BH YAK55M Assembly.
The assembly of a plane this size is very simple with lots of room to get your hands in and out of most places that would seem impossible with smaller planes. This is my 2nd BH airplane and the assembly is perty straight forward. I chose to start on the fuselage first. Most like to do the wings first but then once those are rigged up they normally get set aside until the fuselage is done for the final adjustments. I like and prefer to concentrate on the area at hand till its complete and move onto the next.
Motor Box. Its pre-drilled and just needs a slight reaming for some 3/8 bolts. However since this 3W275 is a rear carb engine the opening for the carb only needed a slight sand job to open it up for a little more ease of installing and removing the engine. The bottom of the motor box will need to be opened up somewhat for the air filter for clearance. I balsa tri-stocked the corners and glassed the whole inside of the box. I also closed off the box with a piece of 1/8 lite ply and glassed that in as well. On the other side of this newly fabbed bulkhead are the choke and throttle servos, both are SAVOX HV1267’s.
Fuel Tank. I made my own using an ARROWHEAD 100 oz water bottle. The 1/4in. feed nipple is from McMasters and the other 2 are from PSPMFG.com. From there I fabricated a saddle to hold this big bottle out of some EP foam and balsa sheeting and then glassed around that. I prefer the outside fuel filter that I found at my local auto parts store and made a little saddle for that as well. With this size of a tank I can easily run thru 2 Intermediate sequences with plenty to spare.
Wings and Tail Feathers. They are your everyday basic setup as you would find on most of today’s arf’s. I only needed to enlarge each hole a wee bit for the JRHV8911 servos to fit. Then followed up with a small pre-drill hole for the mount screws. All servo arms are SWB. Links are Hangar9 and Dubro ball ends. The main wing tube was a perfect snug fitting tube but the elevator tube needed some work as it was a sloppy fit. So out came the spray can of primer. I used almost the full can of primer to get it close then followed that up with several more coats of yellow Krylon. I waited a whole day for that to set up and then slightly sanded for a tight fit in the elevators. I also had to follow up again with some clear packing tape in the center of the tube, where it passes thru the fuselage, for that tight fit.
On the rudder I stripped off the original covering in favor of laying down an all white base with some red checks provided to me by Callie Graphics,,, she’s just an AWSOME Lady! For the tail wheel steering I opted to install a couple of 3/8in. dowels with 4-40 rods and Dubro ball ends for the steering instead of the traditional steering arm. Also on the 4mm C/F hinge rod I cut out a small square of some G-10 material, drilled a couple holes, epoxied the end of the C/F to that and screwed it down to keep the C/F rod from walking out. All C/F Hinge rods got this treatment.
Landing Gear and wheels. Only the best here,,, Whiterose 5 ½ mains with Whiterose titanium axels. The tail wheel assembly is also Whiterose with Vern’s new 50% Carbon Fiber spring. Straight forward install, drill some holes in the spring and screw onto the bottom of the fuselage. Here I prefer to use 1/4in. blue fuel tubing with zip-ties for the tail wheel steering via some Dubro ball ends to decrease the angle from the rudder to the tail wheel steering arm. When using the Whiterose axels you will need a custom spacer to slip over the axel because it’s a 1/4in axel and the hole in the landing gear is bigger. Vern fixed me up and I was good to go,,, Thanks Vern!
Fuselage. Not a whole lot of work needed here but I closed off all those slots with some lite cloth and epoxy. The main electronic compartment floor got some lite ply installed to make my electronic install/layout as seen in the pics. There are 4 servo holes for the rudder servos and again I opted for a 3 servo SWB tray. After I laid in the 1/8 lite ply floor I used the 4 servo holes as a guide and cut the slot for the servo tray. I did have to raise the tray up some to get the rudder cables to exit out the side of the fuselage properly,,, no big deal. The EQ10 has its own rubber foam mount and the RX also has its own mount as seen in the pics. Switches are the FROMECO Wolverine and Badger for the Smartfly Dual ignition setup. Batteries are the FROMECO 7800’s and a 5200 for the ignition. I made all my own 20 guage servo leads using the Deluxe Servo Lead wire kit from Hanson Hobbies and servo lead tube that I rolled up out of some brown wrapping paper. The snake skin wrapping for the rudder and elevator servos came from McMasters. On the bottom of the fuselage was an exit hole for the hot air. There I installed 4 sets of Louvers from Taildragger.The first 2 holes are the factory and I made another 2 in front of those.
Canopy. Don t know about you, but there about a million and one ways to install a canopy. The hardest part about installing a canopy,,, You have to walk away from it once its set in with epoxy. I did have to modify the canopy hatch a wee bit to get the needed clearance for the fuel tank. I don t remember what I used as a guide but it was perfect to make my modification and retain the structural integrity.
Maiden. My Starting CG was center of the wing tube. Weight is 65lbs dry. WX was sunny and temps in the 70’s here in the High Desert of SOCAL at a place called Rabbit Dry Lake. Fueled up, a quick step off of about 40 steps for a quick range check, fired up and another quick range check and she’s off-fly be free!
I only need a couple of clicks of aileron and it was on. Smooth roll out to climb and after another trim pass I put her thru some intermediate IMAC thingees. Its here where I noticed I was still nose heavy but very doable all on the first few minutes of flight,,, just an incredible feeling and a wonderful joy to fly.
Landing. It lands like big’ol cotton balled trainer with absolutely no bad tendencies.
If you have questions or want to see other pics or need a pic, I will be more than happy to help a brother out.
BH, as I said to you in a previous email, thanks for your time with answers to my questions and the builders that are building your planes,,, My plane was admired by all there at Rabbit Dry Lake today!
BV
