Make your own free website on Tripod.com
 Building Tips
 Home FAQ What's New
Home
Carbon Fiber Bellcrank
Carbon Gear
Control Horns
Lasercut Horns
Laser Horn Dimensions
Foam Wings
Building Tips
Resins and Materials
PVA Mold Release
Hi-Temp Prop Mold
FAI Team Trials
Links
Kid Venture
FCM
Pictures 1
Pictures 2
Picutres 3
Pictures 4
Pictures 5
Pictures 6

 

 

 

 

Plane On Gages

This is a picture of Chiros under construction. The plane is positioned on height gauges to assure dead on accuracy of all dimensions. The gauges set the engine crutch, wing, and stab incidence all at the same time. In addition to setting the incidence it also aligns the trailing edge of the wing and stab parallel to each other while keeping the fuselage centerline at 90 degrees to the trailing edges of the wing and stab. This is all accomplished by working off of the flat glass surface with reference marks to indicate the position of each component. The gauges hold each assembly in the proper position while they are glued together. There is a total of 16 wing and stab gauges and 1 engine crutch gauge and 1 fuselage support fixture to support the aft end of the fuselage. If there is a warp in any one of the components the gauge will pick up the discrepancy. The gauges are also used to align the wing halves while gluing the center section joint. All components have to be straight from the start to assure the plane is accurately aligned. A straight airplane starts with a straight edge and a straight sanding tool. It is a good idea to have a few 36 inch sanding bars on hand to true up the long edges of the balsa sheets. I always build off of a flat piece if glass that is 1/4 inch thick that is shimmed flat with paper. The glass sets on a metal table. The metal never warps like wood under different temperatures and humidity variables. A heavy metal office desk makes a good base on which to lay your glass. I have seen many fixtures over the years for wings and fuselages. These are important items of the airplane to keep straight and true but if you have a straight fuselage, wing and stab and you assemble these components out of alignment the plane will not fly well enough to be competitive. The alignment starts with a straight edge against the first piece of balsa and ends when the airframe is completely assembled.

 

Plane On GagesAnother view of Chiros on the gauges.  Note the triple beam gram scale in the top of picture.  This is a must for a light weight airplane.  It is also beneficial to keep a written record of your components to compare later.  I had someone show me a piece of aluminum arrow shaft that he said was lighter than a fiber glass shaft of the same outside diameter.  After setting equal lengths on the scale they were equal in weight, so don't always trust your judgment when it comes to weight.

 

This shot is of a wheel pant mold, plug and half of a fiberglass wheel pant. I took a wheel pant off of a discarded airplane and closed the wheel well. Since the pant was already finished I only had to touch up a few spots. Once I had the finish I wanted I waxed the plug or wheel pant,  built a dam around the part, which is where the parting line of the mold is created and applied PVA which is another name for polyvinyl alcohol. Once the PVA cured it was time to apply a tooling or surface coat to the part. When the surface coat was dry then multi layers of glass cloth were used to build up the mold. The weight of the glass pant was the same as the 5 pound balsa pant. The advantage of the glass part is they can be reproduced with a lot less effort. This is another subject that I will cover in more detail in the future.

 

Tip On Installing Hinges:  Ever have glue wick into your mechanical hinges? Try filling a metal jar lid with Vaseline or Petroleum Jelly, as it is sometimes called. Fill the metal jar lid with just enough Vaseline to cover the hinge barrel when the hinge is folded and dipped. Heat the Vaseline until it just starts to smoke. Fanning a propane torch under the lid for a few seconds is usually adequate to heat the Vaseline. Fold the hinge in half and dip it into the hot Vaseline, wipe off excess Vaseline on outside of hinge barrel and allow to cool. The Vaseline when heated will wick into the barrel and pin of the hinge. I have used this method and was able to demonstrate using thin CA glue on the hinges without hinge locking up. Vaseline works better than oil because it won't wick out of the hinge barrel and contaminate the tab of the hinge. It is a good idea to hold the lid with a pair of Vice Grips and have the Vice Grips secured in a vise. Even though CA will work for installing hinges in a non foam wing, it is better to use a slow drying 20 minute epoxy in order to give yourself enough time to align the hinges. I always glue the hinges into the movable surface first then after cure glue the surface to the wing or stab. It is easier to glue the flaps and elevator hinges in after the airplane and components have been painted. Before the epoxy has hardened and is still rubbery, pick the squeeze out away with a small screwdriver. Applying a little wax around the opening of the hinges allows the squeeze out to be picked away easier.

