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-   -   Starting a VW. (https://www.pprune.org/private-flying/392427-starting-vw.html)

ExSp33db1rd 15th October 2009 08:20

Starting a VW.
 
Does anyone else have to start a VW powered aircraft, e.g.. Turbulent, with the Mark 1 Hernia Inducing Armstrong starter ?

My Turbulent has no electrics, so no starter motor, and no impulse magneto, and for those who can remember the 1200 cc Beetle of the 1960’s, it was necessary to crank the starter over, and over, until the beast sprang into life, but of course I can only get one compression at a time, at a time, at a time.

On purchase, I was told to prime the carb., throttle cracked, pull full choke, vigorously swing 8 ‘blades’, select half-choke, one mag. on, swing the prop again and Bingo ! Not so.

I have tried all variations of choke and throttle, and one or two mags. and after 8 blades kill the choke, advance the throttle, swing 4 blades to induce some air, and/or inject neat petrol down the carb. throat, use an aerosol can of ether Engine Start, etc. etc,

I usually get an ignition almost immediately, but with a potential knuckle breaking backwards movement of the prop,. after which nothing again until I try a whole new procedure, and I always, eventually, get the beast going, but not because of any consistent method – is there one ?

I have a friend who has built a new Turbulent from scratch, and installed an electronic ignition system that we obtained from the Tiger Club in UK – I hate him - he just stands in front of the prop. and nonchalantly gives the prop. a gentle, two fingered push with no effort. Instant ignition. I could of course convert my engine, I guess, but converting a 40 yr. old 1200 cc VeeDub doesn’t really sound to be cost-effective, and anyway, I’m a pilot, not an engineer, I just want to fly the bloody thing.

Any clues ? Please ?

Lister Noble 15th October 2009 08:53

Not much help but I've seen someone with a VW in a Taylorcraft at our strip swing his nearly all day!
I understand electronics is the answer.
Happy swinging,might go first time today:)
Lister

toolowtoofast 15th October 2009 08:59

pay someone else to swing it for you?
\
Just joking.

The last thing you want to do is feel grumpy and unmotivated towards your aeroplane. You'll constructively avoid using it, which will make you even grumpier.

Make it easy to start - either get the electronic ignition system, or an impulse mag fitted. You will never regret it.

'Chuffer' Dandridge 15th October 2009 09:09

If the engine is set up properly, the following will definitely start it:

Fuel on
Switches off
Full choke
4-6 blades sucking in
Half choke
Set & contact...

If Lucas mags are fitted, the faster the swing, the bigger the spark, the more chance of starting it. There is a special technique to doing this and involves a hand half way down the blade, but not for the faint hearted. If you try and start it using a traditional hand swinging technique, it won't work, as you stand too high in relation to the prop and cant get the prop through the compression.

This worked on all the Tiger Club Turbulents before they were fitted with electronic Leburg mags, which although will start the engine easier, still require the engine to be set up properly (Correct plug gaps etc)

Over or under priming, combined with a poorly set up engine and poor technique and you'll be there all day..

I now have a frozen right elbow after years of starting Turbs, as i was one of the few 'swingers' who could spin the prop over two compressions. Jumping in and out of aeroplanes to start a recalcitrant VW to meet the display slot time was one of the joys of flying with the Turb Team..:ok:

Keep at it, and rest in the knowledge that you are one of the many people attempting to understand the black art of starting a VW:ugh:

hatzflyer 15th October 2009 09:14

This is a real black art! I know, i've had lots of vw powered aircraft and still have 2 at the moment.
There are so many vairiations as they are nearly all home built.
General information... Priming/ choke depends on type of carb fitted,you have to get a really good swing as the mags don't work too well at low revs.
The condition of the coils in the mags is usually the problem, they can test Ok with a meter even when they have broken coils.
Vw's like to be wet to start from cold, but flood easily. Once flooded the plugs will not fire , which just makes them flood more.
Every one has a way that works, you just have to find it!

So.. specifics..What type of mags..when were they last overhauled?
What type of carb..top mounted or below the crankcase?
What type of choke/primer/
Does engine have good compression? Is there any valve leakby( can be heard as a hissing when turning prop at a moderate speed by hand).

How often is it run ( frequent use is the best thing for veedubs) and finally does it always kick back?
Answer these questions and I can probably point you in the right direction.

Edited..Chuffer..not all veedubs have a choke. Leburg is electronic ignition.it is not a mag..that's why you need batteries.

gasax 15th October 2009 10:02

It's a while ago but,
With a high mounted Stromberg, Lucas mags and 1200 engine we found a cap fuel of neat petrol into the manifold and a 'double compression' swing would usually get it going. But if it was really cold - no chance.

When it was hot it had a nasty tendency to kick back.

shortstripper 15th October 2009 10:12

Sounds to me like lack of fuel ... no, really! Do you rely on just the engine pump? With no electrics, I assume so. No amount of swinging will get that pump to suck fuel up to the carb if there is the slightest air leak into the system! Have you checked non of the fuel lines are perished? They don't have to leak fuel to suck air. Are all the Jubilee clips or whatever tight?

Don't use ether ... the engine will get addicted to it! (old wives tle? maybe?)

The exhaust should smell a bit petrolly once you've properly primed ... but not so much so that you feel like you're sniffing an open jerry can of fuel.

