Sprinting a Mygale M12 Ecoboost

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DiogoBrand
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Re: Sprinting a Mygale M12 Ecoboost

Post by DiogoBrand » Mon Apr 04, 2016 7:00 pm

Then maybe your CFD will come in handy. You can get an idea of the best shape to make the floor in order to produce maximum df while keeping it from stalling. And if that involves poking your suspension through it, go for it.

andylaurence
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Re: Sprinting a Mygale M12 Ecoboost

Post by andylaurence » Sun May 15, 2016 7:34 pm

After Rockingham and the mental oversteer at speed, we had to sort out the aero balance before Rockingham. Rather optimistically, we decided to build an interim diffuser whilst we worked on the proper one in addition to fitting a new 4 element rear wing of larger chord, greater camber and 50% greater width. The diffuser mould started well, but we had air leaks in the mould, so the infusion couldn't be started and we ran out of time before it was fixed.

There was time to fit the rear wing though and it's a monster. The mount is a bit messy, but is functional and some tuft testing proved the wing is working, even if it's a little canted backwards. It's only an interim solution though.

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Importantly, the wing really worked and you can see the massive rooster tail generated without the help of a floor. The car understeered massively at speed despite the introduction of vortex encapsulating end plates on the front wing. The end result was a new class record although not by as much as I wanted.

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Unfortunately, a noise from the gearbox worried us on the day. A trip to Mark Bailey Racing concluded that an errant washer in the differential that shouldn't have been there was the cause. Luckily, we caught it before any damage was done.

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Now we need to get a bit more downforce at the front end before Crystal Palace over the bank holiday...

andylaurence
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Re: Sprinting a Mygale M12 Ecoboost

Post by andylaurence » Sun May 15, 2016 7:51 pm

Llandow was the first time Andrew had driven this season. It was a baptism of fire with the wet practice and Andrew was the first to experience driving through the puddles on slicks. In hindsight, wets were probably the better fitment. Andrew had a massive moment in first practice that knocked his confidence and he wasn’t back on the pace in the following runs.

Here’s how our final timed runs compared; Andrew in green and me in blue. The top graph shows speed, the middle graph throttle position and the lower graph both steering angle and brake pedal pressure.

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Off the line, there’s very little in it, but I launched at huge revs in comparison. We were similar on pace through the Bus Stop section but I used far more throttle between the apexes. Andrew dragged the brake through the right hander after the Bus Stop, whilst I used my customary prod of the throttle mid-corner. Ideas on how to stop myself doing that appreciated! I was early on the throttle though and this gave a small advantage.

I kept on the throttle later into the right hander that leads into the back straight and a short lift with no brake gave me a 10mph advantage onto the back straight. I was later on the brakes into the chicane, holding the brakes until turning into the second apex of the chicane. I also got on the power straight away coming out of the chicane, holding full throttle and a little more steering angle for a 6mph advantage.

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A short stab of the brakes coming into the final corner of the first lap allowed me to maintain a 5mph advantage through the corner and I was back at full throttle before Andrew was off the brakes. Andrew used more revs down the straight and was back on my pace by the end of the straight. I was later on the brakes and pressed much harder whilst Andrew took a few stabs at the brakes. That led to a maximum disparity of 25mph.

I turned into the chicane far more aggressively, whilst Andrew fed in the wheel. This was probably different lines, but I was turning into the second apex of the chicane earlier as a result. Andrew had a fair amount of oversteer mid-corner and that might be why I straightened up earlier and managed to get full throttle before the final apex of the chicane and again afterwards. This gained me up to 9mph.

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As a result of my extra speed out of the Bus Stop, I needed to hop on the brakes coming into the right-hander that follows, but only a short stab. Andrew balanced the car much more neatly as shown by the lesser steering angle into the corner. I was back hard on the throttle on the exit, which gave me a few mph into the next corner where we lifted at the same time. Andrew was off the throttle completely and dragged the brake a little, whilst I took a half-lift of the same period. You can see the understeer from the new rear wing in my increased steering angle.

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Coming into the chicane for the final time, I was later and harder on the brakes, but carried more speed through all 3 apexes. This led to a different line out of the chicane and that allowed Andrew to pick up to the same speed on the exit of the following right-hander, despite less throttle because he’d chosen third gear instead of fifth. Andrew braked longer into the final corner giving an apex speed about 5mph lower and continued to drag the brakes through the corner beyond the point I was on full throttle. He exited in third gear whilst I used fifth, which allowed him to catch up by the finish line.

flynfrog
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Re: Sprinting a Mygale M12 Ecoboost

Post by flynfrog » Mon May 16, 2016 1:21 am

Sorry I missed some updates Andy congrats on the win. The new wing looks pretty good to me. I'm looking forward to you running a track you have previously so you can quantify how well it works.

andylaurence
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Re: Sprinting a Mygale M12 Ecoboost

Post by andylaurence » Mon May 16, 2016 6:03 am

Llandow was the first return to the same track. I broke my own class record, but only by 0.01, which was disappointing. I should compare the data from last year to this...

Zynerji
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Re: Sprinting a Mygale M12 Ecoboost

Post by Zynerji » Fri Jun 03, 2016 4:28 pm

andylaurence wrote:Yep, Kinect with KScan3D. It's a little bumpy, but a start. When I get on my PC, I'll post some pictures. @andylaurence on Twitter has a few photos. Now seeking people with time and skills to help me develop a new floor through CFD...
I have read that if you put a small vibrating motor on the kinect (like from an old pager/radio shack) that the surface scans are dramatically better.


http://hackaday.com/2012/08/13/building ... ger-motor/

andylaurence
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Re: Sprinting a Mygale M12 Ecoboost

Post by andylaurence » Fri Jun 03, 2016 4:51 pm

Only for multiple sensors though...

