Drypod 2

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If anyone was wondering about the progress on the Drypod - there isn't any. I was unhappy at the flimsy nature of the body and any measures to correct it were not likely to leave me with anything I'd be happy with. After much pondering and procrastination I have determined a new direction for an attempt:-





Visually similar but a completely different manufacturing path to the Mk1. The chassis come lower body is to be plywood with the blue lines with red dots being horizontal panels and held either side by the solid blue panel. Holes will need to be made in relevant places to keep the weight down and a minimum of structural ply will be used with correx bridging any gaps to keep weather out. The door on the original was a major headache being extremely flimsy and difficult to get it to hold shape. The new version will have no door and will hinge up at the front. The upper body will go somewhat high tech and be made from honeycomb Thermhex panels which are exceedingly strong and light. I've considered Thermhex for the chassis, and whilst it's certainly up to the job the ability to join it into a cohesive chassis is simply not there without creating a rigid steel perimeter structure. The top bodywork is not structural and aluminium angle tabs can join it together. Sitting atop the Thermhex body is a polycarbonate set of windows though I'll use Thermhex for the back and top as it's lighter. The upper half will slide just outside the lower half to shed rain outside rather than in. A bead of silicone can be run all around the inside joins and I hope / expect this will be more water tight than the previous failure would have been. Again I'd like to make a curved screen as it adds very little extra weight but looks so much more professional. As to expected weight - this is much harder to guestimate. I think the wooden chassis is going to hit 12kg itself but the Thermhex will weigh less than 1.5kg - it's about a seventh the weight of wood. There'll be 5kg of 2mm polycarbonate and 3kg of channel to run the side windows in. There'll be all the usuall extras such as wheels and fasteners too. It be my first monocoque structure with various metal bits bolted through so there's much to learn on the way. Conveniently the wooden structure all comes from a single piece of 8x4 and I'm thinking 12mm will do rather than 18mm.
I've already noticed that the body to steering column bracer showing in the diagrams will have to go in favour of a floor mounted one or more likely I'll go with side levers by the seat.
 
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Hi there

Not sure where your seat lies ? in this ?

Have you seen this ? Kingcycle bubble & Squeak has a clever Cellite Board chassis
 
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I know my CAD work is exceptionally basic but the seat is that seaty looking white line thing mounted on the plywood platform raised several inches off the floor. I have to raise the seat off the floor to see over the front which has to clear the pedals. Most velomobiles leave just a head or less poking out but I want better visibility than that as this machine will operate in traffic. I'd definitely describe this as an enclosed trike rather than a velomobile. For the same reasons I can't recline the seat too much, though I've done so more than the Mk1. Equally I don't want a very laid back and low racer. I want something that is easily spotted by other road users.

The link doesn't work Paul but I believe I found it. Cellite is a similar material to Thermhex but of a design using differing materials sandwiched together. Thermhex is all one type of plastic. Both would be equally useful for this but the advantage of Thermhex to me is it's available down the road at Sheffield. Hats off to them, the people in that link have gone to quite some measures to build their machine by making large ovens and complex formers plus vaccuum forming carbon which is way more than I'm looking at. This machine will be screw, bolt and glue with minimal welded parts for wheel mounting and such. I know the Thermhex can be moulded to very complex high strength shapes as the automotive industry does so for such things as car boot (trunk) lining panels. Maybe others would go the route of making ovens and formers but it's more work and expense than I feel is justified.
 
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Nice. I will throw my 2 cents in on this. I had tried something similar first on my Warrior trike. The first attempt was similar to your design in that it featured the front part of the body tilting up for access. It worked but 2 problems arose. The roads here like many places are in poor repair and with the pounding plus the pivot point being at the front end and a good deal of weight on the front of the trike the thin wall square tube used for the frame actually bent downwards and I found my feet striking the ground on the downwards stroke of the pedals when going over bumps. The front frame was cut, rebent and welded to fix that. Next I tried a different style of body with one door on the right side. It was a bit better but after a friend remarked it looked like a coffin plus the fact it was quite form fitting that one got scrapped as well. So a change of plan was in order. From tadpole to delta style using Brads Aurora plans as an inspiration. First thing, heavier steel frame, in this case 1/8" wall tube. No more bending. Plus a higher seating position. Fully enclosed sans floor. Fairly large flat windscreen with smaller windows on the sides and rear. And not form fitting, I was not looking for a claustrophobic feeling this time. Then it needed a small 12 v battery to power a LED headlight, rear running light and 4 small LED penny lights as turn signals. This one worked well, it got tested in a heavy rainfall, result was I was nice and dry. Then it got used at a rough temp of minus 20 Celcius, result was success again, the biggest issue was having the correct clothing choices. The biggest error here was my tire choice, I had taken a liking to the fat tire style thinking that would be best for snow. Turned out it did work but anything deeper than a few inches was impassable depending on the condition of the snow. Fresh fluffy snow was easy, wind driven compacted snow not so much. Plus the fat tires are quite soft and wear fairly quickly. Your comment on visibility is exactly right, the downwards slope of the front end is a good thing. My enclosed trike is due for a major makeover. The fat tires will be set aside in favor of a more traditional bike wheel and since I am a fan of bike systems I hope to add a front hub motor to make the trike a 2wd drive, 1 wheel in front and 1 in back. Anyway, good luck with your design, I look forward to seeing it progress.
 
