Author Topic: Alvis Firebird Special  (Read 1009 times)

Ian L

  • Forum user
  • Posts: 126
  • Location: Somerset

Badges: (View All)
CKGB Member
Alvis Firebird Special
« on: 11 Feb 23, 06:58 pm »
Having been dipping in and out of the CycleKarts GB site for a few months, I spotted that there was a builders meeting which answered many of my (initial) questions and kickstarted by build.

Inspiration Car
I have always liked the Alvis and particularly the Firebird which I have chosen as my inspiration. My Grandfather had a Firebird that I can just remember as a child, he always joked the folding roof was made from elephant hide - different times.

Like lots of cars of the period the body was coach built and the same was true of the specials - so lots of choice.

Dimensions
Having chosen my inspiration car it was time to make it fit in the to the Cyclekart format - (I found lots if good advice on the forum) The Alvis is scales longer than the Stevenson format and having taken on the need to get my 6 ft 3in frame in to the car so stretching and shrinking was needed. But I think I now have something that will work and have made some full size layouts.

Full Size Mockup
As many before I decided that a full-size mockup was key, this is still a work in progress as I continue to collect part for the build and tweak the sizes.



Share on Facebook Share on Twitter


synthpunk

  • Forum user
  • Posts: 294
  • I build things and make alot of noise
  • Location: EG, west sussex

Badges: (View All)
CKGB Member
Re: Alvis Firebird Special
« Reply #1 on: 12 Feb 23, 10:18 am »
Excellent work! A great start! 
Particularly impressed with the large scale drawing and mock-up. When I designed my Riley I made smaller drawings and a 1:6 scale model. There were a couple things I didn’t sort out in advance because I didn’t understand how it all fitted together, namely the engine bay and steering. So I left some space and pressed on. THe engine bay turned out to be relatively straightforward, but the steering has been biting me on the bum ever since. Basically my pretty, swoopy angled chassis rails get in the way of everything I’ve tried so far. No matter how I angle the shaft, or pitman arm, or where or how I position it, it seems like something binds or interferes somewhere. I think I’ve worked it out now, but it has meant using a steering rack, which obviously has cost money, delayed everything massively, and has added weight and complexity. Oops.
So yeah, well done on the prior planning! Cant wait to see it in the flesh.
Cheers!
Rich

RhysN

  • Forum user
  • Posts: 1093
  • Location: Tamworth

Badges: (View All)
CKGB Member
Re: Alvis Firebird Special
« Reply #2 on: 12 Feb 23, 10:37 am »
Looking god and always great to mock it up. Can I suggest you check the seat to dashboard for yourself, getting in and most important out? It looks somewhat minimal from what you have shown.
Great advice from Synthpunk, listen to what he said (and I suspect one of the many phone calls :) )
We must avoid torturing our brains with false problems, it occupies but it can annoy. In jest!

Ian L

  • Forum user
  • Posts: 126
  • Location: Somerset

Badges: (View All)
CKGB Member
Re: Alvis Firebird Special
« Reply #3 on: 13 Feb 23, 10:47 am »
Rich, Rhys, Many thanks for the comments and encouragement.

I had always thought a good set of full-size drawings and a quality mock-up would be worth the effort - (£4 well invested on a roll of lining paper!) I intend to improve it as I go with some aspects more like a twin to the CycleKart, such that I can use them as templates (eg front hangers) and or soft jigs for the chassis.

I have increased the size of the cockpit since posting, as you suggested a bit tight, I still have a bit to play with between the dash and the scuttle. Once you get over that you are not making an exact replica and you need to fit in to the car with some design licence it gets easier! I have a couple of reference photos gridded up so the front end should still be reasonably accurate.

I have a front view drawn that with some cradles between the axle (Gemini) and the spring lifts the location for the track rod end to be inline with the top  of the chassis - mockup will confirm if this works - if i need some more clearance I can increase the carrier. Or if push comes to shove I can cut down the chassis to say 50mm which will give plenty of clearance - trying to avoid this!

Still collecting bits, and will order some box section when I have the mock up progressed a little further.

Happy building!

StefanN

  • Administrator
  • *****
  • Posts: 1052
  • Location: Bagshot, Surrey, United Kingdom
  • CKGB Committee: Yes

Badges: (View All)
CKGB Committee CKGB Member
Re: Alvis Firebird Special
« Reply #4 on: 13 Feb 23, 11:14 am »
Hi Ian,

Nice progress!

Re cockpit space,  I measured the horizontal distance between the centre of the steering wheel and the seat back on a number of cyclekarts and they ranged from 47cm to 51.5cm.   Mocking it up is definitely a good idea too.


Ian L

  • Forum user
  • Posts: 126
  • Location: Somerset

Badges: (View All)
CKGB Member
Re: Alvis Firebird Special
« Reply #5 on: 13 Feb 23, 01:18 pm »
Thanks Stefan,

Useful nugget my first mockup was closer to your dimensions but tight, then I did the full size layout.

I scaled the Stevenson diagram and came up with something more like 675mm but that is front of the dash to seat back.

If I take off 100mm for a gap around the steering wheel and say 50mm for the seat itself Im more in the range of your dimensions.

Will let you know what I end up with!

