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Feb 2, 2015 21:38:20 GMT -7
Post by dave632 on Feb 2, 2015 21:38:20 GMT -7
When I did the test on the T jet I was curious to see how far the effect went. It only
applied to the stock T jet as stated.
I now have done some further testing to see if the effect was similar on faster cars.
I took a car that was running in the 28-31 MPH range.
My plan was to take the lightest car at 21 grams and add weight bringing it up to 27 grams, my heaviest car.
Trying to add weight and putting it on the top of one of these cars did not work at all. If I added the weight to the top it would lift the front end off the line and kill the ET. If I put it on or near the front of the car it would spin the tires and kill the ET. Little effect was seen in the MPH. I then took the body off and stuffed some weight inside to try to bring the weight up without effecting the stability. I added 5 grams bringing it up to 26 almost to the level of the heaviest car.
All ETs and mph readings were slightly slower. ET by 13 thousandths, 60' by 29 10 thousandths. MPH was only slightly effected losing only .2 tenths.
I then took the 27 gram car and simply pulled the body off. This brought it down to 19 grams which would
be lighter than most anything we would run.
The lighter, chassis only, car ran a consistent .02 or two hundredths quicker in ET. The 60'was actually slightly slower by a few thousandths meaning there was a little more wheelspin. The MPH was only slightly effected as all readings were within a few tenths of each other.
These were not my fastest cars but they were quick and all indications show that weight does slow you down, mostly in ET and only the tiny tired T jet defied all the rules.
Get out the grinder on your heavyweights, because I sure will, as it does make a difference.
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Feb 3, 2015 4:16:14 GMT -7
Post by AJR on Feb 3, 2015 4:16:14 GMT -7
From here on I am acting on the rules as they are currently written. I thought maybe this was overlooked, but the more I think about it, I don't think it was. A lot of time went into the restructuring of the rules for 2015. No more rules discussions for me unless it is a big deal. To me this is not. Super Nationals coming up......OH YEAH!!
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Feb 3, 2015 6:47:43 GMT -7
Post by dave632 on Feb 3, 2015 6:47:43 GMT -7
A good point.
Most likely it was a rule change, not an omission.
I think in some classes weight limits should be a factor while
in others, especially highly modified, there should be none.
I have proved to myself weight makes a difference except where very little traction is available.
As said, race the rules as they are written and have a good time.
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Feb 3, 2015 7:07:46 GMT -7
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Post by pceng on Feb 3, 2015 7:07:46 GMT -7
Yes a scale is one more tool to add to the bench but your going to need a few tools to build these cars. I think Doorslammer is the only class that has the weight restriction,it's not exactly an entry level class though either. At our race here we're going to have the hauler race, I had planned on putting a minimum weight in place to be able to make it fair between the different types of haulers that can be built but nothing is in stone,I'm open to ideas. Tom, is whole rig going to be needed ? ......... Peter |
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Feb 3, 2015 7:21:00 GMT -7
Post by TGM2054 on Feb 3, 2015 7:21:00 GMT -7
That's what I'm thinking. Whether it be a tractor trailer,rollback, or pick up with a trailer. Something a team would use haul a race car.
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Feb 3, 2015 7:30:43 GMT -7
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Post by pceng on Feb 3, 2015 7:30:43 GMT -7
That's what I'm thinking. Whether it be a tractor trailer,rollback, or pick up with a trailer. Something a team would use haul a race car. Cool, been thinking of something to carry car. With the car on it maybe I should use a Dash...... ;-).......lol. |
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Feb 3, 2015 7:38:08 GMT -7
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Post by pceng on Feb 3, 2015 7:38:08 GMT -7
From here on I am acting on the rules as they are currently written. I thought maybe this was overlooked, but the more I think about it, I don't think it was. A lot of time went into the restructuring of the rules for 2015. No more rules discussions for me unless it is a big deal. To me this is not. Super Nationals coming up......OH YEAH!! Whether it was omitted or not is what I was intrested in to begin with. Hope we do get word as to this....... ......... Peter |
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Feb 3, 2015 13:16:32 GMT -7
Post by Deleted on Feb 3, 2015 13:16:32 GMT -7
being a relative newbie HERE ......
has there been a weight distinction in the class in question previously?
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Feb 3, 2015 13:37:23 GMT -7
Post by AJR on Feb 3, 2015 13:37:23 GMT -7
Yes Al Doorslammer (25g) and MM\PS (22g) had weight minimums. I thought there was one more, but that might have been it.
