LETTERS

VW ‘Jack Russells’

Ihave just read Steve Slater’s article about prop swinging in the April issue of the magazine. It was spot on – well informed, educational and measured. I particularly liked the comment comparing a VW engine to a Jack Russell terrier and can confirm this from my own experience of hand swinging my Nipper. It either starts first time or temperamentally after a few swings, but it never fails to surprise.

Many years ago, I would swing the propeller on my own, luckily without incident, but with age and experience comes fear and caution. I was at Barton when the Luton Minor became temporarily airborne without its pilot, and I have two friends who have succumbed to serious injury through prop swinging accidents.

These days, I always have my trusted prop swinger with me and I never, ever underestimate the danger of a propeller, even on my diminutive Nipper (pictured above). Kate Howe

Impulse mags and dead cuts

Brian. May I add a couple of points to Steve Slater’s comprehensive propeller swinging article? (LAA April 2020) 1. One should start on the impulse magneto ONLY. The impulse mechanism retards the spark so that kick back is unlikely to occur. If the non-impulse magneto is on and should happen to fire, the kick back will be severe as the spark is not retarded. 2. The magneto ‘dead cut’ check when idling at the end of a flight is important to ensure the switches are operating to ground the magnetos properly. A non-impulse magneto which is not grounded, even though the switch is OFF, will likewise give a sharp kick back. This state of affairs may be indicated by no mag drop on one switch when performing the pre-flight run up, but is best checked by a momentary ‘both switches off’ at post-flight idle.

One learns from experience! Yours, Rupert Hibberd.

Brake check and vacuum pumps

Just read the LA article on hand swinging and would like to add a couple of suggestions. It did not mention brakes, if they are being relied upon instead of chocks. We have got into the habit of testing brakes immediately prior to the ‘contact’ call.

This involves grasping the prop near the hub and pulling forward hard to confirm adequate brake application by the ‘cockpit’ person. I’d never rely on brake latching.

Also, on ‘blowing out’, it’s not advisable to turn an engine with a vacuum pump backwards (and the alternative of blowing out forwards with full throttle is too horrible to contemplate – never trust ignition switches).

However, as the types with vacuum pumps are not normally hand swung, the point is moot. Kind regards, Dave Smith.

A good purchase, at the right point

Hello Brian, I am a bit concerned about some aspects regarding the article about prop swinging, as it states that you should never wrap fingers over the trailing edge of the prop. I do not know how you can get a really good hold of the prop unless you do. I have watched people swinging props by placing their hands on the face of the prop and using friction in order to swing it. This means that a considerable forward pressure is needed into the propeller arc in order to get a good swing. This to me has always looked rather dangerous, as it means that the balance of the body is forward into the propeller arc.

Using friction on the face of the prop cannot give as good a swing as wrapping the fingers round the trailing edge, and the greatest danger of not giving a really good swing is that the prop is more likely to kick back. I have watched people who are afraid of prop swinging give it gentle a swing and only just about hit top dead centre, and this is almost certain to give a kick back. I have always wrapped the first joint of

my fingers around the trailing edge and swung the prop as hard as I can. By doing this it gets the engine well over top dead centre, is less likely to kick back and the momentum of the swing takes my arm out of the prop arc. My ignition is fixed at fully advanced, which should be the worst situation for getting a kick back. My engine does kick back at times but my hand is always well out of the way. I have only been caught a couple of times over 45 years with more than a stinging reminder.

Another point not made at all clear is that a prop should be swung from about one third of the way down from the tip, as a greater turning effect will be developed than from swinging at or near the tip. Also, if the prop is swung from the tip and kicks back, then the velocity at the tip is far greater than swinging further down and could result in some considerable damage.

Swinging a wooden prop at or near the tip will very quickly cause damage due to the wood at this point, it being quite weak – as I know from a number of props that I had to repair. Hope this is useful. Chris Lodge.

Dodgy 2-handers and 3- and 4-bladers

Congratulations to all those mentioned for the article on prop swinging. The balance was just right, and the photos show some of the points raised, but the text did not point them out, especially those on P10 and P11.

