Hi Guys,
I was planning on going on with the thread http://www.rcindia.org/gas-glow-nitro-planes/no-coro-here/ but then with new beginings heres a prewiew of what was done last week.

Hi guys,
Here's my latest build. Again a SPA3D. The first one is still waiting for its maiden flight and I'm sure my bro will be installing the engine and servos soon.


This one too like the first one is made from:
1. 4.6mm multilayered polycarbonate sheet.
2. Aluminium channel
3. 3mm earthing wire
4. For the landing gear I used 5mm stock Aluminium and reinforced it with 0.5mm strip of spring steel.
5. Control horns were cut out from a new tiffin box.
6. Control horn doublers, wing and tail doublers cut out from an old paint bucket cover.
7. Cycle spokes number 6 for control rods
8. Fuel tank made from a hospital disinfectant 250ml rectangular bottle.
9. Main landing gear wheels – Foam wheels      
10. Tail wheel – engine oil seal Hero Honda.
11. Engine mount – Polycarbonate sheet removed from a factory inspection window.
12. Nuts screws and bolts – hardware stores.


Just want to take this oppertunity to thank the people who made this bird come to life.


Engine - courtesy Aaron
Technical knowhow and expert guidance Raghuveer  Bhaiya, Harveer Sir.





This SPAD would not have been made if it were not for
Sandy Bhai for getting me into this hobby, the constant support, and for being my inspiration.
Harveer sir for teaching me flying, being a great mentor and guiding me so that a dream may be realised
Raghuveer Bhaiya for the guidance and words of wisdom
Pritam for being the ever resourceful and helpful gentleman that he is.
Dinesh for spending the long hours on the road for getting the polycarbonate sheets.
Rajneesh for cutting the decals
Namita and Saumya for their patience.
Aaron if it were not for u, this bird would not be taking off.
A lot of friends

So guys this babe belongs to a lot of people.

The Waverunner as I call it took off on Thursday morning 13th of May 2010 at 7.20 Am. Here is the video.


The winds were too much for hovering and we did 3 sorties.
My Instructor and mentor Harveer Singh Sodha flew her and on the final sortie of the day while I had the Tx, with a tail wind we had a deadstick and the plane came down nose first.

Video coming up soon

Damages
Broken Prop and spinner
Broken engine mount
Bent landing gear
Hole in the PC sheet


Today
The Waverunner is ready to fly
3 cheers to coro flying
Doc

the SPAD3D rocks
paint works is cool

Video of the unfortunate crash.

Thanks Anwar,
Was waiting for the video to be pocessed.
Waiting for all the comments.
Doc

Some more photos

Any suggestions guys?

Doc,

I am quite impressed by your build. Only very few people take the extra mile to finish their scratch build to look neat and clean without compromising on the build strength. I would call builds like these as "Superior" Plastic Airplane Design. Your's is one of the good example.

I have something to say on the crash. It looks like the plane almost nose dived vertically. I don't know why the pilot let it do that. Didn't it respond to controls?? Any investigation done on the cause of the crash??

I once built a spad that would not respond to elevator inputs once the engine cut off. That is because the elevator moment (distance of elevator from the CG) is very short and to pitch the airplane it required a lot of force on the elevator (read it as lot of prop wash on elevator).

From your crash I see that the plane is diving vertical so, you should have had good airspeed on the elevators. Further, your tail moment seems to be reasonable. So, even slight deflection on the elevator would have leveled the plane... Just think about it and improvise on your next build.

-Ismail

Hi Doc,

Really nice build, I must say. 

Just had a few questions...

1.) What is this polycarbonate sheet ?
2.) Where did you get it from ?
3.) Does it have flutes? Do you need to insert carbon rod / piano wires so that the sheet does not flex?
4.) How did you make the ailerons ? how did u join the ailerons with the wing?
5.) How do you cut poly sheet ? Using regular file ?
6.) What paint do you use ?

Hi Saurabh,
To answer your questions
1. This is amulti layered polycarbonate sheet that I found jus by chance while I was looking for 4mm coro. It is used to build shed like coverings in houses.
2. I got it from a dealer in Indore who also deals in coro, and acrylic sheets.
3. It has flutes and it does not flex. Being multi layered it is very strong and on the other hand it is light also. But going with the plan I did insert pieces of Earthing wire at the designated places.
4. Making the ailerons was the easy part. Just cut the flute along the span of the wing on one side only. Make sure u cut the whole strip between the 2 vertical members of the flute. The ailerons are part of the wing so no sticking and few chances of malfunction.
5. I cut the PC sheet using a regular cutter (The one u get in stationary shops, which has snap off blades). Though it took some strength in the begining, but once I found the right technique it was very easy. Just take care that the blade is flush with a side wall on the flute and it cuts like butter. The same thing works with coro. I did not use any file for cuting. I only needed a file to taper the edges, at places where I had to cut against the flutes and that took some time.
As for paint  (  ) none was used. I designed the decals and a friend of mine who has exprience in cuting radium sheets helped me cut them out. Though for the next plane I plan to use vinyl for the decals. Its much cheaper.

