Seabee Sport/F3A Pattern

Out of the box, and the Seabee seems to have survived it's trip to Barbados well. No damage of any kind is visible, and everything appears to be in order.

The fuselage is complete with even a pilot, sitting under the canopy. There is a well-made fibreglass cowl, pre-painted, and looking much more robust than any ABS part ever could. Everything looks sturdy and well made. Wheelpants are supplied, and will be fitted for the photo-session, but if they fall off later, I won't be too worried about refitting them. There is a substantial hardware pack.

And best of all, the model is not covered in nasty, sticky-backed vinyl! It appears to be a regular, heat-shrink covering, very MonoKote-ish indeed! Hurrah! How did this happen? Did I misinterpret the information I found on the net? Or is this simply a somewhat newer, and improved version of the Seabee? Either way, I am considering it to be a positive discovery!

Servo mounting blocks (with servo-lead notches!) are supplied, and after removing the covering from the large servo-arm slot, the blocks are CA'd to the inner face of the servo hatch. I used new Hitec HS-311 servos for this job.

Thankfully, and unlike the Fokker, there was plenty of room in the bay. No fettling of wood was required to get the servo and tray to fit, and the servo did not touch the inside of the covering on the top of the wing panel.

This shot shows the servo and cover-plate, sitting on the wing next to the bay itself. Mounting screws have not yet been drilled and fitted. Note the string (doubled) to be used to pull the servo lead through to the wing-center.

The servo will actually be mounted with the servo arm on the far side of the bay, with the arm to the trailing edge (rightmost) edge of the wing. Obviously then, this servo is the wrong one for this wing-panel! :-)

Interesting: Note the wing-rib, visible inside the servo bay. There are pieces of wood cut/broken out from between the lightening holes in the rib. Inspection shows the same thing in each wing-panel, yet all the other ribs appear to be unbroken. I assume this is in some way connected with running the servo wire to the root. Not that it matters, since the designer might just as well have called for one, large lightening hole instead of a series of smaller ones. The structure of the wing is quite strong despite the missing pieces of wood, because I checked. And in any event, the ribs of a wing are not heavily stressed.

The wing-panels were joined with 30-minute (2-Ton) epoxy. The joint uses a conventional, flat ply dihedral brace/joiner. Interestingly, this joiner is perfectly straight! No dihedral?!??

Rubber bands were used to keep the joint closed while the epoxy cured. The bands between the wing-mounting dowels is obvious, but if you look closely you will see additional bands being used at the trailing edge of the wing. The rectangular hole mid-wing is where the aileron servo leads will exit the wing structure. You can also see the opposite ends of the pull-through strings seen in the previous photo.

The blue stripes on the wing panels do not align! This is a flaw in the covering, not in the alignment of the wing at the join. But it will not be noticable. The actual join itself will be covered by a strip of trim-tape. In any case, the upper surface of the join (as shown) will be inside the fuselage when the aircraft is assembled.

Uh-oh!

When I cut away the covering from the stab slot, I immediately noticed a nasty crack in the join between the two fuselage sides! This is very surprising, because so far, the quality of the kit has been looking good!

I mean, I can understand how this happened. Down there under the covering is a pre-cut slot for the bottom hinge of the rudder (yet to be attached). This slot obviously extended itself right into the stab slot. But it should have been picked up and repaired in the factory

It was easy enough to fix. A couple drops of CA and a clamp for a minute or two, and the problem was fixed. But this should'nt have happened. I know it is an inexpensive kit, but that flaw should have been spotted in the factory. You can see how obvious the crack was, in the last photo. The wrinkle in the covering seen in this photo, caused by clamping the two sides back together, indicate that the covering was applied after the crack appeared. It should have been glaringly obvious to whoever did the covering. For them not to react to it doesn't say much for quality control!

I'll be keeping a sharp eye out from now on.

