“EMG-6 Shop Notes” is a day-to-day accounting of what’s going on in the shop with the EMG-6 Electric Motor Glider.
May 29, 2017
We have added another series of drawings to the builders database.
May 27, 2017
We have been making a considerable amount of progress on the finished details of the aircraft. Most of the work that’s ongoing now is in conjunction with making additional drawings that correspond to the components that we are fitting to the aircraft. There’s a big difference between building a prototype where anything goes and a production airplane where everything has to be perfect and documented.
In this picture here were placing the axle mounting tubes onto the landing gear. We utilize a tube that runs from one side of the aircraft to the other side to ensure that the axles and wheels remain parallel.
The way that we achieve the on the proper amount of camber on the landing gear axles is to weld them in place while they are in perfect alignment from one side to the other. This is done with the upper fork end screwed all the way in. Once the fork and has been screwed out to the proper dimension it will leave the proper amount of positive camber.
This picture shows the axle tube welded in place with the lower shock strut attached to the lower attach fitting.
We are in the process of rigging all of the flight controls. To aid in this process we printed up a 3D printed fixture that holds the control stick exactly in the neutral configuration for the rigging process.
You can see in this picture that the aileron U- joint is perfectly aligned when the stick is located in the centering jig.
The wing tip testing and drilling fixture has gotten a few coats of polyurethane clear to protect it from the elements. This fixture is used to verify that the wing tip is exactly the same from airplane the airplane when it comes off of the bending machine. Also the 8 holes located at each end are for marking the drilling attachment locations.
This is 1 of the old landing gear welding fixtures that we made quite some time ago. Still holding up good. Probably time to make a new one out of some high-quality plywood so that we can add some additional features like the clamp positioning holes.
All of the CNC machines have been remaining fairly busy making small components. In this picture here we are manufacturing 1 of the bushings that holds the aileron torque tube in position.
That same aileron torque tube bushing undergoing an additional drilling process.
The complete rudder control system is now installed and we are just finishing up on some of the documentation for that. We should have the rudder control system drawings up within the next couple of days on the builders database.
We made a change to the rudder control horn fitting that raises up the push pull tube another 1.5 inches. This will allow for more clearance across the elevator torque tube.
In this picture here we see the lower rudder pulley with the rudder control cable installed. The elevator lower bell crank installed. And the aileron torque tube support bushing installed. All of the control systems utilize this one shaft for all of the control systems.
May 23, 2017
We have been working diligently on the landing gear system. We are narrowing in on the finalization of most of the drawings. After finalizing the drawings each component has to be built to the specifications on the drawings, assembled, and then test fit on the aircraft. If there are any glitches in the system we go back and remake the drawings and start the process over again. The last couple of days we been working on the shock strut assembly.
The 3D model version of the landing gear using the Azusa lite wheels. On prototype #3 we will be installing the Hagar wheels adapted to our bicycle break installation that we have designed and manufacture.
In this picture here we are cutting out .125 4130 chromoly washers which are used as the bearing surface for the shock strut spring face.
Although there is a lot of waste when manufacturing using the milling machine to cut out the sheet-metal parts, currently it’s our best option.
The new design fork end assembly before installation into the upper strut arm.
The lower strut is being manufactured in this picture here. A slot has to be cut into the tube through both sides so that the carrier bolt can slide with the landing gear as the spring compresses and de-compresses.
A special manufacturing jig that holds the lower shock strut assembly for welding the washers in place.
In this picture it shows the washer welded in place.
Cutting out the upper shock strut attach fittings that will be welded to the fuselage frame. These are manufactured from .25 4130 steel.
The milling machine has to travel fairly slow in order to cut the .25 thick material all in one shot. So we program the machine to cut 4 pieces at a time.
Using the lathe to trim 3 inch diameter billet stock with a perfect face in order to Chuck the material into the milling machine vice.
After machining were left with a very smooth face which can be inserted into the milling machine vice. Only .25 inch of the part will be held in place on the vice while the milling takes place.