Will take some photograps of the tools and material that I used and will post them ASAP.
Hope this was helpful.
Happy building
Doc

Ismail, We had set dual rates for all control surfaces, but when Harveer sir gave me the Tx to fly the plane the throws were set to low and it did level out a wee bit when I tried to pull the elevator but because the throws were small and the distance was not too much I guess it crashed. By the time harveer sir could pull the Tx from me, flick the switch to full throws and level the plane it was on the ground. Though it came in in a nose dive, I guess the plane must have straightened out a bit cos the engine mount broke and the landing gear got twisted. The impact was the belly. The battery came out from the zip ties and 1 of the 2 zip ties on the reciever broke.
What changes can I do for next time?
Flew 3 sorties today. One solo came back in one piece 
Waiting for ur suggestions
Doc

thnks a lot doc...

radium stickers is a good idea n has come out real well... do let me know how to do it.

cheers

Now, I see it. I would suggest you to use exponential than using dual rates. Expo could be helpful in times like these. Make the throws softer around the center stick and more larger around the stick end points.

One more thing I noticed in the video is that you seem to start the engine in the clockwise direction. Most engines run counter-clockwise. Whats the engine you are using?

-Ismail

Quote from: izmile on May 17, 2010, 01:00:19 AM
One more thing I noticed in the video is that you seem to start the engine in the clockwise direction. Most engines run counter-clockwise. Whats the engine you are using?

Most people on our field start engines this way now.  They call it "recoil start".  I think it was from our master builder Mike that people picked it up.  At least I don't remember seeing it before Mike became active on our field.

Basically you get added help when the prop recoils when trying to rotate the other way. It is almost like a spring action, where the prop gets loaded during the flick in the opposite direction, but as the finger (or chicken stick) slips away, the prop rotates in the right direction at much higher rate than if we had flicked in the right direction in the first place. Sometimes the engine does start and rotate in the other direction, then just bring the throttle close to quitting, and take it up when the engine stutters, and it changes direction ! Rarely you have to stop the engine and try again.

Hmm.. got to try that out.  I had previous experience on super tiger engines running backwards (sometimes) even if you flip it the right way. I found that is due to larger intake hole in the crank shaft. I did not have this happen in any of my OS engines.

If the carb/crankshaft is timed properly, flipping backwards will make the carburetor cycle the other way - Carb will spit fuel instead of sucking in. If the engine runs backwards continuously then for sure the fuel/air mix is reaching the cylinder through some other route.

Further, its more dangerous to flip the prop in the opposite direction. The engine is intended to run in the other direction and you will get a nasty kickback. (Well, its not a kickback.. its trying to spin in the right direction) I am not sure what is the benefit of starting the engine this way.

Quote from: izmile on May 17, 2010, 02:32:20 AM
Further, its more dangerous to flip the prop in the opposite direction. The engine is intended to run in the other direction and you will get a nasty kickback. (Well, its not a kickback.. its trying to spin in the right direction) I am not sure what is the benefit of starting the engine this way.

That exactly is the benefit   The "nasty kickback" acts as a boost in the right direction. Engines flick start much easier this way.  Some stubborn ones (at least for the first start of the day), do end up needing a starter.

BTW, this is for glow engines; for gas ones, it is always flicked in the right direction.

I am not sure about the "carb spitting fuel out" part, got to think that one through.  I do see always that the power and overall feel of the engine was fairly different when they were running in the opposite direction.

NOT sure if anybody observed... in the video i saw the person choking the carb with the glow booster on...  hats off to you !!! i must say, either he is new or not aware of the consequences. i have personally seen disasters like this... one person even had a split finger as the engine started suddenly while choking the carb with the glow booster on...

PLEASE NEVER EVER DO THAT !!!

I would never suggest any person getting casual with the engine with the booster on...
----Never choke the engine while the booster is on.----
----Keep your other hand clear from the prop while flicking the engine.----
----Never lean over the engine while starting. If the prop is loose, it may fly off. ----
----Never let anyone stand in the line of the prop, it may be loose and spin off.----
----If you are wearing  neck strap, ensure it does not fall in the line of the engine while starting.----

Please respect your NITRO ENGINES. They can be real pain if not treated properly.

There are some protocols and discipline to be observed while starting engines.

Wish everyone a safe start, fun flying and a happy landing. !!!

Point well taken Saurabh. That novice was me.
Will remember your caution and take care the next time.
Thanks for you advise.
Doc

Quote from: anwar on May 17, 2010, 04:20:33 AM
That exactly is the benefit   The "nasty kickback" acts as a boost in the right direction. Engines flick start much easier this way.  Some stubborn ones (at least for the first start of the day), do end up needing a starter.

I hope you use a stick to flip the prop. You wouldn't know when the engine would kickback. Better to be safe.

Haven't used one till date But reading about the probs I think I'll start using one. To tell u the truth, infact no one on our field uses a chicken stick.

Quote from: izmile on May 17, 2010, 04:49:59 PM
I hope you use a stick to flip the prop. You wouldn't know when the engine would kickback. Better to be safe.

Actually the engine kicks back every single time !  That is the principle that seems to be behind this method of starting. 

Yes, pretty much everyone on the field has a chicken stick, and use them regularly.  One person uses some thick gloves (I think it is made of leather, at least partly).  Only some 50cc and higher guys seems to use their hands directly to flick start, I guess they trust their engines well over long periods of use (they tend to start on the first flick itself most of the time).

Quote from: flying doc on May 17, 2010, 04:53:53 PM
Haven't used one till date But reading about the probs I think I'll start using one. To tell u the truth, infact no one on our field uses a chicken stick.

I did not use chicken stick until I got a nasty deep cut. Learnt the lesson the hard way. You can have a fancy rubber gripped chicken stick or just a small peice of PVC pipe will do the job. Its fine as long as your fingers are away from the prop.

Someone on our field uses a wooden rod (cylindrical all the way), something like a "chappati roller" cut in half   Looks like as long as it is not your fingers directly on the prop, pretty much anything works.

Then chapati roller it is  . Done.