Worlds Largest RC Model ARFF

It is hard to see from the photos but we have added so much more to the ARFF.

As well as the two firemen sitting in the cab we how have a firewoman. Fire fighter Barbie has joined the team so now officially firefighters.

The ARFF now has a dash mounted air radio system so if the truck is out at a show which is based on or near an airfield we can tune into the air traffic of that airport.

The CAFS system not been improved significantly. As well as the air compressor to agitate the foam mix we have now added a pulse solonoid to further mix the foam/air and water mix. 

New wheel hubs have also been added although the picture above might be an older photo with the original hubs, sorry.

After doing a couple of shows I noticed that the front suspension was not working correctly, diving to much so new firmer springs have been added.

As the world largest operational RC Model ARFF we have been to a number of shows now and it has been great to get the public feedback on the model and all the details that have been taken from the real trucks. 

The ultimate photshoot is still going to be to get this truck parked up next to the real thing on an airport runway. 

ARFF Complete. World largest RC Model working ARFF.

At last the time has come to get out and test the ARFF's fire extinguishing capabilities. I have already upload some video to my YouTube channel so you can see the first fire tests.

The boom has now been completed as well as the hose reel behind it on the top of the engine. 

I also have a emergency light which can be raised and lowered on a sort of telescopic boom.

Mirror covers have been added as well as a new lower hose nozzle and top hose nozzle assembly.

New light added at the front on the top hose system.

I have had to add another reciever so we are now up to three with all 24ch being used. 

Mini linear actuatro used to raise and lower the boom,

New 4WD tensioner added, we will see if it works.

So what is next. The aim is to get it out to events across the UK and try and raise some money for charity. I also want to setup some photo shoots with the model next to the real thing.

There are still loads more Fire test videos to come. What size fire can this unit put out?

Upgrades to the ARFF

 When I first designed the ARFF I designed a boom system to house the top nozzle, however as the build progressed I decided not to use the boom and instead go with a top water canon. I have now changed my mind again and decided to go back to the original design with a boom. The design is very different from the original drawings and much, much ligher. It uses four linear actuators running at 30mm/s with a combined lifting force of about 8kg. The unit will be bolted into the same area as the top canon so there is little to no modification needed to the ARFF top plates.  

The lower nozzle has also been modified and runs the foam system which is now working due to adding a foam concentrate injector pump and switching solenoid. All I need to do with the lower nozzle is play around with the nozzle config to change the water streams.

The top nozzle mounted to the boom will pan and tilt using mini servos.

The boom is made up from lightweight materials so the actuators should not be taxed to much.

It uses a simple mecahnism similar to the real thing just scaled down. 

Four linear actuators will be used to move the boom assembly. Each runs at 30mm/s and can lift 20N.

World's largest RC Model ARFF, nearly complete.

Nearly complete 

There has been loads of progress on the build as you can see from the pictures. I have started some weathering of the paint but this now needs to start fully. The belts on the 4WD system seem to be holding but if not I do have a plan B. I have added a few more lights but still have not got around to the red rear lights. The water pump system has had a major upgrade. I have moved from one to two pumps connected up in series. The system is switchable so I can either run a single or dual pump system. The pumps are connected in series each offering a 5l flow rate but combining them like this increase the head pressure and looks great. The lower sprinkler system infront of the front wheels is not working very well and I think if I want to keep this it will have to be powered from its own separate pump. I am having a syphoning issue which is taking power from the main lower nozzle pump.

The main thing that has been taking all my time if the foam system and I have still not got there. 

By adding two mups in series I have significantly increased the head pressure which helps with the foaming. I think my issue is not the eductor where the foam and water is mixed, the foam mix coming out of the top nozzle foams up well when brushed away. This leads me to think that the foam/water mix is not getting enough air through aggitation. To solve this I have created new nozzels which help with this and do work, to a degree. The probelm is that they put loads of foam over the cab which I dont like. If I decide to keep the foam system then I will change to the lower nozzel and spray water from the top.

This way I can reduce the head pressure with the foam flow and it should look much better.

Lots more experimantation needed.

I am now running a full working GPS system and 5.8ghz camera systems and telemetry.

4WD belt system works well. Hub caps printed and fitted.

I have fitted smoke generator to simulate the exahust. I am not sure I will use this a great deal at events but it is in there and looks good at startup.

Rear lights still need fitting.

Dual pump system now on both sides, pumps running in series offering 5L/m flow rate. Max PSI on the system is 100psi. 

The top nozzel can now send a stream of foam about 5m from the front of the cab and the same for the water stream from the lower nozzel. Flow rate looks about right at 5L/m

New seals on the doors keeps all the water out and work well.

Still need to do loads of work on the weathering and making it look good for the cameras.