Over and Under or around the sides

[BreezyRacer]

I quite agree with you Breezy, It most certainly does not, but you don't want to show your hand in the event that doesn't count - do you?

Good point .. just keep the fire lit!

[greenpower dude reloaded]

Haha! Will do. I went along to Donnington Park today to get me even more in the mood for a bit racing tomorrow.

Assuming the reliability is there we have every possibility of placing on the podium, but if we do, we'll likely have done it on less power.

[greenpower dude reloaded]

Yes, I know, I have been lax with all of this recently, but I've been really quite busy with projects both at work and at home and trying to make the two the same thing!!

Well, as I'd left it last time we were prepping for the Corporate Challenge which is set up more as a bit of fun than it's a serious race. Or at least that's my viewpoint. I've no doubt that many others would disagree. The idea is that us “amateurs” have laid down the gauntlet for the “professionals” but they invariably get beaten by us small teams. As you’d expect really, they only enter one event a year where as we may compete in 6 or so..

The weather was absolutely atrocious - just horrendous. We had entered the season opener to try and get a bit of a feeling for wet weather set up before the main race and weren't there to race the guys at the front.

I started the race in dead last (50th) with the aim of complete two flyers and then box. By the end of our 3rd complete lap we were up to 5th and by the time we pit we had just made it in to a podium position (could have been any one of the three, I'm really not sure, the timing loop obviously didn't pick that up)

I had set fastest lap and sent Laura out on a marginally more conservative gearing, she did great but reported a sticky throttle. It's obviously quite important that issues like that are dealt with as soon as possible. Safety is paramount.

Long story short the speed controller popped and I decided that rather than replace it we ought not to turn a £60 issue in to a £120 issue (money really is that tight:() . The weather was just horrendous as well - I had aquaplaned under braking in a couple of areas. You may think of us as wimps for throwing in the towel (then picking it up again and drying ourselves off.) The trouble is, when you've poured your heart and soul in to a vehicle that's taken 10years to get to the point we are at now, you don't want to throw it all away on a race that's "just for fun."

So we got the car back and I was thinking…. Maybe it is time to call it a day. Naturally that didn’t last long and we were back on track for the first round of the F24+ Championship at Goodwood (again).

We had made a couple of changes but nothing more than just making pit stops easier (for the newer followers the race is 1.5 hours long and each team is given 4 x 12v 35a/hr batteries, two of which must be on the vehicle at any one time.)

We went in to the event reasonably confident, but knew we had a few teams to be wary of. Unlike last years final, It could well be an every second counts sort of event, which, as I’m sure any other competition vehicle designers on here will agree, that’s not the sort of event you want. Whilst I’m often quite guilty of playing it pretty safe in terms of regulations, I’m always looking for that unfair advantage!

So, we sent Laura out on the same gearing that we had run at the National Final last year. She completed 2 flying laps then came in. I pulled up the datalog and saw that we were actually using marginally less power than before, so we had a vote and decided to take the risk and up the gearing slightly. This is the result of a combination of things, certainly, both the fact that Laura 20kgs lighter than me and that we’d made a few small aero tweaks underneath the car.

The start of the race came at 11am and as soon as I’d pushed the car off the line, I noticed she was making a very slow get away. My heart sank… she kept going though and by the end of the first lap she was back up in to 3rd. Unfortunately, having now won an event at that circuit, my expectations have changed somewhat so for the first few seconds, I wasn’t too happy about 3rd place, I quite quickly realised that over one lap she’d made up considerable ground against the cars in 1st and 2nd. Maybe things were going to be ok after all.

All three of the cars at the front of the pack piled in to Woodcote and the front two cars, now us in P2 and Elec-track in P1 made a break for it down the start finish straight. Laura tucked the car up nicely behind P1 and pulled out and round some traffic, leaving elec-track with no choice but to take the long way round. From then on in Laura eked more of a lead with each lap, finishing the race in P1 a whole lap up on P2, and very nearly 2 laps up on P3.
So, next Monday we’re off to Rockingham our second round of the Championship. Fingers crossed, we can take home some decent points!

[flynfrog]

Nice results mate. Looks like you are really getting that car dialed

[BreezyRacer]

Kill it this week .. sounds like you have a complete understanding of what it takes to master the grid!

[greenpower dude reloaded]

Thanks very much guys! We've got big plans for this next one but only track time will tell us whether they're actually going to deliver.

What will be fascinating is that we'll have our other car there too.

I've been getting better with this whole twitter malarkey and have started tweeting during events. So don't forget to follow @Horsfallracing

[flynfrog]

GPDR What would you do differently on your next car. What lessons have you learned from this one? Did you ever do any coat down testing to get your real drag numbers.

[greenpower dude reloaded]

I've just got in the door and was thinking on the drive back from Rockingham. This is a technical forum and I've not been very technical recently so VERY good question.

Lets get the boring non-techy stuff out the way first..
Long story short, we won today. It's still the most surreal thing saying that we're able to win consistently but we've now won back to back events which keeps us ahead in the championship standings.

F24+ is a bit of an odd championship. The points that count to overall standings are that of your best two regional heats and the National Final, there are other heats than the two we've been two but transporting the car is surprisingly difficult to organise.