This block here will become the adapter which offsets the bicycle brake rotor from the inside of the hub on the Hagar wheel assemblies. In this picture here were using a .7 end mill to do most of the machining.
A before and after pictures showing the billet material and the semi finished final product in the foreground. Takes about 4 hours start to finish for the milling machine to crank out 1 of these parts.
Kind of an ingenious (if I do say so myself) system that we developed for holding the tooling during the machining process. These are 3D printed holders that slide into the slots on the milling bed and are numbered according to the tool number. This is 1 of the many ways that we can make it easy for a rookie to operate the machine.
One of the landing gear legs prepped and ready for the installation of the axle mounting tube.
Jason here is doing some fine-tuning to provide clearance for the carrier bolt to slide up and down on the lower shock assembly.
May 20, 2017
We have posted a new series of drawings on the landing gear shock strut assembly to the builders database.
May 19, 2017
We are continuing to make progress on the drawings for the conventional landing gear set up. We have a multitude of different landing gear configurations for the aircraft. You probably saw on the early videos flying the aircraft with a model wheel configuration and no steerable tail wheel (Still my favorite configuration to date). We also have a nose wheel configuration which we have not tested, and two or three ideas for using a simple centerline skid or two conventional configuration skids. However of all of the configurations the general consensus seems to be that everyone would like to have the conventional landing gear with a steerable tail wheel.
We been working on several modifications to the conventional landing gear system that will allow us to bring the cost of construction down. You may have seen on prototype number two where we used a compression strut with a hydraulic/air spring inside of the streamlined strut material. Although the drag reduction on that system was fairly substantial there were no weight benefits. On prototype number one we use some surplus fork ends on the top half of the shock strut. Turns out these are $80 apiece. “Well that’s not gonna work”. So we redesigned the upper end of the shock strut with a commercial grade fork end costing about $8 apiece. The fork and requires a little modification to provide clearance and we had to redesign the method by which we are going to manufacture and install the threaded insert that gets welded into the top of the shock strut.
In the pictures below we are modifying some of the original landing gear components to fit the new design. We went through several design modifications on prototype # 1 and the final result showed that this spring in the picture below was perfect. If you watch the video below at about frame 3:20 you can see the action of the landing gear spring when flying the aircraft with all the weight on just one wheel.
The blue Springs are the Springs off of prototype #1. You can see the ugly lower attach fitting that was originally used on #1. As a result we have upgraded that lower fitting to a CNC machined fitting manufactured from 7075 T6 aluminum.
The new style fitting that attaches the shock strut to the lower landing gear assembly. Much cleaner.
These are the new lower landing gear attach fittings after being processed with four different CNC machine operations.
First step in the process is to run the 1.25 inch billet stock through the CNC turret lathe. This cuts the basic profile.
After each component is finished the parts catcher flings the parts into the housing on the door of the machine.
The next step is to put the basic part into the Rotary Chuck on the CNC mill which undergoes three more operations in two different axis. Profiling and drilling the part to the final shape.
More of the control system parts after manufacturing and powder coating. This is the aileron control horn bearing support.
Each one of the parts has to be tested against the tube size to ensure that there is no conflict from the powder coating process. For parts that are permanently bolted to one of the pivot tubes the necessity for reaming is eliminated. All of the tubes that interface our .058 wall thickness which leaves about .007 clearance.
More aileron bell crank’s for the lower bell crank location.
Most all of the parts that undergo the welding and powder coating process that also incorporate a nylon bearing, require reaming. The nylon bearing needs to operate very smoothly in order to reduce friction within the control system. We have found that chucking the part in the lathe and running the reamer chucked into the drill head is the most reliable way to ensure a clean center bearing surface.
Austin is operating the CNC mill with Tap-Matic tapping head. The tapping process is all automated and simply requires removal and replacement of the parts from the milling vice.
We program the machine so that the tap goes over and dunks itself in tapping oil before moving over to the part to be tapped. This ensures that the lubrication process does not get forgotten. Many broken taps until we develop the system.
