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Learning how to build Lotus Seven replicas...together!
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 Post subject: Crazy Se7en Racecar
PostPosted: September 15, 2007, 10:55 pm 
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Hey here a wild one for you...Somehow I can't stop giggling like a little girl in front of Justin Timberlake 8)

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The details I can mak out are...
Engine is a Ford Zetec 1.8L, plenty of set back and offset...looks to be in the passenger footwell.
Tranny is a Ford T9
inboard front shocks
Inboard rear brakes
Side mounted radiators, hence the side pod. If you look closely you will notice no rad in the nose just a duct to vent the air upwards...

Here a few construction pics
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Di I say I like it :twisted:


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PostPosted: September 16, 2007, 4:11 am 
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Ohhhhhhhhhhhhhhhhhhhhhh....I like the inboard brakes. (and the flames out of the exhaust)

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PostPosted: September 16, 2007, 7:34 am 
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Look at how long the rear suspension links are! They go up to the front of the passenger compartment.

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PostPosted: March 31, 2008, 6:10 pm 
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I like it. I would really like to develop our car in the future along those lines.


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PostPosted: March 31, 2008, 9:45 pm 
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The voice of reason
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Those rear uprights really look nice.

Does anyone recognize the diff?

Does anyone know the tradeoffs on setting up the rear suspension with the long radius rods instead of the type of wishbones used on normal IRS locosts? Not wondering about space or practicality for the street, just wondering why that setup is so common on racecars...

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PostPosted: April 1, 2008, 12:07 am 
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The t9 tailshaft appears to fall on the rear bulkhead, roughly centered under the passenger seat... yet the differential appears to be centered. How do you make THAT connection? I've seen that amount of offset before.... Do Oswego supermodifieds now have a future on road courses?


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PostPosted: April 2, 2008, 6:03 pm 
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Very nice!

My review (FWIW)

The side pods: Excellent! Good looking, and adds impact protection. Can add more downforce if designed well. Good radiator location.
The front/mid engine: Excellent! Centralizes weight better and how much leg room does a passenger need anyway?
Inboard rear brakes: Trick! and lowers unsprung weight a bit.
Long rear suspension arms: Great! reduces the arc of the rear axle.
Rear wing: So-so. Not getting clean air as mounted.

Overall Two thumbs up!


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PostPosted: April 2, 2008, 9:19 pm 
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I don't get the crazy-long trailing links. I understand the theory, but wonder if he thought about the forces involved. Under hard acceleration I'd be afraid the lower tube would buckle. I mean, think about applying 100's of lbs of compressive force to what appears to be 5ft long thin tubes....

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PostPosted: April 2, 2008, 9:48 pm 
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KB58 wrote:
I don't get the crazy-long trailing links. I understand the theory, but wonder if he thought about the forces involved. Under hard acceleration I'd be afraid the lower tube would buckle. I mean, think about applying 100's of lbs of compressive force to what appears to be 5ft long thin tubes....


Have you never seen an early Formula Ford?

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PostPosted: April 2, 2008, 10:31 pm 
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Very interesting twist on the 7 chassis.

I've never been a big fan of inboard brakes. The reverse loading from braking isn't going to do the halfshafts any favors, but what I really turns me off to them is the fact that a failed halfshaft is going to cause you to have asymmetrical braking.

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PostPosted: April 2, 2008, 11:06 pm 
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modernbeat wrote:
Have you never seen an early Formula Ford?


I suspect that:
1. The early formula car design engineer calculated that it would work.
2. The early formula car weighs less.
3. The trailing links are shorter on the formula car.
4. Given the age, the formula car may have less power.

The true test will be if he spins around backwards and gets on the brakes hard... Lastly, if he spins into something backwards, there's a 50% chance that the upper trailing link will bend inward toward the driver. All I'm saying is that before I'd ride in the car, I'd have a discussion with the builder to see if it was built safe.

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Last edited by Anonymous on April 2, 2008, 11:34 pm, edited 1 time in total.

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PostPosted: April 2, 2008, 11:25 pm 
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I Think the engine is mounted a la Black Brick
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That would solve some issue...

If the rear suspention would be solid or De dion I would understand why the long trailing arms, but it isn't... Somehow I suspect some Lotus 7-20 inspired design.... inboard brake... Long trailing arms etc..etc.. If you look really close you will notice that the rear wheels seem a bit forward compared to a regular seven. Would it leave enought space for proper A-Arms ?

Fred


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PostPosted: April 3, 2008, 8:48 am 
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The trailing arms arn't as long as they look in the later pictures. If you look at the first picture of the car, from the side on the track they don't look much longer then the drivers arms. The picture with the long arms also make the driveshaft look about 6 feet long.

There would be room for normal arms.

If he is using U-joints, it's important for them each to operate at the same angle, so nit sure the black brick solution is correct. Perhaps in that case the motor angle is exagerated because the builder choose to get the equal angle the other way.

a.moore, inboard brakes are a big help on unsprung weight. You have the driveshafts anyway, so you should use them. Failed halfshafts are a nightmare - just to start you will be lucky for the wheel to remain connected to the car. I wouldn't want to think the flailing might include the back of the driver, but on these cars it might be possible.

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PostPosted: April 3, 2008, 10:31 am 
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mcteardrops wrote:
The t9 tailshaft appears to fall on the rear bulkhead, roughly centered under the passenger seat... yet the differential appears to be centered. How do you make THAT connection? I've seen that amount of offset before.... Do Oswego supermodifieds now have a future on road courses?


I thught that too, until I studied all the pictures more carefully.
The engine is not offset at all. Note in the 5th construction picture that the cam cover is 6-7" ahead of the firewall. The first construction picture is at a diagonal that projects the top of the engine further to the passenger side because your eye doesn't account for how far the engine is forward of the surface you're referencing it to. Also note the bottom horizontal member across the front of the passenger footwell in picture 2... looks like the passenger footwell is nornal full width... and in the same picture note the distance, at the front of the engine, from the timing belt idler (engine CL) to the frame rail on eac side.
I can't say absolutely that the engine isn't offset 1" but it's not more than that.

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PostPosted: April 4, 2008, 4:00 pm 
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KB58 wrote:

I suspect that:
1. The early formula car design engineer calculated that it would work.
2. The early formula car weighs less.
3. The trailing links are shorter on the formula car.
4. Given the age, the formula car may have less power.

The true test will be if he spins around backwards and gets on the brakes hard... Lastly, if he spins into something backwards, there's a 50% chance that the upper trailing link will bend inward toward the driver. All I'm saying is that before I'd ride in the car, I'd have a discussion with the builder to see if it was built safe.


Look at the classic clubman cars, very similar to a racing 7, all have the long trailing links.

http://www.classic-clubmans.co.uk/

Also a lot of 60-70's F1 and Indy cars had them, where 2 & 3 is probably not true, and 4 is definitely not true compared to a typical 7.


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