Building on Lotus 7 principles

[Iain Hall]

Hi Guys I have been lurking here for a while and reading as much of the archive as I can because I have wanted to build a teardrop for a long time and now the time has come to actually do the deed and I have begun by building my chassis/
First thigh a bit of my background I have built my own Lotus seven type sports car https://iainseven.wordpress.com/ so I am very familiar with tubular space frames so it occurred to me that a teardrop is an ideal candidate for the use of a space frame in its construction if you can roll the tube into appropriate arcs To this end I am making a tube roller which I expect to be fully functional by the end of the week.

The plan is to have something that is tow-able by my daily driver (a fwd Nissan) and the vintage Morris I am building so I want to keep the weight down and the traditional construction methods seem to result in rather heavy Tears
No I will see If I can post some pictures

The plan is to partially recess wheels into the body because I want to make the internal space to be wide enough for a double bed but keep the overall width down do that I won't need any special mirrors for the cars.

The profile I am going for will be something like the very earliest designs from the 1947 Mecanix trailer for two but shortened by two feet so that standard 8 x4 sheets of 3mm ply can be used for lining and cladding The plan is to put a layer of fiberglass cloth and epoxy on the outside so that the wood grain of the ply can be seen the wall cavities will be filled with polystyrene sheet for insulation and to support the ply/epoxy skin/lining. i live in Queensland Australia and we have a very mild climate most of the time so I don't need to go overboard with insulation to be comfortable.
The floor will probably be no more than 10mm ply with Polystyrene glued between the framing under it.
For wheels on mine I am using 1946 Morris 8 wheels and hubs which are 17" and take a 130/90 motorcycle tire

As if that is not enough It looks like I will me making two other space frames because My brother and his mate both want me to build ones for them The former will help me fix some rot on my house in exchange and the latter will be offering cold hard cash which will help offset the costs of my build My brother wants one to tow behind his new MGB and his mate has Morris Minor ute

[GuitarPhotog]

I have a 1948 teardrop built to the Teardrop for Two plans. Do yourself a favor and put a real window in each of the doors. And put in two doors. Even for a solo camper, having only one door is a PITA.

On a side note, I coveted my friend's Super 7 all those years ago

<Chas>

[Iain Hall]

I totally agree with you about having two doors I have camped with my wife the need to crawl over your partner to answer the midnight call of nature is not the way to have a peaceful relationship I will of course NOT have that compartment at the front and my kitchenette will be a bit smaller length wise but I will be a bit wider so will get a bit back that way.

[KennethW]

I would make the bottom of the door lower so when you are setting in the door way your legs are not held up by the bottom of the door opening. Also make the door tall enough to sit in. i like plastic bins instead of drawers. With plastic bins you can set them on the bed and go thru them easily.

[Iain Hall]

I would make the bottom of the door lower so when you are setting in the door way your legs are not held up by the bottom of the door opening. Also make the door tall enough to sit in. i like plastic bins instead of drawers. With plastic bins you can set them on the bed and go thru them easily.

Yeah my brother was on the phone today saying the same thing about having the bottom of the door lower and I will do that, I will probably just double up the 25x25 rail and take the door from there I plant to make the doors with arched tops for the look of them and I see no reason not to make them go to with in say 4 inches of the roof frame and I have wasted no time getting my chassis sitting on its wheels for the first time

I am not going to go for a complicated kitchen at all and I will look at using all sorts of ready made ideas like plastic bins and trays

[KCStudly]

Welcome! The seven is a neat project; I spent a bit of time going thru your blog and enjoyed that, thanks for sharing.

I realize that you are early in your planning, but you will want to take a careful look at your side door placement and size. The rule of thumb that is recommended by experienced users of TD's is to have the door sill about half the mattress height. That way when you are sitting in the doorway the sill doesn't dig into the backs of your legs and getting in and out is easier. A few people like to have the door run all the way past the opening so that they can sweep out under the mattress, but most find it easier to seal with a full flange.

Your front to rear placement looks to be pretty close, but perhaps a bit forward. The consensus seems to be that you want to be able to "sit and spin". In other words, you want to be able to sit down in the doorway, roll back while pulling your knees and feet up, then rotate into your sleeping position without a lot of shifting or shimmying into your sleeping position. The only thing you need to look out for is to make sure that your door trim clears your fender (wheel guard).

One more thing, I like the idea you have for keeping the drawers secure while traveling, but you may want to do a mock-up in cardboard or something, including the ceiling, to make sure that you like the ergonomics of having to look and reach over the drawer front. Many people prefer sliders or doors that flip up or to the side so as not to block easy access. What you show looks like it might be okay, but it would be good to be sure it is as convenient as expected before going to the trouble of building it. I'm just thinking that it might be a little tight to kneel in front of the drawer with head leaning over to look down in and then reaching up and over to get something out. I would be happy to be wrong on this.