May 18, 2017
We been working very closely with Gary of ultralight sails of Canada to develop the wing sail templates. Gary is developing a digital template of each one of the sail envelopes. In order to create accurate templates we need to send drawing information on a regular basis. In the drawings below we see some of the dimensions for the arc lengths at each one of the ribs in the horizontal stabilizer. These dimensions can then be input into Gary’s software in order to generate a digital representation of the sailcloth envelope.
Many dimensioned drawings are also provided to be able to verify the digital template.
May 17, 2017
We put the wings back onto the aircraft we have put the wings back onto the aircraft so that we can continue working on the flight control subsystems.
I’ve been putting off a decision on which landing gear configurations go with on this particular aircraft. “Landing gear” such a waste. It’s just more weight and more drag. If it wasn’t for that takeoff and landing thing… Since were going to be flying the aircraft at the air show this year I guess I’m stuck with putting it back onto the conventional landing gear system. (Tail dragger)
Jason’s been doing a pretty clean installation of the wiring harness from the engine to the instrument panel.
A look at the backside of the instrument panel.
We’re able to get the electrical system for the starter functioning. Did a test run of the starter and re-lubricated the engine with some two-stroke fogging oil.
We still have a few standoffs to weld to the frame to make the wiring harness will cleaner.
A side view of the center instrument panel.
My birthday today. My mother-in-law, Barbara, brought by some brownies. Of course a large straight slot screwdriver is perfect for dishing up the brownies. This usually keeps others from wanting any.
Gary from ultralight sails of Canada has requested a mockup wing of the EMG-6. This will assist him in getting the fabric just right around these very complex curves at the tip.
We have a CNC cut wing tip testing guide to ensure that each wing tip is identical to the next one after coming out of the bending machine.
We continue to keep the deburring machine fairly active. We’ve got a whole series of control system components that have to undergo the deburring process.
May 16, 2017
New drawings added to the builders database for the flight control system.
May 15, 2017
We are starting to reassemble the aircraft. We’ve had the wings off for nearly 3 weeks now while the maintenance class was ongoing. We are now making a big push to get the airplane flight ready.
In this picture here Jason is changing out the rear wing spar attach fittings with the new lighter weight fittings that we have just finished manufacturing.
A close-up of the rear spar wing attach fitting being bolted in place.
Austin has been working in the machine shop cutting parts for the flight control systems.
Some of the tubing segments that make up part of the aileron control system
All of the CNC machines have been working pretty much full-time making parts over the last week or so. In this picture here were cutting out control system parts from 4130 chromoly steel.
After the parts come off of the milling machine they still have to be sanded and run through the deburring machine.
Some of the control system fittings ready for welding.
The lathe has been cranking out parts on a fairly steady basis. These are some of the rod and inserts for some of the smaller diameter pushrod tubes on both the elevator and aileron control system.
Jason continues to work on the wiring for the aircraft. In this picture here we see the interface block that was manufactured in order to install the fuse box assembly.
May 12, 2017
We are continuing to add more drawings to the builders database. This week we been working on the elevator control system.
The #3 push pull tube for the elevator control system is the very long push pull tube that transitions from the upper bell crank located inside of the fuselage boom assembly and transitions to the aft bell crank assembly that controls the elevators individually.
The elevator push pull tube is manufactured from .75×.035 6061 T6 aluminum. It is larger than the other push pull tubes because of its length.
Elevator push-pull Tube #1
May 11, 2017
With the fuse box mounted onto the adapter it will allow easy mounting to the backside of the ICOM radio mount on the instrument panel.
Machining the elevator control built crank.
The 4130 steel is pretty hard on the tooling. This is a job for a waterjet or a laser cutter. Wish we had either. We have outsourced this in the past but even purchasing lots of tooling seems to be much cheaper than having these parts laser cut for small quantities.
May 10, 2017
In this picture you can see the reason for the offset in the male die. The aileron control horn is a fairly deep you section with a significant taper towards the top.
