HAFU Harvard

[J0hn]

What a racket!

http://youtu.be/ZZ-Ifl9qViU

[J0hn]

I just found another interesting looking documentary on YT - but this one is 1¾ hours long, so make sure you have time:

http://youtu.be/HHbGbfOaaRc

The Air War Over Germany - one part of a WWII series.

[Airspeed]

Hi JOhn ,
There was a couple of them at the Moorabbin Air Show 1994.
They had been part of a larger group competing in an air race in Tasmania.
That characteristic harsh clatter was due, they said, to the tips of the props continually breaking the sound barrier.
I took them at their word.

[petermcleland]

What a racket!

http://youtu.be/ZZ-Ifl9qViU

I think the prop tips get near to supersonic and that make the racket...The American ones sometimes had slightly longer props and they were even noisier. BTW that video was a very pleasant surprise for me as I flew with Peter Beaumont in that Harvard at Ardmore, NZ in about 1987 or 88

[J0hn]

Ah, I see.

I was a little surprised, as, having never seen one flying, I remembered having seen plenty in various films (usually dressed up as something else) but they sounded nothing like this.

Perhaps unsurprisingly, given that it would have had most people in the theatre covering their ears!

[Dev One]

I should think that the pseudo Zeros using T6's had post prod sounds added!
I have heard Thruxton Jackaroos make a similar sound when flat out - they had larger dia props than the Tigers they were based on.
My father also said that the UK Harvards had their props cropped to reduce the noise, but probably also to reduce metal fatigue on the tips due to the supersonic tip speed. Somebody didn't do their calculations correctly in the design stage methinks!!! Prop efficiency drops off alarmingly above Mach 0.7 at the tips.
Keith

[petermcleland]

I remember while doing my "Wings" training on Harvards at RAF Feltwell in 1951-2 that they were capable of rattling windows in buildings as the plane of the prop passed through the building. It was a very strong resonance