Okay, the stab is in place with 30-minute epoxy, and aligned. I checked the alignment several times with a thread, maintained at a constant tension/stretch by a weight on the free end. Checking the diagonals to the front and rear corners of the stab-tip, then carefully wiping away the excess "squeeze-out" epoxy with alcohol, before checking again. The best part was when the epoxy oozed down between the sub-trailing edge of the stab and the elevator joiner wire, threatening to make the elevator a fixed portion of the stab! Good thing I noticed that... :-)

Well, here is an explanation for the cracked fuselage rear. When I offered up the fin/rudder assembly, I was surprised to see the position of the lower hinge of the rudder, vertically, on the stern-post. After cutting away the covering and preparing the slot to accept the hinge, I took this photograph. You can clearly see that the hinge is displaced upward from the center. The distance from the top of the hinge-slot to the notch for the elevator joiner (the nice, shiny wire visible at the top of the photo) is only about half the distance from the bottom of the slot to the bottom of the fuselage. This offset may be necessary to accommodate the attachment of the steerable tail-wheel assembly, but it should have prompted for extra caution during construction of this part of the fuse.

Here is the fin/rudder assembly, attached with 30-minute epoxy, and this is a first for me. Usually, you either mix too much epoxy, or (worse) you mix too little of the stuff! But this morning, I mixed up *exactly* the right amount. (Now, I can die and go to heaven happy!) I put some PJ in the lower hinge to prevent the epoxy from locking that tight, so a sneaky droplet tried to bond the LE of the rudder to the TE of the fin. Expecting this, I was ready with an alcohol-soaked thread to slip through the hinge-line and clean things up!

This was a beautiful joint. The pieces went together perfectly, alignment was 100%, the end of the fin ligned up with the end of the fuse exactly, and the fit was snug. With the fin pressed firmly down, even the front strake was a perfect fit on the top of the fuse! If only it were always like this!

The main gear is now attached to the fuse. This model ises two, independent leaf-spring struts, one for each side of the aircraft, held in place with two bolts per side. I'd have used Nylon bolts, but I have no idea where to find 4mm Nylon bolts around here, so maybe I'll change them later, if the bolts ever surface.

This photo also gives a look at the canted engine mount. The engine will be positioned underneath this mount with the head down and to the left. This position is to allow the exhaust to fit into the tunnel visible at the bottom of the firewall, under the mount.

Notice also the streamlined booties on the wheels. These are fibreglass, and look fairly well made, but like all booties will probably be troublesome. When that happens, I suspect they will be coming off!

This model was supplied with 2-1/4" wheels with foam tires. I replaced these with balloon wheels of the same size. I also have larger balloon wheels that I may add if/when the booties come off. They will make the ship look a bit yam-footed, so I will see how she handles the grass with the smaller wheels.

One thing about the gear -- the parts supplied were not quite suitable. Washers and spacers and collars in abundance came with the kit, but they still didn't allow for the wheel to be properly spaced along the axle, in the boot. And of course, assembly was taking place on Saturday evening, with no hardware store open until Monday.....

The tailwheel assembly was simple and straightforward, and I liked one feature in particular. Instead of the inboard end of the wire being poked into a hole in the rudder (which can threaten the integrity of the wood structure of the rudder) it is attached to the bottom edge of the rudder with two clips that are attached by screws. Alas, again, I have to visit a hardware store on Monday! Each clip requires two 6mm screws (one for each side) and the kit provided one 12mm screw. No biggie, but for a couple of cents, I'll make the correction.

Observe this photograph of a part of the firewall. Part of the engine mount is visible, as is one machine screw bolting the engine to the mount, and the head of another screw bolting the mount to the firewall.

Just to the left of the mount, is a pre-drilled hole that is supposed to carry the throttle pushrod guide-tube. This guide-tube (white) is just visible protruding from the hole. The hole is patently too large for the tube. Cyclops could see that, even after the argument with the pointy stick! I had to whittle a tight, hard balsa plug and glue it into the hole, then re-drill it to suit the diameter of the guide-tube. This was a trivial task, but it's exactly the sort of mistake that I should not be faced with when building an ARF. But once again, I remind myself that this model cost me less than $100.....

Here we are again, at the opposite end of the throttle pushrod guide-tube (just visible in the bottom right corner of this photo).

