bret
Well Known Member
Check out sky dynamics new cylinder girdle. http://www.skydynamics.com/frame.htm They claim to have fixed the cracked baffle problem, and engine flexing by tying the cylinders together. interesting product!
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Do you have a girdle?
- Thread starter bret
- Start date
They also claim increased horsepower, which causes my BS meter to twitch more than just a little bit. It's gonna take a lot of engineering drawings and equations to convince me you are going to get any more power out of that arrangement.
"These girdles substantially limit the cylinder's natural X-Y movement to increase durability and horsepower in high power applications."
Goin' Girdle
I think their argument is like stud girdles on high HP automotive applications, the girdle doesn't MAKE horsepower, it ALLOWS more horsepower to be made without shortening the life of the engine.
They might want to work on their wording there.
Valvetrain stud girdles are well proven in V-8s, not so sure that directly applies to "cylinder" girdles on a Lycosaurus however. But, ever forward with innovation.
Here are the ones I run on my small block TPI chevy 383, 10.5 to 1 compression.
http://www.jegs.com/p/AFR-Airflow-Research/AFR-Stud-Girdles/820890/10002/-1
I think their argument is like stud girdles on high HP automotive applications, the girdle doesn't MAKE horsepower, it ALLOWS more horsepower to be made without shortening the life of the engine.
They might want to work on their wording there.
Valvetrain stud girdles are well proven in V-8s, not so sure that directly applies to "cylinder" girdles on a Lycosaurus however. But, ever forward with innovation.
Here are the ones I run on my small block TPI chevy 383, 10.5 to 1 compression.
http://www.jegs.com/p/AFR-Airflow-Research/AFR-Stud-Girdles/820890/10002/-1
ColoRv
Well Known Member
I tried pretty hard to buy one of their maxi sumps at one point. Never had any luck and when I spoke to the owner his answer for when they would be available was something like 'when we find a foundry that will make them for us'. A couple months later, still no joy so I went with Superior for far less money. I can find a foundry to make me a lifelike rendition of a pile of dog poo made in magnesium in about a week. Something is off when a client is standing with a fist full of money and you cant sell them your flagship product in two months. I hope they got it together, but in short...if its not in stock..don't hold your breath.
LifeofReiley
Well Known Member
Just what I was thinking. Anytime you constrain motion that has worked for a couple of million hours, you are going to transfer that stress somewhere....
I'm just spitballin', but try this theory.
The port cylinders bend a wee bit downward and the starboard cylinders bend upward, both in reaction to piston side load during the optimum crank angle portion of the power stroke . Side loading gets worse as combustion gas pressure is increased, or (generally) as stroke is increased. The bending cylinder can be modeled as a spring. Most of the available energy goes into pushing the connecting rod and some goes into compressing the spring. Of course the spring stores the energy and returns nearly all of it when the opposing pressure is released, but by then it's too late to result in crankshaft torque.
And yet, a large diameter cylinder would be quite stiff in torsion, and if the cylinder were monolithic, rather than a two-piece screwed head and barrel assembly, it might withstand the forces pretty well.
You know, cylinders like the ACE AX50 cylinders on Kevin's test mule:
On the other hand, if one borrowed the idea without considering the screw joint, life may be compromised. Unacceptable to most, but if your customers are performance types who clearly don't mind some loss of engine life in return for HP....
This is getting pretty common on big horsepower engines. It seems to make sense in my book, and I'm tempted to make some of my own.
Like on this supercharged 780:
Or this Turbo Charged 720:
Big compression loads divided over more than 1 head, that is all I need to know about it.
Like on this supercharged 780:
Or this Turbo Charged 720:
Big compression loads divided over more than 1 head, that is all I need to know about it.
Bob Kuykendall
Well Known Member
I'm also pretty nervous about stuff like this executed by folks without access to the original engineering data. These days I see a lot of parts made with CNC and 3D printing that look very pretty, but demonstrate a distinct absence of engineering wisdom.
Thanks, Bob K.
Re the 780 "girdle". If I assume the aluminum girdle is 24" from the inside point of the end heads, the expansion with just 100 degrees F change in temp is .0295". That means that it is trying to separate the end heads that about far. If you assume a 0 deg F to 200 degree operating range that is .061" of movement. Seems like a lot of preload stress to the end cylinders to me, even for just a 100 degree change. But maybe the vibratory loads are much higher. Interesting. Love to see a FEA on the engine.
Good point, but the cylinder bases move apart too...the case has a similar thermal expansion.
rbibb
Well Known Member
I'm sitting about 5 miles from their location and am tempted to drive over in the morning and take a look?
As far as producing hp - sure these things don't do that. But it take a fair amount of energy to move those cylinders around. If you can stop some of the energy produced by combustion from being wasted bending the cylinder back and forth that energy can then be used to turn the crank. I believe that to be the basis for the claim. Their instrumentation readouts seem to show some significant improvement in reducing that movement. Now how much hp that equates to would take some math work and access to the data that I"m not even going to attempt right now.
My beer would just get warm and that would be waste of another valuable energy resource?.
As far as producing hp - sure these things don't do that. But it take a fair amount of energy to move those cylinders around. If you can stop some of the energy produced by combustion from being wasted bending the cylinder back and forth that energy can then be used to turn the crank. I believe that to be the basis for the claim. Their instrumentation readouts seem to show some significant improvement in reducing that movement. Now how much hp that equates to would take some math work and access to the data that I"m not even going to attempt right now.
My beer would just get warm and that would be waste of another valuable energy resource?.
LifeofReiley
Well Known Member
I've got ocean front property in Arizona if anyone is interested... 
Toobuilder
Well Known Member
A bit off topic, but along the lines of "controversy" - anyone notice the NXT pictured has header wrap installed on the exhaust and intake?
rocketbob
Well Known Member
I was once told that a spotlight facing up was placed under a Continental 550 in a test cell. A grid was placed on the ceiling and it was determined that the cylinder tops were moving 1/16".
I'll have to get working on a set of my own.
It also appears that a set of GM coils were used in place of the small coils used with the LSE ignition system.
I'll have to get working on a set of my own.
It also appears that a set of GM coils were used in place of the small coils used with the LSE ignition system.
Gents,
OLD topic, but still very interesting product.
For me its more natural this removes stress and therefore increase life on case. However the free energy will properly move to the intended place ?
As someone is talking about other place in the topic.
But this is an old thread and wounder about any have harvested any experience ?
Best regards
Lancairbuilder
