Skeg fins for 1/4 scale boats

[edge540_freak]

Hey guys, I am building a 1/4 scale crackerbox from plans but it doesn't say how big the skeg (turn fin) is supposed be. I made one already that is about an 1 1/4" high but it looks a bit too small. Any suggestions would be much appreciated. :)

[drakonis]

hmm 1/4 scale huh. i would think in the 2-3 inch deep range might be more appropriate. thinking more along the lines of the 3 inch. thats a big boat whats the length? beam?

[Kmot]

This is a 15' long Crackerbox:

http://www.glen-l.com/designs/inboard/inboard-images/dsn-cbxa2.jpg

The hull depth is 28". Based on that info, I would say the skegs look to be about 10" high, so 1/4 scale would be a 2.5" skeg.

[edge540_freak]

thanks for the imput guys. really appreciate it. the length is 50" and the beam is 18". I've heard they are lots of fun to rum especially the 1/4 scale size!!! can't wait to get it in the water!

[edge540_freak]

kmot, I'm guessing you know quite a bit about the real crackerbox boats, tell me if I'm wrong, but what's ur opinion one running with a one or two fin skeg? which is better and why?

[Kmot]

I don't really know much about the c-box other than I dig them. :D

I have a set of plans for a 1/4 scale and I also have a fiberglass 1/6 scale hull.

Most of the photos I have seen have had the double skeg. I think for the realism factor that would be the way to go.

[Hoghappy]

I have one each (1:10 scale) and the one with the shorter twin fin seems to side slip/hop some like a NASCAR race car through the turns and the single deeper fin allows for better cornering making mine stick in the turn like a Formula 1 race car.

There is a thread about these here: http://www.rcgroups.com/forums/showthread.php?t=851484

Crash

Tom that boat needs finished!


(Ok...I added some scale pics and be sure to check out the video links at the Crackerbox thread for some cool racing.)

[edge540_freak]

yeah my dad said the single fin is better for corning which makes sense and since this is my first boat build, I'm not gonna be very picky on the realism factor especially since it's just gonna be for fun when I actually have time to run it. Hopefully, more often than I expect :) I'm plan on making the skeg removable in case I want to try different ones later. thanks for the imput all.

[Kmot]

Formula 1 boats with dainty little outboards turn like Formula 1 cars with dainty little engines.

Crackerboxes with big honkin' V-8's turn like NASCAR cars with big honkin' V-8's.

It's the natural order of things. :p

[xx29l9]

I don't really know much about the c-box other than I dig them. :D

I have a set of plans for a 1/4 scale and I also have a fiberglass 1/6 scale hull.

Most of the photos I have seen have had the double skeg. I think for the realism factor that would be the way to go.

Hey Tom,
Now your talking my language...nice 426 hemi sitting in there!!! That would be a fun ride!

bob

[Hoghappy]

Formula 1 boats with dainty little outboards turn like Formula 1 cars with dainty little engines.

Crackerboxes with big honkin' V-8's turn like NASCAR cars with big honkin' V-8's.

It's the natural order of things. :p

And let me add that the one with the twin fin is the more fun of the two...you hold your breath on every turn wondering if the next hop is the hospital hop! :p

[woodybob]

Perhaps this will help, the complete crackerboxbuilding story. (http://images.google.com/imgres?imgurl=http://www.2brothersrc.com/powerpete/skegs.jpg&imgrefurl=http://powerpete.20megsfree.com/photo3.html&usg=__bXOoYE9DWdOMQClcGlGLxCnewcc=&h=960&w=1280&sz=145&hl=en&start=16&um=1&tbnid=VfzdJo5vSMlPfM:&tbnh=113&t)

[edge540_freak]

well hopefully sometime in the future I'll have the money and the time to build a real crackerbox and race it.

[BOZINATOR]

The good old days:cool: :cool: First of all a 2" x2" aluminum 1/8" thick was what was used by the orginal builder, My friend and neighbor, :cool: Gary Johnson back in the early 90"s. Too deep and the boat will flip in the corners and cause drag in the straights. Too short...and it dances down the straight away (looks cool though:eek: ) Between the both of us we built about 50 boats out of door skins and teak 1/4" strips. The tops were covered with 3/4' wide iron on strips (like used in cabinet making) with thin pieces of model rail road wood for the grout line. The whole boat was fiberglassed with .75 oz cloth using the west systems epoxy from west marine.:) We ended up using zenoah g-23 from BH Hanson (strong :eek: ) and are made for racing...with tuned pipes and headers.

Be sure to check the chine steps from side to side...if they are not equal....your boat will do things un expected.

No,...I am not forgeting Jerry Dunlap. Gary and Jerry were best of friends. Jerry drew the plans and published them at Garys request to promote cracker box racing world wide.

jim:)

[edge540_freak]

thanks jim, really appreciate your input and advice on the skeg fin. I made one today that is 2 1/2" long and 3 1/8" deep. Hopefully it will work out great and I made it removable so I can interchange fins if needed :)

A good, knowledgeable friend of mine who has been in the boating world for years was telling me that I should extend the stuffing box tube an inch out the bottom of the hull and NOT to curve it at all. What is your recommendation on the stuffing box tube installation?

[Ghost 2501]

turn skegs don't need to ne THAT big due to the density of the water, all they need to do is put a proportion of their size in the water, a combination of model's speed, density of water you are sailing in, and latteral accelleration from the deflection of thrust do the rest to swing the boat around.

[edge540_freak]

Does anyone know where I can find a set of plans for a 1/4 scale shovelnose?