ORIGINAL: Jim Clousing
Hello Jim Casey,
I have a GP BIG STIK 60 ARF to put together and I will be doing a tailwheel mod during contruction. I also will be adding reinforcement for a rear main for floats. I have a new set of sig floats (41.5" length) and would like to use them on the big stik. I know in a previous thread in 2002 you mentioned the float length for this plane should be 45" nominal. How critical is that difference?
Also, the main gear width in arf kit seems to be less than 25% of the wing span. Before I buy a matching landing gear, how critical is that to the overall success of the float plane?
Jim, thanks for your help in this and any other float topics for this plane.
Jim Clousing
All the float sizing "rules" are guidelines. They have been found by experience to work almost every time.
That being said, Ihave used floats on a light plane that were probably 6" shorter than the guideline indicated. They worked. Alot of the reason for having floats' noses in front of the prop is that it protects the prop when you are beaching. Can the plane nose over?Yeah. Ithink I had that happen once in close to 20 yrs of flying floats.
Float spacing 25% of span:A good compromise between tippiness (resistance to blowing over sideways) and straight takeoff runs. They don't squeeze the floats closer together on clipped-wing cubs. Planes with a lot of dihedral are tippier.
You can cheat one of the float guidelines, maybe two, but when you cheat ALLthe guidelines you're kinda asking for disappointing performance.
But let's review:
GPBig Stik 60: nice plane. Suggest you build it with a flat wing (Take out the dihedral). Stiks have flat-bottom fuselages. If you put on 2 sets of identical landing gear, the float incidence comes out to zero. When I put identical landing gear legs on a H9Super Stik, it was hard to get it to take off. A 3/8 shim in the front gear legs, or a little bit of flaperon will let you deal with that.
Floats too small. The only thing you will probably notice as an annoying shortcoming is pitch instability in the water. Your prop will probably pick up spray when you taxi thru waves. You may damage the prop or the dock when you taxi up to it, or the prop may hit the beach. If they don't have enough floatation, you may find that you push a lot of water up over the Bow. Taxi with full UPelevator. Use a Master Airscrew Black prop. They are the most durable I know.
Sig Floats: (Take this paragraph with a grain of salt. Iam opinionated)
From their website: <font size="2" face="arial">"Built from lite-ply and balsa and pre-covered in SIG AeroKote® using a proven watertight seam overlap technique, the floats are light, strong and perform beautifully. The .40 Class Floats are ideal for aircraft up to 7 lbs (3175 g) </font>"
I doubt if a BigStik 60 weighs less than 7 pounds-especially if weighed after the plywood floats are installed.
Ihave used lite-ply in floatplane hulls. It has approximately the same water resistance as Saltines. AND it grows mold even faster. In my experience, once it got wet it turned into a mildewy paste in a week. If you are really careful not to get the covering on the bottom scratched, they can last a long time. I love SIG and recommend some of their planes as Ideal Floatplanes. Idon't like ANYBODY's plywood floats. Unless you KNOWthat the floats were sealed internally and externally before being covered. be cautious. And Ply floats are going to be heavier than other types. Choices
1)try the floats. See how they work. you could be lucky. (2)Get a good pair of lightweight foam-cored floats from Plane Fun or Seaplane supply. They'll be the right size and they'll weigh half as much. You seal them before you cover them or before you paint them (Water-Based Polyurethane varnish works beautifully as a sealant. Cheap, nontoxic, everything-proof after it dries, does not attack foam with its fumes. WBPUalso works well to bond glass cloth to the float to stregthen them )