Wondering about potential of plywood velomobile

SaladFish

SaladFish

10 W
Joined
Dec 14, 2015
Messages
71
I was reading tahustvedt's velomobile build thread and what I like about it was how the body was constructed from cnc routed plywood and other parts he assembled or made himself. Very impressive.

HFb4HAi.jpg

[youtube]OJreLisEav0[/youtube]

Project: Home made velomobile design with crank or mid motor
https://endless-sphere.com/forums/viewtopic.php?f=28&t=62827
I see the potential in a having a cad file with optimized left/right/top and bottom aerodynamic sides.

  • Adjust track width, height and lefth with a slider.
  • Select top and side window, door and wheel cut out options
  • Send the file to a CNC routing company to be routed.
  • Assemble sides with glue and paint.
  • Mount to recumbent frame and paint.
  • Super speed with minimal cost and expertise required.

I would of course want something much faster but with enough turning circle for the street.

iLFC1iJ.jpg

All Overzealous is clearly a fast design at 73.95 mile or 119.01km on the flying 200m. http://www.ihpva.org/hpvarecl.htm#nom01m
Although these are AUD $16,500 to buy.

So with left right aerodynamic profile and top and bottom aerodynamic profile. Internal wheels and a roof door that hinges at the front for easy entry. A nice extraction fan for ventilation, some fancy windows for good viability and reduce claustrophobic feeling.
5Yq3Zqp.jpg

Super plan

I wonder about the Cd of such an optimized design and if it could travel upwards of 60km per hour at 200w using electric motor. Milan SL proportadly travels at 185 watt at 60km per hour. http://velomobiles.ca/MilanSL-speed.html
 
One route people go is a tadpole with a body over the top. The less worrk, the better the chance of completion. What's your background? Are you ready for serious fabrication?
 
Dauntless said:
One route people go is a tadpole with a body over the top. The less worrk, the better the chance of completion. What's your background? Are you ready for serious fabrication?
Click to expand...

Yes I would be welding a tadpole frame then using CNC routing company to produce the plywood body panels that I would then assemble. I don't have CNC router and CAD is not something I could get into myself despite my efforts too intuitive.
 
Maybe take a look at early aircraft design, materials, etc. Wood is an amazing material with some properties that can't be beaten even with modern synthetics but it's not easy for hobbyists and small scale operations to get the best out of it, the same kind of design tools exist but they're mostly aimed at the construction industry. The best source of info I've found so far is aviation and keep bamboo in mind too, it's kind of a miracle material and the structural property figures are easy to find but it doesn't come up in aviation a whole lot.

Imho you'd be better off with a wooden frame and a different material for the skin (aluminium, fibreglass, carbon fibre, etc.) but that's just my relatively uninformed opinion, I'd spent a little time digging in to similar construction but not enough to claim any kind of expertise.
 
Like the looks! Wood is great for the home Hobbyist and heavy. Like the idea of velomobile but it is hot most of the year so fully enclosed is not ideal. Would like to keep the rain off, some aerodynamics. Like the design, keep doing the good work.
 
Stitch and glue tortured plywood is the route I'd go with plywood. Too much flat surface on the sides in the OP's example. I'd get blown all over the road by wind and trucks. When I finally do a velo I'll do a flyweight construction along the lines used by geodesci airolite canoes. The GABoats.com website is now down, but a 6lb canoe shows up in Google images to give you an idea, and a velo could be even lighter...less wood less strength required. You make a balsa frame (grows naturally down here, a junk wood often used to make pallets). Paint a thin layer of epoxy on the outer surfaces and stretch Dacron over it. Once the epoxy cures and the dacron is secured to the frame, use a heat gun or iron to shrink the Dacron for a tight clean smooth finish.

It seems like such a no-brainer easy approach to a great result that I'm surprised we haven't seen lots of velos made this way, much less exactly 0.
Skin on frame canoe.JPG
 
John in CR said:
Stitch and glue tortured plywood is the route I'd go with plywood. Too much flat surface on the sides in the OP's example. I'd get blown all over the road by wind and trucks. When I finally do a velo I'll do a flyweight construction along the lines used by geodesci airolite canoes. The GABoats.com website is now down, but a 6lb canoe shows up in Google images to give you an idea, and a velo could be even lighter...less wood less strength required. You make a balsa frame (grows naturally down here, a junk wood often used to make pallets). Paint a thin layer of epoxy on the outer surfaces and stretch Dacron over it. Once the epoxy cures and the dacron is secured to the frame, use a heat gun or iron to shrink the Dacron for a tight clean smooth finish.

It seems like such a no-brainer easy approach to a great result that I'm surprised we haven't seen lots of velos made this way, much less exactly 0.
Skin on frame canoe.JPG
Click to expand...

