Tested: Duckworks vs. Van's

RV7ator · #1 11-04-2005, 06:49 PM

A week-ago thread about the new 715-1 wing tips got into discussing leading edge (Duckworks) vs. Van's new tip light kit that fits the -1 tips. All comparisons were conjecture. Now I have some actuals.

History: Duckworks in my -7 are adequate. But like, horse power, more is better! I substituted a 100 watt halogen bulb for the 55w standard on the right wing, aimed for level attitude/landing. The left is aimed low and toward centerline for taxiing. I happen to have two Duckworks kits on the shelf ready to install in the current project (another -7), when the wing tip thread showed up, and I have the new -1 tips. Decisions, Decisions. I called Van's. Scott said that the tip lamp set-up would be shadowed by the position/strobe unit, and he opined that Duckworks would put more light on the pavement, but given that Van's had two lamps per tip, each 75w and individually aimable, they should be comparable or better, 2 x 55w vs. 4 x 75w as sold.

They aren't.

I ordered a Van's kit to see what it looked like. After examining it, I had questions, and another call to Van's got a different person who said that they have not installed this kit in any aircraft, so do not know how it would work in service. All Van's did was install it in a wing tip in the hangar, thinking that so many builders were rolling their own tip installation, Van's may as well offer something "that works". An interesting side comment was "they're used mostly for identification." Oh, really!?

My examination of the kit raised two concerns: shadowing and strength. Shadowing would come, not just from the strobe/position unit, but also from the face plate mounting the lamps. The lamps are recessed because of the slant of the tip face, yet set directly in line with the oval (again, because of the slant) cutout with a minor dimension equal to the lamp diameter. Should you want to adjust a lamp downward, especially a concern for a tail dragger, it would begin to illuminate the back side of the mounting plate, no longer shinning entirely through the hole. The strength issue is because much of the span-wise tip face is removed, leaving a 1/4" flange around the cutout. That greatly weakens the tip, not fully recovered by the face plate being held in position by a few screws. Not a big issue, though, unless someone pushes on the tip, but it is undeniably weakened.

Stepping out into the pasture with battery, DW, and Van's, this evening produced these observations.

Duckworks uses a driving light (I'm seen the exact units in a car parts store) with a rectangular reflector. Removing the glass diffusor, per DW instructions, and the 55w bulb projects a concentrated oval beam, about 18" x 12" at 8', with no halo. The shape is important because it will be projected at an angle to the ground, so the narrow vertical dimension of the beam won't get smeared over too much ground. Remember, it's designed as a driving light. At dusk, objects 100 yards away are brightly illuminated. Colors are very discernable. Holding the diffuser in place produces - an automotive headlight pattern. Gee. Who'd a'thought.

Van's lamps have a bit of a hot spot in the center, but overall the light is widely dispersed in a round pattern. The outcome is that beyond 25 yards, objects are not brightly illuminated, colors are mushy. Again, this is a 75w lamp. It's added power is spread thin. Two lamps won't add much to what you see.

The whole point is to throw bright light a good distance down the runway. For this a 55w Duckworks blows away a 75w Van's. For taxi, install the DW diffusor on the left side (I did on the -7). Van's would be excellent for taxi; landing, um, you'd get out an expletive before hitting the moose. DW, you'd also be able to go around. Combined with my concern about shadowing of the Van's installation, and the fact they haven't actually flown it, Duckworks gets my money.

John Siebold
Boise, ID

bmurrish · #2 11-04-2005, 07:49 PM

Great post John. Have you ever considered upgrading to 100w halogens in the DW like Dan Checkoway did? I wonder how much of an improvement it would be.

Captain_John · #3 11-04-2005, 11:27 PM

Seems that I recall that Dan swapped out his 100's for 55's in lieu of less amp pull and not much change in illumination.

I have done similar things on my land based vehicles. The 55 isn't THAT much worse than the 100's.

Light is light is light.

CJ

sprucemoose · #4 11-05-2005, 02:43 AM

I disagree. I swapped out my 55Ws for 100s (Available from NAPA) and I think they make a big difference.

Kyle Boatright · #5 11-05-2005, 05:31 AM

A bit of thread drift, but I only have one Duckworks light in the left wing of my -6. If I was gonna do this again, I'd have one in each wing.

The one light just doesn't illuminate thing well enough to make me comfortable doing night landings.

KB

dan · #6 11-05-2005, 07:08 AM

I use 75 watts now. With just my 40A alternator, I don't have as much current headroom as some people. Once I switch from incandescent to LED position lights (probably at the annual condition inspection in March), that will buy me some more headroom. In the meantime, I started using 75 watt H3 lamps, and I didn't notice much difference stepping down from 100W -- other than less current draw.

)_( Dan
RV-7 N714D
http://www.rvproject.com

RV7ator · #7 11-05-2005, 08:04 AM

The replies emphasize where Van's lost the bubble with their design. 300 watts requires 21 amps, sure to snap crankshafts. Half of that with superior illumination of the Duckworks, say 100 landing, 55 taxi, tells you that concentrating the light is better than a warm glow about a hemisphere.

Still, old and blind might make testing the alternator's output acceptable for the short time the battery may have to pick up the slack (albeit at a lower voltage). That, though, violates good design practices, and woe to you if you forget to turn off 300w after daytime position use in dense traffic.

Now, if we could get Gretz to offer a pitot heated by integration with hot landing lights, we'd get somewhere!

John Siebold

Davepar · #8 11-07-2005, 09:54 AM

Quote:

Originally Posted by RV7ator

...All Van's did was install it in a wing tip in the hangar, thinking that so many builders were rolling their own tip installation, Van's may as well offer something "that works".

I sure hope that isn't true. There are many more useful things they could do rather than redesign the wing tips over and over, and making a wing tip light that has already been offered by another company for at least 2 years. How about making a snorkel that actually fits the IO-360-M1B? (end rant)

Thanks for the helpful info on comparing the lights.

RV7ator · #9 11-07-2005, 03:17 PM

Dave,

That's what I was told after pointedly asking about flight testing the light kit. I don't know if Van's deepened the tip light well to facilitate other light installations (hard to imagine) while making the -1 change simplifying tip manufacture, or if they had their tip light set-up in mind from the get-go (likely). For sure, these tips are beautifully formed, far nicer than the Batman tips I got three years ago. The recesses receiving the wing skins and lens are straight, uniform depth, and the inside radii are sharp. Won't require near the fitting previously needed.

John Siebold

mlwynn · #10 11-07-2005, 10:58 PM

Hi all,

I am scratching my head over the lighting question. Looks like two lamps in each leading edge; one for taxi, one for landing. Does anyone have any experience with Van's HID lamps compared to the halogen ones? Quite a bit more money. Is there a lot more light?

Regards,

Michael Wynn
RV 8 Wings
San Ramon, CA