BullAnt Gozunder Power Bogie System

A New Concept in Under Floor Power Trains

The BullAnt Gozunder Power Bogie puts yet another extremely useful tool in the modellers' toolkit. An extension off the main bogie layshaft is fitted with a Universal Joint cup section to enable a drive shaft to be connected to the bogie below the floor of the model.

The photo series above shows a pair of HO gauge bogies with 18mm wheelbase, 9.6mm disc wheels and bogie centres of 120mm. The motor is a Mashima MHK-1020, and drive to both Gozunders is via a pair of telescopic Cardan Shafts. The Gozunder bogies have additionally been fitted with the press-stud mounting system attached to 26mm cross bolsters. The acrylic chassis, for demonstration purposes only, is 3mm thick, and the motor/gearbox combination only intrudes into the cabin area by 3mm, or less than 1/8".

With an 80mm wheelbase, the Gozunder bogies can rotate approximately 11-12 degrees maximum, which would allow them to negotiate a 202mm or 8 inch radius curve.

Hollywood Foundy offers a Telescoping Cardan Shaft Kit to provide the connection to an under floor motor or transfer box. Because the bogie drive connection is off the end of the bogie, a telescoping connection is necessary. As the bogie rotates, the shaft changes length by a small amount, and the telescoping shaft provides for this action.

The Telescoping Cardan Shaft may be connected to a range of gearboxes or transfer boxes to suit the Mashima 10 Series or 16 Series motors. The bogie gear reduction ratio is 15:1 and may be coupled with a 10 Series gearbox with an additional 1.8:1 reduction, giving a final drive ratio of 27:1.

A gearbox for Mashima 16 Series motors provides an additional 2:1 reduction, giving a final drive ratio of 30:1. A simple 1:1 Transfer Box for the 16 Series motors can be fitted that keeps the final drive ratio at 15:1 for faster models.

The BullAnt Sidewinder gearbox can provide a total underfloor solution. A powerful 10 Series motor coupled to a 1.8:1 reduction gearbox, giving a 27:1 final drive ratio, and room to fit a flywheel!

All The Usual BullAnt Options

Of course the Gozunder comes with all the ordering options of a BullAnt, multiple gauge choices, 2 or more axles, many wheel sizes and the largest choice of wheelbases available from any supplier.

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How to Order..

Option: Number of Axles

The Gozunder can be supplied with 2, 3 or 4 axles. In theory, there is no reason why it could not be supplied with more axles, however the design does not allow for any movement or compensation and this could limit the ability to track curves and points.

A standard Gozunder is two axles and the option choice automatically defaults to to a 2 axle version. To choose a 3 or 4 axle unit, scroll down the arrow on the 'Number Of Axles' box and click on the number of axles of your choice. Additional axles cost extra because of the additional wheels, axles, gears, pickups etc. The additional amount is shown next to the option.

However, a word of caution, the Gozunder design provides a rigid wheelbase, there is no lateral movement on the centre axles. This can be a problem with 3 axle configurations where the axle spacing is large and/or small radius curves are employed. A rigid frame of any length can de-rail on corners and sharp points. It is not really possible to advise a minimum radius that the Gozunder will handle as it is totally variable according to wheelbase, wheel size and wheel profile.

We do offer, on the other hand, an option that provides a lateral action on the center axle. With this method, the center wheels have a slightly narrower back to back measurement and employ a nickel silver wheel housing and thinned down wheel bearings. The worm gear is also slightly thinned as well and this combination means that there is 1.3mm of lateral movement on the center axle only. Because of the additional time taken in the assembly of this option, there is a price premium charged.

Option: Wheel Size & Type

The Wheel size selection box is mandatory for all BullAnt products. The first option for wheels is: '0 Wheels, Please do not fit wheels -($6.00)' The reason for offering the Gozunder without wheels is to suit those modellers who want a different wheel type to those offered by us. You will receive a discount of AUD$6.00 for not having wheels fitted.

By choosing a Gozunder without wheels, you will understand that we cannot test the Gozunder prior to shipping, other than basic operation, and we cannot fit the pickups. The axles are 2mm diameter and can be removed from the Gozunder by gently prising the bottom half of the gearbox housing off. The gears will be greased at the factory and the wheel bearings oiled. The pickups will be supplied in the package but not fitted. Because the phosphor bronze pickups are brittle, please make any bends in the pickups gentle. One spare pickup will be supplied in case you learn this lesson the hard way. Just to give yourself an idea how much bending they can take, make a small bend at the extremity of the contact finger and see how many times you can change the angle of the bend.

Initially we will have a somewhat limited range of wheel sizes available, but over time we will be constantly adding new types as we find the demand for them. All our wheels conform to the NMRA RP25 wheel profile, and are hub insulated on one or both wheels. Solid disc wheels are made from machined nickel silver, while spoked wheels have a moulded Delrin centre and either nickel silver tyres or chemically blackened brass.

Wheel sizes are quoted in both metric and imperial (inch) measurements, the inch measurement is in brackets.

The wheel choice is quite descriptive, '9.6mm(.378") Code 88 NS Disc' means an RP25 profile wheel of 9.6mm or .378 inch diameter with a tread width of .088" or 2.24mm, as a nickel silver solid disc wheel. This wheel might also be described as a 'Code 88' or 'finescale' wheel. Normal tread width for most HO wheels is Code 110, meaning that the tread width is .11" or 2.79mm.

We have the ability to produce solid disc wheels to your specifications, the minimum run is 500 wheels, call us for a quote.

To help with choosing wheels sizes, the table below equates the available Gozunder wheel sizes in millimetres to the actual wheel sizes in inches. Sizes are provided for 3 of the popular scales.

