Response_to_vendor_potential_specifications.docx

The trailers constructed for NASA and the USMC by this vendor are quite impressive. While those trailers are probably overkill for our current requirements, they provide some useful examples of some of the available options. Below, I have provided feedback on the alternate design options suggested by the vendor (both those that were highlighted and some more general points when comparing the examples to our trailer specifications).

Items that were highlighted in vendor’s inquiries:

NASA trailer:

Since we will be using our trailer for a variety of missions, we have opted for aircraft track mounting points design so as to maintain flexibility in how and what equipment is installed. If similarly flexible attachment rails/systems are proposed, they could be considered.

As for interior cabinetry, the only option that we have considered is the cabinet mentioned in specification item 34 a. that would be positioned over the curbside wheel well and be something like a bookshelf that can be closed/secured for transit.

USMC trailer:

We would consider a trailer with an interior height of 8’ as long as it does not significantly increase the overall trailer cost.

We requested surface mount aircraft tracks with the plan that when we add the under-floor heating elements and anti-static floor covering, that it would result in an approximation of recessed tracks. See option 34 b. in specifications. The channels and e-track in the example trailer do not provide as flexible and convenient mounting of our equipment to the floor.

We do not need the concession style door or awning for our application.

Except during occasional transit between our base and field sites, we will have 120 VAC supplied to the trailer and interior lighting. The only time that 12 VDC would be available is during transit (from the tow vehicle), so at most, a few small 12 VDC dome lights located to provide minimal light in the trailer for access during transit would be considered but would be a low priority.

We do not need the security and recording equipment.

Other items related to vendor’s example trailers compared to our specifications:

Both trailers:

We need to be able to transport our trailer using a large pickup truck rather than a commercial tractor rig. (Also, our limit of 12000 pounds gross trailer weight is so that the combined weight of the vehicles stays under the limit that requires a commercial driver’s license.) Our goal of having maximum payload capacity while keeping within the weight limits will restrict how many of the design features and options in the vendor’s suggestions we can add. (Using a pickup tow vehicle also means that the trailer will need to be mostly self-contained with regard to equipment such as air ride and brakes. E.g. the pickup does not have support for air brakes.)

If our trailer were to be constructed using steel frame members as described in both of the vendor’s examples, would the total empty weight of the trailer be lower than if it is constructed from aluminum frame members? For rigidity of the trailer, we would still need to maintain 16” or less spacing of the structural elements in the trailer box. The closer spacing (12”) of the roof bows as described is favorable. Vendor input on how the trailer weight can be minimized while maintaining a very solid/rigid trailer design is appreciated.

NASA trailer:

What R-value is provided by the 1.5” foam insulation described? Can this insulation also be provided in the floor?

We prefer to have a lower deck height (and overall height) even though this requires having wheel wells within the cabin. It also makes a tandem axle design preferred so that these same wheel wells do not extend as far into the floor area. Additionally, the lower deck height facilitates using only a small stair rather than a full landing/porch a shown in the vendor’s example. However, with the lower deck design, we will not need (or be able to use) the lift gate or under-body storage units.

The doors (both cargo and person types) described seem potentially a good design and appear more secure than a standard door because of the three point locking mechanism. The “door-in-door” design on the back would be useful and saves some wall space in the aft cabin area.

The ladder installation looks suitable to the specification as long as there is enough room for users’ feet to fully engage the rungs without bumping into the body of the trailer. It would also be good if the ladder could extend above the roof edge and/or had removable extensions that would make it easier and safer for personnel to transition to/from the roof.

We did consider the large wall-mounted air conditioner design similar to that suggested, but opted for multiple smaller roof-mounted RV style air conditioners. This arrangement allows us to continue operation if one unit fails, and replacement units are readily available in the field.

We specified the leveling jacks to be mechanical rather than hydraulic to avoid any potential for leaking down of one or more cylinders over extended times. Does the automatic leveling system operate continuously (as opposed to on-demand only), and what accuracy does it achieve?

The electrical distribution in our trailer could potentially utilize a design similar to the one the vendor has used on the wall over the workbench (but would be positioned along the edge of the ceiling as shown in our layout). The larger raceway that the vendor has installed in the trailer could possibly be used if the outlets can be installed in that style of raceway. A recessed power entry panel would help protect the connectors, but it is not clear where this could be positioned so as to not interfere with the main interior spaces in the trailer. How much would the power inlet assembly extend into the cabin?

We have specified interior lighting using high color rendering index (high CRI) LED fixtures in order to provide better quality light and less maintenance than fluorescent fixtures. While conventional fluorescent fixtures can be retrofitted with LED tubes, it would be more efficient to install LED fixtures from the start.

The white fiberglass Kemlite interior lining on the walls and ceiling can be considered, but we would need some information on the antistatic properties of the material. i.e. if an operator rubs along the wall while moving through the trailer, will they become charged up and discharge to the equipment?

We plan to install electric heating on the floor (the open area in the aft cabin and between the aircraft tracks in the forward cabin) before installing any floor covering. Additionally, the floor covering will need to be of an anti-static design. If the vendor can provide this option, we are interested as shown in our specification item 34 b.

USMC trailer:

The general outline of this gooseneck trailer has many of the attributes that we have specified for our trailer and may be a good base to work from. Note that the rounded front top edge of the trailer in the pictures differs from the elevation drawings the vendor provided and would require moving the roof aircraft track in our specifications back to the flat section of the roof.

The storage area under the gooseneck section is similar to our suggested compartment to house the air ride and electric brake systems. Is the compartment that the vendor shows on this trailer completely exterior to the main cabin (i.e. no interior cabin space lost)? Also, would the compartment be large enough to accommodate the equipment we suggest? The recessed power entry panel mentioned on the other trailer might also be accommodated on the front of this compartment (depending on the position of the compartment door). The full-width compartment shown would provide useful protection for the front of the trailer from stones kicked up by the tow vehicle.

The air ride system components described seem consistent to the self-contained design that we are seeking.

The rear frame skid plates and reflective tape in the description seem like useful features.

The step/stair seen (stowed) in the photo seems appropriate to our specifications. Does that unit attach/connect to the trailer when in use? Also, the handrail in the specifications does not seem to be visible in the photos. Where is it installed/located?