Notice the beautifully laser-cut (you can see the blackened edges) throttle servo mounting bay. Unfortunately, the curved turtle deck is located immediately above this bay. (Remember, we are underneath, looking up.) When the servo was offered up to the bay, the bottom of the servo was touching the inside of the turtle deck. To tighten up the mounting screws would most probably have lead to a cracked turtle deck.

Two 1/8" lite-ply shims were made up. When these were glued into place, the throttle servo fitted with a hairs breadth space to spare.

Here we see the throttle servo installed and the throttle pushrod connected. The shims (described above) are glued in to place and fit so well they look like a part of the original design!

This photo shows the elevator (left) and rudder (right) servos. I installed them exactly as recommended and now I regret doing it their way. As it stands, the two pushrods extend backward directly under the two wing-bolt blind-nuts. This means that the bolts will have to be trimmed to the correct length to avoid fouling the pushrods. This is no real trouble, except it is one more thing that has to be done correctly if difficulties in flight are to be avoided.

If I had mounted the two servos furthur apart (and there was plenty of room to do so) and run the white servo arms inward, then the oushrods would have travelled between the wing-bolts with plenty of clearance, and any length of bolt could have been used safely.

Well, I'm not going to change it now! I'll just have to carefully trim my wing bolts to the correct length!

Now this is very bad! The little glitches that I have found in the kit so far have been nothing in comparison to this!

The trailing edge of the wing has been drilled to accept the two wing-bolts that bolt through into the fuselage to keep the wing in place. These two holes are obviously mis-aligned. I've tried one hole alone, and then the other, and it appears that it is not a case of one hole being wrong. They are both incorrect. There is no way to get the wing on, and expect it to be true and square to the model! These holes will have to be filled and re-drilled accurately (not easy to do with the model at this late stage of completion).

Dammit! The weekend staring me in the face, and my drilling machine is on loan! Grrrrr!

To get the wing to fit straight, I had to butcher the two wing-bolt holes, as can be seen here. One was enlarged, but the other had to be elongated quite a bit. Eventually, the wing could be fitted straight. When this stage was reached...

A 1/16" aircraft-grade ply plate was fashioned to locate the nylon wing-bolts. This was epoxied to the bottom of the wing where it also protects the bottom surface of the wing from wear and tear associated with the fastening and unfastening of the wing.

It is small and inconspicuous, but in any event it will be completely hidden when the belly-pan is attached later.

Now, the oversized holes are filled with a light, epoxy putty. While this is soft, the wing was bolted into place (with correct alignment double-checked), and then unbolted again. Waxed paper was used to prevent the putty transferring from the wing to the fuse, and onto the wing-bolts themselves. This photo shows a roll of waxed paper still in one of the holes.

When the putty cures, the surrounding area can be covered with masking tape (to protect the covering material) and any excess putty sanded away.

Ths belly-pan was attached with 30-minute epoxy. The access holes in this component had to be elongated to allow the heads of the wing-bolts to be reached by the driver that will be used to attach and detach the wing.

I don't know why this aircraft uses two shades of red (or red and orange) instead of one shade of red. In any case, you can make out the contrast between the belly-pan and the underside of the wing itself.

You can also make out the port servo-bay cover, with the servo and control rod in place, and connected to the horn on the aileron surface. Silicone tubes visible dangling from the firewall area will connect to the fuelling dot and to the muffler pressure nipple.

I dislike externally mounted switches, and avoid them where ever possible. Not only are they subject to exposure (fuel residue and water) but you also have to cut a large hole in the skin of the aircraft, which can only tend to weaken the structure.

Here you can see an internal switch-plate that I have constructed. It fits across the fuselage, just in front of the elevator/rudder servo bay, and is keyed into the side of the aircraft. A small actuator made from a plastic-covered paper-clip allows the switch to be operated through a tiny hole in the side of the fuse. You can just make out the wire loop that will remain outside the fuselage.

