MA-II Speed Potential

[440_Magnum]

Re: MA-II Speed Potential

With all the Avro Shackeltons the Brits kicked to the curb, you'd think there would be a surplus of Griffons and contra-prop gear boxes. Where'd
they all go?

They're all single-stage Griffons, and thus not very amenable to being "hopped up." Except chemically (nice term, JS!), as was the plan for MA-II.

Also I've read several places that the contra-props have pretty crummy blade airfoils, so they aren't really the hot stuff you might think. Gotta remember- the Shackleton was basically a truck, not a hot rod.

[speeddemon]

Re: MA-II Speed Potential

Also I've read several places that the contra-props have pretty crummy blade airfoils, so they aren't really the hot stuff you might think. Gotta remember- the Shackleton was basically a truck, not a hot rod.

Exactly. They were made to loaf around at loiter-speed for hour after hour...not for sprint speed.

HOWEVER....the P-3 blades that were used on the Bear were also designed and utilized for exactly the same thing, and they found a way to make them go fast.

[Peashooter]

Re: MA-II Speed Potential

Exactly. They were made to loaf around at loiter-speed for hour after hour...not for sprint speed.

HOWEVER....the P-3 blades that were used on the Bear were also designed and utilized for exactly the same thing, and they found a way to make them go fast.

Mmmm, this is a job for Hartzell, Hoffman or MT -- new blades with a titanium shank and spar with a composite blade section... Not cheap, but very doable. Any former UDF guys out there?

[AAFO_WSagar]

Re: MA-II Speed Potential

They're all single-stage Griffons, and thus not very amenable to being "hopped up." Except chemically (nice term, JS!), as was the plan for MA-II.

Also I've read several places that the contra-props have pretty crummy blade airfoils, so they aren't really the hot stuff you might think. Gotta remember- the Shackleton was basically a truck, not a hot rod.

The GM big blocks are truck engines as well...

Bill Rogers told me an interesting thing about the -58 Griffon's that MAII was using...

When they talked with the Rolls engineers about them and what they planned on doing with them, the Rolls guys told them that of all the Rolls engines, they would be MOST comfortable with the -57/58 series being "hot rodded".

There is no question that the two speed blowers in the -57/58 were inferior to the two stage used in the -74...

But....

Is the reason that we never saw a single stage Griffon produce as much power as a Merlin in racing trim because you can't get it out of the single stage Griffon?

Or is it because the Merlin was the engine of choice and it was the one with nearly 40 years of tweek time to get it to the absolute limits of its power?

The prop/props was/were also a problem but... one has to wonder... if the right mods were done to the, readily available, Griffon off the "Shack" and the right prop combo was found... would we *maybe* have a really hardy engine that was available in relatively plentiful amounts?

MAII's engine was doing what it did with the simple addition of a, not fully tested to potential, N2O system. No massaging of the intake/exhaust system... nada..

One of MAII's engines was at Rick Shanholzer's, and he told me that he could do all the things to it that you'd do to a Merlin to get more power..

Obviously, that never happened but...

What if??

I'd still love to see someone make another Mustang work with a Griffon..

Here's a link to a story we did when Bill and Company were doing the N20 system.

Here's one that references just how hardy the Griffon is!

I truthfully didn't like talking about MAII for many years after the accident... It's finally been long enough to revisit some of the stuff we did on the airplane back then.. Doing a search on the site, we really did do a LOT of stuff on that airplane! It helps that I only live about 3.5 hrs from their base of operations!

The other thing that made it easy to cover their efforts... That crew "adopted" me at a time when I really needed to be adopted!

No question.. she was a beauty! They are a great bunch of people!

[MRussell]

Re: MA-II Speed Potential

Mmmm, this is a job for Hartzell, Hoffman or MT -- new blades with a titanium shank and spar with a composite blade section... Not cheap, but very doable. Any former UDF guys out there?

Ooo, just the thought of that gets me all excited and reminds me of Tsunami's scimitar (not to mention The Witch's partial scimitar).

[Bill Marsh]

Re: MA-II Speed Potential

Whether it is worth discussing..... just a overview request of info.

What are the similiaities or differences between MA-II and the PM aircraft


and , since im here typing a way.... what is the next level of "lessons learned" for a next gen A/C with a griffon


tossing out this big question

BMarsh

[speeddemon]

Re: MA-II Speed Potential

They both used the Shackelton gear/prop setup. They both used 'scratch-built' H-model tails. They both used 'basic' P-51D airframes...one 'real', one 'scratch-built'. They both used a stock P-51 tail wheel and retraction unit.

Beyond that, there really wasn't much in common at all. Different engines, different motor mounts, different wings, different cockpits, different just about everything else.

[440_Magnum]

Re: MA-II Speed Potential

The GM big blocks are truck engines as well...

