Goldberg Tiger 120
11-16-2006, 08:56 AM
#1
Goldberg Tiger 120
Recently, I got a pretty good deal on a new Goldberg Tiger 120. The LHS had one in stock and it sat there for quite a while with people looking but not buying. So, he offered it to me at his cost. So, I jumped on it.
Ok. I brought it home and took a look at it.
First of all, I have a Tiger 60 and love it. It was my second plane after the NexSTAR trainer. That was several years ago. The Tiger 60 took a lot of abuse from me as a newly solo'ed pilot but no matter, it kept going and going and going. I changed the engine, original was an OS 61 SF. The front bearings were on their way when I first installed it, but I flew it that way for about a year until I decided it was time to rebuild the engine. Meanwhile, I bought a Super Tigre 75 and put that on the Tiger 60. That was fine except the internal baffle of the muffler came apart. Super Tigre replaced the muffler, but a short time later.. same thing. So, I switched from the stock muffler to a tuned pipe. That was great. In fact, I still have that setup and fly it a couple times a year.
Enter the Tiger 120. Shortly after I bought the plane, I decided that I would power it with a new OS 1.20 AX so I bought that engine for the plane. Then I started the build.
So far, here is what I've done:
1. I spent some time with light resin epoxy and a brush hitting all points where monocoat meets the wooden surface. This was to seal all joints and junctions along the wing saddle, and in the engine compartment... and elsewhere that I thought it may be necessary. I also coated any surface that was bare wood that may be exposed to any sort of fuel/oil contamination. I noticed that on my Tiger 60, after flying it for a year or so, that there was some oil seepage behind the wing mount and the wood back there had soaked in a little oil (stains showed up anyway). So, I thought I would avoid this by coating these surfaces with the thin epoxy resin.
2. I built the wing halves. I installed the aileron servo's and the flap servo's and the associated control surfaces. I used the included 4-40 hardware.
3. I modified how the tail control surfaces were to be controlled. I opted for one elevator servo (Airtronics High Torque BB servo) and used Sullivan Composite 4-40 control rods. Since the model already had tubes for the steel rods, I saved those for the pull-pull rudder configuration. Meanwhile, I installed the Sullivan Rod Tubes, leaving about 8 inches exposed at the rear, and put in 1/8 ply at each former with holes drilled through to secure the Sullivan Rod Tubes. Next, (see picture) I took the actual composite rods and made a piece of 1/2 inch ply that was about 1 inch long, drilled out two holes about 1/2 inch apart from each other using a drill that would make the installation of the rods very tight. I applied some medium CA and forced the rods in each hole. In between the two holes, I then drilled one hole same as the one for the two and forced a 2 inch piece of carbon composite rod in facing the opposite direction of the control rods themselves. I then applied some medium CA on a length of 4-40 threaded rod and forced that into the single composite rod and let the CA set. This produced a very strong and very light control rod that went into the two rods. The two rods were then passed through the tubes to the rear of the plane. I then put a 4-40 clevis on the threaded rod and attached that to the heavy duty servo arm on the servo. I hooked up the RX and checked it for free movement and resistance. None was detected. So far so good.
4. I bought some of the kevlar cable that was coated with vinyl and used that for the pull-pull rudder control. I passed the cables through the existing rods that were originally for the elevator and attached them to their respective sides of the rudder servo, which, incidentally, is another high-torque bb servo.
5. I am using a standard servo for the throttle, which I installed along with the other two servos.
Next, which remains to be done, is to install the horizontal stab, then the vertical stab, then the elevator and rudder and make those connections to the cables and rods already installed. Then I will make up the tail-dragger configuration, install the fuel tank and then finally the radio system, although I already have the RX installed for testing servo operations.
I am using a Polk Seeker III and Tracker II radio system on this plane.
I opted for the switch from standard steel rods for the elevator because I just don't like all that steel running parallel with an antenna in the fuselage. And, I have experience with my Venus II with the control using the same setup as I describe above, right down to the pull-pull system. It works great on that pattern plane so it should work just fine on the slightly heavier Tiger 120.
Does anyone of you have any easy... shortcuts... more sensible.. methods of putting the horizontal stab on straight? The measuring method the manual suggests is basically the same that all other model manufacturers suggest, but it seems a tad cumbersome and it seems to be a bit prone to error. I just want a nice straight installation. The vert stab is easy enough once I get the horizontal stab installed nice and straight and square. Any suggestions would be greatly appreciated.
