Who's Pup

[J D 8 - Moderator]

As per title can anyone say possible maker/designer/plan of this largish Sopwith Pup, Quite an old model I recon. Donated to club, probably someone's pride and joy at one time.  Span 77 inch 5ltr oil can for size comparison. Club Chairman thought I might like but size [ only be able to have just it in the car] and likely rigging time at the field putting me off.

[Robin Colbourne]

Its probably the DB Sport and Scale Pup which is 77" span.

The Mick Reeves Pup is  79.5".   Sarik also do one at 79".

Edited July 11 by Robin Colbourne

[William Macleod]

Looks great

[William Macleod]

Would fly well on a laser 180

[Simon Chaddock]

Nice.

Of course like all model Pups the nose is too long.

Even electric struggle when the batteries are squeezed into the cowling.

It does rather show just how relatively heavy the period rotaries were and how lightly built the tail end was.

[Don Fry]

Equally how heavy we build the backend. Anyone done a weight cost of balancing a 2 mm Clevis on the back, rather than on the servo, on the CG. Bit of thought saves a lot of weight. Or indeed, going modern, glue 2 sheets of 1/16 top/bottom to an 1/8 foam core, and cut it to strips as necessary. Other sizes exist. 

 I’ve flown the DB version. Lovely thing to fly. 120 OS pump, tank over moter, heavy bits of radio system moved forward.

[Nigel Dell]

Neil Tidy flew his on the original Laser 90 back in the day.

[Robin Colbourne]

When you look at the tail surfaces of Sopwith aircraft, it is hard to believe just how spindly they were.  Here is a cutaway drawing of the Pup and a photo of an uncovered Camel tailplane.   Noting this and the fact that the rotary engine puts the cylinders right next to the propeller (no carburettor betwix the two), it is no surprise that most models of rotary engined aircraft come out tail heavy.

Edited July 12 by Robin Colbourne

[Mike T]

Pretty certain the OP's Pup is a DB, if it's 77" wingspan. 

 

The cowl is overlong, but can be shortened if, early in the build, you set back bulkhead into the fus., as I did with mine.  You don't have to take much off to make it look quite acceptable.  As much weight as possible is forward, including servo, ign. and rx batteries (plus a chunk of brass bar as ballast).  Even so, it's still a bit 'tender'...

[J D 8 - Moderator]

 Model is in ok order considering it has likely sat in a shed a long time, issues are both top aileron horns have come adrift, small damage on a wing tip, tail skid missing. More of an issue maybe the rather warped tail plane. Cowl has a great chunk of lead in the bottom and there is a dummy engine. [not in pic] A new light tail plane would be a good thing I recon.

[Mike T]

22 hours ago, J D 8 - Moderator said:

 A new light tail plane would be a good thing I recon.

Forgot to mention that I built the tail surfaces to scale outline.  That saved weight, but probably didn't help the slight pitch-instability 😏