MEV Rocket Build

Author
Discussion

rdodger

1,088 posts

202 months

Wednesday 14th December 2011
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Is the fuel tank in the passenger compartment? I didn't think that was allowed for IVA?

shaun fulcrum

107 posts

181 months

Thursday 15th December 2011
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First look at this thread! Dont know why but it has given me an urge to strip my car back the chassis and start again!!! Although that probably won't happen wink

Incredible attention to detail and finish.

Mabbx

Original Poster:

204 posts

208 months

Monday 19th December 2011
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rdodger said:
Is the fuel tank in the passenger compartment? I didn't think that was allowed for IVA?
Many of the rockets have this arangement. I believe if it is enclosed so that no potential fumes can escape from a possible spilage then it is OK

Mabbx

Original Poster:

204 posts

208 months

Monday 19th December 2011
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shaun fulcrum said:
First look at this thread! Dont know why but it has given me an urge to strip my car back the chassis and start again!!! Although that probably won't happen wink

Incredible attention to detail and finish.
Thanks Shaun

Incorrigible

13,668 posts

260 months

Monday 19th December 2011
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Dunno how far you've got with the dash install and wiring, but if you're fitting a data logger you'll probably want to get all the logged parameters onto the dash display (like revs) through the logger initially and then through the serial cable to the dash

I guess you've done all the relevant research anyway smile

ArosaMike

4,192 posts

210 months

Tuesday 20th December 2011
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Really incredibly build quality there. Impressive stuff. Great to see you've gone to the trouble or doing things like having the exhaust Zircotec'd too!

Not sure if any other engineers have looked at this thread, but it really frustrates me to see such terrible mechanical design on kits like this. The suspension geometry looks pretty questionable and the mountings used for the wishbones are just horrendous. I just don't understand how the originators of the kit fail to understand such basic engineering principals! This is absolutely nothing against the work you've done. Genuinely very, very impressed with your fabrication skills. Good work smile

Mabbx

Original Poster:

204 posts

208 months

Tuesday 20th December 2011
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Incorrigible said:
Dunno how far you've got with the dash install and wiring, but if you're fitting a data logger you'll probably want to get all the logged parameters onto the dash display (like revs) through the logger initially and then through the serial cable to the dash

I guess you've done all the relevant research anyway smile
Will be a bit embaressed at this point - electrics is not my thing but I have a good idea of what I want to achieve. Many thanks for giving me the 'heads-up' on this area

Mabbx

Original Poster:

204 posts

208 months

Tuesday 20th December 2011
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ArosaMike said:
Really incredibly build quality there. Impressive stuff. Great to see you've gone to the trouble or doing things like having the exhaust Zircotec'd too!

Not sure if any other engineers have looked at this thread, but it really frustrates me to see such terrible mechanical design on kits like this. The suspension geometry looks pretty questionable and the mountings used for the wishbones are just horrendous. I just don't understand how the originators of the kit fail to understand such basic engineering principals! This is absolutely nothing against the work you've done. Genuinely very, very impressed with your fabrication skills. Good work smile
Many thanks for the kind words on my progress. With regards the suspension geometry, mountings and engineers looking at this build. I am a time served mechanical engineer with Rolls Royce and now a chartered engineer. My career path has taken me now to work within composite engineering - mainley carbon fibre development (hence the panelling) within motorsport including F1 and aerospace. The suspension mounts have been fully load tested by MIRA and the complete chassis and suspension geometry is set and manufactured to a jig. I feel this meets the priciples of design and engineering requirements without over engineering. A lot more than the basics of engineering have been applied to the manufacture and design of this vehicle - hence why I have invested my money in the kit. The designer of this car is a well respected engineer of many vehicle designs and an avid piston heads poster/member so if he spots this thread he may put his point across just to re-assure.

Many thanks

ArosaMike

4,192 posts

210 months

Wednesday 21st December 2011
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I'm sure it's totally safe, there's just a massive lack of correct triangulation and some real howlers when when it comes to load paths in to the chassis. It's hard to tell for sure from the pictures, but there appears to be a great deal of camber change in droop too.

Unlike many on PH, the aim of my post is not to rubbish or be argumentative. I'm just interested to understand why some of the decisions for mountings and chassis triangulation have been made? There's a great deal of good literature out there that describes in great detail, the best practice for designing a race car and/or sports car.

If the designer of the kit does wants to respond, I'd be interested in some justification for some of the things below. I'm not trying to be a spoilsport or a know it all or anything like that. It's just something that's often confused me as an automotive engineer who's had a hand in designing a number of spaceframe cars. I see it a lot on kits (companies like Caterham are not excluded from this as there are some fairly questionable areas on them) and always wonder why some apparently obvious mistakes have been made!









To me, there seems to be a massive lack of any torsional stiffness in the chassis, and there are a lot of places where loads are being fed in to tubes that have no support which will lead to a great deal of compliance. I'd be interested to know what the weight of the chassis on its own is and what it's measured torsional stiffness is in Nm/deg?

Also...with the suspension, there's some liberal use of rod ends in bending. Generally, when it comes to kits, I think it's pretty much OK, as it does at least mean they're easy to adjust, but you also end up with far more mass in the assembly than you would with a weld in spherical. The M20 threaded rod end in my Caterham on the front upper wishbone is still the first thing to bend if it get's clouted. Good in some respects, but it also illustrates how much of a weak point it is, that this bends before two bits of thin walled steel!

