BJ Craft Eternity
#27
Thread Starter
My Feedback: (5)
check the fuselage to make sure its level. I used the wing saddle and my eyeball for sanity check
install the stab tube and the FR4 washer
Check to see that it is level
CA glue in the tube socket
Before installing the flying stabs, I line the root with Felt.
Put one of the plywood disks on the tube to act as a spacer. This will help make sure you have not mounted the stab too close to the fuselage and have too much drag in movement. Obviously, you remove that spacer after you have finished the installation of the stab tubes.
If you look at the stab halves, you'll see the one with the hard point installed. Right side.
Drill the hole through the tube after you position the stab in its final location. The hardpoint is predrilled, the tube and socket are not.
Glue the stab tubes into the left side. Final fit looks good.
Last edited by shannah; 04-16-2018 at 03:58 PM.
#30
Thread Starter
My Feedback: (5)
Next I installed the elevator servo. I am using the Futaba S9170SV SBUS servo. B.J. recommends this servo for the elevator. It has great centering and holding capability which are important for the flying stab. It is also light which helps keep the weight down in the tail. I am using SBUS for all servos in the plane.
I installed the servo and made my own plywood mounting tabs. I went with a little thicker plywood and made sure the servo mounted in the same location relative to the Elevator control horn as I had on my previous BJ Craft G2 planes (Essence and Agenda). Everything lines up indentical on these planes so I was able to use the same elevator control pushrod that I had on the Agenda. This has my last set of MK ball bearing clevis' and I really wanted to use them on this plane. They are better than the HK versions. I don't like how easy it is to pop the bearing out of the HK bb clevis. Even though you mount it such that it won't pop off, it can still allow the clevis to slide down. I put the HK clevis version in my Agenda and moved the trusty MK unit over to the Eternity. I don't know how many flights these clevis' have, but its a ton. They are still great.
I installed the servo and made my own plywood mounting tabs. I went with a little thicker plywood and made sure the servo mounted in the same location relative to the Elevator control horn as I had on my previous BJ Craft G2 planes (Essence and Agenda). Everything lines up indentical on these planes so I was able to use the same elevator control pushrod that I had on the Agenda. This has my last set of MK ball bearing clevis' and I really wanted to use them on this plane. They are better than the HK versions. I don't like how easy it is to pop the bearing out of the HK bb clevis. Even though you mount it such that it won't pop off, it can still allow the clevis to slide down. I put the HK clevis version in my Agenda and moved the trusty MK unit over to the Eternity. I don't know how many flights these clevis' have, but its a ton. They are still great.
#32
Thread Starter
My Feedback: (5)
Now comes the part I haven't done in a long time and am kind of dreading. Installation of the rudder horns and pull pull system. I haven't done a pull pull cable installation in a pattern plane in over 10 years. Everything I have flown since the time I re-entered pattern flying has been a direct pushrod connection to the rudder with a servo in the tail. The last pull pull I installed was on my 40% Dalton 260 in about 2005 or so..... Anyway, things haven't changed and its all about alignment.
B.J. sent me a pic showing his rudder horn placement and the exit location for the pull pull cable. I pulled dimensions off this picture and carefully measured mine.
The exit hole is 10mm behind the aft end of the elevator servo well. It is 30mm below the bottom of the elevator servo well. I carefully measured this location and marked a line for reference. I put the fuselage at 0 degrees (using the left hatch base as the zero line) and double checked that this line was indeed projecting at zero.
I then projected the laser across the fuselage and was hoping to see it shine through the fuselage wall so I could mark the inside for the servo location. Unfortunately, the blue paint on the side is very opaque and the laser doesn't shine through it. It goes through the white very well however. So I just resorted to old school straight edge alignment. I also used a long CF shaft for double checking things.
I then measure from that projected line to the rudder and located the horn. I lowered the location of the horn to account for the height of the clevis that B.J. supplied for the pull pull system. He provides everything needed and it all looks good. I think I may go with C/L wire (as noted in another thread on RCU) because it won't stretch.
I cut the slots for the Rudder horns using his hinge slotting jig. I outlined the cut with an xacto first then used a 2mm drill to deepen it.
Next up will be locating the servo tray and cutting the exit hole (yikes) and final install.
B.J. sent me a pic showing his rudder horn placement and the exit location for the pull pull cable. I pulled dimensions off this picture and carefully measured mine.
The exit hole is 10mm behind the aft end of the elevator servo well. It is 30mm below the bottom of the elevator servo well. I carefully measured this location and marked a line for reference. I put the fuselage at 0 degrees (using the left hatch base as the zero line) and double checked that this line was indeed projecting at zero.
I then projected the laser across the fuselage and was hoping to see it shine through the fuselage wall so I could mark the inside for the servo location. Unfortunately, the blue paint on the side is very opaque and the laser doesn't shine through it. It goes through the white very well however. So I just resorted to old school straight edge alignment. I also used a long CF shaft for double checking things.
