Sparrowhawk (oz3885)

 

Sparrowhawk (oz3885) by DM Collin 1971 - plan thumbnail

About this Plan

Miles M5 Sparrowhawk. Free flight scale power model.

Quote: "A 1-1/4 in equals 1 ft free flight scale model for .5 to .8 cc engines. Miles M5 Sparrowhawk, by DM Collin.

THE GENERAL PROPORTIONS of the Sparrowhawk immediately struck the designer as nearly perfect for a free-flight scale model, when he discovered a three-view drawing in 'The Book of Miles Aircraft', a Harborough publication, no longer available and much treasured by collectors.

The first model built utilised a DC Dart .5 cc diesel, and weighed 14-1/2 oz. In this form it was under-powered and would only just maintain height - although no doubt a lightweight version with a powerful .5 cc engine would be quite satisfactory. However, the resulting flight would be unrealistically slow, and thus a .75 to 1 cc engine is advised.

Originally, the model featured pendulum-operated rudder, but later experiments proved that stability was increased by using a fixed fin and trim tab. To check this, an AM.10 diesel was substituted for the Mills .75 cc, and it was found that providing the model was trimmed to glide straight (or with just a gentle turn), it would fly successfully in quite a strong wind. Even with the model trimmed to stall heavily on the glide there was no tendency to spin-in.

It would appear that pendulum control is fine on a relatively slow flyer, such as the BA Swallow, but on faster models any sudden change in direction due to air turbulence etc causes the pendulum to swing outwards under centrifugal force and tighten up the turn into a spiral dive. This caused quite a few inexplicable random crashes while the pendulum was in use.

The only known deviation from true scale is that the dihedral does not start immediately outboard of the wing fillets.

The Sparrowhawk has extensive sheet areas, so choose soft or medium balsa to keep the weight down. Use PVA adhesive for joints involving hard-wood or ply.

Cut out the fuselage sides and cement on the 1/8 in square edging strips. Build up the wing tongue box and glue between F3 and F4. Stand the assembly upright on a flat surface and carefully check for squareness. When this is quite dry, cement the sides to F3 and F4 but do not put any cement on the joint where the wing tongue box goes through the fuselage sides until after the tail end of the fuselage has been pulled together. This is essential as otherwise the fuselage will not be able to assume the correct curvature between F3 and F4.

When cementing the tail end together, and when inserting the other formers, carefully check that the fuselage remains symmetrical and untwisted. The rest of the fuselage is straight-forward. The curved top decking is easy if you use soft, straight grained sheet wetted on the outside and doped on the inside. Engine bearers are glued into F2 and F3 and before pulling-in the front part of the fuselage sides around F1. Check that the engine can be installed at this stage of the construction and leave off the bottom part of the engine cowling until the engine is finally fitted..."

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Sparrowhawk (oz3885) by DM Collin 1971 - model pic

Datafile:

ScaleType:
  • Miles_Sparrowhawk | help
    see Wikipedia | search Outerzone
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    ScaleType: This (oz3885) is a scale plan. Where possible we link scale plans to Wikipedia, using a text string called ScaleType.

    If we got this right, you now have a couple of direct links (above) to 1. see the Wikipedia page, and 2. search Oz for more plans of this type. If we didn't, then see below.


    Notes:
    ScaleType is formed from the last part of the Wikipedia page address, which here is https://en.wikipedia.org/wiki/Miles_Sparrowhawk
    Wikipedia page addresses may well change over time.
    For more obscure types, there currently will be no Wiki page found. We tag these cases as ScaleType = NotFound. These will change over time.
    Corrections? Use the correction form to tell us the new/better ScaleType link we should be using. Thanks.

Sparrowhawk (oz3885) by DM Collin 1971 - pic 003.jpg
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Sparrowhawk (oz3885) by DM Collin 1971 - pic 004.jpg
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Scaling

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