It took us a multitude of different dies in order to be able to have the bends come out just right.
The 3D printer fixture has threaded holes for bolts to make micro adjustments on the setback during the bending process.
After the parts have been bent in the CNC press brake the ears require a small bend of about 4°.
This machinist vise works really well as allows the opposite ear to talk underneath the head of the vice during the bending process.
May 9, 2017
We have redesigned the elevator control system built crank so that the aft built crank and the upper built crank are identical parts allowing us to reduce the machining costs.
Most all of the control system drawings that are manufactured from 4130 steel have templates that allow the builder to manufacture their own parts using a drill press, bandsaw, bench grinder and some other hand tools. By printing the template at 100% scale you can use contact cement on the backside of the paper, then glue the template to a piece of sheet metal. We begin by center punching all of the reference holes then connecting the straight lines. This is one of the ways that we can reduce the costs to the builder.
In addition to providing the templates for manufacturing with hand tools. We also provide the DXF files that allow those with equipment to export to a waterjet, milling machine, laser.
May 8, 2017
For the last three weeks we been actively engaged in the LSRM maintenance class. This is the commercial break that happens 3 to 4 times a year that pays for the research and development of the EMG-6 project.
We now have a basically clear slate until the Oshkosh air venture 2017 airshow. We should now be able to blog on a daily basis about the progress that were making on the EMG-6. So if you are an avid follower of the progress that we do make the next three months should be quite exciting.
Latest machine that we purchased was a $1000 vibratory tumbling machine that deburs and finishes both aluminum and steel parts
We use ceramic cones of various shapes and sizes inside the tub. This machine really gets with the program and it will de-burr the typical batch of aluminum parts and about 35 minutes.
The rudder control horns freshly out of the deburring machine
We been waiting on the deburring machine for a lot of parts. This box contains the horizontal stabilizer folding bracket for the leading-edge.
This box contains the first run of horizontal stabilizer folding brackets. All of these had to be rejected because the first design ended up with the inboard rib of the horizontal stabilizer interfering with the fuselage by only .040″ . Even though it was close it would have caused the fabric to wear in the folded position and as a result we had to redesign all of the brackets for both the forward and main spar on the horizontal stabilizer.
One of the aileron control horns freshly out of the tumbling machine.
We have found a commercial blade style fused box that will run all of the systems on the EMG-6. It is lightweight and contains LED warning lights if a fuse has blown.
Inside the fuse box shows the blade holders. We are currently printing a 3D printed interface that will adapt the fuse holder to the aft section of the instrument panel.
We have been CNC machining the aileron control arms.
We had to make special bending dies to allow us to bend the control arms because of their Deep Throat and tight bend.
We have found that 3D printing jigs to hold the parts in place during the bending process is very accurate and easy to set up.
In this picture you can see the necessity for the offset in the bending male die. We actually ended up with having to make several different tooling dies until we came up with this one that work just perfectly.
The aileron control horns freshly out of the deburring machine.
The horizontal stabilizers in the folded configuration. If the horizontal stabilizer total height is a factor the leading-edge can be disengage from the bracket and the horizontal stabilizer and elevator folded forward in order to reduce the total height.
A view from the aft of the aircraft with the horizontal stabilizers folded up. You can just see the wing spar leading-edge fitting sticking out of the sides.
A view from the front of the aircraft with the tail folded. In this picture here you can see that we are beginning all of the wiring on the instrument panel.
This fixture is for testing and marking the wing tip bow after it is bent in the tube bending machine. This ensures that all of the tubes are bent to exactly the same dimensions and allows us to mark the indexing holes to ensure proper drilling for installation onto the wings.
May 7, 2017
Aircraft Sitting on the Belly
Wiring and instrument installation
Radiator, header tank, and fuel system installation coming along
The completed wing installation and tail assembly attached to the aircraft.
Control system fittings
Manufacturing of the wing main and trailing spars
Machining the lift struts
May 5, 2017
Our schedule has been so overwhelming for the last two months that we have, by necessity, had to take a break from blogging.