A & DB Models reproduction Frog Heron

Since releasing their first laser cut reproduction kits of the Frog Senior Series range, A and DB Models have been improving the range, and the ones you can buy now have rather more in the box than they used to.

I thought it might be of interest to build an example from the range, especially as Alan and David Briggs kindly offered me a review sample. It had also been a couple of years since I built a Senior Series model, so I thought it was about time I did another one!

I chose the Heron, as you do not see too many of these around, and I gather it is a good flyer.

Here you can see the box and contents before unpacking.

Here are the laser cut parts, stripwood, noseblocks and wheels plus prop bush and wire. The wood in my example was very nice and light, and you can see how clean the cutting is. Note the upper nose block has the goove in the underside to clear the rubber, just as in the original Frog kits. The wheels are injection moulded in two halves, and although heavier than vaform parts would have been, at least they are lighter than one piece solid items.

Here you see the remaining bits and pieces, including pre bent undercrriage wire, a Peck 7" prop, Esaki Japanese tissue (nice to see that in a kit for a change), rubber, window and wheel fairing patterns and a drawing identifying all the parts on the laser cut sheets.

The plan is a very nice reproduction, printed on both sides in the same way as the original

Almost a shame to make pin holes in it!

The fuselage was built first, and went together very quickly. The parts are very simply removed from the sheet, but it is worth spending a bit of time sanding the bumps flush where the joining tags are. Also I would recommend running an emery board along any edge that will be facing the tissue once covered, just to remove the potentially unsightly brown edge. For example, along the bottom edges of the fuselage sides, and the tops and bottoms of the formers and wing ribs.

The kit reproduces the original Frog design accurately, with a fixed nose and just a plastic plug that can be removed to change the rubber. I decided however to give the model a proper removable noseblock, to give a decent sized hole for the rubber, thus allowing stretch winding. This is relatively simple to do. The photo above shows how I have doubled up the front former by adding another piece of 1/16" sheet behind it, then cut a new opening. If you keep the bits you cut out, they can be used for the shape of the plug that will be needed on the back of the removable nose block.

Here is the fuselage completely assembled, but with no carving done yet, and untouched by any sandpaper. I am happy to report there were no fit problems at all. The trickiest bit is probably the planked decking in front of the cockpit, but even this is not too difficult. Just keep checking with the plan to see the length of each piece. The curved shape was cut out after all the strips were in place.

The front undercarriage leg has to be glued to the inside of the lower block before it is glued to the fuselage. The shape on the end of the leg is bent after this (otherwise you could not feed it through the block from the inside).

Here are the wings pinned down to the building board. I would suggest shaping the trailing edges beforehand, as they are quite substantial. All the stripwood supplied with the kit was of good quality, and reasonably light.

All the components are now finished, and sanded and smoothed ready for covering. The fins and tailplane had their edges rounded off (not the tailpane ends), which also removed the brown colouring. Do not forget the wing root gussets, which add strength, and also help to avoid wrinkles in the corners.

The airframe was given two coats of sanding sealer, and the tail surfaces three. These latter were left uncovered, hence the extra coat. Fuselage and wings were covered with the white Esaki supplied, attached by flooding dope thinners through the tissue, thus reactivating the sanding sealer underneath. The sheeted areas around the nose were covered as well, using wet tissue, again attached with thinners.

The tissue was watershrunk, and each wing was held flat while the water dried. Actually, flat is not 100% correct, because I inserted a 1/16" piece of balsa under the trailing edge tip of each wing to add a little washout. It may not need it, but why take chances?

The tissue was then brushed with one coat of non shrink dope, thinned 50/50.

One small modification I made at the rear was to add a small balsa triangle each side above where the tailplane sits. This allows you to cover the fuselage in this area before fitting the tailplane, which can then be slid in and out, and allows for adustment during trimming.

I covered the upper wing tips with a separate piece of tissue to help avoid wrinkles, and guess what? I got a major wrinkle, and I got it both sides. It seems to have occurred due to the step between the rib and the trailing edge. I very nearly decided to live with it, but in the end bit the bullet and cut the offending piece of tissue out of the wing.

It was actually very simple to then apply a small patch to the already doped tissue using Formula 560 canopy glue. After a quick local water shrink, and a coat of dope, the joins are almost invisible, and the whole thing looks much better.

Here is the model ready for its first coat of paint. The notepaper covering of the wing centre section was attached with thin wicking cyano, hence the dark marks around the edges. The undercarriage leg fairings were simply cut from the patterns supplied and wrapped round the wire, using UHU all purpose adhesive (in the yellow tube)

Thanks to the generosity of Dave Causer, I was able to fit a genuine Frog Senior series prop to the model, rather than the (perfectly adequate) Peck prop supplied. The Kit prop can be trimmed down fairly easily to a very similar shape to the Frog one. If you want to enter the model in the Senior Series event at the Peterborough Flying Aces meeting, the prop must be reduced to 6.5 inch diameter in any case, to make it legal.

Here is the completed model, finished in what I hope is a suitably retro colour scheme. The wings and tailplane plus the fuselage side where the stripe would go, and the wheel hubs were first airbrushed using a 50/50 mix of Humbrol Cream and gloss white, thinned with cellulose thinners (dope thinners). When dry, the cream stripe was masked, using notepaper coated with restickable glue stick. This makes in effect large post-it notes, which stick well enough to glossy surfaces to give a very clean edge, with no risk at all of pulling the paint off on removal. The wing and tailplane were masked using the same technique, and Humbrol gloss Maroon sprayed on, not forgetting the fins, and a small sheet of clear deal film, used later for cutting out the wing lettering. The Frog marking was a home made transfer, and the fin stripes were cut from cream painted decal.

Assembly of the main components was done after all the painting was complete. After gluing the fins onto the tailplane, you may (depending on your chosen scheme) need to touch up the paint to hide the exposed taiplane tab The glazing (nice and thin) was attached using canopy glue after painting. The patterns provided give a good starting point, but you will probably need to trim the shapes a bit further before applying.

Final additions were the prop and wheels. I replaced the prop shaft supplied as I felt it was too thin for the bush, and certainly too thin for my Frog prop. The tyres were hand painted, and the wheels slipped onto the wire legs, retained by small sections of plastic tubing and a drop of cyano. Compared to the plan, the wheels are a touch on the large side, but I do not think it detracts from the model's appearance.

To sum up, a very enjoyable build of an attractive and nostalgic model that would be within the capabilities of even a beginner to the hobby. As to how well it flies, you will have to wait and see, but I will certainly let you know when it has.

For more details of the range of Senior Series kits, or to order any of the models, visit the A and DB Model Aircraft web site

Back to Frog Senior Series plans page

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