A few quick figures (that we're very proud of) for the statisticians amongst you.
The distance record under the current regulations at Rockingham was 48.5miles in 1.5hrs - Today we completed 57.3miles

The previous lap record was 2mins 23secs - Today only 8 of 39 laps (including from a standing start and pit in and out laps) were over that. Our fastest lap was 2mins 9 secs which is a 40.8mph average speed!

Ok, so what would I do differently...

As far as chassis construction goes, I would have pursued a carbon monocoque, we've currently got a semi monocoque with very heavy vac formed ABS panels. I have started construction on a new chassis but this is quite likely to be shelved. I've also started taking female moulds from the body (we only had male moulds prior to this) and making CF replacements. It looks as though we'll save well in excess of 2/3 of the weight from the body if I can replace all of the panels. It's a massive job, there are about 11 formings in total.

I'd really like to try out different types of chain/belt/spur gear to see which is the most efficient form of transmitting power. The only thing I know for sure is that the chain we use at the moment isn't the most efficient.

The biggest thing on the wish list is actual wind tunnel time. I've contacted pretty much everyone I know of in the UK with a wind tunnel but to no avail. I suspect they get a lot of this sort thing. It would really help expand our broaden our knowledge of the car. I have been looking in to a few upgrades on CFD but there is very little that makes any difference.

Here are a couple of shots to help stimulate some aero suggestions.



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We've not conducted any coast down tests, mainly because we struggle to find anywhere to run the vehicle other than actually at events.

Other than that I think I would have made the cross sectional area a little smaller, but certainly not sizeably so.

[BreezyRacer]

Your efforts are looking like a million bucks. Time to monetize it. Time for paying sponsors?

[flynfrog]

my one suggestion would be a more aero friendly roll hoop.

You dont really need wind tunnel time or even a DAQ. Coast down test can tell you most of what you would learn in a wind tunnel. You would do some tuft testing to "see" your airflow.


One of the airplane I worked on never saw a wind tunnel all was done in CFD or real world.

I would think an empty parking lot would be easier to come by than a wind tunnel.

[flynfrog]

pimping my own thread but I do have some pictures of streamliners

viewtopic.php?f=5&t=13116

[greenpower dude reloaded]

Good point breezy, working on the newsletter + begging letters right now. It's amazing how many doors winning the final opened up for us.

Useful feedback Flyn, as ever.

Strangely anything else I've tried on CFD has always come out worse than the current set up as far as ROPS goes. The section used is elliptical with very tight radii at either end. It would be very tricky to roll to shape but I have run it in CFD as a hoop and it increased drag ever so slightly. Maybe we need to revisit that..

Tuft testing has been a serious thought for a while but the only real opportunity to do such a thing is at events and there is always a lot to be getting on with anyway. Car parks just aren't big enough. We need a runway ideally I've designed a neat little Roll hoop mounted boom mounting for a camera to film the tufts, far enough away that it won't affect what it's filming.

Those streamliners are awesome, I've no idea how I missed that thread. A particular favourite of mine is Beast III, naturally I just love all of the drop tank racers as well but Beast just has that look of refined Auto Union Type C about it! Very nice

[flynfrog]

Good point breezy, working on the newsletter + begging letters right now. It's amazing how many doors winning the final opened up for us.

Useful feedback Flyn, as ever.

Strangely anything else I've tried on CFD has always come out worse than the current set up as far as ROPS goes. The section used is elliptical with very tight radii at either end. It would be very tricky to roll to shape but I have run it in CFD as a hoop and it increased drag ever so slightly. Maybe we need to revisit that..

Tuft testing has been a serious thought for a while but the only real opportunity to do such a thing is at events and there is always a lot to be getting on with anyway. Car parks just aren't big enough. We need a runway ideally I've designed a neat little Roll hoop mounted boom mounting for a camera to film the tufts, far enough away that it won't affect what it's filming.

Those streamliners are awesome, I've no idea how I missed that thread. A particular favourite of mine is Beast III, naturally I just love all of the drop tank racers as well but Beast just has that look of refined Auto Union Type C about it! Very nice

remember you can always roll the hoop out of normal tube then build a fairing for it.

[greenpower dude reloaded]

I have looked in to it... But this square profile always comes out on top in CFD. I wish I could explain it, but i've not managed it yet. Sometimes it's easier to see why things don't work than how actually work successfully..

I PROMISE, i'll do some runs soon. Laid up in bed at the moment feeling like death warmed up, that either means you'll see something very soon or not for a week or two!

I think the only type of ROPS that would actually improve drag quite easily would be a blade type roll bar, but that's not strictly legal and difficult to carry out to a high enough level of build that I'd be happy to see my little sister driving it.

I apologise if I seem anti a new roll bar, I'm really not. I want to be proved wrong! I want to see a shape that'll help us go quicker!

[PhillipM]

What are you running in the way of the chain drive at the moment (apologies if I've missed it, I've missed a few pages here and there!), chain drive in general is pretty efficient if setup and lubricated well, I'd be surprised if it's costing you much power?