ARFA Senator (oz11917)

About this Plan

ARFA Senator. Free flight rubber sport model. Wingspan 16 in, wing area 35 sq in.

The original 32 inch Keil Kraft Senator (oz472) dates back to 1950. This here is a later half size version.

Note this plan is a free download from the aeromodeller.com site at http://aero-modeller.com/bonus-coverage-from-issue-1-919/ where there is also a link to a further article detailing a pop-up dethermaliser to fit this model.

Update 09/11/2021: Added article, thanks to RFJ.

Quote: "ARFA Senator (Another Really Fine Aeroplane). The Classic British Vintage Design from Keil Kraft takes a run at small-field compatibility.

The Senator (oz472) was designed by Albert Hatfull and kitted by KeilKraft Kits in 1950 and was intended for builders that were progressing from beginner level aeromodels into a stick and tissue model of more advanced stature. The overall structure of the Senator was robust and the wood size and construction was straightforward and simple. Ample wing area with tip dihedral and a large tail plane made a model that was extremely stable with consistent flight characteristics.

The Senator remained in production by KK for nearly fifty years and has become a favorite for Vintage Rubber enthusiasts who have viewed The Senator as the cabin freewheeler of choice when it comes to competitions.

The ARFA Senator was conceived out of my desire to fly classic rubber designs from my small local flying field, The Grassy Knoll, in Encino, California. All of the classics were too large and high performing for this site. My attempts to cut back the fabulous flight characteristics of these Vintage beauties resulted in uninspiring, low altitude flights. Half-sized versions seemed like the perfect solution and so my quest was at hand.

This British classic seemed like the perfect subject for the new AeroModeller. The Senator met all the criteria for a good half-size classic candidate: 16 in span, potential 12-16 gramme finished weight, character, fair wing area combined with good sized tail area, etc. AND it would fit on a full-sized A3 spread in AM.

Building The ARFA Senator: As would be expected, the construction is exactly like the full-size version only the wood is; you got it, half the size. This puts construction handling on the same level as Bostonian and Peanut scale, so all in all builders like me, that are dexterity-challenged, should not have too much difficulty wielding the lumber. The trick to building any successful half-size subject is careful wood selection. Building light and strong is the key to keeping wing loading low enough to make the bird perform.

Preparation: I like to control the balsa I buy and where it goes in my models. I strip my own and select for specific parts on each model. I picked out some nice 7 lb/cu ft A-grain 1/16 sheet for leading edge stock and fuselage stock, a great sheet of 5 1b C-grain 1/32 for ribs, rudder and sheet fuselage parts, a nice sheet of 10 lb A-grain 1/20 for wing and stab spars and a little bit of 7 lb 1/8 sheet for nose block parts from my scrap bin. I made copies from the plan for templates and made strips of 1/16 sq, 1/20 sq and 1/20 x 1/32 and set them aside.

Cut and sand template parts to shape then move on to make wing and tail tips. If you are building your model with sheet wing and stab tips, you won't need this next paragraph. But, I suggest you read it, just in case you feel like experimenting with moulded basswood instead.

Templates for the wing and tail tips can be made from cardboard or thin plywood. Cut templates to the inside perimeter of the tip outline and make sure they are smoothly shaped and set them aside. For the Senator tailplane and wing, I select basswood strips from 1/32 sq and 1/32 x 1/16 stock and cut lengths about 1 inch longer than needed..."

Supplementary file notes

Article.

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