GT class--buggy-based on road!
12-11-2009, 02:01 PM
#2656
Suspended
That carbon fiber chassis is something i want to see in person ... how it performs so far ?, do you have a long chassis version for OFNA ? ... can you comment on HEAT DISSIPATION ?, in offroad 1/8 nitro some companies have made carbon fiber chassis with no much luck due to the carbon fiber not dissipating enouhg heat from engine ....
That will be a very light weight = fast DM SPEC man !!
cya
Pato Concha
Southamerica
That will be a very light weight = fast DM SPEC man !!
cya
Pato Concha
Southamerica
It cuts the chassis weight in half. Instant noticable increase in acceleration and top speed.
www.maxvelocityracing.com
12-12-2009, 10:32 AM
#2657
An aluminum chassis assists the engine at achieving a constant temperature during racing because of the heat soak/transfer properties of the engine block and mounts. Could you help us understand why this property is a problem?
Also you mention only one engine test. What combinations of engines, racing conditions and ambient temperatures has the carbon fiber chassis been tested in to prove that it will not be detrimental to engine life?
Also you mention only one engine test. What combinations of engines, racing conditions and ambient temperatures has the carbon fiber chassis been tested in to prove that it will not be detrimental to engine life?
12-12-2009, 07:33 PM
#2658
Tech Addict
I was looking at this chassis but that (temperature dissipation) is my main consern
12-14-2009, 04:49 AM
#2660
We have a few guys that run the Ipamema 2 speed. Yes you'll have to cut the servo mount
12-14-2009, 11:49 AM
#2662
Suspended
An aluminum chassis assists the engine at achieving a constant temperature during racing because of the heat soak/transfer properties of the engine block and mounts. Could you help us understand why this property is a problem?
Also you mention only one engine test. What combinations of engines, racing conditions and ambient temperatures has the carbon fiber chassis been tested in to prove that it will not be detrimental to engine life?
Also you mention only one engine test. What combinations of engines, racing conditions and ambient temperatures has the carbon fiber chassis been tested in to prove that it will not be detrimental to engine life?
For now I will make a general comment addressing your legitimate question.
There are 3 main paths that allow heat to escape the engine (not counting radiation). The exhaust gas, forced convection over the head, and conduction through the engine mounts. The heat removed through the engine mounts is a small percentage compared to that remove from the head and the exhaust combined. Lets be generous and say 15% of the engine heat escapes through the engine mounts. The amount of heat transfer is directly related to the amount of surface area that is engaged (.5 inches^2 for the engine mounts and approx 60 inches^2 for the head). Now lets say that your heat transfer to the carbon fiber is half as good and now only 7.5% is leaving into the chassis. Now lets say that engine life is directly related to the amount of heat that leaves the engine. So you would be loosing the 7.5% with carbon fiber. If you ran your engine 100 days with an aluminum chassis you would run it 92.5 days with a carbon fiber chassis.
But you would be running faster.
There is the trade. As far as engine life technically you could run you engine richer and go the same velocity because you would be lighter.
These are generalized comments the video response will be an apples to apples test.
12-14-2009, 12:04 PM
#2663
I will submit a video test of the same engine run on an aluminum chassis and a carbon fiber chassis and we can compare engine temperature and speed. I think that is the best way to address the question.
For now I will make a general comment addressing your legitimate question.
There are 3 main paths that allow heat to escape the engine (not counting radiation). The exhaust gas, forced convection over the head, and conduction through the engine mounts. The heat removed through the engine mounts is a small percentage compared to that remove from the head and the exhaust combined. Lets be generous and say 15% of the engine heat escapes through the engine mounts. The amount of heat transfer is directly related to the amount of surface area that is engaged (.5 inches^2 for the engine mounts and approx 60 inches^2 for the head). Now lets say that your heat transfer to the carbon fiber is half as good and now only 7.5% is leaving into the chassis. Now lets say that engine life is directly related to the amount of heat that leaves the engine. So you would be loosing the 7.5% with carbon fiber. If you ran your engine 100 days with an aluminum chassis you would run it 92.5 days with a carbon fiber chassis.
But you would be running faster.
There is the trade. As far as engine life technically you could run you engine richer and go the same velocity because you would be lighter.
