|Sep 27, 2008, 07:46 AM|
**SNOWBALL ** ATV-EPP-RET-LED**
We no longer sell the Snowball kit but there is enough information here to make one.
Enjoy these videos.
I like to move some of the different videos to the first post to keep them together so you don't have to go hunt for them. Look in Posts #2, and #14 for more videos.
Great seaplane flying by Russ40. Look at post 365.
Dave says he needs a 12 step program. Watch what he does to the Snowball in these videos. He puts the barn into barnstoming and the crash into crashtesting. See posts 387 and 394 and others. Check out his blog.
Another Dave with great aerobatics.
Russ took his Snowball to E-Fest, flew off water and flew indoors at work. He has posted many videos that show the what the Snowball can do He also made a gas version.
Nick is showing off some of the aerobatic snap rolls of his Snowball.
This plane is a cross between Larry's "Capricorn" and Goldguy's "Nutball". It's design was also greatly affected by what I learned when I did the Capricorn Evolution Tutorial.
Goldguy's Nutball thread - http://www.rcgroups.com/forums/showt...836389&page=94
Larry's Capricorn thread - http://www.wattflyer.com/forums/show...=26120&page=21
This is my Capricorn building tutorial - http://www.rcgroups.com/forums/showthread.php?t=898958
This Snowball is designed to fly in less than perfect weather. Proof of that is flying in the turbulent face winds on the mountain. It also can fly as gentle as a trainer. I trimmed it for level flight and it did four 100 yard circles without any radio correction. It flies well at half throttle even though we are at 4600 feet above sea level. I found that most RETs like to be right side up. Self righting planes are good for beginners because the plane will help level itself even in the wind. It will climb vertically WOT and harriers well. It will do both inside and outside loops and will do amazing snap rolls and spot landings.
I like to fly at night and the skis make a perfect stable platform for a night plane. I am planning to put a set of LEDs on the plane as I have done on my Capricorn Evolution modifications. The thin white EPP glows with minimal LED lighting. The LED lights will shine through the foam.
I like to fly indoors and this plane can fly slow enough to do it with class. The pontoons are slick on any surface allowing you to have both hands on the radio for take offs. The pontoons not only protect the prop but protect the building you are flying in from prop damage. The plane does enough slow speed maneuvers and aerobatics it is fun even in a small flying area for an experienced pilot.
If you are going to fly off water beware that EPP will soak up water and gain weight. So if you are going to build a seaplane or a winter snow plane you should use blue foam instead.
This plane could be built out of 1/4" fanfold or depron which would keep it lighter. A couple of carbon tubes would give it the strength it would need between the floats to support the motor. It's hard to beat the EPP foam however. I have abused these planes as can be seen in the videos and as of yet haven't even broken a prop.
If you want to use 1/2" foam, you can buy enough blue foam for 4 planes for about $12 at your local building materials store. The 1/2" bluecore comes in 1/2" x 4' x 8' sheets. Buying the 1/2" foam is also an easy way to build a plane if you don't cut or slice foam with more than a bandsaw or razor knife.
I try to design planes around an inexpensive power system. In this case a BP21 or a FC28-12 gives the plane vertical performance. This motor needs a 20-25A speed controller and I recommend at least a 3S 1300 mA lipo battery. You don't need an expensive radio with mixing. This plane is designed to fly well with a simple rudder and elevator set up.
For all of you kit buyers. Visit our store at www.crashtesthobby.com
The motor mount is also the radio box. It is 6" long and 2" wide. The front is 3" tall and the back is 2.5" tall. The prototype was 1/2" shorter but I had it mow the grass where we fly when the grass is longer wearing the edges off of my props. This is 5 degrees of positive thrust. If there is a secret to making this design fly well, this is it.
I also found that the plane would tip forward on the floats on landings in rough grass or gravel so I left the float flatter to help reduce the tip in the plane on landing. The original prototype had plenty of prop clearance but not in weeds, grass and rock. (I told you it is an ATV!!!!) Look at the new float design on the black and white Snowball in the photos below. There is a more detailed explanation in later posts.
This is a cross between the following two planes:
|Sep 27, 2008, 07:47 AM|
Building Instructions for the Snowball
This plane is easy to build but is no longer sold in a kit.
This plane is for a beginner or advanced flyer. It uses rudder elevator and throttle known as RET flight so your radio does not need to have an expensive radio with mixing to fly this plane. The floats or pontoons stick out the front and protect the propeller on rough ground.
The Snowball flies well in mild wind and has enough power to hang on the prop, harrier and do 3D maneuvers. It can float around slowly at 1/3 throttle. It gives beginners the advantage of having both hands on the radio transmitter for takeoff on grass or pavement.