MMMMFFFFF!!! That's the sound of a Mopar guy trying not to take the bait being waved under his nose ;-)

I'll be nice and just say that when GM put the Rat motor in a Chevelle, it had a lotta different parts than it had when it went in a C/K series And you don't really want an LS-6 cam in your tow truck, either

Bill Rogers told me an interesting thing about the -58 Griffon's that MAII was using...

When they talked with the Rolls engineers about them and what they planned on doing with them, the Rolls guys told them that of all the Rolls engines, they would be MOST comfortable with the -57/58 series being "hot rodded".

There is no question that the two speed blowers in the -57/58 were inferior to the two stage used in the -74...

But....

Is the reason that we never saw a single stage Griffon produce as much power as a Merlin in racing trim because you can't get it out of the single stage Griffon?

Or is it because the Merlin was the engine of choice and it was the one with nearly 40 years of tweek time to get it to the absolute limits of its power?

The prop/props was/were also a problem but... one has to wonder... if the right mods were done to the, readily available, Griffon off the "Shack" and the right prop combo was found... would we *maybe* have a really hardy engine that was available in relatively plentiful amounts?

MAII's engine was doing what it did with the simple addition of a, not fully tested to potential, N2O system. No massaging of the intake/exhaust system... nada..

One of MAII's engines was at Rick Shanholzer's, and he told me that he could do all the things to it that you'd do to a Merlin to get more power..

Obviously, that never happened but...

What if??

As John Slack pointed out, the nice thing about "chemical hot-rodding" is that you don't carry the size penalty of the big blower, AND you don't sap a lot of drive power back off the crankshaft to run the blower. It definitely has merit, if you can carry enough squeeze to run the race. And instead of spending all your time trying to shove in enough ADI for the amount of boost you're running, you get the advantage of the fact that the squeeze sprays in *COLD* and actually helps you out in terms of controlling induction temperatures and detonation.

The other thing that is rarely mentioned about the Griffon, but which I read in a Rolls-published book on the Merlin, is that it has a vastly simpler accessory drive system than the Merlin does. Not a huge advantage in racing necessarily, but simplification is always helpful.

One thing you obviously can't do with the Griff, though, is put in Allison connecting rods to make a beefier bottom end. In other words (wait for it....) you can't turn that Rat into a Mouse

[Peashooter]

Re: MA-II Speed Potential

The GM big blocks are truck engines as well...

Bill Rogers told me an interesting thing about the -58 Griffon's that MAII was using...

When they talked with the Rolls engineers about them and what they planned on doing with them, the Rolls guys told them that of all the Rolls engines, they would be MOST comfortable with the -57/58 series being "hot rodded".

There is no question that the two speed blowers in the -57/58 were inferior to the two stage used in the -74...

But....

Is the reason that we never saw a single stage Griffon produce as much power as a Merlin in racing trim because you can't get it out of the single stage Griffon?

Or is it because the Merlin was the engine of choice and it was the one with nearly 40 years of tweek time to get it to the absolute limits of its power?

The prop/props was/were also a problem but... one has to wonder... if the right mods were done to the, readily available, Griffon off the "Shack" and the right prop combo was found... would we *maybe* have a really hardy engine that was available in relatively plentiful amounts?

MAII's engine was doing what it did with the simple addition of a, not fully tested to potential, N2O system. No massaging of the intake/exhaust system... nada..

One of MAII's engines was at Rick Shanholzer's, and he told me that he could do all the things to it that you'd do to a Merlin to get more power..

Obviously, that never happened but...

What if??

I'd still love to see someone make another Mustang work with a Griffon..

Here's a link to a story we did when Bill and Company were doing the N20 system.

Here's one that references just how hardy the Griffon is!

I truthfully didn't like talking about MAII for many years after the accident... It's finally been long enough to revisit some of the stuff we did on the airplane back then.. Doing a search on the site, we really did do a LOT of stuff on that airplane! It helps that I only live about 3.5 hrs from their base of operations!

The other thing that made it easy to cover their efforts... That crew "adopted" me at a time when I really needed to be adopted!

No question.. she was a beauty! They are a great bunch of people!

GREAT post Wayne. Talk about a trip down memory lane! Wonderful stuff, and I love the bare-metal photo: http://aafo.com/racing/images/m2full.jpg

The stack-fire pic is a Cobra classic too, but I particularly like the t-hangar shot after all the pre-Reno '99 mods were completed.

[zeke]

Re: MA-II Speed Potential

They both used the Shackelton gear/prop setup. They both used 'scratch-built' H-model tails. They both used 'basic' P-51D airframes...one 'real', one 'scratch-built'. They both used a stock P-51 tail wheel and retraction unit.

Beyond that, there really wasn't much in common at all. Different engines, different motor mounts, different wings, different cockpits, different just about everything else.

