Angle of approach and departure

[MARKS6900]

The initial message was deleted from this topic on 19 February 2012 at 23:04

[Solitude]

good luck with a coherant response to that mate......and respect to anyone who comes up with a "real" answer !!

[adam quantrill]

Put it this way - I went to a vineyard in the Loire valley which had a driveway with a 1 in 2 slope - cue dropping it into 2nd and flooring it all the way up - I almost took off at the top. The incline isn't as important as the curve at the beginning and end.

[400SE Dave]

I tried to do something with a spirit level in the garage to give me a line and I would say approx 20 - 25 degrees for the front and 40 degrees for the back. This is a 400SE ..... obviously!

Anyway, very much a basic, and I do mean basic, estimation so don't build a drive without checking properly

[mrzigazaga]

All i know is i went to see my mum earlier and couldnt park outside because of two inconsiderate fks and had to park on the drive..The ramp is quite steep..Around 3.5ft length ramp, Roughly a 40 degree incline and low and behold i scrape my exhaust on entrance and chipped my newly repaired spoiler on exit...I was pissed off to say the least..I think the wedge is 12 feet long so a 40ft ramp at a 15 degree incline should be ok..Unfortunately maths is not my strong point and its too late in the day for me to make a working miniture model..Ziga

[Solitude]

I rest my case !!

[400SE Dave]

Solitude said:

I rest my case !!

[400SE Dave]

MARKS6900 said:

If you place a long piece of wood up to the front tyre and raise one end until it touches the body work, this gives you the angle of approach, you then measure the length of wood and the height off the ground at the same point to give you the percentage, hope that makes some kind of sense, thanks.

That's pretty much what I did but measured the angle and not the height/length.

[Solitude]

MARKS6900 said:

If you place a long piece of wood up to the front tyre and raise one end until it touches the body work, this gives you the angle of approach, you then measure the length of wood and the height off the ground at the same point to give you the percentage, hope that makes some kind of sense, thanks.

Of course it doesn't !!

[mrzigazaga]

If the height to the garage is 7ft and it has a 40ft long ramp then it will be around 10 degree incline..The main factors are the point where the ramp starts in relation to the flatness of the road or lead up to it and where the top of the ramp meets the flatness of the garage floor..The fact that the wedge is a low sitting car means that by the time the front half is on the ramp the rear is still on the flatter part of the road and once at the top the front half is starting to become lower than the rear end that is still on the ramp..These points are where the exhaust or spoiler run the risk of touching..Do you know anyone with a ramp with such an incline to see if it will be ok?..Ziga

[Solitude]

mrzigazaga said:

If the height to the garage is 7ft and it has a 40ft long ramp then it will be around 10 degree incline..The main factors are the point where the ramp starts in relation to the flatness of the road or lead up to it and where the top of the ramp meets the flatness of the garage floor..The fact that the wedge is a low sitting car means that by the time the front half is on the ramp the rear is still on the flatter part of the road and once at the top the front half is starting to become lower than the rear end that is still on the ramp..These points are where the exhaust or spoiler run the risk of touching..Do you know anyone with a ramp with such an incline to see if it will be ok?..Ziga

You gotta stop smoking that st Mark !!

[Lean Machine]

Mmmm. TVR Wedge + slopes,angles of aproach,angles of departure = disaster. Possible complications = damage to spoiler, damage to exhaust, total loss of car do to dodgy handbrake. My advice, rent a garage on flat surface or rent an earth excavator, dig and build garage down to flat level below house.

Tony TCB.

[mrzigazaga]

..Thats the trouble mate..I HAVE!!..My brain works overtime now whereas before i wouldnt of been asked to even think about such equations..I wont be able to sleep now until i have made a working model and tested it thoroughly!!.............................

[roseytvr]

Nice one! Im with ziga and will probably draw diagrams all night but to work that out you need to know:

1 the angle of approach (it wont be level)
2 Ground clearance at lowest point before front wheels, in between wheels and after rear wheels
3 Length of wheel base, length from middle of front wheel to front of car and midle of rear wheel to the rear of the car.

I dont think the initial incline will be your problem as you could always put down wooden blocks to lift it when you come in and go or even have an initial smaller gradient, I think you are more likely to struggle going over the apex with ground clearance between front and rear wheels - unless you slope the garage floor or drive onto purpose built ramps.

To late for me mate - good luck, but if you post up your dimensions I can give it a bash

[CHJ]

If you have a curve at the bottom of the drive (i.e. gradually increasing incline) that will help with clearance, although it will obviously make it steeper from the middle upwards.

Reversing up might help too?

[400SE Dave]

CHJ said:

Reversing up might help too?

Will it?? I would have thought that would mean you would just catch the front on the road instead of your drive if the angle was wrong wouldn't it????

[mrzigazaga]

Right!!..Ive built a model and tested it..The bottom of the ramp where it meets the road should not be a problem..If it is then use some board to lessen the angle..(As mentioned)..The main problem as seen in the last picture is the top of the ramp where it meets the garage floor but again as suggested if the angle is continued through to the garage then it should be ok..If not then there might be some rubbing of exhaust or possibly chassis..Ziga

The scale is represented by the size of the car so the ramp would be 40ft long and the height would be 7ft and the incline would be 10 degrees...My brain hurts!!

PS:I really should get out more.

[roseytvr]

Over 40 foot you could of course have different inclines at different stages ie work out the max initial incline to get on the drive, steep incline going up and lower incline going over the top, if you are still struggling incline the garage floor and the jobs a good un!

[roseytvr]

http://www.youtube.com/watch?v=N2wUS6kfkRg&fea...

If the link works 1 min 01 sec in shows 14 foot of wedge going up roughly 3 foot incline over roughly 17 foot. This suggests it's doable if you shape the drive as per ramps.

One nice sounding seac also!