1/2 A Viking

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    Jack Murphy

    Have a few questions about Nos gas. First better introduce myself. Was immersed in free flight in childhood- son of Bert Murphy who flew with the MMAC back in the mid 50s-60s. He spent his childhood building free flight from just after the Wright Bros. got the idea in everybody’s head. Have recently started building F1h towlines. First two models from a Hugh Langevin design. One true to plans and one updated with carbon fiber spar and boom. Wing folded on the original version on the second flight so retrofitted with a new wing and tail boom. Now am nearly finished with 2 new wave Chuck Sotich Lil’ Dips- also with carbon fiber spars and tailbooms. Having a blast though now have to medicate to deal with a sudden allergy to balsa.

    Anyway I have a complete 1/2 A Viking kit. I want to build it and probably a smaller version. Question is- what is the scale reduction for the 2011 One Design? I find it very easy to stack ribs in my drill press- bore a hole and run a carbon fiber spar or two. Would this be legal in the One Design format? Don’t want to start an argument but the new materials make modeling a lot easier and the airframes are far more durable. Ciao! -j


    Here’s the info fo the 2011 One Design Competition taken from: http://www.freeflight.org/competition/one_design.htm

    Carl Goldberg Viking 1/2A (in approved reduced form or in original form from the Goldberg kit). Nostalgia rules. Any Nostalgia legal engine plus TD 049-051 allowed. The reduced form model design will be made available in the late summer of 2008 as a full sized plan. A kit will be available from BMJR. Plans for the full sized Viking are available from NFFS Plans Service for $8.00 (plan number 433)”

    As for construction, I don’t believe the Viking is nostalgia, but am pretty sure the one design event is flown to nos. rules. Taken from: http://www.freeflight.org/competition/NFFS%20Competition%20Rules%202007-2008,%20Release%201.pdf

    “Later Modifications & Approval. Changes in an already approved original gas model design made
    during the Nostalgia timeframe must also be submitted to the design-approval procedure to be eligible for
    competition. The Nostalgia Subcommittee will consider documentation offered to prove that a design flew
    with such modifications in competition during the Nostalgia era. Otherwise, the builder should faithfully
    maintain the dimensions and construction details of the original model, except for minor differences in nose
    moment and thrust line and the following allowed modifications (see Construction Guidelines below)..

    Allowed Modifications. The following changes are allowed in original model plan construction details:
    1. Strengthening and reinforcing materials may be added by using gussets, doublers, larger wood
    sizes, etc.
    2. Additional wing spars at any point, except for turbulator-spars in the forward one-third of the
    upper airfoil, are permissible. One additional spar, flush with the rib surface in the forward upperairfoil
    area, is allowed. Addition of false ribs is permitted, as is strengthening of the wing center
    section with sheet.
    3. Ribs and formers may be added when scaling up and may be reduced in number when scaling
    Restricted Modifications. Construction restrictions include:
    1. No variation in stab location. Changing location from the bottom of the fuselage to the top is
    prohibited, unless it can be proved that the variation was flown in competition during the
    Nostalgia timeframe.
    2. No geodetic or Warren truss-type construction is allowed unless it is shown on original plans;
    3. No addition of sheet to wing and/or stab leading edges is permitted. No substitution of sheet for
    built-up sections on fuselages is allowed, except in high-stress areas like the engine mounting
    area, pylon base and stab mounting area;
    4. Auto-surfaces are prohibited even if shown on the original plans except movement of the rudder
    for Classic Open Towline Glider at the time of towline release is allowed.”

    The wing spar rule definatly has holes regarding materials for spars specific placement, etc. A “spar”, expecially in nos gas, is usually assumed to be flush with the top or bottom. In light of the “Otherwise, the builder should faithfully maintain…” sentence, the addition of carbon tubular spars probably won’t qualify for One-Design.

    Is there anyone who has a different interpretation? This is just mine….

