Crazy Horse and Geronimo building instructions
Our 60" Geronimo and 48" Crazy Horse fly amazingly well in a wide range of conditions. Their construction is almost the same with their size being the major difference. The videos show a light weight build. If you are going to fly DS you need to build your plane for your location and the way you want to fly.
Our build instructions are in Youtube videos linked below. They will show you the building techniques of both the Geronimo and Crazy Horse. We sped up the video 4X to 6X to save your time. We put text with the video to help explain what we are doing and to help our non English speaking customers.
Flying wings won't fly tail heavy. We build with top and bottom fiberglass spars that oppose each other with an I-beam effect. The wing remains flexible until both top and bottom spars are installed. This makes the wing is more rigid than if it were built with arrow shaft or carbon spars. Fiberglass spars don't cause carbon fiber related radio interference. The wing has a straight leading edge meaning that the CG is going to be close to the front of the wing. Be aware of how much weight you add behind the CG.
The Geronimo CG is back 1.5", Spars back 2", flying weight 36-60 ounces
The Crazy Horse CG is back 1.1", spars are back 1.5" and flying weight is 24-48 ounces.
The planes built as shown in the videos have about 10 oz/foot wing loading. This is considered a lightweight build. I have flown a light build Crazy Horse in 40 mph winds and it flew amazingly well. We stress tested the wing to 20 lb weight bearing without wing failure with the spar system shown in the videos. The majority of the flyers will prefer the lighter build because most of us fly in light to moderate winds.
Build for the way you want to fly. High penitration planes have 15-20 oz/foot or more. Dynamic soaring records are all set with heavy planes. DS flyers fly in very specific locations in high wind. They add bidirectional reinforced tape layers and lead to intentionally make the planes heavy. They add more spars and bidirectional reinforced tape over the entire wing. They spread out lead weights along the leading edge of the wing rather in the center of the wing so they can be stressed to higher "G" forces. They use upgraded servos and linkages. Elevon movement is reduced with servo and linkage leverage maximized. The CG stays the same but is even more sensitive when the planes have higher wing loading.
Here are a few trick and tips that may help. Most of this is shown in the videos below.
Rubbing the EPP wings together will help remove any remaining cut fibers on the wing. You can also shave them off with a Bic type razor and pick stuborn fibers off with a fingernail. You don't need to sand the wingcore to get the laminate to stick but your laminate will look better if you remove all the cut fibers.
Why are are we cutting the wing slot in the fuselage bigger than the unfinished wing cores? Builders are finding that with all the layers of tape and laminate their wings no longer fit in the fuselage. If you find that your finished wing still is a little loose in the fuselage put a bead of hot glue around the joint of the wing and fuselage and it will secure it in place. If you still need to enlarge the wing cut out, make cuts in the bottom of the fuselage at the front and back of the wing and remove the bottom of the fuselage under the wing. This makes it easier to enlarge the opening so the wing will fit with minimal damage to the fuselage. Once you have the the wing and fuselage adjusted to the wing thickness, hot glue the bottom of the fuselage back in place then use bidirectional tape and laminate to strengthen the fuselage.
Use a new sharp razor blade when cutting EPP foam. Old blades can snag and leave rough cuts. Use a sawing action when cutting though EPP foam. Some long blade box knifes cut well, others do not. A soldering iron will cut EPP foam but is hard to get a smooth surface. Use a metal straight edge when cutting the spar slots with your soldering iron.
At customer request the Geronimo and Crazy Horse kits now have balsa elevons. Watch our build videos to see the hinging techniques. Bevel your elevons so the hinge line will be on the top of the wing making sure the elevon can go down. When using the balsa elevons I have been laminating the wing and the elevons separately. Leave a 1/8" gap between the wing and the elevon when taping. To make a hinge use a strip of 1" wide bidirectional tape top and bottom on the hinge line covered with 2" wide laminate to protect the tape. This makes a strong airtight hinge improving efficiency. Some flyers like the S tape hinges. Do what you are comfortable with but try to seal the hinge line.
