RC India

RC Models => Electric Planes => Topic started by: abhay on August 31, 2012, 07:16:15 PM



Title: want to build a balsa glider..
Post by: abhay on August 31, 2012, 07:16:15 PM
Hello dear modellers,
i am a bit fed up of using other materials and scratch building. :banghead:

Now i wanna build a glider made up of balsa.Yes glider, because i am fed up of crashes these days.

I need suggestions for plans.Especially from seniors.I will start building from tomorrow. :)

I want it to be as small as possibe. >:D

I have electrical setup weighing 70gms, providing a thrust of 120 gms.

I guess wingspan will be under 1000 mm.
I will update the name of the thread on the plan i decide to build.


Title: Re: want to build a balsa glider..
Post by: saikat on August 31, 2012, 07:43:00 PM
are you planning all sheet structure or open frame
covered with tissue/film ?

google "Hangar Rat plan" for a model which is almost guaranteed to fly
it is a rubber power about 22" span so you will need to enlarge about
1.5 times and adapt a little for rc




Title: Re: want to build a balsa glider..
Post by: saikat on August 31, 2012, 07:48:43 PM
http://www.aeromodelling.gr/ForumS/index.php?page=153


also check out the above link - this is simple and
surely a good flyer - more importantly it is quite easy to build.

give me details of your power system


Title: Re: want to build a balsa glider..
Post by: abhay on August 31, 2012, 08:21:43 PM
thanks saikat..

planning for frame structure covered with film like monocoat/auracover etc.
Since its a glider, it can even exceed the weight to thrust ratio.

I want it to be tractor, but dont want motor to collide directly on crashes.


regarding electronics:
18-11 2000kv Micro Brushless Outrunner
turnigy 6 A esc
5gm servos(6.5gm exactly) * 3
rhino 360mah
Rx
+accessories like pushrods,props,horns etc
these all count for around 70 gms.
i even wanna carry a payload of turnigy camera 20 gm.

thanks
abhay


Title: Re: want to build a balsa glider..
Post by: buzz_rc on August 31, 2012, 08:30:24 PM
Try building this http://www.gryffinaero.com/models/ffpages/plans/pushe/pushe.html
You will need to modify it for rc use but trust me, I have built and flown it, she is extremely stable in flight and very easy to fly.


Title: Re: want to build a balsa glider..
Post by: abhay on September 02, 2012, 02:44:30 AM
saw many pictures of gliders.
Not following any plans, but decided to build something to have 1000mm wingspan.chord 110mm.Flat bottom airfoil.
Want to have something with polyhedral wing for stablity.
The progress so far:


Title: Re: want to build a balsa glider..
Post by: abhay on September 02, 2012, 02:54:25 AM
more


Title: Re: want to build a balsa glider..
Post by: AEROVISHWA on September 02, 2012, 10:19:32 AM
i see there is no central spar on the wing..... u missed it...or any reason for not putting it...!


Title: Re: want to build a balsa glider..
Post by: abhay on September 02, 2012, 01:19:15 PM
you pointed out the right thing vishvesh..
actually i forgot to do so. :banghead: :banghead: I was building it in a hurry.Later on even i noticed that i missed it. >:( It may sound stupid thing but it is so far my first completely-balsa build wing, so dont have too much experience.
But since it has to take a small weight, say maximum 150 gms, so i dont find any further use for it..
If you find it necessary for this build, just tell me some measure to put it.
one more thing, as i am going to give it a polyhedral, so do i need to add any ailerons? or would it be functional?


Title: Re: want to build a balsa glider..
Post by: VC on September 02, 2012, 01:58:19 PM
Good going Abhay!

You can add the central spar even now. It will add strength to your wing. Cut small notches at the bottom of all the spacers and line up a balsa spar. Contact Saikat for further details.


