Brief:
An interesting looking kit - single stage 29 or 24mm motors with single stage parachute recovery using a floating piston.

Modifications:
Recovery system, and motor mount, as described below.

Construction:
One of Missiles for Peacefull Purposes' creations - the Raptor is a truly cool looking kit. I had seen various videos and pictures of the rockets and when Physics of Flight started to make them, I wanted one. I had to wait a while though, before actually getting one - I picked up mine at IRW 2002 from Rockets and Things and had a look through the kit to see if I had all the parts. I was actually missing a payload section eye bolt, one brass crimp and a motor mount adapter centering ring, and started out on the build. The only disappointment was the elastic shock cord, however this was kept, but extended to 12'.

First up was the motor mount (29mm inside diameter) which I made up with some two ton epoxy (the part that I least wanted to fail). It was all fairly simple stuff. The main airframe was BT-60 and the superb quality centering rings fitted a treat. I had to cut a notch in the top two centering rings for the steel cable shock cord and made a noose with it that was fitted between the middle and first centering ring, and then crimped. Just for safety I epoxied the shock cord noose to the motor mount.

Whilst the epoxy on the motor mount was curing, I set about marking the tube for the fin positions. Unfortunately the fin marking guide didn't meet up where it was supposed to on the tube, so I had to take the positions off another Raptor, I did the standard marking on the tube with the door frame trick, which again proved successful and I marked on the positions for the cutting. I didn't get any further on the kit at International Rocket Week but I carried on back at home on the Monday afterwards.

For the tube cutting I grabbed my Dremel and cut away happily, the width of the cutting disk being perfect for the gap of the brilliantly made CNC cut ply fins. I was quite pleased that the fins were "through the wall" as it would provide loads of added strength - perfect for what I plan to fly it on..

Before I epoxied the motor mount I made a small modification recommended to me by Richard Parkin; I drilled a small (1.5 mm) hole for a bolt and nut to be fixed through. The nut was glued on the non-visible side of the hole and the bolt would be used for holding the 24 mm motor adapter in place when flown in that configuration. The modification was very easy and will almost certainly be of great use in the future and in my opinion such an assembly should be included in the kit for this purpose.

The Fins were next; these are superb quality CNC cut ply and really fit the bill for a cool looking rocket that is very strong. I sanded off all bits of shavings left by the machining and sanded down the main faces, just for a little extra finish. I also sanded the leading edge of the fins, for aerodynamics. I epoxied them onto the motor mount with Devcon 2 ton epoxy and also attached the launch lug (a brass PML one rather than the one included) with the same stuff. The launch lug was later filleted and then smoothed off with a car body filler and the ends beveled to roughly 45 degrees.

After the fins were set I filleted the fins with Devcon 2 ton epoxy and left them to dry. This was the longest part of assembly as I clamped the rocket into the vice and did each set of fillets (four at a time) so that they would not drip but be nice and smooth and not leave me having to get my hands covered in epoxy. With each fin set taking about forty five minutes to cure, this took some time.

Next was the Piston Ejection system. The instructions say to peel the top layer off the piston tube and soak CA into it and spread it about. This part has the capability to leave you stuck quite badly to the tube, so I used a pair of clips used for soldering to hold it whilst I did this part. Pliers would suffice. I think that this point should be included in the instructions. When the CA has dried and been sanded it gives a surprisingly shiny coat, but this does require quite some sanding to slide smoothly in the main tube. I found that the steel shock cord was too short to position the piston where it was suggested so I positioned it about 200 mm from the top of the main tube along the elastic shock cord and secured it in place with a knot on either side of the plywood plate and secured with epoxy, and then coated the whole plate and the parts where it touched the piston with epoxy.

I made the 24 mm adapter as instructed but the one centering ring that I had was too small for the 25 mm OD tube. This means that I had to strip off the outside layer of the tube as in the piston and strengthen with CA. The ring, even with sanding, was still a tight fit but I managed to fit it in eventually, and secured it with Devcon 2 ton epoxy.

I also put in the 24 mm engine hook and cut the slot in the large ring for the end of the adapter. I then marked on the location for the bolt for keeping the adapter in place by putting a nail in the hole drilled for the bolt and then lowering the adapter onto it, and then drilling on the point made.

Before painting, any holes and irregularities in the fillets were filled in with car body filler.

Finishing:
The instructions also include a 'painting suggestions' page, which quite amusingly are printed in Black and white ;-) I opted for a nice metallic blue. The rocket has no decals with it but the amazing and funky looks make up for that....The ply fins do need filling before painting to stop paint seeping in and spoiling the effect

Construction Rating: 3 out of 5

Flight:
I've so far only flown this rocket on a D12-5, it was a slow and dramatic flight, only slightly underpowered. This will rock on a G, and will be flying on one shortly hopefully :-)

Recovery:
The recovery is excellent, the floating piston chucks out the chute brilliantly and the lack of the need for wadding is a huge plus.

Flight Rating: 4 out of 5

Overall Rating: 4 out of 5