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Convair Model 61 CJ805 Powered 39.4 m version Updated 3D Print 1:150 Scale

Model Overview & Print Notes

Summary

Convair Model 61 CJ805 Powered Updated 3D Print 1:150 Scale

Additional Note: Only the display stand files are provided here as free downloads.

The aircraft model itself is available separately through my Gumroad page https://creativedesigns840.gumroad.com/l/hwcnt

Or you can visit my main Gumroad page on https://creativedesigns840.gumroad.com

Convair Model 61 — The Twin-Jet That Could Have Challenged the DC-9

Concept Overview — A Twin-Jet Convair Successor

The Model 61 was envisioned as a twin-engine turbofan airliner using the CJ805 turbofan series, derived from the Convair 990’s powerplant lineage. In contrast to the four-engine Convair 880 and 990, the Model 61 sought to achieve:

Lower fuel burn
Reduced maintenance cost
Improved dispatch reliability
Competitive economics against short- to medium-haul aircraft such as the DC-9

The T-tail configuration, inspired directly by the DC-9, positioned the Model 61 as Convair’s true narrow-body market response, optimized for high-cycle regional and trunk-route operations.

This design direction mirrors what Douglas later achieved with the DC-9, and McDonnell Douglas with the MD-80 series — scaling a proven airframe into a long-term product family.

Airframe Geometry — Shortened Convair 880 Lineage

Based on available three-view references and CAD interpretation of Fuselage shortened to ~87.5% of Convair 880 length, Approximate fuselage length: ~34.5 m, Structural weight reduction, at the cost of lower passenger capacity, T-tail layout, requiring careful center-of-gravity and pitch stability balancing

Despite the shorter fuselage, the Model 61 appears longer than the Convair Model 60, due to T-tail geometry and aft horizontal stabilizer placement, extending the effective tail moment arm.

Wing & Aerodynamics — Proven 880M Platform with Modifications

A key design philosophy was reuse of the Convair 880M wing and wingbox, minimizing development risk while retaining Convair’s high-speed cruise aerodynamic DNA.

Wing Data (Inherited & Modified)

Span: 36.58 m
Root-Tip Airfoil: NACA 64-0012 - NACA 64-0008

Aerodynamic Adjustments

Wing sweep and wingtip geometry modified to compensate for:
- T-tail moment arm changes
- Modified CG envelope for shortened fuselage mass distribution

Unlike the Convair 880M and 990A, the Model 61 relocates engines to the rear fuselage, similar to the Sud Aviation Caravelle, altering:

Pitch coupling behavior
Yaw inertia
Structural load paths
Maintenance accessibility

Powerplant — CJ805-23B and the Hypothetical CJ805-41C

The baseline engine assumption is the CJ805-23B, producing approximately:

71 kN thrust per engine

A later conceptual upgrade suggests a fictionalized CJ805-41C, estimated at:

~74.73 kN thrust per engine

Performance Gains

Improved takeoff performance
Better hot-and-high airport capability
Increased payload margin
Improved thrust-to-weight ratio

Estimated Thrust-to-Weight Ratio

Using CJ805-23B engines:

T/W ≈ 0.23 - 0.24

A strong value for a 1960s–1970s twin-jet, comparable to DC-9-class performance.

Weight & Fuel Capacity — Downsized but Efficient

Estimated Maximum Takeoff Weight (MTOW)

Metric: ~60,312.61 kg
Imperial: ~133,000 lb

Due to fuselage shortening and reduced internal fuel volume, total fuel capacity is lower than the Convair 880 — reinforcing the Model 61’s intended role as a medium-range, high-frequency narrow-body.

Cabin Layout & Passenger Capacity Estimation

The Model 61 retains Convair’s 5-abreast (2+3) seating layout, preserving a comfort advantage over 6-abreast competitors.