Zynerji
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Re: Sprinting a Mygale M12 Ecoboost

Post by Zynerji » Fri Jun 03, 2016 5:07 pm

andylaurence wrote:Only for multiple sensors though...
That is addressed in the comments.

andylaurence
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Re: Sprinting a Mygale M12 Ecoboost

Post by andylaurence » Tue Jun 07, 2016 7:30 pm

At Llandow, the gearbox had been making a funny noise. We took it down to Mark Bailey Racing for an inspection and an errant washer in the diff assembly had shredded itself. With the swarf removed and a worn dog ring replaced, the gearbox was refitted and the oil cooler removed ready for the next event.

Motorsport at the Palace is an annual event through the pathways of Crystal Palace Gardens. Last year, I lost the Sports Libre class record to David Seaton, but gained the invitation class record with a PB of 34.02. This year, Andrew and I were sharing the car for the weekend with Andrew driving the Sunday and me on the Monday. With no racing car for the Sunday, I decided to enter the tow car for a bit of fun!

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In first practice, I was doing quite well, running midfield in the automatic diesel Astra estate. Unfortunately, as I went faster throughout the day, the car thought it was mid-accident and gave me a box of neutrals at each corner. The knack to a fast time was going as fast as you could without activating the emergency features. I lopped a tenth off on the last run, but that left me dead last in class. A manual gearbox would have been well over a second quicker.

Meanwhile, Andrew was doing well on his first non-circuit event. He slotted into 2nd place in class at the end of the day. The tight confines of the track and lack of experience at the venue really hampered his ability to chase the lead.

On Monday, it was all about the EgoBoost for me and time to reset my record. Pete in the similar car had managed a 33.97 in practice and I was determined to beat it. I didn't manage to hook up a decent run though and ended up with a tantalising 34.01 PB. Strangely, that's 0.01 quicker than my PB again! Unfortunately, I forgot to download the data, so we can't compare the two runs.

andylaurence
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Re: Sprinting a Mygale M12 Ecoboost

Post by andylaurence » Thu Jun 09, 2016 5:34 pm

After Crystal Palace, we had 4 days before Abingdon and the car was still understeering from Llandow, so we needed to throw the balance forwards. I decided it was best to add downforce at the front rather than trim it out from the rear, so I set to work with the 3D printer to create a pair of small winglets for the front wing. Using the profile of a Marussia 2013 beam wing, I shrunk it to the right size and printed two off. A quick sand down and they needed a wash so I stuck them under the tap. Gratuitous tap "aero" photo taken, of course!

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Just before the first run at Abingdon, I fitted them to the leading edge of the front wing end plate to make the most of the leverage from two such small devices. I kept the winglets away from the dip in the front wing end plate that creates a large vortex ahead of the front wheels in the hope that either the vortices would combine into a bigger one or that this extra vortex would apply a low pressure area to a different part of the tyre.

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The end result was a marked balance shift forwards from dramatic understeer at Llandow to a small rearwards balance at Abingdon. Next up, Castle Combe...

andylaurence
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Re: Sprinting a Mygale M12 Ecoboost

Post by andylaurence » Wed Aug 24, 2016 10:06 pm

After Abingdon, there was some damage to the front wing vortex generators, so new ones needed printing and this time, I made them a little tougher.

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I'd also spent some time at Prescott looking around an Empire Wraith, designed by Willem Toet, which gave some ideas about controlling front wheel wake. Some food for thought for 2017, perhaps?

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We also had the alternator moved to the engine rather than the rear axle to avoid the battery issues that have afflicted us this year.

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A new setup after all the changes this season showed we're down to 464kg and the car is now running at 61mm front and 72mm rear ride height. That's rather high considering the stepped floor, which is running at 122mm at the rear. Unfortunately, the gearbox also blew a seal at Abingdon, so off it came again to have the seal replaced.

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The balance was still off, so I printed a variety of gurney flaps for the front wing flaps to add more downforce if needed.

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Thinking of the future, I also knocked up an endplate-less front wing design.

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Last minute, I decided this was the last time the car was running without a diffuser, so searching around the house, I found some cardboard for templates and some aluminium sheet offcuts in the shed. An hour or so later...

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The diffuser was fitted in the paddock before scrutineering. The difference in first practice was frankly astonishing, but despite a 40mm ride height for the end plates, it scraped along the floor continually.

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Castle Combe went well with a new class record and a class win, despite a misfire in the afternoon. The car's now booked in at the rolling road for some diagnostics. Data debug to follow...

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bill shoe
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Re: Sprinting a Mygale M12 Ecoboost

Post by bill shoe » Thu Aug 25, 2016 3:14 am

Interesting saga, and congrats on class win!

NOT A TA
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Re: Sprinting a Mygale M12 Ecoboost

Post by NOT A TA » Thu Aug 25, 2016 4:58 pm

Been keeping up with your updates. Congrats on the class win. Do you think the diffuser was scraping more from deflection, suspension compression, or an equal combination of both?

andylaurence
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Re: Sprinting a Mygale M12 Ecoboost

Post by andylaurence » Thu Aug 25, 2016 5:06 pm

Suspension compression. The diffuser is tethered to the rear wing, so rather rigidly attached. Deflection would be minimal.