S-21 OUTBOUND PROGRESS
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The finish tip fits up nice and sleek
Wing Painting Jigs tie into the wing tip attach bolts. You will want to make a similar device. Being able to pivot the wing makes it easy to paint like a pro.
Installing the Wings on the Raven
It went fairly smooth. The skylight was able to conform to the slightly different airfoil of the metal wing. The wing cuffs were also recycled.
Aft wing spar fitting and special inner flap hinge. The hinge had to be shaped to allow the door to fully open. The fancy fitting has compliance fore and aft to allow for any slight variations in wing positions.
Shelly has skinny arms, so we volunteered her to fish out the pitot static lines. We “predicted” we could install after skinning.
Flight testing of Wings
Flight tests show the wing to perform as well as expected. The ailerons are nice and light, with a brisk roll rate. Roll coupling test show adverse yaw is less than a Raven with the stock wing. I expect it to be even less on the Outbound due to the longer tail moment.
Performance of the Outbound wing on the Raven is very respectable. A Rotax powered Outbound should be a very practical plane with good performance numbers. At 1340 gross on 100 plus degree days it still averages 800 FPM to 1000’ AGL. Further testing showed a service ceiling of 15,900 at a gross of 1400. A 100 HP Rotax powered Raven or Outbound should top out around 14,000 at 1500 gross.
Stalls are gentle, with a noticeable burble prior to the break, and a light release and no power gets the wing flying in an instant.
The flaps are easy to deploy, even above Vfe. Flaps reduce the stall speed a good 8 or more MPH.
Rolls are smooth, with a rate of 112 degrees per second. Loops are with plenty of airspeed over the top to keep wings level. Speed build out of the loop is higher than the stock Raven wing, as should be expected. ¼ and ½ turn spins show rotation halted at 30 degrees or less. More spin work will follow.
I flew the wing into the same places I have taken the standard Raven wing and it performs very similar in take off and landing distances, guessing about 25 to 50 more feet required. The wing flies close to the stock Raven wing, accurate comparisons can only happen when we have a chance to fly against a stock Raven. The intent is to validate the wing for use on the S-21, and from how well it flies with only 100 HP it should be a hoot with the Titan 340. Thanks, more to come! RJS
Outbound Progress Report
Flight Testing of the Wing
We now have over 60 hours of flight time on the 141 wing. This includes going to the Black Hills Fly-in, where you can really get an idea of how it stacks up against not only RANS planes but other brands. I must say I came away very impressed with the performance and handling at the higher elevation. Prior to departure I opted to pitch down the prop by 1 degree. This created a shorter take off, but no real increase in climb rate. The Vy is about 65 to 70 IAS, and Vx is 60 MPH. With only the 100 HP Rotax we saw respectable climb-outs from all the sites we landed at, even with full fuel and a 230 pound passenger. I really wished I had not down pitched the prop, because I lost about 12 MPH in cruise speed. Even with less pitch I was able to cruise at 103 MPH typically, turning 5500 RPM. One more degree was giving me a solid 115 MPH. With the 100 HP you simply have to let the plane build a little speed then it really takes off. This does mean with greater power you will see shorter take off runs and greatly improved climb rates. All in all, the wing is performing equal with the original wing when it comes to take off and landing distances, and rates of climb but, does have a higher cruise speed, even with the prop pitched down.
Wing tips have been giving us some production headaches. We are re-tooling them over to a better material. This will cause a week delay in shipments. If we still have issues we will delay shipping the wing tips with the wing kits and send them with the fuselage, or finishing kits.
Kits are Shipping!
We are packing kits daily. Production has been full speed ahead, but we are finding our speed is coming up a bit slower than we hoped. We are gaining daily, and hope you will be patient. We will not compromise quality for the sake of speed.
After the damage the mock up received heading to Oshkosh we decided to add a two bulkheads. They are placed between station 4 and 5. The main reason has nothing to with strength or the big dent the flying off the trailer induced. It is all about getting the skins to lay with no pillowing between the stations and still be able to use the light weight pre-drilled stringers.
