1/20 scale Cessna C-172 Skyhawk model by Nichimo

[Nick_Karatzides]

1/20 scale Cessna C-172 Skyhawk model by Nichimo

Few weeks ago I started trying on a Cessna 172 Skyhawk CAD file in order to print it on a 3D replicator and become an actual object under 1/18 scale. It took some time, longer than expected, to shape a realistic looking Cessna with full interior, having always in mind that the later 3D printed parts, should perfectly match and finally become a fine scale model.

If you are interested to have a look on previous scale models scratchbuilt by CAD designing & 3D printing, feel free to click HERE and HERE.







Unfortunately, the project had already gone beyond the expected timetable and the results were not completely satisfying for me. Additionaly, the printing cost calculation proved much higher than I would like / wish. An 1/18 scale Cessna 172 Skyhawk with full interior cabin, measuring approx 46 cm length and 61 cm wingspan, requires much 3D printing material (UV cured acrylic polymer) to get printed and more material means higher cost.

[Nick_Karatzides]

CHAPTER I - Ho, ho, ho! Merry Christmas

It seems I was a real good boy during 2013, so Santa Claus rewarded me by sending an unexpected present. Of course, I am referring to the Nichimo's 1/20 scale Cessna 172 rare kit, which my sunshine had secretly bought and gave to me - among other things - as a Christmas gift.



From one side, I had an ongoing CAD building project that seemed to go wrong and same time I received as Christmas gift same aircraft in about similar size. I was about to accept a tactical concession, reject for the moment the 1/18 scale 3D printed option and move for the 1/20 scale injection molded. Moreover, I believe that the size difference is so small, that would not worth insisting for the CAD design which requires much more work and costs more. Yeap, such coincidental circumstances makes me feel damn lucky modeler.



Despite the fact that Nichimo produced this model about 25 years ago, the kit I have in my hands, looks like brand new. That might means that it was carefully stored all these years or it's a reissue. Nowdays, this kit is quite rare and if finally found, sellers usually ask for unreasonable prices. Googling revealed outrageous examples - an eBay seller is asking for 545 USD plus shipping charge.



The text following is to describe the 1/20 scale Cessna C-172 Skyhawk model building, working on the Nichimo's kit.

[Nick_Karatzides]

CHAPTER II - Meeting the Cessna Skyhawk

The Cessna C-172 Skyhawk is a 4-seat, single engine, tricycle landing gear, high wing fixed wing aircraft made by the Cessna Aircraft Company. First flown in 1955, first production models were delivered in 1957. The airframe has remained almost unchanged since the mid 1960ies, with avionics & engines updates including the Garmin G1000 glass cockpit. The older Skyhawks shipped with a 145 horsepower engine but later planes shipped with up to 180 hp engines. It's also available with a retractable landing gear or floats. Around 43000 Cessna 172s have been built up to date, while it is still in production.



It is the most popular flight training & private aircraft in the World. Today, experienced airline captains who sit behind Airbus A380s or Boeing 787 Dreamliner flight controls, Air Force hi-tec fighter jet pilots and weekend pilots have one common experience - they all flew their first solo on a Cessna C-172. The technical data & general characteristics are:

• Type designation: Cessna C-172 Skyhawk,
• Crew: 1 pilot,
• Capacity: 3 passengers,
• Year of first flight: 1955,
• Country of production: United States,
• Length: 27 ft 2 in (8.28 m),
• Height: 8 ft 11 in (2.72 m),
• Wing span: 36 ft 1 in (11.00 m),
• Wing area: 174 ft² (16.2 m²),
• Airfoil: Modified NACA 2412,
• Aspect ratio: 7.32 / 1,
• Empty weight: 1691 lb (767 kg),
• Gross weight: 2450 lb (1111 kg),
• Fuel capacity: 56 US gallons (212 litres),
• Powerplant: 1 × Lycoming IO-360-L2A four cylinder, horizontally opposed aircraft engine, 160 hp (120 kW),
• Propellers: 2-bladed metal,
• Cruise speed: 122 knots (226 km/h),
• Never exceed speed: 163 knots (302 km/h),
• Stall speed: 47 knots (87 km/h) when power off & flaps down,
• Range: 696 nm (1,289 km) with 45 minute reserve, 55% Power, at 12000 ft,
• Service ceiling: 13500 ft (4100 m),
• Rate of climb: 721 ft/min (3.66 m/s)
• Wing loading: 14.1 lb/ft² (68.6 kg/m²).