 

Steve Starrs Impact

Steve Starr's Impact on the building board or glass. Steve built a table with a 1/8 inch edge above the table to hold the Enviro-tech epoxy. The epoxy was poured on the surface of the table up to the 1/8 edge to create a self leveling flat surface. On top of this surface he placed a 1/4 inch sheet of plate glass. He works off of this level flat surface to create a straight airplane. The wing on this airplane is built using the lost foam method. Lost foam wings are available through Bob Hunt. Bob offers many popular designs using the lost foam method. Notice the height gage in the right side of the picture.

Starrs Impact

The finished product of Steve Starr's Impact shown above. Power is a OS 46 VF on a Werwage pipe. Finish is SIG MFG. dope, rubbed out with simichrome.

Starrs Impact Nose Section

The nose section of Steve's Impact.

 

 
Sanding ToolPicture of a sanding tool used to sand in the nose section to align with back of spinner. It is constructed of 1/4 inch lite plywood  and 1/8 inch regular aircraft plywood. I always had a hard time sanding in the nose section of the airplane to be parallel to the spinner back plate until using this tool. This tool allows you to sand the nose to the right depth also. When the engine is mounted, insert the shaft through the hole in the pad and sand by using a twisting motion. Once the counter sunk area stops against the thrust washer of the engine you are ready to glue in the plywood nose ring. If you have a 1/8 inch countersunk area on your sanding pad then you will be able to use a 3/32 plywood nose ring and have a 1/32 inch gap between the back plate of the spinner and the ply nose ring. By cutting the hole in the 1/8 inch plywood and then gluing it to the 1/4 inch base it saves you from routing out a countersunk area. 80 or 120 grit sandpaper works well for this tool.

 

Simichrome

One of the best products I have come across for buffing out an airplane. This product seems to be the right viscosity for hand buffing paint. As always it is important to first wet sand with 1200 or finer paper before buffing. Adding a few drops of dish water detergent to a bowl of water aids in the cutting action of the paper. When using ultra fine grit sandpapers make sure you don't store them with coarser grits. One a little pebble of a coarser grit gets stuck to a piece of 1200 grit paper it is enough to ruin your day. Along the same line, always wash or rinse the fine paper before using it.

 

Here is a neat little tool that I made. I wasn't the first person to make one of these plane holders but the thing sure comes in handy when painting or masking an airplane. The airplane is allowed to rotate 360 degrees around the threaded rod with a wing nut to lock the airplane in any position. The fixture also allows the airplane to swing side to side from the work bench. There are two mounting plates attached to the aluminum bar. You only need one plate when attaching it to your airplane. There are two sizes for different engines. The aluminum plates are drilled out to the motor mount lug dimension. The plate is then bolted to the engine beams while the shaft of the fixture is slid through the nose ring and attached to the plate. The aft end of the fixture is bolted to the workbench or C-clamped to a stable ladder. I believe Byron Barker makes a version of this fixture that is a stand alone version of this one. As the name implies, there is no need to attach it to a workbench since it has it's own stand. Byron Barker lives in New Albany Indiana and can be reached through the PAMPA directory.

 

This is a home made height gauge used to mark the centerline for the stab and wing on the sides of the fuselage and wing cores.  It is beneficial to extend the wing and stab centerlines beyond the trailing edge for a reference for the flap and elevator horn.  Before the top blocks or molded turtle deck is placed on the fuselage, the fuse is placed upside down on the glass while the wing and stab centerlines are drawn on the sides with this center line gauge.  The marker in the gauge has a super fine point on it.  The marker is replaceable and the height of the marker is adjustable by loosening the two 4-40 socket head cap screws.

 
This tool is not my idea but it is worthwhile repeating.  It is a hinge recess sanding tool that allows repeatable, uniform and exact hinge recess slots.  The sandpaper is glued to a piece of wood that is the thickness of the hinge barrel that you are using.  The sanding strip is then glued to a back stop that allows the sander to sand to the correct depth.  A strip of wood is then glued to the back side of the stop to act as a handle.

 

The mighty industrial vacuum pump.  This pump is used to vacuum bag composite laminates and wood laminates.  Future articles will cover the processes of vacuum bagging balsa/balsa ply laminates, carbon/balsa laminates and carbon fiber parts.

 

This pump is available from Aerospace Composites and works extremely well for the hobbyist.  The pump is lighter duty than the pump shown above but at less cost.  I have used this pump to vacuum bag balsa to foam with great success since the vacuum is adjustable down to eight inches of mercury.  Too much vacuum and the 1# white expanded polystyrene will crush.

 

 

 

 

fbcounterleft.gif (1012 bytes)

Hit Counter

fbcounterright.gif (1065 bytes)

Web site managed by Dan Winship.
Copyright 2002 Winship Models. All rights reserved.
Revised: August 31, 2003.

Back Home Next