Redneckmech
BH Five Scratch Build
I have been gradually working on my Bearhawk 5 for about a year now and am indebted to the many contributors here and on Youtube. There have been many times where I referred to someone else's build log to find just the picture I needed to clear up a question on the plans or forms so I am going to try to start documenting here to hopefully be able to pay it forward.
My progress is not quite as fast as I would like but between family and work it has been challenging to put the necessary time into the Bearhawk.
To add to that, the O-320 in my Cherokee decided it was time to start making metal and I have had to pick up a second part time job to cover the cost of the overhaul. I guess I cannot really blame it since it was last overhauled 52 years ago but the timing could have been better. I found metal (magnetic) in the screen at the oil change just before my checkride, after discussing it with 3 A&Ps I am friends with we determined that I "should" pull a cylinder immediately but since I already had my checkride scheduled in a week I shouldn't do much more damage if I could keep the time under 10 hours and re-check the screen. I passed my checkride on July 24 and as I was filling out IACRA I realized that it was 2 years to the day from when I had started flight training. Total flight time including my checkride was 4.5hr and as anticipated the amount of metal hadn't changed, I pulled a cylinder and found the expected lifter spalling..
Even though it is taking longer than I would like, I am looking at the build as a journey rather than the end goal so I am just enjoying the opportunity to learn new skills and apply the ones I already have.
Everything in this first post is documented in my EAA build log, but I am going to give a very brief overview of where I am and how I got here.
After researching options, I chose to use the router method for cutting the wing ribs. For me, this was a learning opportunity since I am not a woodworker. I was previously a welder by trade so woodworking is a bit of a black magic to me. My wife (who is wonderfully supporting) even was skeptical since the last project I built out of wood was a shooting bench built out of scrap pallets and I used a chainsaw for all the cuts.
Since the router method actually requires a router, my first step was to get one.. I purchased one off of Craigslist and after fighting chatter issues with the router discovered that it had a bent shaft. I then purchased a Dewalt DW618 and mounted it to my welding table. This solved several problems, 1. It is not in the way, 2. Chatter is much reduced (my welding table is made out of 1/2" steel plate), 3. I have plenty of working area for routing the forms. A win all the way around!!
I took a tip from N3UW and bought a 1/2 flush trim bit in addition to the 1/4" up-cut bit, I then replaced the 1/2" bearing with a 3/8 bearing and used that for trimming my form blocks. I also found that the best way of making consistent holes was to cut 1/8" undersize with the fly cutter and then route the last 1/8" of hole diameter. The final step was to route a 45 chamfer am pressing my flanges.
I traced and rough cut all of the .025" ribs, I placed a flap or aileron blank in between each nose rib and center rib. Any strip of material 1" or wider is saved for making stiffeners. Rough cutting was achieved with snips,
I discovered that my snips were scratching the material so I ground and polished the bolts that hold them together. Thankfully I was able to offset the finish cut and miss the scratches that were already in the material. I am now more vigilant but recommend polishing any new tool prior to using it.
When drilling the nose ribs I had issues with holes wandering so I purchased drill bushings used by cabinet makers for making drill jigs, Using these in my master cutting jig I can much more accurately drill the holes. I also took some brass stock that I had and turned brass pins that were .001 less than the drill bushing. They are a tight fit but work wonderfully for accurately aligning and pressing flanges.
I had a rubber stall mat that was on my shop floor when I moved in so I cut it into 12" squares and figured that I would try to use it for forming the wing ribs. A good friend of mine has a very well equipped shop and has a hydraulic press that I can use, unfortunately the hydraulic ram began leaking part way through and I was only able to form half of the nose ribs.
I experimented a bit since I had six squares of mat, I found that using 2 squares (1.5") gave the best results, I was forming both holes in the nose rib at the same time. My eldest son was very helpful and ran the hydraulic press for all 15 that I did. The mat worked well and similar can be purchased at the local farm store for about $65 which is considerably less than the recommended polyurethane.
lubrication was provided by the leaking hydraulic ram and WD-40 applied to each of the rib blanks prior to forming.
I experimented by starting with a smaller flange but I was able to get a 3/8" flange by using a form block flange length of .525" as recommended by SpruceForest in his wonderfully detailed document.