[Nick_Karatzides]

CHAPTER III - Starting up 1.0.1

Before start building a new scale model, I always try to study as much as possible the object of construction. If books, technical manuals and detailed walkaround photos are available, that will help a lot the model building process. To know how it works and how exactly it is made on real aircraft, always helps to build the scale model. Since I already had the official 662-page technical & maintenance manual for the Cessna C-172, the 448-page aircraft's spare parts catalog and the 1990 dated T.O GR1T-41D-1 flight manual for the Hellenic Air Force's T-41D Mescalero (Cessna 172's military version) in hands, I thought that it would be the best reference I could get before start building this kit. As always, enthusiasm encourages grandiose plans for scratch work, opened panels, hatches, doors etc.



The model parts are placed into sealed plastic bags. Careful inspection followed to spot any possible defects, cracks, broken parts & imperfections etc. As expected, everything was normal. Before starting the building, I placed the parts side by side and compared them with the diagrams and Nichimo's printed instructions. The model comes with a detailed cabin interior to include a realistic instrument panel. Unfortunatelly, Nichimo designed this model kit, without locator pins for matching the opposed parts, which translates as additional dry fitting work to match & aligning parts correctly before gluing. On the other hand, the aircraft's engine seems to be a real masterpeice and I believe that it could easily stand alone as a complete scale model. Of course lot of scratchbuilding is needed in order to make this Cessna look accurate in scale.



Unable to resist the temptation to cut the sprue parts & play with my new toy, I hurried to glue the fuselage main L & R sides. Yeah, yeah, I know - we are all styrene junkies. After my sweetheart wife inspected the result & confirmed that her Christmas gift made me very happy, she smiled & proudly signaled green light for further building.

[Nick_Karatzides]

CHAPTER IV - Dressing code options

A typical modeller has already decided all the details about the model he is about to build (color, nationality, diorama scene etc.) from the beginning. Those who have attended my previous projects, may recall that this is not my way. I prefer to proceed one small step every time, depending by the up to date results and continue building accordance with the outcome so far and my mood.

What I DO have in front of me is a brand new 1/20 scale kit, asking fully customization with styrene & 3D printed additional details.

What I DO NOT have yet, is a clear working plan & a final objective. I have not decided yet about which production version, which variant, which color setup, which nationality etc. To be honest, there are some alternative plans, but none of them had excite my enthousiasm yet. Some of the (so far) under consideration candidate projects, are the following:

• Cessna 172M Skyhawk s/n 17262486 registered as SX-AMW to Thessaloniki, Greece aeroclub.
  
  This specific aircraft, was used for skydiving purposes during mid-1990ies, by the newly created skyding school of the aeroclub. The interesting point in this candidate project, is that the interior had been configured for skydiving by completely removing the right door, the right pilot's seat, both rear seats and the right flight yoke on control panel.
  
  Special thanks to Mr. Vasilios Katiniotis, an ART-42/72 airline pilot, commercial helicopter pilot & instructor, glider instructor, skydiver and scale modeling enthousiast, for his kind support and providing all the pictures & info I asked for.
  
  
  
  
  
  Also - and this might be most interesting - the aircraft was named as "CAPTAIN ALEXIS BRIDAK" in honor of KIA Captain Alexis Bridak, an F-16 Fighting Falcon pilot and member of the Thessaloniki aeroclub. By the age of 30, Captain Alexis Bridak was admittedly one of the most skilled HAF pilots & a highly decorated flight officer, with thousands of hours flight experience on Mirage F-1CG, F-4E Phantom II and F-16 Fighting Falcon fighters. He was killed on November 26th 1992, during a mid-air collision crash, while performing DACT - Dissimilar Air Combat Tactics maneuvers.
  
  
  
  
  
  
  
  

• Cessna T-41D Mescalero as used by the HAF Academy / 360th Basic Training Squadron "Thales".
  
  The aircraft is a bare-bones Cessna 172, designated by the Air Force as T-41 and officially named "Mescalero". It is used for preliminary flight screening of Air Force pilot candidates before their entry into undergraduate pilot training. The T-41 trainer is equipped with avionics and other equipment consistent with military missions. The "D" version is actually a T-41B for export under the MAP - Military Aid Program with 28V electrical system and simplified equipment, powered by 210 hp Continental IO-360 engine. The HAF Academy acquired the T-41s in 1968 for use in its pilot indoctrination program, which allows cadets to experience in an aerial environment principles learned in other academic courses. Cadets in the program fly approximately 25 hours dual and solo and receive their first HAF flight check.
  