EPP foam is one of the toughest materials that can bend, twist and will not crush. It is easily built and repaired with hot glue. EPP is so strong it is used in car bumpers. You will never want to build with flat foam or balsa again. It is cut with a hot wire cutter that adds more stiffness to the surface. It is normal to have some of the melt fibers left on the foam parts. Most can be removed by rubbing two pieces of the EPP together or picking them off.
The Snowball looks like a seaplane but it is not. All EPP foam will soak up water from lakes, snow and wet grass and the plane will get so heavy it cannot fly. Luckily the EPP foam dries quickly. Permanent markers will color the foam and not add weight. Be careful with paint and tape because it can add weight.
You will need the following to complete the plane:
• Radio and receiver. (Mixing is not needed.)
• BP21 or FC28-12 or comparable motor
• 7x4 or 7x6 propellers
• 3 cell 1300 lithium polymer (lipo) battery or comparable
• Battery charger
• 20+ amp ESC
• 2 mini servos Hitec 55 or 81 comparable
• Flight support equipment
• Pop bottle or milk jug plastic or Formica for bottom of the floats
• Low temperature hot glue gun and low temperature glue sticks
• Other glue options, Gorilla Glue, Shoe Goo
• Paint or permanent marker
As with all radio control devices the final user has to take responsibility for safe flying and practices with the use of this product and accessories. Our responsibility is to provide you the product as promised. Your responsibility is to have safe fun using it.
Please post pictures and videos of your Snowball on this thread. We want to see what you are doing.
Thank you for your purchase.
The following video is the maiden flight of the kit airplane. I'm not kind to it. I bang it around and try to break it and do things like ground loops, hard snap rolls, hard turns at full throttle and death dives to show you what you can really expect. Notice the plane can do all of this in a small softball diamond with trees around the edges. It is a perfect plane for small fields without a paved runway.
Mouse click on the star next to the volume at the bottom and it will go full screen. You can hit escape to get back.
This video shows the amazing ground handling.
This video is showing the indoor capabilities of the Snowball.
Here is a video of a 20 gm version.
Thank You RCGroups for a great site. It is a great place to have a Tutorial. One of my favorite things that you can do at this site is mouse click on any of these pictures to enlarge it for a better look at the detail.[/SIZE]
|Sep 27, 2008, 07:48 AM|
#4 SHAPING AND SLICING THE FOAM
If you watch the video the rest of the instructions will make more sense.
|Sep 27, 2008, 07:49 AM|
#5 DO SNOWBALLS HAVE RUDDERS?
This one does!!!
The pattern rudder shown here cut out of blue fanfold but the rudders on the Snowball can be cut out of which ever foam you cut the wing out of. The Snowball can be cut out of EPP, fanfold or blue foam if you choose.
Be aware that glue hot that can melt may melt again in a hot car or if you paint your plane black or build it out of black foam. I used Clear Gorilla Glue on the black foam to prevent future glue joint failier. I like white foam better.
|Sep 27, 2008, 07:50 AM|
#6 GLUE AND HINGES
I have been building both black and white EPP Snowballs using all three glues shown. The low temp glue gun is by far my favorite and the fastest of all. It only takes me 15 minutes to glue a plane together once the pieces are cut. I used the glue gun to make a glue hinge that is stronger than the foam. I hesitate to use low temp hot glue on black foam. One of my planes came apart sitting in the sun on a hot summer day. I have learned that painting dark colors over the glue joints can have the same effect as using the black foam. I fly with planes that have been built with hot glue all year around but I have also heard of people having the glue soften in a hot car so be aware of what can happen and take into consideration where you live when you decide which glue to use.
The Gorilla Glue was my second favorite. I followed the instructions and slightly wet the surface with a spray bottle and spread a thin layer of glue down the joint. The Gorilla Glue expands 400% and it did ooze out of the joint. I learned to watch it as it set and catch it just before it went hard. At this point it was easy to clean up the excess glue. I could roll the excess up and easily peel it off. The Gorilla Glue takes about 20 minutes to gel and several hours to cure.
I have used Shoe Goo on several planes. I glued a plane together and made a hinge with the Shoe Goo that works well on the black foam. I put a bead of glue down the hinge line and quickly spread it with a razor blade. The glue itself becomes the hinge and is quite strong. This is the glue recommended by some EPP plane manufacturers. I had trouble with one of my older tubes of Shoe Goo. It seemed to flow but didn't stick well. Make sure your glue hasn't dried out at all or you may be disappointed.
|Sep 27, 2008, 07:51 AM|
#7 CUTTING AND BENDING THE WING
Cut a 24" circle out of your favorite foam.
