Inline Horses or Wright Roundies?

[Apteryx]

Re: Inline Horses or Wright Roundies?

There have been 31 wins of radials over the years since 1964.

41 wins with V-12's, of which 6 were Griffons.

Allison's have never had a win. (Come on JC, this is your job!)

...or Murdo Cameron....

[MIKE NIXON]

Re: Inline Horses or Wright Roundies?

Wow, this is funny>
I was thinking of using 12 pistons in Strega this year just to keep it interesting.
Someone famous once said "I have just begun to fight". Hint: Navy man.
We never stop looking for more thrust in Strega.
#5 It will be a good race between 7 and 5. Steveo is a real leader in this.
Matt has the talent and expeerience to match and this will be gamesmanship 401.
PM Hats off to Thom for getting the plane into the top 5. However I been there, dun that. We have too many limits in this sport to take advantage of the Griffons CID. In the boats, they were unbeatable. However refer to the quote above. There is a lot left in that A/C engine combo and that team is digging deep to find it.
lets see did I forget anyone? Round engines!
In lines win the drag race and the round engines can take the endurance race.
Place your bets and no crying Sunday eve.

[MIKE NIXON]

Re: Inline Horses or Wright Roundies?

Thom
I assume you are including other races. I get 72 total
MN

[Exhaustgases]

Re: Inline Horses or Wright Roundies?

I maybe wrong, but from what I have gathered about the airplane race engine topic is, the racing mods to the engines is very limited. Ever since I was a kid (teenager) I had some engine mod ideas that I was surprised that no one seemed to be using. Including hydroplane racers, I would have loved to get to work on a race boat team then. There is so much room for improvement in the engine department on race planes, especially the radials.

[V1670]

Re: Inline Horses or Wright Roundies?

Allison's have never had a win. (Come on JC, this is your job!)

Do you mean Gold heats? Didn't Levitz win a bronze in his P-38 way back when? My memory is.........what was I sa....?

[Thom Richard]

Re: Inline Horses or Wright Roundies?

Thom
I assume you are including other races. I get 72 total
MN

Yes, all 72 Sunday Gold races at all venues. All information courtesy of The great Pete Law.

[JCP]

Re: Inline Horses or Wright Roundies?

There have been 31 wins of radials over the years since 1964.

41 wins with V-12's, of which 6 were Griffons.

Allison's have never had a win. (Come on JC, this is your job!)

Hold on to your hat Thom... I won Saturday's Bronze Heat Race in the "Parrothead" to move me into the Sunday Silver back in 2009! (where I then predictably got my A*$ handed to me)

That was the first and only race ever won by a P-40! I'm certain Fred Sebby was smiling.

JC

[3350nut]

Re: Inline Horses or Wright Roundies?

I maybe wrong, but from what I have gathered about the airplane race engine topic is, the racing mods to the engines is very limited. Ever since I was a kid (teenager) I had some engine mod ideas that I was surprised that no one seemed to be using. Including hydroplane racers, I would have loved to get to work on a race boat team then. There is so much room for improvement in the engine department on race planes, especially the radials.

You are correct . I am of the same opinion as in room for improvement in the radial engine (some are being accomplished as we speak)it has always been my opinion that it is much easier to make a aircraft with the frontal area of a bullet go 500 MPH than one with the frontal area of a brick. so if you can make a brick go 500 MPH you have really accomplished something , AND I REALLY LIKE BRICKS (just my opinion) see you in reno

[Warbirds45]

Re: Inline Horses or Wright Roundies?

I have a question. Although the aircraft is shape like a bullet, and the radials have a blunt aspect. What about the propeller itself? Does it not cause some friction? It is creating a larger surface to pull the aircraft thru the air. Does the propeller even factor in?

[N22252]

Re: Inline Horses or Wright Roundies?

I have a question. Although the aircraft is shape like a bullet, and the radials have a blunt aspect. What about the propeller itself? Does it not cause some friction? It is creating a larger surface to pull the aircraft thru the air. Does the propeller even factor in?

It definately does... The last flight of the Red Baron RB-51 would be the example of the bullet suddenly becoming a brick due to drag from the propeller disk.

[Big_Jim]

Re: Inline Horses or Wright Roundies?

It definately does... The last flight of the Red Baron RB-51 would be the example of the bullet suddenly becoming a brick due to drag from the propeller disk.

