Monday, November 14, 2016

EMG-6 "Shop Notes" November 2016

"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.

November 12, 2016 

We have just finished up a marathon of 120 hr. Light Sport Repairman maintenance classes. October and November have been totally consumed by teaching. This class was the second half of a split class that that started three months ago and returned in late October to finish up the second half. The split class is normally smaller than the full class. This is held normally once a year to accommodate students that can't take 3 weeks off at a time.

Tuesday, November 1, 2016

Oleo Strut Sport Aviation / Experimenter "Technically Speaking" Article October 2016

Figure 1

Oleo Strut Basics

An oleo strut is a pneumatic air–oil hydraulic shock absorber. The primary purpose of the oleo strut, as you are probably already aware, is to absorb the landing loads on an aircraft. The force, which the aircraft structure is subject to, can be expressed in Newton’s 2nd law of physics F = M A or Force = Mass X Acceleration.  Acceleration is simply the change in velocity over time. If we can double the time interval for deceleration of the aircraft through the landing gear by lengthening the shock strut, you can see that we can reduce the total force exerted on the structure by half. This is the basis for incorporating the long struts on STOL (Short Takeoff and Landing) aircraft like the Just Aircraft SuperSTOL and the Fieseler Storch. Watching these aircraft performing short field operations, you can see what appears to be near vertical approaches, culminating in a very impressive squat of the aircraft as the long stroke landing gear struts absorb the landing loads.

Although there’s been many variations upon the oleo strut, there is some particular genius in its design. The basic physics incorporated in the operation of the oleo strut is what has made it so popular in so many different designs from the smallest aircraft to the largest. This basic design concept (Figure: 1) is so efficient that even the most modern of aircraft use the same basic principles that adorned aircraft landing gear designed and built as far back as the 1930s.

Figure 2

Let’s look at the basic operation of the oleo strut. (Figure: 2) Inside the strut we likely have a combination of Mill-H-5606 hydraulic fluid and dry air or nitrogen. The primary job of the air located in the upper chamber of the strut is to act as a spring. And the primary job of the hydraulic fluid, which is located in the lower chamber of the strut, is to regulate and transfer the loads from the lower half to the upper half of the strut and subsequently into the airframe. Located in between the upper and lower sections, but attached to the upper portion of the strut, is an orifice (Shown in Green). This orifice restricts the flow of hydraulic fluid from the lower half to the upper half of the strut. This basically lengthens the time interval during the compression stroke created by the landing gears impact with the ground. Many early strut designs simply stopped at this point using a fixed orifice to control the fluid transfer from the lower to the upper half of the strut. Later designs improved upon this concept by incorporating one more component called the metering pin (Shown in Pink) which takes the design to an entirely new level.  This metering pin is attached to the lower portion of the strut and is tapered starting at the top getting wider as it approaches the bottom section of the strut. This metering pin is co-located within the center of the orifice essentially creating a variable sized orifice. When the strut is fully extended, the gap between the orifice and the metering pin is relatively large allowing fluid to flow rapidly. According to Newton’s 2nd law the greatest amount of force imposed onto the landing gear structure will be at the point where we have the highest amount of deceleration (initial impact). As the rate of strut compression decreases, so does the force. This design allows the restriction between the orifice and metering pin to progressively get smaller and smaller essentially maintaining a constant force onto the structure while exponentially decreasing the rate of strut collapse. (Figure: 3) This allows the entire length of the lower section of strut to progressively collapse absorbing the landing loads over the longest time interval possible. It’s really quite a brilliant concept. A properly serviced strut is virtually impossible to bottom out because of this increasing restriction.  Landing forces that could cause the strut to bottom out would likely result in ripping the strut from the aircraft structure. Recognize that it is the fluid and only the fluid that is responsible for the struts’ amazing ability to absorb these landing loads. A strut that has lost its fluid is virtually useless. A strut without fluid is the equivalent of welding the bottom half of the strut to the upper portion strut in the collapsed position. The time interval for deceleration, in this case, drop off dramatically. This, in turn, increases the loads imposed into the structure to also increase proportionally. We often wonder how many of the accidents, where we see a collapsed nose strut, are a direct result of improper servicing or simply loss of fluid.

Monday, October 24, 2016

EMG-6 Webinar Hosted By EAA (Video)

EAA Hosted Webinar: EMG-6 Update October 2016

This is upgraded video of the EMG-6 webinar hosted by EAA. We have edited out some of the trivia and the questions at the end and added a significant amount of video to enhance the webinar.

Wednesday, October 19, 2016

EMG-6 "Shop Notes" October 2016

"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.

October 21, 2016 AOPA Electric Article

October 20, 2016

Tim sent the Webinar report from yesterday. We want to thank everyone for giving us such a high rating. And even though we only had 173 attendees we feel pretty good about the total attendance. Especially considering we were up against the 3rd presidential debate. Maybe that's why we did have such good attendance. Everyone looking for an escape. We will post the link to the webinar When it becomes available. 

