F1 in Schools - Aero Racing help

[AeroRacingDubai]

Hi, I'm competing in the F1 in Schools competition in Dubai, and I just have some issues about the weight of components of my car.

There's a picture of the car design on the link below, but I'm not asking for advice on changing it for aerodynamic purposes or anything, though of course I'll listen if you have any. According to SolidWorks the balsa body itself will weigh about 25 grams when manufactured. It says the carbon fibre axles we've decided on will weigh approx. 2.3 grams each, although theres an option of 4 different types of carbon fibres at different densities so I'm not sure which it is.

I recently made a set of PTFE wheels using the machining lathe in the DT lab at school, diameter 30mm with a 25mm diameter hollow, rough design also in the link. We were hoping for the hollow to be 28mm, but they only had a 25mm drill bit. When I got home and weighed them I was disgusted to find they each weighed 10 grams, so I've decided to decrease the wheel diameter to 26mm, the minimum allowed, with a 25mm hollow. SolidWorks says these should weigh about 3.4 grams each.

This brings the overall weight to 45 grams, give or take a bit. The minimum allowed is 55 grams (which we're aiming for), and we still haven't taken paint into account. I was just wondering how much on average the paint would weigh, since I cant find anything on it anywhere. If it's more than 10 grams, I'll need to make some changes, like hollowing out the car design or making the wheels out of something lighter. Any thoughts?

http://www.flickr.com/photos/70865476@N ... hotostream

[flynfrog]

Hi, I'm competing in the F1 in Schools competition in Dubai, and I just have some issues about the weight of components of my car.

There's a picture of the car design on the link below, but I'm not asking for advice on changing it for aerodynamic purposes or anything, though of course I'll listen if you have any. According to SolidWorks the balsa body itself will weigh about 25 grams when manufactured. It says the carbon fibre axles we've decided on will weigh approx. 2.3 grams each, although theres an option of 4 different types of carbon fibres at different densities so I'm not sure which it is.

I recently made a set of PTFE wheels using the machining lathe in the DT lab at school, diameter 30mm with a 25mm diameter hollow, rough design also in the link. We were hoping for the hollow to be 28mm, but they only had a 25mm drill bit. When I got home and weighed them I was disgusted to find they each weighed 10 grams, so I've decided to decrease the wheel diameter to 26mm, the minimum allowed, with a 25mm hollow. SolidWorks says these should weigh about 3.4 grams each.

This brings the overall weight to 45 grams, give or take a bit. The minimum allowed is 55 grams (which we're aiming for), and we still haven't taken paint into account. I was just wondering how much on average the paint would weigh, since I cant find anything on it anywhere. If it's more than 10 grams, I'll need to make some changes, like hollowing out the car design or making the wheels out of something lighter. Any thoughts?

http://www.flickr.com/photos/70865476@N ... hotostream

Why not do a test panel paint a panel of known surface area weigh it then use SW to determine the surface area of your car.

[teamhastef1]

Hi Aero Racing,

Well, Solidworks is not competely accurate all the time so you do have to, as Flyn Frog said, make your own observation and approximate estimation.

When we had our internal finals at The School of Research Science, our car was weighed at 15.32 grams without the wheels, axles or any other external parts, and ended up at 35 or so grams after painting,but the F1 in Schools UAE default wheels were around 20 grams, so we did reach about 55 grams. Not sure as I didn't wigh the car after the first weight check, but I know it was within rules and regs. I suggest your car be around 40 grams with your complete chassis.

The second option is to do what FlynFrog said, to check out the surface area of your car in Solidworks, (in the evaluate tab, 'masss properties') and once thats done, get something with a known surface area similar to your car and check the weight difference before and after painting it.

Hope it helped

[AeroRacingDubai]

Okay thanks, I hadn't thought of that. I know solid works isn't perfectly accurate but it did give us a pretty good estimate on the weight of the wheels we made. That design was illegal in a number of ways so we've redesigned and the new one is about 20 grams, and with the PTFE wheels we're making at 4 grams each, then axles, bearings etc it'll probably come to yeah about 40 unpainted. And at least for the internal competition we'll probably paint it ourselves so that'll give some control over how much weight we put on. Thanks for the help

Now we just need to raise the money for manufacture -.-

[teamhastef1]

No problem, but make sure when you use solidworks you think about it with a +-2grams uncertainty.
Now I remember how much our car weighed before we painted it, with axles, wheels and bearings, it came to the late 40s, so yo should be fine.

Since you don't have any monetary sponsors yet, how are you planning to manufacture Carbon fibre axles and where from?

I had a look at your car, and it didn't seem illegal to me, but 20 grams for a car, added to the rest of your components should make it perfectly fine. make sure you spray paint your car, not with a paintbrush so your layers can be evenly set

It is getting harder and harder to get sponsors

[graham.reeds]

Not knowing much about the F1 in Schools project, can you have closer fairings around the wheels? Also the front wing seems to be pushing a lot of air under the car and that slight lip isn't going to help.

Have you ran the model through CFD?

How much freedom does the project allow?

[fischele]

When we designed our car we faced similar issues. In CAD it said it would weigh 53g, the minimum was 55,5g.
We measured the ring bolts to be about 0,4g each , so the paint ( which was very thick) only made up for about 1,5g.
In the end our first car wheighed 55,8g, the second one 55,65g.