Thursday, 16 September 2010

A slight technical hitch!

The 2010 UK speed championships was held on the 11/12th of September and I ran Black Knight on the Saturday afternoon. Here is a pic of the prepared car


Everything went well for the first run and I managed a speed of 151.51mph. Here is a short video. I am waiting for the better one to be delivered

http://www.youtube.com/watch?v=CB_moXZ2DTM

The next run I installed the ignitor in the rocket but it was a different type with no groove in. The groove is to allow the expanding gasses to escape. As the rocket was ignited the gasses built up inside the motor and had nowhere to go so it exploded destroying the car. Here is a pic






I am in the process or rebuilding the car with a few upgrades.

Watch this space

Cheers

Friday, 16 July 2010

Preparing for the 2010 RC Car Speed Championships

I havent been around for a while but I have been working on the car. The car is basically the same since the last run and I am optimising it for speed. I have installed a new ignition device with a remote relay to fire off the chrge to ignite the rocket. I can now fire the charge from the 3rd servo. I tested this and it works great!

I have fitted a large 3ft X type parachute that is deployed using a small charge of black powder. This has been tested and works good stopping the car almost instantly.

I have tested the car and I managed a speed of 189mph on the radar gun. This shows that that 200mph is in reach with this setup. I will be preparing the car with a fuel load and run up for 200mph for the 2010 UK speed championships on September 11/12th.

Nic Cas is also preparing a car and will be running on August 15th 2010. He is also trying for 200mph. Friday 13th of August might be a good day to try for 200mph!

I have the parts for the upgrade of the Black Knight into the Black arrow. The names are following the UK rocket program of the 1950-60s. The next design uses a 54mm rocket motor 450mm long with 40lbs of thrust for 20 seconds. I will use the original accumulator but fit 2 external N2 tanks feeding the accumulator through a regulator to deliver a steady 750psi through the burn.

The problem for the next rocket is the line of sight. This is overcome by the use of an FPV system. I have ordered a long range system and the idea is to fit a camera on the car and wear video goggles to see out of the car in real time. I will test the system by modifying the car with an electric motor and running the length of the track. The track will be a suitable 2mile runway such as Bruntingthorpe. This is planned for 2011.

I'll post some pics and vids as I get them

Cheers

Monday, 14 September 2009

New RC Car Land Speed Record

The UK RC Car Speed Championships were held at Shakespeare County Raceway on Saturday and Sunday 12-13th of September and this was a good chance to run the rocket car.

I prepared 4 fuel grains and had a 10lb bottle of NOS standing by for rocket reloads and the body shell was painted up by Ricks Body Shop in Kinver. He did a fantastic job matching the paint on the original Black Knight rocket.

The first run I loaded the accumulator with a small amount of NOS and pressured it up to 950 psi for a short run to check stability. The car went dead straight and the rocket stopped with half the run up still to go so the rocket coasted over the line at 58mph. A perfect 1st run

Next the rocket was reloaded and a full NOS load installed of 12 oz. This time the rocket fired and hesitated for a bit before launching off into full thrust for the complete run up. The rocket stopped right between the timing beams and the run was timed at 117mph for a new UK speed record

Next run was a copy of the 2nd but the rocket didn't warm up so much and I managed 107mph

On the Sunday I had one more fuel grain left so loaded it up for the final run. I drilled out the injector from 1.5mm to 2mm and drilled the exit nozzle out from 8.5mm to 9.5mm. I then connected the accumulator directly to the NOS bottle and loaded it up with 18oz of NOS. I connected the N2 and pressurised the accumulator to 1100 psi and iced it down and re pressurised again

This time we took the car back another 100ft or so and then let it rip for the run. The burn was much better and the acceleration far higher. As the car approached the trap i could see it sliding around so tried shutting it down but the rear brake made the car crab and it flipped just passed the trap

One of the guys read out the speed.....

163.51mph and a new overall world land speed record beating the 161.34 set by Nic Case in 2008...

YES!!

Here is the video

http://www.youtube.com/watch?v=Up6hDcKrH40

Thursday, 3 September 2009

Shell




Here is the car and the unpainted shell

The body came out OK. A lick of paint and it will be ready to ROCK!!

Tuesday, 9 June 2009

I put the rocket engine into a chassis so I could test it out and here are some pics


I then took it to the drag strip to try it out. Here is a video of the test
The car accelerated much faster than I thought and I didnt have time to react to get it straight. I need to sort out the chassis and bodyshell but it was a great test and am looking forward to the event
Cheers

Thursday, 7 May 2009

Accumulator test

I have managed to put the accumulator together and carry out a test on the rocket. Here is the setup

  • The accumulator piston was moved up to the top so the N2O chamber was as small as possible and the bottom chamber pressurised to 500 Psi
  • I applied 500 psi to the bottom chamber with N2 and attached the full N2O bottle to the top chamber.
  • The N2O bottle was opened and the pressure in the lower chamber was seen to increase to the N2O pressure of 650 psi
  • The pressure in the lower chamber was bled to 0 and this allowed the liquid N2O to decant into the top of the accumulator.
  • The top valve was closed and the N2O bottle removed and weighed to ensure it was fully empty
  • N2 was applied to the lower chamber and re pressurised to 1100 psi. This returned all the N2O to liquid with no gas
  • The rocket was attached and ignited

Here is a video of the test. The main camera didn't work past ignition but it was captured on my mates phone

http://www.youtube.com/watch?v=CoxqtbEjmk8
The results were as follows

Thrust = 12-15lbs
Burn time 12 seconds

The fuel grain was all gone and it was pretty obvious the injector was too big. The next test will be with a smaller injector and maybe 1/2 the N2O

Saturday, 11 April 2009

I tested the accumulator today to 2000 psi and it was perfect. Here are a couple of pics



I also managed to calibrate the pressure relief valve to 15oo Psi and also manage to find a small regulator on the net to reduce the input N2 from 1800 psi to 900 psi. I will complete the system next week and test it to measure the thrust and burn time