Potential New Trailer build for 08'

[Charles]

I took some of my own feedback as well as the feedback from others in the "membership meeting" thread also in this forum and got a quote on what I feel would cover most of our needs. This should fit into our budget.

5x10 V-nose enclosed trailer in the following configuration:

Rear double barn doors, no side door.

Roof vent included

66" or 5 ft 6 inches of headroom inside.

30" x 30" window on one side, we could possibly do one on both sides.

Rear stabilizer jacks so the tongue doesn't flip up in the air when someone steps in the back

This should leave us with an empty weight right around 1,000 lbs + ~ 400 lbs of cargo.

Other options available but I didn't see the need:

Side door, this has only seemed in the past to promote poorly loading the trailer........ throwing everything heavy right on the tongue end of the trailer

Standard height is normally only 60" inside, they can do 66" or 72". 72" would mean more weight and more drag while towing.

Ramp door in rear, other than the chalker for SPJC we don't need to "roll" anything in or out.

In addition to the aero advantages of the V-nose, it's a great place to install a few small shelves to store things like the radios and our bins.

Add our own electrical feed to trailer with external connection to the generator.

Add a shallow and short countertop on one side for timing, plumb in the A/C and goto work.

Thoughts?

[Loren]

A few thoughts.

Ultimately, I think people for years to come will appreciate a few extra inches in height. I'd make it 72". Anyone under 6' can stand in that... and folks over 6' tall are used to ducking, anyway!

30x30 is not a large enough window. Maybe a pair of them for a more panoramic view?

I assume these are plexiglass/lexan windows. Good for looking though, but I think some sort of door to cover them on the outside would be good during towing and storage. Ideally, a well-framed flip-up door with good solid props to hold it up would be great. (I've seen this done before, and can probably get photos or maybe even drawings of how it was done) It would add a little weight, but also some protection during storage and towing, and a little less glare at the timing desk.

Now that I think of it, the trailer we had in Wichita was pretty well configured. It was custom built by clubmembers (somebody worked at a trailer fab shop) the way they wanted it, and then revised over the years to improve it.

It was probably an 8x16' trailer, not small. Back end had a drop-ramp, which is a lot easier to load, btw. (no lifting of piles of cones or anything, just walk them in) Each side had two flip-up doors that were probably 4x3' with a counter along both sides at the bottom of the window. The doors were cheap and lightweight wood-framed, fiberglass-faced with styrofoam core and steel prop rods.... typical cheap trailer fare. (NOTE: These doors were redesigned after years of use and abuse and falling apart and falling on people's head, and replaced with welded steel frames skinned with aluminum and custom folding stays that held the door from falling down OR blowing up... it would be well worth doing this part of our trailer right the FIRST time) Eventually, plexiglass was added to the inside on one side of the trailer. The other side was left open so that registration could be done through it. In bad weather, the open side could be closed to cut down on wind. This trailer did have a front access door (not on the side, on the very front). This allowed the ramp door to be closed in bad weather while still allowing access.

For a 5x10 trailer, we could probably stick with the "viewing" windows on one side, and maybe do just one smaller "registration" window on the other side. (it's surprising just how convenient and nice it is to do reg from this kind of a setup vs. doing it on a picnic table, or a table under a canopy, or whatever... looks more "professional" too)

All of this will add a little bit of weight, and quite a bit of cost... but if we want to do it right...

[Alizarin]

There's also the option of sponsorship. Maybe they give us a price break and they can put their logo all over it too.

[Charles]

Points well taken Loren....... I too was skeptical on that size window for course viewing. Good idea on running reg from inside, and yeah 30x30 is sufficient for that.

I will see what I can come up with on weight added to goto 72" inside, I suspect not much.

Anyone have an idea how to do a ballpark calculation on drag coefficient of 5' wide 66" tall vs 5' wide 72" tall assuming a ~ 5' tall tow vehicle. Overall trailer height in both scenarios will need to have ~16" added.

I wouldn't be so concerned about the drag if the trailer didn't have to routinely travel such a far distance at 55mph+ speeds.

Keep the feedback coming....

[TracAction]

I like the idea better of having a flip up window larger..... is better and if we could do one on each side it will give nice air flow with the back open.

+ the flip up windows/bays will give extra shade coverage for inside.

- the flip up window/bay openings would be harder to keep a water tight seal for storage and towing.

[Charles]

I like the idea better of having a flip up window larger..... is better and if we could do one on each side it will give nice air flow with the back open.

+ the flip up windows/bays will give extra shade coverage for inside.

- the flip up window/bay openings would be harder to keep a water tight seal for storage and towing.

Correct me if I'm wrong, but I think Loren was talking about flip-up cover panels for the regular windows we would install in the trailer.

The regular windows would be water tight. These panels would just give the windows protection during storage.... towing... and some shade for registration + timing/laptop.

SPJC yes we have a breeze usually, I don't think a wind greater than 2mph has ever blown thru Brooksville though

[Dave-ROR]

Figuring out drag without a drag coefficient is hard, and figuring out a Cd value for a trailer is really hard since none of us have seen it or anything.. the equations are out there, no way i'd figure it out though - I'm not that smart Kenny?

Rear ramp door is better than the two side openers for sure.. it's not the ability to roll stuff in and out so much as the ability to walk things in and out without climbing stairs.

[Loren]

Correct me if I'm wrong, but I think Loren was talking about flip-up cover panels for the regular windows we would install in the trailer.

The regular windows would be water tight. These panels would just give the windows protection during storage.... towing... and some shade for registration + timing/laptop.

