Here is an Extra Spad build...
Since the timeline for the sweeps gives some 'extra' time, I thought of doing an Extra build. (Although I started the wing sometime back)
The spad plan on STTB gave me a starting point. I've tinkered with dimensions a little and used 5mm coro for the fuse and the stabs. The wings are made with 2 mm coro, The wingspan for the SPAD is 54 inch but I;m doing a 48 inch version.
The Extra seems to be a fairly acrobatic craft (though I still don't know how to xecute a loop in the perfect vertical plane :D)...
I wanted to use a semi symmetric airfoil, so opted for a spar+rib design. Could've used 5mm coro on one side and 2 mm on another to do a semi symmetrical wing but wanted to checkout cutting ribs in coro (it's a pain, I know now).
Here are some pictures...
More photos
Sure looking good! Why so kanjoos on the ribs, put a few more :D
Thank you Rai sir,
The wing is now closed :D, so can't add more ribs without taking it apart...perhaps in the next build; cutting the ribs was the most difficult part, and post the cutting, I tried everything from sanding to planing to chiseling to shape the coro using a paper cutter, nothing really works well :(
Here are some pics of the closed wing and the empennage
And here is the first scar!
I was trying to glide test the wing by attaching a MDF strip (to behave like a fuselage), balancing the CG at the spar and launching it. While I could see some glide, the side of the wing struck an obstacle :(
Girish sir beautiful and Strong build..
Many thanks swizera for the compliments.
Dear Grish
Very good build
very good and colorfull build.... {:)} , pl post the side view of wing ( for airfoil look).
Thank you kamaraj ji, the real goodness will only be when and if it flies well or it will be in the 'hanger' (hung from a wall)...:D
Thanks Mjet, sure I'll be posting the side view soon illustrating the aerofoil section...
@Girish.. These models with symmetrical aerofoils will never glide . its the airspeed and the elevator throw that will guide it. :) . u r soon gonna have some real fun . I have been scratch building from quite long and that justifies the diff in aeromodeller building from scratch and aerobuilder assembling arf
. hehe.long live aero modellers.
Absolutely Sujith, symmetrical aerofoils have almost no authority of their own in providing lift, it's the elevator throw, for this build I'm considering a semi symmetric one which probably caused whatever little glide...
The aileron template was chosen based on some resources on the internet and a causal look on the spad extra wing in the original build. I am using a 10 inch chord with 18% thickness (high drag) although the extra should be a fast flyer for obvious reason, but I need some slowness to be able to control this thing (for sure I am expecting loads of fun on the field..hehe)... I am sure with so many resources and people on RCI, I will end up being in the aeromodeller clan ;)
Once i finish off the frame, I will need some help from builders like yourself in considering a power system. I am at the moment considering a 2822 1400Kv with a 8x4.5 prop, burning about 30A on a 2200 LiPo, but I also have the option of mounting a .46 nitro with a larger prop (and there will be CG changes :(). Your recommendations will be of help
Honestly Girish, you can't write 2822 & 46 in the same line.
Even a 3548 has the power of a 25~30. What soes STTB say? 46? Then stick with that, or dramatically reduce the weight
Thank you Sanjay sir. Get that totally, they're miles apart. I will stick to the specs till I gain more experience to experiment. although I have reduced the weight and the size. Many thanks for the inputs.
Quote from: girishsarwal on March 05, 2013, 03:35:46 PM
Absolutely Sujith, symmetrical aerofoils have almost no authority of their own in providing lift, it's the elevator throw, for this build I'm considering a semi symmetric one which probably caused whatever little glide...
The aileron template was chosen based on some resources on the internet and a causal look on the spad extra wing in the original build. I am using a 10 inch chord with 18% thickness (high drag) although the extra should be a fast flyer for obvious reason, but I need some slowness to be able to control this thing (for sure I am expecting loads of fun on the field..hehe)... I am sure with so many resources and people on RCI, I will end up being in the aeromodeller clan ;)
Once i finish off the frame, I will need some help from builders like yourself in considering a power system. I am at the moment considering a 2822 1400Kv with a 8x4.5 prop, burning about 30A on a 2200 LiPo, but I also have the option of mounting a .46 nitro with a larger prop (and there will be CG changes :(). Your recommendations will be of help
18% thickness is too much.. would be good if its 10-12%. these are fast flying models.. seconly power system seems to me perfect for a model weighing ~ 1kg..
but as suggested stick to SPAD's build.. ( u can do ur own R& D though).. but 2822 is nowhere near a 46 nitro motor..
i recently converted an old trusted plane ( baught it when i was a beginner) .. it had a 2822 motor on it.. now glow powered it with a ASP 12 size engine and 7 XX 5 prop.. and still its over powered.. somehow.. notro motors generate more power in the same line
Thank you Sujith. I will stick to the 46 for this build.
