Assembling the Tonbo.

As part of the CSO Team’s effort to support Iron Wind Metals website updates, I recently received a copy of the Tonbo Superheavy Transport VTOL, as described in Catalyst Game Labs’ Technical Readout 3085, pages 52-53.

I opened the baggie to find this:

figure 1

The contents included 38 pieces when all were separated from the sprues, making the Tonbo the most complex and pose able Battletech figurine in Iron Wind’s history. I took out my needle files and hobby knife and got to work. No assembly guide was provided in the baggie, such as was included in the recent (and very nice), Omega Battlemech.

The first step was to separate the bits into their assembly groups, so I could tackle the assembly in manageable subassemblies. I used the illustration in the TRO 3085 to help guide me.

The subassemblies consisted of the fuselage, two legs that ended in landing gear, two wings with variable angle rotor/propellers, and four lift hoists.

Fuselage Sub-Assembly

The fuselage consisted of six parts, five of which are pictured below in figure 2 and one, the Infantry bay door, in figure 5

figure 2

The five main parts I assembled by gluing the tail section to the aft fuselage, then those parts were glued onto the main fuselage straight in line with the tail in the ‘up’ position. It is possible with this model to pose it with the tail and after fuselage section bend down a there is a sort of hinge joint in the model. I wanted to show the model as either just landing or just taking off.

figure 3

The nose I thought should be down a little so as to afford the pilot/crew a better view forward and down. The nose wheel I glued into the socket at the front of the cockpit section

figure 4

Then I installed the Infantry Bay Door at the rear underside of the model.

figure 5

Leg/Landing Gear Sub-Assemblies

This assembly consisted of two sets of bogey wheels for the landing gear, upper and lower leg bits, a hip joint to fit into the upper leg, and two ‘feet’ to attach at the base each leg. Note that these two foot pieces are wider than the four similar pieces that are meant to go onto the ends of the lift hoists.

figure 6

Each set of wheels should first be glued by the struts into the four dimples on the side of each lower leg as in figure 7:

figure 7

Then, while that assembly is gluing, take the upper leg and the hip joint and glue the hip into the ‘yoke’ formed by the upper leg. It may be necessary to take some flat faced pliers and carefully squeeze the ends of the yoke together so as to allow the pins in the hip joint to sit in the holes on the inside of the yoke, as in figure 8

figure 8

Next, figure out what pose you want for the legs, whether bent as in the grounded pose, or as I have done, extended as during takeoff or just touching down. Then glue the hip / upper leg into the middle holes on each side of the fuselage as in figure 9, and allow to dry. Note that there is a panel on the outside of the leg that determines how it should look on the finished model, that panel should face outwards on the model, otherwise the lower legs will not match the artwork.

figure 9

Now take up the lower leg/bogie sub assemblies and the two wide ‘feet’. Note how the end of the leg and the foot are each one half of the joint, which when matched together looks like a set of wheels. being mindful of the pose you want, glue the feet into place on the lower leg sub assemblies as in figure 10

figure 10

Once the glue has dried on the fuselage and lower leg sub assemblies, glue the lower legs into the position you want on the upper legs as in figure 11. I used a pillar of modeling clay to hold the fuselage up at the right height to allow the legs to dry in a position under the center of gravity of the model. There is a small hole at about that point on the underside of the fuselage, which can be helpful. I left the model in that position for a half hour, and found the leg assemblies quite stable and capable of supporting the weight of the fuselage. So far so good.

figure 11

Lift Hoist Sub Assemblies

There are four of these, consisting of the upper and lower arms of the lift hoists, the shoulder joints, and the narrow ‘feet’ on each one. among these parts, the narrow ends of the lower arms are where the elbow joint’s are. The upper arms have two ends. It is important to tell which one mates with the elbow joint on the lower arms. The correct ends are cup-shaped next to the elbow joint are pictured in figure 12, the wrong ones in figure 13 have flat ends meant for the shoulder joints.

By the way, it seemed odd to me that all the upper arms seemed to be the same, when I thought there would be a difference between left- and right- sided assemblies. this actually is not a problem as we will see later.

figure 12 and figure 13

First step with these is to glue the joints together at the elbows. Again the actual pose is up to you and can be about anything you want. I chose to model these as helping to support the VTOL as it is taking off or landing. The TRO 3085 illustration makes it very plain that these lift hoists can be positioned very freely. Note that the hoist arms are actually longer, when assembled, than the legs. Figure 14 and figure 15 show the look of the legs as the shoulder joints are glued in place.

figure 14 and figure 15

Now as with the Legs, the feet at the ends of the lift hoists should be glued into place. as in figure 16.

figure 16

At this point your sub assemblies might look like those in figure 17, or somewhat different. (Truth told: I originally assembled the hoists this way, but ended up taking the straight ones apart and re-gluing them as bent in order to achieve the pose I wanted. It’s largely a matter of taste. As these are the parts that allow the Tonbo to pick up and transport ‘mechs, if you want the model posed as lifting a ‘mech, now is the time to pose them in position around the ‘mech. It can be done, but it is a project for another time.

figure 17

Now the shoulders need to be glued in place on the fuselage, prior to attaching the Lift Hoists. Here is where the comment about the legs all being the same ‘handedness’ comes in. The shoulders are one half of a joint, basically a hemisphere on a pin. As is clear from figure 15, each leg has got the left half from a view looking toward the outside of the arm. Therefore on the fuselage, all of the shoulder joints must be positioned with the rounded half of the joint to the right. If this is not clear, see figure 18. This is the only orientation which leads to happiness on this model.

figure 18

Once all the legs are positioned (again the modeling clay to support the model while gluing helps a lot), your model might begin to resemble figure 19. In the background is one of the lift hoists I decided to reposition. The wings are what we will discuss next.

figure 19

Wings and Engine Sub Assemblies

The parts for these include the two wings themselves, two engine nacelles and two rotor / propellers.

I decided to glue the nacelles in an upward, slightly forward canted position as in figure 20, again in keeping with the intention of modeling this VTOL as either landing or taking off.

figure 20

The wings have a ‘yoke’ structure meant to allow the engines to be mounted at different angles, and the underside of each wing has a flat area shown in figure 21 where the flat upper surface of the nacelle fits nicely when the engine is tilted for horizontal flight.

figure 21

I assembled both, using the pliers to slightly pinch the yokes to the pins on the nacelles for a better fit. I saved the propeller /rotor assembly for after the nacelles had glued in place securely. The completed subassemblies are shown in figure 22

figure 22

Final Assembly

Now it is time to put on the wings. Note that this is one of the only parts of the assembly that would not allow an alternative pose as shown in the artwork in TRO 3085. (the other is that the nose wheel does not have a cover to model it as retracted for flight). There was no obvious way to depict the wings and rotor blades as being folded up in the grounded mode. With some experience and skill in modeling, I am sure it could be done, but that sort of work is beyond the scope of these instructions.

Each wing is glued in place securely as in figures 23 and 24.

figure 23 and figure 24

This concludes the assembly instructions for the Tonbo. For tips and hints on modeling this and other models from Iron Wind Metals, check out Camospecs Online at and Catalyst Game Labs Battletech website, especially the fan forums at