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1/72 - Cessna 180/185 & U-17A/B Skywagon by Kovozávody Prostějov (KP) - released - Red Roo Models Cessna 185 correction set


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The (under scaled) KP Kit: 

 

52282594012_a907176885_k.jpgUntitled by Harry Follas, on Flickr

 

52283575176_a8bd09c065_k.jpgUntitled by Harry Follas, on Flickr

 

Lars Opland's Khee Kha Cessna 185 bits are about correct for scale 

 

52283585498_ecacc2fe28_k.jpgUntitled by Harry Follas, on Flickr

 

I've laid a vac model over the plans to demonstrate...not the easiest to demonstrate but you get the idea that its scaled pretty much correctly  

52283575271_398905d280_k.jpgUntitled by Harry Follas, on Flickr

 

This is a shame, I was hoping to be able to cross-kit components from these models, alas its not to be. I'm now thinking of onselling the KP models I have as they look small next to the Khee Kha C180/185s  

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6 hours ago, Trenton guy said:

How do we know the plan is scaled correctly? It’s provenance is not mentioned.

While I have no doubt that KP botched something, would also like to know provenance of the plans , way too often kits are trashed based on innacurate drawings.

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8 hours ago, Trenton guy said:

How do we know the plan is scaled correctly? It’s provenance is not mentioned.

Because I scaled the plan drawings (individually) correctly to the actual aircraft :) ! Also physically measured the KP model dimensions, scaled it and it is too small!

Edited by follasha
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Ok The plans are really immaterial, I merely used them to demonstrate the size difference…the actual important aspect here is that the Khee  Kha kit is bang on for 72nd scale. And the KP model is not. 
 

they are best 3 view drawings I could find on the net… I could have used Lars but I needed an independent source, I checked both fuselage length and span ratios before I scaled them so they are dimensionally correct

Edited by follasha
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6 hours ago, follasha said:

Ok The plans are really immaterial, I merely used them to demonstrate the size difference…the actual important aspect here is that the Khee  Kha kit is bang on for 72nd scale. And the KP model is not. 
 

they are best 3 view drawings I could find on the net… I could have used Lars but I needed an independent source, I checked both fuselage length and span ratios before I scaled them so they are dimensionally correct

I don´t like resin kits, but I am interested to build an injection molded Cessna 180.  Any advice? 

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I don't trust any 3-views I find on the web that are not identified as to source. I have an official Cessna 3-view, with dimensions, which I have scaled as accurately as I can to 1/72 using Photoshop. Perhaps it will help determine whether or not the KP kit is actually undersized. I do not yet have an example of the kit to compare to the drawing, so I will leave that up to the rest of you Cessnologists. 

 

180 1959 3v 1-72

 

Edited by Space Ranger
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Hahaha…ok, I used photoshop to scale the drawings I showed here, HOWEVER, it doesn’t need drawings though to scale out actual physical dimensions…I have built 36 of Lars kits and have occasionally substituted Airfix Birdog wings with his models (which also scale out properly) and have substituted VFR Models Cessna 206 wings with Lars 185 wings…all 3 of these kits scale correctly, however the KP model does not 

 

I’ll leave it to you though to make your own determinations 😉

Edited by follasha
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Some of us just want to build a Cessna and aren't bothered by a minor length issue even if there is one. We just want a more or less modern tooling that looks like a Cessna. Im of the mindset that if it looks like a 🦆. Quacks like a 🦆… then its a 🦆. Same rules apply to a model, if it looks like the subject and sits like the subject, then its right to me. 

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I don't think the KP kit is "under scale" - meaning that all the parts are scaled constantly to an inferior scale. To me, the KP Cessna 180/185 kit is just a badly manufactured kit, based probably in the first 3-view drawings found by their "research department" (that meaning probably plans from an old Letectvi + Kosmonautika magazine or another similar source, not caring to measure the main dimensions of the print). We shouldn't take the plans, even the ones originated from Cessna, as God spell - but the main dimensions, published in several sources, should be obeyed! 

 

In this case, the wing span measures 36', which translates to 1/72 (and to my metric system) as 152.4mm. The kit is 147mm, so we're talking about an error of 3.5%. Not too much? Think about a Spitfire or Bf 109 kit with an error of the same magnitude. Fortunately all the difference is concentrated in the outer panels, so you "only" need to fabricate new ailerons and wing tips. Here are the main parts over a 3-view of Cessna origin:

 

KP Cessna 180 1

 

If in the case of the span KP can blame the plans but (and this proves that the kit is made with lousy quality control) how to explain this??? I doubt of the existence of any plan that shows the wing centre section as something different from straight. Once again this is correctable, but we're talking of a kit made in 2022, not "70's old KP" stuff.

 

KP Cessna 180 5

 

Another proof of the lack of care put in this kit is in the next photo. You don't need to measure the alternative wing tips to be sure that they are not symmetric (and I have "old KP" kits with sharper details).

 

KP Cessna 180 4

 

This is not an deep review, but I think that most of the problems in the fuselage are at the back - lacking a pair of mm and with a too low profile (not only from the plans but by looking at photos). But here I may be wrong, and need to take more time measuring and comparing the cabin zone.
 

KP Cessna 180 2

 

In short, the kit is deceptive - even more if we thing when it was first talked about. It is correctable with some work, but we shouldn't have that work in the first place. I recently acquired two other KP kits and they are ok, both in dimensions or detail (talking here of the DH9a and the Sopwith Dolphin). The difference? They were not designed by KP, being licenced molds from others. Latest kits originated by them were a deception to me. 

