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RATO Rules OK!
The webmaster is always looking to inject something a bit different into the Carrier mix, so here’s a pre-test-flight preview of his latest silly idea – rocket-assisted take-off!
The root cause for this experiment was the need to get c/l ducted-fan jet outline models into the air as fast as possible – bungee is impractical, a pulse-jet liable to lose me the flying field, so rocketry it has to be!
Was RATO ever actually used on board carriers? Let’s check it out, here’s a few taster pictures…
So let’s look at my Hellcat version…
The setup uses model dune buggy racer Spektrum TX/RX
Estes rocket mounted in a re-purposed Enya muffler body
The modification kit (black box) fitted to the Hellcat (includes conversion to R/C throttle)
--and the true horror of what’s inside that black box!
Blast deflector
First flight attempted last weekend (14th June 2014) – Bob Brock and I got the Hellcat down to the field, swore to observe all safety measures, inserted the rocket into its nacelle, filled the tank and tried to start the ASP which wasn’t keen to run – reason, with the throttle now being servo-controlled, its normal “at rest” position = idle, so it had real problems warming up. So I did the C/L pilot’s 60-foot dash down to the Saxton R/C handle, Bob disarmed the rocket, I inverted the servo control to start = full throttle, ran back, re-armed rocket, started motor – hooray, ready for launch! I maybe I should have mentioned that the grass on the badlands at the edge of the airfield where we fly is currently as high as an elephant (seal’s) eye, so an RoG was out of the question. Bob bravely volunteered to hand launch the plane, and I would try out the rocket ignition in the air after a lap or two. I was just about to re-run the 60-foot dash back to the handle with the motor running nicely when suddenly,”WHOOOSH!”, a cloud of smoke as the ESTES D motor self-ignited, a bang as the rocket ejected itself and a sudden shriek as Bob dropped the plane and started whacking energetically at his smoudering trousers!
Then the fire was put out and he confirmed that the only damage was to the sexy pair of Strides he had on, we both suddenly noticed that the Hellcat’s R/C control box red tell-tale “FIRE” LED was flashing and the throttle servo was exercising itself intermittently, indicating a spurious signal going through the wires that ignite the rocket – there was absolutely NO input from the handle (it was switched off). Best guesses from the R/C greybeards is that the tiny LIPO on the plane was low on voltage, and kept dropping its bind to the Tx, then re-linking itself, setting off the rocket as it reset all the channels to their default positions. A rethink is needed before we try it again!
We did then fly the Hellcat rocketless to test out the RC throttle, starting with default = full, then flipping the channel to reverse when I picked up the handle to set it to idle, to give a natural “squeeze-trigger-to-go-faster” action – works well, ideal for carrier. Then we packed up and slunk off home for a cup of tea. I promised to get Bob another pair of Oxfam flying trousers, but he wouldn’t hear of it – he wants to wear the patch (or maybe the hole) with pride to remember the day he was talked into doing rocketry!
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