2005 Serpent 12 Rigger Project

[Eric Perez]

Here is a link to my current project.

https://www.intlwaters.com/gallery/thumbnails.php?album=159

It's my third-generation small-block rigger design. I'm still in the final stages of construction. Just need to bolt on the hardware and do the usual detail work to get it sea worthy!

At my current pace I should have this thing in the water in a week.

Hope you like it.

 

[TomMoorehouse]

Here is a link to my current project.
https://www.intlwaters.com/gallery/thumbnails.php?album=159

It's my third-generation small-block rigger design. I'm still in the final stages of construction. Just need to bolt on the hardware and do the usual detail work to get it sea worthy!

At my current pace I should have this thing in the water in a week.

Hope you like it.

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alright! come on Eric, make it a kit! I need some competition!

 

[Watercadet]

Wow that is short! How is that SG shaft conversion working for you? Did you have to sleave the clutch nut to get the flex hex fit snug?

Adam

 

[Don Templeton]

Eric,

Great looking boat! But how are you gonna see it on the pond with such dull colors. :lol: :lol:

 

[jayt]

That looks great Eric! However, it is awfully big and heavy compared to an A SAW rigger I looked at a few weeks ago....talk about small and light - it was smaller than my 4-cell rigger and made from some black-colored stuff.....

 

[Eric Perez]

Wow that is short! How is that SG shaft conversion working for you? Did you have to sleave the clutch nut to get the flex hex fit snug?Adam

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Actually the shaft's OD is 5mm. I just used a 5mm to .130 smooth bore coupler like the one's the battery pushers run on the SPEED 700 motors.

I just took the 5mm IPS shaft on the traxxas motor and ground a flat on it. I "lube" the flex-hex with red-loctite and tighten everything down. I've ran a couple of gallons with this setup and I have not had any failures.

To remove the flex-hex I just heat it up with a torch and the loctite lets go. I then pull the assembly off.

I guess that a regular SG shaft engine wouldn't be any different it's just a tad longer than the traxxas IPS.

 

[Eric Perez]

Eric,
Great looking boat!  But how are you gonna see it on the pond with such dull colors.  :lol:   :lol:

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I figured, if they mistook my dead boat for a Bouy, it could actually lengthen it's service life. It's no fun when you get run over by a gasser :angry:

Seriously, when my little riggers get to bouy 4 all I can pick up is the roostertail

We don't use the stand at our monlthy club-races so it's hard to spot 24" of balsa wood on the course.

By the way that's not paint on the outside of the boat...

 

[Don Templeton]

If not paint what is it? Tinted epoxy?

 

[anthony_marquart]

It's polyester covering,... like for airplanes!

If not paint what is it? Tinted epoxy?

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[Eric Perez]

It's polyester covering,... like for airplanes!

If not paint what is it? Tinted epoxy?

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Yes, that is correct. The boat is laminated on 3-sides with sticky-back MonoKote. They sell it in 5X36 sheets. Fuel proof and water proof a match made in heaven. I did my entire boat in a couple of hours.

Check it out: https://www.intlwaters.com/gallery/displayimage...cat=10064&pos=2

Here is the link to towers site for the material:

http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXHY06&P=0

Specs:

NOTES FROM OUR TECH DEPARTMENT

Top Flite has designed this sheet of Neon Yellow Trim MonoKote to be used

on airplanes, cars and helicopters. MonoKote Trim Sheets allow you to create

brilliant designs and your own special color scheme.

INCLUDES: One Trim MonoKote Sheet- Neon Yellow

SPECS: Width: 5" Length: 36"

FEATURES: Pressure sensitive adhesive backing (for easy application)

Fuel proof and waterproof

Permanently bonding, and conforms to curves and contours

COMMENTS: MonoKote Trim Sheets may be matched with MonoKote, LusterKote Paint

and EconoKote Film

MonoKote: TOPQ0703 LusterKote Paint: No Match EconoKote: No Match

REQUIRES: Scissors (HCAR0670) 4/22/98sk

ir/jl

UPDATE JMM 2/5/03

 

[Eric Perez]

Project Update:

https://www.intlwaters.com/gallery/displayimage...lbum=159&pos=22

I got the boat almost ready to go in. Just need to bolt on the turn-fin and add the fuel. ran a couple of tanks throught the engine last weekend to help the break-in and the engine was responding well to carb adjustments.

Got some club racing this weekend so I should atleast have some MPH numbers to share with you next week.

The build went well and I'm happy with the way the way it came together. I hope that the performance is there...

I noticed that the carb works a little better with a litte extra back-pressure, so I added an extra-long stinger to the pipe. I'm not sure if you can see it in the picture but the stinger is held on with a set-screw. It's very easy to swap out the stinger for a different length to fine tune the back pressure.

If you are running a 6.5mm ID carb the extra back pressure may come in handy.

 

[Don Templeton]

Eric,

Looks great and very light! What engine do you have in it? I'll be waiting to see how she runs. By the way, how long is your tub?

