RC India

Here's my Avispad pics... Thanks to samlikespad and VC sir for the inspiration.

Modifications from original Avispad: No dihedral, rudder design, flat bottom airfoil (3mm ply for spar and 3mm skewers along the chord to stiffen base). Wing made from 2mm coro and fuse from 3mm coro.

AUW: 970gms

Motor: EMAX Grand Turbo GT2215/09 Outrunner (http://www.rcdhamaka.com/index.php?main_page=product_info&cPath=100_93&products_id=516)

ESC: 30 Amps (with external BEC)

Battery: Nanotech 3S 2200 mah

Propeller: 9x6 (Hope to change to 10x5 before maiden)

Accessories: FY-30A Flight Stabilization System. Was lying around idle with me so though of putting it in this plane. Hopefully my 8 year old (already mastered the SIM) son will be able to handle it :)

Eagerly waiting for the maiden!

Update: Just realized that "My Avispad (Without Dihedral)" topic would have been more appropriate instead of "Build Log" as there is no build log as such. If the moderator feels so, please change the title.

Nice clean build..Do share your review of the FY-30 A Flight stabilization system later..

Sure Atul! I had used it before on my Sky Surfer but was not happy. It crashed while takeoff and landing  :) I hadn't discovered the exact reason but I think now that the gain in elevator was very high. Hopefully will have a positive experience this time as I really love the concept.

 :goodjob:

how you decorated?

Wow, crafted out very neat! :thumbsup:

Superlative finishing!!! :hatsoff:

Quote from: satz flying on August 17, 2012, 06:06:11 PM
:goodjob:

how you decorated?

Stickers. You get stickers on square foot basis. Just cut the required shape and apply.

Thank you hyd_quads and VC sir!

BTW VC sir, did you get to maiden your Avispad?

Immaculate bird...!! {:)} {:)}

Wow! neat and sweet build  :salute: ... video please  (:|~

Great build vishal, happy flying .........post video

Thank you Tushar, Sameer and Rajesh!

I do hope that this plane flies as good as it looks  8-)

BTW Sameer, where was the CG of your Avispad located?

As far as I remember, I balanced it on the spar.( And as per BEX, it was around 33% cord). Keep a bit heavy to the nose for the maiden and adjust to suite your flying later on. Good luck with the maiden!

Vishal,

No I haven't maidened mine as yet. My CG is located at 1/3 Chord.

Your motor has a max amp rating of 28, you may do well to hike the ESC to at least 40, especially if you are thinking of putting on a 10" prop.

Beautiful build (I know I posted before - just can't help  (:|~) - looks like a shop bought RTF.

i also made coro spad with dihedral wing the auw is around 950 grams can u tell the motor,prop,esc and battery specification

Kamaraj any pictures of the model? That would help.

Thank you Sameer!

VC sir, I haven't tested the amps draw for the motor yet. I think it should be under 28 amps as 10x5 is the specified prop for the motor. Will check the amps draw now.

Kamaraj, please check the first post for my specification. I think it should be good enough.

Looks like I have to remove drishti from the plane before maidening it!  :giggle:

There you go. Hang this from her tail landing gear as you maiden her.

Will be too heavy :) This would be more appropriate I guess...

Vishal, too good built.

can you give steps of making such flawless wing out of coro. main interest is...
> how to strenghten lower wing Base so that it does not curve
> how to give upper wing the required aerofoil shape.

Expecting answer soon. Thanks!!

Practice Saurabh. I have built some 4-5 wings before achieving this. The methodology is same as what you see on spadtothebone site. I have stiffened the bottom by gluing skewers (3mm toothpicks) along chord length at say 8 cm intervals. The best I think if you want to achieve a flat bottom wing is to use 3mm coro for the base. That way, the bottom won't bend when you fold the top.

Here are some tips I can give you to achieve a beautiful wing:

1. Crease and fold the wing top really well before gluing the spar. So that the top sits completely on the bottom (like paper fold). This way, you'll be easily able to fold the top without folding the bottom after you have glued the spar.

2. Shift the spar to say 35% of chord length and keep the height to 10% or less of the chord to be able to work easily. The taller the spar and closer it is to the leading edge, the difficult it is to fold the top.

3. Cut the wing top in to 2 (along the center) when folding. It becomes easier to work than folding the full span length.

Thanks Vishal,
Let me see what best i can do with the tips!!!