That is current progress to date, it sure doesn't seem like much when I put it all down here but it is slowly adding up!
My progress is not quite as fast as I would like but between family and work it has been challenging to put the necessary time into the Bearhawk.
To add to that, the O-320 in my Cherokee decided it was time to start making metal and I have had to pick up a second part time job to cover the cost of the overhaul. I guess I cannot really blame it since it was last overhauled 52 years ago but the timing could have been better. I found metal (magnetic) in the screen at the oil change just before my checkride, after discussing it with 3 A&Ps I am friends with we determined that I "should" pull a cylinder immediately but since I already had my checkride scheduled in a week I shouldn't do much more damage if I could keep the time under 10 hours and re-check the screen. I passed my checkride on July 24 and as I was filling out IACRA I realized that it was 2 years to the day from when I had started flight training. Total flight time including my checkride was 4.5hr and as anticipated the amount of metal hadn't changed, I pulled a cylinder and found the expected lifter spalling..
Even though it is taking longer than I would like, I am looking at the build as a journey rather than the end goal so I am just enjoying the opportunity to learn new skills and apply the ones I already have.
Everything in this first post is documented in my EAA build log, but I am going to give a very brief overview of where I am and how I got here.
After researching options, I chose to use the router method for cutting the wing ribs. For me, this was a learning opportunity since I am not a woodworker. I was previously a welder by trade so woodworking is a bit of a black magic to me. My wife (who is wonderfully supporting) even was skeptical since the last project I built out of wood was a shooting bench built out of scrap pallets and I used a chainsaw for all the cuts.
Since the router method actually requires a router, my first step was to get one.. I purchased one off of Craigslist and after fighting chatter issues with the router discovered that it had a bent shaft. I then purchased a Dewalt DW618 and mounted it to my welding table. This solved several problems, 1. It is not in the way, 2. Chatter is much reduced (my welding table is made out of 1/2" steel plate), 3. I have plenty of working area for routing the forms. A win all the way around!!
I took a tip from N3UW and bought a 1/2 flush trim bit in addition to the 1/4" up-cut bit, I then replaced the 1/2" bearing with a 3/8 bearing and used that for trimming my form blocks. I also found that the best way of making consistent holes was to cut 1/8" undersize with the fly cutter and then route the last 1/8" of hole diameter. The final step was to route a 45 chamfer am pressing my flanges.
I traced and rough cut all of the .025" ribs, I placed a flap or aileron blank in between each nose rib and center rib. Any strip of material 1" or wider is saved for making stiffeners. Rough cutting was achieved with snips,
I discovered that my snips were scratching the material so I ground and polished the bolts that hold them together. Thankfully I was able to offset the finish cut and miss the scratches that were already in the material. I am now more vigilant but recommend polishing any new tool prior to using it.
When drilling the nose ribs I had issues with holes wandering so I purchased drill bushings used by cabinet makers for making drill jigs, Using these in my master cutting jig I can much more accurately drill the holes. I also took some brass stock that I had and turned brass pins that were .001 less than the drill bushing. They are a tight fit but work wonderfully for accurately aligning and pressing flanges.
I had a rubber stall mat that was on my shop floor when I moved in so I cut it into 12" squares and figured that I would try to use it for forming the wing ribs. A good friend of mine has a very well equipped shop and has a hydraulic press that I can use, unfortunately the hydraulic ram began leaking part way through and I was only able to form half of the nose ribs.
I experimented a bit since I had six squares of mat, I found that using 2 squares (1.5") gave the best results, I was forming both holes in the nose rib at the same time. My eldest son was very helpful and ran the hydraulic press for all 15 that I did. The mat worked well and similar can be purchased at the local farm store for about $65 which is considerably less than the recommended polyurethane.
lubrication was provided by the leaking hydraulic ram and WD-40 applied to each of the rib blanks prior to forming.
I experimented by starting with a smaller flange but I was able to get a 3/8" flange by using a form block flange length of .525" as recommended by SpruceForest in his wonderfully detailed document.
That is current progress to date, it sure doesn't seem like much when I put it all down here but it is slowly adding up!
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