14 minute read
STARTER’S ORDERS
into the front of a building where the doors or windows may be open or opened. Also ensure that no other aircraft is parked behind which may be moved or damaged by the propeller wash on starting.
If the aircraft is parked on grass then consider the surface where the person starting will stand. Is it uneven or covered in stones or other loose material? That can be potentially damaging to the aircraft if it is caught in the propwash and if the surface is wet or damp, would that cause a slip hazard? It is not worth taking a chance, the risk of slipping, damage to the propeller, or injury to the prop-swinger is too great. Move the machine to a more suitable location.
Remember that if you are starting an aircraft on tarmac, the opportunity for the machine to roll forward is increased. Also, chocks may not grip the surface and should be checked for their ability to restrain the aircraft. Curved chocks will work better than triangular unless the base of the chock has some form of tooth to dig into the surface.
You’ll notice I’m not even mentioning brakes here. Many vintage types of course don’t have them anyway, relying on the chocks while starting and the drag of a tailskid for braking while taxying. However, even if an aircraft is fitted with a parking brake, I wouldn’t trust it, particularly if starting solo. I prefer to have chocks in place as an added insurance that the aircraft won’t move forward unexpectedly.
Preparation
The person starting should check their own clothing to ensure that jackets are securely buttoned, zipped or removed, and scarves or any other loose items are either tucked securely in or removed to a safe distance. If wearing a cap ensure it is secure or again remove it and place it at a safe distance. A cap blowing off in the wind could distract the person just as the engine fires, putting them in a dangerous position.
Remove rings from fingers as these may not only cause injury but can damage the propeller, especially if it is wood or laminate. Footwear can be important as sandals, flip-flops or even shoes with loose laces can constitute a hazard. It is recommended that shoes should be worn which provide good support and grip and are securely attached to your feet.
It is also important to recognise the stature of the person willing to swing the propeller relative to the aircraft propeller. A machine such as the Tiger Moth may have the blade in a position too high for a shorter person to comfortably reach, which would put them off balance during the operation. Equally a tall person attempting to start something like a Jodel Bébé, may be off balance and, by leaning forward, could place their head in line with the prop blades as the engine starts. If you are in any doubt about your balance and ability to move clear at the end of the swing, do not even think of attempting it, your life is worth more than the risk.
Above Thumbs up – Switches ON. Starting the BE2 replica. Having a knowledgeable occupant in the cockpit while prop swinging is always the best option.
Procedures
If a person is to operate the controls from within the cockpit, the person starting the machine must remind them that as they are working at the dangerous end – the starter person is in charge.
When prop swinging was the norm, set procedures were developed, primarily by the military, to ensure the person in the cockpit and the person swinging the
propeller had complete understanding of who was doing what and when. Member Nick Radford recently sent us a note outlining the procedure from his late father’s training notes when he was a fitter in the Fleet Air Arm just after the war, and those procedures are as relevant today as they were then. Let’s call the person in the cockpit ‘Cockpit’ and the person swinging the prop ‘Swinger’. The recommended procedure is: ■ Cockpit turns on the fuel, closes the throttle and ensures the switches are OFF. He then gives a thumbs down signal to Swinger and calls out, ‘Switches off, fuel on, throttle closed, suck in’. ■ Swinger responds with a thumbs down and calls, ‘Switches off, fuel on, throttle closed, suck in’ and then turns the prop through to suck fuel through and stands clear. He then gives a thumbs up sign and calls, ‘Throttle set, switches on’. ■ Cockpit sets the throttle and turns the switches ON, makes a thumbs up sign and calls, ‘Switches on, throttle set Contact’. ■ Swinger steps forward and swings the propeller. If the engine fails to start and the prop has stopped against the next compression, Swinger will be able to approach again for another attempt. If the prop is in the wrong position, he will make a thumbs down sign and call, ‘Switches off’. ■ Cockpit will turn the switches OFF, make a thumbs down sign and call, ‘Switches off’. ■ Swinger will reposition the prop, stand back, make the thumbs up sign and call, ‘Switches on’.
