Can you imagine that there was NOT A SINGLE FLIGHT OF 10+ seconds in the last 4-5 years, despite my Rs 1000 prize offer?

Last month, frustrated with lack of results, I increased the prize to Rs 5000.
And it was taken within 24 hours!
By Imperial Fire.
With a paper model!

Boy, did you guys lose a real opportunity!

But don't worry. New opportunities are coming.

Hope to launch the next project on 15th Dec, after this contest ends.
Maybe a new Contest in the New Year?

Quote from: WeekendFlyer on November 29, 2020, 05:10:33 PM
Congratulations to the student who learned so well from the teachers who guided so wisely  

I think similar results will follow.

We will have some good competition amongst us.

Thank you for appreciating my effort . Yes , it was tough for me too . Being a newbie , it was never easy to perfectly trim as Iyer sir did even after he and freeflight told everything behind - physics , practical tips etc etc . I was depressed and worried whether I could make it before the last date . So I thought let you guys win this time . But I kept on trying , reading this forum again and again . Took some time to identify what is wrong with my glider . I knew my glider was not perfect when I sent glide video to Iyer sir . But his reply changed everything . He told me to read the post of decalage again , and that was it! Mine was negative ! That's why whatever I do , be it is perfect CG , elevator tab , rudder etc wont do any good ! And once I changed it to a positive degree , result was obvious ! Perfect test glides! As if the glider wanted to fly on and on (sadly my frontyard was not enough !) And I needed a simple push , not as hard as seen previously ( that Freeflight commented on it) . So guys , do post your videos here or send to Iyer sir or freeflight . They understand what's wrong and will guide you . I had many specators in the field appreciating the smooth glides and one man came to me with a business invitation ! I asked him why and he told he has notbseen it before and wanted to sell it as a kit in his shop I told him that I am not into business and its just a hobby . I am the only person doing this here and so people are surprised and enjoys watching it glide in circles . Most of them wants to know whether I bought it or built by myself . Anyways , it's thouroghly enjoyable and I look forward to your videos too . I know there is tough competition as I saw Hitesh , Nitya and Karthik who did better than me in initial test glides . Very happy that I learned a lot more than just building an RC plane which  is lot more easier since we have the remote with us after launch and timely correctons are possible . Thanks everyone !

Hi everyone,

Just because it's page 12, don't skip the previous page.

There's a lot of good stuff on page 11...

Quote from: K K Iyer on November 29, 2020, 07:14:00 PM
Hi everyone,

Just because it's page 12, don't skip the previous page.

There's a lot of good stuff on page 11...

For example, see this by Glidiator. Never seen an Indian catapult launch video before...

That is truly a great video by Glidiator of launching. Not seen any such clean video launch in the world wide web.

One thing that must come through in the second, third .., contest is that you competitors from that point onwards, try and think of your own solutions. Ask here if you are unsure of your OWN solutions. That is when by teaching yourself to analyze cause and effects, you gain experience to excel. Experiment, see your results. Did that change help or hurt? Are you heading in the right path to get better flights? For example: A roll and then a dive. Should you look for for a rudder offset or elevator? Both? Why? What did you observe? What is the first thing you will modify, knowing to make only one change at a time?

For the first set of competition such as this, it is both OK and correct to ask for guidance. Remember, to experiment by yourself to gain knowledge, what works, what does not and why.

I am looking forward to see your wonderful CLG videos a YEAR FROM NOW, how wonderful you have got.

Mr. Iyer, , in my opinion, the reason you did not get a bite in the first go around, is truly but sad speculation that no one was ever motivated to go through. But this time these kids are wonderful and have the desire to learn and enjoy. That clearly shows.

The MOST important reason for such good flights and participation  this time is the fact that YOU Mr. Iyer made all the superb kits that is giving them a chance to be successful.  Your contribution here is very well noted and worthy. Thank you for doing that. Most kids would give up just sanding the wing aerofoil. But you provided the correct tools for them to be set up for success. Congratulation to you, Mr. Iyer.

Well said FF.
Second your appreciation of KK's efforts to promote interest in Gen next.

As mentioned the greatest teacher is experience. Learning by doing is the best way to reach excellence.
There are no short cuts. If you are an Aeromodeller- the proof of the pudding is your flight performance.

And I always say - " Failure teaches you more than success".
Analysing and finding out what went wrong adds to your expertise.

Here's Weekendflyer's problem

My guess is that he went to the catapult stage without first settling the glide phase.

What do you guys think?

