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Oct 04, 2008, 08:15 PM
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Lee, I haven't done the float thing before, but since you used a 7" prop I decided to try this on my small NB delta which also uses a 7" prop. It will toot along in a parking lot. I was surprised how quickly it would turn and didn't dare stay on the gas to long as it kept wanting to flip in the gusts with a little too much zip in a cross wind as my son and I were just using the rudder as an air car. It will just sit there doing donuts almost like a pivot was placed under the nose. Thrust is not "UP" enough yet and its dark and 25mph gusts. I wonder if my skids and front nose piece are too big...and may affect flight. What do you think? Of course in the air will tell. If a true snowball, it would be a 17" diam. Perhaps I should lose the tail skid that I did have for the wheeled gear. I could then lose 1/2 to 3/4 on the height of the skids (2.5" now). The original fuse is 1" x 1" epp as well. The fuse clearance is 1.5" and the prop clearance is 2.25" So dropping even .75" of skid height, I wouls still have .75" fuse clearance and 1.5" prop clearance. I set the motor height at 3" above the wing. On grass, this just wants to dig in, but this was rather fun just as it is in the parking lot. Thanks
Last edited by tymbrewolf; Oct 04, 2008 at 09:09 PM. Reason: added clearance heights
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Oct 04, 2008, 10:29 PM
Lee
Lee
PERFECT LANDING !!!
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Thread OP
Tymbrewolf

You have a totally different design that is going to have unique characteristics.

A couple of questions.

Will your plane sit with the tail of the plane on the ground? In other words will it rotate to take off? It won't take off if it is running flat. The leading edge has to be up about 2" above the tail to get enough wind under the wing to get off the ground. The trick is you put the back of the float at or up to 1/2" behind CG to make it so it can rotate better. A wider width of the floats makes it stable on the ground and seems to trap more air and make it fly better.

How much does it weigh with and without the radio and battery? How many square inches of wing area do you have? The Snowball is 24" in diameter That makes it 3.14 square feet of wing. It is not a small plane. A larger wing span is important especially with a top mounted motor if you have an unstable plane.

Wing loading is critical on flatfoam planes. The Snowball is over 5 oz/square foot. I thought that was pretty good considering it is made out of 1.9 lb EPP but it would fly better if it weighed less. Many flatfoam planes are built out of Depron and fanfold to keep the weight low.

If you are flying it RET (rudder, elevator, throttle) Do you have enough polyhedral in the wing to make it controllable.

What is the angle of the motor compared to the wing? This angle is always something that has to be figured out by trial and error. I start with an educated guess and then try changing it and finding the best angle. If you are following the "Q-plane" thread my first video is just that as I launch the Eagle and would adjust the elevator trim and the motor angle for best performance.

I have learned the Nutball is not an accident. The engineering is sound. The Capricorn engineering is also sound. I have learned that there are some things you can play with and some things you can't. I have flown similar planes to both of these that did not fly well at all. I have not liked flatfoam planes in the past.

My first attempt at a Snowball was so bad I sawed it up when I got home and erased the pictures. That being said I have also had planes that didn't initially fly well that I kept tweeking and rebuilding until I worked out the bugs and got it flying well. The Snowball is a good example. For example I had no way to determine motor angle but trial and error. I think that what makes it fly as well as it does is it's size and my past experiece with seaplanes and floats..

My son has come up with a couple of changes that will save weight and improve strength. He thinks that my plane is too heavy and a little redesign of the floats might help ground performance. A couple of other builders also have given me some suggestions that I think are good ideas so even the Snowball is evolving.

The Snowball is fun to fly. I love buzzing around the grass and taking off at any time with a bump of the elevator. I have learned to fly it upside down even though it wants to turn itself right side up. It is tough enough I will take it where I won't take other similar planes. It is worth building and is a fun plane that so far has gone with me every time I have flown since I built it. I have several more in construction.
Last edited by Lee; Oct 04, 2008 at 10:48 PM.
Oct 05, 2008, 12:55 AM
flyin' fool
goldguy's Avatar
Lee:

Thanks for the compliment and your right, the NutBall was no accident. Your SnowBall is a great V2 idea and will allow the wing platform to be flown off water, snow or as the video shows.......rocks. Gotta love it.

After many doodles and doin' the math, figuring out the prop, motor, target weights, airframe shape/area and wing loadings, I started slicing up foam. Notice that I first mentioned the prop, because that's where I start...small prop for fast, big prop for slow, then motor KV and the required battery, weigh everything need to propel the chunk of foam into the wild blue and then set a target weight for the airframe. Wing loading is everything and the weight to thrust ratio is what makes it all fun.