If you use a compass you will have a center mark. Draw a line through that center mark in the direction you want the motor to point if you have any preference with the foam. It usually doesn't matter at this point which is the front of a round plane.
Once the line is drawn you will need to draw two parallel lines one on each side of the center line 6" from the line. This will leave a 6" wingtip. These pieces of foam will be your wingtips.
You can either cut the wig tips off using a sharp razor blade and a metal straight edge. Or you can use a soldering iron like I did in the Capricorn tutorial and cut a "V" cut most of the way through the foam. The cut has to be wide enough that the foam can bend up 3" to make the wingtip. If you choose to cut the foam off and glue it back on you will need to cut the proper angle on the edges to make them fit.
The elevator needs to be cut off before you glue the with tips back on. The elevator is 4" deep across the back of the center section. It needs to be beveled preferable on the elevator itself so it can move with a hinge on the top of the elevator.
Now glue the tips back on making sure to get them at the proper angles. I found that if I have separated the pieces that I have better results if I tape the parts to be glued in position along the bottom of their entire length and then open up the gap and apply the glue then close it again and put weights on it as needed to set or cure. I remove the tape after the glue is set.
Put the elevator in position so that it will be able to move once hinged. Make sure you have enough clearance that the elevator will be able to move freely once hinged so it won't rub on the wingtips. On the top of the hinge line only put a small bead of hot glue or Shoe Goo and spread it quickly to a very thin strip along the hinge line before it can cool or dry. The glue itself will be your hinge. If you use too much glue it will bind up the hinge and not move freely. If you are using hot glue you can smooth out the hinge line with an iron at a low temperature and make it blend in well.
This is a clip from my blog about foam. I never did answer all of the questions that got asked but maybe this can help. I have cut a lot of different kinds of foam with a hot wire over the last 28 years.
White bead foam is still a good foam to build with. I wouldn't build a combat wing out of it but If I was going to balsa sheet the foam or vacuum bag it with fiberglass it would be the foam of choice. It is light, It is cheap. It is easy to get. It's easy to cut. It doesn't soak up water like EPP. It cuts very well and is what I use to test my new jigs to make sure they are working well before cutting the more expensive EPP foam. I used to build most of my planes out of it. It covers well with low temperature iron on coverings without the 3M77 or 3M90. Once it has a covering on it it does better than balsa in an accident and is easier to repair than balsa. Don't overlook it as a good building material. I have cut over 100 wings out of white bead foam.
Blue or Pink foam is 1/4 the price of EPP. It is strong and easy to cut. It is easy to find. It does dent more than white bead foam but if you heat it with a monocoat covering iron most of the dents will pop back out. I have built combat planes out of it. It doesn't crumble like the white bead foam in an accident. It doesn't soak up water like EPP so it is the best choice for seaplanes. It weighs more than the white bead and is close to the weight of the EPP foam. There are tricks to building that we use with the more brittle foams. I will put a carbon tube or dowel leading edge to prevent the denting you get with heavy use and I cover most of the white and blue foam planes. I have cut about 50 planes out of bluefoam.
Blue fanfold foam is a foam used to insulate foundations but it make a great building material. I still use it and recommended it when I designed a modification of the Capricorn. I called the Capricorn Evolution. I recently cut 28 planes out of it for our club. It is a great building material but sometimes hard to find. I am able with my foam slicer to slice thin foam if I can't find it at the stores. Another good reason to build a foam cutter!!!!
EPP's durability and repairability make it my foam of choice for many of my designs. I have cut over 500 wings and planes with this foam. I have cut many designs out of EPP that I don't cover but leave the raw foam exposed. It soaks up water so it is not the foam to use in a seaplane. It is the most expensive foam discussed here. It paints easily but has a waxy surface that won't stick to coverings without 3M77 or 3M90 adhesive. The 3M77 stays sticky and the 3M90 dries but still provides a good surface for iron on coverings. It can be hard to get. My mailman stopped and asked my wife what I was doing with all of the foam I was ordering. He asked if it was just styrefoam. I don't know why he was wondering. I only ordered 60 sheets of it in one year.