Maiden successful!!! Very stable. Just can't describe the joy. I guess I have to eat my own words (http://www.rcindia.org/helis/best-way-to-learn-aero-modelling/msg93643/#msg93643). The joy of flying one's own creation in incomparable.

Videos coming soon. Don't expect much from the videos. Shot by my technically challenged wife :giggle:

Congrats!!!  {:)} awaiting the video.

Here's the video link:
http://www.youtube.com/watch?v=47zhoSyTePE

Conditions: Very windy.

Here's the second day video at the beach:
http://www.youtube.com/watch?v=Nj9BF1AvJdM

Conditions: Dead calm.

Have not removed the voices just to show the excitement!

Absolutely thrilled with this plane! Feel like throwing away all my RTF kits.

Congratulations vishalrao. I love the landing strip without the mud pie of course (the first landing) :D

 ;D Really missed seeing that. Too bad, my landing gear has to be rebuilt. I think having that horizontal strut is not a good idea. Even short pebbles can damage the gear. Had no option as couldn't get m2 bolts here.

Hmmm, will moving the strut a little up help?, or perhaps having a cross bar design; might add a little to the clearance...just an idea...

The strut serves dual purpose. For the wheels to rest on it and support. So moving up will not help.

 {:)} nice flying vishal  :thumbsup: good job! Whats next ?  ;)

Thank you Sameer!

Haven't really thought about next. I'm yet to absorb the fact that I could build a plane that can fly as well as shop RTFs! Just want to enjoy flying this till I get bored  ;D

Bravo! The background chatter makes gives it a realism that is adorable.

I'm thrilled at every plane's FFF, which quads don't have... cool videos!!! :)

Hey Vishal,

Congrats man , very nice and clean build, and good flying too  {:)}

QuoteShot by my technically challenged wife

Hope your wifee havn't read this post  :giggle:

-Vinayak

...a cross member construction might help...

Totally agree on the gravel spoiling the landing gear. I've been toying around with the idea of having a portable runway, something I can roll off like a carpet and take along to the field :D

Very very nice build sir and she is flying very well without dihedral what is the auw  :hatsoff: :hatsoff: :hatsoff:

Quote from: VC on August 20, 2012, 12:11:43 PM
Bravo! The background chatter makes gives it a realism that is adorable.

Thank you VC sir! Yes, the chatter really spices up the video.

Regarding amps draw, for 9x6 prop it was around 22 amps. I checked with 10x7 prop as I didn't have 10x5 and it was still within 28amps. Finally flew with 9x6. Appeared to be very efficient. I think we flew for 10 mins (3/4th throttle. Not very sure but it was not more than 3/4th) and it had drawn about 700 amps.

Quote from: hyd_quads on August 20, 2012, 12:25:27 PM
I'm thrilled at every plane's FFF, which quads don't have... cool videos!!! :)

What is FFF?

Quote from: VinayakR on August 20, 2012, 12:38:33 PM
Hope your wifee havn't read this post  :giggle:

-Vinayak

Thank you Vinayak! She definitely wouldn't mind. She is proud to be technically challenged :)  And I don't mind either! Like we (most of us) are culinarily challenged. It's good to maintain your individuality, else life would be boring if all were of same IQ/interests :)

Quote from: girishsarwal on August 20, 2012, 01:30:09 PM
...a cross member construction might help...

Thank you Girish! I doubt whether it would be easy to achieve. I think the original BEX's idea of landing gear for the Avispad might serve well. The only think I hate is pushing the landing wire inside the fuse sidewalls. I have got an idea now, will see how it works out.

Quote from: kamaraj74 on August 20, 2012, 02:04:28 PM
Very very nice build sir and she is flying very well without dihedral what is the auw  :hatsoff: :hatsoff: :hatsoff:

Thank you Kamaraj! Please don't address me as sir :bow: The AUW is around 970gms.

FFF = fast forward flight (I know the term is generally used for helis..)

I'd love to build a plane one day, as fine as yours.  ;D

Wow great build and flight... Can you please tell me what stabelisation gadget are you using.. I am looking for something similar for my scratch built .. Thanks

FY 30A. Please check the first post Umesh. Actually I have not used the stabilization for most of the flight in the videos. The plane is very stable without the stabilization system itself.

here is the picture

Nice build Kamaraj! Is the landing gear scratch built?

hai vishal,
iam using 3mm aluminium strip, let me know any other option,

auw is 1200 grams
suggest me motor,battery,esc and prop

Hi All,

My previous landing gear was made from GI wires and as forecasted in forum, that was band during landing :banghead:.