My prototype 17" NB flew off the building board without needing too much teaking. Just to make sure it just wasn't me, I got others to test fly it, then made another 20" span version and again recruited testers. When I new I had a winner, I then posted the design knowing anyone could build this simple design without any fiddling around and have a ball flying it.

Nice to see someone taking it to the next level.

Frank
Last edited by goldguy; Oct 05, 2008 at 10:19 AM.
Oct 05, 2008, 03:17 AM
D'oh.. Dumb Left Thumb
dekan's Avatar
How time flys...has everybody forgotton the father of the Nutball, https://www.rcgroups.com/forums/show...5&highlight=R1
Oct 05, 2008, 04:58 AM
7up
7up
,ɯǝ ʇoƃ ɐʎ ɟı ,ɯǝ ǝʞoɯs
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@dekan

If ya gonna go there you may as well go back to the UFO or Hoot.

There are alot of designs focused around the circle flier but all seem to have their own unique flying characteristics.
Oct 05, 2008, 05:12 AM
D'oh.. Dumb Left Thumb
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Thanks 7up, for the reminder on the other possible ancestors..IMHO the Hoot has more claim to be the originator than the UFO.

We all know that Goldguy has done a great job with his input into this type of design....

I just wanted to inject some history into why this type of plane is a great flyer...Its had quite a lot of work on it by a lot of people
Oct 05, 2008, 08:54 AM
Registered User
Lee, the NB Delta flies just like a Nutball except that it penetrates the wind better as a delta should and it takes just a little more throttle and is not quite as floaty. The nutball is probably still all around better in still air. In NW OK, there is never still air unless it is in 2am. I was going to get up and edit my post saying that my floats are back at 40% instead of the 25-28% where CG is. I was also going to ask about your floats at rest as it appears to drag on the elevator. I was concerned about the TE of the wing as the tips take abuse on dollar try foam as I have the little bamboo spars on the ends and packing tape on them as well.

And Dekan, yes we shouldn't forget the R1, nor the Sq2 or Gramps version. My prerunner Squirt flew as well as a Nutball too once I modified the dihedral from 17 degrees when Frank came with the totally round NB at 24 degrees which did speed up rolls. We also shouldn't forget Gene's or Glen's input. We continue to modify these designs. Just wait until you see my 4ch dihedralerons/rudder/elevator vtol NB Delta that will be coming this winter. I don't know of another current pylon engine mounted round RET on floats mounted to the wing. The snowball obviously has taken some independent testing as well which should be seen as a compliment to everyone that has had a hand, foot, or fingernail in its development. Enough about that.

Lee, I haven't weighed this. Although, my wingloading was pretty good prior to the floats. The epp is rather light. I will do my testing as yes there will be nuances that won't be the same. I just wanted need your advice on the use of your plyon mount and the basic float arrangement needed. I have considered honeycoming the floats for air pass thru on rolls. I would really like to see a side profile of your new floats. I would also appreciate a picture of your plane at rest from the side at ground level. The last thing is the clearance from ground to prop tip.
Oct 05, 2008, 09:45 AM
D'oh.. Dumb Left Thumb
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As I said Tymbre, a lot of people... you,Gramps and Box are definately on the list. GB and GPW are always on my list of top contributers

Lee with the skids/floats and the thrust line mod/Radio box has moved it up a gear.

As you say somebody else is bound to find a new wrinkle.
Oct 05, 2008, 11:00 AM
flyin' fool
goldguy's Avatar
If you go back to the beginning of the NB thread, I give credit to the R1 and the Sq2 for my inspiration. What motivated me to design the NutBall was, that they had the right idea, but not the performance I was looking, as I wanted something that would push the limits in flyability for a rudder/elevator design that had no tail.

The only other way was to go with no dihedral and elevons/rudder, and I had loads of those.

I think it's great to see what other do with morphing other's ideas, nothing stays the same, not like building kits or putting together ARFs. That's why the scratch build forms are so much fun and a good teaching tool for everyone.
Oct 05, 2008, 11:56 AM
Registered User
Lee, I need some advice on your pylon and skids as mentioned in #37. I really value the input. However, it is fine to do this in pms if you don't want your thread hijacked from the snowball to other plan forms utilizing these techniques. I really would appreciate the advice on CG/skid placement understanding, tail no skid/vs. skid, prop clearance, and side profile of the current better working skid. Which ever way is fine, I don't have many independent ideas as I am not an engineer. I have to rely on others for understanding. Thanks
Oct 05, 2008, 02:16 PM
Lee
Lee
PERFECT LANDING !!!
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Thread OP
What you have is very flyable but you have to work out the details to perfect it's flight. To me it looks like your floats are too long but I can't tell without a closer look. Your square float will work fine if it can tip back and you have enough lift.