Oops, I see I wasn't the only one...

[Iain Hall]

Welcome! The seven is a neat project; I spent a bit of time going thru your blog and enjoyed that, thanks for sharing.

Yeah I love my Seven and it was a very big deal to build and get it licensed

I realize that you are early in your planning, but you will want to take a careful look at your side door placement and size. The rule of thumb that is recommended by experienced users of TD's is to have the door sill about half the mattress height. That way when you are sitting in the doorway the sill doesn't dig into the backs of your legs and getting in and out is easier. A few people like to have the door run all the way past the opening so that they can sweep out under the mattress, but most find it easier to seal with a full flange.

I am going to make the door bigger (with a lower sil) than the schematic I posted because I do appreciate the value of being able to get in and out easily when necessary I am really only using that schematic as a rough guide so that I can get the basic shape right . Mostly I'm making it up as I go along which may well horrify many here who are very keen planers of every operation making their Tears. I am an artist used to "winging it" and designing as I go Today I got the parts I need to finish making my tube roller and the curves I can make will very much determine the final profile

Your front to rear placement looks to be pretty close, but perhaps a bit forward. The consensus seems to be that you want to be able to "sit and spin". In other words, you want to be able to sit down in the doorway, roll back while pulling your knees and feet up, then rotate into your sleeping position without a lot of shifting or shimmying into your sleeping position. The only thing you need to look out for is to make sure that your door trim clears your fender (wheel guard).

The axle location was worked out from looking at lots of builds which generally have the front edge of the wheel just behind the center-line and that center line is precisely where the front mounts for the springs are, My body will also be wider than the inside of the wheel covers by about three inches each side

One more thing, I like the idea you have for keeping the drawers secure while traveling, but you may want to do a mock-up in cardboard or something, including the ceiling, to make sure that you like the ergonomics of having to look and reach over the drawer front. Many people prefer sliders or doors that flip up or to the side so as not to block easy access. What you show looks like it might be okay, but it would be good to be sure it is as convenient as expected before going to the trouble of building it. I'm just thinking that it might be a little tight to kneel in front of the drawer with head leaning over to look down in and then reaching up and over to get something out. I would be happy to be wrong on this.

I don't think That my interior will be anything like that schematic, I won't have that front compartment at all and My storage is more likely to be something like the basic compartment with sliders either side of a central TV screen I I can end up with about a back pack size space on each side I will be more than happy

[Iain Hall]

Spent the day building my tube roller so I am rather naturally quite exhausted now

It seems to work well enough but I will give it a workout tomorrow after I have got myself enough tube to finish the profiles
Here is the result of my first attempt to roll a tube

[KCStudly]

That'll work.

[Iain Hall]

this is the profile I am looking at There will be a slope on the flat part of the roof but this picture does not show it well because it was taken with my phone and has a level of foreshortening

[Iain Hall]

Well i have had a very productive day today and I think that I have reached a significant milestone because I now have my side profiles both made and sitting on the chassis


Until you build it it its hard to really have a handle on the size that your tear will be in the flesh. So I am well chuffed to see mine in the workshop looking so good.

Of course the profiles are not in their proper place as yet because the bottom rail hits the wheel hub when I try to put it in the right spot and I will have to make a temporary "notch" in that rail so I can place the profile where it belongs
Finally here is a view from the front which shows that I have managed to get it to have some good lines

[Iain Hall]

Been busy again today I have welded the side frames onto the chassis and now I'm onto fixing the Guards (bought from Ebay) because they are simply not long enough, my solution is to fold up some steel and weld it onto the back which gives them a tear shape when in situ

After cutting its a bit time consuming but they can be welded up with the mig

[Iain Hall]

Well I think it now really looks like something really nice!



What I am finding most pleasing though is just how much space there will be inside the cabin Having thin walls will pay off with more usable space

[Iain Hall]

I've been going great guns today, I got all of the spars between the profiles in before breakfast then I worked on the opening for the Skylight (the last picture here and it was a bit tricky because the point where it sits Is where the sharper curve of the front arc changes to the more subtle curve of the "flat" part of the roof. I have also managed to weld up one door frame and cut out the parts for the other side. My doors will be 650mm wide and 950mm high in the center of the arched tops. I was considering taking the doors to floor level but in the end I decided that a bit of a lip would be better aesthetically and set the rail to be just 25mm above the existing profile base This is high enough to allow floor sheeting out to the edge But low enough to give a good sized opening.

[KCStudly]

Good work.

Personally, I would go wider on the doors. At just over 25-1/2 inches... less if adding an inside flange for an inner seal... unless you are particularly agile, you may have a hard time swinging your knees and feet in.

The older I get the less I bend.