But that question had to do with the comment on the previous page about the contra-rotating props being 'more drag'....and the real answer is, they're not. As far as frontal area, they leave the same footprint, since the rear one is in the front one's shadow. The rear one recovers the spilled air from the front set and extracts 'extra' efficiency out of it as well as straightening the airflow over the airframe...theoretically a reduction in drag right there.

I think the term 'drag' was mis-used instead of 'efficiency'. If you're spinning the prop faster than it should be going for the given length vs. rpm, the 'wing' of the prop loses lift and therefore becomes less efficient.

Almost 40 years ago when the RB-51 team utilized the Shackelton prop they cut the length down to what they thought (based on Boland's calculations for Zeuschel's horsepower/rpm predictions) would match the power range they would be running in. When Whittington did his version, he cut the blades 'wrong' (for lack of a better term) for the rpm that he thought they might be running at some destruct-power. Jeff Neff told me that they pretty much guessed on that too.

Both of those were somewhat inefficient and got increasingly so as the power and speed increased. What Thom has done on PM has been calculated at a realistic rpm/power setting with a new set of blades that are longer, but cut much more efficiently. So it's just a better shaped 'airfoil' up front. I'd hazard a guess that it is the most efficient prop in use by the Unlimited Class at the moment, so it's getting 'more' lift/pull/thrust at the same power settings than the old blades.

The 'drag' from the RB-51 incident was just a result of the prop governing system being operated outside of it's range, so when it lost oil pressure the blades went to flat pitch. Jeannie almost stopped in mid air in about 10 seconds in '82 when it had a prop overspeed for the same reason. 'Drag' during a mechanical failure doesn't equate to 'drag' because of two props when operating up front. That was what "I" was questioning about the statement.

[Thom Richard]

Re: Inline Horses or Wright Roundies?

What Thom has done on PM has been calculated at a realistic rpm/power setting with a new set of blades that are longer, but cut much more efficiently. So it's just a better shaped 'airfoil' up front. I'd hazard a guess that it is the most efficient prop in use by the Unlimited Class at the moment, so it's getting 'more' lift/pull/thrust at the same power settings than the old blades.

Thanks for that, Big_Jim! It took a lot of backyard mechanizing, voodoo and black magic to make them perform. I personally believe in the concept. Otherwise I would not be investing what I am in the project.

There are two completely different schools of thought on the contra-rotating installation, one camp "feels" that the induced drag of six blades is detrimental to performance. I, on the other hand believe there is speed to be had by not having any left turning tendencies to compensate for in the airframe. There is very little wind tunnel research on this subject that I am aware of. Perhaps someone can dig some up?

You are right about the power setting. We used (according to Jeff Neff) a power setting that was 800RPM less than that of Don Whittington's when he turned 453mph. That's a pretty significant number for a big V-12... Unlike the other race Mustangs, I am not yet a member of the 100" club. The current power-plant can do it, but the oil would overheat very quickly. Which would not allow us to complete a heat. Hopefully our overhaul this year will solve all the "old engine" issues.

Now, will the "Mix-master" run in to an imaginary "wall of drag" in the upper 400's? Who knows? But I trust you will all be there when we try in September...

On the Inline's vs. Roundies argument, there is obviously no replacement for displacement and lack of drag. What we need is a 4,360 cu in V-16!

[Idaho_cowpony]

Re: Inline Horses or Wright Roundies?

I have personally always loved and dueled over the Griffon/Stang combination. It's going to be so satisfactory to see what 'Metal' is really capable of, and September cannot come fast enough!

I stand my my earlier comment.....505 laps, I believe are well within reason.

And Thom, your line last year really looked good too. Looked like you are very comfortable with the airplane, and that's got to be a big part of a winning combo.


- Joseph

[WARPT]

Re: Inline Horses or Wright Roundies?

Hold on to your hat Thom... I won Saturday's Bronze Heat Race in the "Parrothead" to move me into the Sunday Silver back in 2009! (where I then predictably got my A*$ handed to me)

That was the first and only race ever won by a P-40! I'm certain Fred Sebby was smiling.

JC

I thoroughly enjoyed that race! To see that P-40N leading a Mustang, a Corsair and if my memory serves me right a Sea Fury too was an absolute treat!

[supercub]

Re: Inline Horses or Wright Roundies?

How bout a V-24 3420

Brian