PM 38 Why the difference in prop length

[Wild Bill Kelso]

Re: PM 38 Why the difference in prop length

Ya, that could happen.

When monkeys fly out of your butt.

I'm going to make a monkey flying out of my butt costume for Halloween now.

[phoneguy]

Re: PM 38 Why the difference in prop length

Ya, that could happen.

When monkeys fly out of your butt.

Without the monkey weight...should make for a lighter wing loading and Precious Metal should be even faster.

Crow is best served "downhill in a tailwind", but before the Bear.

[RAD2LTR]

Re: PM 38 Why the difference in prop length

I already answered that. See last post.

Oops sorry, I didn't see your post. I had no idea those props were wooden. It sounds like those nosecases might be like finding a slow nose case for an R3350. I see where you are coming from though. A possibly risky proposition for sure. It also explains why it hasn't been done before. I wonder if it could be computer modeled and tested virtually to see if there would be any gains without having to find, buy, and try it. Who knows, there might be someone who would do it as a side project just for fun (pure speculation/wishful thinking there.)

Hey, with both Voodoo and Strega gone, the door is wide open. Sure, September Fury is fast, perhaps faster than RB simply because RB just doesn't seem to wish to cooperate with its keepers. It might be possible, it all depends on whether or not the bear wishes to cooperate. I honestly think PM has a shot if they can find a little more speed, and have luck go their way. At this point, the plane is faster than its ever been, and now flying in poorly charted territory. Sure, other P-51s have gone this fast, but the ones that have, haven't been using this specific formula.

All I can say is good luck, go fast, learn as you go.

Will

[Idaho_cowpony]

Re: PM 38 Why the difference in prop length

Ya, that could happen.

When monkeys fly out of your butt.

Actually...Assuming we don' t see Strega return, I'm counting up 4 2013 Unlimited's that have a very viable go at being faster than the Bear next year....

Joseph

[Tigercat24]

Re: PM 38 Why the difference in prop length

Actually...Assuming we don' t see Strega return, I'm counting up 4 2013 Unlimited's that have a very viable go at being faster than the Bear next year....

Joseph

So would those be PM, Furias (if rebuilt/repaired/re-whateverisneededforittocompete), 232, and the little Czech Mate?

[Wild Bill Kelso]

Re: PM 38 Why the difference in prop length

So would those be PM, Furias (if rebuilt/repaired/re-whateverisneededforittocompete), 232, and the little Czech Mate?

PM, Voodoo, 232, Smooter Scooter, Bear. Top five... Order unknown.

[Tigercat24]

Re: PM 38 Why the difference in prop length

Is this a hope that Voodoo will be raced again? (which I heartily share) Or is there some insider info???

[supercub]

Re: PM 38 Why the difference in prop length

Seems like I remember Tiger saying he was going to retire Strega from Air Racing in the past........like about 10 years ago or so..........seems like he said it for a couple of years.......but evidently he changed his mind..hopefully he will again.........sure would be nice to have Strega Voodo and all the others there for the 50th.
Brian

[Big_Jim]

Re: PM 38 Why the difference in prop length

Seems like I remember Tiger saying he was going to retire Strega from Air Racing in the past........like about 10 years ago or so..........seems like he said it for a couple of years.......but evidently he changed his mind..hopefully he will again.........sure would be nice to have Strega Voodo and all the others there for the 50th.
Brian

No, TIGER retired back in 2002 or 2003 because his eyesight was going bad. That was when Curt Brown was supposed to fly Strega but they had several 'issues' that precluded it. But Tiger had lasik surgery and was able to see enough to race again. And then he retired in 2008. I don't ever recall hearing the plane was going to retire.

[Blue Foam]

Re: PM 38 Why the difference in prop length

I'm not disagreeing that the airplanes speed and condition have been greatly improved. It's obvious that the crew has made great strives in the right direction. I'm not attacking the crew or the airplane, I simply disagree that you can make a direct comparison from this year to last. And I don't think that there is any solid numbers proving the new course is actually slower. Does anyone know what kind of power Strega ran last year during qualifying compared to this year?

I can tell you difinitively that the new course is 10 to 25 mph slower than the previous course at 500 mph. Why the large spread? The new course has far higher peak G and so aircraft with poor energy vs. G (read: bad wingtips) will suffer far more loss of speed on the new course.

We have excellent data on this from the jets. The ones with low energy loss vs. G fared far better than the ones with bad tips and high energy loss vs. G.

[wingman]

Re: PM 38 Why the difference in prop length

So Steve's qual speed in Strega would have been between 503 mph and 518 mph on last year's course??

And PM's qual would have been 473 to more than 485 mph?

[Cadet]

Re: PM 38 Why the difference in prop length

The nose cases and prop for the mk 74 Griffon are getting very rare and expensive. I would sure hate to convince our owners to spend the money and have it not work. Also if we had to cut the blades down for proper tip speed at race rpm I don't think you could because that is a wood core prop.

