More Frog Rubber Model Plans

Delta 16

I was very pleased when Peter Williams kindly sent me a copy of this rare plan, which never appeared in his catalogue. I know he spent several years looking for a copy. The model is 17 inch span, so not sure where the Delta 16 name came from. It dates from 1955, and should be an interesting challenge to get it to fly well. I would love to hear about your efforts, should you decide to give it a go, and please send photos of your finished models for inclusion on the site.

The plan shows virtually everything, but you will have to draw up most of the ribs yourself. The shape of the root rib is given, and you can measure the height of the others from the front view, so this should be enough to work with. The sketches indicate that all ribs were flat-bottomed, with no reflex built-in.

The original plan had quite a lot of marks on it, and some dark areas, so I have spent some time cleaning it up. It will print onto 8 pages of A4 or similar sized paper.

Good luck!

Download Delta 16 pdf file here (184 KB)

Download Delta 16 bmp files here (261 KB)

Jim Millisky from Blackwood, New Jersey, USA is the first to send me photos of a finished Delta 16. He says he really enjoyed building the model and it went together nicely. Here are his comments:

"I covered the model with silver tissue and made a canopy for it.The silver tissue proved to be very tricky to cover with, as you can see by some wrinkles in the covering. The finished weight of the model was 18 grams, but test glides have shown it to be nose heavy with a plastic prop, so I will have to make a balsa prop.Properly balanced the model glided very fast, flat and stable. One modification I made was to enlarge the elevons to make it easier to adjust for flight. Hopefully some powered flights will happen in the spring."

Sidney Higgs has also built a Delta 16, and here is his nicely finished example. It has not been flown yet, and I will be more than interested to hear how it goes.


Here is something a little simpler to build and fly than the Delta 16. The Goblin dates from 1950 (so SAM legal), has a span of 24 inches and was sold as a "junior duration" model. The construction could politely be described as "sturdy", but I guess this was to help it survive the rigours of trimming in inexperienced hands. Chris Strachan built one for the SAM35 Gala a few years ago, when Frog models were featured and says it flew surprisingly well. In fact it defeated all the Sprites that were entered in the competition. I think it would make a fine windy weather model.

Many thanks to Chris Strachan for sending me his original example of the plan to scan.

As a bonus, I can now offer a pdf file with parts for the Goblin, including all the wing ribs. This was drawn up by Bill Brown, who was kind enough to send me a copy. Thanks Bill!

Download Goblin pdf file here (291 KB)

Download Goblin bmp files here (325 KB)

Download Goblin parts file here (20 KB)

Barry Fawkes was kind enough to send me this picture of his neatly made Goblin. He says the model is a fine performer, and was putting in flights of around a minute at Old Warden in 2008.

Another nice Goblin, this time built by Dave Rumball of the Peterborough club.


Another nice little two-footer, this time dating from 1949. Like the Goblin, it was sold as a "junior duration" model and is also SAM legal.

Looks like it should be a good flyer, though there is not as much room for piling in the rubber as the Goblin. It should come out rather lighter though.

Should you build one, photos and flying reports would be most welcome.

There are 12 pages to assemble, as the plan is quite large. You may be better just taping together the bits for each part of the model as you build it, rather than trying to get all 12 sheets perfectly lined up. I taped up a test plan to check it and it worked fairly well, though it is hard to avoid vertical drift as you put in the last corner sheets!

Download Sprite pdf file here (222 KB)

Download Sprite bmp files here (327 KB)

Many thanks to Bill Brown for sending this photo of his very smart Sprite, completed May 2005. I will let you know how it goes, as I am bound to see it in action at Old Warden or Peterborough. It only weighs 25 grams without rubber, so I think he had better hang onto it if there are thermals around.

Bryan Stichbury has also built a Sprite, and has made a very nice job of it. and I took this photo at Old Warden while he was giving the model its first test flights.


The 22 inch span Fawn was issued in 1959 as a sports model, and was only produced until 1962, so the chances of finding an original kit would I think be quite slim. No matter, because you can build one now from the plan here. It is a simple design, so even a beginner should have no problem constructing the model, and it certainly looks like it should fly well.

I have drawn up part sheets myself, so would like to know if anyone has any fit problems. The wing ribs do look rather fat, but they are in agreement with the front view of the wing on the plan. Note there is one mistake - rib W6 has been incorrectly labelled as W8. The fact that the wing only has 7 ribs per side is a bit of a giveaway!

One construction point to watch is that the 1/16" sheet parts labelled 1, 2 and 3 are pinned to the building board during construction of the first 3/32" thick fuselage half. However, when building the opposite half on top of the first one, the new 1/16" sheet pieces are packed with scrap 1/16" balsa underneath to bring them up flush to the upper face of the second fuselage half. Quite clever really, and it saved Frog having to put any 3/32" sheet in the kit.

