748 Queries

[Tomliner]

I've been spending some time recently on the 748 with Fraser's excellent new panels and sounds and was wondering what causes the brief but distinctive 'whooshing' sound from the props as the rpm passes through 12000 approx.I assume that it's either resonance as the pitch changes or maybe the tips going supersonic.Something similar can be heard when,for example,a Saab 340 commences it's take off.
Also wondered if there are any airworthy748s remaining anywhere.I know that there are still some ATPs still flying. EricT

[Garry Russell]

That is probably sonic effect. IRL Heralds used to chatter in some atmospheric conditions as the tips went supersonic.

748's didn't chatter like Heralds but sometimes had a rasping sound like some piston type with high tip speeds...like a Harvard but not so pronounced or loud.

A few light aircraft can make themselves known

There are quite a few 748's still flying, notably in Canada and South Africa.

[Dev One]

Viscounts did it if I remember correctly when pitch changing to/from ground fine.
Keith

[Garry Russell]

The Viscount use to give off an nice growl on taxiing as the fine went a little negative...seemed often to be when it went uphill at the local

[WhisperJet]

Also wondered if there are any airworthy748s remaining anywhere.

Quite many of them!

Browse through the pages and note the dates...

http://krz.ch/P9pr

Cheers,

Nick

[Tomliner]

Many thanks for the info gents.It doesn't seem that long ago that I used to see Viscounts,Heralds,748s,F27s and Vanguards at East Mids EricT
ps not forgetting the occasional Electra and Argosys(Argosies?)

[Garry Russell]

There is at least one Electra still...poss two at times at EMA

[Tomliner]

The Electra's Alison engines have an unmistakeable sound Garry. EricT

[Garry Russell]

They do , and quite unlike the C-130

[Dev One]

I'm trying to remember the settings that one had on the Viscount - as an apprentice I spent a short time assisting the engineer adjust the micro switches & stops on the control rods under the floor - I also would need to find my 1950's 810 series Technical Training notes that I still have tucked away somewhere.....
Keith