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Author Topic: Mini Stick, indoor room size recommendation  (Read 2903 times)
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herreraa
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« on: October 23, 2017, 09:28:50 AM »

Hi All,
I am new on this hobby. I tried to build my first miny stik , "thefly" during the weekend and it was a total disaster. Did not fly , it look more than a helicopter pointing upward than a plane. Finally crashed agains the kitchen and broke the motor shaft. weight 4.5gr.

I was under the impression that i was doing everything by the instruction but i never fly. It is very frustrating.

Can anybody advice a easy to build mini stick that can fly in a living room ( 20ft x20ft) in circles, with some detailed instruction to follow (if this is possible)?
Many thanks
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Rossclements
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F1D is pretty neat



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« Reply #1 on: October 23, 2017, 09:51:33 AM »

start with this, http://www.hippocketaeronautics.com/hpa_forum/index.php?topic=3614.0. Don't start with this airplane but it is a good guide to start with. do you have any pictures of your model? 4.5 grams seems very heavy.

Ross
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Art356A
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« Reply #2 on: October 23, 2017, 04:31:27 PM »

That was my first shot at a serious indoor model. At first not a good flyer, but that was all due to my inexperience as a pilot. An hour or two spent with a more professional indoor guy smoothed things out.

https://www.youtube.com/watch?v=yeOpfduyqlg

The room is 18 ft. square, 12 ft. high (usable height above the piano 8.5 ft.), and the octagonal tray is about 12 ft. across and a foot deep.

My first try was hopelessly heavy, but the second one came in at about 1.5 x Alan's specs.

art.
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My arms are so weak, it's like that pushup I did last year was a total waste.
herreraa
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« Reply #3 on: October 24, 2017, 11:14:51 AM »

start with this, http://www.hippocketaeronautics.com/hpa_forum/index.php?topic=3614.0. Don't start with this airplane but it is a good guide to start with. do you have any pictures of your model? 4.5 grams seems very heavy.

Ross

I was able to make it fly by cutting 3/32 rubber in half and properly sizing motor stick and tale stick that were too big. But just 4.25grams. The problem is that it was still very tale heavy and i have to add 70gm weigh on front to at least make it work. It only glides but does not climb up.
Here a video of the best flight and some pictures of the model ( broken on the table) and repaired with weight on nose.

https://youtu.be/J7x-srSlKXA


I think the problem now is my construction skill i just use lots of CA glue , it should be a more efficient way to glue this small models.

any advice on glue fast cure...?

Thanks
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Re: Mini Stick, indoor room size recommendation
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jakepF1D
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« Reply #4 on: October 24, 2017, 11:44:32 AM »

Many of us use Duco cement thinned about 50% with acetone.  Generally speaking this is a much lighter glue than CA because most of it evaporates out of the joint when it dries.  That said, I think a much quicker way to drop weight is to use thinner, lighter balsa for the wing and stab.  What type of material are you using for covering?  See if you can find a lightweight plastic bag, or you could purchase some lightweight mylar.

Also in the video, the model still looks tail heavy.  You'll never be able to make it fly correctly if it's tail heavy.  If it's possible, try moving the wing back, and then add more turns to the rubber.
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Skymon
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fly it



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« Reply #5 on: October 24, 2017, 06:00:52 PM »

Balsa cement, thinned 50/50 with acetone. Apply with small paint brush. It's not instant but it's strong and light. Plus you can dissolve it with pure acetone to reposition.
I'd suggest building a new plane to the same plan and see where you can save weight. Thin the spars, ribs and uprights. Leave the motor stick for now.
When I started (not long ago) I built a ministick and then three more, chasing weight reduction each time. You'll be surprised how thin the wood will go.
Your prop is also heavier than an all balsa one.
Keep building, keep learning, keep flying ;-)
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herreraa
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« Reply #6 on: October 25, 2017, 10:43:32 AM »

Many of us use Duco cement thinned about 50% with acetone.  Generally speaking this is a much lighter glue than CA because most of it evaporates out of the joint when it dries.  That said, I think a much quicker way to drop weight is to use thinner, lighter balsa for the wing and stab.  What type of material are you using for covering?  See if you can find a lightweight plastic bag, or you could purchase some lightweight mylar.

