review Review: KittyHawk Model 1/32 P-39Q/N "Airacobra"

[Bill Cross]

 As you can see, the late model P-39's were by far the most plentiful, although some of them may have arrived too late to see action.

Thanks ever so much, Tom. I don't plan on buying this kit tomorrow, so many the AM decal folks will bring out a plane or two that def saw combat.

[Hubert Boillot]

Be careful with comparisons between a pic of a kit, and a profile pic of an aircraft, both having potentially barrel distortion because of the camera lens, plus you are not even sure the aircraft pic is not distorted between height and length ...

 

As for the short shots, it may be linked to the metal of the mold, but it is more likely a question of design of the molds with parts, sprues, and "gates" between the sprues and the parts. Having thin "gates" helps separating the parts from the sprues, with minimum cleaning up, but also means the molten plastic will have more difficulties filling the cavities in the mold, all the more so as modern injection machines tend to have short cycles, where the time between starting the plastic injection after mold closure, then cold water to cool down the mold and the plastic - which will stop "flowing" below a certain temperature, then ejecting the sprue, will be a few seconds ...

 

Modern softwares can simulate the molten plastic flow in the cavities (this is called rheology simulations IIRC) but as for everything, there is a balance between time and cost of development, time for modifications, etc. to be found ... Designing kit molds is an art, as you often have more sprues than actual cavities for the parts, and the layout of all the parts in the midst of sprues imposes limitations to where you can position the injection points. This is very different from most injected plastic parts, where the "sprues" are in fact designed and positioned to help optimise the filling of the cavity, and their separation from the part when opening the mold and ejecting the part.

 

Injection pressure is not a function of the mold material, but rather of the mold's area and cavity volume (it therefore increases as a square, or even cube relation to the mold dimensions). "Short run" molds are made of less resistant metals than a "long run" hardened steel mold. Being of softer metals, they will be easier to mill (and therefore cheaper to manufacture overall). But they will require the same injections and closing pressures as a "long run" mold. They will however show far less resistance to these constraints, and will wear out quickly ...

 

In summary, short shots can be avoided by smart designing of the mold, using modern software technology to simulate plastic 'flow', and when they appear regularly, by modifying the injection gates. They can however appear infrequently, and it is then a "simple" issue of QC after injection.

 

Hubert

Edited September 3, 2015 by MostlyRacers

[DougN]

If someone has the time to do a side-by-side and taped together photo comparison of the SH and KH fuselages, it would be greatly appreciated! 

Edited September 3, 2015 by DougN

[DeanKB]

To my untrained, amateur, ageing eye, I must say that it looks like the kit is a tad too short aft?

 

Then again, I'd be utterly staggered if that were the case, as KH would surely not replicate the biggest, most well known error on the existing Special Hobby kit.

 

So I conclude that my ability to judge shapes and sizes is not good - in fact, it's bad. 

 

It just goes to show how difficult it is to judge sizes and shapes when comparing photo's of full sized subjects to model kits.

[LSP_Kevin]

The KH fuselage is in fact quite difficult to measure without first assembling most of the kit, as the entire nose is composed of several separate panels that require the internal structure to be in place. Rather than an overall measurement, a quick and relatively simple comparison of the two kits might involve measuring the distance between the trailing edge of the wing root and the leading edge of the horizontal stabilisers. If my SH kit wasn't so difficult to get to, I'd give it a go. Tom?

 

Kev

[Tom]

OK, I'll take a stab at this, as I have both kits out and on my work table.    I used the aft edge of the fillet that blends the wing to the fuselage as one measurement point and the leading edge of the horizontal stab junction with the fuselage as the other measurement point, then dropped vertical lines using blue tape and measured the horizontal distance between the two tape edges.    Result:   Special Hobby:   1.38"       Kittyhawk:   1.42"     (pretty close)

 

Comments:   1)   this was a quick and dirty measurement.   Might be off by a rch or two.   2)  it only measures a small section of the total fuselage length.    3) it doesn't deal with the most pertinent question:  What did the real aircraft measure?   4) to my eye, the Kittyhawk kit 'looks'  better than the SH kit.   Quite possibly because the Kh kit rear fuselage is slimmer than the SH fuselage and thus the visual effect of the fuselage length is not as apparent.    No science here, just my eye.   What do y'all think?