  
  
  
  
  The T-41D Mescalero has some external differences from her Cessna 172 civilian sister. These differences should be taken under consideration, for a realistic result. These slight but visible differences, are the following:
  
  • The Cessna 172 is equiped with a four cylinder engine (Lycoming IO-360-L2A) instead of a six cylinder engine (Continental IO-360-D) on the T-41 Mescalero,
  • The front side of engine cowling on the Cessna 172, is completely different from what used on T-41s. Additionaly, bigger engine on T-41 Mescalero, means slightly more swollen engine cowling than found on the civilian Cessna 172 version.
  • Different engines, means different exhaust pipe shape.
  • The Cessna 172 is equiped with a propeller with the spinner, but the T-41 has a larger hub for the constant speed mechanism that cannot covered by a spinner.
  • The Cessna 172 is equipped with two taxiing headlights, found on lower front side of engine cowling. These lights are absent on the T-41 version which is equipped with one taxiing headlight found on left wing's leading edge.
  • The Cessna 172 is equipped with an air duct, found on lower front side of engine cowling just under the twin taxiing headlights. The T-41 is not equiped with such air duct.
  • The tail fin extends forward & reaches close to the rear window on the Cessna 172. On the other hand, the T-41's tail extension is not so long. Notice: Pre-1968 172s also are equiped with short tail fin extension.
  • The Cessna 172 is equipped with 2 cabin roof windows. These windows are absent on the T-41 military version.
  • The Cessna 172 is equipped with wheel fairings. These caps, should be removed if the plan is to replicate a T-41.
  • The Cessna 172 is equipped with smaller wheels & thinner tyres than the T-41, which is equiped with bigger and more wide ones.
  • The Cessna 172’s wing tips are slightly curved downwards. On most T-41s this feature is absent.
  • The Cessna 172's main control panel is different of the Mil Spec type found into a T-41. No big differences, but quite notable.
  • The flight control yokes are in a Cessna 172 are different comparing to ones found into a T-41 cockpit.
  • The Cessna 172's front & rear seats have headrests & nicely ribbed seatbacks. Headrests are not found on military T-41 version.
  • The Cessna 172 is equipped with a jump seat in the cargo area behind the rear seats. This feature may not be found in every T-41.
  
  
  

• Reims Cessna F172P Skyhawk registered as D-ECJB, flown by Mathias Rust, on May 28th 1987.
  
  This specific aircraft, was used by the 18 years old Mathias Rust, a German amateur pilot with about 50 hours of flying experience, who took off from Uetersen near Hamburg, Germany and following misleading path with intermediate stops, finally landed n Vasilevsky Descent next to Red Square near the Kremlin in the capital of the Soviet Union. His Reims Cessna F172P was modified by removing some of the seats and replacing them with auxiliary fuel tanks. During his attempt, he 've been tracked several times by Soviet air defence & interceptors. Soviet fighters never received permission to shoot him down and several times he was mistaken for a friendly aircraft.
  
  
  
  
  
  After failure to reply to an IFF signal, three SAM divisions tracked him for some time, but failed to obtain permission to launch at him. All air defenses were brought to readiness and two fighters were sent to intercept but permission to engage was denied. Finally, Rust appeared above Moscow's center. He had initially intended to land in the Kremlin, but changed his mind: he reasoned that landing inside, hidden by the Kremlin walls, would have allowed the KGB to simply arrest him and deny the incident. Therefore, he changed his landing spot to Red Square. Heavy pedestrian traffic did not allow him to land there either, so after circling about the square one more time, he was able to land on a bridge by St. Basil's Cathedral. A later inquiry found that trolly wires normally strung over the bridge - which would have incidentally prevented his landing there - had been removed for maintenance that very morning, and were replaced the day after. After taxiing past the cathedral he stopped about 100 meters from the square, where he was greeted by curious passersby and was asked for autographs. A British doctor videotaped Rust circling over Red Square and landing on the bridge. After been arrested two hours later, he claimed that his flight was intended to reduce tension and suspicion between the two Cold War sides. He was sentenced to four years in a general-regime labor camp for hooliganism, disregard of aviation laws and breaching of the Soviet border. He was never transferred to a labor camp and instead served his time at the high security Lefortovo temporary detention facility in Moscow.
  