Also in the video, the model still looks tail heavy.  You'll never be able to make it fly correctly if it's tail heavy.  If it's possible, try moving the wing back, and then add more turns to the rubber.

Thanks for your comments. I will try to experiment Duco cement. I purchased the paper from a hobby shop but i think it is regular gift paper , it is think but it is not mylar, i will try to get some mylar, any advice about thickness, i am beginner and i do not want to use a mylar that is use for competition and very difficult to install.

I moved already the wing as back as i can, the second picture ( standing model) is the latest position as far back in the motor stick.

QUESTION: How important is the angle of attack , i think i have accidentally glued the standing pole of the leading wing about 1.5 milliliters lower than in the plans. I think that may reduce the angle of attack and consequently the climbing capabilities. any comments.

Thanks 
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Art356A
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« Reply #7 on: October 25, 2017, 02:37:36 PM »

The Minislick plan shows the balance point at the trailing edge of the wing, the wing incidence at 1/16" positive and the tail incidence at zero. Try for those on your model and you'll have a head start.

art.
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lincoln
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« Reply #8 on: October 26, 2017, 03:25:15 AM »

Any properly trimmed mini stick that's near the right weight should fly in a 20 X 20 foot room, though if it's a good one or there is some ventilation it will drift into the wall before it's done. It won't break when it hits something, though.   However, 4.5 grams is about 10 times heavier than the required minimum. That means it needs to fly more than 3 times as fast, requiring much more room for a turn. I'm a bit mystified as to how you got to that weight if you used balsa. I expect that the wrapping tissue you used weighs somewhere between 20 and 40 grams per square meter. That's really heavy by indoor airplane standards, but it would only come to about 0.3 to 0.7 grams. A good mini-stick weighs close to 0.43 grams, BTW. Good Japanese tissue, such as Esaki, ought to weigh around 10 or 12 grams per square meter. You can find vegetable bags  which actually weigh considerably less. I'm talking about the very thin bags you tear off on rolls to hold your broccoli. The only drawback is that you need some really tenacious glue to hold the stuff down. Some kind of contact cement, probably, which you'd need to use sparingly. The vegetable bags are overkill for this application, but light enough. I covered a 26 inch RC indoor model with the stuff, and occasionally flew outdoors.

Probably the plastic bits shown on the plan mean that the Fly can't get down to the desirable weight, but it shouldn't weigh 4.5 grams. If I'm not mistaken, you'll need more than 9X (!) the turning radius for a given bank angle. On the other hand, a light mini stick doesn't have to bank much at all, so it may be possible. You could try fling outside on calm days until you get it trimmed.

Angle of attack is definitely important. You want to be flying fairly slowly, not much faster than stall speed.

Chances are, your current model will fly much better if you make a smaller propeller for it. You could try 5 inches or so, but you'll probably need some fairly thin rubber for it. Even with a larger prop, a Mini Stick that's close to the minimum weight will require a very skinny motor.

It's not about mini sticks, but you can probably learn a lot from Bob Meuser's article about his No Non Cents Pennyplane.
https://www.rcgroups.com/forums/showthread.php?978436-Indoor-Duration/page5 link is in post 62

Also, Ron Williams'  book Building and Flying Indoor Model Airplanes may be very useful to you if you can find it. I think these days it may be found on Amazon.

