PylonWorld

I've acquired the molds for Jerry Small's Swee' Pea / Sky Baby and will soon be making them available once again. The kit was originally a fiberglass and foam kit, but molds were made for the wing and V-tail to build it as an all composite.

I will be producing these for sale after building, testing, and refining a few things. The price will probably be around $250. One thing I'm going to do is build a jig for mounting the tail, and it will be pre-mounted. This will increase the shipping cost some, but will assure easy assembly.

Here are some photos.

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Fuselage molds

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Tail molds

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Wing mold - tip

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Fuselage and tail - side view

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Here is the plug for the new Swee' Pea tail.

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This is the parting plate for the new tail. It is resting on top of the parting plate fixture for The Smasher..

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Here is the plug in the parting plate fixture:

QM40

With all due respect, why would you bring back something that in today's standards is " old technology"? If I remember correctly, Chip was flying this plane a while back and was quite successful,but then again he could fly a Aspire EP glider to a respectable time. The demand was down even when this plane was new... I question your reasoning behind this... but I also wish you luck selling it...

PylonWorld

The molds were available, so I acquired them. It allowed me to start working with composite wings and tails in an expeditious way.

The wing on the Swee' Pea is almost the same airfoil, if not exactly the same airfoil as the Sidewinder. But the wing is a little shorter than the max.

The plane was known to have tricky takeoff and landing habits. At the 2002 NATS, Jerry spent some time with me talking about his airplane designs, both successes and mistakes. One thing he mentioned was that he believed the Swee' Pea Takeoff and Landing habits were because the tail was too small. I gasped when he told me the stab to wing area ratio on the Sidewinder.

So I'm making a new larger stab to see if he was correct. In terms of current technology, the Swee' Pea was one of, if not the, first all molded composite Q40. All reports I've had about the plane is that it was almost, if not, as fast as anything going today.

Even if I only use them for my own foray in Q40 and practice flying, the molds were very worthwhile.

And thanks for the wish of luck on selling them (not my primary, or even secondary goal) ... the price point may make it an attractive way for others to take the Q40 plunge, however.

DHG

My Feedback: (7)

Don,

In another thread you mentioned that you may add a sub-fin and/or rudderlet to the Swee'Pea in addition to increasing the tail area ... both changes for the better, IMHO.

I've made Swee'Peas in both Q40 and F3D size, using Stinger fuselages. They had the sub-fin à la Art Chester's later (improved) version of the Swee'Pea II/Skybaby, and a little extra area in the V. Both were very fast and very well-behaved on takeoff. One top-name flyer even asked me some probing questions about my F3D version, since his V-tailed Stiletto had a nasty habit of torquing around to the left on takeoff and trying to eat his caller. I suggested he might want to add a sub-fin, since that was the only visible difference between the two, and I knew that vertical tail area below the thrustline would tend to yaw the airplane right instead of left. He did, had no further problems & proceeded to kick my butt with it.

That's gratitude for ya.

Duane

PylonWorld

Duane,

You are a wise man.

One reason The Smasher has a slightly higher than normal tail is so that a ventral fin can be placed below the thrust line. In fact, the tail junction is 1 inch above the thrust line and the end of the bottom of the fuselage is 1/8" below the thrust line, and the top is 1 1/4 above the thrust line. I will be tuning the size of the ventral fin as needed.

But I still have a secret reason for using rudderlets. Every pilot can use all the help he can legally get, don't you think?

PylonWorld

This is the primed and finished parting plate for the tail.

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This is the finished parting plate with the tail plug in it. The next step is to put moldeling clay around edges and put the tail in. Then the clay will be trimmed. A good coating with PartAll PVA and the mold making will begin.

Note that my low resolution camera makes the plug look thicker than it actually is. The actual tail thickness is 1/4".

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This is the first side of the tail mold. It has not been trimmed yet. The plug remained in the mold, probably because I had the whole deal in the curing oven overnight and the modeling clay that was used to hold the plug is place was soft. This is the best situation, because you don't have to worry about getting the plug back into the mold perfectly. The mold will be trimmed, waxed, and a good coat of PartAll PVA will be sprayed on. Then I make the other half.

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This is the modeling clay in the parting plate. The clay held the plug in place and filled any voids between the parting plate and the plug.

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The new tail molds. They will have clamping holes drilled around the perimeter of the tail so that they can be pulled tightly together when the two halves are joined. One side will be tapped so that nuts don't have to be used.

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Another shot of the tail molds. This tail will make a good tail for Quickies as well as the Swee' Pea. In fact, I have a Predator that needs to be assembled and I'll probably put one of these tails on it.

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The new tail molds together.

On the first side, two of the layers were six ounce fiberglass mat. It took a lot of resin to wet the mat out. I used the same number of layers, and the side with the mat came out almost 1/16 thicker than the side with just cloth. So, even though it is hard to wet out, the mat really builds up the thickness. I'll be using more mat on future molds.

The "gelcoat" layer for these molds was WEST SYSTEM 105 resin with 209 hardner, which is the slowest in that resin/hardner family with a pot life of 40 minutes, and a cure time of 24-48 hours. Cabosil and graphite powder were mixed into the gelcoat. The Cabosil makes the mixture thixotropic (less runny), and the graphite is used as pigment, plus it helps to make the mold better releasing.

The layers of cloth were put on with 105 resin and 205 hardner. The 205 hardner is fast with a pot life of only 9-12 minutes. So, you have to work fast, and batch it, when doing multiple layers in one layup. The benefit is that you can make the mold more quickly. 4 hours between layups without a curing oven and 2 hours with a curing oven.

The molds now need to be sanded, compounded, and polished. They will then be treated with FreeKote 700, which is a non-migrating mold release. The nice thing is that parts don't come out with wax on them.

PylonWorld

The molds were ready, so patterns were made for the skins and the fiberglass. I always make patterns so I can quickly cut out fiberglass on a cutting pad with a Fiskars rotary knife ... watch those fingers. The patterns are made from 1/8" Baltic Birch plywood (cheap, only $6 for a 24" x 48" sheet) with printouts of the part attached with 3M77.

Here are the patterns.

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Here are the prepared materials.

The tail skins have been cut out, and the edges and the hinge line beveled. The CF is .007" x .5" x 7.5". The outer cloth layers are 2 oz, the inner are .7 oz. There are two piece of CF tissue for the center of the top and bottom up in the right corner.

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Here is the top after the layup.

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Here is the bottom skin after layup.

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Here is the top with porous release film placed over the fiberglassed area. The bottom also gets release film. The film has tiny holes in a grid pattern, so that excess resin can be pulled away.

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A breather strip is run down the bag. The molds are covered with paper towels to act as breathers and to absorb excess epoxy.

Here everything is in the bag on a table and the vacuum has been pulled.