Friday Gastons Pictures

[Bob Bement]

Oh yea, I remember the 185! sigh....I love the sound of airplanes!

Tristar, It looks like you spent some time around Doctor Burce this weekend.

SIGH! Bob

 

[TangoWhiskey]

I have video of this very funny--and repeatable--occurrence today, but I can't post video from here this weekend...

Every time Dave Taylor took off in his 300hp 3-bladed Bellanca Viking ("The Wooden Wonder") the rumble would set off the car alarm on this truck parked at a nearby cabin...

...you gotta respect that!

I submit Exhibit A:

 

[t0r0nad0]

I submit Exhibit A:

Awesome!

 

[Let'sgoflying!]

I think it was because the prop spins up so high; 2850.
I can't figure out why the C185, in all its awesomeness, did not do the same.

 

[mikea]

WHY do they need (or arm) car alarms in Lakeview, AR?

 

[AdamZ]

I think it was because the prop spins up so high; 2850.
I can't figure out why the C185, in all its awesomeness, did not do the same.

I thought that three blade props are queiter and thus less vibration than 2 blade props. No?

 

[SkyHog]

WHY do they need (or arm) car alarms in Lakeview, AR?

To protect their teeth.

 

[SCCutler]

I thought that three blade props are queiter and thus less vibration than 2 blade props. No?

Adam, what you are hearing is the tips going supersonic; one can often use a three-blade prop of slightly less diameter and larger blade area to replace a 2-blade, with less noise because the 2-blade might have tips going sonic at full-power, while the 3-blade might not.

But, in Dave's case, the tips *were* super-sonic.

Just like Dave.

 

[gismo]

I thought that three blade props are queiter and thus less vibration than 2 blade props. No?

They can be quieter but the chief factor in prop noise is the proximity of the tip speed (RPM*diameter) to the speed of sound and shape of the blade. Three blade props tend to produce less noise inside the cockpit because the 50% increase in frequency makes for more attenuation. In addition three blade props often have shorter blades reducing the tip speed lowering the internal and external noise level. But the alarms may have been sensitive mostly to the frequency which is proportional to the product of the blade count and the RPM and that product is likely higher on Dave's Bellanca than most of the other planes there. My Baron has 3 blade props (yet still makes a lot of noise) but since I only turn a bit more than 2600 RPM on takeoff the frequency of my noise is lower than Dave's.

 

[Ted]

Meanwhile, Pete thought that I didn't have the props full forward on my Aztec when I did my low pass. In fact, I had them (mostly) sync'd at rated RPM. Of course, for me rated is 2575 RPM. So, despite having only 2 blades, they're pretty quiet.

Just now catching up on everyone's compliments on my hair.