Aerodynamic trailer plans

[tony.latham]

Hey guys I dont want to be a dick but if you want to debate his figures please do it privately or in a new thread.

I am really hoping for real, factual, advice on my build.

Thanks!

This will certainly be an interesting build to follow.

Hopefully, you can find some balance between the aerodynamic challenge and making it camp-able.

Tony

[Tigris99]

Oh I'm not debating, just trying to throw out some thoughts to take into consideration from my experience. Theres A LOT to take into account so I was sharing some info.

I'm following as well because I want see where this goes, has me very intrigued.

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[rowerwet]

The car and tear in My avatar did many trips this way, the focus has a pretty accurate MPG computer.
The whole combination, with fully loaded camping gear cost us about 6 mpg.
The biggest variable is speed.
55 mph cost the least, 60 was 2 more, 65 4 more than 55, 70 and 75 it settled in at 6 mpg, with each reading taken after a half hour with the cruise set.
At 75 mph I was still being passed by many people.

More than one person has found that a kayak or canoe on the TV has increased their towing mpg.

I'm about to rebuild this tear as a bowfront with an arched roof, like the runaway camper roof.

Weight is almost as big an issue as aerodynamic drag, my new build will be foam.

[OP827]

The car and tear in My avatar did many trips this way, the focus has a pretty accurate MPG computer.
The whole combination, with fully loaded camping gear cost us about 6 mpg.
The biggest variable is speed.
55 mph cost the least, 60 was 2 more, 65 4 more than 55, 70 and 75 it settled in at 6 mpg, with each reading taken after a half hour with the cruise set.
At 75 mph I was still being passed by many people.

More than one person has found that a kayak or canoe on the TV has increased their towing mpg.

I'm about to rebuild this tear as a bowfront with an arched roof, like the runaway camper roof.

Weight is almost as big an issue as aerodynamic drag, my new build will be foam.

Rowervet, you are saying that it costs you 6mpg less in your mileage comparing to a car mileage w/o the trailer, correct? Just making sure I understand this correctly. What is your mpg for car with trailer then?

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[jimbo69ny]

I just ordered my fiberglass and resin for my T-Rex aero build.

Check out my youtube channel if you want to see my build. youtube.com/jimbo69ny

[Andrew Herrick]

So, a small voice of dissidence here

If somebody is interested in pushing the scientific envelope and building a teardrop for the sake of science, then I say, more power to you! But if somebody is interested in building a usable, affordable, aerodynamic teardrop, then I'd humbly suggest there's no reason to substantially deviate from the norm. As has been pointed out by other posters, when towing a lightweight camper with a classic (or similar) teardrop profile and a suitable tow vehicle, there's minimal potential fuel economy improvements.

If you look at anything designed strictly on aerodynamic efficiency - human-powered bicycles, wind turbine blades, albatrosses, stealth fighters - you'll note that none of those look particularly inviting to live in. So, once a design has rounded body corners, underbody skid plates, recessed wheels and a teardrop-esque shape, you've done 90% of the aerodynamic work. Pushing for that extra 10% will harm the functionality of the interior. For instance, with all respect to Timm's CAD mockup - which looks amazing! - I wouldn't want to spend a rainy afternoon in that thing. Looks like a good candidate for a foam-epoxy build, though.

Anyhow, I love the ideas here. It's just worth pointing out for any new builders reading this thread that these are "research" campers and not necessary to build a high-quality camper. The big pro, as I see it, is you'll be able to drive 80 mph to your destination, and I'll be driving 65

[jimbo69ny]

So, a small voice of dissidence here

If somebody is interested in pushing the scientific envelope and building a teardrop for the sake of science, then I say, more power to you! But if somebody is interested in building a usable, affordable, aerodynamic teardrop, then I'd humbly suggest there's no reason to substantially deviate from the norm. As has been pointed out by other posters, when towing a lightweight camper with a classic (or similar) teardrop profile and a suitable tow vehicle, there's minimal potential fuel economy improvements.

If you look at anything designed strictly on aerodynamic efficiency - human-powered bicycles, wind turbine blades, albatrosses, stealth fighters - you'll note that none of those look particularly inviting to live in. So, once a design has rounded body corners, underbody skid plates, recessed wheels and a teardrop-esque shape, you've done 90% of the aerodynamic work. Pushing for that extra 10% will harm the functionality of the interior. For instance, with all respect to Timm's CAD mockup - which looks amazing! - I wouldn't want to spend a rainy afternoon in that thing. Looks like a good candidate for a foam-epoxy build, though.

Anyhow, I love the ideas here. It's just worth pointing out for any new builders reading this thread that these are "research" campers and not necessary to build a high-quality camper. The big pro, as I see it, is you'll be able to drive 80 mph to your destination, and I'll be driving 65

I kindly disagree. I have an EV so air resistance and range is VERY IMPORTANT. Sure you can refill your dino juice anywhere in 5 minutes and be on your way. I have to be as resourceful and efficient as possible. That's why I started this thread and thats why I am building an aero teardrop. Its going to be glorious! haha

[Andrew Herrick]

I kindly disagree. I have an EV so air resistance and range is VERY IMPORTANT. Sure you can refill your dino juice anywhere in 5 minutes and be on your way. I have to be as resourceful and efficient as possible. That's why I started this thread and thats why I am building an aero teardrop. Its going to be glorious! haha

Ah, you have an EV?! I apologize - I must have missed that information in the comments. Well, you're on the fringe, then. Have you ever considered a tent?

