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Handling and the "iso fulcrum" approach...


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#1 strummer

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Posted 22 March 2020 - 11:13 AM

So as I stated on Matt's thread about the Cucaracha", I'm still not 100% clear as to the advantage of the "IFC" over the standard drop arm, as they seem to do (more or less) the same thing. Perhaps you all can illuminate one such as myself. :)

 

I didn't really get the idea behind the "drop arm" thing at first, but with this feature on my first two 1/24 cars, I have come to really appreciate it and its advantages. So...

 

...since my latest addition (the Revell Lotus 23) does not have this, I was hoping I could add a drop arm and still leave the chassis stock. But no such luck. I happen to have drop arms of (2) different lengths, but neither will work in this situation without having to seriously modify the original chassis; basically, the "tab" that holds the existing pick-up shoe would have to be removed, so unless I can score a replacement front chassis section, I guess I'll learn to live without it for the time being.

 

"Weight" is often mentioned in discussing handling improvements: anyone here care to share their thoughts and perhaps a photo or two...?

 

Mark in Oregon

 

 


Mark Mugnai




#2 Pablo

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Posted 22 March 2020 - 03:46 PM

The main advantage of an ISO design is, the weight of the entire center section, including motor, adds weighting to the flag. A simple drop arm only puts the weight of the arm itself onto the flag. An ISO pan assmbly/front wheels are free to wiggle, tilt, lift and react to track irregularities without disturbing the entire car. Done right, the ISO design works superb.

 

post-91-0-35527800-1552428935.jpg


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Paul Wolcott

#3 Martin

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Posted 22 March 2020 - 04:26 PM

As I stated in post #5 in Matts Cuc post.

"One more thing to note, the guide shoe and the motor are on the same part of the chassis".

 

And Paul restated above "The main advantage of an ISO design is, the weight of the entire center section, including motor, adds weighting to the flag."

Very nice Iso chassis Paul :good:

 

Bottom line  though is does not work any better or all modern chassis would adopt it. Like I said before when I race in the Cuc class we tape the 2 parts of the chassis so they were rigid. Wheels  .010" off the ground. Now you have maximum weight on the guide.

Add lead and test.     


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Martin Windmill

#4 Pablo

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Posted 22 March 2020 - 04:35 PM

Thanks Martin. Mark I know your question is basically about production cars, so here is another Pablo car you may get some info from. A stock Cuc refurb that I tried to basically keep stock but blueprint everything so the chassis performed as the designers intended it.

 

It performs worlds better that a stock Cuc because every thing is just "right".


Paul Wolcott

#5 strummer

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Posted 22 March 2020 - 06:05 PM

As I stated in post #5 in Matts Cuc post.

"One more thing to note, the guide shoe and the motor are on the same part of the chassis".

 

And Paul restated above "The main advantage of an ISO design is, the weight of the entire center section, including motor, adds weighting to the flag."    

 

Okay; there it is.

 

That and the bit about "A simple drop arm only puts the weight of the arm itself onto the flag".

 

Now I get it. 

 

Thanks guys.   :)

 

Mark in Oregon


Mark Mugnai

#6 MattD

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Posted 22 March 2020 - 06:12 PM

over the past 40 years engineering types have found out the drop arm is  not really a great design.    It was great to see a LRW do a wheelie, but on a decently smooth track it is a waste of energy and better to be in a fixed position.    Study the designs and a simple drop arm like a Cox mag chassis and an iso design are actually very different approaches.   


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Matt Bishop

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#7 strummer

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Posted 22 March 2020 - 07:13 PM

over the past 40 years engineering types have found out the drop arm is  not really a great design.    It was great to see a LRW do a wheelie, but on a decently smooth track it is a waste of energy and better to be in a fixed position.    Study the designs and a simple drop arm like a Cox mag chassis and an iso design are actually very different approaches. 

 

Yes, I can see that now; thanks to you and everyone who chimed in.

 

I suppose the only "real" advantage of the drop arm is when re-slotting (is that the correct term?); you can see what you're doing better!  :)

 

Mark in Oregon


Mark Mugnai

#8 old & gray

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Posted 22 March 2020 - 09:30 PM

Mark you need to remember the changes in chassis are following a moving target.

 

The drop arm design was an era when there were humps in tracks which would send a car airborne. The drop arm would keep the guide in the slot until the car came back down. Look up pictures of the front straight on the American 150 Red or bridges on Revell tracks.


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