Most foams are not strong enough without some form of reinforcement like carbon tubes or rods or my old cheap wood dowel methods or sheeting or laminates. I will cut a grove in the foam with a soldering iron and then hot glue gun a tube in the wing. If I want the wing to be extra strong like the Q planes I will put a tube or rod top and bottom in the wing and it gets stiff as a board. Look at the photos in the bottom of post #1. The Q-trainer has a carbon tube on the bottom hidden in the black pinstripe. In combat planes like the "Assassin" I encourage the builders to add some reinforced strapping tape to critical areas to hold the plane together. A "iron on covering" adds a lot of strength to a plane. It does far more than make the plane look good and improve aerodynamics. I want you to see how tough the EPP planes can be.
|Sep 27, 2008, 07:51 AM|
#8 MOTOR MOUNT / RADIO BOX / SERVO INSTALLATION
The motor is tipped up positive 5 degrees. This means that when the plane is sitting flat the motor is aimed upwards. This is one of the rare planes to have this configuration but it makes it so the plane tracks well at all throttle settings. If you aim the motor straight forward or down the plane will flair when you cut the throttle and require re-trimming with each throttle setting. If there is a secret to this design...this is it.
Before you glue the foam block to the top of the middle of the wing cut a slot for your battery in the block so the battery will be secured between the wing and the motor block tight enough it won't fall out. Look at the pictures of the plane and see where we put the battery. Each brand of battery is a little different so you will need to measure and cut carefully. One one plane I cut the hole a little big so I now I have to put a rubberband around my battery before I stuff it in the battery hole to make it secure.
You also need to figure out how the best way is to fit your ESC and receiver in the motor/radio block and cut out the holes to secure these parts. The biggest problem I have had is the servo wires on the Hxt-900 servos are short enough they won't reach if the receiver isn't at the back of the motor pod.
It's not hard to do but take your time. For those I carefully draw the cutouts that will work with my radio on both right and left sides of the motor pod to make sure that both sides are the same. I then use a long box knife or a serrated stake knife and with a sawing motion cut the vertical cuts to the right depth looking at both sides then start evenly shaving the piece of foam out checking and rechecking the part fit until I have a snug fit that will hold the radio snugly without glue.
It only take me a couple of minutes to do the cut outs. I have done it so many times I know just what I want. I have all of my parts press to fit. It's really fast to change a battery with this method. Don't glue the pod on until you have the cutouts just the way you want them. It is hard to shape them after the pod is glued on.
Some of my batteries are bigger than others so on the small ones I put a #64 rubber band around them several times to make them fit tightly in the hole.
To set the angle I cut the EPP foam motor block 6" long and made the front of the motor mount 1/2" taller than the back of the motor mount. The front of the motor block is 3" tall and the back is 2.5" tall. The block is 2.5" wide. I kept the block square to make it easy to set up but feel free to shape it once the motor is attached.
The two piece motor mount in the photos was purchased at United Hobby, Hobby City or Hobby King (or what ever their name is this week) and is the bigger 44mm version.
You can see that the plastic base will slide into the secured part to the mount and it is glued into the EPP foam motor/radio block. This motor mount will also fit a BP21 or a BW motor 1300-1700 motor without the 44mm base. We have learned however that as a motor heats the plastic expands and we have seen the motor pull itself out of the motor mount so I have continued using the provided base and drill a pinhole and pin the motor mount together with an additional screw or just glue the motor mount into a single piece.
We have mounted the servos in the wing with the rudder servo on the left wing and the elevator servo on the right. They sit behind the motor/radio block of foam. It is easy to cut one servo hole and put both servos in it side by side. I hot glue the servos in place and warm them with a heat gun if I ever need to soften the glue to get them out again.
|Sep 27, 2008, 07:52 AM|
#9 ATV PONTOONS / SKIS / FLOATS / SKIDS
The pontoons are 3 inches tall 1.5 inches wide and 9 inches long. We recommend 2"-3" inches wide for water so the front of the plane will float higher. They serve as the floats for water, the skis for snow, the landing gear for pavement and they protect the prop, motor and battery in an accident.
The newest design on the float is 9" long and the back of the float is at CG which is 6" back from the nose of the plane. You want the plane so it won't rock forward on landing and damage the prop. A flat bottom float seems to work the best for rough ground and deeper grass.
In the prototype I designed in sufficient clearance for smooth ground but it didn't take long for me to be taking off of deep grass, rocks, weeds and uneven ground. I didn't have trouble unless the plane tipped forward on landing and hit objects poking up between the pontoons. To decrease the tendency for the plane to tip forward I decreased the angle on the front of the pontoon to make it square and thicker at the front to hold the nose of the plane higher.
The pontoons have to be properly designed so the plane can take off. The back of the pontoon should be at the center of gravity. Your plane needs to be able to sit with the tail of the plane on the ground so it can rotate to take off. It can't take off if it is running flat. If deep grass is holding the tail up so the plane can't rotate it will not take off either. The leading edge has to be up about 2" above the tail to get enough wind under the wing to get off the ground. A wider distance between the pontoons makes the Snowball stable on the ground, snow or water and seems to trap more air and make it fly better. If you are flying off water you need to increase the width of your floats to about 2.5" and use a blue foam that won't soak up water.