Quote from: K K Iyer on November 29, 2020, 07:02:04 PM
Can you imagine that there was NOT A SINGLE FLIGHT OF 10+ seconds in the last 4-5 years, despite my Rs 1000 prize offer?

Then one day I got a suggestion that I should provide kits and make it a one design contest.

That is what made this Lunchbox build/contest so lively.

The person who made that suggestion is actually a member of this Lunchbox group, but has fastidiously maintained a scrupulous silence.

A big thank you to SANJAYRAI55! 

In case you didn't know, he is the author of the largest number of model build threads in RCINDIA!

I played the Weekend Flyer video in slow motion and full screen. The launch angle, bank angle and the climb is all correct. Almost there, Weekend Flyer. Good height too. Then it appears that the model  tries to go for transition but rolls over hard to the right . Cannot recover, so straight down. Model Needs to climb right and as seen in your video which is Correct, but roll and transition to the left into glide phase. BUT Your glider kept going to the right.

My suggestion would be a) Make sure your wing is installed straight on the fuselage  that is not skewed to the right at all. If it is skewed to the right even a small bit, there is perhaps another option for you only. b) Launch exactly the same way as in your above video making sure you do not have any rudder to the right and just a bit rudder tab  to the left to solve the right roll issue. b)  Once the hard roll issue is solved and then if it still dives straight down, add a bit of up elevator tab on the right side of the elevator only. This is based on the best I can see in the video.

Experiment one change at a time and see.

Looking forward to your next video. Congrats on getting a smooth very good height and right climb based on the buildings on the background.

PS Weekend Flyer: Very good call to have your friend film the flight from behind you. This way we got a good perspective of you launch, transition and glide.

Everyone Else: can you have your friend making your flight video do the same ? Would be nice.

Quote from: K K Iyer on November 30, 2020, 12:20:05 AM

Quote from: K K Iyer on November 29, 2020, 07:02:04 PM
Can you imagine that there was NOT A SINGLE FLIGHT OF 10+ seconds in the last 4-5 years, despite my Rs 1000 prize offer?

Then one day I got a suggestion that I should provide kits and make it a one design contest.

That is what made this Lunchbox build/contest so lively.

The person who made that suggestion is actually a member of this Lunchbox group, but has fastidiously maintained a scrupulous silence.

A big thank you to SANJAYRAI55! 

In case you didn't know, he is the author of the largest number of model build threads in RCINDIA!

Iyer sir, sorry for the silence. Someone in the family is very ill, and I have been quite tied up. I hope to actively participate soon

Quote from: K K Iyer on November 29, 2020, 11:53:09 PM
What do you guys think?

@Weekendflier ,my suggestion would be to  read this post before attempting catapult . Only after I was satisfied with the test flight ( it took 3 weeks!) I went for CLG.

Quote from: K K Iyer on November 20, 2020, 09:48:05 PM
Let's get back to basics for a moment, and go step by step.

Step 1. Build everything straight. No rudder offset, no stab tilt, no wash in, no wedge, no trim tab.

Step 2. The designer has specified the CG position after trials. Let us balance our model at the specified CG first.

Step 3. Try to get a straight glide slope from say 5 feet high to a point about 30 ft away on the ground.
This approximates the glide slope of the model

Step 4. Launch your test glide a bit nose down, pointing at a point on the ground about 30 ft away.

Step 5. How fast to throw? A bit slower than you'd throw a marble at the same target.

Got a straight flight of 3-4 seconds, neither climbing nor diving, neither turning left nor right?

If it turns a bit left or right, let it be for the present.

If it dives, add an up elevator trim tab. This is a half cm piece of the supplied triangular wedge, or a a similar piece of matchstick.

If it climbs, add a tiny bit of plasticine to the nose and try again.

THE OBJECTIVE IS TO GET A STRAIGHT GLIDE FROM A 5-6 FOOT LAUNCH TO A POINT ABOUT 30 FEET AWAY ON THE GROUND.

Step 6. Now we want it to turn left on glide.
So we twist in a little left rudder.
And it glides nicely in a slow left turn in the glide.
But when catapulted at high speed, it makes it spiral dive to the left...

Perhaps this left rudder is not such a good idea...

Maybe worth looking at reply #204

Go step by step . You can't go forward without clearing the previous step . That is how I proceeded . Regards.

On catapult launch, model goes straight up.
And then goes straight down.

This is a well known typical problem.

What this flight pattern means is that the decalage is not enough!