Title: Re: want to build a balsa glider..
Post by: AEROVISHWA on September 02, 2012, 02:10:14 PM
a spar is very important to the structural strength...  under load there will be a twist in the wing....

using polyhedral will increase stability but will harm  rolling....
alirons will work but very little... rather refer a larger rudder for turning.... but be careful when u give input.. too much rudder and the glider will get into a spin....

for the spar.... cut a 6mm square at the end of the LE sheet and put in a 6mm spar....


Title: Re: want to build a balsa glider..
Post by: abhay on September 02, 2012, 03:32:08 PM
thanks VC sir and vishvesh,
1: for spars, can just a flat rib of balsa say 10mm wide be stuck at bottom joining all spars? I know that cutting notches will be a great deal at this level.
2: regarding rudder, vishvesh, ill go with your idea. Initially i will reduce the expo to say 40%. Later on i will go on with trimming it.

3: A question: do we have to follow the same rule of thrust i.e. 2 degree down and 2 degree right, in gliders as well?


Title: Re: want to build a balsa glider..
Post by: AEROVISHWA on September 02, 2012, 03:45:10 PM
for gliders u need more down thrust...!!! i have seen planes  with 8-10 degrees of down thrust....

my glider ( ZZIP soarer) has around 5-6 degrees of it... still needs 2-3 more....
start by 2... if u feel necessary add more... ( just add washers to the top 2 mounting screws)

also remember thrust and CG interact... make sure ur CG is precise and then check the thrust angle....

and when u have down thrust dont check the thrust holding the plane in hand... rather fly it for testing..


Title: Re: want to build a balsa glider..
Post by: abhay on September 02, 2012, 04:52:06 PM
i have a CF tube 2mm*1mm. can they be used as central spar?
means, i want to stick it to bottom by cutting knotches, will that help?


Title: Re: want to build a balsa glider..
Post by: AEROVISHWA on September 02, 2012, 08:37:40 PM
should work....!!


Title: Re: want to build a balsa glider..
Post by: abhay on September 02, 2012, 10:58:05 PM
hi.. the overall progress yet:

vishvesh, i have reinforced the first dihedral of wing using the CF(unaware about nomenclature). Hunting some CF for reinforcing the edging parts.

The overall weight of setup is 62 gm.

Please suggest some covering material.



Title: Re: want to build a balsa glider..
Post by: abhay on September 02, 2012, 11:01:35 PM
more:
showing dihedral and proportion of wing:fuse.

fuse length is 590mm.


Title: Re: want to build a balsa glider..
Post by: VC on September 02, 2012, 11:24:34 PM
Looking good! Doesn't look scratch built, rather it is good enough to pass off as a model built from an established plan. You've done a very good job here. Congrats! :thumbsup:


Title: Re: want to build a balsa glider..
Post by: saikat on September 03, 2012, 05:43:02 AM
Nic one Abhay - going to fly well.

One comment though - I notice you have
cut lightening holes in the fuselage pod and the
tail.

If you still have the cut out pieces - weigh them
and see how much weight you have saved - my bet is
less than 2 grams - not worth it.



Title: Re: want to build a balsa glider..
Post by: abhay on September 03, 2012, 09:38:34 AM
yes saikat sir.. i just wanted to reduce weight, but these things are not helping..
i think i can further save weight in covering. so need suggesstions.

i have covering sheet from RCD, and other option is common stationary-acralic sheet, which is the other option.
acralic sheet will be lighter no doubt, but is very weak and stands nowhere as compared to conventional covering.

edited.
searching for light and hard wire for pushrods. Bicycle spokes would be too heavier. I read somewhere at Kalyanprodhan sir's post of using heater wire, but cant get the specification.