There is a lot of discussion about how to make the skids slide better. the foam itself will slide on some surfaces but requires a lot of power. Our original floats had 2" wide clear tape down the entire length which did work well.
The plane did not spend enough time on the ground to wear the tape out. We transitioned to fiber reinforced packing tape then Formica and soda pop bottle and milk jug material and some even found Teflon tape. You will need to put something on the bottom of the pontoon to make it smooth. Later experimentation showd that the pop bottle is the slickest skid on of the ones we have tried. It's cheap and most people have it around the house all the time. Pop bottle plastic is so slick that it is harder to glue especially because it will change shape if the glue is too hot. Experiment with some scraps to get the feel for how to glue the pop bottle material. Rough the plastic up with some sandpaper before gluing it on to help it stick. We have had to glue the plastic back on occasionally because it is so slick the glue has little to stick to. To glue it back on I reheat the old glue with a hot air gun or an old iron and press the plastic back into place until cool.
The pontoons are glued to the wing at the angles of the polyhedral and offer strength to the angle and help trap air under the plane. I did put a single 4mm carbon tube back 2" from the leading edge of the plane to help tie the pontoons the wing and the motor/radio mount together.
|Sep 27, 2008, 07:52 AM|
#10 TRIMMING AND FLYING
The Snowball flies with the elevator and the rudder neutral at 0 degrees. I surprised that it came out so well. The center of gravity is back 25% of the cord but this is not 25% of the wing area. On a 24" circle the CG is back 6" from the front of the circle.
The performance of the plane on the ground is dependent on how slick you can make the pontoons. In the videos you can see the plane sliding easily on pavement, rock and weeds and grass with Formica and pop bottle plastic on the bottom of the pontoons. The plane is airborne in a few feet and the skid is added weight when flying so keep them light. Deep grass can hold the tail up and prevent the plane from being able to rotate for take off. If you are consistently having rotation problems make the pontoons taller.
Double check your center of gravity. Do a range check on your radio and make sure the flight surfaces are going in the right direction. My elevator moves up and down about an inch but some people who fly it think that is too much and makes it too sensitive. The rudder moves also back and forth about an inch and a half in each direction.
Slowly give the plane throttle until it starts to move. If you let go of the elevator and it is neutral and the ground if flat the plane will start to slide about 3/4 throttle. Check out the rudder control and you should be able to turn both right and left. Let it build up enough speed to fly and then slowly pull back so you don't stall on take off.
Climb for some altitude and get the plane in flat and level flight and adjust the trims as needed to get it flying hands off at about 3/4 throttle. Due to prop torque on a round plane you will notice that the plane will trim a little different depending on how much throttle you are using but it has never been hard to trim or control. The polyhedral wing works well to bring the plane back to level flight. It fights being inverted but as you can see in the park video I can fly it upside down and still go into outside loops and rolls.
Landings are easy. With the skids you can land any where on most anything. The plane settles in easily at part throttle and can be driven on the ground back to you. On of the nice advantages of the pontoons is that they protect the propeller. In all the flying I have done with this plane I have not broken a single prop. I did wear one out cutting through tall weeds but that is to be expected.
I do not recommend trying an EPP version on water until we can figure out how to seal the foam. The EPP soaks up water like a sponge making the plane heavier and tail heavy and makes it near impossible to fly. This being said a blue foam version should do well of snow and possibly water.
|Sep 27, 2008, 03:40 PM|
Joined Dec 2007
Wow great video and the Snowball looks to be the perfect marriage between a Nutball and Capricorn.
Looking forward to more details and hopefully some plans. Curious about motor pod angle, prop etc
Great job Lee.
|Sep 28, 2008, 04:57 AM|
|Sep 28, 2008, 05:31 AM|
More videos to watch. Thanks to all who have posted!!!!
|Sep 28, 2008, 08:01 AM|
Joined Feb 2007
Lee, I am going to have to try those floats on a NB Delta to take off from grass. I guess I need to research Motor height to down thrust ratio such as does 1" above the wing centerline equal 1 degree down etc... I am sure this is here somewhere on RCG. With floats and the NB Delta shape, I may not even have to come back to RCG as that might be the perfect RET plane for wind and grass as it has the delta shape advantages of your capricorn with the NB benefits from Frank as well. To the grass landing end, I also liked somebodies big loop cable tie LG posted on the NB thread.