  In 2008 his D-ECJB aircraft was placed in the Deutsches Technikmuseum in Berlin, Germany.
  
  

I have not decided yet which one of these to build, or if eventually emerged something more interesting. You are all welcome to propose something interesting, so this will become an interesting interactive WIP. For the moment, I 'll sit back, think about it, read some of your feedback proposals and get back to you when I have final decision for the Cessna’s dressing code.

[pickelhaube]

Hey Nick,

Thanks for the history on this plane.

So are you going to build the 1/20 or make it in 1/18th ?

Is the 3-D printer yours or works ?

I kind of like the military version although the kid who landed in Moscow is historical.

[Nick_Karatzides]

So are you going to build the 1/20 or make it in 1/18th ?

I am not a native English speaker, but I think I use the language to a level that people can understand me. OK, I may do some syntax errors sometimes, but I do efforts to improve myself. If you have attended my previous projects, you may recall how I did CAD design, 3D print, assemble & paint. If not, feel free to have a look on my previous projects by clicking HERE and HERE - I'm sure you 'll find it interesting and answer your questions too.

So, as I wrote before, since early November 2013 I was working on an ambitious project, trying to build a Cessna 172 Skyhawk CAD file in order to print it later, in any possible scale, on a 3D replicator. Just because the 1/18 is my favorite scale, the objective was to 3D print the parts under 1/18 and later assemble as ordinary kit in order to become a fine scale model. Unfortunately, the CAD results were not completely satisfying for me & I already spent much more time than expected on this.

My previous 3D projects, required less than $50 to print (although produced in large 1/18 scale), because the first (IS-A Salamandra glider) was produced as a cutaway model and the other (Wallis WA-116 autogyro) had small volumetric dimensions, meaning low requirements on cubic centimeters of printing material. On the other hand, printing the Cessna 172 Skyhawk under 1/18 scale, might increase the cost more than $450, which seems to be much higher than I would like / wish. Bigger parts means bigger printing arreas, which requires much more 3D printing material (UV cured acrylic polymer) and this can be translated as higher cost. Of course, I could also print the Cessna parts by using cheaper 3D printing material (LASER sintered nylon plastic or acrylic based photopolymer), with much less than $150 cost, but the printing detail would not be perfect, since these materials tend to become porous.

Finally, Santa Claus saved me by offering an unexpected Christmas gift when most needed - that was a very welcome coincidence which should not be wasted. An about similar size Cessna was my best excuse to abort (for the moment) the planned 3D printing attempt under 1/18 scale and try a new 1/20 scale injection molded kit instead. I believe that the size differences are so small, that does not worth to take the risk of a scratch building.

...am I clear enough now?

[granch]

Hello,
I'm french speaking and your english is far better than mine, but I can still understand you.
I tried to find some civil airplanes and boats in the 1/18 scale. Just found one balsa kit from www.guillow.com and it's a Cessna 170. Very thin balsa laser cut to make a free flying model with twisted rubber band power. But it could also be a nice model when going on with a complete rebuilt of the cabin. Hope to have the patience to make it once time. Guillow's produce other models and scales of course.
You make a really wonderful work but you seem also to have the time to do it... With my job, children and family life and country house, I can only go on with 10 minutes step a day for any custom in my cellar, mainly just after midnight...

[Nick_Karatzides]

Just found one balsa kit from http://www.guillow.com and it's a Cessna 170. Very thin balsa laser cut to make a free flying model with twisted rubber band power. But it could also be a nice model when going on with a complete rebuilt of the cabin. Hope to have the patience to make it once time. Guillow's produce other models and scales of course.

I know Guillow's models. My personal opinion is that not suitable for "scale" modeling. Maybe for "RC", maybe built by someone else (not me) highly skilled and dedicated. Guillow? No, thanks.

You make a really wonderful work but you seem also to have the time to do it... With my job, children and family life and country house, I can only go on with 10 minutes step a day for any custom in my cellar, mainly just after midnight.

My friend, you are not the only one. I also have a family to take care, I also have a job, I also spend 8 hrs per day to work and be able to pay the bills, I also do not have plenty of time - actually my time window for the hobby is about 2-3 hours every weekend.