These are generalized comments the video response will be an apples to apples test.
For now I will make a general comment addressing your legitimate question.
There are 3 main paths that allow heat to escape the engine (not counting radiation). The exhaust gas, forced convection over the head, and conduction through the engine mounts. The heat removed through the engine mounts is a small percentage compared to that remove from the head and the exhaust combined. Lets be generous and say 15% of the engine heat escapes through the engine mounts. The amount of heat transfer is directly related to the amount of surface area that is engaged (.5 inches^2 for the engine mounts and approx 60 inches^2 for the head). Now lets say that your heat transfer to the carbon fiber is half as good and now only 7.5% is leaving into the chassis. Now lets say that engine life is directly related to the amount of heat that leaves the engine. So you would be loosing the 7.5% with carbon fiber. If you ran your engine 100 days with an aluminum chassis you would run it 92.5 days with a carbon fiber chassis.
But you would be running faster.
There is the trade. As far as engine life technically you could run you engine richer and go the same velocity because you would be lighter.
These are generalized comments the video response will be an apples to apples test.
Thanks man !! (your name ?),
In my case, im not preocupied with "engine life", as it will be relatd to other variables, my concern its about racing temperature of the engine, nothing else. I already tested a carbon fiber 1/8 Buggy Offroad chassis, nad main problem was the heat that was present on the chassis plate itself, so finally the engine was running higher in temperature and not providing full performance. And well in offroad other variables were present as high wear of the chassis and big jumps resistance, wich is not related to onroad.
I love to try new things, any chance that in the near future you have a long chassis OFNA DM ONE-fit chassis available ?
thanks !!
Pato Concha
Southamerica
12-14-2009, 03:07 PM
#2664
Tech Addict
I will submit a video test of the same engine run on an aluminum chassis and a carbon fiber chassis and we can compare engine temperature and speed. I think that is the best way to address the question.
For now I will make a general comment addressing your legitimate question.
There are 3 main paths that allow heat to escape the engine (not counting radiation). The exhaust gas, forced convection over the head, and conduction through the engine mounts. The heat removed through the engine mounts is a small percentage compared to that remove from the head and the exhaust combined. Lets be generous and say 15% of the engine heat escapes through the engine mounts. The amount of heat transfer is directly related to the amount of surface area that is engaged (.5 inches^2 for the engine mounts and approx 60 inches^2 for the head). Now lets say that your heat transfer to the carbon fiber is half as good and now only 7.5% is leaving into the chassis. Now lets say that engine life is directly related to the amount of heat that leaves the engine. So you would be loosing the 7.5% with carbon fiber. If you ran your engine 100 days with an aluminum chassis you would run it 92.5 days with a carbon fiber chassis.
But you would be running faster.
There is the trade. As far as engine life technically you could run you engine richer and go the same velocity because you would be lighter.
These are generalized comments the video response will be an apples to apples test.
For now I will make a general comment addressing your legitimate question.
There are 3 main paths that allow heat to escape the engine (not counting radiation). The exhaust gas, forced convection over the head, and conduction through the engine mounts. The heat removed through the engine mounts is a small percentage compared to that remove from the head and the exhaust combined. Lets be generous and say 15% of the engine heat escapes through the engine mounts. The amount of heat transfer is directly related to the amount of surface area that is engaged (.5 inches^2 for the engine mounts and approx 60 inches^2 for the head). Now lets say that your heat transfer to the carbon fiber is half as good and now only 7.5% is leaving into the chassis. Now lets say that engine life is directly related to the amount of heat that leaves the engine. So you would be loosing the 7.5% with carbon fiber. If you ran your engine 100 days with an aluminum chassis you would run it 92.5 days with a carbon fiber chassis.
But you would be running faster.
There is the trade. As far as engine life technically you could run you engine richer and go the same velocity because you would be lighter.
These are generalized comments the video response will be an apples to apples test.
12-16-2009, 09:57 AM
#2665
Over on the 2011 worlds thread someone mentioned that the homestead track will be expanded by the time the GT race is thi true ???
12-16-2009, 11:25 AM
#2667
An aluminum chassis assists the engine at achieving a constant temperature during racing because of the heat soak/transfer properties of the engine block and mounts. Could you help us understand why this property is a problem?