If the engine fails to start and it becomes necessary to blow out excess fuel: ■ Swinger will make the thumbs down sign and call, ‘Switches off, throttle open, blow out’. ■ Cockpit will turn the switches OFF, open the throttle fully, make the thumbs down sign and call, ‘Switches off, throttle open, blow out’. ■ Swinger will turn the propeller backwards about six blades to clear the cylinders, and then the start
Below A useful technique when extra grunt is required. Note the prop swingers’ trajectory is forward and away from the propeller. procedure will begin again. It is vital that the throttle is closed and reset to the start position. This is one of the more common ‘gotchas’ so both parties should be absolutely sure that the throttle has been correctly set for starting.
Every type, and even individual aeroplanes, have their own starting techniques. For example, the process outlined in the Tiger Moth Pilots Notes, dates back to the 1930s when for a cold start, the Claudel Hobson carburettor requires a button to be pressed to ‘flood’ the float chamber and allow extra fuel to be introduced to the cylinders. The ubiquitous Continental and Lycoming engines usually use a primer or an accelerator pump on the throttle to pump the extra fuel into the cylinders, while automotivederived engines often use a choke to provide the rich mixture.
Setting the throttle of course is particularly critical. Too high a throttle setting will introduce excess air into the cylinders, increasing the risk of the propeller ‘kicking back’ due to a lean mixture. Of course, if it does fire, it will be at high revs, increasing the risk of
jumping the chocks, or even raising the tail on a taildragger, even if the stick is being held or tied back. Some pilots mark their preferred throttle setting on the quadrant or throttle control so they can have a smooth and stable start. Go beyond it, and things can get exciting very quickly!
The risk of the propeller kicking back is one of the reasons you shouldn’t wrap your fingers over the trailing edge of the propeller – if it kicks back you could receive severe bruising or worse. The military for many years briefed their prop-swingers to use just their right arm, holding their left arm behind their back. However, I find that this encourages me to loop my fingers over the prop.
I prefer to use both hands with the fingers on the front face of the prop only. It does of course mean that you are placing your head and body closer to the prop as you swing, but I mitigate that by taking a step backwards as I swing. The important thing is to, initially, have some instruction by someone with experience, and to listen to their advice.
Some people with aircraft such as Cubs and Tiger Moths, swing the propellers from behind, allowing them to quickly reach the mag switches or throttle if something untoward happens. Again, it is all about developing the best and safest procedure, then sticking to it.
Problems
This specifically applies when things are not going to plan, such as a recalcitrant engine. As anyone who has tried to start an engine, whether a Gipsy Major, Continental, Lycoming or VW, when they are in that ‘not quite hot, but not quite cold’ scenario, one is never entirely sure whether you have got the starting mixture too rich or too lean. The important thing here is again, to stick to a standard procedure. Decide in advance that after so many swings of the propeller, you will turn off the magnetos, open the throttle and turn the propeller backwards to blow out excess fuel. And having done so, you will of course remember to close the throttle won’t you? If you are getting hot and bothered after swinging the propeller fruitlessly for a while, stop. Turn off the switches, close the throttle and walk away for a few minutes. Even have a cuppa, to let the engine get sufficiently cool to allow you to return refreshed and use your proven cold-start procedure.
The chances are that any excess fuel that has pooled in the inlet system will have by then turned into a nice cloud of vapour that will give you just the right mixture to start anyway. Equally important, you might just break the potentially dangerous cycle of swinging the propeller expecting it not to start, then being taken by surprise when it suddenly bursts into life in front of you!
Another important thing is to not be afraid to ask for help. If there is someone suitably qualified around, don’t be afraid to ask them to ‘cover the throttle for you’ or assist in a suitable manner. Do, of course, ensure that they are properly briefed and know where the magneto switches are. I know of at least one quirky French aeroplane where the magneto switch operation (and placarding) took a group of us some time to translate!
I would be very cautious of trying to ‘swing’ an engine which is not normally hand started. It’s almost certain that the propeller is not in the right position for safely swinging, and when it comes to geared propellers, such as on a Rotax, just say no.
My final comment on propellers is, whether they are hand swung or electrically started, always regard them as potentially live. I was certainly glad that I did a couple of years ago when, after checking ‘switches off’ with a pilot in the cockpit, I was pulling through the propeller to suck mixture into cylinders when the engine suddenly fired. It turned out the pilot had accidentally flicked the switches on with his elbow while he was adjusting his seat belts. I certainly learned about flying from that… ■
Top left A runaway at Barton in 2006 – the aircraft was unmanned and was started without chocks after the engine stopped at the runway hold. The consequences could have been much worse. Photo: Alan Mosiezny
Top right Though switches are off when pulling through to prime the engine, the prop should always be treated as live. It would be better not to wrap one’s hand around the prop. Some pilots wear gloves when prop swinging for added protection.