The ELE and RUD servo leads snake forward (up) through a hole in the switch-plate to the Rx which will be installed later. The antenna can also be seen passing through a plastic guide on the left side of the photo, and down through the same hole in the switch-plate. The flat area above the plate (where the charging pig-tail is coiled) is actually the underside of the cockpit floor. The aileron servo leads exit the wing (when fitted) in this area, and connect to the extensions from the Rx. There is enough room in this area for a 4-cell flat-pack to fit, if the CoG needs shifting rearward.

After a 10-day wait :-/ this 1/2" spacer arrived to extend the exhaust manifold. I can't think of any 40-ish sized 2-stroke that would fit on there with a standard muffler. A 4-stroke muffler would have been easy to fit, but then the throttle pushrod hole (and servo) would be in the wrong place.

I'll probably cut two gaskets from sheet-copper to 'soften' the join between these components.

Here you see the secret to a well-cut cowl: Colour-coordinated tools! :-)

Using masking tape to protect against tool-slippage and to take the markings, the cut-out for the cylinder is made with a small hand drill. Electric drilling would be of no real value. Two to three turns on the handle and you are through the shell of the thin fibre-glass cowl.

The cowl is very tight on this aircraft; there are four cuts to be made. On top of that there will have to be ventilation holes (both in and out) made.

Here is the finished cowl. Neatly cut, no jaggies. Not bad

The large circular opening to the right is for the thrust-washer and spinner cone, and came pre-cut. Moving left is a smaller circular opening for the carburetor air intake. On the upper curve of the cowl, is another, smaller circular opening for the needle-jet adjustment. The large, squarish hole on the left is for the cylinder and head. You can just make out the large slot underneath the cowl that allows the exhaust baffle to exit the cowl. This leaves a large gap beside the baffle that, together with the channel/slot under the fuse allows for hot air to escape the cowl. With the head and half the cylinder mounted externally, and the other half of the cylinder receiving airflow from through the carburetor opening, no additional cooling vents should be needed.

Other than minor adjustments of fit during preliminary flights, no furthur work should be required on the cowl.

With the aircraft fully assembled and ready to fly, I hung it in a home-made balance-rig to do a final check on the Center-of-Gravity. The CoG will always lie directly under the point of suspension, and a plumb-bob hanging from the same point will show the exact location of the CoG on the airframe.

Incidentally, the aileron control-horn/pushrod linkages can be seen, and so can the hot-air vent under the cowl (next to the muffler. You can probably just make out the antenna exit point near the tail, just below the elevator pushrod (don't forget the aircraft is upside down!).

Apprentice modeller and trainee pilot, Dotcom, observes and assists in the balancing process.

Dotty reminds me that the recommended CoG location is 110mm from the leading edge of the wing, plus or minus 10mm. He advised that since a forward CoG increases stability, while a rearward CoG results in increasing aerobatic manuverability through increased instability, I might want to err forward rather than rearward, at least for the first few flights...

Thank you, Cadet Dotcom!

On a piece of masking tape, I marked the recommended 110mm CoG location, along with the maximum forward (extra stable) CoG limit, and the center-line of the model. (Stand on your head to read the markings.) The plumb-bob which is hanging about 1/8" clear of the belly-pan, indicates that the CoG is within acceptable limits, biassed slightly towards stability, and dead on the center-line.

This puppy is ready to fly!

This is a photograph of the little guy who will be sitting in the cockpit when I take this aeroplane aloft. Heh! He looks a little aprehensive, wouldn't you say? I wonder why? Surely, accounts of my piloting skill can't have reached Vietnam, where the Seabee (and presumably this pilot) originates?

Come to think of it, this guy looks a little like our David!

Here's another look at the little man! This photo highlights the weak point in the structure of the fuse, where the wing-saddle approaches the cockpit side. There is only about an inch of fuse there, holding the front onto the back. I don't think there is any doubt about where it will break, if it ever decides to break! And here am I, trying to learn how to land a tail-dragger on this airframe! :-/

To be fair, it is quite robustly constructed. There are 1/8" plywood doublers on both sides, and the entire cockpit floor is also a single, plywood sheet. This forms a strong, ply channel to bear the loads. The sides are also of 1/8" hard balsa. So providing I don't do any one-point landings (with the point at the front), I should be OK. Still, if it had been me, I'd have used a couple of side-panels to the cockpit, making for a deeper side in this area and a recessed cockpit floor. Anyway...

