PML Pterodactyl
- Length:
- 104cm / 41"
- Diameter:
- 10cm / 4"
- MMT:
- 1x 38mm
- Status:
- Crashed
Comments:
I bought the PML Pterodactyl Jr from Pete's Rockets for my Level 1 Cert flight. I acquired the rocket at the UKRA 2000 event, with the intention of flying it at IRW a few weeks later. This model is one of the phenolic airframe versions, before Quantum airframe became popular. What that does mean is that there is a spiral groove which needs to be filled if you are a perfectionist, but personally I don't care on a rocket like this. On a scale model I would, but this rocket was intended to be an H-I motor HPR workhorse, and I knew the paintwork etc. would become dinged anyway.
One reason I bought the Pterodactyl Jr was because it was a 4 inch diameter model, which means you can get your hands right inside, and it makes packing the parachute light work. The other reason is because the fins look rather cool compared with many 3FNC rockets. Despite what the Rocksim image suggests, the fins are actually all one piece .062 G10 fiberglass fins. The fins are TTW right to the 38mm MMT, and with the relative sizes of the MMT and airframe, they are a breeze to epoxy and fillet.
Construction is standard PML throughout, and very easy. Firstly you epoxy one end of the piston strap to the MMT, then install the centering rings, then install the entire assembly into the airframe. Next up is the fins, and then finally epoxy the other end of the piston strap to the piston. It really is that simple! All that is left is to decorate it and attach the recovery harness, parachute and nose cone.
Given the relative 'stumpiness' of this rocket and the way the fins are extended so far forward, you would expect it to be marginally stable. In fact Rocksim tends to confirm this, but I have successfully flown this on 2-, 3- and 4-Grain Aerotech and Cesaroni Pro38 motors. Care needs to be taken with the longer motors, because they will stick out the front of the MMT, with the ejection charge aimed right at the piston strap.
Following a thread on UTR regarding motors poking out of the top of MMTs, I thought I'd try to fly this on every possible type of Pro38 motor. I'll probably omit the 1G G motors, and just go for the 2-6G ones. Fitting the 6G one in is going to be interesting, and may need a minor mod to the piston arrangement. Here's the progress so far (not looking so good, as it's flown mostly on AT)...
| Propellant Type | 2G | 3G | 4G | 5G | 6G |
| Classic |  | | | | |
| Smoky Sam |  | | | | |
| White Thunder | n/a | n/a | n/a | | n/a |
Simulation:
Rocksim Simulation Results are available for this rocket. These results have been automatically generated from the Rocksim file.
Flight Log:
| Flt. | Date | Location | Motor(s) | Impulse | Recovery | Comments |
| 1 | Aug 2000 | Largs IRW | H123-W | 230 Ns | PML 'chute | Successful UKRA L1 flight |
| 2 | Aug 2001 | Largs IRW | H123-W | 230 Ns | PML 'chute | Successful flight |
| 3 | Aug 2001 | Largs IRW | H242-T | 230 Ns | PML 'chute | Successful flight |
| 4 | May 2002 | Big EARS | H242-T | 230 Ns | PML 'chute | Successful flight |
| 5 | Aug 2002 | Largs IRW | H242-T | 230 Ns | PML 'chute | Successful flight |
| 6 | Aug 2003 | Largs IRW | I287-SS | 486 Ns | PML 'chute | Suffered windshear at around 3000ft, then carried on upwards! |
| 7 | Jun 2004 | UKRA | I212-SS | 364 Ns | PML 'chute | Successful flight |
| 8 | Aug 2004 | Canterbury Cup | I287-SS | 486 Ns | PML 'chute | Successful flight |
| 9 | Sept 2004 | ALRS V | I218-R | 330 Ns | PML 'chute | Gary Rosenfield prepped the Redline (perfect flight) |
| 10 | Aug 2006 | Largs IRW | H143-SS | 247 Ns | PML 'chute | Successful flight, landed on crag |
| 11 | Sept 2006 | ALRS VII | H242-T | 230 Ns | PML 'chute | Ejection charge failed. Rocket lawndarted and turned into confetti. |
© 1995-2005 A.S.Moore. All Rights Reserved.
