2nd Chuck - Lunchbox

Started by K K Iyer, October 08, 2020, 08:54:06 PM

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K K Iyer

Quote from: WeekendFlyer on November 26, 2020, 10:35:12 PM
I had proposed an extension before, however, that post got lost somewhere, no issues.
An extension will be appreciated for better competition.
14/12 is fine with me.

Saw it only today.
Missed earlier probably as I had taken a break from this thread...

Glidiator

Early Bird Incentive

A Tiny Tot kit for those who post at least one performance video by 30th Nov 9pm?

So get into action.




K K Iyer


Free Flight

Nitya: nice glide test. I am thinking the video is from a few days back? By now you have probably put a rudder tab on the left side to make it glide the same way but to the left. Also I do not see a rubber hook in the video at the front of the fuselage. I guess you are planning to hand launch. That is very good. Same principles apply.

Tiny Tot: come on guys, this is as the golfers say this is a "Give Me" . Very nice of Glidiator to offer it and also the other model for prize. Tiny Tot is a great model too. Satisfy the condition layed out and collect yours.

Am glad that an extension was approved. Very much looking forward to your photos and videos.

For all those preparing for exams, wish you the best.

K K Iyer

All of you Lunchbox builders,

A few of you sent me videos on Whatsapp, some of which I posted here via YouTube.

During this coming weekend, if any of you manage to take videos and share with me on Whatsapp, I'll be happy to post them here via YouTube.

Even if you don't have any videos yet, I request you to post at least a photo of yourself with your model

This Lunchbox group is somewhat like a family now, and it would be nice to see the face and model of the members. (So far we don't even know each other's name!)

Just a thought. OK?
I realise that some may not like to share their own photos, but there should not be any problem in sharing photos of their model.

NOTE: Videos of competitive flights you have to post by yourself on the contest thread.

Glidiator

Finally got some flight videos. After being used to the very slow flight speeds of indoor rubber power where video recording is easy - taking good videos of a small fast CLG was a challenge.
Some observations in trying to get a decent video from launch to touchdown
1) Very difficult to follow the model at launch to the point of transition as launch speed is very high and model is quite small and following it is tough - rather impossible
2) So after getting launch on record  slowly pan mobile towards model by which time it would have reached the apex of launch and commenced glide
3) Pick up the model with naked eye keeping the centre of the top edge of the mobile just below the model - following model with naked eye - not on mobile screen where it may not even be visible properly..
4) Once you have picked up the model in glide and are able to follow it - can tap zoom to 2x to get better view of model
One will need a very wide angle camera with high zoom to actually keep the model in frame from launch to transition point.

The flights I managed to record decently were in the 30+ sec duration - as I mentioned after recording launch it takes a few secs to get the model back in sight and properly in frame.

In Flight 1 - had an interesting situation as a swallow got curious and flew around the model inspecting it.

In Flight 2 the model did not take left circle and went rather straight. My analysis is that since at that time the wind had died down completely- the stab tilt that was effective when wind was blowing/ gusting was not having enough turning effect in zero wind. So trimming  for different wind conditions will vary. Or the stab tilt that was given by twisting the tail boom had slowly gone back to being straight over multiple launches -  so no turn effect was created.

In slow motion launch video I am using right hand to hold catapult( as a left handed person would do) but banked model to right as for right handed launch as trimming is for right handed launch. This was because I realised I couldn't straighten my left hand completely holding catapult due to a frozen shoulder I'm recovering from.

Lots to learn from a "Simple Model".

Flight 1



Flight 2



Launch in slow motion - mobile automatically stops after recording after few secs

http://www.youtube.com/shorts/LJfgPkrrxIM



K K Iyer

@Glidiator sir,

Wonderful stuff.

I'm glad you're only an 'honorary' participant.

But what an inspiration to the others!

Regards

Edit:
That slo-mo of the left handed launch was great!

Free Flight

Congratulation Glidiator sir, Both flights approaching the 40 second mark ( not an eternity for sure) in still air. Terrific. Very good slow motion launch video. Really helps with someone filming it.