But seriously ... I'm not sure of the dimensions of your teardrop, but it might be worth looking into an aerodynamic rooftop tent setup. Or, since you're pouring all this time into a teardrop build, make it expandable, like an old Kampmaster. Then you can design the shell as aerodynamically as possible and not sacrifice all the quality of space.

[jimbo69ny]

I kindly disagree. I have an EV so air resistance and range is VERY IMPORTANT. Sure you can refill your dino juice anywhere in 5 minutes and be on your way. I have to be as resourceful and efficient as possible. That's why I started this thread and thats why I am building an aero teardrop. Its going to be glorious! haha

Ah, you have an EV?! I apologize - I must have missed that information in the comments. Well, you're on the fringe, then. Have you ever considered a tent?

But seriously ... I'm not sure of the dimensions of your teardrop, but it might be worth looking into an aerodynamic rooftop tent setup. Or, since you're pouring all this time into a teardrop build, make it expandable, like an old Kampmaster. Then you can design the shell as aerodynamically as possible and not sacrifice all the quality of space.

Anytime you put anything on the roof you take a 10-20% aero hit. If it was a tent then I would still have all of that set up to deal with, just like a tent, which I am trying to avoid by having a teardrop.

I havent mentioned this in this post but many others, part of my build is a range extending trailer. I built the first one in the world Feb - March of this year. Now I am building a second one. This time I am using a Tesla 85kwh battery pack (pictured in first post). I should come close to tripling my range. Check out my channel for more info if you are curious.

[Andrew Herrick]

Anytime you put anything on the roof you take a 10-20% aero hit. If it was a tent then I would still have all of that set up to deal with, just like a tent, which I am trying to avoid by having a teardrop.

I havent mentioned this in this post but many others, part of my build is a range extending trailer. I built the first one in the world Feb - March of this year. Now I am building a second one. This time I am using a Tesla 85kwh battery pack (pictured in first post). I should come close to tripling my range. Check out my channel for more info if you are curious.

Setting up a tent does certainly take more time. But just curious: Do you think you'll do markedly better with a teardrop trailer compared to the 10-20% aerodynamic efficiency reduction of a roof-mounted tent?

Hmm: Is this you? https://insideevs.com/range-extender-te ... ler-video/
Apparently the big shots are interested in a similar concept: https://evobsession.com/electric-car-ba ... dic-power/

As I said: You're certainly in the "for the sake of science" category I'll be curious to see what you come up with.

[jimbo69ny]

Anytime you put anything on the roof you take a 10-20% aero hit. If it was a tent then I would still have all of that set up to deal with, just like a tent, which I am trying to avoid by having a teardrop.

I havent mentioned this in this post but many others, part of my build is a range extending trailer. I built the first one in the world Feb - March of this year. Now I am building a second one. This time I am using a Tesla 85kwh battery pack (pictured in first post). I should come close to tripling my range. Check out my channel for more info if you are curious.

Setting up a tent does certainly take more time. But just curious: Do you think you'll do markedly better with a teardrop trailer compared to the 10-20% aerodynamic efficiency reduction of a roof-mounted tent?

Hmm: Is this you? https://insideevs.com/range-extender-te ... ler-video/
Apparently the big shots are interested in a similar concept: https://evobsession.com/electric-car-ba ... dic-power/

As I said: You're certainly in the "for the sake of science" category I'll be curious to see what you come up with.

Yup thats me.

A teardrop will be almost no deduction on the highway. Once you get all that weight moving for a 3 hour drive the car doesnt even know its there. Its in the slipstream of my car.

The battery is too heavy to put on top of the car.

Yeah I heard about that company. I bet they are years away. I could sell these now if I wanted to.

[timm]

For instance, with all respect to Timm's CAD mockup - which looks amazing! - I wouldn't want to spend a rainy afternoon in that thing.

Thank you, although it isn't as small as it appears. The top lifts up 18" with 4 pneumatic cylinders. This is a comparison between my current design and the Generic Benroy design you can find under "Design Resources".



The blue lines are the inside of my trailer and the black outline is the Benroy.

My door is slightly larger and my ceiling is a foot higher (50" vs. 38"). There's also a lot more room for storage inside the cabin.

[Andrew Herrick]

For instance, with all respect to Timm's CAD mockup - which looks amazing! - I wouldn't want to spend a rainy afternoon in that thing.

Thank you, although it isn't as small as it appears. The top lifts up 18" with 4 pneumatic cylinders. This is a comparison between my current design and the Generic Benroy design you can find under "Design Resources".



The blue lines are the inside of my trailer and the black outline is the Benroy.

My door is slightly larger and my ceiling is a foot higher (50" vs. 38"). There's also a lot more room for storage inside the cabin.

Timm ... I must have been looking at the wrong thing. I was referencing a different 3D solid mockup, an uber-aerodynamic mockup towed by the Honda Civic. Your camper looks substantially larger! So basically ignore what I said :p

[timm]

Nope, they are one and the same! The ultra-aerodynamic 3D model is the blue lines in that comparison.

Here's an animation of the top lifting up.

[Tomterrific]

I am convinced a pop-up roof is more aero than any full size tear. My trailer with only a plywood floor would pull effortlessly with two motorcycles or a tractor on it. Built the approximately 4 foot high camper and the extra wind resistance is quite noticable. Starting with a low raising roof design and then streamlining, that is the key.
So here is my plan for easy towing.
1. Design lifting roof.
2. Keep the trailer low. Like a Dexter axle rather than leaf springs. Small wheels.
3. Light weight. A underpowered vehicle will suffer as soon as the road goes from flat to up hill.

Tt