For experiment, I have made landing gear from Iron Rods used to support cycle fenders ( 2.5 mm and 4 mm Rods).Specs are same for both design except thickness of rod.

A Nut / Bolt arrangement is provided on TOP ( Gas welding)  , which will be  fitted on ply and two small nut to hold axle of wheels ( Gas welding) . This arrangement  has very good strength.

I don't know , it will work or not .All of you are requested to review this design and suggest(weight- not measured , may be 30-40 Gms apx).

Pictures were taken from Mobile , so sorry for poor quality of pictures.

Regards
Mohan

Quote from: kamaraj74 on August 23, 2012, 04:29:50 PM
hai vishal,
iam using 3mm aluminium strip, let me know any other option,

auw is 1200 grams
suggest me motor,battery,esc and prop

Are you sure it's 3mm? Looks like 2mm. 3mm would be too thick I guess. The reason I asked you is because I wanted to implement the same thing! Do you get flat aluminum sheets or rolled ones? If it's rolled, then I think there would be some work straightening it. How did you cut it?

Regarding your setup, I would recommend this motor:
http://www.rcdhamaka.com/index.php?main_page=product_info&cPath=100_93&products_id=517

...with a 10x5 prop, 30A ESC and 3s 2200 mah battery.

Dear Mohan,

Can't make out clearly from the pic about the fixing mechanism in the top.

While browsing today, I just found this web page:
http://www.foamflyer.info/landinggear.pdf

I think it's a very efficient one to try out.

sorry about thickness it is 2mm i bought from aluminium fabricator shop it is stright and iam using 1.5 inch bolt for wheel mounting

because when it is landing the total shock will be absorbed in the bolt
bolt only bend

Great! Thank you Kamaraj!

iam using following motor and speed controller

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=12919

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=18966

when i connect this all servos working fine and  also motor responding initially

when i give throttle motor does not spin
advise me


Admin Note: Please do not copy paste the same message again.

Make sure your throttle stick is all the way down to the "Full off" position when you connect your battery to esc.

also the trimmer to be on the lowest..... if you have a FS TX 6 ch the left switch is for throttle cut try changing that. ( throttle is 3rd channel - just for info)

I think the landing gear needs to be flexible rather than rigid, so that it absorbs shock and prevent it from transferring to the fuse.. using iron or steel is not a good idea.. aluminium is a better choice as it is light and flexible..

@ vishal can you please post the link to the plans .. thanks

Umeshk, you can find the plans in VC's build log here :
http://www.rcindia.org/electric-planes/avispad-build-log/

Btw, its a very nice build, Vishal!!:) Absolutely clean finish..!

Quote from: kamaraj74 on August 24, 2012, 11:19:36 AM
when i give throttle motor does not spin

Does the motor doesn't respond at all or it stops after some time? Does the ESC keeps on beeping after you connect the power?

Try initializing the throttle range first. Before connecting the power to the ESC, move the throttle to the full open position. Now connect the power to the ESC. You might hear 2-3 beeps and then nothing. Then move the throttle to full down position. You will then hear a beep sequence indicating that the initialization is over. Your motor should then respond to the throttle.

BTW Kamaraj, the motor is just fine for your model. I do hope that you are using 3S and 7x3 prop.

Quote from: umeshk on August 24, 2012, 12:37:40 PM
I think the landing gear needs to be flexible rather than rigid, so that it absorbs shock and prevent it from transferring to the fuse.. using iron or steel is not a good idea.. aluminium is a better choice as it is light and flexible..

Agree! That's the reason my landing gear snapped. Looking at Aluminium option now.

Quote from: S_K on August 24, 2012, 01:07:24 PM
Btw, its a very nice build, Vishal!!:) Absolutely clean finish..!

Thank you S_K!

Thanks friend
as per your instruction i did now it is working thanks a lot

Thanks Vishal

Cheers  ;D

New Landing Gear

Made from stainless cycle spokes. Appears to be springy, but strong enough. Only landing will tell :) Won't crack the fuse for sure in case of hard landing.

Hi Vishal,

Nice design , pl tell me the thickness of spoke. have you tested it ? i will use it in my blue baby.

