92 replies to this topic

[gotboostedvr6]

Pin the forward most portion of the blade.

[mark1]

Don't solder the wires on the clips while they are in the guide. Make a fixture for that, or use an old guide. Nylon RC airplane propellers required boiling. The instructions that came with the prop said so. I always boiled them. Never had a piece of the prop hit me in the face at 12,000 rpm. Now props are made of a different material.

[mgerbetz]

I dont know much about the science of plasics, but just curious about the materials being used;

Why are the current materials being used ?
Does it make sense to try something different ?

https://www.osbornei...stant-plastics/

[Eddie Fleming]

Not sure we are helping Mike much with his original request, but I have a question for the engineering types.

 

Is impact resistance the proper property to be looking for with this type damage? 

[brucefl]

I say discombobulated the discombabular,and your problem is solved,good luck.

[brucefl]

Coat it with that liquid rubber,problem solved.

[Dave Crevie]

The samples do seem to show impact damage. What I find interesting is that only the top of the braid area is damaged. If it

was caused by hitting a wall, I would expect that the entire corner would be damaged, top and bottom. I tend to believe that

the damage is from the guild going under a chassis as it runs into the rear, or side, of a car. 

[Half Fast]

I say discombobulated the discombabular,and your problem is solved,good luck.

 

Some opinions are needed, some opinions are not needed.  

 

Cheers

[MSwiss]

With my guys gathering for Saturday night racing, I got a few pinned guides to go with the graphite one that broke.
 
Note, one with right side damage is included
 
In the case of the yellow one on the right, Bernard said the clip bent up and was scraping against the body.
 
He said once he pushed down the clip, everything was fine.
 
IOW, it held the braid in fine.

So it's essentially what I did in the first post.

Just a little deeper back, and not even.

[brucefl]

Solution,either manufacture a super guide that incorporates a more durable material or a more durable design like strength ribbing ,or the racer should coat the guide with epoxy or suitable reinforced material to add needed strength or build a cage to cover it,or just replace guides as needed,if its reoccurring too often then determine when that happens what the variables are,in those situations to determine if its driver related track related or lane related,or guide has a life expectancy issue and hasnt been replaced at correct interval.

 

now this may all sound obvious or ill informed on my part but,maybe even a dunce can have a good thought from time to time.

[brucefl]

do like a dentist does find a material to coat the guide that will show you where the excess wear or friction is,that may help you,you could either go section by section unless you know where the track issue is,where the material is gone thats the excess pressure area,you can use maybe lipstick,paint in on and see,repeat over and over.

[Bucky]

I've always used guide clips, but do the guys that just use the lead wire slots have the same issue breaking the braid box? Would adding a softer material into the arc of the guide clip between the clip and the guide help absorb the types of impacts that break the braid box?

[Ecurie Martini]

Disclaimer:  Little experience with this style guide and none with cars big/heavy/fast enough to incur this type of damage due to collision.  That said, looking at the "data" two things come to mind:  First I would look at the mold flow diagrams for what I presume are multi cavity molds used to produce the parts to see if there is any R/L difference in flow patterns, fill time or mold cooling.  The second thought that occurs, and this is based solely on my recollection of a Blue King track - LH turns predominate and, if there is any significant "lifting" of the guide it might induce some arcing and heating of the braid with concomitant softening of the adjacent plastic part. My $0.02

 

EM

[Dave Crevie]

The parts are molded in hot runner molds. There are no sprues. So every part should be identical, if the cooling lines to each cavity

are the same. That could only be determined through thermal analysis, and at the manufactured price of these parts, no one is going

to bother with that. Looking at the graphite guides I have, where I can see the flow lines, there doesn't appear to be any difference from

cavity number to cavity number. And the vestage from the inlet is on the nose of the guide, close to the braid openings. So it is unlikely

that the temp is lower there. Unless the nylon was too cold to begin with. 

 

The problem is evident in guides of various materials, so I am sure the damage is impact related, and not from inferior material. 

[MSwiss]

I was PM'ed by a top racer, who runs half clips, and solders his wire to it, in that slot, and he said he still has the braid pocket split on occasion.

I think the front wraparound of the clip is important, to help take the hit.

 

 

I've always used guide clips, but do the guys that just use the lead wire slots have the same issue breaking the braid box? Would adding a softer material into the arc of the guide clip between the clip and the guide help absorb the types of impacts that break the braid box?

Yes. See above quote. It was post #12.

 

I thought of a sponge material inside the front curve of the clip, but it would push that curve forward for less clearance.

 

Hence my idea of just cutting away some material to let the back of the pocket to absorb the impact with the clip.

 

I don't see that material providing much added retention, especially if you glue the clip into place.

[JimF]

After thinking about this (dangerous.....that thinking thing) seems like the few peels that I've experienced have mostly been on retro stock cars (one F-1 that I can think of). Those big heavy stockers are obviously going to make the guide more vulnerable. Seems to me that the very simple and previously mentioned trimming back of the top chord of the pocket might mitigate the potential for damage. At the very least, it's simple enough and I can't think of a negative so.....prolly worth a try on a couple of 'em.

[Dave Crevie]

OK. How many of you are old enough to remember the old Eurotoy stamped steel chassis? They had a loop that went around

the front of the guide shoe. Has anyone tried doing that, and did it eliminate the problem? We put gear guards on retro chassis, 

might be something to try. 

[Eddie Fleming]

OK. How many of you are old enough to remember the old Eurotoy stamped steel chassis? They had a loop that went around

the front of the guide shoe. Has anyone tried doing that, and did it eliminate the problem? We put gear guards on retro chassis, 

might be something to try. 

Bryan Warmack

 

Ask him. I ask earlier but suspect he is very busy this weekend.

