Zeus Scale F-18, F-22, Eurofighter Wheel Conversion Kit Freewing 90mm EDF

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Zeus Scale Jet Wheel Conversion Kit
Summary

This item allows the conversion of the scale wheel set from the F-18, F-22 or Eurofighter for use with the Freewing Zeus 90mm EDF. Print files from one of the scale designs are also required to complete the Zeus wheel set. The Zeus requires modification to the scale wheel sets due to the mechanical actuation of the main landing gear doors and the size of the nose wheel.

Designed for use with Dave Brown Lite Flite tires (Mains 2.75", Front 2.5"). The tires are low bounce, low noise and light weight compared to other low bounce tires. They reduce shock to the landing gear which improves durability on rough runways or when landings are less than perfect.

Overview

Replace the OEM wheels with printed rims and low bounce tires. This kit includes ONLY a front wheel rim, the inner hub for the main rims and a main gear door lever bearing. The printed tools for these components are also included. Additional components are required from the F-18, F-22 or Eurofighter wheel sets to complete the conversion for the Zeus.

The Zeus requires modification to the scale wheel sets due to the mechanical main landing gear doors. A lever on the gear door uses with the main wheel to close and open the door. This conversion kit changes the shape of the main wheel in with the lever, to be similar as the OEM wheel. A gear door bearing was added to reduce friction between the tire and the lever. This should improve the reliability of the door closure. The front rim s a 2.5” diameter wheel.

Mechanical landing gear doors sometimes require adjustments. The Zeus design includes several adjustment features. It is recommended to install, test and operate the OEM main landing gear prior to ANY modification (upright, upside down and during flight). When the wheels are changed, adjustment may be needed.

Bill of material

1) Printed files and tools for one of the scale wheel sets. Main wheels only.

• F-18 (link)
• F-22 (link)
• Eurofighter (link)

2) Printed Zeus Front Rim G5.1.3MF (or .STL)
3) Printed Zeus Main Inner Rim Z4.5.3MF (or .STL)
4) Printed Gear Door Bearing G5.12.3MF
5) Brass tubing OD 3x ID 1.5mm, 2 pieces ~ 15mm long AliExpress
6) Piano wire 1/16” diameter, 2 pieces ~ 23.5mm long
7) Main tires - Dave Brown (DB) Lite Flite 2.75" 1 pair (WH27-5527 ~$9/pair)
8) Front Tire - Dave Brown Lite Flite 2.5" - 1 tire (WH25-5525 ~$8/pair)
9) Clear Gorilla Glue (non-foaming) or similar ductile adhesive compatible with filament selection

Recommended Tools

1) Same Tools as the Scale Main Wheels call for in the F-18, F-22 or Eurofighter
2) Zeus Sand and Clamp Tools.STL
3) Drill bits 1.4mm and 1.5mm
4) Sand paper ~600grit and ~150grit

Build Steps

Main Wheels

Follow the assembly guidance from the scale wheel set and substitute the main rim inner hubs with the Zeus version provided here (Zeus Main Inner Rim Z4.5.3MF).

Front Wheel

Reduce the width of the FRONT TIRE ONLY from ~19mm to ~17.5mm. The goal is to narrow the tire so it does not rub on the nose gear strut. Sand both sides evenly. Service wear will reduce the tire size, so do not overdo it here. Assemble the tire into Tire Sanding Tool. With light to moderate pressure, use course sandpaper ~150 grit, to remove a little from each side. Use the tire tread as a guide for material removal. A sheet of sand paper placed on a flat surface can work well. Alternate sanding both sides of the tire until the width achieved. Your goal is to keep both sides relatively flat and parallel. Periodic cleaning of the sandpaper & part with vacuum increases the cutting rate and surface finish quality.

Assemble the front wheel. Insert the tire on the outer side rim and press the rims halves together until they click into place. Seat the tire on the rim by pulling/pressing the tire around the circumference. The rim is designed to compress the tire, so pressure is needed to make the assembly.

Precision drill the center bore to fit the axle into the wheel assembly. I used an electric hand drill at a very low speed (~30 rpm). Start with 4.0mm and then repeat with 4.1mm bit to get the final diameter. Clearing the plastic from the flutes of the drill bit after each use improves the quality of the successive hole in thermoplastics.

Test fit the wheel to the nose gear. If the tire s the nose gear strut, perform additional sanding to narrow the tire. Minimum recommended front tire width is 16mm.

Front Wheel Assembly

Repeat the Front Rim & tire assembly per above with adhesive. I used a thin coat of adhesive on all the surfaces of the rim t. Use a toothpick to spread a film on the ing surfaces of both halves. Avoid excessive adhesive which could get into the axle bore as this could come into with the Clamp Aid.

The wet adhesive acts a lubricant so the tires may separate the rim halves. Keep pressure on the rims while setting them into the Clamp Aids and a clamp device. With the tire assembled, use the Clamp Aids and a clamp ensure the rim halves are properly seated while adhesive cures.

Bonding the tires to the rim is not recommended. The tires are very flexible and it's difficult to judge if the tire is centered/round on the rim. As long as the tire ID is centered and the tire is free to move on the rim, you should be able to get them into round after the adhesive has cured.

After the adhesive has fully cured, precision drill the axle bores with a 4.0mm then 4.1mm bit.
Test fit the rim assembly on the axle/aircraft.

Gear Door Bearing Assembly

Prior to making any changes, take photos of all the main gear door points of adjustment. If you run into difficulties, this allows you to find ‘home.’

The gear door springs are fragile and can easily fall off the ‘fixed’ end (blue side). With a toothpick, apply a tiny dab of hot glue or similar on the blue side only. The goal is to reduce the likelihood of that side accidentally falling off. You should not need to remove the spring and it’s a PITA to reconnect.

Precision drill the printed Gear Door Bearing s to fit the 1/16” piano wire. Cut the 3mm brass tube and piano wire to fit in the bearing s. Assemble the brass tube and wire. Lightly sand the bearing on the side which will the tire. The outside of the brass tube should be just flush with the plastic.

Slide the Gear Door Bearing assembly onto the door lever arm. It should go on fairly easy. If you remove it, the door lever arm so that the lever is not dislocated from the hinge point.

Installation

Install the wheel in same fashion as the OEM wheels. You may find the Zeus scale wheels work fine with the main gear doors alone or with adjustment to the door connectors.
If you find the wheel gets caught on the lever or the door does not fully seat when closed, installing the Gear Door Bearing assembly should help. If the issue persists, review the photos for my adjustment settings on the gear door. Making similar adjustments may resolve the issue.

My Zeus works in any orientation both with and without the use of the Gear Door Bearings.

Test the gear and door operation prior to flight in multiple orientations (eg upside down, right side up, plane held sideways)

the tire ODs are round & concentric to the center hole. Adjust as needed by pulling/pushing the tire. It need not be perfectly round. Runout of a few millimeters is adequate.

3D print
ASA filament or similar