I have the taste of Metal in my mouth!!!

[speeddemon]

Re: I have the taste of Metal in my mouth!!!

Good stuff. Mike's right, I checked with my source inside hydro racing (a 4-time limited champ) who says that one of the Giffon Bud's big advantages was the near lock they had on some critical parts for 2 stage Giffons.

Most of the Bud stuff came from the Harrah's Club inventory during the late '60's. Bernie bought Bill Harrah's inventory out and sat on it for 10 years. Truth be told, the Harrah's guys really didn't know what they had, nor did they know how to exploit it. Harrah had gone out and just bought anything and everything they could find.

But the true secret for the Bud's success was the use of the PR-100 carburator. Trust me.

[TWD]

Re: I have the taste of Metal in my mouth!!!

And would the disadvantage of *any* prop turning the "wrong" way on a race course where all the turns are to the left be too big a factor to overcome? Yes, I know Centaurus Sea Furies have run well in the past, but it seems to me that the 3350 Sea Furies have run better than would be accounted for by horsepower alone.

Ok, someone school me as to why a Sea Fury would care if the race course went left vs. right.

[matt]

Re: I have the taste of Metal in my mouth!!!

well tj, the thought is that since the centaurus engine spins the "wrong" way, the prop would naturally have a tendency to try and pull it off course. however the 3350, and every other engine flown in the races spin clockwise (from pilots perspective) so they would, in theory, help keep the plane turning left.

[Unregistered]

Re: I have the taste of Metal in my mouth!!!

well tj, the thought is that since the centaurus engine spins the "wrong" way, the prop would naturally have a tendency to try and pull it off course. however the 3350, and every other engine flown in the races spin clockwise (from pilots perspective) so they would, in theory, help keep the plane turning left.

Howdy Matt,

Do you know the TJ is an accomplished pilot and has raced in the T-6 class? He might know, from his own experience and his dad's in Critical Mass - a Sea Fury.

Seriously - I think TJ was being sarcastic. There is no advantage or disadvantage to which direction an engine turns in reference to which way the course turns. The ball still has to be in the center.

Bill Meistien

[matt]

Re: I have the taste of Metal in my mouth!!!

bill, i know very well tj is a pilot.

it may have been sarcasm, but in all of the wonder that the internet is, it's still hard to express meaning. the way i saw it was that tj asked a question and i answered it in a way that everyone could understand. now, hearing from someone i don't know that the props direction of turn makes no difference isn't exactly a persuasive argument. but besides that it IS just a theory, not even an opinion.

[440_Magnum]

Re: I have the taste of Metal in my mouth!!!

Ok, someone school me as to why a Sea Fury would care if the race course went left vs. right.

Well, I'm the one really asking for the schoolin' here :-D

I've always assumed (and I could swear I've read it in an interview long long ago) that there is a small advantage in the fact that the prop torque rolls the aircraft the right (uh, make that 'correct') direction to bank into a left turn on a 3350 or Merlin or 4360-powered plane, whereas with a Centaurus or Griffon banking to the left requires banking against the prop's torque. Banking with the torque means that you can actually pull the alierons in out of the breeze (less drag) to initiate the roll, whereas you have to stick them out further than they already are to roll against the engine torque. Of course the opposite applies coming out of the turn, so maybe it really is a zero-sum game and doesn't matter.

I'm really asking whether its significant, not claiming that it definitely is significant.

[speeddemon]

Re: I have the taste of Metal in my mouth!!!

I'm really asking whether its significant, not claiming that it definitely is significant.

I don't believe that it is significant on the scope of what we see @ Reno. I think it may have made a difference on the old 'big' Mojave course during the 1000 mile races when they flew counter-clockwise. The Centaurus powered Sea Furies had an advantage then from the standpoint of pilot fatigue...but there aren't many people around who raced on both courses.

Ask Lyle. He has raced both ways in various types of airframes. Grima Myner too.

[Unregistered]

Re: I have the taste of Metal in my mouth!!!

at Mojave they turned right Shawn

[2101]

Re: I have the taste of Metal in my mouth!!!

It does make a bit of difference in that you are turning a gyroscope.A clockwise a/c turns better to the left as the force tends to lift the nose.Watch a cropduster and notice that the turn will almost always be to the left.

[TWD]

Re: I have the taste of Metal in my mouth!!!

The question was a serious one. It's thrown around by a lot of people that a centarus powered Sea Fury is at a disadvantage on the Reno course. I just can't figure out why that would be. I don't recall having flown an airplane yet that turned better one way than the other when it was up to speed.

The gyro forces of the prop is the only thing I can come up with.

Thinking back to when I got my flight instructor rating:

In a taildragger, when the tail comes up on take off, the nose swings left or right due to the gyro forces of the prop. I can't remember if it's 90 degrees ahead of the plane of the movement or the other way around. Went flying today, so I was gonna check it out on landing, but forgot and 3 pointed it.
Anyway, could this same force be exerted when the nose is tracking in a turn?

When it comes to rolling in and out of turns, it seems to me that if you enter and depart the race course wings level, then you've rolled left and right the same number of degrees. As was stated, Getting "help" rolling one direction would be cancelled out when rolling the other.

[Blue Foam]

Re: I have the taste of Metal in my mouth!!!

When it comes to rolling in and out of turns, it seems to me that if you enter and depart the race course wings level, then you've rolled left and right the same number of degrees. As was stated, Getting "help" rolling one direction would be cancelled out when rolling the other.

This is really the point. "Turning" on the course is coordinated. i.e. the dominant force is pitch, not roll or yaw.

The only net factor that torque plays on the course is in the case of engine out. On the Dart program we decided to run the power-on torque "into" the course (CW prop rotation), so that a roll trim force outboard would be required and an unexpected loss of power would result in an automatic rolling out from the course line.

[Chad Veich]

Re: I have the taste of Metal in my mouth!!!

It does make a bit of difference in that you are turning a gyroscope.A clockwise a/c turns better to the left as the force tends to lift the nose.Watch a cropduster and notice that the turn will almost always be to the left.

True, but the cropduster is maneuvering much closer to stall speed where gyroscopic effects are much more noticeable. (high throttle settings at reduced air speed)

[440_Magnum]

Re: I have the taste of Metal in my mouth!!!

Interesting discussion on prop rotation.

I had always assumed that any "disadvantage" to CCW was pretty small if it even existed, but given how hard it is to get every additional mile per hour at these levels, I've always wondered if it is something that would be considered.

[John]

Re: I have the taste of Metal in my mouth!!!

Is there a "cheap" way to thin it out?

Jarrod

Interesting that you would suggest this, as I remember looking closely at
Miss Ashley 2's prop blade tips and thinking 'those sure are thick sections.' Since the contra props were clipped it's easy to see why; as there is still a lot of structure there to support the cut off portions.

Miss Ashley 2 had a distinct sound, like buzzing, as it was coming at you, then you would hear the big Griffon. I personally think this "buzzing" was the interference of the contra set up -at the tips especially.

It seems they could modify the outer 10-20% propeller airfoils on PM to improve efficiency at high speed.

I do not know if this has been done already(?)

[Wild Bill Kelso]

Re: I have the taste of Metal in my mouth!!!

It seems they could modify the outer 10-20% propeller airfoils on PM to improve efficiency at high speed.

I do not know if this has been done already(?)

No it has not. They were just cut and filed. End of the tip is only rated for about mach.74. With the engine running at full pop the blades are going supersonic at the tip. About 4-5 inches of it. That is bad! We may loose some of that cool sound (or all of it), but hey I will take even 5 mph if it means a running engine on sunday night.