Well, I was being intentionally vague. I'm sure the trailer builder you spoke with was probably talking about a glass, weather sealed window.

If we're going to the trouble of constructing a heavy-duty "door" to cover the window, the window doesn't need to be substantial at all. Put some weatherstripping around the door and it will be adequately water tight. As for the windows, if we go this route, all we need is a sheet of plexiglass screwed to the inside of the trailer. We could do that part ourselves easily enough.

So, my "vision" is well-made prop-up doors that will provide shade when open and be supported well enough (not just from their own weight, but from being blown upwards by wind gusts and subsequently crashing down) to avoid falling on people's heads, and keep the inside of the trailer dry and protected when closed. With "glass" being a simple tack-on feature.

[Charles]

I'm sure the trailer builder you spoke with was probably talking about a glass, weather sealed window.

Correct, it would open roughly halfway like a regular window....

[Jamie]

Anyone have an idea how to do a ballpark calculation on drag coefficient of 5' wide 66" tall vs 5' wide 72" tall assuming a ~ 5' tall tow vehicle. Overall trailer height in both scenarios will need to have ~16" added.

The coefficient's not going to change -- it's dimensionless. The overall drag will change mostly in proportion to the increase in exposed flat plate area. If the whole front were exposed, you'd be looking at about a 10% increase in drag. With less than have the trailer exposed above the tow vehicle, it'll be less -- how much less depends on the tow vehicle and how it's shape interacts with the trailer behind -- in a straight line, it's the same effect as drafting. For a trailer with a rounded or V-shaped nose, I think the height change won't make enough difference to worry about.

Jamie (a practicing aeronautical engineer at one time)
'01 Miata, '92 Prelude Si
Speed Demon Racing
http://luxpermanet.typepad.com/speed_demon_racing/" onclick="window.open(this.href);return false;

[Alizarin]

Figuring out drag without a drag coefficient is hard, and figuring out a Cd value for a trailer is really hard since none of us have seen it or anything.. the equations are out there, no way i'd figure it out though - I'm not that smart Kenny?

Its a little more difficult because you'd have to take the slipstream caused by the tow vehicle out of it, but the equations aren't that difficult...

D=0.5*C*p*A*v^2

C is a drag coefficient, which varies from case to case
p is the air density (mass per volume)
A is the effective cross-sectional area of the body
v is the velocity of the body

Increasing velocity is where it gets you. The other stuff is constant. Interesting note, that's also how you can calculate terminal velocity.

[Native]

drag coefficients are cool, but as long as it tows easier than the one we have now, does it really matter? A six foot v-nose is at 1000-1500 pounds that is balanced on the wheels not tongue has GOT to be better than what we have now - at what, 7 feet plus, no v-nose and at least 500 more pounds...all on the tongue...

I agree about windows or something on two sides, plus the door, and now that I think of it, 30x30 is kinda small - maybe 30x60, with 30x30 on the other side?

[impalanut]

I was looking on line and saw a number of trailers. I think 6x10 or 12 would be good. We should have windows on three sides. It would be good it they would open. I like the idea of flip up covers for both protection and shade. A side door is important because you want to load back to front. If you only have a back door this will be more difficult. I saw a few places where the basic trailer would be about 1600 to 1900 dollars new. Extra for the windows and such would bring it to about $3000. I have seen a few decent trailers by name brand (Pace, etc) for 1600-1900 used. I would guess these are better than the no name new ones. Maybe we could get one of the local companies to give us a deal in return for advertising (sponsorship)

[impalanut]

http://tampa.craigslist.org/car/481723382.html" onclick="window.open(this.href);return false;

How about this trailer in St Pete

[Jamie]

D=0.5*C*p*A*v^2

Interesting note, that's also how you can calculate terminal velocity.

Of course it is -- by definition, terminal velocity is the point at which acceleration due to gravity for an object in free fall is balanced by deceleration due to drag.

[Native]

Took a quick and sort of accurate measure of our trailer at the event today. 12x7, close to 7 feet tall.

That craig's list one above looks good, except for lack of a v-nose and it seems the horizontal ramp door was a well-liked idea...but for 1200 (or less...).

[Charles]

I'll keep an eye out for a clean used V-nose w/ramp door.

We've still got a little time to be picky enough to hold out for a V-nose I think....

BTW: this site is a powerful way to search craigslist........

http://www.crazedlist.org/" onclick="window.open(this.href);return false;

Edit: Just e-mailed 3-4 people on reasonably close ones that may fit the bill...

[Charles]

Took a quick and sort of accurate measure of our trailer at the event today. 12x7, close to 7 feet tall.

The real question is if loaded efficiently, how much actual floorspace do we need to hold everything? Seems like the section from our side door back would hold everything which i'm guesing is 6x8' ish ?

[Native]

Yep, we're not in a huge rush, and if you don't mind watching the ads, that would be great. Technically a new trailer won't be in the budget 'til next year, but I don't think there'd be too many objections if a "Deal too good to pass up" comes along before '08...

yeah, a 6x8 load area is probably about right. maybe even less...

[impalanut]

We should also hold out for at least 6 ft tall inside. Even though we could cram it into a 5x8, a little extra space means you don't have to fill it to the roof, that a few people can sit inside without sitting in each others lap, and the weight difference between a 6x10 or 12 is only a few hundred pounds more than a 5x8. Also, as we discussed at the end the day, we should be able to sell our trailer for a decent amount. I would guess 1500-2500 based on what I am seeing on the various ads.