Look at what others have done to fix the same problems then let it evolve. I never can build two planes the same my planes evolve so fast.

If you look at my threads and tutorials I haven't held back any secrets. I even show you how to cut it. Just copy the features of the Snowball. I will consider it a compliment. It is the best of what I have come up with so far that has been tested and proven.

My motor is a s low as I can get it and keep prop clearance. I have had the Snowball tip forward on the skis and hit the prop on grass and rocks even though I designed it with enough clearance on flat ground. I hadn't expected to be running it on the RC car tracks when I originally designed it so it needs to evolve.

It doesn't matter if the tail drags. Put a piece of tape or a skid back there if it worries you. The instant you hit the throttle all of the weight comes off the tail and the plane takes off so fast the tail is hardly on the ground. The plane cannot take off without a positive angle of attack. Watch airplanes at the airport or check out youtube and watch the planes taking off. If the floats won't let it rotate it cannot take off. Even boats have to rotate to get up on the surface. This rotation is critical on seaplanes.

Just put the back side of the ski at the CG. Take a saw and cut off the back side of you floats a little at a time until it does what you want it too. Believe it or not that is how I did it. Let her flop down.

A far as who designed the round plane ... I saw some RC round planes flying in the 80s and the military and that two prop version in the 40s and round wing monoplanes in the 20s and there are round seeds that have parachutes that have been around for millions of years.

Paper airplanes are flat wing planes and I was folding polyhedral into them when I was 5 years old. We were throwing lids of containers long before we had Frisbees. It's all just evolution.

We get a new idea and bend and mix and stir and cut and glue until we get something a little different and then everyone tries to say who invented it. I've said before there is really no new planes they are just evolved planes built on the shoulders of all of those who have gone before.

My one rule is I will never copy what someone else has done and not give them credit. When does it become mine? I'm not sure. Maybe never.

I have sincerely tried to give credit to the planes and designers that inspire some of my designs. Now I am not up to researching back and seeing where they got their designs unless they are incredibly unique. It is like doing genealogy and all that who begat who bit and all.

I'll be adding more to the instructions in the next two weeks when I get some breaks with work.
Last edited by Lee; Oct 05, 2008 at 02:29 PM.
Oct 05, 2008, 07:49 PM
Registered User
Lee, I weighed my plane. The orighinal LG version RTF weighed 156gr. I can't believe I lost 26g adding all that foam. But the new version is 130gr on the nose. 178.75sq" area give a wing loading of 3.71 which is very respectable. The 17g motor and 7x6 prop gives a thrust of 252 according to Lazertoyz (Dan's) testing giving a 1.9 to 1 thrust weight ratio which again should be rather respectable. I took 1/2" off of the height of the skids and glued some cred card (gift cards) to the bottoms. It does rotate up off of the tail immediately if that is what you mean. Still 25+ gusts today. I took off the tail skid to allow for rock. I tilted a little more up thrust on the prop mount. Won't go in grass...??? It just sits there if set in the grass.

Here are a couple of videos of scooting on the driveway. https://www.rcgroups.com/forums/show...52&postcount=1
Oct 05, 2008, 07:55 PM
Lee
Lee
PERFECT LANDING !!!
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If you look at the Capricorn Evolution Video we did, Chris had to give his plane a push, even with it wide open throttle, to get it started on the grass. He had a BW 1300 on his. When he upgraded the motor he could take off with less than full throttle and had a good climb out.

The Snowball takes full throttle to take off on grass with a BP21 equivelent motor and only about 1/3 throttle to fly so you are having the same drag problems we are. We found heavy packing tape or Formica on the skids to make it slide better.

I like to test prototype planes. It's like breaking horses. You're never exactly sure what is going to happen.

Have fun.

What I do like about living in the desert is all of the good weather we have.

I do intentionally design planes to be flown in the wind, if you haven't noticed.
Last edited by Lee; Oct 05, 2008 at 08:02 PM.
Oct 05, 2008, 10:15 PM
Registered User
Went back and read through the capricorn thread. I now have about 1.25" inch rock on the floats on my 16" long plane. Close to what you recommend. I knew something was wrong on my weight. Re weighed. As I thought it is a pig now at 182 so I added 26g instead of taking away 30g. Probably too much HG. Wingloading is not as good at about 5.16 oz/sqft.
Oct 06, 2008, 12:08 PM
Registered User
dbacon's Avatar
Wow Lee, you outdid yourself with this build string, great.

Blue foam sucks up water, as does pink foam, expanded bead polystyrene, styrofoam, and the only one I have found that I can use is Depron. I would love to find one that won't take on water, but just can't...


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