Bidirectional tape does not need a spray adhesive to stick to EPP foam. We have found that the adhesive on some of the old bidirectional tape can dry out and may not stick as well as some of the new rolls of tape. Bidirectional tape is UV sensitive and can dry out and yellow especially if exposed to extensive sunlight. Try to laminate over the bidirectional tape soon after applying it to the EPP foam to protect the tape. The laminate we provide in the kits has a UV shield in it to protect the foam and tape.
The laminate provided in the kit does not need a spray adhesive. Its adhesive is activated at 180 F and the EPP foam starts to soften and melt about 230 F. If your iron is too hot, the laminate will start to shrink before it is ironed down and you will have wrinkles that you can't iron out. After I have laminated the wing at 180-190 F I go back and make a final pass over the laminate to do a final shrink of the laminate at 220 F. I found that clothing irons have better temperature control and heat management than hobby irons. Notice the iron I use for laminating in the videos. I use an infrared thermometer to check the temperature of my iron. We have found that the toe of the iron may not be the same temperature as the heel of some irons. We have also found that some irons will overheat if left sitting on the bench. I keep a wet rag on the bench to cool the iron if it appears to be overheating.
The entire build can be done with low temperature hot glue. The low temp hot glue is inexpensive, clean, fast and does not need cure time, drasticly decreasing build time and mess. You can work with the glue after it sets just by reheating it. You can see how we remelt the hot glue in the videos when we put the third spars in the wing. Bidirectional tape and laminate will stick to hot glue. Hot glue is not brittle like epoxy and Gorilla glue, both of which I have seen fail. We have flown for years in temperatures of 100 F or more and not had any trouble with the hot glue unless we put the plane on hot black asphalt or leave it in a closed car. Even then as soon as the plane cools the glue returns to its hardened state.
We recommend that you don't put black covering over hot glue joints, which is mainly over the spars, on the top of the wing to prevent overheating. I do have black stripes that cross the glue joints but they are limited. There isn't a problem with black on the bottom of the wing. If you are concerned with your local weather and temperature you can use a glue like Quick Grip which is also flexible and strong but not as fast or clean.
Build your plane for your location and the way you want to fly.
Our build instructions are in Youtube videos linked below. They will show you the building techniques of both the Geronimo and Crazy Horse. We sped up the video 4X to 6X to save your time. We put text with the video to help explain what we are doing and to help our non English speaking customers.
Flying wings won't fly tail heavy. We build with top and bottom fiberglass spars that oppose each other with an I-beam effect. The wing remains flexible until both top and bottom spars are installed. This makes the wing is more rigid than if it were built with arrow shaft or carbon spars. Fiberglass spars don't cause carbon fiber related radio interference. The wing has a straight leading edge meaning that the CG is going to be close to the front of the wing. Be aware of how much weight you add behind the CG.
The Geronimo CG is back 1.5", Spars back 2", flying weight 36-60 ounces
The Crazy Horse CG is back 1.1", spars are back 1.5" and flying weight is 24-48 ounces.
The planes built as shown in the videos have about 10 oz/foot wing loading. This is considered a lightweight build. I have flown a light build Crazy Horse in 40 mph winds and it flew amazingly well. We stress tested the wing to 20 lb weight bearing without wing failure with the spar system shown in the videos. The majority of the flyers will prefer the lighter build because most of us fly in light to moderate winds.
Build for the way you want to fly. High penitration planes have 15-20 oz/foot or more. Dynamic soaring records are all set with heavy planes. DS flyers fly in very specific locations in high wind. They add bidirectional reinforced tape layers and lead to intentionally make the planes heavy. They add more spars and bidirectional reinforced tape over the entire wing. They spread out lead weights along the leading edge of the wing rather in the center of the wing so they can be stressed to higher "G" forces. They use upgraded servos and linkages. Elevon movement is reduced with servo and linkage leverage maximized. The CG stays the same but is even more sensitive when the planes have higher wing loading.
Here are a few trick and tips that may help. Most of this is shown in the videos below.