Is it worse when not started for a while? If it starts ok after it's been run recently, that backs up the lack of fuel theory. If it's worse when warm, it could very well be the that the mag windings are breaking down!

Good luck, and all power to your elbow!

SS

Lister Noble 15th October 2009 12:10

Following on from priming.
I hand swing a Cub each time I want to fly,as it has no starter/electrics.
I give two primes and pull thru' six blades then contact.Starts first swing everytime but does have impulse mags.

As suggested,maybe a eggcup full of fuel in the air intake will work.
Lister

hatzflyer 15th October 2009 12:13

On lots of vw's you can't get to the carb without de cowling. That's one of the reasons why I have asked the questions above before jumping to conclusions.

Croqueteer 15th October 2009 12:38

:ok:Mine has the Leburg solid state ignition, starts first blade, hot or cold.

Lister Noble 15th October 2009 13:58

Surely the air intake is from outside?
As long as you can squirt some juice into the intake,it should work,maybe not a good idea if it's not outside though,possible fire risk?
Not a VW expert,although I had a Beetle in the 60's.
Anyway I'll leave this to the experts.;)

john ball 15th October 2009 14:19

VW engine starting
 
I had a Taylor monoplane G-BDKU at Redhill, that had the carb underneath and the two SR4 mags on the top. The biggest problem was sucking the fuel up to the manifolds/heads, so we always pumped about 10 times on the throttle before sucking in with a fully closed throttle. Our carb did have an accelerator pump as it was a side draft zenith and no choke. It is very important to have the gaps on the mags, plugs and valves absolutely correct. Also SR4's do wear out and need rewinding. One other thing, if you do not know whether it is too lean or flooded, blow it out by switching off the mags, opening the throttle to full and swing it backwards for 20 fast turns.Then start procedure of normal starting as the others have said in their posts. It really helps to have someone by the cockpit to hold the throttle to catch the engine if it fires.

hatzflyer 15th October 2009 15:12

Most vee dubs do not have the air intake outside of the cowl.lots have throttle pumps, lots don't. I repeat why keep guessing? This guy has asked for help not wild guesses.
Until we know the engine details it is impossible to give sound advise,hence the questions above.:ugh:

Them thar hills 15th October 2009 16:08

Starting VW's
 
As said, you need to pull the blade from about half way along its length, or just a bit further out.
This assumes the prop is fitted in the right place to begin with.
Plug gaps need to be quite small, usually 12 to 14 thou.
Also, if no impulse mags are fitted (usually not) swing it from well before TDC, and give it a good armful !
No half measures.
The prop needs to be moving quickly before the mag points open. If the Gods look favourably upon you, it should start.....:)

Airstripflyer 15th October 2009 18:56

I suggest you fit a Leburg ignition system. My VW starts first swing.

SlipSlider 15th October 2009 19:47

From my limited experience of starting VWs (mostly attached to VPs), Them thar hills has it right .... check the plug gaps! Manuals for the engine as installed in a car specify plugs gapped at 24 thou, but with magneto ignition the plug gap needs to be about half that ie a tiny 12 thou, with a max of 15; beyond that lie hernias .....

Slip

Sir George Cayley 15th October 2009 21:51

I've owned V-Dub motors in cars and planes. Cars start so easily, gently; you hear it come into life. Aircraft engines are different because you can't keep turning the whole system over.

If all parameters are set correctly, and spark timing imho is vital, then a fairly gently throw of the prop should do it. If you have to work up a sweat with any engine, then one of the fundamentals is out of limits.

In the UK, apart from high summer it's actually difficult to over prime, and if you do - blowing out is very effective, but remember that max draw occurs with the throttle closed.

Also check which mag 'leads' If you start on one, don't just select the one the previous owner said, make sure the wiring and top dead centre make sense.

Given the right fuel air mixture, with a spark occurring at the optimum moment your engine cannot help itself but start. If it don't, then there are things you can do.

Happy swinging and remember - better to be called careful than Lefty!

Sir George Cayley

ExSp33db1rd 16th October 2009 07:36

Airstripflyer and Croqueteer - I hate you !! - but add you to all the others that I wish to thank sincerely, all sounds good.

Not at home at the moment, will digest all suggestions and reply in detail later, many thanks.

Not long ago I attended an organised landing on a local beach, but decided not to stop the engine in case the tide beat my starting technique - but as I was stationary realised that a slight vibration from the idling engine was causing me to ' shimmy ' lower into the sand. I decided to go home whilst I was ahead !! Good fun tho'

I vowed never to fly without a Flt. Eng. on board, and never did - until now, when I are one ! When I win the lottery I'll employ an engineer who will have the Turb. outside the hangar, cleaned, engine idling, and will drive up, climb in, wave the chox away with a vague " see you in a hour, have a cup of tea " - but will I have so much fun ?? be nice to find out !!


Regards ExSp33dbird

hatzflyer 16th October 2009 09:03

My Vee dub now starts first swing every time. lucas mags, tipsy nipper.Still experimenting with the D9 though, not quite perfect yet!
A regularly used veedub can be made to start easily and reliably as have many that I have owned.It sometimes takes a bit of time to perfect and is very dependant on the set up hence my questions above.
If you give me your details I am almost certain to have owned a similar set up ! (have owned lots of planes).:ok:

Sir George Cayley 16th October 2009 18:28

I've heard that Leeburg Electronic ignition kits are still available Worth the few quid.

SGC


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