How about the differences between MA11/PM and the Red Baron? Was she maore like a "noraml" P51 than the others. PM and the Red Baron deffiently look different to each other.

[Bottom Rudder]

Re: MA-II Speed Potential

One thing that was common amongst all three of the Griffon racers was that the counter rotating props had a tendency to make the planes 'hunt' or 'dutch-roll' when they had the normal size tail. Both the Red Baron and Precious Metal tried to run with the 'small' tails, and they had lots of longitudinal stability problems.

The reason that MAII had the H-tail wasn't the size of the rudder, rather it was the height of the stabilizer, getting it up into the clean airstream.

Tsk tsk tsk... Back to Aerodynamics for Naval Aviators, Obi-Wan...

Propellers are destabilizing. Add more prop area or another set of blades, and you're going to destabilize on both yaw and pitch axis. You don't have to stick it (the vertical) out of the prop wash, although that works. You have to, as you put it, increase vertical stab area.

That's a beer.

BM

[speeddemon]

Re: MA-II Speed Potential

Tsk tsk tsk... Back to Aerodynamics for Naval Aviators, Obi-Wan...

Propellers are destabilizing. Add more prop area or another set of blades, and you're going to destabilize on both yaw and pitch axis. You don't have to stick it (the vertical) out of the prop wash, although that works. You have to, as you put it, increase vertical stab area.

That's a beer.

BM

Okay, how about I clarify, using the Red Baron as an example. It is true that an increase in the vertical stab 'area' is what is required to stabilize in both the yaw and pitch axis. HOWEVER. The monumental 'oops' that Boland and Law made in the original design was to increase the chord on the RB's tail horizontally.

Shades of the Granville Brothers who felt that making the rudder chord 'longer' would make the R-1 more stable without the 'drag' of a 'taller' tail.

Only it didn't work. At Mojave in '75, Mac was all over the place. And the barn door they slapped on the ventral on Sunday of race morning was barely enough to keep the nose pointed in the right direction. What they needed to do was extend the tail upwards 18 inches--INTO CLEAN AIR so that the stabilizer could do what it was supposed to do.

And when they did that for Reno '75, they actually ended up with overkill...a tail that was tall enough to do the job, but with a chord that I would guess actually hindered the turning characteristics of the plane around the course. TOO MUCH tail.

But I'll still buy you that beer.....but only because I'm thirsty.

[Mluvara]

Re: MA-II Speed Potential

Only it didn't work. At Mojave in '75, Mac was all over the place. And the barn door they slapped on the ventral on Sunday of race morning was barely enough to keep the nose pointed in the right direction. What they needed to do was extend the tail upwards 18 inches--INTO CLEAN AIR so that the stabilizer could do what it was supposed to do.

And when they did that for Reno '75, they actually ended up with overkill...a tail that was tall enough to do the job, but with a chord that I would guess actually hindered the turning characteristics of the plane around the course. TOO MUCH tail.

It generally takes more tail area forward to equate to a smaller amount further back, since it relates to a volume coefficient. So, adding it on top vs a ventral fin generally does more. But, that's not to say that getting it out of the prop isn't necessarily a bad thing.

My understanding is that the Red Baron was extremely tail heavy early on. Adding tail area can help this some, but not completely solve it. I think it was said Greenamyer got in it and asked if they were trying to kill him after he got it back on the ground... because it was tail heavy.

Michael

[Bottom Rudder]

Re: MA-II Speed Potential

Obi-Wan,

You are missing a central fact to that year with the Red Baron... It was massively tail heavy. That had, probably, a lot more to do with it.

As you well know, aft cg negatively effects all forms of stability.

Boland's adding the ventral fin was a good try, but I would think the air under there is kinda like a moody woman.

After you buy me that beer, I'll buy you one...

BM

[speeddemon]

Re: MA-II Speed Potential

I think it was said Greenamyer got in it and asked if they were trying to kill him after he got it back on the ground... because it was tail heavy.

Michael

Yes, the 'sanitized' version of this story was in Gandt's book "Fly Low, Fly Fast". A close friend of mine, however, was standing within earshot of the plane after it landed, and Darryl grabbed Randy Scoville by the scruff of the neck while still sitting in the cockpit and cut loose with a much more 'colorful' version. :-)

But that incident was about 'assumptions'. Darryl was used to taking the Bearcat off in 3-point configuration so as not to scrape the prop. Mac, on the other hand always knew that the RB was tail heavy and made 'normal' tail-up take-off's...because if you took off in a 3-point configuration, the wing would wash out the elevator control.

The fact that the RB was tail heavy didn't 'cause' Darryl's problem. The plane will take off and land just fine being tail heavy...provided you know about it.

Nobody told Darryl about it because nobody thought he'd try to take off that way.

Classic example of 'failure to communicate'.