Above A lovely period shot taken at Panshanger in 1948. Surprisingly no chocks are in place, but it does appear that the tailskid may be tied down – a recommended action if the aircraft has no brakes or is unmanned.
Projects which inspire others to build their own aircraft Compiled by Mike Slaughter
Project News
Isuppose I should consider myself very lucky that in early March I was able to take the mower out of hibernation, fill it with dinosaur juice, pull it through a dozen times and coax it into life and cut the lawn. Following the record rainfall of February, there must be many grass strip flyers that would have loved that chore, along with the possibility of flying.
Only two projects this month received their Permit to Test, but a very healthy number have been commenced. I was surprised to see two Sling 4 TSi builds listed, but on looking back through last year, there are at least six ahead of them. It’s an impressive aircraft with its very capable Rotax 915iS, have a look on the internet if you have a spare browsing moment, African aviation does seem to be blossoming.
Andy Best has been working upon his own design ‘Blue Two’ for a few years now and I think it’s fair to say that he is approaching the home straight. I know that many readers are following this project, and I’m always keen to see how he is getting on. A warning though, one of his pictures does contain sunshine and a blue sky, remember those?
Tony Whitehead, who you may recall restored a beautiful and rare Morane Saulnier MS.317, has recently imported his latest project, a lovely radial powered Fairchild, which has been permitted to come onto the LAA register – he makes the process sound straightforward but I’m sure its smooth success is down to his experience and diligence. As I’m sometimes reminded, we make our own good luck!
Opinionated debate
When it comes to a stimulating topic of conversation now that the ‘B’ word is out of the way, then the death of the internal combustion engine and the electrification of transport is guaranteed to provide opinionated debate. I imagine that when Orville and Wilbur made their first flight of some 120ft at Kitty Hawk, the detractors ‘poo pooed’ such an invention as worthless, perhaps claiming a bicycle would travel further and more cheaply. Still, less than 66 years later, mankind flew a quarter-of-a-million miles and set foot upon the moon. Relatively speaking, electric flight within our sport is probably only a little further down the road than the Wright Flyer, but things are changing quickly with technology migrating from that ever so very slightly less conservative industry, the automobile engineering. Our sized electric flight does exist, but is still in the margins with the forthcoming Air Race E competition, Red Bull style competitive sprints and the likes of Rolls-Royce trying to take the electric flight speed record from Siemens with a custom-built airframe and powertrain.
Commercially, Wright Electric (imaginative name) has partnered with easyJet and is developing a pure electric A320 sized, 1,000 mile range passenger aircraft with proposed entry into service this decade.
More down to Earth and practical is Pipistrel, with their Alpha Electro training aircraft that has been in production for a while now, in fact they have recently increased their production from four to six aircraft per month – so someone is buying these six-figure microlights.
New students
With the increasingly vocal ‘green’ agenda, I can imagine that in the near future, a flying school utilising electric training aircraft could attract more new students because of its perceived environmentally friendly credentials, even if those students still drive to their lessons in their internal combustion engined car! Interestingly, some of the above electrified examples employ modular battery swap out as a means of rapid refuelling, which the Wright Electric passenger aircraft also proposes. However, I recently heard through casual but informed conversation that Pipistrel were considering moving away from this model as a result of damage to the storage modules from the repeated handling.
I can think of only one electrically powered LAA aircraft that has been featured in Project News in the last three or four years, so I was excited to learn of Tim Bridge’s current Zenith CH 750 build. Tim, an engineer working on large solar farm projects for many years, has set about building a CH 750 with a difference – it will be purely electric powered – but that’s not the whole story, see what he is up to below.
So, am I off to purchase a Lithium Iron powered lawn mower? I guess so when the current Victorian tech one decided to pack up, especially as I can use my current range of monster power tool batteries in one – but what will I then do with the stale fuel drained from my aircraft…?
To get in touch with Project News, and tell your story, report a milestone or just to send a picture, email: projectnews@laaarchive.org.uk.
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