BuiltWithNOF

MIKE ROACH’S MODEL AIRCRAFT

THE SOPWITH PUP - A MODEL FOR INDOOR FLYING

The Sopwith Pup is not the most famous aircraft of WWI: that honour surely belongs to its older brother the Sopwith Camel, but it is perhaps the most loved biplane after the DH Tiger Moth.  By all accounts it was a well-harmonised aircraft, easy to fly, rugged and reliable.

The model is another from my Depron indoor stable, wingspan 32” weight only 7.5 oz, giving a wing loading of 2.8 oz/sq ft.  A small brushless motor provides the power, driving a 7x7 GWS prop.  Controls are rudder, elevator and throttle.

The construction is standard Depron, with 3mm curved plate wings, functional rigging and basswood struts and undercarriage.

The colour scheme is that of FSL LS Breadner of No. 3 Squadron RNAS in April 1917 and all details including the outline plan were taken from the Windsock Datafile published by Albatros Productions.

November 2008.  The model has flown successfully out of doors and is having its first indoor flight at Calshot Velodrome on Friday 12 December 08.  It does need the dihedral on the starboard wing increasing slightly, but is otherwise OK.

Its flights at Calshot were very successful, after adding a large amount of up aileron on the starboard side.  Some side-thrust is obviously needed...

March 2009.  The Pup then sat on a shelf for a month or two, until I got the urge to get the rigging right.  During this idle time I was making the Canadair CL-415 and thinking about repairing the Catalina and had made a commitment to go to the BIMBO meeting in May 09, taking both these models.  Lying in bed early one morning I had a vision of flying a Sopwith Schneider or a Baby, 30” span, Depron construction.  The simplest thing to do was to make some scale floats and a new fin and rudder and fit them to the Pup.  Two days later the model was complete and, to my mind, very pretty.

As far as anyone knows, none of the thousands of Pups was converted into a floatplane, but if one had have been, this is what it would have looked like, with floats, fin and rudder from a Baby.  I suppose that Sopwith might have tried out longer main floats and done away with the tail float, as he did on the unsuccessful post-war Schneider Racer, but this will have to do for now. The little water rudder is connected by a CF rod to the main rudder and it will be interesting to see whether the model can be persuaded to track across the water in a straight line.  Now that the excessive washout on the port wings has been corrected, I will have to straighten up the aileron on the starboard side.  I hope...

All she needs now is the fin trademark, a beaching trolley and a trestle for the tail!

And she floats, at about the right attitude, but much higher in the water of course.  The dog (“Bob”) is just going to open the throttle to see if it has the right amount of bite.

2 April 2009 And she flies! After a quick couple of circuits round our local field from a hand launch, to check the trims in this modified state, and a smooth landing on the grass, off to the Harbour for a more realistic test.  A minute or so’s taxi tests proved that she steered on the water at low throttle (any more and the rear float rises off the water - all steering lost!).  Then full throttle and off the water in a few feet and some “lazy circles in the sky”.  Landing was so easy: she just glides in on minimum throttle and skims across the water.  Another quick flight to make sure I wasn’t dreaming, and same wonderful results.

You lovely, lovely Sopwith!

[Home] [Sopwith] [Other WWI] [Golden Age] [WWII] [Post-War] [Plans for sale] [Wizard show Chaps] [Modelling Articles] [Churchill] [Catalina] [Canadair CL 415] [Depron Scooper] [Auster] [Shoestring] [Duchess] [Welkin] [Sopwith Pup] [DH2] [Grob Egrett] [Fun Cub] [Minimum Mustang] [Type Histories] [Links]