38 mm Saucer Build

[sailmike]

I currently have two saucers, a 29 mm and 54 mm. Flying the 54 mm on the K185 is awesome and would fly a dozen times a day if it wasn't so expensive. So, because of cost, I've decided to add a 38 mm saucer to my collection. It is being built the same way as the 54 mm. I choose to use cotton cloth instead of fiberglass as in the 54 mm for it's flexibility. A piece of scrap foam was laminated and found to have the perfect combination of stiffness and flexibility. The flexibility is needed to absorb landings, since this saucer doesn't have an active recovery system relying instead on aerobrake recovery. The 54 mm saucer is pictured in my avatar.

A sheet of leftover 1/2" insulation foam from the local hardware store was used. This same sheet was used to make the 54 mm saucer.

Here's the disc after cutting out the shape and the 'pie slice'. Notice that the thin plastic film was removed so the epoxy will stick.

The cone formed after gluing the two straight edges together and the cotton cloth to laminate it with in the background.

The cotton cloth laminated to the underside.

 

[Rocketjunkie]

I just flew 38 mm motors in my 54 mm saucer with an adapter. The saucer weighed about 3 lb.

 

[sailmike]

I've flown my 54 mm saucer, which weighs 1.25 lbs and is 20" in diameter, on a J350 with an adapter. The MMT is 9" long, which puts most of the 38 mm motors out of reach, because the CG has to be far enough forward for it to recover correctly. The 38 mm saucer should fly great on the new I49 or I59.

Here are a couple more pictures of the 54 mm saucer. For night time flights I like to fly it on the J315R. I've been thinking of flying it on the J540R or K695R, but I wonder if those motors may have too much thrust for my saucer.

 

[sailmike]

Got the top done now. It weighs 4.62 ounces. I think I could have gotten it a bit lighter by using peel-ply. I am hopeful that the final weight will be under 10 ounces or so.

Pictures:

 

[sailmike]

After deciding on how long I wanted the motor mount to be, I cut it to length. Next step was to figure out the angle between MMT and disc. I used a simple angle finder as shown in the photo.

This angle was transfered to paper and then to a piece of basswood and cut out. This template was used to cut out the 6 ribs with a hot knife. Here are the six ribs and the template.

The six ribs were laminated with cotton and trimmed.

Here they are being epoxied to the MMT with my little fin jig.

 

[sailmike]

After all the ribs were epoxied in place, the fillets were done with West System epoxy plus filler. The same epoxy and filler was used to glue this to the disc. These were clamped into place till the glue was dry.

The finished saucer!

And the underside. Only thing left is to add the lights for night flights. Total weight is 8.75 ounces, which is below my target weight. Yes! I49 will be my motor for the first flight, which won't be till January at the earliest. Hopefully I'll get a pic and post that here.

 

[dlb]

Need some LEDs for that critter?

 

[sailmike]

LOL! I could use some! Jack of "What's Up Hobbies" gave me a flashing necklace for free and I've taken it apart to lighten it. It uses 3 mm LEDs. What I'd really like is to be able to program LEDs to flash in a specific pattern using C++. What do you have?

Thanks,
Mike

 

[sailmike]

Finished adding the lights! They turned out brighter than I expected, probably because the batteries that were in the necklace were old and I put in new ones. The final weight is 9.8 ounces. I can't wait to fly it on an I49 or I59.

Here's a picture of the finished saucer and the wiring.

And a photo with the lights on. A video would probably show it better.

 

[terryg]

Need some LEDs for that critter?

Do you still stock them? They are not listed on your site anymore. I have some projects that could use 10mm LEDs.

 

[sailmike]

Thought I'd post a photo of my saucer fleet. The white one in the photo is a free download from Art Applewhite's site. I tend not to count that one as I never fly it anymore.