Also you mention only one engine test. What combinations of engines, racing conditions and ambient temperatures has the carbon fiber chassis been tested in to prove that it will not be detrimental to engine life?
Also you mention only one engine test. What combinations of engines, racing conditions and ambient temperatures has the carbon fiber chassis been tested in to prove that it will not be detrimental to engine life?
The chassis pulls heat mostly from the engine block. In all but the hottest conditions, that's not always ideal. In discussions with Dave Gierke, who is one of the most experienced engineers in the world as it relates to nitro engines, we talked about the fact that over-cooling the engine block can have a negative effect on the power and efficiency of the engine. The heat in the block helps to keep fuel vaporized, which makes it burn most effectively, producing more power and consistency. Tapping into the conductive cooling of the chassis can cool the block to the point that the air/fuel mixture condenses, which begins to effect all the aforementioned in a negative manner.
Speaking of conductive cooling, another undesirable aspect of cooling through the chassis is the amount of time it takes to saturate with heat. Tuning an engine in the amount of time available at most big events is guess work because the chassis is far from saturated in just the minute or two of warm-up time allowed. It generally takes about 7-8 minutes of running at full speed for the engine and chassis to completely saturate with heat and stabilize - in colder weather it takes longer. It means you basically have to guess at your mixture setting and this is the number one reason you see engines going lean during the course of a main. Once you get enough experience, it becomes easier to guess, but it's not ideal for the average enthusiast.
Insulating the engine from the conductive cooling of the chassis allows the engine to heat up and saturate more quickly, which makes tuning a lot easier and more accurate, so for practical purposes the engine is LESS likely to be damaged by someone who's not an expert tuner. Even as a skilled tuner (if I can say so myself without sounding too full of it) I preferred the behavior of the engine when insulated from the chassis. The acceleration was a little stronger, the fuel economy improved, and there was no measurable loss of engine life. The changes are subtle but definitely notable. Also keep in mind that ABC engines NEED heat to get the sleeve to expand fully, so there's no correlation between nominal heat increases and engine life. In fact I believe that the engine life is as good or better because when the sleeve fully expands (and faster than normal) there's less stress on the engine internals (bushings, bearings, etc.).
I continue to insulate the engine from the chassis to this day because of that experiment starting about 10 years ago. This isn't the same as running a graphite chassis. Graphite is a little more thermally conductive than the insulating material that I use, so it probably cools the engine block more than I would prefer, but certainly less than conventional aluminum mounts and chassis plate.
12-16-2009, 12:11 PM
#2669
We are rushing for completion in time because of the great turnout expected for this event. There will also be a much higher and longer drivers stand that will easily be able to accommodate 15 or more drivers during practice.
Homestead RC Raceway is looking forward to having all of the GT Racers entered having a great time and provide you with a memorable racing experience.
12-16-2009, 12:15 PM
#2670
Suspended
Interesting stuff SteveP. I did not know that insulating the engine had such a potentially positive effect. The points you layed out make sense. Thank you.
I plan to shoot that video comparison saturday so I hope the weather cooperates. It will be a good addition to the conversation. It will be cool to get some real numbers.
A carbon fiber chassis has the potential to be a bigger benefit than I thought.
Benifits
1) Maintain a more constant tune by allowing the engine to reach a thermal equalibrium sooner
2)Allows the engine to run more efficiently by increasing fuel vaporization
3) Increased engine life by allowing engine parts to expand at preferable rates to decrease internal stresses (due to differing rates of thermal expansion between ABC components)
4) 1/2 the weight of aluminum.
Video to come soon
I plan to shoot that video comparison saturday so I hope the weather cooperates. It will be a good addition to the conversation. It will be cool to get some real numbers.
A carbon fiber chassis has the potential to be a bigger benefit than I thought.
Benifits
1) Maintain a more constant tune by allowing the engine to reach a thermal equalibrium sooner
2)Allows the engine to run more efficiently by increasing fuel vaporization
3) Increased engine life by allowing engine parts to expand at preferable rates to decrease internal stresses (due to differing rates of thermal expansion between ABC components)
4) 1/2 the weight of aluminum.
Video to come soon