Gas Scale and 1/6th Scale.

What's the difference between Gas Scale and 1/6th scale. R/C Boat Company just came out with a 1/6th scale cowling for the 108 Hull which is awesome because I'm getting a 1/8th scale 108 Hull this year. I would love to Have a Gas Scale U13 Gilmore Special and a 1/8th Scale U13 Gilmore Special. I guess the better question would be for Mike at ML. Will the 1/6th cowling work on the Gas Scale Kit or do I need to get the 1/6th scale kit. But he doesn't make a 1/6th scale 108 Hull.

Hi Sam- the cowl that Steve at RC boat company has available for sale is off of our plug. Yes, it will fit the contour of Mike's wood kits perfectly. Steve will also have the 108 hull available pretty soon which he is also building from our plug. The cowl that Steve has fits the "Gas Scale" kit. Stay tuned a little longer and you can get a glass hull from RC Boat company. It's based off of Roger's plans/Mike's kits with a couple of subtle changes to the bottom and sponsons. We tested the plug hull extensively and it works really well.

Fred

So there making a Gas Scale fiberglass 108 hull.

Sam- Yes, it should be available in a couple months. Steve will post it on his website once its ready to go. Fred

Yep. I called Steve today. A gas scale Gilmore to go with my 1/8th scale Gilmore.

To clarify for you Gas Scale is 1/6.667 scale. A 1/6 scale is slightly larger.

While gas scale is 1/6.67 scale, I wonder if many are just rounding down when describing their product or project. I know when I talk to people about gas scale, I say 1/6 not 1/6.67, just easier....

If I'm not mistaking both IMPBA and NAMBA rules overlap enough that the hulls are legal in both organizations?? If I read the rules wrong please let me know?? If the real boat had the drive dog and prop behind the transom Instead of under that's ok.. Seems anything goes motor why's?? It's just in the dimensions of the hull!!!

Later!!

Pat

Hey Pat,

What "the hulls" are we talking about?

NAMBA and IMPBA 1.667 Gas Scale Rules are different and require different measurements.

NAMBA:

All required measurements including the range you can be within, are listed in the 1.667 Scale NAMBA Master hull Roster for each Hull number ever built. NAMBA required that the boats meet measurements of Overall Length, Beam, Maximum Depth, After plane Length, and Tunnel Width. Engine specifications: G or GX Class engines from 15 to 31 cubic centimeters. Ref: Section 21,Page 3, C. Hull Specifications 9. The propeller drive dog may extend one drive dog length beyond transom.

IMPBA:

Only requires the measurements of: "All boats built to a scale of1.8" to 1'0" (1/6.667 scale) plus or minus10% of the beam and 5% of the length."

For your 8910 hull: 31' times 1.80 = 55.8" +/-5% would be within a range of 53 - 58.59" Length Overall. Beam of 14 1/2 feet times 1.80 = 26.1" +/- 1=% or 2.61" - within a range of 23.49 - 28.7".

"The drive dog must not extend beyond the transom unless the prototype's strut and/or drive dog did also." Photographic proof to prove.

"Engine must not exceed a maximum displacement of 31,00 cc utilizing a single gasoline fuel engine with spark ignition and must comply with all IMPBA LSG engine and noise rules"

Here is a specific line items from NAMBA 1.667 Master Hull Roster.

Hopefully this will show the specific differences between requirements of the two Sanctioning activities for 1.666 Gas Scale.

Hopefully my math was correct. CHEERS !!! Bob

There seems to be a little confusion regarding the rules for the Gas Scale Hydro Class under NAMBA rules - Since I wrote the rules I will try and clear up any misinterpretation of them...

First off the Class is called GAS SCALE and only includes hulls that follow the dimensions below. We chose this scale because if we went with a true 1/6 scale a lot of the hulls would end up being to large to meet the NAMBA 60 inch max length insurance rule. There are builders that are using other dimensions that are not part of this class and they should always be called by what they are like 1/6 Gas Scale or a sport class if they are not following the intent of the Scale Class by using painted windshields or adding appendages to cowlings to hide tuned pipes and carburetors.. The best way to think about the Gas Scale Class is that you need to follow all the same rules as 1/8 Scale Nitro with the exception of hull size and engine type. When in doubt about you build please contact your organizations Scale Director.

Below is a overview of the rules under NAMBA and my understanding is that the current IMPBA rules closely match. The original intent was that as the class grows we build hulls that can move from one organization to the other and the manufactures would be able to build one hull that would be legal in both organizations.