I have been watching some of his videos on Youtube. It is very interesting.

I need to determine what size wood I should use for nonstructural shell. Then I can check my local suppliers.
 
If you're hell bent on going fast with 200W (sort of a questionable proposition to begin with) then buying something like a high racer recumbent will be much cheaper and easier than designing and building your own velomobile, which is a substantial undertaking your questions suggest you are entirely unprepared for.

Keep in mind those speed records you're seeing are with a pro cyclist putting out over 1000 watts.

If it were up to me I would just make an ebike with whatever power level I want then ride it responsibly enough to not attract attention. Actually many of us have already done that with excellent results.
 
If you want to learn how to make a super light, super strong, thin Carbon body shell for a Velo, Aircraft, or anything,.....watch a few of Mike Pateys videos.
https://youtu.be/pBGY57ILDlQ
But be warned.....he will wear you out with his energy and work rate !
 
flat tire said:
If you're hell bent on going fast with 200W
Click to expand...

Speed I already have way more than I use, so I have no intention of riding in a vertical lima bean with wheels. I want practical vehicles.

I want 2 things, probably from 2 different velos:

1. A ride for the rain without getting wet. Because this would be for regular use around town the biggest issue will probably be easy in and out.

2. A 200 mile range ebike or etrike cruising at hopefully 50mph or more, most likely along the lines of a Velotilt delta leaner but punching a somewhat larger hole in the air with extra room for comfort, and a 6-8kwh battery pack.
 
The DeHavilland Mosquito was highly respected. Mostly wood skin.

You can take thin plywood and apply very thin cuts on one side, many of them side-by-side like the teeth of a comb. That can help the plywood make a graceful bend.

Also, possibly experiment with steam-bending wood and plywood. There are also certain thick and stiff plastic sheets that can be heated and bent.

Google wisil missile
 
John in CR said:
…You make a balsa frame (grows naturally down here, a junk wood often used to make pallets). …
Click to expand...

You can stiffen up balsa with the thin cyanoacrylate (superglue) that model airplane makers use. Makes balsa strong and hard, but also more brittle. I made a 2" X 2" footlong 'bridge' using 1/16" balsa sticks for HS physics class that was the only one in the class that was engineered at all, and it was all triangles. Everybody else's bridge just bent mostly and held less than 10 lbs. My highly engineered, cyanoacrylate-soaked bridge held 69 lbs. and instead of bending, didn't perceptively move and just made a 'snap' sound when it failed. It weighed nothing.
 
spinningmagnets said:
The DeHavilland Mosquito was highly respected. Mostly wood skin.
Click to expand...
ah yes, the spruce moose(quito) as it was called in Canada. :lol:
John in CR said:
You make a balsa frame (grows naturally down here, a junk wood often used to make pallets).
Click to expand...
rhetorical, but i would like to know then why the hell balsa is so damn expensive in hobby shops.
 
In hobby stores it has been cut up in a labor intensive manner where much wood is destroyed, as balsa is not easy to work with. Then it's been shipped halfway around the world. Lumber yard balsa is cheaper but not cheap.

At weights less than double that of balsa you find spruce, cedar, Willow, I understand there's something in Europe called linden.

A balsa build will be harder than you think, as well as more fragile. You'll have to do some serious hotcoating, it'll oak the resin up and get heavier. I'd suggest fiberglasing right over, heavier still.

You could try something I've experimented with but no serious build yet. Honeycomb pads will surprise you with their strength, which actually isn't so important. The idea is to fiberglas right over it. https://www.uline.com/BL_1856/Honeycomb-Pads
 
Dauntless said:
balsa is not easy to work with...Lumber yard balsa is cheaper but not cheap.
Click to expand...
not cheap only outside CR apparently.
the hobby shop owner who cut me a length in half with a hand saw wuz like 80y.o.
just how hard can it be to work with?????
wiki said:
Linden is one of three English names for the tree genus Tilia (also known as lime and basswood). Other trees include:Vibranium linden
Click to expand...
made ya look
 
Toorbough ULL-Zeveigh said:
rhetorical, but i would like to know then why the hell balsa is so damn expensive in hobby shops.
Click to expand...
What in a hobby shop isn't classified as "so damn expensive"?

I got some sections of a Balsa tree from Harold who found a fallen one. It's hard to work with because the grain is very short, it holds a crazy amount of water until dried and has drastically different qualities even within the same section of log. I do still have at least one piece quite similar to hobby shop grade that Harold milled into a 4"x6" piece.

If I was stateside I'd look for paulownia which is almost as light, stronger, and longer grained so easy to work. On YouTube I saw a guy who built an 8lb canoe with spruce stringers, steam bent oak, and a Dacron skin.

