HOLD ME BACK.
Last issue of Airborne, Mike Close reported his findings of the use of the Airopult Model Restraint. I also have the same item for my own use and intended to report on my findings but I held back as Mike was first past the post. However, there is no reason why I cannot present my findings as a personal article rather than a product review.
I was first attracted to the Airopult with a view to safe ground management of model aircraft. In the early days it was accepted that a fellow flier would hold your model while you started the engine and tuned it ready for flight. Various problems here. The person holding the model is subject to high speed (force) dust particles into their eyes plus the ingestion of exhaust smoke and oil. As well, will the person pay the required attention to the very important job of restraining the model? What if he makes a mistake and the model surges forward…with screaming propeller heading straight at your lower regions? (Oh - the pain and indignity).
Have you made prior arrangements for your command when the engine is running? Perhaps a nod from you means (to you) that the engine sounds spot on but…it might be interpreted by the holder that he can release the model and it leaps forward and ‘bites’ your leg. Well, generally, we have moved on from the non-paid holder and employed sticks (tubes, rods etc.) in the ground as a model restraint - in some clubs this is mandatory but…what about starting the model? We now see the skin crawling, cringing method of holding the model with one hand whilst applying the starter or tuning the needle with the other hand. All the while the tips of the whirling propeller blades are skimming the air just below the underside of the holding arm and….getting closer and closer as you pay more attention to the starting or tuning operation.
I have seen horrendous accidents involving severe multiple injuries along the modeller’s arm due to the common (human subconscious) reaction in incidents involving propeller strikes during the restraint of a model in this style. To explain - it is a subconscious reaction to pull whatever part of your body is being hurt away for the source of pain…in the direction of which you first extended that part of your body. Stick your nose forward in an argument and you pull your head back when your nose is belted…touch a hot item with your finger and you lift your finger up off the item and so it is with the propeller strike. You move your arm forward to hold the model and the reaction is to pull it back when the propeller makes the first contact. The propeller is spinning at, say, 8,000 RPM and we can move our hand at, around, 15 metres per second so that propeller is going to contact more than once before your arm is clear and this is backed up by the common types of multiple strike injuries that occur.
I do not like anybody near me when I am starting a model engine - either in a model or on the bench as a fraction of a moment’s distraction is all that is needed for a dire result. My favourite method for starting an engine in a model is to use a model frame or stand - the model is held in the stand, started and tuned (a rare moment as I am not a needle twiddler) then lifted off to be put in a position for taxiing and/or taking off. Close to the best method for me but still with inherent problems. I put the TX down whilst I lift the model out of the stand, bend over with a ‘live’ model to place it on the ground then bend again to pick up the TX while the ‘live’ model is champing at the bit, so to speak, to get into the air.
As I said, close to the best method for me but…I am never satisfied with ‘close to’ - I prefer ‘correct’ or best and now I have it with the Airopult - so simple. The Airopult is pegged to the ground (all set out well in the instructions), adjusted to your model size, set up for the starting procedure, the engine in the model is started using both hands on the starter or the ‘music is played’ on your electric canary (electronic circuitry for electric powered models), you then check all controls are functioning ….in the correct directions…, check all is clear, call ‘take off’. Press the pedal at the rear of the Airopult and your model is ‘out of the box’ - and heading for heaven (or at whatever height you fly). How simple and safe is that?
As most readers would expect, I disassembled that which can be disassembled (so… what’s new…that’s what I do with things’) and found the manufacturing and components to be of excellent quality - nothing that would appear to break, wear or malfunction and no corrosion potential. I would expect the unit to last for a long time with 100% reliability.
To close, apart from my recommendation for individual modellers to purchase one for themselves. I also suggest you ‘lean’ on your club treasurer (or committee) to purchase one or more for your club. Convenient and, most of all, ideal for improved safety operation of model starting and testing procedures.