Carlos

Edited by CarLos
grammar
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That’s great CarLos, can you also check the chord of the vertical stab and it’s height, I believe that is also too small 😉 I suspect there is a similar problem with the horizontal stab…I can’t check the dimensions anymore as I have sold all my kits to aircraft owners  belonging to the New Zealand Cessna180/185 FB page 🤪

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10 hours ago, Ed Russell said:

If you mean you measured an actual aircraft then your conclusion is quite correct.

Heck no! If I did that with a tape measure my measurements would be “all over the place” 🤪

Edited by follasha
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3 hours ago, CarLos said:

In short, the kit is deceptive - even more if we thing when it was first talked about. It is correctable with some work, but we shouldn't have that work in the first place. I recently acquired two other KP kits and they are ok, both in dimensions or detail (talking here of the DH9a and the Sopwith Dolphin). The difference? They were not designed by KP, being licenced molds from others. Latest kits originated by them were a deception to me. 

Carlos

Exactly why I wrote in the KP DH.9A thread that it was such a pleasant surprise for me. Expected something Cessnalike as above and got quite decent kit instead. Thank you for stating the reason, Carlos, I am sure you are right. Nice models from licensed molds made by someone else (CMR), though still marred by lousy researched decals (DH.9A), and much too often sh**ty design of their own molds.

Edited by Patrik
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Measuring a real aircraft’s dimensions isn’t an easy thing to accomplish without some state of the art tech.
Running a tape measure across the wings or length wise isn’t going to give good results. Find the datum line, make sure everything is level, then what ever means to establish the end points are perpendicular etc.
Control surfaces, panels etc. are pretty easy. Although when measuring total span and length, factor in ambient temperature (expansion/contraction). 

I spent a whole day in McMinnville measuring and photographing their B-17G, shortly before it was sold to the Collings Foundation. The volunteers were very accommodating and let me crawl over it at will. Oddly enough after I wrapped up, the volunteers told me that someone from Revell Germany had done the same thing only a few months before. To say I was disappointed when the Revell AG 1/72 B-17G was released is an understatement. He obviously never saw the tops of the ailerons and a number of other things. Oh well, I was just there trying to determine the dimensions and positioning of certain vents and panels, lights etc. Years later, I now have access to the blueprints, where I can check actual measurements used to build the thing, right down to skin thickness, rivet sizes etc. I wouldn’t spend that amount of time on anything other than my passion. BTW Airfix is much more accurate, with the exception of the panel gouges and a few other easily corrected boo boos and omissions.

 

Back to Cessna’s, I’ve painted a few 180/185’s etc. in 1/1, but the only measuring I did was to make sure my graphics were equally positioned. What bothers me most about the models of Cessna’s is the corrugated control surfaces. They aren’t a regular undulating curve like a Ju-52 or Ford Tri-Motor, the “corrogations” are triangular in cross section and spaced about 3” apart and about 1/4” proud of the surface. The trailing edge is very thin with a diamond shaped opening at the ends of the corrgations. If these were done anything close to scale, that would be a big deal for me. The treatment of those on most Cessna kits is very heavy handed, KP no exception. For most, not a deal breaker, but when you spend hours stripping, acid washing, alodining, priming and spraying those surfaces, it’s hard to look the other way. I’ll pick a few KP up to replicate my paintwork, and make corrections as necessary. It’s better than a kick in &$$ with a frozen mukluk.

 

Cheers

Jeff

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2 hours ago, follasha said:

Heck no! If I did that with a tape measure my measurements would be “all over the place”

It's not that hard to do the basic measurements - a couple of plumb bobs, a good tape measure and a large T-square. I have done it a few times - Nomad, Airacobra, Beaufort (bits).

Here are some quoted wingspan measurements.

AOPA 36ft

Wikipedia 35 ft 10in

Global Air 35ft 9in

Cessna Flyer Association 36 ft 2in

Aerocorner 35ft 11in

Pilot Mall 36ft

RAAF Museum 36ft 2in

If they are all accurate 😄 Cessna 180 wingspans may vary by 5 inches! Say 2mm in 1/72.

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I should point out that the drawing I posted came from Cessna, so the dimensions on it should be considered “official.” Also, it is of the “classic” 1959 model, so does not depict subsequent changes introduced on the assembly line.

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The 180 range had a mod to the engine mounts/cowls from the 180C onwards (about 1960)  I suspect there was a lengthening of the mount as well ?? Lars data suggests ad much as 3” difference 

Edited by follasha
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5 hours ago, follasha said:

I can’t check the dimensions anymore as I have sold all my kits to aircraft owners  belonging to the New Zealand Cessna180/185 FB page 🤪

That'll teach me for being too sick to check the forum and FB!!

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I would not care about 5 mm difference honestly. At least we have a plastic Cessna that seems mostly accurate proportionately. But! I feel very bad seeing that plastic quality... What I observe with AZ/KP molds - they are deteriorating over time. Each new model is crappy quality wise. Molding defects, hugely thick transparencies, poor fit, soft details, etc. Quality is horrible. 

And what is the worst - these guys occupy the market and make certain types less appealing to other manufacturers. For example, if AZ issues MB.339/326 series - anybody else considering this aircraft would probably sell 50% less.

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