Regards
Mohan

It's 2mm Mohan. The design is same as in the original Avispad build thread by BEX. The only thing is that instead of inserting the gear into the fuse sidewall, I have inserted it into blocks made out of foam board.

I'm yet to test it!

One way to test it would be to pick up the plane on full load and drop it on a carpeted floor from a height of 3 feet or so. The u/c should not buckle.

 :-\ Scared to do that VC sir! Will wait for the skies to clear and do the landing test  ;D The best part of this design is that (I think) the fuse won't be damaged. At the most the landing gear will bend in case of hard landing.

A cross member can also be added to strengthen the gear but then it'll lose the spring action, transferring all the impact to the fuse.

Nicely done vishal! since you have the ply piece (epoxied or bolted I hope) on both sides, it should hold. But I dont think the extended portion with foam support is going to help much ;)

And hey, thats one mean looking prop!!! is that a sport prop?

Thank you Sameer! Since it's very difficult to make exact hole on the ply same as the spoke dimension, there will be some movement in the landing gear, if they rest only on the ply. The foam board support helps a lot. What I did was drop a few drops of cyano into the landing gear holes (in the foam board) and now they are rock solid. Since the ends are threaded, one can also bolt them on top of the foam board by adding a washer.

The prop is a normal 9x6 electric one Sameer!

Then its time for more videos! ;)

Thanks vishal. Is foam board ( Means Laminated foam ) is available in India   (:|~ ?pl share the Manufacture name and availability.

thanks and Regards

I don't think it's called laminated foam as there is no lamination. It's a homogeneous mass ranging from 2mm to 10mm I think. It's used for making advertisements/standees etc. It's available at many places over here. I think it's called foam board or sun board. Try going to a sticker shop or CNC cutting unit and inquire over there.

Vishal, I think that's a wonderful job, esp the springy foam. I think the washer should really be added, perhaps a rubber one as there will be considerable play during landings, CA probably wouldn't hold metal to foam long

Do you think double sided tape can be used a replacement for the foam, are they the same material? How about using natraj erasers as a substitute, ofcourse keeping a tab on the weight

Also, god forbid, in case of a hard landing and the gear twisting about; since there is quite some play, would it be easy to straighten it out without unmounting?

Thank you girishsarwal! Regarding spring action from foam board, it's not that way. The foam board, unlike it's name is very hard and doesn't offer any movement. The shock absorbing action comes from the vertical movement of the spokes as there is no horizontal strut or member restricting movement of the spokes. Unlike GI/Brass wire, stainless steel cycle spokes have lot of temper and retains the original shape when stressed to some extent.

I hope the attached illustration will explain better.

amazing build.

you will get laminated foam at aero engineering work chennai  web site: aeroworks.co.in

Quote from: manu on August 30, 2012, 05:51:35 AM
amazing build.

Thank you Manu!

Is it aerofoiled shaped ??? if not then lamination is of no use ???

@vishalrao,

sir, first and foremost, hats off  :hatsoff: :hatsoff: to the wonderful work you've done on that build, Endeavors like yours generate opportunities for ideas to be shared, and I thought, I'd share mine ;)

A picture is a thousand (I think more) words and it clearly explains what you meant. I have drawn up some images too to convey what I meant (My formal education had no component of fine arts so the images are not beautiful, only mechanical :)). Additionally by using a washer and nut, the shock can easily be transferred across the area of the foam and dampened.

I totally agree on the steel snapping to its original shape part. After all, it enjoys the privilege of being the most elastic material.

Also attached another image wherein a spring can be used as a horiz strut member introducing elasticity
Cheers!
GS

Well done Vishal! Great looks, great performance   :hatsoff: :hatsoff:

Just one query: Bex used a 2.5 m span, obviously you haven't  ???

Did you scale down from his plans, or use some other?

Best

Sanjay

@girishsarwal Thank you for the pics! Sorry was busy so couldn't reply. I prefer the second method (horizontal spring). Regarding my steel (cycle spoke) landing gear, bad news. It buckled! So now I'm going back with the hobby king landing gear as earlier, without the horizontal strut.

@Sanyay

Thank you Sanjay!

No it's according to the plan (http://2.bp.blogspot.com/_6n6m2YCvlTg/SfbYBLFlQdI/AAAAAAAAAiM/4Ead1FyJ_2c/s1600-h/Avispad+2009+Wing+cutout-724389.jpg). I haven't scaled down.