I think, if you make another model, you may find the most success in that room with a model intermediate in size between a mini stick and a pennyplane, though if you have a larger venue available, I highly recommend building a pennyplane. A good intermediate sized model which I think  would fly in your room might be a Starved Pussycat, especially if kept light. Peck Polymers sells a kit for it. I assume that it flys well, because Dick Baxter's regular Pussycat flies really well, and I assume the Starved Pussycat is lighter. If landing gear is shown, don't bother with it. It would probably fly even better if you shaved down the prop or made one. If the prop assembly includes a plastic bearing that slips on the end of the motor stick, that will be heavy too, and performance could be enhanced by replacing it.  You can make your own bearing, or you can use one of Ray Harlan's. ( http://www.indoorspecialties.com/index1.html ) Ray's bearing forces you to use an appropriately thin prop shaft, and that shaft forces you to make your own prop or some kind of bushing to adapt to props with larger holes. (Try bare guitar strings of the appropriate size.) BTW, Ray sells Ultrafilm, which would be appropriate for mini sticks. Recommend you use something easier for your next model.  But if the model flies in your room ok, maybe it's premature to suggest these refinements. 

This was fun, but I really should sign off. I hope there aren't too many embarrassing mistakes in here.
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herreraa
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« Reply #9 on: October 26, 2017, 09:18:29 AM »

linconn,

Many thanks for the replay it is very useful and encouraging. I am definitely planning to build a new The Fly. In the mean time I had an Peck ROG waiting and this was the best opportunity to build it  my first one and practice building skils.
Here video: https://youtu.be/66QRIW2N2lY. I used a 2 degree angle at rudder to make turn in circles i think it work wood.

I will try to build the pennyplane when i have a place to flight it seems that i need more room that my house.
Thanks again.

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herreraa
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« Reply #10 on: October 26, 2017, 09:21:17 AM »

linconn,
forgot to ask , how did you get into the forum about pennyplane construction i was no able to find it in the list of discussion forum in the indoor flight section.
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Art356A
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« Reply #11 on: October 26, 2017, 11:17:41 AM »

Can anybody here access the Ben Saks video on the Ministick build? I had it in my bookmarks but lost it in a computer crash. He uses CA, but shows how to use it sparingly. This video is just what Herreraa is looking for.

a.
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herreraa
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« Reply #12 on: October 26, 2017, 11:37:19 AM »

is it this one?
https://youtu.be/uNJy3AR7uzE
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Art356A
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« Reply #13 on: October 26, 2017, 02:03:07 PM »

That's it. I think it was intended as a guide to build a kit he was selling but the techniques are just a valid for any indoor starter model.

a.
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My arms are so weak, it's like that pushup I did last year was a total waste.
herreraa
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« Reply #14 on: October 26, 2017, 02:19:53 PM »

I can learn a lot with it .

Do you know what time of paper is been used in this video?
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Art356A
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« Reply #15 on: October 26, 2017, 03:20:20 PM »

It looks like condenser paper. Figure out how much you need, contact me off line and I'll send you 4 or 5 times that much so you'll have enough for your next few projects.

a.
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jakepF1D
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« Reply #16 on: October 26, 2017, 04:27:04 PM »

I would strongly discourage the use of CA in any indoor model if you have any interest in progressing beyond a living room model.  It's very difficult to keep weights down, and more importantly it's extremely difficult to loosen joints when you eventually need to make a repair (and you will need to make repairs). 

I think it's best to start with something like Duco rather than trying to transition after you've already spent a bunch of time trying to make CA work.  I'm not saying CA doesn't have it's place, but it should only be used in certain circumstances.
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Art356A
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« Reply #17 on: November 01, 2017, 06:31:05 PM »

I just pulled up the Poonker plan, and a couple of areas of uncertainty appeared. There's a note at the tail LE that says "2º up". It really means the TE should be up, right? Like 2º up elevator? And it calls for 1/16 wash on the left wingtip. Doesn't say wash-in or wash-out (I'm thinking -in). Help me out, Jake.

art.
 
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« Reply #18 on: November 02, 2017, 09:21:20 AM »

Alex, welcome to the world of indoor free flight.  From the videos you posted, looks like you are having fun and from your questions, it appears you want to improve.

