Sunday, February 6

Build review Pt.I: Bronco OV-10A in 48th scale from ICM Models

ICM's new OV-10A Bronco in 48th scale has been out for a while. Long enough for Andy King to get his claws well into the build of his own kit. Already at the exterior painting & weathering stage, he has paused to point out the finer parts of his build process today in Pt: I of his story ...

Build review Pt. I: Bronco OV-10A
From ICM Models
Kit Number: #48300
1:48th scale
Price:$45 USD from Hobbylink Japan
The Subject: OV-10А Bronco, US Attack Aircraft
The idea of the OV-10 was originally a collaboration between two US Marine Corps officers in the early 1960s who lived near each other at NAWS (Naval Air Weapons Station) China Lake. Their concept was of a rugged, simple close air support aircraft integrated with forward ground operations that were able to take off and land on roads, have a slow to medium speed and be able to loiter in the target areas longer than a jet-engined aircraft.
W.H. Beckett and Colonel K.P. Rice (who were the two people who came up with the concept) developed the basic platform then built a fibreglass prototype in a garage, the efforts of which generated support for the aircraft concept, after which Rice retired from the US Marine Corps and joined the North American Aviation Company to further sell the aircraft.
In 1963 a 'tri-service' specification was issued for the Light Armoured Reconnaissance Aircraft (LARA), approved by the US Navy, Air Force and Army and based on the need for a new type of 'jungle fighting' versatile light attack and observation aircraft. The aircraft already in this role such as the O-1A Bird Dog and Cessna O-2 Skymaster were considered obsolete as they were too slow and had too small a load capacity.
The specification called for a twin-engined, two-man aircraft that could carry at least 2,400 lbs (1,100kg) of cargo, six paratroopers or stretchers and be stressed for +8 and -3g. It also had to be able to operate from an aircraft carrier, fly at least 350mph (560kph), take off in 800 ft (240m) and convert to an amphibian. Various weapons had to be carried including four 7.62mm machine guns, a gun pod with an M197 20mm electric cannon and Sidewinder AIM-9 missiles.
Eleven proposals were submitted with the North American Aviation/Rockwell NA-300 design being selected in August 1964 with test flying commencing in July 1965 as the YOV-10 Bronco. The OV-10 eventually entered service in October 1969 with the US Marine Corps and was also used by the US Air Force and Navy. The aircraft saw combat during the Vietnam war and first Gulf war with the US military eventually retiring the type during the 1990's although in 2015 two OV-10G's were sent to Iraq for light attack duties under the 'Combat Dragon II' program and completed 120 missions.
The aircraft was also used by other countries such as Germany (who used it as a target tug), Colombia, Indonesia, Morocco, The Philippines, Thailand and Venezuela. Other users included NASA, the US Department of State Air Wing, the Bureau of Land Management (as fire-fighting aircraft) and the Californian Department of Forestry and Fire Protection. A civilian contractor, Blue Air Training, acquired seven OV-10D's and G's in 2020 to use in Joint Terminal Attack Controller training and there is also a group restoring seven OV-10D's at Chino airport, California.
The Kit: Bronco OV-1A in 48th scale from ICM Models
When ICM announced a new-tool 1/48 OV-10A there were a lot of happy modellers as previously, the only other 1/48 kit was the VERY old Testors kit that dated from the early 1970's and which was originally tooled by Hawk in 1966. 
The kit needed a lot of work to bring it up to standard, a task made somewhat easier with the Paragon resin correction set however both the Testors kit and Paragon set have been out of production for many years and when they do appear on auction sites they command very high prices. However, that has now changed with this all-new tooling kit and upon opening the box the quality of moulding is the first thing that stands out. 

It features a combination of recessed panel lines and very nicely done rivets and looking at the parts the detailing is pretty good.
Some details such as the vortex generators shown here below are a bit chunky
The plastic is the typical soft type that ICM uses and it can be difficult to work with especially when sanding joints as it is very easy to put in some deep scratches that are difficult to remove (been there done that).
Construction underway!
Anyway, not being able to resist it any longer, I made a start on the cockpit and the basics are there but it lacks the various throttle and flap levers plus looking at reference pictures of an OV-10A cockpit there is a lot of electrical wiring looms that need to be added too. 
The levers were made from strips of plastic sheet while fine copper wire was used for the cabling. It is worth noting that there are two optional rear instrument panels supplied in the kit depending on which colour scheme is chosen.
At the time of construction, there were no etched sets available so the seat belts were added using thin strips of masking tape with fine wire wrapped around a thin strip of brass for the buckles. Various buttons such as the 'coolie hat' and triggers were added to the control columns using heat-stretched sprue and scrap plastic sheet and if you look closely in the rear cockpit I put in the 'relief tube' for the back-seater.
 Both ejection seats had the yellow and black pull handles made from copper wire added. The piece for the nose gear door retraction struts (part E53) was left off until the fuselage was built as it was very easy to damage it during the handling of the model. The rudder pedals are very thick and ideally replaced with etched parts however you can't really see them in the model so I left them as is.
The cockpit was sprayed black initially followed by a coat of Tamiya XF-20 medium grey with other details painted with various Vallejo acrylics. I used the kit decals for the instrument panels and from a distance, they look OK but if I were to build this model again I would look for after-market alternatives.
Before closing up the fuselage I added lead weight to the insides of the side consoles, the rear of the front instrument panel and the rear cockpit firewall as I had a feeling the model would be a tail-sitter. I know it has been stated there is no need for any weight and it's not mentioned in the instructions but I didn't want to take that chance. Another point to raise here is that you need to sand down the edges of the rear firewall slightly as it pushes the fuselage sides out and makes the upper wing joint a less than stellar fit. That's further on in the build but it's worth mentioning at this point rather than later as I'm writing this after the model was built.
With the fuselage together the first casualty was the nose Pitot tube as I managed to bend it so this was cut off and a brass replacement made by Master-Models was ordered.
The fit of the lower fuselage (part A12) to the upper fuselage was OK but did need some filling so for this I used AK Interactive acrylic putty as I was able to clean it up using IPA (Isopropyl Alcohol) as this avoided destroying the surface detail. The two gun pods needed some trimming to get to fit properly and these also required some filling, the guns were left out and will be added after painting.
The instructions show that you need to drill holes in the bottom of the gun pods but after test-fitting the ordnance later on in the build I found the holes were not necessary. 