Update: The plane crashed a few days ago :( The wing cut into 2 when I tried doing some aerobatics! The spar (3mm ply) wasn't strong enough. Now building another one with semi-symmetrical airfoil and stronger spar. Flat-bottom airfoil has too much lift and slow speed. Also putting a bigger and powerful motor :)

Almost ready. Will update soon!

Hi Vishal
Sorry to hear about the crash. And all the best for the new build.

I've had an idea last week while the carpenters were working at home. How would it be to use margin for the spar. This is the same thing that covers up the side faces when board is use to make shutters etc... Honestly, I've never felt a wooden yardstick (one suggested by Spad builders), but I feel margin comes close in terms of strength and weight.

Anyone with experience, please advise.

No problem Vishal! Sad to hear about the wing buckling. Looking forward to seeing Rev. 2!   :thumbsup:

Sanjay

I've built some Spads (posts and build logs in this forum)

I went to a Lumber Shop, and got some wood cut, 1/4 sq., 3 mm sq., 3 mm X 25 mm etc. Cost me Rs. 600, and enough for about 10 Spads!

Dimensions sound very much like that of margin...

@girishsarwal I guess you may be referring to "beading". That's what carpenters call here. I bought one here which is 4mm x 20mm. It's strong enough but heavy also. I guess I'll use that next time. I was also thinking of using 4mm balsa, reinforced with the same strip for half the length (in the middle).

@Sanjay Thanks for the tip!

Hi,

I used this wood strip ( called Beading , used by carenters to cover and close the edges of SUNMICA ) in my AVISPAD in full length, you can found these in various thickness and length. A 48 inch long and 1 inch wide beading will cost only Rs 15- 20.

In my AVISPAD , found weight of 48 inch beading with 6 inch two doublers only 130 gms, pl see the picture.it gives a great strength to wing.

Sorry to hear that Vishal. 4mm doubled cris-crossed ( rock solid if a third piece in the middle) is what I have used. Anything less could be a problem. But if you cant get hold of 4mm, you could use 3mm one two of them flutes lengthwise, and a third smaller one in the middle flutes width wise. Coro gives good strength once you CA them criss-crossed flutewise. You could try many combos of this to find the best one for you.

@Mjet Yes that's what I have with me. Thought it would be heavy. Will try that next time.

@Sameer We don't get 4mm coro here. Have you tried 3mm (3 strips) on any of your models and done bit aerobatics? Would like to try that as well in one of the future builds. What I guess is that they'll be difficult to glue with CA as you won't get exact flat edges on coro strips.

Cheers!

I have tried 3mm (3 pieces) successfully Vishal. And I use CA for gluing the spar pieces together and it holds well especially with a bit of sanding. The strength like I said earlier is from the flutes being opposite to each other. You just try on 4 scrap pieces of 3mm coro strips 1" wide. I would recommend 2 full length 3mm pieces in the middle and 1 or even two slightly smaller pieces in the outer sides for a spar.

And like I said you could try many variations for eg. you could put couple of bamboo skewers in the middle for additional stengthening since you have a non-dihedral wing.

Thank you Sameer! I'll definitely try it in the next wing build. Cutting and working with the ply is pain. If this works out, building the next plane would be real fun :) I'm thinking of using 3mm carbon fibre rod in one of the strips. That would be great then.

Build 2 Video:

http://www.youtube.com/watch?v=0Kqzfpzz7n0

Wow!!! Well done!!! Is it a trainer anymore??? man its time for you to build some thing more sporty....like a stick ;)

LOL. Yes it's definitely not a trainer anymore! Same thing my colleague was telling me at the field. But one thing with this model is that you get the best of both worlds. You can fly slow if you want or race if slow gets boring. I'll stick with this for some time.

sweet! like very sweeet!

Thank you Girish!

Just noticed today that at high speeds, the rudder flutters a lot. I already have three skewers in the rudder. What else can I do?

How about using some struts for the tail assembly. They don't exactly look good but help reduce the flutter.

Doubling up the coro? but that would mean taking off the empennage, complicated.

Thank Girish for the tip! I think I'll go with doubling the coro without taking off the empennage. Have an idea. Let's see how it works out. Thanks again!

Very well built very well done :hatsoff: :hatsoff: