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Old Jan 18, 2013, 10:29 PM
more balsa please!
dcloin's Avatar
Princeton, In
Joined Jul 2007
793 Posts
Great looking and flying plane. I like the how it fits in the case.
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Old Jan 29, 2013, 09:58 PM
For us He died, in me He lives
Jimmy JFlyer's Avatar
United States, MI, Saint Clair Shores
Joined Dec 2008
5,121 Posts
Hi Slebetman, this guy is awesome. I am a foamy scratch builder but with the thought of doing classes for kids at church and also my young kids I started looking at FF rubber powered planes like the Delta Dart and such. I don't have much free time right now so all the foamies are sitting. But then I come across this and the thought of FF rubber powered in the family room is just too cool to pass up.
I have never done a stick & tissue or anything similar before but now am excited to try it.
Would you be able to give a materials list & maybe short build log?
I will do some easy kits first to get some stick build time before trying something like this. I am sure its got to be trimmed just right and the angles just right to perform like your does.

Any words of advice?
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Old Jan 30, 2013, 12:06 AM
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Malaysia, Selangor, Kajang
Joined Jun 2009
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Quote:
Originally Posted by Jimmy JFlyer View Post
But then I come across this and the thought of FF rubber powered in the family room is just too cool to pass up.
I have never done a stick & tissue or anything similar before but now am excited to try it.
Would you be able to give a materials list & maybe short build log?
I will do some easy kits first to get some stick build time before trying something like this. I am sure its got to be trimmed just right and the angles just right to perform like your does.
That's great. I was a pure foamie guy too. In fact I built several foam rubber powered planes before I started working seriously with balsa. Foam is still quite a good material but it's hard to get the weights I'm getting with balsa using foam. This plane for example is only 1.2g minus the rubber. And that's with the heavy plastic prop.

Materials list:
1. 1mm balsa for everything. I'm using cheap balsa from the art shop that architecture students use to build 3d models of buildings. If you have good light balsa then 1/16" should do just fine. 1mm is roughly 1/24" btw.

2. Covering is thin vegetable bag from the supermarket or grocery store. Just pocket a couple extra bags the next time you go shopping. An alternative is saran wrap/clingfilm but it's a bit heavier and much harder to work with because it clings to everything.

3. Metal bits - prop shaft, prop hanger & tail hook - No2 guitar string. They're cheap so get a few because you're going to waste a lot the first time you try to make the prop hanger and prop shaft.

4. Prop - thin plastic cup. The kind they sell bubble tea in. Some of the cheaper ones are thinner and lighter.

5. Glue - CA/superglue. I use the cheapest I can get my hands on. This is the one big difference between balsa and foam. Foam is cheap but foam glue can be quite expensive. Balsa is expensive but the glue is cheap.

6. Rubber. This is the only thing that you can't skimp on. Get good quality free flight rubber. The traditional vendors are:

http://www.shortysbasement.com/
http://www.faimodelsupply.com/
http://www.a2zcorp.us/store/

A plane that flies for 15 seconds or so with regular rubber bands will fly for more than 2 minutes with good rubber.

I'm flying my plane with .040 rubber but get yourself several sizes since selecting rubber thickness is part of trimming a rubber powered plane. When I started out I had only two thickness of rubber: 1/8" and 1/16" so I did the opposite: I tried designing planes that would fly well with the rubber I had.

Eventually you'll want a rubber stripper so that you can optimize the rubber to your plane but they tend to be expensive. The next best thing is to find a friend with a rubber stripper, which is what I did ;-). The next best thing after that is to simply buy rubber in a bunch of different sizes.

Now, some tips I've learned from experience.

I've accidentally found that 10" wingspan is great for living room flying. There is actually an official AMA class that is called the Ministick that was intended for living room flying and the maximum wingspan for the class is 7".

Give your plane plenty of dihedral. It's not for stability - at least not what you think. It's for spiral stability. Not enough dihedral will cause your plane to spiral to the ground on launch.

Don't use the rudder to turn. Instead, tilt the horizontal stabilizer in the opposite direction of the turn. Or looking at it another way, tilt the wing into the turn. Basically pre-bank the wing. As the rubber winds down and the plane starts to fly slower the rudder completely loses effectiveness. What happens if you trim to turn using the rudder is that the plane will start flying straight when it comes down which will cause it to hit a wall.

Give the wing on the inside of the turn (the left wing for left circles) some wash-in. This increases the lift in that wing allowing you to trim your plane to fly tighter circles - which is what you want if you want to fly in your living room.
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Old Jan 30, 2013, 08:47 AM
For us He died, in me He lives
Jimmy JFlyer's Avatar
United States, MI, Saint Clair Shores
Joined Dec 2008
5,121 Posts
Oh this is awesome! I am so excited to just tinker with something new. Thank you sooo much for the advice. I want to print what you said and hang it on the wall! lol
There is a couple hobby shops in my area that have most if not all of what I need. One shop is just plane stuff. It's such a candy store. So I shouldn't have trouble getting what I need to do this right. Only thing I will have trouble finding is the time to do it. lol

I plan on doing the Delta Dart with my daughter as my intro into rubber powered and maybe a couple others to get my feet wet. But I will have a hard time resisting not just jumping right in on this one.

