Off The Shelf Item List

I want to start a running list of possible Off The Shelf (OTS) Items for a small blimp. We need to list all kinds of things from power to props to materials. 

Please post the weight, cost, and any other important stats.

I will start off with power.

This is a Honda inverter generator. It is priced at $1280 on Honda's site. It weights about 46 lbs. It has a rated output of 1600 w and a max output of 2000 w. It can also be run in series with up to 2 other identical units. 

http://www.hondapowerequipment.com/products/modeldetail.aspx?page=modeldetail&section=P2GG&modelname=EU2000i%20Companion&modelid=EU2000IAN1

Wait. You're proposing to use a gasoline engine to generate electrical power, but how are you going to store that power? Batteries are heavy, expensive, and inefficient. Why not just use a similar-sized gasoline engine for direct power to the props? Much more efficient. You're on the right track with an air-cooled gasoline engine, though; gasoline offers better output per pouind of fuel and engine weight than other fuels. See my post under The Project.

Frank

The generator centralizes weight and complexity. An engine hanging off the side of an airship creates a need for more structure and increases drag. There won't be much storage, most power will go straight to the prop and to provide power for electrical systems. This will make adding more power easy and will ensure that power remains if one generator fails. 

But this thread should not be about discussion on pros and cons. It should be a list of items with specs. 

Here is a small Honda engine. It puts out 2.1 hp. Its dry weight is 12.1 lbs. It looks like you can buy one for less than $350. 

http://www.nehydro.com/index.php?main_page=index&cPath=8

The above is a link for Mylar for building some models, not sure if it has any backing for melting the sheets together or not, and I'm not sure if the weight is suitable for airships. 

I've used the below source in the past:  Felix Press aka Balloon Kits.   You can buy Nylon rolls from him that are good for heat sealing (205 degrees -- modelling iron) see info on his website:

http://www.balloonkits.com/

They have an instruction sheet on the website for working with the materials.

I just put in my order from Balloon Kits.  They called me with a question on my order (originally was going to be 2 rolls of the stuff I ordered before) but changed to the clear material which comes in 44" wide vs. the 38" for the colored material.  The different clear material is almost twice as expensive but is also wider, but the same weight and is twice as durable,  which is good, as my previous envelopes I made were sabatoged possibly by one or both of our cats exploring the basement...

I'd still like to order up some polyurethane so if anyone has a good source let me know.

Thanks, Paul

Maybe this is a source, even has an aerostat on the webpage and airships in the bottom link: 

   http://www.apiusa.com/?gclid=CKjP672XmKECFQtM5wodw0d3PA

   http://www.apiusa.com/polyurethanefild.html

Okay have some info from APIUSA.

6 mil is typically used for airships.  Their smallest shipment for an order is 300lbs (white) which usually runs around $20 a pound.  This gives around 7500 square feet of material to work with.

They do sometimes carry left overs.  I inquired on the 2-4 mil samples for a remote control that I'll be building.

Smallest quantity they have is 37 lbs at this point (still at $20 per lb).  So if the group wants to get around 750 square feet for model building we could buy some for $740 plus shipping I suppose we could get some good stuff to work with. 

Hes going to give me what they have as other left overs.

Here is a a pretty comprehensive netting site. This is a link to their plastic netting. http://www.usnetting.com/HTML/plastic-netting.html Stats are on the page.

OK I tried the live chat with U.S. Netting. It went like this ( with my background comments in italics)

Chat InformationPlease wait while I transfer the chat to 'Liz'.

Five min. delay

Chat InformationYou are not currently in a chat session.

Five min. delay

Chat InformationYou are now chatting with 'Liz'

This took about 15 min.  Liz obviously wasn't finished with her coffee.

Liz: Hello this is Liz

Swampie777: How much does your netting weigh? Do you have a standard adhesive for attaching the netting to other plastics?

Note this is TWO questions.

Liz: depends on what net you are looking at

Liz just graduated from the " great grasp of the obvious" school

Swampie777: Do you have technical info for all your products?

Liz: yes

Short answers gets you back to your coffee quickest

Swampie777: Can you send it to my email?

