S-21 OUTBOUND PROGRESS
calculate and submit
1-12-17 Outbound Progress Report
In keeping with the design intent to maximize on building ease, the horizontal stabilizer features identical spars front and aft. Made of three nesting channels, the spars come final hole sized, de-burred and ready to cleco assemble, then rivet. Our tooling worked out very exact for the nesting, which can sometimes be a challenge. Because of the three channels, three different rib lengths are required between the spars. Your parts label as well as a sequence of tooling holes denotes rib location. Of course with a .10” difference in rib lengths it will be obvious if you try to fit one in the wrong location.
The skin layout should have all holes located and in final hole size. Even the holes are already in the spar caps, meaning no transfer drilling from skin to spar. To assure no twist in the horizontal stabilizer we may need to provide end jigs made of MDF that key into the rib tooling holes. These would be mounted to your build table in exact alignment and fixture the surface during riveting.
Vertical Fin Spar, Rudder and Elevator
The vertical fin spar is constant width, and is the same depth as the horizontal stabilizer spars. This means elevator and rudder can share hinges and ribs. At the root of the vertical fin spar is three layers of attach tangs. These transfer the loads into the bulkhead. Bolts will retain the vertical fin for ease of removal.
Since the rudder construction is like the elevator, we may include a trim tab that could be ground adjusted or in flight.
We are getting a lot of inquiries into what engines will officially work on the S-21. The mount and cowling will fit the Titan 340, which has the dyna-focal type 1 mount. The Lycoming 233 and 320 will also fit the mount and cowl. Other options may include the Rotax 912ULS, 912iS, 914, and when ready, the 915. There may need to be airframe adjustments to actually use the Rotax line of engines, as they are significantly lighter.
The Continental 0-200 could be a viable option, we have had some interest, and if it grows the mount may be offered.
Aileron and Flap Assembly Test
The aileron and flaps are based around a tube spar. The spar will come with one set of holes to match the skins. Assembly starts with clecoing the skin to the tube spar and rolling it just slightly to form the curve. Ribs are clecoed to the skin, then the spar is slid into place and squared up in the holding fixture (provided); the second set of holes are then transfer drilled into the tube. You would clean up the chips, and burrs and rivet. Prior to all this assembly you will have attached the flap and aileron hinge plates to the assigned ribs. The whole process should be a few hours to build all fours surfaces. The ailerons feature a heavy wall tube to provide most of the counter balance required.
New Order Form
Take a look at the new order form. We have dropped the BAK idea, in favor of offering more kits. The total cost is the same, and it offers the option of ordering kits as you progress with the build or have the finances. Some items are yet to be determined and will be listed as they are decided on.
Outbound Building Classes
Look online for a schedule for Outbound Building Classes, which will be held at the RANS factory or other locations. Expect this later in the year. We may even demonstrate the ease of build on some components at major airshows. We remain dedicated to the goal of bringing you a great performing plane with building ease that makes it precise, fun, and timely.
We received our first mill run of the XL lift strut, to be used on the S-21. As per RANS tradition, these lift struts will arrive to the builder CNC machined, with all of the holes and end profiles complete.
Thanks for stopping by, stay tuned! RJS
First production run of D and Z spars Arrive
We are stocked up and ready to start processing spars for the Outbound wings. Production will begin once we have completed the final stages of static testing and initial flight test. The spars are exceptional quality, straight, and measured to spec. They will be a joy to CNC machine and assemble. The spars will come with all machining completed and ready for the builder to begin assembly.
Tail Cone Skins Fitted
The tail cone is composed of 7 skins, all machined to final shape and holes located in final hole size. The top skins will be provided pre-formed to eliminate any tricky forming. This does impact packaging to some point, but the advantage is more consistent assembly with much smoother appearance. The window cut out will also be standard on the skins just aft of station 3.
The main spar will come with the special shaped doubler already installed by the factory. This is pilot drilled and final drilled once fitted to the cockpit cage.
The final version of the Wing Truss has been fitted. Final static testing, in full load path simulation, showed the truss went well past the 14,800 pounds required to meet 9 G’s at 1800 lbs. The test was halted when the static test stand started to deflect. This occurred at 16,000 pounds.
Wing Truss, Lift strut and fitting undergo full on static testing.
Some are asking why 9 positive and 6 negative? It is not to promote the Outbound as an aerobatic plane, but one that you can safely push to higher gross weights. To be a great akro mount, you need optimization is areas that dull the main mission, which is a fast cruising STOL with lots of payload. The extra load margin will also allow us to possibly expand the design into a four place. The extra margin comes with a minimal weight and cost impact due to the dual spar wing.
Wing truss bolts into the wing at the exact strut load path angle.
Later in the year we hope to have ready the 45-gallon fuel system. Provisions are made to install the larger tanks post assembly. This will be a matter of removing the wings and drilling out rivets. Those who want to start with the 32 gallon system can finish, fly and up-grade later.
End root rib is design for easy removal for tank replacement.
The aileron pulley assembly features super simple install and rigging. There is a rigging pin to lock the system into neutral.
Bell crank for aileron features a rigging pin, and extra large bearings for long life and smooth light action.
The big slotted flaps use an extra strong Teleflex coupled to a bell crank. This keeps all the flight loads on the cable in tension. Both aileron and flap actuation is internal, only the very streamline hinges are in the breeze. This means there is no need for push pull tube exit fairings, that cause drag and require extra build time.