We don't need anything nearly so strong as a boat as the steel frame would support all the bike/trike stuff. We just need a shell that's rigid enough against the wind with a strong enough structure to create solid attachment point. It won't have to support any load other than the wind. Think more along the line of how wooden airplanes were made, but even less strength requirement due to the road worthy structure to which the aerodynamic shell attaches. I'll definitely build and have sufficient weight of me, battery, motor, cargo, and frame combined with a low CG that concerns about shell strength required by the guys attempting human power records in very unstable vehicles won't be an issue. Mine will be stable while stopped, going slowly or fast. I simply want to make a relatively small hole in the air, and slip through it with very little wind resistance creating very little turbulence.

The electrathon record of 62miles in one hour used 0.95kwh battery was set in 2009 with a very sleek and low tadpole. https://web.archive.org/web/20101122045520/http://evmaine.org/html/worldrecord.html. It consumed only 15.3wh/mile, so I believe a much longer range and more comfortable vehicle is possible that could be useful as real world transport and consumes only 20-25wh at 50mph.
 
briangv99 said:
John in CR said:
If I was stateside I'd look for paulownia which is almost as light, stronger, and longer grained so easy to work.
Click to expand...
Forum member zappy started builidng a paulwonia shelled velo quite a few years back. I still have the shells sitting under my house waiting for a frame and drive train
Click to expand...

I always wished you guys had finished that up to get us all rev'd up with great speed and low consumption numbers. The wood strip was going to be beautiful and likely to handle a spill. I'm too lazy, so I'll come up with the easiest way I can to build a frame with the fewest strips I think I can get away with, then glue and shrink a dacron skin on. If the result proves not to be rigid enough, I can easily apply a glass layer inside.
 
John in CR said:
If the result proves not to be rigid enough, I can easily apply a glass layer inside.
Click to expand...

Sounds like the place you'd want kevlar. I wouldn't go looking for stiffening from the surface, I'd say figure out some bracing.

Toorbough ULL-Zeveigh said:
the hobby shop owner who cut me a length in half with a hand saw wuz like 80y.o.
just how hard can it be to work with?????
Click to expand...

Hard enough that you have to use a hand saw.

wiki said:
Other trees include:Vibranium linden
Click to expand...

Is that part of the Marvel Universe? Sounds like the trees you'd find in Black Panther's homeland.

wiki said:
made ya look
Click to expand...

I'm not touching you, I'm not touching you.
 
Dauntless said:
John in CR said:
If the result proves not to be rigid enough, I can easily apply a glass layer inside.
Click to expand...
Sounds like the place you'd want kevlar. I wouldn't go looking for stiffening from the surface, I'd say figure out some bracing.
Click to expand...

Inside the frame, which would provide tremendous stiffening of the structure, not just an addition to the skin.
 
https://www.alibaba.com/product-detail/Vacuum-forming-custom-golf-cart-body_60719639187.html

Group buy? :lol:
 
John in CR said:
Inside the frame, which would provide tremendous stiffening of the structure, not just an addition to the skin.
Click to expand...

The composite would make the sacraficial ply on the outside. If you put it on the inside for structural support you need a balanced ply on the outside. The stronger it is the more self destructive an unbalanced ply can be. The inside is still surface.

More important is the strategic placement of the stiffening. When they do aftermarket stiffening of a street car some use cable. Not even stiff, probably not near as strong as the frame, but working in exact the direction they want the stiffening. What people think is the driveshaft space inside the car is called the chassis tunnel, no driveshaft inside but greatly strengthening the chassis lengthwise. Put a roll like that in a sheet of paper and look how it doesn't flex when you lift the end. Even with tissue paper, I sat here and tested that before i posted it. longer floppy. Adding weight with a laminate doesn't have that effect, they make leaf springs from composite and they flex.
 
Dauntless said:
John in CR said:
Inside the frame, which would provide tremendous stiffening of the structure, not just an addition to the skin.
Click to expand...

The composite would make the sacraficial ply on the outside. If you put it on the inside for structural support you need a balanced ply on the outside. The stronger it is the more self destructive an unbalanced ply can be. The inside is still surface.
Click to expand...

I see what you mean about an unbalanced ply. The shell would be just for aero and/or shielding from the elements, with the vehicle frame inside sufficiently rigid to work without the shell. Extra attachment points and very light additions to the skin's frame structure should pick up any rigidity needed.

I'd like to retain the simplicity, light weight, and easy repair of a painted dacron skin. Unlike on a boat a hole is little more than an inconvenience with tape a simple temporary repair.
 
You must log in or register to reply here.

Similar threads

Reid Welch
"Extreme MY1018" archival, closed out
Replies
11
Views
16,896
GIGATT
G
Back
Top