Edited by ArosaMike on Wednesday 21st December 09:25

qdos

825 posts

209 months

Wednesday 21st December 2011
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Fascinating stuff but it's very easy to go and pick holes in things though constructive criticism is often helpful. To be fair many kits are not supposed to be bleeding edge vehicles they are cheap and fun. Even top expensive marques cut corners and have been known to go up in smoke.

One of the wonderful things about a kit is that you build it yourself and you are free to do with it what you want, kits are a framework from which you work from and it's fabulous to see people making changes and putting their stamp on their own cars. MEV make very affordable fun machines, some of their owners have put together some really nice looking machines of which this certainly is one of the nicest. RTR also produce some cracking looking examples. At the end of the day the thing with kits is that you have lots of choice and long may that be so. I'm sure there will be a number of people who will take up some of the suggestions and incorporate them into their builds should they want to.

Should you wish to cast your eye over a Deronda you'd be welcome to I think you'll find that more in tune with your outlook but it is a lot more expensive than a Rocket and originally designed for the track but it is available as a kit.

Mabbx

Original Poster:

204 posts

208 months

Wednesday 21st December 2011
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Many thanks for the inputs.

The origional post I felt was more directed to this design as it was posted within my build, but now understand you have thoughts on many other vehicles. It is great to have all areas of industry putting their points of view across, but I dont feel my build thread or any other build thread was/is the place to raise them. I am not designing a chassis but building a car from pre-made chassis design which has had excellent testing results and longevity in useage. Could this proven chassis design be better ? - obviously yes, the same as the Deronda, but you could also say the same in any motorsport or road going car.

Plesee do not feel I am being negative to critisism, but as you have said, this design area could involve many vehicle/kit types, and I do not feel my build thread is the place to air them.

Many thanks

ArosaMike

4,192 posts

210 months

Wednesday 21st December 2011
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qdos said:
One of the wonderful things about a kit is that you build it yourself and you are free to do with it what you want, kits are a framework from which you work from and it's fabulous to see people making changes and putting their stamp on their own cars. MEV make very affordable fun machines, some of their owners have put together some really nice looking machines of which this certainly is one of the nicest. RTR also produce some cracking looking examples. At the end of the day the thing with kits is that you have lots of choice and long may that be so. I'm sure there will be a number of people who will take up some of the suggestions and incorporate them into their builds should they want to.
Absolutely agree. I'm not saying that the kits bad in any way. Far from it. The build quality and welding look superb. It's the fundamental engineering though which I was questioning. A well stressed and triangulated chassis does not cost any more than a badly triangulated one. If anything it's actually cheaper as you can use thinner wall and smaller diameter tubing to take the same loads. Much like the difference between a bridge made of steel gurders and a suspension bridge. Same forces involved, but one is heavy and over engineered, the other is lithe, well thought out and undoubtably cheaper.

In terms of the Deronda.....just because it's more expensive really doesn't mean it's any better. An Aeriel Atom infact has some fairly poor design in it. The guy who has designed the fantastic DP1 sports car did some work on fitting the V8 to the Atom and highlighted a number of rather poor engineering errors:

http://dpcars.net/atom/ak.htm

ArosaMike

4,192 posts

210 months

Wednesday 21st December 2011
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Mabbx said:
Many thanks for the inputs.

The origional post I felt was more directed to this design as it was posted within my build, but now understand you have thoughts on many other vehicles. It is great to have all areas of industry putting their points of view across, but I dont feel my build thread or any other build thread was/is the place to raise them. I am not designing a chassis but building a car from pre-made chassis design which has had excellent testing results and longevity in useage. Could this proven chassis design be better ? - obviously yes, the same as the Deronda, but you could also say the same in any motorsport or road going car.

Plesee do not feel I am being negative to critisism, but as you have said, this design area could involve many vehicle/kit types, and I do not feel my build thread is the place to air them.

Many thanks
Yes...apologies. Very much off topic. Tends to happen somewhat on PH though :P My original point had been more of a musing than an intention to hijack!

As I said....you're level of attention to detail and fabrication skills are fantastic. It's a great feeling finishing and driving a kit car, and I'm sure you'll get stacks of enjoyment out of it. Excellent job smile

Mabbx

Original Poster:

204 posts

208 months

Wednesday 21st December 2011
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Many thanks. Will get some more build pics up soon smile

Mabbx

Original Poster:

204 posts

208 months

Saturday 7th January 2012
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Accelerator cable bracket now fitted to the throttle body. Had to have one made as Jenvey do not make one !!??



Was not happy with the return speed of the cable so added a spring at the pedal end:


Mabbx

Original Poster:

204 posts

208 months

Saturday 7th January 2012
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Made use of the kids x-mas present boxes and mocked-up a header tank:



Finished artical with oil catch tank fitted also:


Mabbx

Original Poster:

204 posts

208 months

Saturday 7th January 2012
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Oil coolers fitted - one for the engine oil, and other for supercharger oil:


Mabbx

Original Poster:

204 posts

208 months

Saturday 7th January 2012
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As this vehicle is transverse and supercharged I have opted to try and get some cold air to the supercharger. Currently trying to find a good route from the inlet through the filter to the supercharger !!


MG CHRIS

9,077 posts

166 months

Saturday 7th January 2012
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Looks like you made some good progress over christmas. Looks excellent. What power output are you expecting when your finished.

Mabbx

Original Poster:

204 posts

208 months

Tuesday 10th January 2012
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MG CHRIS said:
Looks like you made some good progress over christmas. Looks excellent. What power output are you expecting when your finished.
The last engine done to this spec produced 310 Bhp and 270 ftlb of torque (allegedly). I will be happy if it produces anything over 270Bhp with a nice progressive torque figure.