Chorus Gull Float Conversion


My workshop is now so packed with models that, whenever I build a new model I try really hard to dispose of one. So it was that when I set about the DH88 Comet, the Chorus Gull was earmarked for disposal. As the time drew near to put it up for sale, I found myself considering why this model wasn't getting flown very much. I soon realised that it was nothing to do with its condition or flying characteristics. Indeed, it's coming up to its tenth anniversary and still looks pretty good and it has alsways flown well. The issues lie with the ground handling - that long, leggy, raked and spatted undercarriage always seems to result in bouncy landings and the fixed tailskid means that taxiing is a frustrating experience too.


As it happened, my local club had just secured flying rights at a local reservoir and I had been intending to try to work out a float option for the Astro Hog. Eventually the penny dropped that I could avoid the hassle of swapping the Hog back and forth from wheels to floats by fitting floats to the Gull permanently.


The project got off to a bad start: I ordered a set of floats from China. They took a long time to arrive and one of them leaked. They were also a bit heavier than I had anticipated so, rather than botch repair them, I sent them back - at significant (non-refundable) expense, I might add. At this point a fellow modeller took pity on me and offered the pair of floats you see in the pictures. These had been passed to him by another flyer, who had got them from someone else who. . . well, where they originated is lost in the mist of time.


A quick bouyancy test showed the floats to be well matched to the model and I then spent several days scraping off layers of congealed paint and goo from the 16 wheel collets that secured the floats to a positive birds nest of wire work. With a mixture of brute force and penetrating oil the floats were eventually liberated and the job of fitting them to the Gull could begin.


The front mounting was relatively straightforward: I bent up a couple of new torque rods out of 1/8in wire (one size thinner than the land legs) and sleeved the inboard ends with brass tube so that they were a snug fit in the original mounting blocks.


The rear mount was a bit more problematic. I wanted to fix the rear stay with P clips under the nylon wing fixing bolts. However the mounting blocks on the floats were well forwards so, with the step of the floats positioned at the recommended point (under the cg), the rear stay was raked severely forward. So much so that exerting any downward pressure on the model caused it to 'sit down' as the rear stay rotated forwards into a horizontal position.

In the end, I compromised on the float position as you can see in these pictures.

With an extra piece of wire fitted through spare holes in the floats to stop the rear legs from splaying, and an ounce or two of lead added in the nose, I decided to give the model a test flight in this form. The model sat well on the water and took off with no trouble. Flying performance didn't seem to be affected unduly by the floats and alighting smoothly on the water was a lot easier than it ever was on grass! Taxiing was still hopeless though - time to work out a water rudder.

The rudder mechanism was based on a commercial aileron torque rod I had laying about. The rudder itself is laminated from two pieces of 1/32in ply either side of a 3/32in balsa core.

The rudder and the 1/8in ply mounting plate were covered in silver Oracover for waterproofing.

Because the model tended to swing left due to that large wooden prop, I fitted the rudder to the right hand float so that the drag would counteract the left turning bias.

My original plan had been to mount the servo on the float but I didn't fancy the job of waterproofing it so instead tucked it away in the cooling air exit on the underside of the fuselage. These pictures also show the fixing of the rear stay with clips under the wing bolts and the revised stretcher wire, soldered across the rear legs.

The servo is really a bit small for the job and the snake isn't the smoothest. However, the rudder works very effectively and I think the model looks pretty good on the water and in the air.

A few people have said that I ought to re-paint the floats but I'm in no rush to do that - the yellow is growing on me! Meanwhile, I will enjoy the Gull's new lease of life. Of course the original storage problem remains so the Gull has become the first model to be stored outside in the garage. At least that means I can hang it from the wall in one piece, ready to go.