I can’t say that I am in favour of the two-handed method as the person shown on P11 is clearly leaning forward into the prop, which is a difficult position to recover from, whereas the person using the end of the prop for maximum leverage (P13) and walking the prop through whilst walking away is the much preferred method, as mentioned.

Whilst the adage of ‘always treat the prop as being live’ is extremely good advice, I think it is equally necessary to say, ‘never put your hand back onto a moving prop’. I see so many people doing this and having had three very near experiences over a long career in light aviation, I have always abided by it and pointed it out if possible whenever I see it. Your comment about starting Volkswagen engines falls into this category, having had that experience with a Jodel D9.

One method which was not mentioned, and one which I have used very successfully, is to use a rope to pull the prop ‘through’ when it is in a difficult position to swing. The photo of the Bentley engine being swung from a crouching position is a case in point and could also be used instead of three men in the photo on P12. It is also the safest and most efficient way of swinging a three bladed prop and the only way of starting a big four blader on a Valetta or Varsity, as we found out on a visit to a civilian airfield where they had no ground power unit to suit it. Keep up the good work. Best, Rod Brown.

Thank you to everybody who has taken the time to write in with additional advice on prop swinging. Like so many things in life, there are subtleties in techniques, above all it is a skill that is learned, so seek out expert advice rather than just ‘give it a go’. Ed.

Eze goes the e-Go

Dear Brian, I read with interest the e-Go article in our April magazine that included mention of the Vari-Eze and Long-EZ canards. In the same issue, perhaps by coincidence, there was also Phil Hill’s article outlining fibreglass work. Without taking anything from the eGo project I would like to extend discussion to the merits of these Rutan types.

These 1970s and 1980s futuristic canard designs have been developed into extremely capable and reliable aircraft, their performance well suited to efficient cruising over medium ranges (700+nm), and Long-EZs have traversed the Atlantic.

I would draw readers’ attention to the very affordability of these aircraft. The Vari-Eze and Long-EZ plans and manuals are still available, although not from the original source. They consist of 24 chapters, and when I built mine, I ordered material for only two chapters ahead – procurement in the late 1970s was not so easy as it is today – so no great layout needed.

Another distinction of the Ezes, and there are many, is the option of classic aero engines. There may be those who opt for the new generation engines but for pure simplicity, overhaul life, reliability, and hence safety, the solid options of Continental O-200 and Lycoming O-235 was another plus when I was deciding what to build.

The ‘plans’ also have a degree of flexibility, allowing an already efficient airframe possibilities to improve further – such gratification for me coming to Denmark where I won the last EuroCAFE efficiency race against more ‘modern’ aircraft. And today of course, there are web groups dedicated to the support of those now building these types.

I think that because the Ezes sit (very stably) on their noses and are canards, many would-be potential owners are put off, they prefer their aircraft to look ‘normal’.

However, we have had many years of touring from Scandinavia to Portugal, and from France to Austria, all in economic comfortable luxury at around 140/150kt economy cruise. When few examples turned up at British air shows and fly-ins, it was said that it was because they were too busy tearing around the Continent!

Although touring is my main ‘mission’, just flying around is an absolute pleasure in my agile little Vari-Eze. In the early years we had as many as five Ezes at my home field, resulting in many happy two to four ship formation lunch sorties. The Ezes are fast, yes, but also safe and forgiving provided you stay ‘ahead of it’.

It took me four years to build mine (five calendar years as I had a work assignment ‘gap’ for the middle year) plus, as one of the first UK builders, I slowed progress in anticipation of expected modifications.

For anyone looking to build a superb aircraft from their ‘wallet’ as opposed to breaking into capital, a bank loan or overdraft, I encourage them to at least consider these extremely rewarding aircraft. Mike Tooze, builder, owner and operator of O-235 Vari-Eze G-EMMY ■

“Swinging a wooden prop at or near the tip will very quickly cause damage due to the wood at this point, it being quite weak”