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Feb 20, 2015 17:31:09 GMT -7
Post by FlatBlackCamaro on Feb 20, 2015 17:31:09 GMT -7
I can understand the ET since tire spin with those tiny tires would be effected but the MPH? I then added another 8 grams bringing the weight up to 37 grams or almost twice the starting weight. Again I was surprised as it went quicker and faster still. It averaged 1.7126 at 7.51 MPH. Once again I think the ET was helped by less tire spin but MPH getting better makes no sense to me. While reading this i think ive come up with an answer to why you gained MPH and youve almost answered it yourself. When you launch and your tires spin you lose real-estate, however high horsepower cars make up for the distance lost with power to weight. The ETs may be high but the MPH wont be due to how fast they got to X amount of speed. Take that same car that would typically spin an 8th down the track and give it more traction and it suddenly has more real-estate giving it ample reason to have more MPH and a quicker ET it simply has more room. |
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Feb 20, 2015 21:47:21 GMT -7
Post by dave632 on Feb 20, 2015 21:47:21 GMT -7
What confused me here is my experience with full size cars. I could blow the tires into big puffs of smoke and it would make little difference in my MPH.
These cars are different in that they can spin the tires so much it can and does effect MPH at the finish, which was proven by my experiment.
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Feb 21, 2015 9:13:21 GMT -7
Post by FlatBlackCamaro on Feb 21, 2015 9:13:21 GMT -7
I think with HO scale there could possibly be two types of wheel spin going on, especially in cases of high TQ/HP cars. You have two contact surfaces your trying to make one piece of rubber stick to. These are The Track of course and The Rim. I bet if someone had a high speed camera that you could catch rim spin at the tail end of a "burn out" when the car finally grabs. Ive had pretty extensive dragracing R/C cars. I had an Associated 1/8 Nitromethane 4.6cc with hop ups... it was fast like lightning fast. Before the new motor i put in the camaro it had the 5.7 tpi and it was semi hopped up, the R/C would beat the car almost half track stop sign to stop sign ( yes ive raced them ). I would wait with it in the driveway for people to drive by to lunge out and chase them, the truck was capable of 85mph full scale. Heres the point of all that : As the truck got closer to max speed and Very high RPMs the tires would swell almost double their size, the tires were held to the rims with a specialized glue that vulconized the rubber to the plastic. In one case i had a tire blow apart due to the high RPM and rotational force. What im getting at is that it could be possible that as the cars gain speed and RPM the rubber could be swelling in a fashion that only the tire and the track are connecting and it could possibly be spinning in the middle due to the fact there is nothing holding the tire to the rim. With full scale cars we have air or nitrogen.
Theres too many variables in converting MPH to RPM that wont match when talking cars and slots. So for the sake of it just take this as an exaple, if @ 50 MPH your tires travel 5,000 RPMs and the slot car that has wheels that are in Millimeters vs the 27" tall tire. You can only imagine what RPM they are spinning at going 50mph like some of yours do. I know its not feasible but i bet if you had a set of tires glued to rims and raced that its highly possible the car could potentially go even faster. I think at high speed centrifugal force is expanding the tires just a hair.
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Feb 21, 2015 9:39:23 GMT -7
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Post by pceng on Feb 21, 2015 9:39:23 GMT -7
Tire expansion usually dosen't happen until cars have been modified. Think some tires today are made with urethane expands less than silicone. All tires are best if glued & trued for slots.
Problem is finding something that will hold to silicone. Most glues won't. Recently picked up stuff from RC place they swear will hold any tire. Silicone ? Told me no such tire......... but we'll see what happens.
......... Peter
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Feb 21, 2015 12:16:04 GMT -7
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Post by FlatBlackCamaro on Feb 21, 2015 12:16:04 GMT -7
Yea i dont either peter lol i thought that was the sole purpose, repelle water and oil and not let anything stick to it in the process. Only way i know to get silicone to stick to anything is apply it wet, RTV red tires would look kinda funny... lol
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Feb 21, 2015 12:18:47 GMT -7
Post by dave632 on Feb 21, 2015 12:18:47 GMT -7
Absolutely right, when higher speeds are reached those tires are wanting to expand big time.
When I started to go faster glued on tires started to fly off the rims. Using tires that were low profile were a help but not a cure. Even front tires started to come off the rims when 50+ mph speeds started to be reached and they were on deeply grooved rims.
I once picked the rear end up off the ground on one of the high powered cars just to spin it as a test. It immediately flung both glued on tires off and they went spinning down the track onto the floor then hitting the wall.
Peter you need to go to a store where they have a clue!
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