July 2019: Maximillian (Max) Burton our Club Treasurer, crashed his Hanger 9 Ultra Stick Wednesday, July 17th. As you can see not pretty. However; since I was flying at the field to maiden one of my rebuilt mash-ups and witnessed the ‘thump’, and looked at the remaining pieces, I offered to rebuild it for Max as a project and post the process and pictures to the website. Luckily for Max the OS .65 Engine was fine along with the servos. The receiver was toast, yet the satellite receiver was good. Wheel pants pretty wrecked as well as fuel tank. Horizon has replacement wheel pants but may try to repair since I’m trying to do with parts on hand.
I did suggest Max buy a new receiver from Bruce Carr (A&E RC Products) at the Warbird Event so have that now. So here we go. If you haven’t rebuilt a crashed bird I hope this helps if you want to try sometime since a lot of crashes are not automatically ‘Trash Can Candidates’. Luckily, the crash recovery crew that day picked up almost all the pieces.
1. The starting point is to assess the amount of damage and determine if it is salvageable. So several questions you need to ask at this point:
A. Is this something I want and can do…..time, desire, skills, etc.?
B. Is there enough parts still left undamaged to make it reasonable, cost & time effective?
C. Are there any plans, guides, resources, spare parts, etc., available to use as templates or replacements?
2. If so, take everything back to the shop; if not, strip out everything useful and keep. Generally, not advisable to keep any radio gear.
NOTE: THERE IS ALWAYS MORE DAMAGE HIDDEN BY COVERING THAT HAS TO BE FOUND AS I WILL SHOW YOU LATER.
Fun comment from guy on Balsa Model Aircraft Builders Association FB group in response to my post of this rebuild…..“Nothing you can’t rebuild with a bottle of $2 epoxy and popsicle sticks”!
PART I – ASSESSMENT & INITIAL FIXES
As you can see from the damage the plane impacted on the right side of the nose almost straight in. Fortunately, the left side was pretty much intact and provided a template for making a new right side for the fuselage. I elected to do the fuselage repair first and save the wing for later.
3. First steps were to strip away some covering and square up the balsa underside, and then re-glue the fuselage where it had separated. I already know there is some additional damage at the tail but will do front- end first.The left side of the fuse where the power/receiver switch was needed some repair, so I removed that and glued and sanded the fuse while waiting on glue to dry.
4. The left side of fuse had a little nose damage which I repaired before using it as the template for the right side replacement. Also, I straightened out the servo tray and re-glued it at that time. After tracing the template onto some file folder stock I cut it out to trace onto the 1/8″ balsa strip.
STAY TUNED FOR PART II.
PART II – LANDING GEAR & WING HOLD DOWN BLOCKS
OK, so back to the rebuild, posting work done up to 7/30/19. Had to take a break because of elbow problem.
I had left off with replacing the right side of the fuselage and making some other minor fixes. The crash, as could be expected, ripped the landing gear from the plane but left the landing gear block pretty much intact attached to the gear. I removed this and noticed that the block still had one interlocking tab left that fit the left side of the fuselage. This was really fortunate in that it placed the gear block in the right position and also showed me where to correctly fit the repaired wing hold-down former to the right place. So I epoxied the gear block into the fuselage first using the alignment tab using Loctite EA 9460 also known as 9460 HYSOL. This 2-part epoxy is extremely strong and used by some of the best scale builders where extra strength is needed. It sands easily and doesn’t sag if applied vertically. Once dry I epoxied in the wing hold down former and glued on the right-side balsa fuse replacement. Note: The underside balsa sheeting would butt up against the back and front of the gear block. See later notes in Part III.
Once the fuselage was ready I needed to check the fit and alignment of the wing to the hold-downs. The wing was broke in many more places than was seen at first since the covering hid alot of the damage as mentioned at the beginning of this rebuild. The wing-bolt hold downs had been torn completely out of the wing and had to be repaired and glued back into the wing. Also, the leading edge was damaged quite a bit and I made some minor fixes to strengthen prior to fitting wing to the plane.
I used wood glue on the nylon bolt hold down piece to allow it move around as I fit the wing and bolted it into position so it would dry with everything aligned. This plane has a nice feature with a thin aluminum plate that spreads the force of the bolts over the wing hold down.