Title: Re: want to build a balsa glider..
Post by: abhay on September 09, 2012, 12:26:58 AM
more images of completion


Title: Re: want to build a balsa glider..
Post by: abhay on September 09, 2012, 12:37:55 AM
adding electronics..

covering has increased the weight. i am wondering whether my micro motor will take it up or not.. :-\

max thrust of motor(as per specifications) =130 grams.i am considering it to be 120.
i am guessing that the AUW may go upto 180 grams.

what should be the power to weight ratio for this glider  ??? .I have read people going as below as 0.3:1.
Need suggessions. :help:


Title: Re: want to build a balsa glider..
Post by: KALYANPRODHAN on September 09, 2012, 01:22:26 AM
For you, I have just posted my incomplete plane.
Have a look at it here  (http://www.rcindia.org/electric-planes/spadmania-scalling-down-for-electric-2nd-cub/msg114855/#msg114855).

Thanks


Title: Re: want to build a balsa glider..
Post by: abhay on September 09, 2012, 01:36:53 AM
One more thing..
actually wanna thank you kalyan da.. regarding pushrods. :salute: :salute:
actually i read in some post of yours(now i got the post  >:D  ;D ) that heater wires could be used as pushrods.. i didnt used it as complete pushrod, but was very useful in joining the CF rods, to control linkages.Through heater wire,i got options from 1000,1500 and 2000 watts for softer, harder and too-hard wires.
here i have used 2000 watts wire.


Title: Re: want to build a balsa glider..
Post by: abhay on September 09, 2012, 10:41:31 PM
the scratch build chuck glider as well. i may becoe the payload to be dropped from sky, when my glider soars..

it was build as an experiment just to see my workability on balsa..


Title: Re: want to build a balsa glider..
Post by: VC on September 09, 2012, 10:49:52 PM
You may want to increase the area of your V Tail. It looks a tad small. Does she glide well? ???


Title: Re: want to build a balsa glider..
Post by: abhay on September 10, 2012, 02:01:04 AM
yes VC sir, she glides very well and very slowly,at walking speed. even i dont know why..
i was actually inspired by:
http://www.youtube.com/watch?v=lnMftXxGafE
but tail was my choice


Title: Re: want to build a balsa glider..
Post by: abhay on September 19, 2012, 10:30:15 PM
Today was maiden... a great day with Bilal  :hatsoff: :hatsoff: :hatsoff:

I added the electronics in the simplest way.. not emphasizing on the looks. Setting CG was a great problem :banghead:. Battery was added just behind the motor to balance it without adding any dead weight.. it was a success thereafter. :) :)

First we took some glide tests, thanks VC sir for "Jhadi Technique" :bow: :bow:. then we took it on a one storey construction building and chucked it to check the glide..
Glide was nice.

We then tried ROG takeoff, took off and crashed and trimmed model every time. finally it flew like charm.
First pilot was Bilal and then it was me.I flew very well with damaged propellor.

We took videos from mobiles.
Waiting for bilal to edit video. video also has a mystry and a history. >:D the quality may be a bit disappointing :banghead:

the pic shows the progress after the motor was mounted.


Title: Re: want to build a balsa glider..
Post by: AEROVISHWA on September 19, 2012, 10:47:32 PM
saw bilal's pics....  nice work done...!!


Title: Re: want to build a balsa glider..
Post by: satz flying on September 19, 2012, 10:48:51 PM
 :goodjob:


Title: Re: want to build a balsa glider..
Post by: VC on September 19, 2012, 11:23:17 PM
Congrats! Glad that the 'Jhaadi" technique worked.  :giggle: You may want to explain that to the others. Waiting for the video.


Title: Re: want to build a balsa glider..
Post by: abhay on September 20, 2012, 12:00:35 AM
Yes the "jhaadi technique"  :giggle:  :giggle:.. or the "tall grass gliding test" i woud say..

Its just a test to check whether "aall ez well" with your plane before flying..

Jokes apart: I would post the VC sir's exat words.It explains it better.

"learnt a good trick from an experienced flyer:

1. Load your model with ALL electronics.
2. Battery, ESC, Motor, Servo, Receiver, Push rods - EVERYTHING!
3. Calculate and balance the model at CG.
4. Find a field with tall grass.
5. Chuck the model with full weight from shoulder height - flat throw - not at an angle up or down.
6. If the model glides perfectly for a landing into the grass - it will also fly well under power.
7. Now power it up and FLY!

If you see the third diagram on this page, the glide angle should be, ideally, half / three fourth the angle created by the red line to the ground.

http://takebackthesky.com/glossary.php "

My glide angle was different as it was a glider..

Thanks  :thumbsup:


Title: Re: want to build a balsa glider..
Post by: VC on September 20, 2012, 12:13:43 AM
The 'experienced flyer' is Saikat at Dufflaghur T.E. Last year at around this time, I had enjoyed his gracious hospitality.


Title: Re: want to build a balsa glider..
Post by: Bilal on September 20, 2012, 12:16:59 AM
sorry for the delay guys, but since the video was shot in multiple sections on multiple cell phones  :giggle:, it would take me some time to collect all of them......but video would be up by tomorrow afternoon


Title: Re: want to build a balsa glider..
Post by: Bilal on September 20, 2012, 12:38:29 AM
meanwhile, have a look


Title: Re: want to build a balsa glider..
Post by: satz flying on September 20, 2012, 12:51:34 AM
nice plane . . ,


Title: Re: want to build a balsa glider..
Post by: abhay on September 23, 2012, 12:02:31 AM
Hello all.. today was another flying session.
have a look at the video.
Special thanks to bilal for recording video. and background commentry :giggle: :giggle:

i have no idea about video editing softwares. so its unedited.
just keep the volume low before playing
http://www.youtube.com/watch?v=Y-Q2x7e7pp8&feature=youtu.be


Title: Re: want to build a balsa glider..
Post by: AEROVISHWA on September 23, 2012, 10:10:14 AM
nice flying... but next time be sure go a little early.. its was too dark.. chance of loosing ur planes....


i liked " UTARIA MAT... POORI BATTERY CHOOSE LIJEA..."...


Title: Re: want to build a balsa glider..
Post by: Bilal on September 23, 2012, 10:21:20 AM
actually it was windy all day......and by the time the winds died it was already quarter to 6, so we got only about 20min of daylight, thats why the videos are a little dark.........and that was me shouting my lungs out


Title: Re: want to build a balsa glider..
Post by: abhay on September 23, 2012, 02:53:34 PM
It was bilal uttering, "poori battery choos lijiye"..

i  need some free video editing software to upload the first attempt videos.. ROG takeoff was all i wanted. First attempt has was all about ROGs.  


Title: Re: want to build a balsa glider..
Post by: KALYANPRODHAN on September 23, 2012, 08:54:55 PM
I use K-Lite mega codec pack(Free) and TMPG4Exp portable. However TMPG4Exp is not free. But I can help you. However, virtualdub is free.
If you purchase PCI Firewire card of Enter, you will get licensed Ulead video studio on it's CD with key @ < :Rs: 300/-.


Title: Re: want to build a balsa glider..
Post by: rastsaurabh on September 23, 2012, 11:35:29 PM
Nice glider .... well built..... what is the material used for coating ...and where it can be found?

Regds
Saurabh


Title: Re: want to build a balsa glider..
Post by: abhay on September 24, 2012, 12:38:39 AM
the material for covering film is the covering film you get at RCD. Its a bit  :-\ much heavier than monocoat and oracover, but serves the purpose.
I really appretiate RCD for selling these stuffs at "value for money" price..


Title: Re: want to build a balsa glider..
Post by: VC on September 24, 2012, 10:53:06 AM
Very well done. Saw the video and found the model to be beautiful and the background chatter hilarious! Persistence pays.


Title: Re: want to build a balsa glider..
Post by: anwar on September 24, 2012, 11:07:17 AM
need some free video editing software to upload the first attempt videos.. ROG takeoff was all i wanted. First attempt has was all about ROGs. 

Just use what is provided by the world's richest man :giggle:

http://windows.microsoft.com/en-US/windows7/products/features/movie-maker 

There are versions available for earlier versions of Windows.

If you are on a Mac, just use the iMovie software that comes free/included in Mac OS X.