RC India

I had been looking at dried areca leaves for a long time believing it would be a good material for chuck gliders for children. And the recent 1 minute glider competition kept the fire alive.
I got some time to spare yesterday and I went to store looking for areca leaf plates. It is light weight (though not as much as balsa), sturdy and pressed into flat plates. So I guess the material can be bent and curved by wetting and drying.

Drew a glider shape on one of the plates, cut it, sanded a bit and little hot glue made it look a plane. It takes hard landings well, and a couple of 40 feet nose dive to ground. Only the hot glue gave up at the wing joint after the last 40 feet dive. A dab of hot glue again, it will be as good as new.

// I am not experienced with building chuck gliders. My plane dint flew right. There was too many nose dives and rolls. I believe experienced members can make this fly a lot better //

The areca leaf plate has a average thickness of 4mm. The plate size I bought has usable diameter of 24 cms without the bended edges.
The plane has flat polyhedral wing.
wingspan: 29 cms.
fuselage: 24 cms.
AUW: 16 grams. / is it too heavy for this size planes? /

It did not need a nose weight for gentle throws but I was not able to throw high, so added 1 rupee coin (4 grams) for hard throw which resulted in nose dives. I will try to fly it after I curve the wings, sand more to reduce weight and find right cg.
Here are some pictures:
(https://i.imgur.com/6aSfZT1.jpg)
(https://i.imgur.com/XoZ6hDO.jpg)
(https://i.imgur.com/OjFjyDt.jpg)
(https://i.imgur.com/KIArllp.jpg)

@ajay sarwan,
Excellent effort  {:)}

For chuck gliders balsa of 6oz/cuft is desirable, but hard to get.
What we get is usually ~9oz/cuft.
Check your arecanut material’s density.

16gms for a 12” span is an ok starting point.
For this size, 4mm thickness not required, 2-3mm is enough.
If you taper the rear 75% of the wing to about 1mm at the trailing edge, it’ll save some weight.
Avoid hot glue. It’s too heavy. Use CA like Fevikwik.
Best wishes for further experiments...


Edit: Oops. Serious error.
6lbs/cft, not oz!

The FPG9 ( Foam Plate Glider) uses a 9 inch dia foam plate. I have been using same template with a 12 inch foamplate -- just extend the outline to the edge of the plate.  This is a no fail flyer for beginners. use a 50p coin as nose weight.
The areca sheath plate has same configuration -- so perhaps if you use the FPG template it may fly decently.
FPG template available on net easily.
This will be an ecofriendly option inlieu of a foam plate. Must try this out
Anant

Also the upward curvature of the plate edge acts as wing tip sharklets that give added stability.

The FPG is basically a flying wing

Thank you gentlemen for the advises.

I sanded the rear 75% of the wing so that the trailing edge is sharp, added a dihedral, cut the wing tips into triangles and reduced the fuselage height at the tail to reduce weight. It flies better now.
(https://i.imgur.com/RbY8odf.jpg)
(https://imgur.com/2UimdkZ.jpg)



I will definitely try the FGP9 and reply how it went.

I have one doubt though, This plane is good on gentle throws, flies in a straight line and gradual decrease in altitude. But when I throw hard, it does not fly well. I am trying to throw the glider hard at a steep angle so that it will gain altitude and glide back down slowly, but it flies in ballistic path. I cannot find why it happens?

What’s a ballistic path?
It loops?
Or dives?

Also, what’s the density?

One thing to be checked is the profile of the surfaces. I have seen that the flat part of the areca plate can have warps /bends that will affect flight characteristics.

when I throw hard almost vertically with elevator up or straight, It flies in the path like in the image.
(https://i.imgur.com/QPz0KT3.gif)

so, when i throw with down elevator, the plane nose dives.

I could not find the density. My scale is not accurate enough.
I will try to find it tomorrow when shops open.