You can clearly see in the above photo the amount of damage to the wing that cracked the sheeting and tore off the hold downs. There is more wing damage and that will be worked on after I finish the fuselage with the firewall and fuel tank compartment and replace the underneath sheeting.
PART III – FIRE WALL / FUSELAGE & EMPENNAGE
Posting work done up to 8/9/19. Project has moved along well. Fuse rebuilt and covered and working on wing and wheel pants. Waiting for fuel tank, battery, and spinner to arrive.
Initially I was going to cut a brand new firewall but after looking again it made sense to keep the existing one and fix the minor broken part. This ensured the size was correct and I didn’t have to replace the blind nuts. I used popsicle sticks which are lite ply in a lot of places to fill minor areas and as reinforcing material.
I epoxied the repaired firewall into the fuse and also secured with screws on both sides. There is a application mixing gun that comes with the Loctite that you want to be sure to use since it makes it so easy to push out in equal parts to mix.
Added bottom 3/8″ balsa sheeting and 1/64″ lite ply over existing landing gear block. Finished sanded and prepped to apply covering. Reinstalled battery/receiver/charging switch.
Once this was finished I started working on the tail group since I had noticed that the stabilizer was cracked on both sides and the tail wheel bracket had been bent and the hold down screws ripped loose. I cut open two small areas where the elevator leading edges were cracked and used thin CA to repair then cut two small patches of covering.
The crash had also bent the tail wheel and ripped loose the mounting bracket. I straighten out the tail wheel and used a old trick for holding screws by inserting & epoxying pieces of Nyrod into the holes for the screws to bite into. This is especially useful in balsa or where the holes have wallowed out. I had to drill out the Nyrod slightly so the cap screws fit better.
I worked on a few things at a time as epoxy was drying, etc. One of these were the wheel pants which had been wrecked in the crash. Horizon offers replacements for about $20 but they were on backorder; and the goal here was to do the rebuild with items on hand and repair skills. Removed the broken wheel pants from the landing gear and then cleaned up and washed the fiberglass pants.
Next I used CA to make some fast fixes and stabilize the broken areas and place the ply holding plates back into position. Then with 3M AC aluminum tape I backed the inside missing areas. This tape is great as it sticks well to almost anything, is easily malleable to go around compound curves and its lightweight. Next step was applying fiberglass cloth to the areas. I mixed 30 minute epoxy with some fiberglass filler then coated the tape, laid the cloth on and then wetted out the cloth. I applied a second layer about 2 hours later. It turned out very strong and the filler allows it to be sanded better than without, while at the same time making it stronger. These will have to completed as wing is worked on. Additional filling, sanding, prep and painting.
Continuing to work on wheel pants. Using Bondo Glazing & Spot Putty to fill minor holes, cracks, low spots, etc. Its easy to work with. Spreads easily, dries fast, and easy to sand. Primed and painted.
PART IV – THE WING
Work on the wing is finished (Aug 12, 2109). Took longer than expected, as does most rebuild work. The ARF wing on this bird is Ok but not the strongest in some places. After repairs and recovering I believe its stronger. Initial repairs to a lot of cracked and damaged areas as you can see earlier in the rebuild. Replaced sections that were too badly damaged.
Covered separate sections and worked towards the center on the bottom of the wing. Used a wire hook to pull servo wires through access holes when finished. Also, used a pointed end on solder iron to punch thru and seal round screw holes on the servo hatches. Very useful in a lot of areas. Re-attached ailerons and flaps and re-glued hinges.
Finished the top of the wing by slightly changing stock covering pattern after repairing center section (see earlier photos), and then test fit to fuselage before final finish. Looking almost brand new at this point.
PART V – FUEL TANK COVER
Redesigned the fuel tank cover slightly to be a simple one-piece cover. I used the existing blind nut hold down and added a plastic wall screw anchor as a hold down at the back that slides into a hole in the wing hold down former. Also added a Velcro hold down strap and foam rubber pad underneath the Sullivan 12 oz. slant replacement fuel tank. While doing that I also added a Velcro hold down strap for the battery in the servo compartment just behind the wing hold down former.
PART VI – PROJECT COMPLETE & DELIVERED August 25, 2019
Completed the rebuild project with final prop adapter added for 2-1/4″ Dave Brown aluminum and final painting/clear coat on wheel pants. Delivered on August 25th, 2019. Enjoy and keep her flying Max!