Once the fuselage is back together we will do limit load testing and then complete assembly of this "rough " prototype for flight testing.
Thanks for stopping in, more to follow, RJS
Outbound Progress Report 14
Choosing an Engine:
A new design starts with an engine choice, and for the Outbound that was the Titan 340. No doubt this will prove a very viable and well fitted engine. However, there are several engine options that will compliment the S-21 airframe. Over 50% of the Outbound program is actually flying, since the Raven and Outbound share airframe components from Station 3 forward. Our demo Raven with the 141 wing has only the additional drag of the wire braced tail group. The flight performance of the 141 wing on the Raven with the 100 HP is very good and backs up our predictions of performance using the 180 HP Titian. The S-21 will be a very versatile airframe allowing a large spread of engine weights and horsepower. Here is the current list of engines that will be factory supported, either in full install kits or partial kits. More options may be added in the future.
Titan 340 (full install kit)
Many Lycoming 320's. Type 1dynafocal mounts and some variations of intake and accessory case. (partial install kit will include mount, cowling, air box, controls, oil cooler, and possibly baffle kits, and prop spacers if SAE 2)
Lycoming 0- 233 (full install kit)
Rotax 912ULS (full install kit)
Rotax 912iS (partial)
Rotax 914 (partial)
Rotax 915 (partial)
The outbound rudder system has the option for tail wheel steering. This requires a second set of cables and pulleys coming off the rudder horn. The challenge has been to keep this from becoming an award winning Rube Goldberg design. Our solution is to have the horn with cable attach locations for both the rudder and tail wheel steer cables. In the early design phase we debated about having a free steerable tail wheel, but that was bumped, because relying on brakes only for non-aerodynamic steerage can have an expensive failure mode. The system seems to function well, and with the large access hatch in the belly, switching from a tail wheel to a nose wheel should be fairly low in effort and contortions.
After Oshkosh I barreled into the repair of the fuselage and after a few hours it was ready to close up and was fully restored. However, we decided to take our time and do a full dress rehearsal of all systems aft of station -3. It has been slow but, things are working out as planned and we should see a completed tail group and fuselage enter limit load testing in the next report.
We cast the final tooling and are running wing tips! Wing tips will start showing up in the wing kits. Those shipped prior to the tooling being completed will receive wing tips in the finishing or fuselage kit.
Aileron and Flap Tweaks:
I like a really fun feel to the controls of a plane. The kind of feel that makes you want to crank and bank. The initial aileron feel of the 141 wing was great, but something kept bugging me and after several hours of flying, it was decided to increase the aileron span about 8" and reduce the flaps the same. We noted the flaps being very effective so, 8" lost in span would have little impact however, 8" more inches of aileron would be something we could feel and measure. Flight testing proved this to be right on. We increased the self centering pressure to overcome the auto pilot friction, and there it was, that sweet handling I was hoping for. Now with no AP the stick force in roll is only one pound and two pounds with AP attached. Two pounds is light and fun, yet still with enough feel and feedback not to be touchy. The bottom line is, the changes did not hurt the excellent flaps, it only increased roll rate, reduced roll stick pressure, and increased self centering.
Fast Building Flaps
At the 2017 RANS Fly-In we held a flap building seminar. About an hour later a pair of flaps were completed. We have been bragging about fast build times, and to the many gathered at the fly-in, it became real. The controls surfaces are just one area where we have approached the design process with a high priority on ease of build. It leaves us with an interesting question as what to build during our seminars. Obviously we need a bigger challenge than a set of flaps! Perhaps we can include some wing and fuselage construction? I would love your input on this topic, email us your thoughts.
We will be adding to the manual some plans for building fixtures for painting most of the components of the S-21. These pictures show how we fix the wings into a typical A frame pivot system.