I intend to break in the engine with a 15-10 or so prop. The fuel tank in this thing is huge.. somethign like 21 ounces!! Jeech.. should fly forever!!
Comments? Additions?? Anything.. would be appreciated.
DS.
Ok. I brought it home and took a look at it.
First of all, I have a Tiger 60 and love it. It was my second plane after the NexSTAR trainer. That was several years ago. The Tiger 60 took a lot of abuse from me as a newly solo'ed pilot but no matter, it kept going and going and going. I changed the engine, original was an OS 61 SF. The front bearings were on their way when I first installed it, but I flew it that way for about a year until I decided it was time to rebuild the engine. Meanwhile, I bought a Super Tigre 75 and put that on the Tiger 60. That was fine except the internal baffle of the muffler came apart. Super Tigre replaced the muffler, but a short time later.. same thing. So, I switched from the stock muffler to a tuned pipe. That was great. In fact, I still have that setup and fly it a couple times a year.
Enter the Tiger 120. Shortly after I bought the plane, I decided that I would power it with a new OS 1.20 AX so I bought that engine for the plane. Then I started the build.
So far, here is what I've done:
1. I spent some time with light resin epoxy and a brush hitting all points where monocoat meets the wooden surface. This was to seal all joints and junctions along the wing saddle, and in the engine compartment... and elsewhere that I thought it may be necessary. I also coated any surface that was bare wood that may be exposed to any sort of fuel/oil contamination. I noticed that on my Tiger 60, after flying it for a year or so, that there was some oil seepage behind the wing mount and the wood back there had soaked in a little oil (stains showed up anyway). So, I thought I would avoid this by coating these surfaces with the thin epoxy resin.
2. I built the wing halves. I installed the aileron servo's and the flap servo's and the associated control surfaces. I used the included 4-40 hardware.
3. I modified how the tail control surfaces were to be controlled. I opted for one elevator servo (Airtronics High Torque BB servo) and used Sullivan Composite 4-40 control rods. Since the model already had tubes for the steel rods, I saved those for the pull-pull rudder configuration. Meanwhile, I installed the Sullivan Rod Tubes, leaving about 8 inches exposed at the rear, and put in 1/8 ply at each former with holes drilled through to secure the Sullivan Rod Tubes. Next, (see picture) I took the actual composite rods and made a piece of 1/2 inch ply that was about 1 inch long, drilled out two holes about 1/2 inch apart from each other using a drill that would make the installation of the rods very tight. I applied some medium CA and forced the rods in each hole. In between the two holes, I then drilled one hole same as the one for the two and forced a 2 inch piece of carbon composite rod in facing the opposite direction of the control rods themselves. I then applied some medium CA on a length of 4-40 threaded rod and forced that into the single composite rod and let the CA set. This produced a very strong and very light control rod that went into the two rods. The two rods were then passed through the tubes to the rear of the plane. I then put a 4-40 clevis on the threaded rod and attached that to the heavy duty servo arm on the servo. I hooked up the RX and checked it for free movement and resistance. None was detected. So far so good.
4. I bought some of the kevlar cable that was coated with vinyl and used that for the pull-pull rudder control. I passed the cables through the existing rods that were originally for the elevator and attached them to their respective sides of the rudder servo, which, incidentally, is another high-torque bb servo.
5. I am using a standard servo for the throttle, which I installed along with the other two servos.
Next, which remains to be done, is to install the horizontal stab, then the vertical stab, then the elevator and rudder and make those connections to the cables and rods already installed. Then I will make up the tail-dragger configuration, install the fuel tank and then finally the radio system, although I already have the RX installed for testing servo operations.
I am using a Polk Seeker III and Tracker II radio system on this plane.
I opted for the switch from standard steel rods for the elevator because I just don't like all that steel running parallel with an antenna in the fuselage. And, I have experience with my Venus II with the control using the same setup as I describe above, right down to the pull-pull system. It works great on that pattern plane so it should work just fine on the slightly heavier Tiger 120.
Does anyone of you have any easy... shortcuts... more sensible.. methods of putting the horizontal stab on straight? The measuring method the manual suggests is basically the same that all other model manufacturers suggest, but it seems a tad cumbersome and it seems to be a bit prone to error. I just want a nice straight installation. The vert stab is easy enough once I get the horizontal stab installed nice and straight and square. Any suggestions would be greatly appreciated.
I intend to break in the engine with a 15-10 or so prop. The fuel tank in this thing is huge.. somethign like 21 ounces!! Jeech.. should fly forever!!
Comments? Additions?? Anything.. would be appreciated.
DS.