Seating Assumptions

Seat pitch: 33 inches
Cabin layout: 2+3
Fuselage reduction: ~5 m shorter than Convair 880

Estimated Passenger Capacity

~85–110 passengers, depending on configuration
Trade-offs include:
- Lower empty weight
- Faster turnaround times
- Improved seat-mile economics

CJ805 Era — Early Stretch Program

Variant	Plug Extension	New Length
Base CJ805	—	39.4 m
CJ805-41C Stretch 1	+1.0 m forward +0.5 m aft	40.9 m
CJ805-41C Stretch 2	+2.0 m forward +1.0 m aft	42.4 m

Goal: Increase seating and revenue while remaining engine-limited.

based on MTOW estimation

Variant	Length	Estimated MTOW (kg)	Estimated MTOW (lb)	T/W (Ratio)
Base CJ805 (38.0 m)	39.4 m	60,312 kg	133,000 lb	0.24 (CJ805-23B)
Stretch 1 (39.5 m)	40.9 m	63,500 kg	140,000 lb	0.24 (CJ805-41C)
Stretch 2 (41.0 m)	42.4 m	66,000 kg	145,500 lb	0.23 (CJ805-41C)

What will you get?

This bundle content included 3-aircrafts of Convair Model 61 with CJ805-series engines installed.

Pack A — 3D Printing Pack (STL + 3MF)

Get Convair Model 61 CJ805 powered 3D Printing Pack Here for $13

Includes:

High-resolution STL of the aircraft
Included Custom Aircraft Stands
Clean watertight mesh suitable for resin or FDM printing
3MF file for layout reference
Aerodynamic, smooth loft surfaces just like wind tunnel models
Ready for slicing (Cura, PrusaSlicer, Bambu Studio, Orca-Slicer)
Optional: scaled versions (1:150, but can be re-sized as 1:72, 1:144, 1:48, etc.)

Perfect for: Collectors · Modelers · 3D printer hobbyists

Pack B — RC Maker Pack (DXF + 3MF)

Get Convair Model 61 CJ805 powered RC Maker Pack Here for $18

Includes:

Full DXF cross-section slices (wing + fuselage) for laser cutting
Up to ~50 fuselage stations
Wing rib sections
Clean orthographic section cuts
3MF file for RC layout reference

Perfect for: RC aircraft builders · Laser-cut foam/balsa makers · Workshops

Pack C — Engineering Pack (CAD)

Get Convair Model 61 CJ805 powered — Engineering CAD Pack Here for $23

Includes:

Full STEP 214 file (solid bodies + surfaces)
Full IGES file (solid bodies + surfaces)
Full CATIA file (solid bodies + surfaces)
Full Parasolid Binary .X_B (solid bodies + surfaces)

Complete aircraft with precise NURBS lofts Suitable for:

SolidWorks
Fusion 360
CATIA
Creo
Siemens NX

Engineering-grade geometry

Perfect for editing, CFD pre-processing, and derivative design work
3MF file for layout reference included

Perfect for: Engineers · Students · Aerospace researchers

Pack D — Merchandise Art Pack (DXF + DWG + PDF)

Get Convair Model 61 CJ805 powered — Engineering CAD Pack Here for $10

Includes:

Clean line-art views:

3-side view (top, side, front) + Bonus 1-side view (belly)
Isometric view
Provided in DXF + DWG + PDF

PDF in both modern black-over-white diagram as well as negative-white-over-black diagram High resolution, ready for:

T-shirt designs
Posters
Stickers
Wallpapers
Classroom material

Perfect for: Artists · Merch stores · Classroom projects · Aviation fans

Pack E — Blender Artist Pack (OBJ + STEP + 3MF + GLB + GLTF)

Get Convair Model 61 CJ805 powered — Engineering CAD Pack Here for $12

Includes:

OBJ + GLB file exported from CAD
Ultra-smooth wind-tunnel-grade geometry
STEP file included for those who want to re-export their own mesh

Ready to import into:

Blender
Cinema 4D
Maya
ZBrush
3MF file for layout reference included

Note: Untextured, raw CAD mesh. Perfect for sculpting, kitbashing, rendering, or custom livery painting.

Perfect for: Blender users · Render artists · Hard-surface kitbashers

Ultimate Pack

Includes EVERYTHING in Packs A–E

STL + 3MF 3D Print model
DXF Cross Section Laser Cut RC
STEP 214 + IGES + CGR Engineering model
DXF + PDF + DWG Merch Poster
OBJ + STEP + 3MF + GLB + GLTF Render Artist

What You Can Do With These Packs

Depending on the pack you choose, you can:

3D print the aircraft
Build RC laser-cut models
Perform CAD or CFD analysis
Render it in Blender
Create posters, stickers, and merch
Study the engineering form

This product line is divided into clear “factory-floor” production tiers for different users: 3D printers, CAD engineers, RC builders, artists, and hobbyists.