Don

 

[Eric Perez]

Eric,
Looks great and very light! What engine do you have in it? I'll be waiting to see how she runs. By the way, how long is your tub?

Don 

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The boat is really not as light as it is "bright". I think that it came to 3 pounds and a few ounces. With 4 oz if fuel I think it will be in the 3.3-3.5lb range.

The engine is a Traxxas TRX2.5 air-cooled with a pull-start. I've got the same engine in my cat with pull start but it's water cooled. I've got a water cooled version with no pull-start on my FF12. So far I've had good results with the traxxas engines they appear to be real tough, I've ran as much water as fuel through these things and they seem to hold up to the abuse...

I experimented rasing the exhaust timing on the cat and had good results. After I base-line my rigger and get it setup I will probably modify the engine and keep track of the changes.

The tub is 22-1/2" long. It's about the same length as the FF12 tub.

 

[Don Templeton]

I can't figure out why your boat weighs that much. Are you sure? Looks like you've used a bunch of balsa and 1/32 ply. What are the side, top, bottom and bulkheads made from?

Don :huh:

 

[Eric Perez]

I can't figure out why your boat weighs that much. Are you sure? Looks like you've used a bunch of balsa and 1/32 ply. What are the side, top, bottom and bulkheads made from?
Don  :huh:

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The tub sides are 1/8 balsa laminated with 1/16 ply. The top is (2) layers of 1/32 the bottom is 1/32 with extra layers under the engine.

The spoons are wood covered foam. sides are 1/8 balsa with 1/16 ply the sides and bottom are 1/32 the top is 1/64.

I'm using FULL size radio equipment in the boat, I haven't had great luck with cheap mini-micro servos in my riggers. The lineup is a JR standard servo for the throttle and a ball-bearing Hi-Tech standard for steering.

I ran the boat this past Saturday and it worked well. Not a speed demon, but it seemed to handle chop and wind just fine. The boat turns well and the engine responds well to throttle input.

I launched with a V937 which is one of the fastest props for small-block riggers... if the hull takes to it. My boat had a little hop with the V937 I will continue to work with the setup it looks promising.

I also tried a 1440 and a cut down S220 boat ran fine. Did a couple of runs with Y537 as it was easy on the engine.

I will continue to work with the engine and pipe -I just don't seem to be getting the RPM's that I need. I'll take it easy as the engine is still fairly tight.

 

[TomMoorehouse]

I can't figure out why your boat weighs that much. Are you sure? Looks like you've used a bunch of balsa and 1/32 ply. What are the side, top, bottom and bulkheads made from?
Don  :huh:

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The tub sides are 1/8 balsa laminated with 1/16 ply. The top is (2) layers of 1/32 the bottom is 1/32 with extra layers under the engine.

The spoons are wood covered foam. sides are 1/8 balsa with 1/16 ply the sides and bottom are 1/32 the top is 1/64.

I'm using FULL size radio equipment in the boat, I haven't had great luck with cheap mini-micro servos in my riggers. The lineup is a JR standard servo for the throttle and a ball-bearing Hi-Tech standard for steering.tight.

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sounds like you built it too strong. you could have used 1/64 to sheet your balsa. But I really don't like balsa tub sides. they just crack at bad times. My ff18 will have 1/8 3 ply with giant holes cut out to make it light. Then it will be sheeted on the outside only with 1/32 ply. This is very light..... and untested (untested in nitro but has worked well in electric). The ff12 has just 1/8 3 ply tub sides. They work well. The top and bottom can easily be 1/32 ply. Joes hardware is a TON lighter than the speedmaster. It looks like you used the .505 tubes...... they are way overkill. They use them on gasoline riggers. I know, I know.... I used a little on my ff12 as well... but I know better now. I designed the ff12... geez 5 years ago. The FF18 uses the .335 tubes with a .414 joiner. A lot lighter. I have also had my share of micro servos go bad, usually at a race Did you use mini servos?

 

[Eric Perez]

What's up with all the sad faces?

The main problem of the previous prototype was that is was running too light on the water. The Serpent seems to have fixed that problem -the extra weight appears to help the boat out. I also like the smoother feel of full size servos. The throttle seems to be more linear now, when I adjust the idle speed I can see the engine change RPM with every beep of the radio.

I think that I will continue to make the boats larger and wider as it tends to promote stability like the japannese riggers. The next tub will be full 26" long, I think this is closer to a full .21 rigger size.

Anyone have some rough dimensions of competitive .21 class riggers?

 

[TomMoorehouse]

sad faces?

ff21 tub length is about 27 inches... it is smaller than most

 

[Don Templeton]

Sorry Eric,

I just thought it looked like it would be much lighter than mine and maybe you were weighing it on a bathroom scale.

Tom,

I guess they make everything bigger in Texas! :lol:

I know what you mean Eric, I don't like to build throw away boats for SAW either and there is much to be said about a little extra weight and strength for heat racing.

Don