Deconstructing the Hornet

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I've finally gotten into taking the Hornet apart to begin the rebuild/finishing of the airplane. So far, I've tried to limit the size of the holes cut into the wing structure but everywhere I turn there are more and bigger holes required.

The 3" double Top Flite bellcrank is out and a new laser cut BBQB mount is being made by Kyle to mount the Morris phenolic 4" replacement. Trial fits have been made to determine sizes and clearances.

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The retract mechanism is all out. I didn't think this would be possible, but it worked out. This photo shows most of the stuff mounted inside the wings and nacelles, not counting the retract control components. All of this is scrap. There will have to be new shock gears made with altogether new mounts. Leaving the gear extended changes the design vertical Center of Gravity so the leadouts will also have to be relocated to the bottom of the wing tips. Everywhere, there are more problems which cascade into still more unanticipated new problems.

For now, I'm planning to leave the wing removable but will have to cut into the tail to replace the elevator pushrod because the new one won't be the exact length needed to fit the new 1/8" x 6" flap horn with aligned flaps and elevators.

It doesn't look like props will be a problem but there are still questions about engine rework unanswered.

Altogether, this is going to take months with approximately as much effort as building a complete, but simpler, stunt ship. It took a big act of will to make that first opening in the wing, but, now that its started, work is proceeding well.

Al

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This will be an interesting project to keep track of that is for sure. Keep us posted.

Awesome.

Hi Al,

I am sure you will turn this into a competitive stunt plane.

Big Bear <><
Character: It's what you do when no one else is watching.

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Here are some more photos which illustrate my reluctance to try to make this airplane flyable.

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When it comes to replacing the flap horn on an existing airplane, there is just no way to avoid lots of cutting to get the old flap horn out. The installation of the new horn began with cutting away the trailing edge of the wing to clear the horn and bushings. This took more cutting than is apparent as the original horn was "bowed" around the swept and dihedraled trailing edge. The new horn is straight. This requires removing considerably more material from the center of the trailing edge. The new horn, being straight, also has to be higher in the center of the wing to position the horn ends in the middle of the flaps allowing for the dihedral.

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After enough of the trailing edge is trimmed away, the bed for the new flap horn is prepared. First, the length of the flap horn between the bushings is wrapped with a number of wraps of masking tape to build up the diameter of those exposed portions of the horn wire to a greater diameter than the bushings. The bushings will contact the trailing edge flap horn beds. The masked portions will create clearance with the trailing edge horn bed so that the horn doesn't drag when rotated. The trailing edge excavation is then covered with a liberal application of Super Fil. The horn, with it's masked portions, is covered in Parchment Paper, forced into the Super Fil, and held tightly with a number of rubber bands to imprint the wet epoxy. Nothing sticks to Parchment Paper. This process is exactly like glass bedding the receiver of a target rifle.

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When the super Fil has hardened, the rubber bands and Parchment Paper are removed. The result is smooth, precisely fitting four beds for the bearings, and smooth, 1/16" deep, curved cavities ahead of the bare sections of horn wire.

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Next, the bearings will be epoxied to the wing trailing edge with glass cloth. The horn ends will be buried in epoxy, covered with balsa, sanded to shape and refinished. The newly finished trailing edge around the flap horn will be smooth, strong and attractive when painted. This, with the installation of a new bellcrank, should correct any perceived weakness in the Hornet's construction.

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This photo gives give some idea of the intricacy and amount of labor to design and construct these components of a smoothly functioning retract mechanism working only with hand tools. These six cranks, for example, were cut from 1/16" mild steel with an Xacto tool, cutoff disks, and hand drill. These cranks all assembled using the bolt holes in the ends. The slots in the crank arms aren't functional. They are simply lightening holes to minimize weight as much as possible. Carving lightening holes in steel with an Xacto tool requires dedication. This was probably the most labor intensive control line stunt ship ever built.

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My concept for the ultimate competitive stunt ship was to use retracts and minimum frontal area for aerodynamic cleanliness. The semi-scale Hornet would also have an unusually small side area to minimize the effect of wind on pattern maneuvers while retaining an attractive and realistic appearance. The opposite rotating engines would give smooth, precession free corners and a very high power loading for dynamic performance. The Hornet was small and lightly built with enough wing area give a low wing loading. The flaps were stiff but "springy" due to the weak flap horn. This, as much as anything, probably caused me to have doubts about the airplane thirty years ago and hang it up. I was tired of the effort going into the airplane, I was going to miss the 1979 FAT team trials, and lacked the will, at the time, to fix the flap problem. The retracts didn't weigh much with the batteries used as tip weight. Fixed gears will be nearly as heavy. Finally, the removable wing was a convenience for international shipping. Make no mistake, the Hornet was my concept of the ultimate stunt ship. It was designed to fly well enough to win. Whether it would have flown well enough is debatable, but flying the fixed gear rebuilt Hornet will give a realistic evaluation of the Hornet's capabilities. Dreams of glory die hard.

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Here is one of the engines on its hand cut engine mount mount and carved aluminum exhaust manifold. The mount screws directly to the engine's rear crankcase cover.

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And then, thirty years of storage necessarily involves some damage. There are holes to patch and a new elevator to make. Fortunately, my friend, Bill Wilson, is a master at matching paint colors.

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There is going to be lots of work just on the controls. I tried the new laser cut BBQB style bellcrank mount Kyle made for the Hornet. When I tried mounting it to the rear face of the top and bottom main spars, the front of the Morris bellcrank didn't clear the internal wing mounting blocks. Somehow, the bellcrank must be installed between those mounting blocks. This was the location of the original bellcrank. So I'm back to square one with mounting the bellcrank. I'll think of something, but its a big bellcrank and a very tiny space with almost no access.

There will be lots more fun when its time to install the new flap pushrod on a hidden bellcrank.

Al Rabe

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Hey Al,

I can understand about the worry of a bunch of labor to get it flyable, but look at it this way, you are retired! Take your time, do it right and see how it works. You have nothing to prove with it so you really have nothing to lose. Besides, this is going to be an interesting thread for the rest of us.

Ditto Matt

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Say Ahhhhhh.

Al Rabe

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Al,

I'm following the "resurrection" of the "Hornet" with great interest. Appreciate your taking the time for the pictures and post.

Where do you buy Parchment Paper....is that a standard Office Depot item?

TIA

Cheers.

Warren Wagner

Its a standard Kroger item for baking cookies.

Al

Do you have any plans or drawings for the aeroplane ?

I have some drawings, enough for me to build from, but probably not enough for anyone else to reasonably duplicate the airplane. Thanks for asking.

Al

>
>Its a standard Kroger item for baking cookies.
>
>Al

Get in trouble from the Mrs. for stealing her baking supplies?


Great thread, and awsome pictures, makes for great reading at the end of a mission day!!