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1/8" is fairly chunky stuff but the Warrior has a long boom. The end of it is a long way from any bracing and even a modest weight on the end is going to leverage a large effect. Everything above the chassis on this ought to weigh 12kg or so and the wood will transfer that throughout the sides where it's strongest other than when in the open position where it'll all be on the front. I could loose 12kg from my waist and still be fat (I am trying!) so I'm more concerned with my lard on the chassis than the bodywork's. I have considered fatties (tyres not me) but think I'm going to go with the skinnies from the Mk1. If it snows (maybe a couple of days a year here) this'll stay in the garage. I think the lower weight of the skinnies will be more use than the shock absorption of the fatties. I'm not currently sure if I'll add a motor here. I do have one but it's in use on a two wheeler monster truck with very long suspension at the moment. I've left the under seat area for battery and controller etc should I fit one. I generally hate working with wood as it never behaves the same twice like good old steel but here I think it's a better option than steel making a lower body and chassis at the same time.
 
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Previous failure? You're being too hard on yourself Popshot. You have successfully proved that your previous design was not going to work. It's just part of the design process. Looks like you have an interesting concept.

Something I considered at some time for "contouring" coreflute/coroplast/[insert your own here] plastic. To join two edges together, insert short plastic straws in the tubes of the coreflute to keep the edges aligned, bent the two pieces to the required angle and glue in place. I have yet to get to the point where I can try it.
 
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We always learn more from a failure than a success so they end up being more important in the long term. For instance I also learned that 40x20x1.5mm steel is fine for a SWB trike chassis where the rider sits near the front axle as per a Warrior but moving the front wheels forward as per this and the Mk1 it's simply not butch enough in the same design configuration (for my weight anyway). Many folk want to hide their failures as though they don't exist and only post about their successes but hopefully others can learn from the Mk1 particularly so if this Mk2 is more successful.

Some design tweeks. The main ones are I raised and reclined the seat some more and changed to a GRP recumbent seat (that bit more in my mind that the drawings). As a result I shortened the canopy which will save weight as the polycarbonate is relatively heavy. The chassis is tweeked as a result and to provide an overlap to the body plus to add a little more wood round the front suspension. Using the GRP seat saves 2.5 kg. I've also shortened the nose to loose the wasted space and bring the body back in proportion due to the shortened canopy.



 
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About failure: Embrace it, learn from it, and keep moving forward. I make a point on my own blog to talk about my failures and my successes for this very reason. There's far too much stuff online that looks like "I did this thing and it worked on the first try!" because they leave out all the times they failed, and this makes people feel like they're not smart or good enough to do the same thing- but they are.
 
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I would have thought 6mm plywood is sufficient if you can cut some strips from it and glue them @ 90' on the longer runs to provide ribs/lips ?

Seen this :- Broncis

Foam , tilts forward light etc

 
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Unfortunately all but one of the pictures has died Paul. If you have any I'd appreciate you posting them. I currently can't see how I'd get away with 6mm but if you've got anything to convince me otherwise that'd be great.
 
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I do have some Broncis pictures but nothing showing the pivot.

This is all plywood ?

carcle



I would have though the Lynx would be a better bet for you ? just make it taller and shorter ?

Lynx sadly Photobucket killed these pictures , however there are some good video at the bottom ?

have you seen any of the french cyclecar stuff ?
5 page plans ?



more stuff here :- Plycar
 
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The Lynx has a metal chassis so the plywood is all non-structural.

The Carcle is very interesting in that their main load bearing areas appear to be 12mm ply as my expectation. It's difficult to tell but it's certainly no thinner. It has large holes cut in which are larger than I am thinking of though it also uses 12mm in non-structural roles too such as the doors. It does offer some confidence in leaning your arm out of them without fear of breaking it though as per the picture. Using plywood all over has it at 76kg which if de-electrified would be about 60kg. I'm still hoping to come in sub 50kg but time will tell if that's just wishful thinking from a wood chassis novice. I doubt many people over estimate their projected weight on something like this. It's certainly a handsome design and I'm impressed. I wonder if Chris Barrie knows he has a Slovak doppelgänger?

I've seen a few such plans as those with most seeming to have no examples left if any were ever built. They were designed at a time when the average chap weighed 3 stone less than today too! I have doubts about the viability of some of them and all of them are somewhat scant on important details. Brad would take 100 pages to detail something like that in a plan not 5.

