@vishalrao,

sir, first and foremost, hats off  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   

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. 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!   

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:

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