I was delighted to get this picture from Mark Massingill in the USA of his completed Fawn. Mark reported that the parts all fitted well (always a relief!) and the model has flown successfully. The model is covered in yellow domestic tissue, with the lettering and logos printed onto the tissue using an ink jet printer. Very smart it looks too.

The plan is on 8 A4 sized sheets, plus two parts sheets, in both bitmap and pdf format. The plan was scanned at 150 dpi and the small bitmaps are all 1000 pixels wide, so to print out full size you need to set the print width to 6.67 inches (1000/150). I have also provided the plan as one large sheet in bitmap format, in case you feel like tiling it yourself

Download Fawn pdf file here (252 KB)

Download Fawn plan as tiled bmp files (zipped) here (366 KB)

Download Fawn plan as single bmp file (zipped) here (240 KB)


The Minx is an attractive 30 inch span duration model which would be very suitable for beginners I think. The structure is sturdy, and wood sizes big enough for easy handling. It looks like it will be easy to trim, and should fly well. If you build one, please let me know how it goes, and send a picture or two for the site.

Parts sheets are provided for the 1/16 bits, including a full set of ribs for the wing and tailplane. The 1/8 sheet parts (e.g. fin outline) are shown on the plan, and can be taken from there.

Thanks are due to Andrew Darby for scanning the original plan in one piece for me. The pdf of the complete plan is scanned at 300 dpi, whereas the digitally cleaned up tif file is 150 dpi, as are all the other smaller sheets.

Download Minx plan on one sheet as a pdf file here (657 KB)

Download Minx plan on one sheet as a tif file here (343 KB)

Download plan on four A3 sheets as a pdf file here (396 KB)

Download plan on eight A4 sheets as a pdf file here (416 KB)

Download plan on four sheets suitable for printing onto A3 paper (zipped bitmaps) here (383 KB)

Download plan on eight sheets suitable for printing onto A4 paper (zipped bitmaps) here (407 KB)

Download parts on two A4 sheets as a pdf file here 44 KB)

Download parts on two A4 sheets as zipped bmp files here (19 KB)

Thanks to Mel Reid for sending me a picture of his Minx, apparently only the second such model he has built in the last 50 years. Looks great, doesn't it? Initial test flights in less than ideal windy conditions looked promising.


The Mamba is designed along the same lines as the six Frog Senior Series models, so a nice simple build, and gave the modellers of the day a chance to build a semi scale model of a jet fighter without having to go the Jetex route. I built one back in 2001 and it is still flying well today. The duration is rather limited, but it makes a great sport model.

To save you having to mould a canopy, you can use a replica of the canopy Keil Kraft put in their Jetex scale kits. These are available from SAMS models, or Lindsey Smith's "Small Scale Custom Services".

I've done patterns for the fuselage formers, wing ribs and the fin and tailplane parts, but you'll have to get the pattern for the fuselage sides from the side view on the plan. I've tweaked the former shapes shown on the plan to correctly match the plan side view, as there were some discrepancies.

Download Mamba plan on two full size sheets sheet as zipped bitmap files here (265 KB)

Download plan on four A3 sheets as a pdf file here (367 KB)

Download plan on eight A4 sheets as a pdf file here (418 KB)

Download plan on four sheets suitable for printing onto A3 paper (zipped bitmaps) here (294 KB)

Download plan on eight sheets suitable for printing onto A4 paper (zipped bitmaps) here (334 KB)

Download parts on three A4 sheets as a pdf file here (50 KB)

Download parts on three A4 sheets as zipped bmp files here (29 KB)

Witch II

This 36" span design was described by Frog as a high performance rubber model, and this seems to be borne out by this beautifully finished Witch II built by Dave Simons from Sydney, Australia.

Dave says the Witch is a much better performer than he had expected and has a nice floaty glide. He also thinks a button timer is a must! Power is 12 strands (pretensioned) of 1/8 Tan competition rubber and the prop is a 12" version of the Hipperson Senator freewheel prop. It will do a couple of minutes on 500 turns with quite a steep climb.

Thanks are due to Andrew Darby for scanning the original plan in one piece and to Steve from Outerzone for digitally cleaning up the pdf.

Download the Witch II plan on one sheet as a pdf file here (560 KB)

I recommend you either print this plan off using the tiling function in Acrobat reader X, or take it to your local print shop and get them to print it as a single sheet.

General notes on printing the plans

The small T shaped marks you will see on the sheets are spaced 50 mm apart, to help you get the pages the correct size.

The pdf files should print off at exactly full size if you set your printer to A4 paper. Make sure you haven't got "fit to printable area" selected. This should work even if you do not have A4 paper in the printer, as the margins have been left deliberately large.

You will need Acrobat reader to view the pdf files, which is a free download from the Adobe web site

Bitmap files are also provided in case you prefer to work with those.

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