THE BEAST!

[dwilfong]

Just give it time !!

View attachment 98511

Thats not a bearing now is it!!!!!!!!!!!!!!!!

 

[brad nichols]

If it was gold it would be OK

Brad

 

[Tom Foley]

Thats not a bearing now is it!!!!!!!!!!!!!!!!

The aftermath !!

 

[charles siler]

Just give it time !!

View attachment 98511

Looks like Giblets to me hey is that a faulty needle bearing lol

 

[mark ham]

there is a lot more going on there than just a bad bearing.

 

[dwilfong]

well when you pull the wrist pin out of the lower unit ex you know you have done something......LOL

 

[LohringMiller]

That looks a lot better than a Quickdraw we seized at 20,000 rpm.  I don't think there were any reusable parts.  It was a good dyno stress test.

Lohring Miller

 

[Tom Foley]

That looks a lot better than a Quickdraw we seized at 20,000 rpm.  I don't think there were any reusable parts.  It was a good dyno stress test.

Lohring Miller

we have plenty more . Any pics of that Quickdraw ?

 

[LohringMiller]

Mike has the pictures.  I think he was embarrassed and didn't want them seen.  The only other incidents we had were burned pistons on nitro engines and a burned plug from 40% nitro in a Quickdraw.

Lohring Miller

 

[Terry Keeley]

That looks a lot better than a Quickdraw we seized at 20,000 rpm.  I don't think there were any reusable parts.  It was a good dyno stress test.

Lohring Miller

Just curious, did you have a one-way bearing or clutch on that dyno?

What happened when the motor seized?

ps:  I'm in the design phase...

 

[LohringMiller]

We only ran a centrifugal clutch with a square key connecting the engine to the flywheel.  The key twisted almost 180 degrees before the clutch released.  The flywheel inertia probably contributed to the destruction by revolving the crankshaft after the piston seized.  It takes a serious one way clutch to handle the input.  I might include one like this  in a new build but the key plus clutch combination did work.

Lohring Miller 

 

[Terry Keeley]

Cool.  I'm gonna use a one-way bearing plus one of Dave Marles steel shoed clutches:

http://www.prestwich.ndirect.co.uk/gasengineaccesories.htm

https://www.vxb.com/CSK15PP-One-way-p/kit10968.htm

That's a serious stand you have it on!

 

[Terry Keeley]

duplicate...

 

[LohringMiller]

I worry about your one way clutch.  The kart dynos use positive engagement types like I pictured.

Lohring Miller

 

[Terry Keeley]

I worry about your one way clutch.  The kart dynos use positive engagement types like I pictured.

Lohring Miller

Why?  

I have a buddy (Mike Ross - Suicidal Engines) that runs one.

If the motor stops suddenly (as in your case) the inertia wheel just keeps motoring - instant disengagement. 

I was thinking of incorporating it right in the clutch's outer housing, that way the shaft and all can freewheel if needed. 

 

[dwilfong]

There was a Dyno that used a belt to drive the wheel. 

Think it was some one from Sweden if I remember correct tuning RS .91's

The bearing on the wheel shaft for the pulley was a clutch bearing.

The wheel could run at half speed then.

Would also not drag  the eng on deceleration.

 

[Terry Keeley]

Would also not drag  the eng on deceleration.

Another bonus.  Not good to shut the throttle and have the wheel still pulling the motor along at 25K!

Here's a bunch of home made interia dynos: http://performancetrends.com/CustomerDynos.htm

I'm gonna go direct drive to minimize losses, wheel should be about 4" diameter and 6" long to absorb the 5 hp and 27K from 67-90's.  I'll turn shafts into the ends of the wheel in one piece between centers.

It'll probably look like one of Dave Marle's older dynos...

 

[Ken Retallick]

I built a dyno many years ago similar in design to the one in Terrys pic.

I made a multi plate clutch to connect the engine to the load wheel.  Operated with a lever right next to the throttle lever.

Operation was start engine, Either a Zenoah or Nitro, release clutch slowly to get the flywheel spinning, open throttle to get the pull then shut throttle and disengage clutch at the same time.

Only issues i had were twisting 1/4 inch keyways from engine to clutch into rather fancy looking threads.  Later solved by using square flex shaft.

 

[Terry Keeley]

I built a dyno many years ago similar in design to the one in Terrys pic.

I made a multi plate clutch to connect the engine to the load wheel.  Operated with a lever right next to the throttle lever.

Operation was start engine, Either a Zenoah or Nitro, release clutch slowly to get the flywheel spinning, open throttle to get the pull then shut throttle and disengage clutch at the same time.

Only issues i had were twisting 1/4 inch keyways from engine to clutch into rather fancy looking threads.  Later solved by using square flex shaft.

Got any photos of it?

 

[LohringMiller]

Your setup is a very compact unit.  The dyno you pictured looks like Dave Marles' dyno.  People I've talked to have twisted 1/4" cable connectors, broken belts and destroyed Octura pin couplings.  Prop loads are much kinder than the dyno flywheel.  Try that style of one way clutch and see how it does.  Single cylinder engines pound the couplings.  I was very cautious with over engineering our dyno, especially the flywheel.  The Lovejoy coupling also wasn't needed.  We destroyed a softer rubber element before we switched to the hardest one.  The key into Aeromarine square collets also had a limited life.  The keys and square collets are cheap, though.

Lohring Miller