And I do want to know one thing. Could Cadet please tell us who you are and your background? I only ask because you opinions seem to lack what most the teams already know. The more constant and higher g's the airplane pulls the more it will bleed off speed. Therefore this course is slower. It's shorter so the speeds we saw in 2012 may not reflect average speeds too much because it's a shorter distance covered over time. We all set base settings for qualifying. I'm pretty sure they ran the same settings in 2012 as they did in 2011. During races they got out front and only used as much power as they needed to stay in front. That's how you run a good race program. PM did the same. We wanted to stay in front of Dread and only used enough power to do so.

I'm not a member of any team, maybe that's why my opinion is lacking. I prefer hearing some numbers or data before taking something for fact, not just one persons assumption. Thank you Bluefoam for taking the time to supply your findings on the new course. Do those numbers translate to the slower aircraft or are they not as effected because they are not getting as high G spikes?

[Idaho_cowpony]

Re: PM 38 Why the difference in prop length

Maybe I'll lean out and say 5 faster than Bear...if #86 can return..

But; I'll also post-script that, if a TC powering #77 is a built to race outfit for 2013...perhaps this could all change? Mr. Lewis; let's see her glory return!

Comparing the L-39's to our favored Unlimited class isn't really fair.

I would venture to say that overall the new course is better, but we need to at least see #2 move back toward the East. Any takers? Anyone who has flew the course want to comment?

Joseph

[wyhdah]

Re: PM 38 Why the difference in prop length

Great shot Neal, good luck Bill I love seeing PM and Thom competitive.

[Thom Richard]

Re: PM 38 Why the difference in prop length

Hi guys,

First off I'm flattered to have eight pages of discussion about something we did last summer. It's great to see the interest and the nice comments. Thank you.

Second, if you have any questions about PM or why we have done something to her, feel free to contact me. I'll be glad to explain it. Unlike the other teams that have things to hide (because they fly airplanes just like their competitors) I have an open door policy. Several reasons, we're the only team with a Griffon. It'll be a while before anyone brings another one in the mix, and more importantly, I want to live to race another day. What I mean by that is if I part with what I know and have experienced, others are more likely to share life saving information with me. For example, I am not a Mustang guy. I had no idea I was supposed to replace gear well springs every five years... Now I know. Many other pieces of advice have surfaced over the last eighteen months that we have implemented. I hope that continues. The people I lean on for engine advice are never given straight answers on power settings, which makes their work very difficult. I want the engine to live to race another day too... Engine development should not be WAG's and witchcraft, it needs to be based on real data. We needed a year like this one to collect enough information to know what we should do this year to improve what we have. You can't make twenty-seven uneducated changes and attribute a performance gain to any particular item. It's called R&D for a reason....

Now, the reason for the shorter prop? it's mostly been covered already. The design was my own brainchild and if it does not prove any faster than this it's my fault. It's a pretty long story which I'll tell at another point, but other than my (unproven) theory for the need to stay out of the front prop vortices, it's about being conservative. There was a resonance problem in the full length blades which is why the rear blades were cut on the Shack. I have no interest in researching that at 500+ mph. It's that simple. I'd love to do it in a wind tunnel some day.

Why not a single five blade? I can't afford to test it. I guarantee you our underdog rookie team has the smallest budget in the Unlimited Gold... Perhaps the entire class... Who else flies 5,000 miles on their race engine? We do it because we can't afford a second motor! Would a single screw be any better? Who knows? I don't think we ever will. The five blades are rare relics that belong on historic aircraft, not to be cut for racing. Justifying cutting a Shack prop is easy. No one uses them and they are being scrapped today as we speak because there is no need for them.

Is the new course faster or slower? That's a complicated answer and we really don't have enough data to suggest either one. It should probably be a separate thread. Strega did not go any faster and the rumors are similar power settings (and the weather was a little warmer, I believe) however, we don't know. The Sanders claim the Centaurus powered airplane went 10mph faster on the new course with no other changes. I could be that certain airplanes do better, at a certain speed range and G than others. We know the Bear for example does better on the straightaways etc, etc. my speed is not relevant due to the prop change, so I have nothing to add to the discussion. None of the other teams reported major changes to their airplanes this year, so they would be better at casting judgement. About the most accurate measure we have is, if this was Strega's last year and the competition was gonna be as tough as predicted, why did they not go for a 500+ qualifying record to go down in the books? Were they simply not able to go any faster on this course? If you want me to speculate, my uneducated wild guess would be that Strega was maxed out. But take that with a truck load of salt... In the end it really doesn't matter. We have to build for, and fly, the course provided. The qualifying record is for Reno, not the specific course design of a given year.

I think that's what you guys were looking for? I don't check the forum very often, but I'm easy to reach on FB or thom@race83.com

All the best,

Thom Richard