I believe it is possible to go below 12mm but that would require some quite intricate box sections to produce the strength needed. My wood skills are likely to have my backside falling through such a structure should I attempt that and pulling the resultant splinters out of my fundament is not a prospect anyone should find appealing! Such a complex amount of boxing would be nearer a wooden plane in construction complexity requiring many days or more likely weeks of work to create. The design I'm currently favouring would be a days work or so to cut and assemble the basic chassis. Intricate boxing is certainly a better way and will give a superior product. Maybe a consideration for a Drypod 3 if number 2 ever lives.
 
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this subject has come up at the right time.
I am considering enclosing my Street Fox for winter riding around town.
My big problem is getting on and off the trike. Presently I straddle the front beam/mid drive then waddle back and/or just pull the trike frame forward. Have issue raising legs over objects.
My plan is to use 1/2" emt electrical conduit then cover with clear vinyl plastic using riv-nuts.
Edpedlecar used these on his creation Purchased a really good riv-nut installation tool with lots of sizes available in metric or english (us measurment). Planning on 10/24 button head bolts and grommets in the vinyl.
 
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Lots of rivnuts and steel bolts could add up to a lot of weight. Have you considered nylon nuts and bolts? If they're only holding unstressed plastic panels their lack of strength won't be an issue and they are much lighter. I seem to remember calculating a saving of a couple of pounds or so on the Mk1 drypod.
 
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Replace the steel and steel rivnuts with aluminium variants, and the weight becomes a lot more managable.
https://www.amazon.com/Aluminum-Flange-Nutserts-Rivnut-Threaded/dp/B07SG1W37G/ref=lp_16410051_1_12?s=industrial&ie=UTF8&qid=1600148223&sr=1-12

But there are other options. I like to work with UHMWPE.
  • Virtualy unbreakable.
  • Cheap
  • Light
  • Can be welded with a good hot air gun and welding material.
  • Bend/moulded with the application of heat.
  • Impervious to most, if not all chemicals people can encounter in daily life.
I found a few disadvantages of the stuff tough.
  • It's a PITA to glue. Certain hotglues do it a tad better. But it's not a methode I would trust for structural integrity.
  • When bolted, you need big washers
Cosmetics are another weak point..
  • White, green or black in color. With black the most UV resistant. You can have it in any color, but then it's a custom made batch. Forget the cheap then.
  • Painting is as difficult as glueing.
  • It scratches easely.
 
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I've started cutting the plywood and it looks damned flimsy to me, especially with some go faster holes cut in it. Once it's screwed and glued it may look somewhat sturdier. In an effort to be kinder to the wood I feel I may need to add front suspension and thus send a lot of the loads into a spring. To use an external spring unit means making the wishbones longer and wider than I want to fit the unit up the middle of them. I can keep this down to 1m wide if I make the wishbones smaller and then move the suspension unit inside. 125mm units have about 20mm of travel but leveraged like this it gives 28mm of travel at the wheel which will have to do. Too much will have it rolling too much anyway. It's not a small effort to make this and it'll add about 2kg over a solid set-up. The good news is such a set-up could probably make use of cheapo 125mm 450lb units.

 
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One wooden chassis.





About 8 hours from first cut to this. Everything came out of one sheet of 8' x 4' x 12mm plywood so not expensive either. I've screwed every two inch and glued the joints. The seat squab looks ridiculously short but the end of it is exactly where the bracket for the seat base will go and as such the forces go down the vertical bit under it. I will also employ a bit of angle aluminium and some bolts on the join of the underseat brace to the main sides and the seat back to the sides just to beef up the main load bearing areas. I've added as much hole as I dared to the structure. The side bit behind the seat back can stay as holes but those forward will need some correx behind them to keep the weather out as will that bit behind the rider.

And now..........drum roll please................ I said in post #1 "I think the wooden chassis is going to hit 12kg itself". I can now reveal I am stunned to have hit that target spot on. Of course that will be sod all consolation if it fails. Once I've got the seat in I'll chock some wood under the relevant points and see.

One thing I thought of whilst working on it today was if I can get a laundry basket the size of that top bit behind the rider I can bolt it there as the cargo area so when the body rises there's still a set of walls to that area similar to a folding hard top boot on a car. If I can't get such a basket then Thermhex will do the job.
 
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Very impressive start.

I can't judge from here where you expect your head and shoulders to be ?



I wondered if you could leave some of the front body work and windscreen in place and make the rest behind it slid up the sides of the existing frame in one piece ? rather than it all hinge forward ?

Slide in effect up the blue sloping line ? the wooden version looks plenty strong enough ?

Not sure if you have seen this ? a Quad but with lot's of interesting ideas including suspension over the top of the feet ?

Finish 1cv ?



Paul
 
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