BBMF procedure?

The main reason would probably be that if the aircraft is outside and it rains there will be one hole in the spinner at the bottom for the water to drain out of instead of pooling in the spinner and leading to corrosion. Thus a four blader should be parked in the + rather than x position.

Slight digression, but qualifies as a strange-but-true…
For anything with a two-blade wooden prop (not on a Merlin engine, I know!) it’s quite important to leave it with the prop blades horizontal. Otherwise the moisture in the wood seeps down into the lower blade if it’s standing for any length of time, and this will cause quite significant out-of-balance vibration.

Has anyone noticed what the BBMF does with its four-bladers and five-bladers? the idea of leaving one of the blade apertures pointingstraight down is a good one, it lets out he water if water there is, and also makes it less likely that some small creature can make a nest in there!

Thanks DB and Fluffy;- I knew this would be the place to ask!

Propstrike Yes we do operate from grass strips although not often, Duxford and Middle Wallop are the ones I remember.

Propstrike – the BBMF has operated from Middle Wallop in recent years – grass runway so I guess the answer is yes they do take grass!

Is there less chance of walking into one blade?

That’s another good reason, with a B-25 leaving one blade sticking straight up puts the other two at the correct head-hitting height for a nice headache. With one straight down the other two are out of the way and you’d have to be really blind to miss the vertical blade! :rolleyes:

As for making it easier to swing the props prior to startup, I recall that having them at an angle does enable you to use your weight to help get things turning. Believe me: that is very much appreciated at such a time!

Mark , Thanks for the photo; I am guessing that you might also have seen that article by Peter Arnold.

Still no answer on the grass-landing question. Usernamechanged seems to have some association with the BBMF, surely he knows.

‘AB910; Though never at Henlow, it was re-sprayed at Luton, presumably because of the restriction on grass landing for the Memorial flight’

Here is a shot of AB910 being prepared for painting for the BoB film at Luton in April 1968.

Hard to imagine now, but in those days you could drive round the side, park and just just walk in the hangars with zero security.

Mark

With a radial we turn them over by hand to ensure that there is NO oil in the lower cylinders which could cause a hydraulic lock and do big $$$$$$ damage 😮 to the engine….most large eningines are turned by hand to ensure that all is clear and nothing is going to cause a hick-up when you engage the starter…the procedure of aligning blades is known as “dressing the props” for obvious reasons…blades up or blades down have many causes from that’s the way I want it to can I reach them and also on some fighters we put the blade up for towing etc….

Apart from being neat and military, dressing the props also ensures that any water that may be in the spinner drains away. This eliminates the risk of freezing and damaging the pitch change mechanism.

And another question;

I have been re-reading a very comprehensive article in Control Column (Vol 2 no 6) about the standisation of the Spitfires’ ‘make-up’ on BoB film.

September 1968 – Tempus Fugit 😉

Mark

“Dressing” the propellers is a time honoured tradition, in the RAF at least – especially when on public view. Makes everything look military, organised and neat. As to there being any engineering reason for it, I cannot comment.

And another question;

I have been re-reading a very comprehensive article in Control Column (Vol 2 no 6) about the standisation of the Spitfires’ ‘make-up’ on BoB film.

‘AB910; Though never at Henlow, it was re-sprayed at Luton, presumably because of the restriction on grass landing for the Memorial flight’

Does this restriction still apply? I am trying to recall if I have seen them operating from grass in recent times and cannot really be sure. When the Hurricane had its problem at Duxford this year, was it exiting the hard runway? I am sure someone will know.

Hi Tony,

From my very basic understanding I think that the same Y position is used for a radial engine as it makes it easier for the groundcrew to swing the props, to ensure that there is oil in the cylinders before start up, but for an inline engine such as a Merlin its presumably more aesthetically pleasing…

Regards,
Snaps

Is there less chance of walking into one blade?