DangerBird overcover vent first impressions

[Nhott]

First off the specs.
Order #862
DangerBird
Length: 10ft
Layers: Single Layer
Outside Fabric & Color: 1.8 Night Grid
Suspension: Cinch Buckle
Asym Lay: Right
Ridgeline: 2pc w/split at foot end
Extra Zipper Sliders
Net: Left side
Overcover: Left side
Tie-outs
Type: Upgrade to Pack Hooks
Custom Work
Description: Netting on last 12" of overcover

So far so good on the overcover vent window. I received the DangerBird last Wednesday. I spent Wednesday (31 degrees), Thursday (40 degrees) in my garage, and last night at Antietam Shelter (mid 30's - low 40's). Thus far I have been able to keep the overcover fully zipped with no issues. The vent seems to be perfect. It is keeping in a considerable amount of heat. I woke up this morning half covered up thinking it was rather warm, unzipped it to stick my head out and I could feel a big temperature difference. I haven't had any condensation issues, perhaps it hasn't been cold enough out. I don't have any experience using an overcover other than this one so I really don't know, but it's working out great in this weather. I have never been more impressed with any cottage vender. I can't begin to say enough about PapaSmurf and MamaSmurf.


Here are some pics that Randy took last week and some from this morning when we were packing up.

[Countrybois]

Nice! That is a great idea! Keep us posted on its effectiveness.

[CamoEvo]

Thanks for posting!

[PapaSmurf]

I think the trees that the brown hammock is using might be the exact same trees I used last time I hung at Antietam Shelter. It's a beautiful spot back there. Good news on the success of the vent so far.

[mcallaghan]

Thats actually a really awesome idea for the overcover...

[Yukon]

Neat design, I like it. Doesn't seem like it would be difficult to block it off if you needed to as well...

[AaronMB]

That's slick. Thanks for the highlights and the great pics. Is there a net that can be swapped out?

...I'll have to head over to Dream Hammock and check out the options.

[PapaSmurf]

Is there a net that can be swapped out?

The DangerBird hammock comes with both net and overcover attached to the hammock and you choose which one you'd use.
See this page for the details.

[Nhott]

I did some research before contacting Randy about the overcover which was literally last minute. I'm not the first to try this but I couldn't find any info about it on the forums. Randy informed me that he has done it a couple of times with some success.

This started out for the plain and simple reasoning of having an overcover and not zipping it up the entire way bothered me. Call it an anal retentive spell if you will. The vent is an experiment and I am not an engineer, just average intelligence. Having said that..

I researched the effects of a screen vs an open vent using natural ventilation and came across a study on greenhouses. Yes I know a greenhouse isn't a hammock but it got me thinking. The study showed that a screened opening (intake and exhaust) cut air velocity down while increasing heat and adding a more gradual internal temperature rise. Without screens the temp just inside the opening matched the outside temp. It also created a more dispersed air flow pattern.

Thinking about differential pressure, if the same holds true in the hammock then roughly at the point of the opening is where the internal and external temperature/moisture level out and this is where the moisture will collect. I know the hammock and overcover are both breathable but I never looked into air flow distribution specifics so here is where more guesswork comes in. By adding the mesh window on the overcover, air flow decreases but the hope is like in the case of the greenhouse that internal air mixing increases while trapping heat and eventually drawing the hot air and moisture up through the mesh before equaling out and condensing.

I'll keep testing it in different conditions and see what the limitations are.

[Crowell392]

That is a very similar idea that I wanted to do on my warbonnet XLC