Thx again for your help.
Jimmy
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Old Jan 30, 2013, 06:04 PM
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ColinNZ's Avatar
Auckland New Zealand
Joined Aug 2004
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Sorry posted in wrong thread
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Old Jan 30, 2013, 08:45 PM
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slebetman's Avatar
Malaysia, Selangor, Kajang
Joined Jun 2009
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Quote:
Originally Posted by Jimmy JFlyer View Post
Oh this is awesome! I am so excited to just tinker with something new. Thank you sooo much for the advice. I want to print what you said and hang it on the wall! lol
There is a couple hobby shops in my area that have most if not all of what I need. One shop is just plane stuff. It's such a candy store. So I shouldn't have trouble getting what I need to do this right. Only thing I will have trouble finding is the time to do it. lol

I plan on doing the Delta Dart with my daughter as my intro into rubber powered and maybe a couple others to get my feet wet. But I will have a hard time resisting not just jumping right in on this one.
The Delta Dart is a great flying plane. Another you should try after that is the Squirrel. The squirrel is particularly interesting because it has absolutely no dihedral and yet flies very well. It uses winglets to achieve a dihedral effect.

Do you know hippocketaeronautics.com? They have an extensive plan gallery but you need to register to download the plans. Register anyway. The guys there are cool. You'll even see some familiar faces/names on there. Also, read through the build logs. Very informative. They're not as high traffic as RCGroups but most of the time if you ask questions there someone will respond.

With regards to my advice. Don't take them too seriously, I'm still learning myself. Take my tip about the stab tilt for example. It's not absolute. Some designs do turn well with the rudder. This portable plane for example. The rudder alone doesn't work well but stab tilt + rudder works.

Part of the reason I've started doing rubber powered planes is that the projects are quick to do. Especially at these small indoor sizes. I don't have as much time as I used to to build RC planes.
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Old Jan 30, 2013, 08:48 PM
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Malaysia, Selangor, Kajang
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Oh, if you're looking for kits I can recommend the Ikara Junior. Most of the guys I fly with have either it or the RTF version the Butterfly. It's a very well behaved living room flyer with very consistent performance.
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Old Jan 31, 2013, 11:37 AM
For us He died, in me He lives
Jimmy JFlyer's Avatar
United States, MI, Saint Clair Shores
Joined Dec 2008
5,121 Posts
Hey, again thx!
I'll check out that site. I have already watched a bunch of vids on You Tube and have seen quite a few build how-to's of the Squirrel.
I agree with the time thing. That's about exactly my situation, then I see how quick and easy (in comparison) little rubber powered kits and builds can be.
Tho I have already started drooling over some of the more involved planes like the classics and WWII warbirds. Oh those look awesome. I know I will get into those when time permits.

Take a peek at the plane in my avatar. Its the J-Bug I designed a few years back. I am thinking it would be a good candidate for rubber powered. Even an itty bitty for the living room. The wing is just a great workhorse as far as lift goes. Mighht work.
Here's a link...
http://www.rcgroups.com/forums/showthread.php?t=1151461

I can't wait to check out the other planes you mentioned!
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Old Jan 31, 2013, 10:36 PM
For us He died, in me He lives
Jimmy JFlyer's Avatar
United States, MI, Saint Clair Shores
Joined Dec 2008
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So I have looked at a lot of "living room flyers" and I am wondering just how the prop/rubber band set up actually functions. I have seen close ups of the bigger models but the little guys are so small you can never see detail of that area. Any chance of some close up pics?
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Old Feb 01, 2013, 07:23 PM
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Malaysia, Selangor, Kajang
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Quote:
Originally Posted by Jimmy JFlyer View Post
So I have looked at a lot of "living room flyers" and I am wondering just how the prop/rubber band set up actually functions. I have seen close ups of the bigger models but the little guys are so small you can never see detail of that area. Any chance of some close up pics?
The prop hanger/thrust bearing is usually made from guitar string. Either the No. 1 or No. 2 string.

Mine is a bit unconventional since I have a tendency of trying to solve problems myself rather than ask for advice or look at how others do it. Sometimes my attitude makes life a bit harder. But it's half the fun for me.

The front portion of my thrust bearing is the same as the normal pig tail bearing. But instead of a pig tail, I use a simple U bend for the rear of the bearing. My reasoning was that you almost never want to adjust for up thrust, it's always down thrust. If you find yourself needing upthrust then your plane is too nose heavy in the first place. Down thrust is different. It's needed because the speed the plane flies at launch is significantly greater than the rest of the flight so down thrust is needed to normalize the high lift created by the wings at the beginning of flight.