Liz: yes but we have so many different products you would need to narrow it to a couple of different products - are you looking at one in particular

Instead of doing work, just send the job back to the customer

   
Swampie777: Multi-Use "C" - 1-3/4" x 2" 4' x 330'

Liz: yes I have that information and I can send it to you by email

Just because you can - does that mean you will?

Swampie777: Please do. Thanks

Since there was a five to ten min. delay between each response it`s also apparent that "liz" is a fake name intended to throw you off from the fact that this chat is with someone in a third world country who is concurrently milking the cow in the kitchen.

Liz: ok

Swampie777: By for now.

US Netting  They make a really Cheep! cargo net for trucks that might work as lift bag partitions as well as possibly for envelope material. I know a net has more drag than a plastic shrink film but.....  at this price and ease of use, I want to experiment and ascertain just how much drag they add to the surface of the contained lift bags. 

 I mean, I'm only gonna be goin fifteen knots, no big blast of wind to it!

A 14' wide roll 500' long is just $310............!
http://www.usnetting.com/HTML/car-go-net.html

LOL sounds like a great chat. Hopefully they will get back to you. 

Other sites I found of interest during the conference.

http://www.runwayfinder.com/?loc=HSV

http://www.firstsolar.com/en/

http://nextbigfuture.com/2008/04/solar-power-breakthroughs-sunrgi-7.html

http://www.boddingtons.us/horticulture/plastic-garden-netting.htm

ThermoPlastic Welders at:

http://www1.mscdirect.com/Welders/Thermoplastic-Welding/Welding/s0002000654.HTMl

     Those are hot air welders, great for plastics thick enough to weld like that. It works like torch welding steel, they sell sticks of matching plastic for filler wire. It's about the only way to do polyethylene, like Windsurfers.
    I'm researching glues, IPS has good glue, but very expensive. At $17.50 for a 50ml tube and $47.50 for the applicator pump, it gets costly quick. I checking with a British company for comparison.
    The big hassle is some of the glues are flammable, and the post office and airlines won't ship them. UPS and my shippers charge extra for hazardous content.
    I've found some glues that are not flammable, concentrating on them.

Here is some info with regards to materials, enjoy:

And the polyester/neoprene fabrics that Goodyear makes are double ply so are very heavy by modern standards.

100/yd? whew... that's very expensive... But, there's no alternative. We can't have a leaky blimp, that would mean ridiculously frequent gas replacement and its associated extreme impracticality.

I had no idea that the most expensive part of the blimp would be the lift bag material, but I guess that's the case by a wide margin... still, if you scrimp (wisely, without disregarding safety or anything like that) on other things, it could still come in under 10k, even with 6k spent on lift bag material. No wonder the project's stated price goal is 10k, before I learned of and came to terms with the price of expensive synthetic balloon-plastic, I believed I could go much much cheaper, maybe about 4k. I had no idea about this.

Maybe I'll have to use a single lift-bag configuration after all. I knew that worse surface-area to volume ratio decreased lift efficiency, but with surface area at such a premium, the case against a multi-bag configuration becomes even stronger.

...Anyhow, on a different note, I've learned that if you plan on using a mere OTS consumer fan as a propeller, size doesn't matter so much as rpm's. What you want in that dep't is a "high velocity" fan with a light head which can be easily detatched from its stand without upsetting the wiring.

I looked at fans a couple days ago at a hardware-ish store and found a medium size fan on a stand. It looked like the head was would easily rip off and it put out a lot of force. I figured I could get maybe 5-8 knots out of a pair of them. I didn't check the specs but I believe it was about $180, that's affordable.

Weigh the fan. Hang it from the ceiling with two strings side by side with some separation( to keep it from twisting). Turn it on. Measure the angle it attains from the vertical. The weight times the sine of this angle is the thrust it puts out. If it swings between two angles, average them.

Caveats:

Don't do this near anything breakable including yourself. ( Have someone near who knows how to dial 911)

Don't do this if you're near drunk.

Don't blame me if you get hurt, I didn't make you do this.

Send me the results of your experiment so I can compare to the post I had on fans vs. props.

Start off on low speed and work your way up.

If the fan moves violently, add weight and try again.

I didn't buy it... I have no money :(

I just tried it out in the store...

But, good idea for future reference. I'll try to remember it.

Tell the store you're a real interested customer and see if they'll do the experiment for you.