Thanks for tuning in and more to come soon! RJS
Horizontal and Vertical Stabilizers
The horizontal stabilizer is one-piece, making assembly and install easy. Everything comes as pre-fabricated as possible and should take only a few hours to assemble. The spars are C channels with internal nesting channels forming a very stout but light structure. It attaches to the tail cone with four bolts in a wide bolt pattern to fan out loads. We made adjustable incidence blocks, which we may use to optimize the incidence angle. The chance of that varying between huge differences in engine weights is likely. Special thermal formed tips complete the refined finish.
The Vertical Stabilizer is built along the same lines as the horizontal and also features a nice thermal formed tip. We prefer the ABS tip parts over carbon or glass as they are light, hold up very well, and are much nicer to work with. They also take paint very well, no pin holes and rarely any issues with surface quality.
Lexan doors are stock, and they assemble considerably faster than the current S-20 door. We use .090” Lexan trim strips for the bottom. This material holds up very well and accepts urethane paints. You have the option of leaving the door all clear or painting sections or all of the bottom half.
We are progressing rapidly to a flying prototype. It will fly on the 100 HP 912 ULS, and after obtaining the SLSA status we may swap out that engine for a Titan (depending on when it arrives). A second prototype is also underway which will become our demo showing off the Titan 340 engine.
Stay tuned, things are about to get really exciting. RJS
Outbound Progress Report 16
We have made rapid progress on completing the S-21 Rotax powered prototype. We expect flight testing to begin before the end of the year.
The empty weight came in at 783 pounds. That was with the 10 pound heavier fiberglass cowling, but minus paint, we estimate a common empty weight to be around 820. That will allow for AP and paint.
There has been significant interest in a SLSA version, using either the Rotax or Titan. We believe a Titan 340 version could be around 930 empty. The estimated price could be 180 to 195 K.
We begin flight testing next week and will be sending progress reports as data accumulates.
We are working on this as an option. The structure is suitable for use of flush rivets in most locations.
Stay tuned! More to come soon. RJS
S-21 Outbound Progress Report 15
Cruise Speed and Aileron Testing
On the trip to and from Deland, FL we had ample time to get to know the larger ailerons and the 141 wing. Prior to departure, I bumped up the pitch on the 75” Whirlwind STOL prop to the point that take off RPM was around 4800. This is something I don’t recommend (it is better for the engine to be turning at least 5000+ on takeoff). However, how fast could this wing go with 100 HP and the Raven fuselage? Before departing on a trip halfway across the country I did several speed runs using my phone app to find average Vc. It came out to 116 MPH, which means in level cruise it would be even higher. The trade off was only a small increase in take-off roll. And no loss in rate of climb. The 141 wing climbs great, just let it build speed right after takeoff. The rate of climb was still pushing past 1000 FPM at near gross with the DA at 3200'. We saw no issues with the steeply pitched prop and near gross weight to and from Deland. The demos I gave showed off decent STOL and very impressive cruise speeds. We averaged well over 125 MPH on the trip to Deland, despite not having significant tailwinds. The return trip was a pleasant surprise, averaging right at 115 MPH often into 15 MPH head winds. The extra speed was handy since a winter weather system pushed us west to Texarkana. That is a nice airport, great service, but not without the typical high prices.
Having such fun ailerons kept me smiling the whole trip. During demos it was nice to see the same response from other pilots. The control pressure with the AP is 2 pounds and without it, a mere pound. The larger span aileron also offers more control at low speed, not that it was lacking, and even more confidence in strong crosswinds. Overall, if all Outbounds are rigged properly, the handling of this plane should be something pilots will be very happy with.
The Outbound elevator assembles from a top and bottom panel and a pre-formed trailing edge. The leading edges of the skins may or may not come pre-rolled. If not, is it is a simple task to use a length of PVC pipe and a large flat table to roll into shape. To make this an easy builder task, the skins will be two piece, not one piece, as shown in the photos. The elevator comes with a built-in mount for the electric trim servo and a thermal formed cover. We have provided a large trim tab, so there should be no speed or flap setting shy on trim power.
The ballast weights bolt as far forward as possible to reduce the overall weight gain. 2.5 pounds will be the typical weight to counter balance to 100%.