as the glue is drying.

Next was to re-install the tail block and attach the fins being sure I put blue locktite on all the screws as I installed them. I had to replace the two stock 2mmx18mm screws that hold the tail block onto the boom as they were to short. I had to purchase 2mmx 25mm screws which I found at RTL Fasteners. With the entire tail re-installed, I was ready to test fly this bird.



Only thing Left to do was to add some decals and a few foam strips around the skids to hold them in place and add more color for my tired eyes and this project is pretty much complete. I have chosen not to install the side window panels that come with the kit, as I'm afraid that the electronics might get to hot if the fuselage is all sealed up. I have seen other builder who installed black wire mesh screen for the windows so that the interior still sets airflow and in the future I might try this.



I've had a blast flying her and as I tweak my head speed, curves, expo and other settings, she keeps getting better and more fun to fly. I hope if you decide to take on a 500E build using your 450, that I have given you some insight into what you can expect and maybe made the process a little easier.

1 comment:

  1. Hello
    I liked your video too, is quite didactic and very helpful in assembling the kit.
    I have a big problem, I bought a kit and this missing piece of wood inside the cabin, or is missing the base where the heli gets stuck. I ask the friend if you have an impression of this part of the wood, so I could build one? Thank you very much for your help. Thank you.
    respectfully,

    ReplyDelete