Rubbing the EPP wings together will help remove any remaining cut fibers on the wing. You can also shave them off with a Bic type razor and pick stuborn fibers off with a fingernail. You don't need to sand the wingcore to get the laminate to stick but your laminate will look better if you remove all the cut fibers.
Why are are we cutting the wing slot in the fuselage bigger than the unfinished wing cores? Builders are finding that with all the layers of tape and laminate their wings no longer fit in the fuselage. If you find that your finished wing still is a little loose in the fuselage put a bead of hot glue around the joint of the wing and fuselage and it will secure it in place. If you still need to enlarge the wing cut out, make cuts in the bottom of the fuselage at the front and back of the wing and remove the bottom of the fuselage under the wing. This makes it easier to enlarge the opening so the wing will fit with minimal damage to the fuselage. Once you have the the wing and fuselage adjusted to the wing thickness, hot glue the bottom of the fuselage back in place then use bidirectional tape and laminate to strengthen the fuselage.
Use a new sharp razor blade when cutting EPP foam. Old blades can snag and leave rough cuts. Use a sawing action when cutting though EPP foam. Some long blade box knifes cut well, others do not. A soldering iron will cut EPP foam but is hard to get a smooth surface. Use a metal straight edge when cutting the spar slots with your soldering iron.
At customer request the Geronimo and Crazy Horse kits now have balsa elevons. Watch our build videos to see the hinging techniques. Bevel your elevons so the hinge line will be on the top of the wing making sure the elevon can go down. When using the balsa elevons I have been laminating the wing and the elevons separately. Leave a 1/8" gap between the wing and the elevon when taping. To make a hinge use a strip of 1" wide bidirectional tape top and bottom on the hinge line covered with 2" wide laminate to protect the tape. This makes a strong airtight hinge improving efficiency. Some flyers like the S tape hinges. Do what you are comfortable with but try to seal the hinge line.
Bidirectional tape does not need a spray adhesive to stick to EPP foam. We have found that the adhesive on some of the old bidirectional tape can dry out and may not stick as well as some of the new rolls of tape. Bidirectional tape is UV sensitive and can dry out and yellow especially if exposed to extensive sunlight. Try to laminate over the bidirectional tape soon after applying it to the EPP foam to protect the tape. The laminate we provide in the kits has a UV shield in it to protect the foam and tape.
The laminate provided in the kit does not need a spray adhesive. Its adhesive is activated at 180 F and the EPP foam starts to soften and melt about 230 F. If your iron is too hot, the laminate will start to shrink before it is ironed down and you will have wrinkles that you can't iron out. After I have laminated the wing at 180-190 F I go back and make a final pass over the laminate to do a final shrink of the laminate at 220 F. I found that clothing irons have better temperature control and heat management than hobby irons. Notice the iron I use for laminating in the videos. I use an infrared thermometer to check the temperature of my iron. We have found that the toe of the iron may not be the same temperature as the heel of some irons. We have also found that some irons will overheat if left sitting on the bench. I keep a wet rag on the bench to cool the iron if it appears to be overheating.
The entire build can be done with low temperature hot glue. The low temp hot glue is inexpensive, clean, fast and does not need cure time, drasticly decreasing build time and mess. You can work with the glue after it sets just by reheating it. You can see how we remelt the hot glue in the videos when we put the third spars in the wing. Bidirectional tape and laminate will stick to hot glue. Hot glue is not brittle like epoxy and Gorilla glue, both of which I have seen fail. We have flown for years in temperatures of 100 F or more and not had any trouble with the hot glue unless we put the plane on hot black asphalt or leave it in a closed car. Even then as soon as the plane cools the glue returns to its hardened state.
We recommend that you don't put black covering over hot glue joints, which is mainly over the spars, on the top of the wing to prevent overheating. I do have black stripes that cross the glue joints but they are limited. There isn't a problem with black on the bottom of the wing. If you are concerned with your local weather and temperature you can use a glue like Quick Grip which is also flexible and strong but not as fast or clean.
Build your plane for your location and the way you want to fly.
Crazy Horse and Geronimo build video instructions with new info in video #2
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Geronimo build video with similar techniques to Crazy Horse
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