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Joined: 1/14/2002 From: San Jose,
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Some people were curious about vacuum baggers.
This is my home made vacuum bagger. Capable of pulling 25" of Hg. We've since made some others with larger chambers (PVC tube) and improvements. Basically, it consists of the following:
Vacuum pump Chamber/reservoir Vacuum switch Solenoid/check valve Vacuum gauge Tubing A/C power switch and wiring
Basically, the vacuum switch has a setting that allows you to acheive the desired amount of vacuum. When the switch senses a 2" drop from its setting, it opens the solenoid and turns the pump on until it reaches the setting. Instead of a solenoid that blocks the reservoir from leaking back to the pump, some people use a check valve. I was able to buy all the necessary parts (pump, vacuum switches, etc) at a surplus store and got the rest at the local hardware store. Total cost on average if you can find the right stuff at good prices ~$50 - $75
Michael
< Message edited by Mluvara -- Jun 4 2002 4:37PM >
Posts: 1425
Joined: 1/14/2002 From: San Jose,
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Quick update for 6/5/02
Pulled the wing halves out of the bag on Tues evening. Came out great! Much better than last time so far. I believe I mixed up 12 oz of epoxy and used approximately 8oz in layup. It's hard to tell because a lot is soaked into the roller, excess glass, and still in the three paper cups I put it in. Plus, the excess that is pulled away by the peel ply is hard to account for.
Last night, I cut and laid up the spar material and put it in the vacuum bag. It's 3/8" end grain balsa with 3oz cloth bagged on each side. Next step is to prepare the landing gear area ribs (they will be much lighter this ime), lg rail supports, etc and install the main spar, along with some sub spars. Should have the mold closed up by the weekend and I hope to be grinning when I pull it out of the mold....
Remember, I said that I thought a 12 oz reduction was possible with this new layup. Last wing was 2lb 7 oz (very heavy!) Let's see if I meet my goal.
Michael
< Message edited by Mluvara -- Jun 9 2002 6:03AM >
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Joined: 1/14/2002 From: San Jose,
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6/6/02 update-
Took spar out of the bag last night and rough cut it to shape. Trimmed/sanded flashing on wing mold from layup and prepped for joining. Started cutting out landing gear ribs/plates for retracts and center wing rib.
Left to do: Cut out sub spars for near ailerons/flaps Glue in spars and landing gear areas Cut/glue wing mount blocks
Posts: 1425
Joined: 1/14/2002 From: San Jose,
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6/6/02 Update
Glued main spar in place along with sub spars near ailerons. Center rib also glued in place to prevent any possible crushing of the center section. Sanded landing gear ribs.
Posts: 1425
Joined: 1/14/2002 From: San Jose,
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6/8/02 Update.
On 6/7 I was able to install the landing gear mounts, ribs, etc and close up the mold!
I pulled the wing out this morning (6/8) with great anticipation of improvement over the last wing. I tried a wax instead of a wax/PVA mold release combination and it worked fantastic. I was shooting to reduce the wing's weight by 12 oz and used AAA contest balsa, less glass, lighter glass, and thinner ply on the landing gear mounts....
So... results are in!
Old wing = 2 lbs, 7oz (ugh) New wing = 1lb, 12oz = total reduction of 11oz! Not bad!
So, the wing came out well and construction begins on the fuse tomorrow (hopefully).
I was able to primer my brother's Tsunami and his should see paint by next weekend.
Here's a photo before I closed the mold up. Spars are in place, along with lg area and center rib.
Posts: 1425
Joined: 1/14/2002 From: San Jose,
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Wing out of mold with flashing trimmed. Black area is where I put carbon fiber to reinforce the areas where pressure will be put (wing bolts). I have to say that practice and diligence certainly helps when molding! I'm making progress learning this and it is rewarding to see improvement.
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Joined: 1/14/2002 From: San Jose,
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Thanks for the comments guys. I'm happy to share my work. Sorry for the lack of updates this week. Work and other duties have been pestering me. We will paint Chris's Tsunami this weekend and I will begin layup on a fuse for myself. Looks like I found an engine for my plane and hopefully all will be in order. The new wing is holding up well, albeit I've found some problems with what I used for the surface coat. I took the wing with me in my truck to the field last weekend and obviously, the temp is elevated in the cab. I noticed that the paint bubbled a little in some areas. Could be the resin postcuring or the paint. But, nothing bad. Both landing gear ar mounted. Next, it's time to cut out the flaps/ailerons and start rigging them.
Posts: 1425
Joined: 1/14/2002 From: San Jose,
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Layed up my Tsunami fuselage tonight. Started cutting glass around 8pm. Finished at 11:30 when the vacuum bag was sucked all the way down. If it wasn't for the phone ringing and well, basically running out of epoxy, it would have been an hour less. Note to self - make sure that you have enough epoxy next time! I forgot that the gallon of epoxy that I have used for making fuselages the past 2 years is finally gone! So, what did I do, you may ask? I improvised by using another brand for the last three oz. (two separate batches mixed)
Anyways, here's a series of photos.
Laying out and cutting the aeromat (core material)
< Message edited by Mluvara -- Jun 15 2002 7:06AM >
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All Forums >> RC Airplanes >> Pylon Universe - RC Pylon Racing >> Scale Racing >> Tsunami - composites, part 2 
Tsunami - composites, part 2 - 
Tsunami - composites, part 2 - 