OO Scale 1:76
HO Scale 1:87
TT Scale 1:120
20 1/2"
28 1/4"
27 1/2"
37 3/4"
25 1/4"
28 3/4"
45 1/4"
31 1/2"
49 1/2"
37 3/4"
34 3/4"
39 3/4"
54 3/4"
56 1/2"

Option: Track Gauge

At present we offer the Gozunder in 9, 10.5, 12, 14.2, 16.5, 18.2, 18.83mm track gauges. These gauges are also listed as their common gauge such as HOn3, TT, HO/00, EM, P4 gauge.

Please note that while we do make mechanisms to 9mm gauge, we do not make these items to N scale. The 9mm gauge is offered for modellers who require a narrow gauge in a larger scale. In many cases, these mechanisms may be too large for N scale.

We may add to this range as demand dictates. Every gauge added to the list requires different length axles and jigs to assemble the wheel sets with the correct back-to-back measurement. If you want a gauge that is not offered, please email us and enquire, we may be able to help.

Option: Wheelbase

This box is mandatory for all BullAnt products. The wheelbase is the distance from the centre of one axle to the centre of the next. You should simply type a number in this box corresponding to the desired wheelbase, acurate to the nearest 0.25mm or .01". You can enter the wheelbase in metric form as eg: 22.5 or in inches as .886"

If you have chosen aGozunder with more than two axles, type the first axle to axle distance, then a + symbol and then the next distance, and so on. The axles can be at different spacings if you wish, but please make sure the wheel sizes do not cause an overlap. The Gozunder gear box will be at the start of the specification, so if you typed 20 + 30 +40, then the gearbox will automatically be placed at the 20 end.

The minimum wheelbase is 15.5mm. for a 2 axle unit. If you specify a wheelbase less than 15.5mm, we will not be able to complete your order and will contact you.

The table below shows some popular wheelbases in feet and inches equated to the scale size in millimetres. Conversions are shown for 5 of the popular scales. The resultant wheelbases have been taken to the nearest 1/4 millimetre as this is the accuracy we work to.

OO Scale 1:76
HO Scale 1:87
TT Scale 1:120
3' 6"
3' 9"
4' 0"
4' 3"
4' 6"
4' 9"
5' 0"
5' 3"
5' 6"
5' 9"
6' 0"
6' 3"
6' 6"
6' 9"
7' 0"
7' 3"
7' 6"
7' 9"
8' 0"
8' 3"
8' 6"
8' 9"
9' 0"

Option: Mounting Bolster

With this option, you can choose the size of nickel silver bolster for mounting the Gozunder to your model. There are two types of bolster, a cross mounting and an end mounting, and you can order any type as swiveling or fixed. There are, in addition, three sizes for each bolster.

The plain bolsters on the left are the cross mounting versions and the 3 on the right are the end or cantilever mount versions. The cross bolsters have had the side fold removed to make it simpler to mount the Gozunder, but the end mounts retain the folds. The mounting holes are all 2.0mm diameter and the spacing between the two holes on the end mount versions is 3.5mm. The mounting hole centres for the 20, 26 and 32mm cross mounts are respectively 17, 23 and 29mm. The distance from the bogie mounting hole to the centre line of the end mounts for the 26, 32 and 38mm end mounts are respectively 22.9, 28.9 and 34.9mm.

The 26mm end mount is suitable for Gozunders with wheelbases up to 38mm, the 36mm mount suits wheelbases up to 46mm and the 38mm suits wheelbases up to 50mm. The Press Stud mount may be added to any of the bolsters shown.

You also have the option of having the bolster swivelling, which would be the normal case, so the bogie can rotate in the model, or fixed. The fixed option has the bolster attached (soldered) to the spine section so it does not rotate. This option is quite often used where the unit is fitted to a fixed wheelbase model. Note that each bolster option has the choice of swivelling or fixed.

Some modellers will prefer to have extra fixed bolsters to make the attachment to their model easier. If this is the case, please leave us a note in the comments section of the order.

Quantity & Select Fields

To the right of the Product Option column, there is a quantity field that defaults to one unit, so if you wish to order more than one Gozunder of a given specification, enter the quantity in this field. The Select field must be clicked to order the product, and will display a tick. You can de-select the product by clicking the Select field again. You can also order a dummy unit at the same time by filling in the fields and selecting the dummy.

To order a Gozunder of a different specification, click on the 'Order Selected Products' button at the bottom of the page and you will be shown the contents of your shopping list. Then select 'Continue Shopping' to order a Gozunder of a different specification.

The shopping cart page also gives you the ability to calculate the cost of your purchase to date in other currencies, there is a link to X-Rates under the summary box.

Local Taxes - GST

Australian purchasers must pay the Goods and Services Tax, it is included in the price. Overseas purchasers do not pay this tax, and it will be automatically deducted from the price if you indicate you are an overseas customer.

Checking Out

As part of the checkout process, we first need you to tell us your details so we can contact you if there is a problem with your order and also where you are so the program can calculate the shipping cost. There is a box on this page that allows you to enter any special notes or requests for our attention.

By clicking on 'Continue', the program will calculate the cost of freight and the next page gives you a number of choices as to which freight method you want to use.

You then see a further summary page showing the total price payable, with shipping included and, if you are an overseas customer, the GST component deducted.

Finally, you will be given the choice of method to pay, and if you choose credit card, you will be passed through to e-Way, our payment gateway provider.

If in doubt, call us...

We are happy to discuss your requirements with you, so either send an email to the address shown on the 'Contact Us' page, or telephone us on +61 3 5629 1100. Please check your time zone though, we are in Eastern Australia and do not like phone calls in the middle of the night.

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