[mreibman]

After a pretty dismal race on Saturday, I elected to replace my chassis, and the raceway owner recommended a red fox guide. Since I hadn't ever actually bought a new one (I think I have some used ones) so I thought of this thread yesterday when I was building.

 

I laid 4 guides down on a block, the red one is a jet flag, c. 1983, above that is a parma, above that is a starburst from early 90's, and on top is the red fox. I looked at them all with a 25x magnifier, and lo and behold I noticed one "manufacturing" difference in them.

The  red fox has material that would indicate a seam on the form - at the top of the flag (right above the braid pockets, you'll see the excess material.)

The parma, starburst and jet flags seem to have the excess material at the bottom of the flag.

I spot checked 1/2 dozen jet flags, all had the same evidence. The starbust flags also seem consistent with this. Can someone check a number of RF and parma flags for the same?

 

PICTURES ATTACHED

 

I'm thinking this may create a weak spot in the flag.

 

pic 2019-01-27 10.35.37.jpg is the red fox guide.

2019-01-27 10.35.43 is a starburst (probably Camen branded)

2019-01-27 10.35.49 is parma

2019-01-27 10.35.55 is a jet flag (it's red, so easy to differentiate).

 

 

Attached Images

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[Bryan Warmack]

Bryan Warmack

 

Ask him. I ask earlier but suspect he is very busy this weekend.

   Eddie,

         Here is a "bumper" car I've been running recently and the front bumper addition was brought about primarily to eliminate dnf's caused by broken guides with most of my problems being a left hand side split braid pocket. This car was 5th in last years Checkpoint Can Am and runs very well but the extra few grams added in the front probably doesn't help it's performance.   However........with the bumper, it often and unquestionably plows through some wrecks completely immune to the surrounding carnage!  Changing braid is a bit tricky but no problem.

 

[MSwiss]

After a pretty dismal race on Saturday, I elected to replace my chassis, and the raceway owner recommended a red fox guide. Since I hadn't ever actually bought a new one (I think I have some used ones) so I thought of this thread yesterday when I was building.
 
I laid 4 guides down on a block, the red one is a jet flag, c. 1983, above that is a parma, above that is a starburst from early 90's, and on top is the red fox. I looked at them all with a 25x magnifier, and lo and behold I noticed one "manufacturing" difference in them.
The  red fox has material that would indicate a seam on the form - at the top of the flag (right above the braid pockets, you'll see the excess material.)
The parma, starburst and jet flags seem to have the excess material at the bottom of the flag.
I spot checked 1/2 dozen jet flags, all had the same evidence. The starbust flags also seem consistent with this. Can someone check a number of RF and parma flags for the same?
 
PICTURES ATTACHED
 
I'm thinking this may create a weak spot in the flag.
 
pic 2019-01-27 10.35.37.jpg is the red fox guide.
2019-01-27 10.35.43 is a starburst (probably Camen branded)
2019-01-27 10.35.49 is parma
2019-01-27 10.35.55 is a jet flag (it's red, so easy to differentiate).
 
 

Thanks for the effort.

I'm not entirely sure where you mean, about a seam (maybe an arrow would help).

Regardless, I'm not the manufacturer and have no control over the process.

I'm looking for opinions on a fix to the existing guides.

I'm not looking to analyze any design flaws.

[Dave Crevie]

In response to Mike Reibman; The vestige you see around the braid pockets is "flash" from poor fit of the side core that creates the

pockets. This in itself does not weaken the part. It is a sign, though, that the mold is not being properly maintained. It could indicate

that the cores that create the pockets are also worn, and may have lost any draft, if it had been incorporated, through wear. Typically,

plastic injection molds don't use draft on cores of that type, so any wear could cause a reverse draft situation, where the core is 

actually bigger at the end that creates the bottom of the pocket closest to the post. That means that as the core pulls out of the part,

it could stretch the material around the pocket and cause a small crack. All that being said, I don't think that any of that is why the

flags are being damaged. I have seen this type of damage to flags as long as I can remember.

 

i would also like to amend what I said in post 64 about the inlet vestige. After I logged off yesterday, I dug out all the guides I have, and

found that the Starburst graphite flags have the inlet vestige at the rear of the shoe. But I still don't think the flags are actually defective.    

[mreibman]

In response to Mike Reibman; The vestige you see around the braid pockets is "flash" from poor fit of the side core that creates the

pockets. This in itself does not weaken the part. It is a sign, though, that the mold is not being properly maintained. It could indicate

that the cores that create the pockets are also worn, and may have lost any draft, if it had been incorporated, through wear. Typically,

plastic injection molds don't use draft on cores of that type, so any wear could cause a reverse draft situation, where the core is 

actually bigger at the end that creates the bottom of the pocket closest to the post. That means that as the core pulls out of the part,

it could stretch the material around the pocket and cause a small crack. All that being said, I don't think that any of that is why the

flags are being damaged. I have seen this type of damage to flags as long as I can remember.

 

i would also like to amend what I said in post 64 about the inlet vestige. After I logged off yesterday, I dug out all the guides I have, and

found that the Starburst graphite flags have the inlet vestige at the rear of the shoe. But I still don't think the flags are actually defective.    

 

My head will not stop spinning... this is why I am not an engineer.

 

@MikeSwiss, not really looking at it all as a problem so much as a difference that might cause the problem.

[gotboostedvr6]

Pin the front of the blade. Leave enough piano wire hanging out of the front to block any impact damage from a front end collision.

[Eddie Fleming]

The Red Fox braid pocket is a tight fit with braid and a wire clip inserted. That is putting pressure on the top of the guide. Are you better off to run braid without the dimple or possibly flatten out the dimple taking a little pressure off?