I second what Jake has said about CA glue.  Though if you must use it, a decent way to keep the weights reasonable is to pour yourself a small puddle of the CA glue, dip the tip of a needle or pin into the puddle, and then touch that to the joint.  It isn't as light as a thinned Duco joint, but it will work to get you started. 

Also, I have observed that many beginners are afraid to work with smaller sizes of wood, thinking they are not strong enough.  If you are working from a plan of a known performing model, like Poonker or Minislick, or similar, the wood sizes listed on the plans are adequate.  If you are worried about strength, or worried about breaking things during handling, increase the wood sizes a little if you must, but I wouldn't go more than 10-15 thousandths over the spec's dimensions.

I would also encourage you to try a limited penny plane.  They take about the same amount of time to build as a ministick, but its easier to get them to fly well.  Ministicks are so small that they require a great level of precision to fly well.

Here is the link to the penny plane forum http://www.hippocketaeronautics.com/hpa_forum/index.php?board=24.0

Also worth looking at, if you like lightweight models is the famous Hobby Shopper EZB, by Larry Coslick.  https://indoornewsandviews.files.wordpress.com/2012/10/inav-107.pdf  Build a model faithfully to Larry's listed weights, dimensions, and tests, and you will have an excellent performer.  If you go that route, document the build, and post a some pictures of the finished model.  If you are having trouble sourcing the ~.032" rubber that Larry recommends for the hobby shopper, PM me and I will send you some suitable EZB rubber to get you started.

Good luck, and have fun.
Chris
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herreraa
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« Reply #19 on: November 02, 2017, 10:41:32 AM »

Chris,
Thanks for your email and welcome words.You are on the point , as it was my first plane i used CA all over around every joints so ( in my beginners head)  it will not break.
I already build another and F200 (https://www.youtube.com/watch?v=TtLEY3Rzv1k )that uses foam. I got the weight correct this time but it does not turn or hold elevation. I have ordered 1/16 (0.062) rubber , but for more than 100 turn it seems that is too much torque. Also got DUCCO glue arrived yesterday in the mail. Does it need to be dilutes 50% with acetone or it can be used directly from the tube? 

I will follow your advice on the plane and i will get it documented.

Thanks Again,

Alex
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jakepF1D
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« Reply #20 on: November 02, 2017, 12:26:38 PM »

I just pulled up the Poonker plan, and a couple of areas of uncertainty appeared. There's a note at the tail LE that says "2º up". It really means the TE should be up, right? Like 2º up elevator? And it calls for 1/16 wash on the left wingtip. Doesn't say wash-in or wash-out (I'm thinking -in). Help me out, Jake.

art.
 

The left wing on pretty much any indoor model should have wash-in.  On some models you might have a flat wing or even a small amount of wash-out at rest, but when wound you always want wash-in.

I never pay attention to stab incidence on plans.  Set the stab at zero and do a low power test flight.  Add negative stab incidence until the model maintains a slightly nose up attitude during cruise and descent.  If the model stalls at launch torque, then adjust the thrust line. 
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« Reply #21 on: November 02, 2017, 12:31:19 PM »

Alex,

Duco can be used straight from the tube, but for indoor it is lighter if diluted 50/50 (or more).  You would be amazed at how little glue is actually required to hold an indoor model together.

For your ministick type models, the 1/16" rubber is too thick.  Romash's record flight with "Poonker" used something like .014" rubber, tied into a loop.  If the 1/16" rubber is all you have, try a single strand of rubber, with an O ring tied to each end.  That will keep the torque down a bit, and let you pack in some more turns.  

Speaking of, do you have a winder?  If you are hand winding, you will observe that the motor torques up very quickly.  If you have a winder, you can stretch wind the motor to get more turns into the rubber, while keeping the torque manageable.  

Also, you mentioned your model not climbing or turning...with 1/16" rubber, it should be climbing very fast, and turning very fast.  Check the center of gravity on your models.  I looked at the video of the F200 you linked, and the model in that video is slightly tail heavy, as indicated by the porpoising during the flight.  If your CoG is too far aft, the model will not fly well.  It will have trouble climbing, and will be unstable.  With the CoG too far forward, the model will be very stable, and most likely climb, but duration will be reduced.  The trick is get the CoG and incidence set so that the model flies just below stall, in order to maximize duration.