Probably the fuse twist must have gone back to original so the glider went straight. However I have found that a bigger than needed washin wedge produces the same effect. Hence all my tabs are put on the glider with a glue stick, so it is easy to remove or adjust.

Very nice seeing your flights. Enjoy.

K K Iyer

#258
Hitesh Kher has damaged his model by repeated crashes!

I offered to send him spare balsa, or a new kit, or a ready to fly model. For free, of course.

After some hesitation he opted for a kit.

If anyone else needs a replacement, please let me know. Quickly, latest tomorrow night.
So I can prepare on Sunday and despatch on Monday.

Free, but any contribution towards cost, effort, postage is welcome!

Regards

hiteshkher


Free Flight

#260
Glidiator : Your photo on the previous page clearly shows a elevator tab and the washin wedge tab. Also looking close on the first photo, you have installed the rudder with a slant ( LE of rudder more to right of the Center line of the fuse). If that is so, terrific. That is the coolest way to do it. I do the same. This way it may not require the rudder tab to the left.  So do you have a rudder tab on the left?

All other contestant: Follow the simple build process and you too will get a near 40 second flight. But work on your transition to assure that you do not loose height after you reach the maximum height. To assure good transition, experiment with your launch and bank angles. Start with what both I and Glidiator suggested in the discussions above.

Glidiator

Thanks KK for the appreciation. Have built and flown many HLG / CLG- but they were just for fun flying with accurate construction and basic balancing. Frankly this was my first serious competitive CLG trimming and flying session. Thanks to Free Flight's detailed trimming instructions - learnt a lot.
CLG as a category can be very engrossing and satisfying as flights are sufficiently long. Will now aim for that minute mark. If AUW is reduced the sink rate will surely reduce and give longer duration. The trade off is between strength / stiffness of components and weight. This is where carbon fuselage helps.

Free Flight - this is what my model has
Washin tab on port wing TE
Small Elevator tab
Rudder is fixed on right side of fuselage- not on top centreline. Giving the rudder a bit of an offset angle is done in rubber power too. There is a small rudder tab on left too.
Stab tilt was given by twisting tail boom. Now have a good idea how much tilt to give - when viewed from front - the stab  tilt is visible clearly — just that little up is all that seems to work well.

Also realised trim that works well for strong wind conditions may not be ideal in still air.

Lot of scope to experiment - learn - and improve.




Free Flight

Glidiator, you are most welcome. I am glad that the trimming details were helpful. You will hit close to a minute very soon, similar to my prediction of your 40 second flights. Since, you are not competing for prize, experiment with the FAI rubber that you have. Suggest 2 loops of 1/8 rubber only 7 inches long. Pull to the full strength. Watch what height it gets to, where the thermals are present.

Something to think about: Unlike indoor flying where weight is almost half the battle, there is a minimum weight that outdoor models need. The winner champions here ( 6 flights in succession at max which is two minutes) are all around 0.4 grams per wing square inch area. Much lower wing loading (lighter model) is only good for still air flights. Of course, on the day of competition, the winds are almost (Murphy's Law) around 5 to 9 miles per hour. Very light CLG almost get blown away like a potato chip in a windstorm.

All of the competitors that I have had the pleasure to talk and fly with, say to now concentrate on one thing: Learn to "pick the air" . Must launch in a thermal. That can be a new thread several pages long, and I ALWAYS stumble. The trick they showed me was, launch when the experts launch, as they have sensed the thermal. 

Thought I would share my experience.

Glidiator

Yes FF— lot of basic physics in action. You need that minimum weight to translate the catapult force into acceleration. — which is why you can throw a tennis ball further than a ball of cotton - though the force is same - the mass is required.
Learning to read and pick the air can only come with on field experience
Will use TAN rubber and see performance.
Have a bunch of CLGs - never seriously trimmed and flown. -  used as models to display at workshops.
Will get them in the air now that the taste of CLG has triggered a new addiction.
Will also repair an old IHC Interceptor - folding wing CLG - and fly.
A good way to be airborne since indoor spaces are restricted and difficult to access due to Corona.

All participants - 48 hrs to go to get that Early Bird kit.
Just Do It!!!!!!