I then measure from that projected line to the rudder and located the horn. I lowered the location of the horn to account for the height of the clevis that B.J. supplied for the pull pull system. He provides everything needed and it all looks good. I think I may go with C/L wire (as noted in another thread on RCU) because it won't stretch.
I cut the slots for the Rudder horns using his hinge slotting jig. I outlined the cut with an xacto first then used a 2mm drill to deepen it.
Next up will be locating the servo tray and cutting the exit hole (yikes) and final install.
#36
Thread Starter
My Feedback: (5)
I will install the tray next. I am going to laminate it before installation, I always like to strengthen things a bit. I thought about using a glass/nomex panel for the rudder tray but I think laminating the supplied tray will be just as light and strong given it has supports.
#38
I had the same concerns then I noticed that the bearing was not fully pressed into the plastic.
I used a right sized dowel to press the bearing in the rest of the way.
As you said....if the clevis is mounted correctly....there is no way it can come off but I thought the bearing should be fully installed.
Best
Dave
#41
Thread Starter
My Feedback: (5)
Sorry for the long delay since my last post. I have been pretty busy, but this weekend I was able to get back to it. I finished up the rudder installation and have the tail section completed. Rigging up the pull pull cables reminded me how much I dislike that task. I really prefer the direct coupled rudder with the servo in the tail, but managing CG takes precedence so I had to re-familiarize myself with that task of stringing the cables. It came out fine.
#43
Thread Starter
My Feedback: (5)
I had to refresh my knowledge of good cables and methods for the pull pull setup. I went with some Brodak control line cable. Earlier posts on RCU indicate that this stuff doesn't stretch. So, I thought I would try it out. My previous experience with pull pull setups are that they need attention now and then. Hopefully this will hold up well and not develop slack.
#44
Thread Starter
My Feedback: (5)
I am installing the new BJ Craft X-Drive in the Eternity. I started a separate thread about the drive. I'll post some pics of the installation of the drive into the Eternity on this build thread. B.J. sent the motor with a firewall mount that fits the Eternity and also the rear support mount. I decided to make a firewall out of stronger plywood, but of the same thickness as his. There was only some minor fine tuning required.
He supplied the alignment disks to be used to center drive in the nose ring and also to provide proper spacing from the nose ring to the spinner backplate. This worked out to a 1.5mm gap. Everything lined up pretty easily.
The wires on the BJ Force motor exit on the side so I will probably mount my ESC on the side of the fuse rather than the bottom where I normally install the ESC's. B.J. said that the motor can peak at 120A so adequate cooling is required. I will also use a higher rated ESC so I am going with the Mezon Lite 130A.
I'll have more info to follow as I complete the build of the plane. Updates should be coming more frequently now that I have the drive unit.
He supplied the alignment disks to be used to center drive in the nose ring and also to provide proper spacing from the nose ring to the spinner backplate. This worked out to a 1.5mm gap. Everything lined up pretty easily.
The wires on the BJ Force motor exit on the side so I will probably mount my ESC on the side of the fuse rather than the bottom where I normally install the ESC's. B.J. said that the motor can peak at 120A so adequate cooling is required. I will also use a higher rated ESC so I am going with the Mezon Lite 130A.
I'll have more info to follow as I complete the build of the plane. Updates should be coming more frequently now that I have the drive unit.
#47
Thread Starter
My Feedback: (5)
I’m nearly done. I just have to install the battery tray and that’s it! I checked CG and know where to put the tray. I’ll put up some pics as I finish it up. I cut the air vent holes in the chin and belly. I didn’t cut the extra vent holes on the side of the fuse. I’ll wait and see if they are really necessary. I doubt they will make much difference.
I am using the Super lightweight tailwheel from F3AUnlimited. It looks similar to those really cool setups you get from RS or Japan but a lot cheaper. F3AUnlimited Super Lightweight Tail Wheel Assembly (F3ATWALW)
looks like my weight with Roaringtop 5800mah batts will be 4940. These batts weigh 1285g, so smaller packs will really bring the weight down
I am using the Super lightweight tailwheel from F3AUnlimited. It looks similar to those really cool setups you get from RS or Japan but a lot cheaper. F3AUnlimited Super Lightweight Tail Wheel Assembly (F3ATWALW)
looks like my weight with Roaringtop 5800mah batts will be 4940. These batts weigh 1285g, so smaller packs will really bring the weight down
#50
Excellent job. Where is everyone getting those blue foam plane stands? The couple times I've run across them they are always sold out. One thing to consider doing to help the gear box survive, as told to me by AJ based on his experience with the uber stiff BJ gear, is to run a piece of G10 or 2mm carbon plate that spans across the two landing gear to tie them together across the top on the inside so the twisting force can be transferred/shared between the two sides. It's been a source of irritation for me since I rarely get to fly off of paved runways. My last go around, I hysoled some hardwood block to tie the gear structure together better and then drilled holes between BJ's lite ply and the hardwood then inserted a lot of tiny cut off hardwood dowels between everything to pin them together and have never had an issue since, knock on wood. The weight was negligible.