Hello everyone!
Today was a big day for the wings--the right wing is finished and ready for aileron and flap installment, and the left wing is right behind it with only about 3 hours of work left to go.
In addition, today we saw the nosewheel and tailwheel go on the aircraft. That's right...we have a nosewheel
and a tailwheel--say what? Well, the Sportsman is a configurable airplane. If built for it in the factory (which we are doing), the airplane can be easily converted from a tricycle-gear airplane to a taildragger in a couple of hours. Configured as a tricycle gear, the airplane is statistically safer to land, maneuver on the ground, and train with in general. As a taildragger, it is better for soft & short fields. Our plan is to fly it initially as a tricycle gear to get accustomed--but the finished product will be a taildragger.
Right now it looks pretty funny, though--it's got a nosewheel, and a tailwheel--but no main gear at all yet. We'll be there soon!!
Today I'm changing it up...we've spent so much time riveting the past couple of days I thought I'd share a little--here's a 20-second video of T"racy" the riveter in action on the left wing skins:
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| We left off yesterday with a wing having clamps all over it. This is the finished product of the cove--at the very corner there you can see the 'doubler'--a thin metal strip in the glued-together sandwich. Adding the extra layer of metal increases the strength where the cove skin meets the top skin. |
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| Today I got to do the interior wing work on the left wing that Tracy did yesterday on the right wing. This is a pneumatic pull-riveter in action waaaay down the aux fuel tank hollow. |
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| This is the last time i hope to see the fuel tanks outside the wing...but if maintenance is required, they are removable. It will take some rivet-drilling and time. The primary tank is up close. You can see the fuel lines (metal piping) in between the main and aux tanks. |
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| Once the fuel tanks are in, then the lines go in. This is one of two vent lines going into the primary tank. The red cap in the upper right is where the fuel line (metal pipe) is about to go. Putting these in required getting a forearm through the 4" inspection holes in the wing...tight. |
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| These are the two vent lines coming out of the wing. The vent system is simple but ingenious. One line simply connects the aux and main tanks; this equalizes the pressure in the two wing tanks at all times. The other line goes from the primary tank out the metal piping protruding from the bottom of the wing. This keeps all venting to a single exit point (instead of one vent per tank). The wing will eventually have a carbon fiber cap on it which will give the wing a clean aerodynamic finish, and also house our Navigation lights, Strobe lights, and Landing lights. It will cover the vent tubing. The electric wire for the lights is coiled up on the right of the picture by the leading edge. |
We also finished the trim tab work on the horizontal stabilizer today:
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| This is the fist pic of our horizontal stabilizer. Bryce is working on the trim tab. Matt is in the background working on our tailwheel. |
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| Bryce ran the elevator trim motor with a 9-volt battery to test the travel limits. we adjusted it to tech order travel with the jam nuts on the pushrod. |
Last, here are a couple of shots of our weird gear configuration!
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| Here's the nose gear hanging on the airplane for the first time. It is not steerable--you have to use differential braking to steer on the ground. |
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| Tracy took this shot of me using a torque wrench to set all the bolts on the nose gear to the correct torque. There are torque-specific bolts all over the plane. Not enough torque and the bolt could back out. Too much and it could shear the bolt. |
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| Here is the tailwheel on the airplane. Unfortunately, we didn't get to do any of the work on this. Putting a tailwheel on the Sportsman requires some fairly detailed fiberglass work to beef up the tailcone structure (which is all carbon fiber). The interior of the tailcone gets fiberglass layering on top of the carbon fiber, which adds strength and better flexibility. Eventually there will be aluminum shims under the leaf springs you see here, helping the tailwheel conform to the fuselage shape and keep impact loads off the tail. |
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| This is looking from above into the tailcone. You can see the fiberglass layup at the bottom of the pic (tail end of plane). At the top of the pic (bulkhead E), there's a massive nutplate with 8 bolts in it, all fiberglassed into the structure. |
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| Here's a closeup of the nutplate. Getting this to the exact right shape to be structurally significant is a challenge...I think that's why we haven't done it yet! |
Okay, that's all 'til tomorrow. It's possible that we might get the main landing gear in tomorrow--but it is Airshow day at Arlington so we'll see. Happy Friday everyone! -zen
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