First scratchbuilt trainer stick, need help fixing it

Started by amit_delhi, May 18, 2012, 10:08:07 AM

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amit_delhi

Yesterday I applied the 25% diluted Fevicol SH with Tissue Paper treatment over my thermocol wing, and oh...boy...what amazing results...For 38" wingspan and 8" chord, it added only 40gms as extra weight and the wing has became like rock.

Also cut the wing in half, added an angle in middle by sanding thermocol than used 2 minutes araldite epoxy to join again. Got a nice 2" diethral on both side wings.

Thanks for this amazing technique.....

amit_delhi

This is best wing construction method I got till now, specially for beginners and where weight and cost is a concern. For rs. 30 we can make wing up to 76" wingspan and up to 12" chord. And the maximum weight of wing for 76" wingspan and 12" chord will not be more than 200gms.

My wing was 38" wingspan and 8" chord and its weight is 80gms.

Below are steps I took, if any thing is missing or wrong, Roopesh sir please correct it:

1. Made 25% diluted Fevicol SH solution. For 38" wing span and 8" Chord, take about 10 tablespoon of Fevicol SH and add 30 tablespoon of water. Mix it thoroughly. While applying this solution also keep it mixing as the heavy Fevicol keeps on depositing in the bottom.

2. Took Tissue Paper and lay it flat on wing, took a 2" brush and apply in one direction only. Its important that you apply it in one direction. Do not apply on the whole length at once, apply in batches of 2" chord then again move forward and apply on next 2" chord.

3. Insert 2 wire skewers and attach on both sides of the wing to hold it while applying glue.

4. After first covering of entire wing is complete, let it dry under fan, it will dry in 15 minutes.

5. Then add 2nd layers of Tissue Papers covering the entire area. Dry again under fan.

You will be amazed with the results.

roopeshkrishna

Amit.. you are sure.. its simple but gives us amazing results.. and once you got the idea, theres no any restrictions.. can make anything to anything, from a hand launch glider to 6 meter long ship.. will last for a life time.. can repair easily.. can paint it easily.. reshape.. anything.. and happy to know my simple idea came utility for you all.. will add a nice video of construction.. have nice flights..  :hatsoff:
Phoenix.........

amit_delhi

Ready for maiden flight today.

amit_delhi

We tried to fly it today. Lance did the maiden flight.

It took off for just 3-4 feet and just landed. There are few modification suggested by Lance:

1. Increase the elevator control surface as it is not sufficient for taking off. (It was mistake on my part, I changed the original plan and reduced the control surfaces to reduce weight because of ignorance, will stick to the original plan now)

2. Change landing gear, its very soft and bends easily even while taxing.

Also planning to add 5" wing part on both sites with an angle so give this wing a polyhedral shape.

Using 2S 610MAH battery and hobbyking AXN 1100kv motor. Total AUW is 383gms. Guys need help what other issues may be with this trainer spad stick?

roopeshkrishna

Amit, increase the angle of attack, of main wing a little.. and as you mentioned, increase, the throw.. :thumbsup:
Phoenix.........

roopeshkrishna

Amit.. please wrap the RX and battery with thin foam.. always useful.. :salute:
Phoenix.........

R C

Hi Amit,

I also have a similar kind of stick, which i had built.
Wingspan - 40 inch
Cord - 8 inch
Fuse - 30 inch
Motor - CF2822
Prop - 9x6
Battery - 3 cell 2200mah
ESC - 30 A

Wing made from Thermacol covered with cloth and i have reinforced the wing by adding balsa spar and balsa leading edge, total weight of the model including the electonics is 630 grams.
Fuse made of 15x15 mm stick and the tail is from a crashed Piper Cub.

Few pics and video.
--o-o-Ộ-o-o--   --o-o-Ộ-o-o--   --o-o-Ộ-o-o--

R C

pics
--o-o-Ộ-o-o--   --o-o-Ộ-o-o--   --o-o-Ộ-o-o--

R C

--o-o-Ộ-o-o--   --o-o-Ộ-o-o--   --o-o-Ộ-o-o--

R C

--o-o-Ộ-o-o--   --o-o-Ộ-o-o--   --o-o-Ộ-o-o--

gbisht

Hi RC,

Very Nice build and flying Videos ....