Free Flight

"Have a bunch of CLGs - never seriously trimmed and flown. -  used as models to display at workshops.
Will get them in the air now that the taste of CLG has triggered a new addiction.
Will also repair an old IHC Interceptor - folding wing CLG - and fly."

Glad you caught this bug.

All other contestants: I am sure you too will catch the bug. Post a quick video and pick up the Tiny Tot. Most of all enjoy.


K K Iyer

Replacement kit for Hitesh ready. 6gms!


SI74

I thought my entry would the last , as if so , I would stand a chance to win in terms of duration ;) . But since no one has dared yet , I thought , why not be the first ? :) instead . ( And I could not resist the additional perks offered by Glidiator :) ) And here it is -23 Sec from the top ( the guy who shot the video didn't take launch and transition , my bad ) So it may be counted as 1-2 Sec more :) right ? Iyer sir ? Anyways , I think I deserve a prize as the first contestant to post ;) . Thanks Iyer sir and Freeflight for the proper guidance . Used only 3 rubber bands as I couldnot stretch my arms beyond that .


SI74

#267
Another shot

WeekendFlyer

Congratulations to the student who learned so well from the teachers who guided so wisely  :salute:

I think similar results will follow.

We will have some good competition amongst us.

K K Iyer

Weekendflyer sent a msg 'glides ok but dives under full power'

Asked him to add a 1cm piece of matchstick as shown in the pic.

Anyone having trimming problems, please msg me on Whatsapp, preferably with a short video clip showing the model's behaviour.


Free Flight

S174: Congratulations. Wonderful job. So you passed the 20 second mark in both the videos. Your glider looks good in the photo. Very nice design on the wing. So are you having fun? Enjoying?

Looks like you need a very tiny tiny bit of clay on the nose. Start very small, as the stall is quite evident. If your CG is in the correct location, then, I would have sanded the the elevator tab just a bit with a nail file. But that is tricky, you too can do it after you gain some experience. For now just start adding very small amount amount of clay at nose, size of a black ant, Fly each time and see if it takes out the stall. Then let us see your new video.

I am so happy to see your flights.  Congratulations once again. Glad you took the first stab of a full launch video.  

Free Flight

S174: Very happy to hear you say " Used only 3 rubber bands as I could not stretch my arms beyond that" .  Brilliant !
You are now gaining experience. Correct move.  We are allowed 9 inches of maximum rubber length when we compete. But all of us use anywhere from 6 to 7.5 inches only for the same reason.

Another thing to note is that I take at least three  to five rubber band sticks to the field. After about 5 or 6 launches, rubber gets "tired" so you do not get a full height. So I use the next rubber band stick.

After you stall is corrected, may want to experiment with a thicker rubber band. Or use two loops of rubber band in parallel. Will post a picture.

If you guys  had the tan rubber, your launch height would increase by 50 percent. But for this competition, you are not to use it as  it has to be same for everyone.

Free Flight

Dear All: Looking forward to your videos. I will be very happy when all of you cross the 20 second mark and as much as Glidiator and my videos reaching the 40 second mark.

Welcome to the world of CLG flying.

K K Iyer

Here's SI74's latest video of his test glide.
The BEST test glide I've seen.
Better than mine  :banghead:

It is 12+ seconds, or equivalent to a 24+ seconds catapult flight.
And it's just a simple test glide, not even a full power hand launch!
Just correct CG, correct trim, correct launch angle, correct launch speed.

At last I'm starting to see the results of my years of effort to popularise Chuck Gliders as the ideal introduction to this hobby.

Thank you, Doc!




Free Flight

#274
That is a truly good glide video. Your glide test is correct, raises the nose a bit and turns left. This is the first step before catapulting. Then only you are ready to catapult. In the catapult video, you have a clear stall. So even though your glide is GREAT, NOW  starts trimming in glide portion of the catapult launch. Keep at it as suggested above and cross that 40 second mark.

To all: you must rejoice with your hard work paying off. But remember, you will see that in your work life, todays Outstanding work is tomorrows Expected. Do not stop even you cross 20 second mark. go for 40 seconds, then 60 seconds then what we call here a MAX, 120 seconds. Do not stop.  Aim higher and be the best you can be. Good Luck wishes to you all.