The are no warps or bends in the plane.
//Even if there are bends, pressing it with hot iron box straightens the material.//

@ajay sarwan,
Congratulations.
On reaching the second test of Chuck Glider flying,
Having crossed the first test (finding an approximate CG and getting a smooth glide of 30-40 feet, without stalls and dives). You did pass that test, no? Else you return to stage one!

The second test, or stage, is how to avoid looping in a full power launch.
This has two parts
How to launch
How to avoid looping.

The launch for the first stage is from shoulder height, model held just behind the CG, nose pointed slightly down, aimed at a spot on the ground about 50’ away, and pushed gently straight, without your hand describing an arc.

The power launch is utterly different except for holding the model at the same place, ie, just behind CG.
(I’m assuming you are right handed)
Hold the model lightly.
Keep your wrist loose. Don’t cock it.
Swing your LEFT hand up about 45degrees, while swinging your RIGHT hand down as low and as far back as you can.
Are you holding the model loosely? Is your wrist loose and not cocked?
If so, the model should be banked RIGHT A LOT MORE THAN 90 degrees and pointing UP ~45 deg.
The action is like a discuss throw.
NO ELBOW BEND. ALL JOINTS OF RIGHT HAND LOOSE, FROM SHOULDER TO FINGERS.
Stand facing the wind, wind up your torso till your left hand points into the wind and 45 deg high.
The right hand will be more than 180 deg away, behind your back.
To launch, swing your whole upper body hard left, release the model when your right hand is about horizontal. At release the model should be banked right about 45 deg and pointed up about 45 deg, and going a little to the right of the incoming wind..

This is the way to launch, and enter the second stage of how to cure the looping!

Enough for one post.
I’m copying this to my ‘1st Chuck’ thread, so that others too can see it.

I’ll post ‘how to cure looping’ if there’s enough interest ...

BTW, if your scales are not accurate enough, weigh 10 arecanut plates and divide by 10  ;D

Big mistake in my reply #1

Balsa 6 lbs/ cft, not oz!

And no one noticed it ?  :headscratch:

@KK
Went on the net to see what should be the ideal wing loading for an efficient HLG.
Came across this piece. Could copy only this part -- rest needed payment. This talks of wing load of 1oz per 100 sq inch of wing area. Problem is being used to metric system it is difficult to relate to the FPS system an appreciate how heavy an Oz is. In fact I have an inch to mm conversion table on my mobile. Difficult to appreciate how much mm is 3/32 of an inch without a conversion table. And rubber comes in such dimensions.

 Excerpt of that piece for those interested.
Hand launch glider airfoils
HLGs are simple flying machines; it’s the flying indoor and the digital stopwatch thatcomplicates things. Those factors separate the theorist from the flyers….and the bullshitfrom the real world. I have spent ! years in the real world of the Hand Launch Glider. I have won bothindoor and outdoor hand launch at the "eal #ationals$ I have held both indoor andoutdoor records many$ many times. I held both indoor and outdoor records for about %!years after I &uit flying hand launch. 'y two sons won the #ationals and still hold (unior and senior hand launch records they set in the %)*!s. 'y point in all that is; you never once beat me in any HLG contest. +nly those who beat me can prove I’m wrong. ,d-obot beat me once$ ic/ 0eterson beat me twice$ Lee Hines beat me once$ and 1enHappersett beat me once. ,ach time I learned more than they did$ and came bac/ better  prepared$ so can you. In the real world of serious Indoor Hand Launch Glider competition$
 Weight
iswhere it’s at.
Weight is the single most important factor determining glider  performance.
 2eight is also the second and third most important factors. 2hen a glider is over weight there is nothing that will save it. Indoors there is nomagic strong enough to rescue a poorly built glider. These new digital stopwatches arenot impressed by manure$ no matter how deep it’s piled.
 The ideal weight for a conventional hand launch glider is about 1 oz per 100- sq. in. of wing area.
2indy weather outdoor gliders are (ust barely competitive at %. o3. per %!!4s&. in. of wing loading. 5nything heavier and you might (ust as well be throwing golf balls at the thermals. +nly after you have convinced your self that weight is by far the most important factor in small model performance$ only then can you turn your attention to the minor details. rag is the
 fourth
 most important thing to a HLG. rag is a relatively minor itemcompared to weight.
Thou shall never add any drag reduction details that increase flying weight.
6nless of course you need to increase weight for a good reason. The only good reason I/now of is to get the model higher. Indoors you should fly a model that uses all of theavailable ceiling height. 7ut remember that heavier models have a
difficult
 tas/ inslowing down and ma/ing that first turn at the top. 7etter to be a bit too light rather thana bit too heavy.
I.
 