The correct solution is to remove the stab, and sand the place where it is mounted, to give about 0.5-1deg negative incidence, ie, stab leading edge lower than it's trailing edge.

Since this is difficult to measure, aim for a 0.1" slope at the bottom of a 10" long fuselage.

What to do if the stab is already stuck on with Feviquik and can't be removed?

Somehow we have to add a little UP elevator effect.

For this you have to make a wedge. About 10mm long, 5mm wide, 1mm high at the back, sharp at the front. (As provided in kit #5 onwards)
And stick it above the trailing edge of the stabiliser. You may need more or less length.

Since I'm not a catapult glider expert, I went by the advice of Freeflight, who prefers zero zero setting.
In other words, the wing and stab parallel to each other. Or NIL decalage. This gives a very high straight up launch

This is how the first 11 kits were set up. So all of them dive despite correct CG, and need some UP elevator.

Kits #12 onwards have about 0.5deg decalage built into the fuselage.

So they will probably glide nicely, but may loop under power.

But curing a loop under power is easier than curing a death dive from the top of a high launch  

Will tackle looping at full power in a subsequent post.

And the difference between a wedge and 1x1mm matchstick if anyone is curious enough!

Don't know if this is the correct way to do it ; but this is what I did . Inserted a thin piece (sanded to less than 1mm) of match stick under the LE of wing .

Quote from: SI74 on November 30, 2020, 09:26:10 PM
Don't know if this is the correct way to do it ; but this is what I did . Inserted a thin piece (sanded to less than 1mm) of match stick under the LE of wing .

Yes. Correct.
Same as lowering the leading edge of the stab.

 Just re clarifying:

In a Catapult flight we have three different but all vital phases of flight. The launch (2 seconds) , the transition (fraction of a second) and lastly the glide where most of the time is spent( goal here is 2 minutes glide with help of thermals).

So you want to get as high as possible so you can glide for a long time. Hence the Zero-Zero built-in decalage. All CLG's need a bit of (mind you , very small) decalage so you do not go up and straight down, you transition to the left and glide to the left.

When I said to use a matchstick, I assumed most of you do not have access to 1/32 or 1/64 balsa. You need to sand it down or split it with a sharp blade. I call this a tab. See my first Lunchbox video, very second pull had nearly 27 second flight, second flight based on these principles. In that Lunchbox I used a matchstick as I wanted to prove it to myself before recommending. These were all trimming flights, flight 1 , 2 and 3 . All using a an intentionally build heavy (7 gram ) glider with office rubber bands.

So go for the maximum height to increase the glide time. Once I trimmed, to fly slower, I lost the Lunchbox. We chased it for one and half mile but kept rising and went over the woods after which we did not see it.

There are many roads that leads to Rome. Eventually, the goal of a HLG or CLG  is to get a floaty glide and the stop watch is your judge. If you build in any decalage, other than zero, you will not climb as high.

My goal was to share my experiences so that you guys come as close to a 40 second flight in your first glider, perhaps loose it. In my opinion that might entice you to join the wild and beautiful world of CLG, cost effective, not special model airports, but you have to put time into it.

"Perhaps lose it " @Freeflight , that's my worst dream And so I have asked Iyer sir for two more kits But surely will try your suggestions on my next glides - sand up tabs , less decalage etc are in my lists (experiments) . I found matchsticks a better idea than balsa for perfect adjustments (from your valuable suggestions) since it's strong enough , easily sanded and lightweight .

Decalage depends on where you apply the glue first - at the LE or TE of the wing (midline) - right?

I think there's a fundamental difference between how we historically learnt to fly HLG/CLG in India, and how CLGs are typically flown in the US.

In India, (lacking good rubber) we started with HLGs, launched not javelin style, but with a straight arm bowling throw (no elbow bend).
Released 45deg nose up, 45deg right bank.
Resulting in a right spiral climb and left circle glide.
This required some decalage and some left rudder.
This technique probably got carried over to CLGs.

I used to be amazed at CLG videos from the US, showing nearly vertical launches, going almost out of sight straight up. Then a little flop for transition, and off she goes on a floating glide.
Never saw such steep, straight launches, only spiral climbs.
Glidiator's recent launch slo-mo was an eye opener!

So when I insist on decalage, I guess I'm historically compelled, ie, old fashioned 

Quote from: SI74 on November 30, 2020, 10:05:02 PM
Decalage depends on where you apply the glue first - at the LE or TE of the wing (midline) - right?

No.