Flap bell crank features a heavy duty Teleflex cable and adjustable push pull tube.
Close up of rear spar attach and flap hinges.
That's it for now, thanks for tuning in....more to come, RJS
Taking Shape 3-29-17
The prototype is taking shape along with the Raven featuring the 180 HP Titan. The Raven will be the test bed for the wing and engine install as we complete the first Outbound. It will also prove the retro adaption of the metal wing to the Raven and possibly the Courier.
Test assembly of the final static wing specimen. This is to double check hole line-ups and exits.
Test fitting to the prototype fuselage. Looks very good!
Looking at the single strut from the pilot seat. This is going to be a very common sight in the near future.
The internal wing truss fits neatly up inside the wing, aligned with the load path of the lift strut.
Detail of the internal wing truss and strut connection, no official bolts were used in the test fitting.
Thanks for tuning in! More to follow....RJS
2-14-17 Outbound Progress Report
Fuel System Options
The prototype Outbound and the first production run will feature a 32 gallon fuel system. There has been concern that 32 gallons is not enough for a hungry engine, like the Titan 340. We do believe you can extend your range considerably running at 50% power, where you would see maybe as little as 5.5 GPH. Cruise speed should be between 120 and 130 MPH at that power setting. The net range at this fuel burn would be 664 miles, minus the half hour reserve. At 8 GPH and 155 MPH the range would be 542 miles, minus reserve. The space where the 13 gallon tank resides will allow a direct replacement with 20 gallon tanks. This will create up to 45 gallons total depending on header tank size. The 45 gallon system will bump those range numbers to 960 and 794 miles respectively. Time aloft at 8 GPH goes from 4 to 5.6 hours. Both numbers are typical of general aviation planes. The case of extended range beyond this is for deep back country work. No doubt, we are looking at an even greater capacity. One design study goes as much as 64 gallons, but requires significant differences in the wing structure, added cost, weight and time. 4 to 5.6 hours of flight time makes for a very serviceable plane, that will accommodate most buyers of the S-21 Outbound. The more experienced pilots who do a lot of cross country will seldom exceed a 4 hour flight, more like 3 to 3.5 hours average.
We plan to have the 20 gallon tank available later in the year. If you have pre-ordered an Outbound we will send information on cost and delivery impact about going to the larger fuel system. From our experience with up-grading tank size in other models, it is very likely removing the root rib will allow a tank change out.
3-D Printed Parts
3-D printing is maturing slowly. The size, speed, resolution and material selection are the limiting factors preventing a landslide adaptation in our industry. However, there are current printers that have just crept over the payback line. We are flight testing parts made on a 3-D printer. And as with any new technology we are fast learning dozens of other applications. You can expect some of the parts in your Outbound kit to be 3-D printed. As for a full fuselage or wing, that will be a bit later…
Beefy Strut Fittings
The higher gross weight and load limit margins designed into the Outbound has resulted is some nice looking up-scaled components. Here are the fittings that are used to attach the lift struts to the fuselage. We pull tested the whole circuit of fittings to limit and ultimate load, partly to double check our numbers, but also because it really reassures the test pilot.
Tailcone Turtle Deck Skins
Layout and fit-up of the tail cone skins is about complete. As we install these parts, the stoutness of the tail cone becomes more apparent. Many are still curious about how the tailcone and cage connect. On the back of the steel cage are over 30 tabs and flanges that receive the longerons and skins. The skins overlap and also tie into receiver strips that are attached to many smaller tabs welded to the fuselage. This network of attach points creates a very even and well distributed load transfer to the cage. The bottom line is, if you tear the tailcone off of an Outbound it was not a hard landing, it was an airframe totaling crash.
A lot of thought goes into aircraft design. And safety is something we like to design into a model. We are big believers is surrounding the pilot and passenger with a crashworthy structure. This can be achieved in many ways. In the S-19 there is a high number of channels, stringers, and varying skin thickness to affect a “crash tub” that will retain shape in the event of an uncontrolled adverse impact. In the humble little Coyote ultralight, there is a network of aluminum tubes that also retain cabin shape. In the Coyote II , Raven and Courier we use welded steel tubing cages that surround you with protection. This is a proven system that not only provides safety, but building ease. Going the extra mile to build in safety may not impress everyone, but in the end it does benefit all.
Heavy Duty Landing Gear
The landing gear on the Outbound appear to be the same as the Raven, but closer inspection will reveal a thickness difference. A boost in thickness from .875” to 1” increases the leg strength to handle the 1800lb gross.
Titan 340 Engine Install
We are building a Raven with the Titan 340 engine. This install directly transfers to the S-21 Outbound, part for part. We should have this plane flying before Sun And Fun, and if test time is flown off, it will be there.
Next Up Wing Assembly and Test Flight
We are completing the last bits of parts and tooling for the production wings. One set will be flight tested and another wing will be static load tested, to final check the system and know the extent of our structural margins. I look forward to reporting on the flying properties of the new wing. We plan on shipping wing kits as soon as flight tests are completed. The time frame for this is in March to April. Maybe we will fly a Raven with Outbound wings to Sun and Fun, but please do not hold us to that promise. Thanks for tuning in, until next time stay safe, have fun and enjoy the flight! More to follow RJS