We are getting ready for doing our new VLOG (Video blog). It will be called the  "Hangar 7 Video blog" We will be doing a weekly Video update with everything that is happening not only on the EMG-6 but with the going's on at Rainbow Aviation as well.

Tuesday, October 11, 2016

EMG-6 Electric Motor Glider Webinar Hosted by EAA

Register now and block your calendar to be able to attend the EMG-6 Electric Motor Glider webinar hosted by EAA. The webinar will be on Wednesday, October 19, 2016 at 7 PM to 8:30 PM central daylight time.

Our moderator for the webinar will be Tim Bogenhagen from EAA.

Click Here to Go to the Registration Page
EAA Registration

Saturday, October 1, 2016

Stronger 3-D Printed Parts (Part2) Sport Aviation / Experimenter "Technically Speaking" Article September 2016

3-D Printed Parts (Part 2)


3-D printing with ABS plastic provides tremendous versatility when it comes to post-processing of your part. When we refer to post-processing, we are simply talking about any process that modifies the original part after it comes out of the 3-D printer. Although there are many applications that do not require any post-processing, it is generally the post-processing that converts the part from a simple 3-D printed part into a usable part on your aircraft.

Figure 1:  Close up of Roughness in a 3D Printed Part


Tuesday, September 20, 2016

Solidworks 3D Modeling (Bing Carburetor) Step by Step (Videos)

 Bing Carburetor 3D Modeled In SolidWorks

These videos are a pre-release that are part of a larger series of videos compiling the step-by-step process of modeling all of the components on a Bing carburetor. The introductory video will not be completed until after all of the individual components have been modeled and we can provide a table of contents and a larger explanation along with links to each of of the individual videos.

If you are new to the SOLIDWORKS environment just watching the step-by-step process along with the trials and tribulations associated with trying to reverse engineer each 1 of these components can be helpful.

Each 1 of these videos are basically raw unedited video segments. As such there are a multitude of better ways to attack an approach the modeling of each of the components in this larger assembly. The idea behind the videos is to basically show a newcomer the thought process involved in being able to create each one of these individual components to a fairly high degree of accuracy.

Friday, September 16, 2016

EMG-6 "Shop Notes" September 2016

"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.

September 16, 2016 Production of Kits Continues

kit production continues. Jason has been putting together the subassembly kits and in this picture here he is assembling the components necessary for the horizontal stabilizer subassembly.

Monday, September 12, 2016

Builder Charlie Becker S/N 15-024 Oshkosh Wisconsin

Builder Charlie Becker S/N 15-024 Oshkosh Wisconsin

September 12, 2016

Charlie gets his landing gear mounted to the fuselage 4130 chromoly steel frame. Charlie is still currently in the lead for the 1st customer built EMG-6. 

This picture is indicative of Charlie's enthusiasm for aviation in general. He has several projects that these currently working on you can see the super cub in the background. Charlie is director of communities for EAA in Oshkosh. And his enthusiasm and love of the sport is very encouraging.

Although we made this page to highlight the most recent progress on Charlie's aircraft and we will continue to update this page as he sends us new photos. You may want to check out Charlie's Facebook page which is a great deal of more information about the EMG-6 project that he's working on.

Friday, September 9, 2016

3D Printed Vortex Generators Part 4 (Video)

In part 4 of 3D printed vortex generators video,  we go through the complete process of designing a vortex generator in SOLIDWORKS, exporting an STL file to the Zortrax software, and then printing and extracting the 3D printed vortex generator.

Wednesday, September 7, 2016

3-D Modeling Software “Home Built meets High-Tech” Sport Aviation / Experimenter "Technically Speaking" Article August 2016

3-D Modeling Software “home built meets high-tech”

In last month’s article we talked about the wide variety of opportunities available with 3-D printing. In this article, we want to talk about the process of creating those 3-D models. Within, literally, years of the initial offering of personal computers that software engineers started creating software for generating mechanical engineering drawings. And just like the computer industry itself, the exponential growth of CAD (computer-aided drafting) programs has blossomed into some of the most amazing collection of capabilities which only years ago were relegated to organizations such as NASA and Boeing. These capabilities have now become available to the average experimental aircraft builder/designer. If your aspirations revolve around being a component or aircraft designer, it is imperative that you recognize and embrace these new CAD technologies. For those holdouts, who do not wish to undergo the difficulty of learning to use a CAD program but still wish to be an aircraft designer, the only advice that we can offer is to lock yourself in the closet until you change your mind. Of course, we jest, but the capabilities of solid modeling software put the designer at such an advantage that the difficulties associated with learning the software are far outweighed by the results and capabilities that can be achieved.

Figure 1:  3D Solid Modeling Software Learning Curve

Friday, September 2, 2016

3D Printed Vortex Generators Part 3 (Video)

3-D printed vortex generators part 3. In this video we step through the installation process and placement of vortex generator using a template and commercial grade double sticky tape.

