TRIPOLI
PITTSBURGH WORKSHOPS
- March 6th 2010 -
ATTENDING: Jim Callahan, Dave Rose, Tom Blazanin, Joe Pscolka, George Pike, Christine Rial, TR Garmin, Kevin Wuchevich, Chris Pearson(OH) and Dave Cooper(OH)
Great weather on the 14th may have driven many member to other family oriented things but those member attending the WorkShop got a really great day of rocketry. Joe led the group with a hands on demonstration of making a nose cone via the wrapped foam method. Starting with a stack of foam blocks Joe explained the the homemade jig used to rotate the foam while a router traced a pattern producing a shaped plug. The importance of alignment is important and getting the foam shoulder of the nose cone to mate up with a piece of airframe being used is probably the most critical operation.
Once the nose cone shoulder was matched with the piece of airframe the rest is a simple follow the pattern procedure.
 Joe explains the piece of airframe required to base the shaping procedure |
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 Lower template alignment is critical to the operation |
 Chris & Christine view the shaped foam. Another foam block shows before and after. |
 The wooden tip is also shaped with the router. Do not cut it loose yet. The whole piece needs sanded to remove noticeable ridges. |
 TR holds the final shaped foam plug which will be wrapped with several layers of fiberglass |
The next step was to remount the plug, with the piece of airframe secured, and mark a line on each side of the foam shape, running through the center. Two layers of glass cloth is then laid on one hemisphere of the cone. When this is beginning to harden the cloth is trimmed along these two lines giving you half a nose cone laid up. The plug is then rotated 180º and the same is done to the other half.
With the foam plug now covered with glass it is rotated 90º and the same operation is performed. This time the "gaps", if there are any, between to two lay ups are covered over making a solid glass cocoon over the foam shape.
Most important during the glassing operation is the tip. The glass cloth is wrapped tight all the way to the tip. This is a near impossible task without the aid of an item called Peel Ply. Peel Ply is a polyester or dacron fabric that does not bond to the fiberglass. When applied and the glass hardens it can be peeled off relatively easy, leaving a smooth ready to sand finish. It also helps retain and compress resin into the glass cloth for a good solid cure.
 Joe shows how to wrap peel ply at the tip to draw and hold everything to a tight point shape. |
 Clothes pins or small clamps are used to hold the peel ply tight and firm.. |
Tom presented his nose cone project created using a two piece mold method. This is ideal for making several of the same nose cones. Starting with a wooden nose cone used as a plug he demonstrated how he created the two mold halves. With the mold halves created the next step was the laying up of the part, which, while complex, is still very easy to accomplish. All questions were answered and note was given that his whole procedure was documented on the CD which everyone received.
 Tom explains setting up the wooden nose cone plug for making the half mold |
 Using the mold halves Tom explains the lay up process.. |
In addition TR presented his latest project working with his GPS system. Quite a work of art it impressed everyone attending.
Naturally Pizza was served and no one put drink's on Joe's machinery! The day ended with a motor demonstration (how else) by Chris and Kevin. Typical rocket people stuff that we all like to enjoy. This time around we were actually able to capture data on Joe's new test stand and data acquisition system. Click HERE to see an actual thrust curve captured on one of Chris' Kosdon Clone motors.
 Kevin's Wimpy Red 240ns performs well for his first time out.. |
 Chris in his usual full power on mode. |
No Work Shops were set for April as that is the month of our first launch. An Equipment Party is set for Saturday April 10th and all are invited. In closing we give you Chris' Full On Sparky Motor. See what you missed!!
