[CK 187]

photo of the current supermono swing arm

Looks good.

 

[TeeJ]

it looks rock solid (steel tube btw) must b super rigid. Have you seen how low the rear sets are?? it feels horrible to sit on and the shock fouls the intake a bit, hopefully we will get our hands on the dissertation and see why they picked a cantilever, doesnt seem like there is much angle on it so i duno how progressive it is

 

[CK 187]

it looks rock solid (steel tube btw) must b super rigid. Have you seen how low the rear sets are?? it feels horrible to sit on and the shock fouls the intake a bit, hopefully we will get our hands on the dissertation and see why they picked a cantilever, doesnt seem like there is much angle on it so i duno how progressive it is

Was wondering that myself as i looked at that last pic

 

[TeeJ]

Yeh its a little strange coz on first impression its like wow they built a proper racing bike but then wen u question design its a bit odd. Apparently only one person designed the chassis out the group, so good effort for one person definately but it can definately be improved.

Heres an interesting fact: the supermono weighs 138kg

The lightest formula student car ever made at the uni was 122kg

 

[Smoker]

 

[Ironspade]

Don't get me wrong I'm all for a change of pace and doing things a little different but this is like reinventing the wheel. I've read about these Hossack frame designs in older chassis design books. Do you really gain that much in the way of building like this or are you guys just trying to prove a point? It seams to me if your trying to win races, take a proven design, push all the limits of what you can get away with and ride the thing like you ass depended on it! It totally my opinion but if these Hossack frame designs were so good, how come no one has built any in years?

Just my 2 cents worth. Later Travis

 

[Smoker]

Don't get me wrong I'm all for a change of pace and doing things a little different but this is like reinventing the wheel.

I think the purpose of this build is to learn something about motorcycle engineering, not to find the easiest way to win races.

 

[shift1313]

and they arent building a hossack front anymore. Just a super mono frame.

 

[Bob138]

Don't get me wrong I'm all for a change of pace and doing things a little different but this is like reinventing the wheel. I've read about these Hossack frame designs in older chassis design books. Do you really gain that much in the way of building like this or are you guys just trying to prove a point? It seams to me if your trying to win races, take a proven design, push all the limits of what you can get away with and ride the thing like you ass depended on it! It totally my opinion but if these Hossack frame designs were so good, how come no one has built any in years?

Just my 2 cents worth. Later Travis

Hossack front ends are used on some beemers. Correct me if I'm wrong here, this is what I remember; What you gain is a single point of shock absorbtion compared to two. Conventional forks can create stiction when the two tubes compress at different rates and by nature they negatively adjust rake, causing a twitchy bike to become even twitcher mid turn.

Hossack front ends acutally increase rake when compressing mid turn which can aid stability.

The only negative point I can think of is single point of failure in a single front shock, though I assume that seeing as we get by fine with 1 shock in the rear it would be ok. BUT, I don't know if the forces exerted on the front end would be more fatiguing on the front shock. Think of high speed braking ect. I'm sure shift can correct any errors and supply the math to better explain.

Bob

 

[shift1313]

Here is some info/history from Norman Hossack.

http://www.hossack-design.co.uk/php/page.php?p=4

BMW would not work with hossack on front end design so their setup is a little different. There were some hossack bmw setups but i dont know that anything currently in use is "hossack". The hossack setup completely removes the shock load from the steering stem and allows you to orient the shock in many different ways. Because the shock is only functioning as a shock and not a structural member, there shouldnt be any failure issues. The front end is basically like upper/lower A arm setup in a car except the steering axis needs special consideration where a car has some caster to it as well as camber.

Depending on the upper/lower link length, pivot location and angles you can get a large variation of rake/trail changes during bump. Here is a good picture of one of the early designs and its shock location.

 

[TeeJ]

hey guys,
Sorry i havent been on and posted in a while ive had a shit load of work to do. Got some free time this evening so here i am!

We have calculated the CoG of the bike and ill stick the photos on now. Its 465mm (18.3") with no fuel so quite low really. The picture shows you where it is its along the yellow mark right about where the exhaust goes from 2 into 1.

As for the engineering i think we will be doing some ADAMS modelling for the dynamic side of things. Dont really know what this is going to end up like because if we try and simulate a corner then the rider has to roll and move around the bike. I think doing a steady curve tho is fairly do-able. Jus looking at doing the modellin in ADAMS or importing as an IGES file. Neither are particularly easy. Other than that we are investigating SAE papers tomorrow we have about 20 or so and then we will probably get some more so the designs hotting up a bit now.

Also i will hopefully have the CAD model of the old supermono so ill scrnsht that and stick it up on here. Also we wil be doin the FEA on the old bike as well so thers gona be some nice colourful photos up on here, or should i spell it colorful? lol

 

[TeeJ]

 

[TeeJ]

dude what is that and are ther more pics??

 

[TeeJ]

Don't get me wrong I'm all for a change of pace and doing things a little different but this is like reinventing the wheel. I've read about these Hossack frame designs in older chassis design books. Do you really gain that much in the way of building like this or are you guys just trying to prove a point? It seams to me if your trying to win races, take a proven design, push all the limits of what you can get away with and ride the thing like you ass depended on it! It totally my opinion but if these Hossack frame designs were so good, how come no one has built any in years?

Just my 2 cents worth. Later Travis

yeh i appreciate what your sayin man and your right. But its wrong to accept what you hear as fact. Always find out for yourself. Question everything.

About the hossack tho its a good idea but i think its let down by bump steer risk and the fact that theres gona b a loss of feel with all the linkages and stuff. As a suspension system it kicks the telescopics ass. In engineerin terms telescopic forks are shit but they work because u get good feel and theyr cheapish and look neat and still do the job. In racing you want as much feel as you can get. Its gona b a lot different to master a hossack in racing. bare in mind no-one used telescopics on old bikes coz they were so bad everyone stuck with girder or lead/trailin link.

You are right tho thats what people are doing in motoGP. Everyone knows telescopics really well, if you wana win it is probably easiest to stik with convention.

I wanted to do a hossack coz its somethin different and not many folk have tried it in a racing environment, even if you find out its a shit thing to race with its still a valid engineering result, but like shift sed its a bit unfeasible and so we are stickin with chassis and swing arm design and goin for broke

 

[TeeJ]

Hossack front ends are used on some beemers. Correct me if I'm wrong here, this is what I remember; What you gain is a single point of shock absorbtion compared to two. Conventional forks can create stiction when the two tubes compress at different rates and by nature they negatively adjust rake, causing a twitchy bike to become even twitcher mid turn.

Hossack front ends acutally increase rake when compressing mid turn which can aid stability.

The only negative point I can think of is single point of failure in a single front shock, though I assume that seeing as we get by fine with 1 shock in the rear it would be ok. BUT, I don't know if the forces exerted on the front end would be more fatiguing on the front shock. Think of high speed braking ect. I'm sure shift can correct any errors and supply the math to better explain.

Bob

pretty spot on mate from what i know. you can adjust the dive properties with hossack, and yeh each telescopic works individually except for the bracing of the axle. I would definately like to try a hossack frame out of curiousity, must be an interesting thing to have a go at. I think the idea was to separate steering and suspension unlike on a tele which does both.

 

[Smoker]

dude what is that and are ther more pics??

Custom frame for an RD/RZ350 engine.

 

[TeeJ]

that looks awesome, i wana see that on the road!!