Prototype Skirt Inflated

Thanks to my helper Jenny today! We successfully inflated the test skirts using

We had to tape together 2 corners. Batten down the perimeter and then make a few tweaks to the starboard hull. (Note it's upside down and pointing into the garage so the starboard side is away from the camera.)

Inflated skirts

Here's the timelapse:



The skirts inflated and could take some weight resting on them with just the shop vac!


Lessons Learned

There were quite a few lessons learned today.

• The port side skirt ended up 2" too short, so the front had to wrap around.

Missed front port corner.

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• The front batten port most screw got started cross threaded, and I tried to force it. Unfortunately the weakest point in the system is the wood the tee-nut is threaded into and I ended up with the tee-nut spinning behind the batten. It took some forceful work with vicegrips to get the screw out. And now the threads in the tee-nut are shot, so I think I'll be grinding that section of the batten out and gluing in a replacement segment with a new tee-nut, since the corner is the most critical portion of the batten.

Cross-threaded

Adjusting the starboard side required a little scrunching:

Scrunched skirt under batten from shifting starboard skirt by 2 inches

Also the rear starboard corner does not quite line up correctly. When transferring the template we need to make sure to take this into account.

Corner length miss alignment. The port side was folder over to match.

Next steps:

Landing pads, to protect the skirt when landing.
Lift engine mount. I think I'll test it out of wood for quick fabrication and testing. Then move onto waterjet cut alumninum. I think the wood will be strong enough for initial testing.

Progress on Skirts

A big thanks to my parents who were in town and gave me a hand this weekend.

We made a bunch of progress on the skirts this weekend. Here's the timelapse:




A few details from the process. We are prototyping the skirts using drop cloth plastic picked up at the hardware store since it's cheap and readily available.

Thinking about how to secure the corners we ran into some zippers for tarps which we thought might be useful.

They did end up being useful, however we didn't use the zipper functionality. They turned into good adhesive tape. In the future I think I will do some research to find some good tape to use for joining the skirt elements. Certainly this tape is as strong as the skirt material. And it has a special zipper like anti abrasive rub surface ;-)



We experimentally determined the curves necessary for the joints using masking tape, the plastic and a shop-vac set to blow.

Prototyping with masking tape

The shape of this curve is quite complicated, and we learned the important part is that they line up, as well as the two pieces have the same linear length along the joint.

Two corners secured using zipper reinforced tape.

I also had not worked on the intake for the skirt at the front. So we added a crossmember under the lift fan to be able to catch the air and route it into the skirt.

Adding scoop area for filling the skirt from the lift fan.

We're not sure about the ratio of lift to skirt, but expect that we can adjust it with a baffle if we need more.

With the glue drying we had to stop work on the front skirt section. But once that dries the front skirt segment should be ready to go too.

Once I've verified the plastic skirt works as I like. i plan to cut it apart and measure it to make my templates for the rubberized vinyl version. 

Engine mount validation in vinyl

Thanks to Michael and David I have a vinyl cutout of the engine mount as measured. It appears that the through holes are too large and the one of the left is off by about 1 hole width. I'll update this again and either try to interate on the vinyl or else just print on some paper and cut it out.

Lift Engine Mount

I've been working on the lift engine mount a bit. I'm still amazed that there does not appear to be a library of these engine bolt hole patterns I can find. Or even specs.

Bottom view lift engine

Working with our measurements I've put together this design.

The layout sketch with dimentions.

 There was one redundant constraint and it ended within 1 mm so I think we're close.

A solid rendering

Michael's going to use his vinyl cutter so we can test the layout and if it works we'll work toward water jetting some aluminium.