NAMBA GAS SCALE UNLIMITED HYDROPLANE RULES

Gas Scale Unlimited Hydroplane racing will follow 1/8 Scale Unlimited Hydroplane rules with the exception of items listed below.

Boats are to be built on a scale of 1.80 inches equals 1 foot of the actual boat (1/6.667 scale).
Boats will measure within the following tolerances of the true scale size, excluding appendages.

Overall Length.................. ± 1 1/4 inches
Beam............................................ ± 12%
Maximum Depth.............................. ± 10%
Afterplane Length (3 point design) ± 10%
Tunnel Width................................. ± 10%

Motor belly pan for motor and flywheel only. If applicable, the dimensions will not exceed five inches in width, nine inches in length, and one inch in depth. The belly pan can not exceed the depth of any riding surface or recovery surface. If the real boat had a full length belly pan, the model must conform.

Engine Specifications G or GX Class engines from 15 to 31 cubic centimeters.

All boats will be models of past or present Unlimited Hydroplanes that are listed on the NAMBA Gas Scale Unlimited Hydroplane Master Hull Roster. The true scale dimensions of any Gas Scale Unlimited Hydroplane will be derived from the unlimited dimensions listed on the Unlimited Hydroplane Master Hull Roster. Gas Scale Unlimited Hydroplane racing rules are intended as a supplement to the general racing rules of NAMBA. In the case of a conflict, the Gas Scale Unlimited Hydroplane racing rules will prevail.

The purpose of the class is to duplicate the unlimited class of hydroplanes as closely as possible. It is the responsibility of the Contest Director to ensure that the spirit of racing an Unlimited Hydroplane boat is enforced. Some examples that may not be allowed include: adding weights to the top of the hull, removing undamaged parts/features, or entering a boat that has not been painted to conceal prior damage.

Boats will be painted, configured, and detailed like the actual unlimited as it ran on the water. The acquisition of documentation validating a paint scheme, cowling configuration, engine configuration, or other scale details will be the responsibility of the boat’s owner. Photographs of the boat are an acceptable form of documentation.

The boat’s engine, tuned pipe and muffler must be concealed within the boat as well as possible while not deviating from scale appearance. Scale engine cowls, fake engines, painted screen, etc. are permitted.

The number of props and rudders will coincide with that of the original full sized unlimited hydroplane. Outdrive units and outdrive engine(s) are prohibited unless the full sized boat after which the boat is being modeled had an out drive or outdrive engine(s), in which case the model must be configured like the full sized boat.

The propeller drive dog may extend one drive dog length beyond the transom.

The boat bottom/sponson profile will be the same general appearance as that of the full sized unlimited hull it represents with the following exceptions:

a. Sponson riding surfaces may be modified.
b. Propeller shafts may be articulated.
Rudders and skid fins may be configured and located as desired.

Boats must meet the following criteria to be placed on the Scale Unlimited Hydroplane Master Hull Roster:

The full sized boat must have been registered with an unlimited hydroplane racing association and the registered boat must have made at least one verifiable test run in the water.

Please contact me if I can answer any questions

Marty

www.pnwta.org

See Bob,

I play in the lines my Winston will run anywhere they run the class!! Just waiting on the mounts and pipe to worry about the rest should be ready for first race next year for sure!!

Later!!

Pat

Looks like RC Boat Company has the gas scale 108 (RC #110) hull on their site:

http://www.rcboatcompany.com/images/RCBoatCompany_part_SG110H-GS_Gas_Scale__6_scale_epoxy_fiberglass_hydro_hull.JPG

whih hull is that from the master roster ?

Tony Jacuzzi said:

whih hull is that from the master roster ?

Click to expand...

newton 108

mhr 7474

dave weagel said:

Tony Jacuzzi said:

whih hull is that from the master roster ?

Click to expand...

newton 108

mhr 7474

Click to expand...

Hey Dave, Have you done any work on your project since delivery? Would like to see progress pics

GeorgiaScaleBoater said:

dave weagel said:

Tony Jacuzzi said:

whih hull is that from the master roster ?

Click to expand...

newton 108

mhr 7474

Click to expand...

Hey Dave, Have you done any work on your project since delivery? Would like to see progress pics

Click to expand...

slowly making progress.

photos to you soon.

What scheme are you planning on? Would love to see pics.

Oi

Just curious, for those doing wood builds, do you put an aluminum skin on the back of the right sponson or no? I know of one that was given an aluminum skin due to the turn fin bracket flexing and smashing the wood. Anyone else having that issue?