Ian

StefanN

  • Administrator
  • *****
  • Posts: 1052
  • Location: Bagshot, Surrey, United Kingdom
  • CKGB Committee: Yes

Badges: (View All)
CKGB Committee CKGB Member
Re: Alvis Firebird Special
« Reply #6 on: 13 Feb 23, 05:34 pm »
More is good

Ian L

  • Forum user
  • Posts: 126
  • Location: Somerset

Badges: (View All)
CKGB Member
Re: Alvis Firebird Special
« Reply #7 on: 19 Feb 23, 09:00 pm »
Soft Tooling / Mockup Mk2

Following on from last week I have revamped the mockup into soft tooling for the chassis. This also makes the mockup more accurate, I plan to make the body frames and use these for tooling as well, but need to decide on the body lines, more on this below.

I now have enough room to get in and out of the cockpit! I do need to try with the steering wheel in position (If you are using a removable steering wheel BoS can you please send me a link) Key to this is a lot slimmer portal for the scuttle area and pushing the seat base back, and hence more upright 22.5deg v’s the original 30deg, with this I can now get my knees out.

The Firebird bodywork extends beyond the chassis lines, Im contemplating if to try and replicate this to some extent, as it is a feature of the car or simplify things and run the bodywork along the chassis. The mid lines are also starting to take shape around the cockpit,  think I will go for ply bodywork as my first CK - any words of wisdom on this would help me.

I have added the front axle to the mockup and this confirms that there is clearance above the chassis lines to the steering post. I will add this to the mockup next, which will allow me to set out the steering column bearings as well. Space looks to be limited in this area so need to check on any clashes with the peddle box - How are you driving your CK, straight or bent legs? This would impact the peddle box location.

At the other end I need to workout how to package the engine, but hopefully solutions will present themselves when I offer it up to the mockup.

Ian L

  • Forum user
  • Posts: 126
  • Location: Somerset

Badges: (View All)
CKGB Member
Re: Alvis Firebird Special
« Reply #8 on: 12 Mar 23, 05:28 pm »
Making Little Bits

Last week I was loaned a small lathe, which had been out of use for many years so needed some recommissioning, new belts, freeing up some rusted bits, getting a set of 6mm tools.

This week I have had it up and running making some small pieces for the steering, and the peddle box. Getting some more of those latent skills back!

Proving very handy for drilling and reaming spacers, lots more to be made!

Suspension Hangers and Axle Brackets

Also on the list this week has been the first of the front suspension hangers, I made a plywood template having roughed out the plate this is then used this to get the finished shape, hopefully it will last for three more!

They need a 6mm joggle which I made with a couple of hex keys in a vice, handy as you can use the key for the desired joggle.

Fabricated a couple of axle supports, which went ok, may need some fine tuning when bolted up.

Chassis Frame

Last some progress on the chassis frame, springs arrived this week so I have been able to finalise dimensions, allowed 10mm for spring compression.

First angles are rough cut, soft tooling is doing its job, i plan to run the angle grinder down the joint to cut both sides and achieve a close fit.

Thinking I will add some backing plates, will see how it develops.


Chris L

  • Forum user
  • Posts: 301
  • Location: Taunton Somerset

Badges: (View All)
CKGB Committee CKGB Member
Re: Alvis Firebird Special
« Reply #9 on: 13 Mar 23, 12:26 pm »
Nice One Ian.......particularly liking that Axle support ....Well done

Ian L

  • Forum user
  • Posts: 126
  • Location: Somerset

Badges: (View All)
CKGB Member
Re: Alvis Firebird Special
« Reply #10 on: 27 Mar 23, 08:32 pm »
Chassis and Suspension LHS

I have been continuing to work on the front end of the CK.

I have shaped the chassis and made the front hangers and swinging suspension brackets. I have also made the first joint to the angle section of the chassis - marking out and cutting plus a mm or so and then cutting through both faces with the angle grinder made a nice joint.

Welding skills are improving, all holes are drilled and reamed and with the aid of the fixture the trial fit is looking good - if I say so myself!

On to the RHS next, but this is aided with the knowledge from the LHS build and the parts can be used as a template. Im sure there will be some further fettling once i have both sides, I will add some spacer plates for the rear hangers to improve the bearing area, before painting individual parts and final assembly.

Glynn

  • Forum user
  • Posts: 103
  • Location: Somerset UK

Badges: (View All)
CKGB Member
Re: Alvis Firebird Special
« Reply #11 on: 29 Mar 23, 10:36 am »
Looking great Ian, you have been busy!

Ian L

  • Forum user
  • Posts: 126
  • Location: Somerset

Badges: (View All)
CKGB Member
Re: Alvis Firebird Special
« Reply #12 on: 15 Apr 23, 09:54 pm »
Made some progress on the chassis yesterday and today.

Chassis

I have made the RH suspension hangers and fitted these to the chassis. Tooling did its job in keeping all aligned for drilling and reaming before loose assembly.

I have also cut to length and formed the joints and made up all the joint plates, these keep things aligned ready for welding.

Joints all aligned cleaned and clamped. Next stage welding up……

jim

  • Forum user
  • Posts: 631
  • Location: northants

Badges: (View All)
CKGB Member
Re: Alvis Firebird Special
« Reply #13 on: 16 Apr 23, 07:09 am »
Nice work Ian, That's going to be a good looking vintage style chassis.
If you can drive round corners, you're not going fast enough.

Ian L

  • Forum user
  • Posts: 126
  • Location: Somerset

Badges: (View All)
CKGB Member
Re: Alvis Firebird Special
« Reply #14 on: 16 Apr 23, 07:31 pm »
Thanks Jim, I realised when laying out the mockup that the build is all a compromise, while trying to capture the spirit of the inspiration car and package it into CycleKart dimensions. The Alvis has a distinctive cranked chassis and front suspension hangers so hopefully as things come together so will ‘the look’. Cheers. Ian