Monday, August 22, 2016

3D Printed Vortex Generators Part 2 (Video)

3-D printed vortex generators part 2. In this video we step through the installation process and placement of vortex generator version 1-150. We do a comparative analysis from the baseline tests that we conducted in part 1, and provide some analysis of the process. We are using the Quicksilver GT-500 that is currently being used as the tow aircraft for the EMG-6 electric motor glider as the test bed for our 3-D printed vortex generators.

Friday, August 19, 2016

EMG-6 "Shop Notes" August 2016

"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.

August 29,2016

Jason hard at work making up sub assembly kits. In this picture here Jason has been boxing up elevator Kits.

Thursday, August 18, 2016

3D Printed Vortex Generators Part 1 (Video)

In this video we begin the baseline testing for the 3-D printed vortex generator article. The baseline test was to get a video of the tuft tested wing as a comparative analysis against the additional tests that will be conducted with different 3-D printed vortex generators.

Thursday, August 11, 2016

Icom IC-A6 / IC-A24A Radio Mount (3D Printed)

3-D Printed Handheld Radio Mount

Although originally designed for the a Piper J-3 Cub, hence the color.  This mount can be used on any aircraft including the EMG-6. The radio mount is designed with a split clamp system which allows the installation and positioning on to a 7/8" diameter tube. We can design other size clamps that are interchangeable with different sized tubing if anyone has a specific request. The mounting system requires (4) (3/16" Dia) Cap Head Screws. (4) (3/16") Washers under the head of the cap screw. additionally there is a hex cut out in the clamp that will automatically hold a 3/16" nylon nut. (4) required. Mount can be mounted either horizontal or vertical relationship to the tube.

You can download the STL files if you wish to print your own radio mount. the files are located under 02-90-10-10 ICOM Radio Mount in the builders database.

Link to 3-D printing  STL files.

Tuesday, August 9, 2016

"Stronger 3-D Printed Parts (Part 1)" Sport Aviation / Experimenter "Technically Speaking" Article July 2016

Stronger 3-D Printed Parts (Part 1)

With the extensive proliferation of LPD (Layered Plastic Deposition) 3-D printers, their use in experimental aircraft has begun to grow exponentially. One of the most commonly asked questions, is whether or not we can reliably produce structural components using a 3D printer. The answer is an emphatic yes. Just as with any other process or material, it has its limitations as well as its strengths. Learning to utilize the 3-D printer’s strengths and work within its limitations is the key to its successful utilization.

Because the LPD printers are laying down one layer of plastic at a time the resulting component has a “grain” to it.  And much like wood and other materials the direction of the grain can significantly change the structural characteristics. If you have ever tried to karate chop a board, you know the trick is to strike the board along or parallel with the grain. The amount of force required to break the board across the grain can be 10 times greater than breaking the board with the grain.

Tuesday, July 19, 2016

Sterna Propeller

3 Bladed Sterna Propeller

July 19, 2016   We Receive The 3 Bladed Sterna Propeller

We received one of the propellers that we will be testing on the R and D motor. We have had extensive consultation with Sterna propellers about the propeller that would work the best on the EMG-6 with the 20 hp electric motor. We have selected a propeller blade section that will optimize the performance at a very specific profile. Mainly the ability to operate in a cruise configuration at 45 mph.  We currently have 2 other propellers that are designed for the same motor that we will be testing as well. as we develop data once we begin the flight test program will use this page to accumulate information about this propeller. If the propeller works as expected we plan to offer this as one of the primary propellers for use on the EMG-6. We also plan to become an OEM dealer for the propeller and have them in stock or customers of the EMG-6. We are also working with Sterna for a propeller to be used on the Polini 250 motor as well.

I was first introduced to the Sterna propeller 2 years ago at Air Venture 2014. Sterna propellers are manufactured in China. Their footprint into the US is still somewhat small compared to other manufacturers but they are beginning to gain popularity. If you are at Air Venture, Sterna will have a booth set up and you can talk to them and see some of their other products in one of the big hangers.

EMG-6 "Shop Notes" July 2016

"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.

July 19, 2016 Display Boards

Before every show we have to work on the advertising, brochures, and display boards to demonstrate some of the different capabilities and construction methods that we use. This year we have added to the display boards a 3-D printed parts board that shows some of the different components that are used both to manufacture the EMG-6 as well as components that are used directly on the aircraft. In addition after the show is over we have to stay a few days extra and do the "Homebuilder Hints" videos for EAA. This year They have requested that we do some videos on both the 3-D printing process as well is the Solid Works software.

Friday, July 15, 2016

EMG-6 Prototype #2 Test Flights Day 2 (Video)

EMG-6 Prototype #2 finishes certification on Thursday, we conduct 12 test flights on Friday, and aircraft is being disassembled on Saturday for the trip to EAA Air Venture 2016 in Oshkosh Wisconsin. This video is a compilation of the flights that occurred on Friday July 15, 2016

Thursday, July 14, 2016

First Test Flight of EMG-6 (Prototype #2) Video

Raw video of the first test flight on Prototype #2.  About 650 foot altitude on the tow. Just at sunset no lift left at all.  Aircraft handled well. Very Smooth, Stable and controllable.