Mr. Iyer, I too had started the same way in HLG and CLG too. What changed for me was the Tich article with full size plan by the designer in the Indian Modeler magazine.  Next it was the original Yellowbird 13, where I got introduced to stab tilt, washin on the inner wing, adjusting decalage by -1/64 on the stab, wing at zero, left rudder tab, right launch and left glide etc. Had also built Arora Canberra that one day it took off from Breach Candy , Mumbai with friends in a low 30 foot high thermal. We ran after it for about a one km to the Mahalaxmi temple area (just 14 or 15 years old). Lost it in the high buildings. So got introduced to Thermals and Out of Sight flights. 45 years later rebuilt the Canberra and Tich CLG's, posted on RCI . Has been an enjoyable journey.

http://www.rcindia.org/kites-trains-free-flight-and-all-others/tich-the-article-in-indian-modeler-magazine/

http://www.rcindia.org/kites-trains-free-flight-and-all-others/the-flight-of-the-canberra/

videos are on YouTube, so play it in full screen and lowest speed in the setting. Straight up, flop to the left and glide. These are only trimming flights not competitive flying. No one has time for videos in competition, only for trimming flight so you can go home and study it.

Contestants: See the videos there. Hopefully a video paints a thousand words. This is what the Lunchbox also does. Unfortunately offered mine to Hung, the thermal God before any  videos.

Back to the topic.

So the trick is to gain as much height as possible, to get maximum glide time. Assuming you have a well built and trimmed glider (most of you are very close based on your reports and videos) what else can you do? As mentioned before , I take serval rubber band launch sticks with me as rubber gets tired and we think the trim changed.
Next ,  to stay within the competition rules,  many of us build a rubber band launch stick with two sets of parallel  rubbers as in photo below. This seems to take the glider even higher, at least for me. Give it a try after you are happy with the flight. Then get ready for sweet but sad flight that like a bird just flies away. A flight you will both enjoy and cherish.

PS : notice that I keep clay on my stick, just in case I need to add to the nose or right or left wing tip based on the weather that day. Too windy, and I still want to fly, add nose clay , move your CG just a bit forward.

For this Contest You can Only USE Office Type Rubber bands , like my Lunchbox videos.

Always PULL the RUBBER BAND to the maximum. If you pull a little, then little more, you have to retrim each time. So pull to the MAXIMUM right from the START.

OK here is my prize for the contestants.

For the first person who gets 40 seconds plus flight, three flights in a row , on the same day, and you show it all in a video. l will mail you an unopened packet of the original  1/16 FAI Tan rubber (16 feet long) that I have saved for years. Since you guys are enjoying this contest, I am happy to present this prize to you. I have two such packets, one for me, the other is the prize for you.

Will include a good kit, firm light balsa CLG too. Should be able to mail it in an envelope with no custom duty on your part, I hope.

Go for it, I know you can do it. You are very close, bravo for your experience on a first model.

Let me reclarify regarding match sticks and test glides.

Match sticks tabs: These are very small. I always attach it with glue stick so I can remove it at the field or sand it down if needed.  Glue stick has enough power to stick to the glider

A) For Rudder tab : See reply #73 and 74. Very small and close to the rudder, dimensions are given based on my glider. Yours maybe smaller or bigger, every glider is different. But you get the point
B) Elevator Tab : See Reply # 151 again very close to the fuselage. Again very thin and small. Use your nail file if too big.
If the model dives put a tab on the Right Side of the upper elevator.
If the model loops put a tab on the LOWER side of Left elevator.
c) Washin Tab : See Reply# 86 and dimensions are given as the first guess. This is the biggest tab. If your tab is too long, then the glider will launch, transition and keep going straight, no turns. Keep cutting the washin tab little by little until it glides turns gentlyto the  left without the left wing dropping in a circles. you are looking for 40 to 50 foot circles.

Glide test:

Glide test should prove that the the model is safe enough to catapult. It does not dive and has a gentle turn to the left.

You should throw it, very slightly pointed down and wings level at the speed at which the model will glide, not a  gentle push as your model will never see such low glides in its CLG flight.  This IS VERY DIFFICULT and needs a lot of Experience. But needed. Practice !

The model should glide smooth, raise its nose up ( shows you have incidence enough that it will not dive back to earth) and a gentle turn to the left. Not too sharp turn to the left. See Photo in Reply# 100.

See the videos as the experts explain in  Reply # 117 first and then Reply # 111. These are 15 minute videos wonderfully made. Study it before you go out next time. It is time well spent

This is how we go almost straight up , flop and glide to the left.