The nose wheel was glued together (step 37) and after letting it set I had an awkward job of cleaning up the seam so next time around I'll be looking at resin replacements as the tread pattern on the main gear wheels is almost non-existent.
The assembly of the wings is straightforward although the instructions show to drill out holes for weapons pylons in parts C5 and C8. I did this but found out later on that it depends which version you are building as the ordnance table in the instructions show it to be for version 1, the holes were then filled as I was doing version 2.

The fit of the flaps was the worst part and I had to add plastic sheet to some of the outer edges to close up the gaps, the plastic sheet was then sanded to the profile of the flaps.
The gaps on the flap edges were pretty big in places.
On the other hand, the fit of the upper wing was pretty good with just a small amount of acrylic putty used to fill the gaps.
As mentioned above, the only poor fit encountered was the join between the upper wing and fuselage.

As mentioned above, the only poor fit encountered was the join between the upper wing and fuselage.
This can be cured by sanding the edges of the rear cockpit firewall. The tail booms and undercarriage bays were assembled next and the instructions are vague where part E9 attaches to on the main gear doors so the following photos show you.
With the model at this stage, the undercarriage was assembled but without the booms glued into place, all the assemblies were taped together to see if the model would be a tail-sitter even with the weight put in so far. The way the main gear legs fit made this difficult as they kept collapsing but I figured I was going to need more weight so lead was glued into the inside of the engine cowlings using epoxy resin, the insides of the spinners and even the inside of the centreline fuel tank. Happy that it was going to sit on the undercarriage properly, the tail booms were glued into place along with the horizontal stabiliser and the model was left to set.
The instructions show optional holes drilled into the sides of the booms for 'U' shaped aerials however I wasn't sure if these were fitted to the particular aircraft I was modelling and left them off.

The poorest feature of the kit are the engine exhausts as they have the two plates moulded into each half and they are way over scale. The moulded plates were cut out; the exhaust halves glued together then new plates cut from plastic sheet were put into place. When the new plates had set they were lightly sanded until they were flush with the exhaust opening.
Lengths of heat-stretched sprue were added to the outside of the exhausts to represent the weld beads. This is just simple scratch work but it improves the look of the model no end.

The propellers were glued together but remember that they are handed and it's a very good idea to do them one at a time. I didn't then have to spend an hour looking at photographs to figure out which way they went. Doh....
With the model more or less built I added the canopy but before I glued the parts into place I decided to use the masking templates that are printed on the instructions. To do this I made a couple of photocopies of the templates then using a new cutting mat I bought especially for the job (which also came with a craft knife and spare blade for the grand total of £2.50 UK), a strip of masking tape was stuck onto the mat then the templates were taped over it.
I used a straight edge for most of the templates but some were curved and I had to cut them free-hand, however despite being mildly sceptical as to whether it would work the masks fitted the canopy parts quite well with only some minor trimming required.
The canopy parts were almost a perfect fit too with any gaps filled with PVA glue. With the canopy in place the build was finished so I'll give the model a wipe over with IPA to get rid of any grease and dust prior to painting.

And that is part I of the build complete!
That was a very enjoyable build as the fit of parts was mostly very good and the improvements I made were just enough to not get bogged down and risk it being a shelf queen. The only nit-pick with ICM kits is the soft plastic they use as it makes the clean-up of joints tricky so you should only use fine grades of wet-and-dry paper and some of the smaller parts can be difficult to remove from the sprues without breaking them (like the under-fuselage aerial part E51). The plus side to the soft plastic is that it makes it easier to cut clear parts from the sprue without them splintering.
The other issue is with load-bearing parts such as the undercarriage as with the weight I have put in, it makes me wonder if the gear legs can take it. A solution to this is to drill out the gear legs before assembling them and insert brass rods to strengthen them or use metal after-market items.
I was hoping to keep the main gear legs removable to help with painting later on but trying to figure out how much weight was needed meant I had to glue them in place after all so that's going to make painting interesting.
As with any model, there are some simplifications (such as the cockpit), some areas need tweaking such as the flaps but the basics are there and it doesn't take away the fact that this is a very good kit of a type that has been badly neglected in 1/48. Unlike some other manufacturers, ICM includes weapons and with the number of users of the aircraft you are not just restricted to military schemes either.
The history of the aircraft is via the Big Book of Wiki.

Andy King

If you want to know more about this kit check out the ICM Models Website for their distributors worldwide. 

We found this kit for $45 USD from Hobbylink Japan
You can see more of Andy's work at his web page: Andy King's Model Blog