[LSP_Kevin]

Thanks for taking the trouble, Tom! A rough conversion gives me 35mm (SH) vs 36mm (KH). But of course, proportionality is more important than exact measurements, and it sounds like KH might have the edge here.

 

Kev

[LSP_Ron]

It does appear a little off in some areas but I'd suggest binning that side view of Brooklyn bum,  good reference but nothing to be relied on to compare accuracy in any axis. You are kind of doing this.

 

 

They are taken at different angles and don't account for lens distortion nor perspective from distance from subject/size of subject.  One is real, one isn't.

 

I will say the rudder does not seem to be round enough on the kit though, but an easy fix.

[Alburymodeler]

The starting point should be the fuselage stations, I recall they have been published sometime recently about these parts. Zero inches is possibly behind the spinner, and it should be easy to compare the incremental inches to points on the kit, back to the rudder post and then beyond.  Comparison with photos is fraught with all sorts of fraught things, but the trailing edge of the wing does appear to be too low (a la Spitfire) in relation to the lower fuselage line.

But I think this is as good as it will get as far as the P-39 goes. We have to live with this for better or worse.

[thierry laurent]

This is also interesting to illustrate another aspect: if this is kit is far more detailed and surely easier to assemble than the SH kit, it is not really more "accurate" and for some specific external points, the European kit is better.

 

I 'll get one but will wait for another boxing of an earlier mark (P-400 or similar).

[Urs]

I think its a pretty good kit - and l'm desperately waiting for my copy having a journey from LuckyModels to my doorstep.

Comparing the kits of the P-39 actually on the market that new one is surely a big leap ahead and I'm sure I'll have much fun to super the cockpit or the inner of one or the other access doors.

 

KittyHawk has a good hand with which a/c type is needed on the market. Now a fantastic P-39, tomorrow a nice Kingfisher we desperately expect. I'm sure some modeler turns their kits into bijoux and having fun with them. I agree a model should represent its real life master as much and as close as possible, but everything within its limit. To compare outlines, panel lines and rivets its needed to have the tooling drawings and plans of the real thing. In my opinion - as an engineer - by myself it makes very little sense to compare angled shots of the real thing with angled model views . Just my 2 cents

Edited September 4, 2015 by Urs

[mozart]

I've no intention of building a P-39 but I'm interested in KH's development since they are clearly looking at the less-than-obvious types. Thanks for your review Kev, very well written in every respect and importantly well balanced and objective. No producer can quibble about that but only use it as constructive criticism for further improvement.

Max

[Guest Clunkmeister]

Urs, bang on! You nailed it perfectly.

 

Other than one or two people here, NOBODY has both kits side by side, and NOBODY has identical profile sideviews of the real a/c, SH, and KH to compare side by side.

 

I think maybe it would be best for all of us to do the absolutely unthinkable here, and that is to actually WAIT to pass judgment until we have actual data in hand, instead of everyone throwing out buckets of wild speculation.

 

To me, who is admittedly a hobby builder, less concerned with every rivet and fitting than absolute perfection down to rivet spacing, depth, etc, this absolutely looks like a P-39 to me, and the lines look right.

To even my untrained eye, the rear fuselage of the SH kit appears fat and out of proportion, but this looks "right".

Yes, the rudder looks a bit straight on the trailing edge, but for the average builder, that fix is 1/2 hour or less with some sheet styrene and a scriber.

 

Kevin gave us a straight unbiased review, pointed out the good and the not so good, and to me the good FAR outweighs the not so good.

I've waited to a good P-39 for years, and I, for one, am super glad this kit is finally here.

I'll build the heck out of these, and I'm sure they'll look just like a P-39. Like was mentioned before, nobody else will kit these, so KH doing them is a blessing.

Let's build!

[andromeda673]

I think what Kitty Hawk is doing is bad ass, and I hope they keep it up...........P51 B/C please!!!!!!! 

[Night Hog]

Amen!!!!!