The other more obvious reason for me using my thrust bearing is that I hadn't heard of the pig tail bearing (due to my stubborn tendency of doing things myself first). Mind you, even if you know about the pig tail thrust bearing, searching for information on it isn't particularly easy. There's this assumption in the free flight community that everyone knows what the pig tail thrust bearing is so plans will simply mention to use a pig tail thrust bearing without explaining how to build one :P

The more normal way of doing it is to use the pig tail thrust bearing. The pig tail holds the rear of the shaft and is what makes it possible to adjust the angle of thrust. The pig tail also makes the prop removable. Just unhook the pig tail form the prop shaft and slide the shaft out the front. Since everything's made of spring steel hooking and unhooking the shaft from the pig tail won't deform the shaft or pig tail.

Here's a video on how to make a pig tail bearing:
Making a wire pigtail thrust bearing (8 min 43 sec)


Of course, you could also buy commercial solutions like this: Aluminium Thrust Bearing
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Old Feb 01, 2013, 11:14 PM
For us He died, in me He lives
Jimmy JFlyer's Avatar
United States, MI, Saint Clair Shores
Joined Dec 2008
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Nice vid and pics, thank you very much.
I see now. Only thing I would still wonder is how the pigtail bearing mounts to the motor stick. It looks like yours (your style)is inside a straw type tube?

So I went and looked up vids on proven little performers like the Poonker Ministick and similar planes and none keep the low ceiling yours does nor did they keep a tight enough turn to actually fly in a "living room" as they state. So far the only one that has done both has been your little guy. I did find one called the "Living Room Stick" that used 3mm rubber and it couldn't stay off the ceiling. They mentione that they wished they had 2.5mm rubber and it might not have been as hard a climber.

The "Portable indoor plane" seems to eb the obvious ticket.
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Old Feb 02, 2013, 02:49 AM
TheyreComingToTakeMeAway!
derk's Avatar
USA, ID, Coeur D'Alene
Joined Dec 2003
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slebetman, thats the same video i saw before i tried to make my pigtail bearing
to mount the bearing to the motor stick, you cut in from the nose towards the tail , then glue it in the cut and keep pressure on the balsa to help it conform around the wire. not sure how much thats needed but it should make it a stronger joint than just gluing.
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Old Feb 02, 2013, 08:40 AM
For us He died, in me He lives
Jimmy JFlyer's Avatar
United States, MI, Saint Clair Shores
Joined Dec 2008
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Thx Derk. So then just slide the upside down "V" up into the cut so that the ends are hanging down right?
Certainly makes sense.
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Old Feb 02, 2013, 12:48 PM
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derk's Avatar
USA, ID, Coeur D'Alene
Joined Dec 2003
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yes, and giving it a little extra room helps keep the motor off the motor stick while it unwinds. mine should probably be a little farther away as it did have a knot hit it recently.
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Old Feb 02, 2013, 04:03 PM
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slebetman's Avatar
Malaysia, Selangor, Kajang
Joined Jun 2009
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Quote:
Originally Posted by Jimmy JFlyer View Post
Nice vid and pics, thank you very much.
I see now. Only thing I would still wonder is how the pigtail bearing mounts to the motor stick. It looks like yours (your style)is inside a straw type tube?
No, it's not mounted to a tube (there is no tube). The bearing has an L bend at the top which is simply skewered and glued into the motor stick and then a small piece of glue soaked tissue is taped over the stem as reinforcement. Sometimes I glue a small piece of scrap balsa instead of tissue to bury the stem in wood.

Quote:
Originally Posted by Jimmy JFlyer View Post
So I went and looked up vids on proven little performers like the Poonker Ministick and similar planes and none keep the low ceiling yours does nor did they keep a tight enough turn to actually fly in a "living room" as they state. So far the only one that has done both has been your little guy. I did find one called the "Living Room Stick" that used 3mm rubber and it couldn't stay off the ceiling. They mention that they wished they had 2.5mm rubber and it might not have been as hard a climber.
The normal circling diameter of my portable plane is actually much larger than my living room. But I can trim it to fly smaller circles by deflecting the rudder (one of the advantages of the design). For my living room, I deflect the rudder by around 20 to 25 degrees. This makes the circle tighter but also causes the plane to spiral into the ground. To compensate I also increase up elevator by around 1mm to 1.5mm (another advantage of the design). Then I wind to around 500 turns (normal flight is around 1600 turns for 040 rubber or 3000 turns of 030 rubber). If it hits the ceiling at 500 turns I reduce the amount of elevator and try again. If not I try 800 turns. Repeat until I'm happy with the flight then pack up and go to bed (because by this time I'd have spent at least an hour flying the little plane).

That's what flying free flight is all about. Trimming it until it flies nice. The great thing about this plane is that it's so consistent. If by trial and error I find 700 turns flies just under the ceiling then I'm fairly confident that next time 700 turns will do roughly the same thing. If it doesn't then at most I'd need to adjust the elevator a bit.

I also fly at the train station in the morning before going to work. I fly in the lobby in front of the turnstiles. It's quiet enough between trains that I can usually get two or three flights per day before I have to board my train. Using the trial and error trimming method it took me a week to find the perfect trim and number of winds to fly well there.
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