You can also make out, just behind and below the pilot's left shoulder, the external part of the wire pushrod that actuates the on/off switch. The dangling wires are an aileron-servo extension (left) and the charge lead (right).

Looks sweeeet! Here's hoping she flies sweeeet too! :-)

Despite the problems with the mis-drilled wing-bolt holes in the wings, I think this model has turned out OK, and worth the $99 that I spent. It remains to see, now, how well it behaves in the air, and how well it stands up to the rigours of transportation in my little car, and to the even greater trials of my poor flying!

As usual, I'm nervous as all of hell....

It's sleek, and probably fast, even with only a .46 onboard. I've programmed a bit of flaperon, which should hopefully allow me to flick a switch and lower my approach speed. I can add a bit of deflection to the elevator as well, if dropping the flaps causes a change in pitch.

One thing I'd suggest to anyone contemplating a Seabee of their own: Consider a 4-stroke motor up front. That should make it considerably easier to get the exhaust routed out through the channel at the bottom, without having to buy extension manifolds, etc. A 4-stroke will probably mean you have to re-think your throttle linkage, but that is doable.

I was having a hell of a time fueling the aircraft with the cowled fuel-line. When I tried fueling through a third tube fuel spouted out through the carburetor and all sorts of nasties.

So I decided to fit a fueler valve, and manufactured this little bracket to carry it. There isn't a lot of room under the cowl, which accounts for it's somewhat funny shape.

Here's the fueler in place and piped up. A small hole in the cowl to allow the fueler probe to reach, and the problems I'd had with fueling simply disappeared.

She's flown!

Conditions were poor, and photography was difficult, but here is a shot of the Seabee in flight, making a low pass up the strip. Only minor tweaking necessary, and the aircraft returned home in perfect shape. Everyone says she looks good and moves fast, and I sorta agree. More flying photos to follow!

I shouldn't have spoken so fast!

With the Seabee now smashed to smithereens in the middle of her seventh flight, it is obvious there will be no more photos to come. So here, in the dim light of her first flight on a rainy day, is another look at the Seabee in the air.

This photo was taken just before the 7th and final flight of the Seabee.

I was making gradual headway with this model, with the engine starting to run reliably and the trimming out of the control surfaces almost to my liking. My comfort level was also increasing, and I was starting to feel at home in the sky with the model and handling it much better.....

Then it had an argument with an Acrowot with half-ounce glass epoxied onto the wing on top of the obeche.

About a foot of the right wing, plus the entire right aileron sheared off, and fluttered away into the bush, not to be seen again. The aircraft span around, and headed for the clubhouse. For a moment I thought I might be able to direct the crash away from the spectators, using the elevator. But with the left wing lifting and no right wing to match, she started to corkscrew down quite violently. I throttled back, and watched her go in right at the edge of the strip, just opposite the club.

As this photo shows, impact with the ground finished at the fuselage, what the Acrowot started on the wing.

Everything as far back as the cockpit was crushed and broken into a series of tiny pieces. This thing was going at full chat until just before impact, so you can believe me when I tell you it hit hard.

This photo was taken after the engine had been extracted from it's grave. It took two people to get it out.

The pilot looks unharmed, but from the canopy forward, the whole fuse is matchwood. That hole at the left is where the spinner had buried itself. The force of the impact ripped the manifold off the front of the muffler, so that is a write-off. The tank was crushed like a concertina, with a neat round hole punched in it by some piece of wreckage; maybe a mount-bolt. The metal engine mount was busted to pieces. Thankfully, the radio gear seems to have survived undamaged.

The Acrowot, BTW, had a small chunk taken out of the wing, and had it's engine fall off, to dangle by the fuel lines from the front of the fuse. The change of CoG made the aircraft unflyable, and after a heroic attempt to save the model, she went in, but dammage was not too bad, and she may fly again.

Oh well. Shit happens. She was nice while she lasted, and I wish she'd lasted a bit longer, but that is all part of modeling.