What Battery you are using ?? can you send me the link ??
and what wood you have used in  your fuselage ?? is it normal wood stick or anything special ?
HSP 1/10 Nitro Tyrannosaurus Off-Road Truck
Thunder Tiger 1/10 SSK V2 Nitro Truck with Radio
HK-300 3 Channel 2.4ghz FHSS Ground Radio
Turnigy 9x 8-Channel
HK-250GT

R C

Thanks gbisht,

I have used Turnigy 3 cell 2200mah and i have used normal wood stick, i think it is called bidding wood.
:)
--o-o-Ộ-o-o--   --o-o-Ộ-o-o--   --o-o-Ộ-o-o--

gbisht

It is a heavy Battery, what is plane Total Weight ?
HSP 1/10 Nitro Tyrannosaurus Off-Road Truck
Thunder Tiger 1/10 SSK V2 Nitro Truck with Radio
HK-300 3 Channel 2.4ghz FHSS Ground Radio
Turnigy 9x 8-Channel
HK-250GT

manojswizera

@ Gbisht
RC has already mentioned its total wt is  630 gms  :)
Russ-40 Trainer, Mr.moss, Pushler, Skysurfer, Mugi , F-22, Red swan, Xtra-300, redfury, flying mantaray.

amit_delhi

Roopesh Sir,

Following these steps:

1. increase the "angle of attack" of main wing
2. increase the "throw"
3. wrap the RX and battery with thin foam

"angle of attack" and "throw" are not very familiar words to me, searching and reading more about these and will change as suggested.

RC Sir, your trainer stick is very similar. Difference being battery as I want to stick to 2S for sometime as I've bought 4 of them, just want to use them.

Another difference your Wingspan and elevator width ratio is about 1:4, in my plane it is looking like 1:8

Your landing gear is made from cycle spoke? I had issues with my landing gear yesterday, they just fall flat and one prop broke because of that. Will use cycle spoke now for landing gear.

amit_delhi

I can sand the rear part of wing base to increase angle of attack.

I have put control horn 1" behind the LE of elevator surface, can I increase the throw by moving it near to LE? What should be the optimal placement of control horns?

satz flying

Trust yourself

roopeshkrishna

Amit.. hope you got the facts about angle of attack.. and please fix the control horn exactly at the point of pivoting.. if not throw at one side will be higher and one side very less.. and stress will increas at one side.. it is easy to increase the throw of the control surface either by increasing the length of the servo arm, and by decreasing the control horn attached to the surface.. a radio with DR (Dual Rate) function will help lots.. a radio with ATV (Arm Travel) also helps.. you can insert the control rod, from servo, to the possible innermost hole on the control horn on the control surface.. this increases the throw.. and, another easy method is increasing the size of control surface.. but..yes.. weight also increases..  :thumbsup:

RC.. its a nice craft.. inspiring.. :hatsoff:
Phoenix.........

R C

--o-o-Ộ-o-o--   --o-o-Ộ-o-o--   --o-o-Ộ-o-o--

amit_delhi

Hi Guys,

Yesterday we tried to fly it again after doing the modifications.

I have increased the Wingspan by 10", added 5" wing on both sides to give it a polyhedral shape.

Increased the control surfaces, increased the throw, increased the angle of attack. Using 2S 610MAH battery with 10 X 6 prop and AX 2308N 1100kv brushless Micro Motor http://www.hobbyking.com/hobbycity/store/uh_viewitem.asp?idproduct=5429, CG was correct, controls were very sensitive, just a slight touch of the stick was sufficient.

It was under powered, I checked the motor thrust data from this page:

http://thehobbyshop.in/index.php?main_page=product_info&products_id=8

What should be the max thrust of this motor for 2S and 10 X 6 prop according to this link?

I am attaching the flight video as well, please let me know your opinion on its flight....and  :giggle: subsequent crash..It was very windy also yesterday.

amit_delhi

Flight video of Taxing and First Flight








Cant post videos so they are visible here instead of going to the link.

[Admin Note] Youtube links fixed... use the youtube.com/watch?v=XXXXXX format

amit_delhi


Boom stick broke in crash

amit_delhi

#48
 :thanks: for making me come this far...I am happy that it flew, dosnt matter even if for 10 secs only. I cant thank you enough Lance @theleabres...

Experts / Seniors..... what should be my next course of action:

Change the motor / Reduce weight (looking difficult to me) / Any other changes....???

Ashta

Amit, every thing looks good on your plane except power.
You need 80 -100 W power to fly it comfortably.
2cell, 600mah may be too weak to sustain that much current.

Best may be change to 3cell say 1300mAh and 10X6 prop. motor can be the same.

You can't be first because you do not know!