For your eyes Mjet
Well, although you said mjet,I have had a peek. Looks vrry very good
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thanks girish, clean and good finish :hatsoff:
it looks like semi symmetrical, but extra may need symmetrical profile.
Thank you both; this is totally an experiment :D. I have also tried to make a rectangular fuselage for this one 5.5 inch across by 4 inch height strengthened with 2mm ply firewall (.46 mounted) and coro fuse formers :D. Pics coming soon
waiting for Fuse Pics. 2 mm ply is sufficient for .46 engine? i have used 12 mm ply in my SPAD for .46 engine :banghead:
Yups, 2mm itself was not going to hold the engine. so this is what I've done
1. There is another 2 mm doubler at the back where the engine mount bolts in, washers used of course. The doubler grain runs perpendicular. Teak ply used.
2. Wedges on both side edges where firewall meets the coro to increase surface area for glue. Held tight using gclamps for gluing.
3. Tongue and groove in the coro at the bottom. The ply tongues into the groove for gluing. Everything glued using epoxy (Fevitite).
The joint feels pretty strong. I haven't started the engine yet; will be doing it this week and update. Pics upload will be sooner
Pictures of the fuse and the engine mount
I have a feeling the wing span is small... :headscratch: :banghead:
This build was lost somewhere, gathering dust...
After some positive motivation from sanjay sir, and a random shuffling of items in my hangar, this build had been revived...Fixed up parts of the turtle deck today for vinyl covering...
The firewall has been replaced with something more durable
close ups of the L brackets used to mount the turtle deck formers
Coming along well :D
Don't try to test the strength of the turtle deck supports - by landing inverted :rofl:
I wish I was that skilled sir, I wouldn't have given a darn to the deck ;)
Request the mods to please move this thread to nitro planes section...
The turtle deck completed, and covered in vinyl, hot air shrunk
Front canopy...
I need some lessons in neatness!
The wide front looks weird; and it looks more like a boat; but if I'm envisioning it right, I am hoping this will end up looking close to the original
Pretty neat :D
Looks like i need to come and visit yo girish to fly this beauty, what say
Thank you sanjay sir...your wishes appreciation and guidance keep me going...
Gusty sir...neki aur pooch pooch...when do we have the honour of you visiting us...the whole rcbolt gang...trust me sir...it's long due...
Nothing wrong with a little b(l)oat.
Especially with a 'turtle'deck.
Fly it before Gusty gets there.
His style is overhead keel, underslung mast...
(Just saw he is giving away a Tx/rx. Good deed)
Quote from: K K Iyer on March 25, 2014, 11:14:14 PM
Fly it before Gusty gets there.
His style is overhead keel, underslung mast...
Now Gusty cannot blame me anymore. :rofl:
Hahahah... I built the Extra to move on from level flying but guess I need more practice before I can do justice to this...Gusty sir sure can take it on a joyride, upside down while we go head over heels on his flying style :hatsoff:
The original canopy I made wouldn't fit well after covering, so changed it into two parts, the engine cover is now separate...
Two 2" wide stripes of white vinyl will run by the sides, along the length of the fuse, to cover up the untrimmed vinyl
A text book lesson in coro building
Thanks iwincar,
I hope the results are equally corroborating :)
Wow Girish, cool man {:)} Please try to keep the AUW to the minimum.
Thanks Sam,
I am at ~2.4 Kg AUW at the moment. the cage structure with coro has significantly reduced the weight. A .46 may just cut through but a .55 size would have been the right engine for this build... (if you go back a few posts, i was putting a 2830 motor or something similar... :giggle: :giggle: :giggle:)
I realize this is no more a SPAD, its a CPAD, Complicated Plastic Airplane Design... :giggle:
55, yes. A big prop will be good. Will fly on a 46, pretty well too at that, but for what it is supposed to do, a bigger prop is better I think
Hmm.. 2.4 is a bit on the heavy side for this bird as correctly spotted by Sanjay bhayya. I know its a bit too late, still for your next build you could consider a less wider fuze. I use bamboo skewers of the right size pushed through coro formers with a touch of epoxy in key spots for strength and rigidity. In your case the landings and cruise speeds will be a bit hot. Awaiting maiden videw (:|~
Yups Sam, completely agree...