Hope that helps.
Chris

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herreraa
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« Reply #22 on: November 02, 2017, 01:52:38 PM »

Chris,

Yes i got a 1:10 winder. The only think i am missing is the torque meter. I have research some DIY instructions but i have not decided what would be the best option. I do want to have something that measures actual torque units and not just percentage so it may need to get calibrated. I would appreciate any advice in terms of what range to torque are used in indoor models so i can try to see size i need and any DIY instructions to build one.

Using a single strand is a good idea , i never thought about it. You mentioned " If your CoG is too far aft, the model will not fly well" sorry my beginner question but what is "aft". I sow how important the incidence angle is , last night that i was trying to trim it. If angle was to log it when down, and if it was too high i will stall . And could not me it work with few or many turns , i gave up at midnight after adding weight at nose as desperate measure, it did not worked out....yet.

I hope single strand will help.

Many thanks,

Alex
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cglynn
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« Reply #23 on: November 03, 2017, 10:22:27 AM »

For a torque meter that reads actual torque units, the new style digital meters are the way to go.  Both Mike Kirda and Jake Palmer on here offer such meters.  There are also instructions on this site to build your own digital meter, if you like building stuff.

For trimming, "aft" means towards the back of the model.

While trimming a model, remember to change only one thing at a time.

My personal trimming method involves using a motor that I am pretty sure will fly the model.  Usually about 1.2 times the length of the motor stick (so its not going to be a motor for maximum duration, but a motor that will let me observe all phases of flight...climb, cruise, and decent) and close to thickness listed on the plan.  I will fly all of my flights with 1000 turns, so that becomes a constant.  Then I will change incidence, and only incidence, each flight until the model flies a maximum time.  The next series of flights, if I feel I need to, I will change the center of gravity, and only the center of gravity, until I get a maximum time.  If I had to move the CoG a significant amount, I may retest for incidence in another series of flights.  Once I am happy with the incidence and CoG, I will then start adjusting the motor length, and size to start approaching maximum performance for the model.

The real key, and what many potential indoor flyers do not do (myself included in my earlier days) is to record EVERYTHING about each flight, and only change ONE THING on subsequent flights.  The more data you have, the quicker you have, the quicker you can optimize a model.

For every flight I make, both trim flights and competition flights, I record: Model type and weight, Prop pitch and diameter (if I have multiple props, or my prop has ground adjustable pitch), Motor length and weight, turns put in to the motor, turns backed off of the motor, launch torque, flight time, motor turns remaining, and prop RPM (launch turns - turns remaining / flight time in minutes). 

By comparing the data from each flight, and only changing one thing on the model, you can have a good idea of what is causing a change in flight times, and know if you are working towards improving performance.

One other thing that I really need to mention is that for these small planes, weight is huge factor with respect to performance.  They need to be really light in order to fly well.  If you are much over the plan weight, it will be increasingly difficult to make the model fly well.

Finally, to give you some data to work with...Locally, we used to fly an event called "Ikara Jr." It is similar to "The Fly" that you are working with.  Model weight was around 3g with the 6" Ikara prop.  I flew that event using a 12" loop of 1/16" rubber, wound to 2000 turns at launch.  The model would quickly climb to 24 feet, cruise for 45 seconds or so, and land around 2 mins. 

Hope that helps
CG
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herreraa
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« Reply #24 on: November 03, 2017, 10:38:01 AM »

Chris,
Many thanks for the extensive explanation and tips.
Funny you mention propellers , i broke my third ikara 6in propeller during trimming , i am trying to fix ti with UHU por but is getting expensive. I guess i need to start learning to build my own propellers so i can practice, learn and break as many as i want. Any tutorial you recommend to build simple propellers many foam , or balsa .
Thanks
Alex
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