Alphajet comparative build.

reference drawings : 1/72nd scale aviation modeler december 2009 

left: Heller ejection seats, PJ production replacement Martin Baker Mk.4; right KP ejection seats : for German AJ 

KP fuselage and wings compared to scale drawing : The wings are OK, but the tail appears to be 4 mm too short 

Heller fuselage and wings compared to scale drawing: however,landing lights are not in the wings 

fuselage dry fit : KP seems easier to build; shorter tail on KP not really visible 

ejection seats in both kits can be replaced by resin (mine come from PJ Productions) 

Auxiliary tanks : more complicated construction on Heller; I won't use them anyway on Belgian AJ 

Wings : separation of upper and lower wings different . KP needs some clean up to get a good fit 

Inlets : slightly better on KP , in the middle resin replacement for Heller by Pavla 

Dry fit of the fuselage; Heller parts a little bit warped, but it can help to fit the cockpit. Bottom part of KP is easier to fit than the Heller. I think they need both some weight in the nose. 

Undercarriage construction is similar on both kits; but I think it is better to wait with therese parts, till the end, even after painting. 

The wing slots on the KP kit need widening to fit the tab. Heller fits fine 

Cockpit construction similar, Heller gives more space for the pilot. There is a Pavla resin replacement for the cockpit scalemates.com/kits/..-alpha-jet-e--153228 which costs more than the kit. I will not use it. I think this makes only sense if you want to build a "competition" model with open canopy, which is way beyond my capabilities.
So I will simulate minimal detail in the cockpits, below a closed canopy and with resin ejection seats  

Nose gear : KP parts look like a copy of the HELLER. Neither one ressembles the real one 

The main gear looks too tiny on both kits 

A good fellow measured the gear at the 1 Wing Historical Centre at Beauvechain. Nose and main gear definitely need a replacement 

After two weeks of trial and error to make a replacement gear (in the middle) I decided to keep the kit parts and to modify/ reinforce them with bits of 1 mm and 1,5 mm plastic rod . 

The KP wings have the right shape and engraved panels, which is OK for me. The Heller wing needs corrections with putty. The flap hinges need also a correction. I tried to engrave the Heller wing, but my skills are so bad, I decied to refill it again. I think it will not make a big difference with the special decoration I intend to use.  

Both kits have " empty shelves" behind the ejection seats, although there is a lot of stuff visible there. Luckily there are some well documented builds of the Kinetic 1/48 kit, which give a good view of what it could be. I added bits and pieces with plastic card and rod to simulate the equipment in that area  

 

 

 

Cockpits detailed with bits and pieces, PJ production Martin Baker seats, HUD display of acetate sheet 

The KP cockpit improved 

The Heller cockpit improved 

ready for primer, just a bit of putty needed on the joints 

grey primer AK and some small corrections 

basecoat magenta (almost pink) before yellow 

I used oramask sheet for masking 

masking top 

masking bottom 

masks removed and more masks added. Some corrections needed 

paint disaster. When trying to correct some over and underspray with a brush and AK real color, the paint resolved the underlying coat and when I tried to remove it with Lifecolor cleaner , the paint started chipping . I will now strip off all the paint and restart  

tinkercad design for nose wheel replacement 

tinkercad design for main gear replacement 

tinkercad design for cockpit improvement 

comparison between KP kit parts and resin 3D printed replacement and PJ resin ejection seat 

But the KP main wheels are much better than the Heller/Revell ones 

The nose streaks are very thin and tiny : I will use PE leftovers to make them 

new paint scheme for the Heller kit: Lifecolor Red and Yellow waterbased acrylics. 

new paint sheme for the Heller kit : Revell enamel blue spray 

I found in my collection this model, brush painted +20 years ago, the varnish became yellow. After stripping the paint with oven cleaner, it appeared to be the Fujimi/ Heller kit underneath.  

The Fujimi/Revell kit: old model Paint removed, ejection seats removed, UC removed, and new coat of Tamiya AS-16 light grey , 3D cockpit details added, PE strips on the nose. Will be repainted in the early vietnam type camo 

laser printed decals for the upgrade 

the plane 

the model 

the model 

happy with the 3d replacement U/C 

the bottom, paint error difficult to correct 

back view 

Revell/Heller finished. I got a lot of issues with the old DACO decals, which were rather stiff and did not react well to microsol. Luckily the set I had contained two identical sheets, so corrections were possible . 

Top view 

Bottom view 

front view 

this one is finished too : old Fujimi/Heller kit, paint removed, new ejection seats, new main U/C , repainted and new decals 

Final