PFM Vampire

Kit Review by Trevor Hewson

(Originally written in 1991 for 'Sloping Off', the Newsletter of the Christchurch and District Model Flying Club)

If I were to divide this review into two parts on a time basis, then the first half would be devoted entirely to the difficulties I had in obtaining the kit. Suffice to say that this Pat French design is out of production (it took me three months to discover that!) and so it was a case of trying to find one on a shelf somewhere. When the kit eventually arrived it was clear that it had indeed been on a shelf for some considerable time. The balsa could politely be described as "well seasoned" - dark in colour, dry and hard. Some of it, notably the tailplane, was also rather heavy and had to be replaced. The main components in the kit though are the two part polyester/glass moulding for the centre pod, a bubble canopy and a pair of veneered foam wing panels. the wing panels are nicely made, with the servo bay pre-cut in the centre, ailerons already cut out and snakes installed. A hardware pack is included together with ply plates and dowels to make an elastic band fixing for the tailbooms.

There are no separate instructions or parts lists, but there is enough information on the plan to make the construction clear. however, the more I studied the plan, the more I became concerned by what I saw. As well as rubber banding the booms onto the wing, the tailplane and fin assembly is also banded onto the booms, with the elevator drive being by an unsupported wire pushrod emerging from the centre pod exhaust. now I am by no means a purist, but this arrangement seems to me to be both unsightly and potentially rickety. The tailbooms themselves are a simple box section. this leaves very little scope for rounding off and no attempt is made to reduce the width of the booms towards the rear, let alone to fair them into the base of the tailfins. For me, the picture on the box usually represents an ideal that I can't hope to match, but in this case it represented a basic, not to say crude, model on which I was determined to improve. The artistic impression also suffered by the emergence of those pre-installed aileron snakes on the top of the wing.

The first decision was to forget about all those rubber bands and make this a one piece model. The control runs were the next challenge. I wanted to use the neatly cut servo bay in the sing root, so a spanwise pushrod was routed to a bellcrank in the wing to connect to a snake built into one of the booms, finally operating the elevator by a small torque rod. For the ailerons, I made up torque rods from 12swg brass tube with L-shaped pieces of piano wire in each end. "Golden Rod" outers act as supports and pivot tubes. All of this added considerably to the building time, but did result in all linkages being completely out of sight and I am well pleased with the outcome, although there is considerable flex in the long aileron torque rods.

The tailbooms were tapered and triangular strips added inside each corner so that they could be thoroughly rounded off. This transformation of crude wooden boxes into shapely aerodynamic structures is always one of the most satisfying stages of construction and again I found the extra effort to be well worthwhile. The rest of the model was built to plan and would have been very quick and straightforward but for the fact that hardly anything fitted! this kit has been around, on and off, for many years and gives the impression that some of the templates have been drawn round once too often. The leading edges, trailing edges, aileron facing strips and wing tips are all not quite deep enough, and the fit of the centre pod is a bit hit and miss. Nonetheless, after much filling and sanding, it did go together - so now it was time to phone Peter.

I had decided that this would be a good model on which to try my hand at all of those finishing techniques that I have hitherto fought shy of, notably glass skinning and paint. You have no idea of the effect that that last word has on my confidence - I am a real disaster with a brush or spray can - and do you know anyone else who can make clear varnish dry out looking like rock salt or who causes skinning epoxy to erupt out of the pot and instantly solidify into a foam sculpture? However, with Peter's help and guidance, the model survived and I learnt quite a lot in the process. The wings, booms, fins, tailplane, elevator and ailerons were all glass skinned separately. After final assembly, the model was sprayed with grey filler/primer, followed by silver cellulose. Finishing touches were applied with the aid of yellow Solartrim, waterslide transfers, rub-on lettering, trim tape, and a head 'n' shoulders pilot. In fact that last sentence glosses over a few local disasters (unsupervised use of a brush again!). With a few ounces of lead in the nose, the finished model weighed in at 3lb 9oz - a touch heavy for a mere 52" span, but not out of the way for a PSS model. However, the proof of the pudding....

The box proudly proclaims the model to be "for strong winds". As if to underline the point, a supplementary sheet gives details of how to install a .40 up front! As luck would have it, after a near calm Easter Sunday, April Fools' day brought a freshening Southwesterly so I set of for that favourite site for maiden flights, Bulbarrow Hill! (Note for non-local readers: This hill produces great lift - all the way up to the barbed wire fence, shrubbery and radio mast which are where the landing area ought to be.)

With a one piece model one can't really drag out the preliminaries too long, so, after a quick range check and control check, Brian gave the Vampire the heave ho. The model's first reaction to being airborne seemed to be that it preferred the ground! A sharp snatch on the stick changed the ballistic trajectory into a big dipper flight pattern while I fumbled for the elevator trim. Once trimmed though, both the model and I settled down and, in order to stave off thoughts of landing, I set about enjoying the flight. With each manoeuvre, the Vampire seemed to get better. Rolls, loops and inverted flight are all easy, the model turns smoothly and fly bys can be done at a wide range of speeds, rock steady and totally silent. A bit disappointing that last bit - I must fit a whistle! At this point the lift faded and I had a quick go at landing. This merely demonstrated that, having now got used to being airborne, the Vampire was not at all interested in coming down - I think touch and go's could turn out to be this model's speciality!

The lift was now back with a vengeance, so it seemed prudent to check out the stall characteristics before any more landing attempts. the best description of the stall is "Thing-like", the ailerons carry on working whilst full up is held - very reassuring. Heartened by this discovery, I hauled in a little more up on the next landing attempt, shed some speed with a clumsy turn, and the model after a few bounces, finally succumbed, slithering to a halt halfway down the hill.

Subsequent flights have confirmed the first impressions. The Vampire is at its best when moving on a bit, when it looks good and is easy to fly smoothly. Its forgiving low speed handling is a bonus when it comes to landing on some of our more cramped slopes and, after all the criticisms of the kit, I am pleased to say that I am delighted with the end result.