 In the climb portion of the fligh

A bit garbled in the copy paste

@KK sir: WOW. No wonder my plane flew bad, because I threw it like I throw a ball. This plane flies just about 30 feet, so I will try to cover 40 feet before entering the second stage.

@glidiator: sir, If you are using android, you might find this app usefull for conversion.
https://play.google.com/store/apps/details?id=kr.sira.unit (https://play.google.com/store/apps/details?id=kr.sira.unit)

And I read the excerpt few days ago on the website. Since your post was garbled when pasted, People who wants to read can click on this link.
http://www.modelresearchlabs.com/hand_launch_glider_airfoils.htm (http://www.modelresearchlabs.com/hand_launch_glider_airfoils.htm)

@glidiator,
@ajay sarwan,


Simple.
1oz/100sqin is about 1.5oz/sqft
That I think is IMPOSSIBLE, except maybe for world champs indoor chucks. Even that I doubt.
My (now lost) 1st Chuck was finally 9gms on under 18 sqin area. Or 2.5oz/sqft.
Achieving that needed a lot of wood selection and a LOT of sanding, probably well beyond the capability of a newcomer..

If Arecanaut can get below 5oz/150gms per sqft wing loading, I’ll consider it a good start.
Should aim for 3oz/90gm per sqft of wing area.

Ajay, you have to do whatever it takes to find out how many lbs/cft that arecanut weighs!
Regards

@KK sir, I am working on it.

@ kk sir, I am having a hard time finding the density.

A 3millimeter thick arecanut sheet in 15 sq.cm dimension weighs 20 grams.

My calculations were way off the expectation.

But fortunately someone has already done the work.

https://bioinfopublication.org/files/articles/8_60_10_IJAS.pdf (https://bioinfopublication.org/files/articles/8_60_10_IJAS.pdf)

This research paper on arecanut sheath says, the bulk density is 0.8 gcc. I guess gcc stands for grams per cubic centimeter.

Considering average Balsa density is 0.137 grams per cubic centimeter,  arecanut is almost 8 times heavier than balsa.  :( :banghead:

And the plates are made from areacanut tree sheaths, not from leaves.

See my 1st chuck thread.
See if you can make one in 9-10 gms...

I tried making the tich in areca sheath. It came out heavy at 17 grams (sanded + two coats of polish) and does not fly well too.
And the material has a natural bend and does not stay straight for long. While the foam Tich, flew almost to 10 seconds,
I had a hard time making areca tich fly straight for 10 feet.

Although areca looked like a promising cheap substitute for balsa at first, it is not worth the time or effort.
Please consider the thread closed.

Thanks to K K Iyer and Glidiator for taking interest and guiding.

@ ajay sarwan,

It was a GOOD EFFORT.

Nowthat my son, daughter in law and grandson have gone back, and my wife will be on tour from Sunday, I can make and send you a small balsa kit. Next week.

Regards

Its very kind of you to send me a kit, sir.

Please let me pay for the shipping at least. :)
Thanks.

Ajay,

Appreciate your efforts to innovate and scratch build. It would have been a good learning experience. I always say failure teaches you more than success.
Will add to KKs encouragement kit and send one to you too. Please PM your address.

Wow. This is the best time of the year for me.
Thank you glidiator sir.
Such gestures definitely makes me want to show the same kind of encouragement to fellow newbies.