    Jack Murphy

    Hey Brian,

    Thanks for weighing in. I have only very recently began building again after a 42 year hiatus. Have started by building HLGs and tow-line gliders just this year- all from scratch or plans only. Sure is easy to stack ribs on a drill press and run a carbon spar or two completely in lieu of any balsa or spruce. Will build my original Viking kit just as it came and probably one more once it is determined how far it can be scaled down. Still tempting to build a spare wing and stab with the carbon tubes though………..

    Thanks again. -j


    Couple of notes.
    I think the scaled version is at 250 squares. With different spars than original.
    Check the One-design link under competitions on the NFFS site. Vanderbeek is the be-all for the One-Design comps. He can answer for certain any queries.


    Good luck with the project, keep us informed.
    -Brian 😀

    Jack Murphy

    This is how I remember free flighters to be! When I was racing TQ Midgets and mini-sprints my compatriots where just as likely to lay a wrench upside my head! -j


    Jack good luck with the Viking project. I have built both versions of the Viking in the last year. The original at 340 squares and the one design at 286 squares, which is 84% of the original. I was interested in the 1/2a Viking because I think I built one in my youth. Those distant years are a bit dim to me now. Please make allowances.

    I got the full sized plans from the AMA plan service and the reduced plans from John Anderson. Myself and several others from around the country were “proofing” the plans looking for errors and improvements as we built the planes. I will try to attach a picture of the finished model.

    I have my own question about the Vikings (1/2a and FAI). Were they competitive? Lee Campbell has told me he nearly won 1/2a at the Nats back in the seventies. I read some flyers in Texas had good success with it back when it was being kitted. Another well know flyer has told me it was a “dog.” I would be interested what the readers would have to say about the design.


    I do have a picture of the reduced sized Viking, but I don’t have the computer chops to post it. If anyone wants to volunteer for this task I would be more than happy to forward the jpeg to you.

    Jack Murphy

    As to the performance of the Viking- my father Bert Murphy campaigned a lower thrust version (dropped the engine pod down the wing pylon so that it sat on the lower fuselage) with the MMAC in the mid ’60s and had a fair amount of success. He was awful busy then as he was also flying FAI and Wakefield at each meet. He drew a sketch on the box cover of the unbuilt kit I have with the engine mounted all the way down in front of the fuselage. Guess it depends on who and how the model is trimmed as to how much success one may have. Like you, I am intrigued with it from my own memories, also want to build a 1/4A version. So guess we’ll see who finds the trick set-up!

    Regards, -j


    When are the reduced Viking plans going to be available and are they going to be available from NFFS? I’ve always liked the original but thought it was too big…

    Dean McGinnes

    I am interested in knowing how the structure is done on the reduced “One Design” Viking. I have absolutely no interest in internal spars.

    The few succesful Vikings I remember had top and bottom spars. The kits with the die crushed ribs were the only ones that had the internal spars. Some glued the “holes” shut and cut slots around the periphery of the rib. Usually 3 or 4 on top and 2 on the bottom.


    Hey there Dean,
    Last time we met was in the laundry mat in Muncie drying our “dry goods” after an over night rain storm. Back to the Viking; the internal wing spars (apparently loved only by C.Goldberg) have been replaced by 3/32 X 1/8 balsa spars. There are two on top and two on the bottom with 1/16th vertical webbing. Chord wise they divided the wing into thirds. The outer panel spars are tapered; 3/32 X 1/8th to 3/32nd X 1/16th at the tip. If I remember correctly, I didn’t do the taper. After all this was an experimental model.

    Kit Bays
    Stardust wrote:
    Back to the Viking; the internal wing spars (apparently loved only by C.Goldberg)

    Paul Gilliam liked them too. His early Civy Boys used internal spars, at least on the larger versions.

    Dean McGinnes

    OK! External spars with vertical webbing. I can get into that! 🙂


    Here are the two Vikings. Full sized on the right and reduced size on the left.

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