Re: SIG Wonder build thread - ASP12 vs COX TD09

[1/2A Nut]

Sig Wonder. Cox Conquest .15, slightly modified, 10%

[balogh]

Thanks Kris and Brad (especially for the greenie)

You are right a 2 bladed prop is safer but I only have one 7*4 on the Cosmic Wind so I only used the 3 bladed to check the overall weight.

I will break in the TD09 maybe tomorrow so stay tuned.

[MauricioB]

It is practically ready to fly. Empty weight without fuel is 550 grams i.e. about 19 oz.





Total wing area is 338 sq.inch according to SIG...maybe too light???

Excellent friend! .... you have built it quickly !!, you see it very well ... I'm looking forward to a flight video !!

[getback]

The plane looks Great !! i see its ailerons only for turns , i think she going to bee fast !! Looking forward to the TD.09 break in .

[fredvon4]

Wow..Oct 15th start...very good looking and cool airplane done in 7 days

I like it

[balogh]

Thank you all. This is an easy build model with only a few main parts, basic symmetric wind with no dihedral..

The most difficult for me - like always - is not to destroy the nice look the balsa skeleton had when adding Oracover

[balogh]

Thanks Kris and Brad (especially for the greenie)

You are right a 2 bladed prop is safer but I only have one 7*4 on the Cosmic Wind so I only used the 3 bladed to check the overall weight.

I will break in the TD09 maybe tomorrow so stay tuned.

I finally started up the new TD09 (the one with the booster flutes machined by the previous owner in the bypass ports.)

The engine started up very easily with a few hand-flips, no electric starter was needed.

Because I pulled a 14x1mm O-ring on the cylinder neck where it sits in the muffler, the engine also runs very clean with no castor flowing down the engine and accumulating in the cowl...

The muffler and the R/C carb have some impact on the output but I guess it still will be more than sufficient for the SIG Wonder.

After a few 3-minutes rich runs  to allow a smooth run-in, I peaked it and  tached 15010 rpm with a 7x4 black Graupner prop, muffler, R/c carb and spinner, the fuel is 20/20/60 home blend. I expect this rpm to improve a bit after some runtime.

The R/C carb works very well for a COX R/c carb: stable idle around 8000 rpm  with the high compression stock COX head,(idle yet to be refined) and excellent response to the throttle arm, sending the speed up to 15k instantly.

As seen, I pulled silicone cuffs on the fuel nipple and the Needle Valve stem (that has a small o-ring but it does not keep the valve in a fixed position after some time of ageing) both to secure leak-free run.

I could not make a vid as yet, maybe i will ask my wife to be my camerawoman tomorrow. Unfortunately the weather turned very lousy here with 100km/h wing gusts and rain so I still need to wait before I can maiden the Wonder...

This is the setup in the nose:



(The tube pointing to the backplate is the filling line...no tank pressurization, I use the good ole rubber balloon tank)

[roddie]

Thank you all. This is an easy build model with only a few main  parts, basic symmetric wind with no dihedral..

The most difficult for me - like always - is not to destroy the nice look the balsa skeleton had when adding Oracover

I too am blown-away at the speed in which you built this model Andras! Did you stop to eat? The covering and trim looks really nice.. and you shouldn't undersell yourself in your abilities there.

What is the fuel-capacity of the balloon that you're using? My largest balloons are 9"/22.8cm (inflated-size) and would appear to hold approx. 1oz. of fuel +/- a cc or two before they would begin to stretch. I've yet to "run" a balloon tank.. but I have several bags of assorted-size/shape balloons on hand, for when that time comes.

Regarding your fill-tube running through the center of the firewall; do you evacuate air.. then inject fuel.. then "cap" that line? I'm still grappling with the method. I assume that the needle must be closed for air-evacuation.. but I'm thinking that there must be ample volume in a syringe for drawing-out the air.. followed by filling to the desired-capacity of fuel. Do you use a large-capacity syringe for this? Local to me, is an agricultural hardware store that "may" have syringes which are of a larger-capacity than one would expect to find at a drugstore.. for the oral-injection of medications for horses/cattle etc. I'm wondering if obtaining one might be a step in the right direction?

I hope that your weather clears soon.. and your "camera-woman" is on "stand-by status"...   I'm sure that you're anxious to fly this model.. after building it in "record-time"!    

[balogh]

Thanks Roddie...I really built it quick, I remember one evening I came home from work and continued building the Wonder till 2 am the next morning. I also suffer from allergy when I use CA glue, and coughing and sneezing just added to the romantic efforts the result is not really bad but is a world apart from the quality you guys on CEF cover your birds..just look at the finish of e.g. Mauricio's planes...

As to the balloon tank the process is exactly as you described.


The baloon I found recently in a DIY shop holds at least 2 oz fuel - my Cosmic Wind with another TD09 in its nose flies around 9-10 minutes on such a supply -  and need not be pre-evacuated before I start filling it with a 2 oz syringe I bought in a vet's supply shop...after some  half of the fuel in the syringe has been pumped into the balloon, you hold the plane with its nose up - actually you keep holding it with its nose up during the entire filling so that you do not flood the engine -  and pull on the piston of the syringe, drawing back the air through the fill line, captured in the high point of the balloon..when the air is sucked you continue pumping the rest of the fuel then plug the fill line. The fill line just passes through the rubber stopper I put in the throat of the balloon and does not extend into the balloon so that when you hold the plane vertical nose up, you can evacuate air from the balloon high point through it.

I will hopefully maiden it but chances are thin these days with sh@@@@@tty weather persisting here.

[MauricioB]

Thanks Roddie...I really built it quick, I remember one evening I came home from work and continued building the Wonder till 2 am the next morning. I also suffer from allergy when I use CA glue, and coughing and sneezing just added to the romantic efforts the result is not really bad but is a world apart from the quality you guys on CEF cover your birds..just look at the finish of e.g. Mauricio's planes...

As to the balloon tank the process is exactly as you described.


The baloon I found recently in a DIY shop  holds at least 2 oz fuel - my Cosmic Wind with another TD09 in its nose flies around 9-10 minutes on such a supply -  and need not be pre-evacuated before I start filling it with a 2 oz syringe I bought in a vet's supply shop...after some  half of the fuel in the syringe has been pumped into the balloon, you hold the plane with its nose up - actually you keep holding it with its nose up during the entire filling so that you do not flood the engine -  and pull on the piston of the syringe, drawing back the air through the fill line, captured in the high point of the balloon..when the air is sucked you continue pumping the rest of the fuel then plug the fill line. The fill line just passes through the rubber stopper I put in the throat of the balloon and does not extend into the balloon so that when you hold the plane vertical nose up, you can evacuate air from the balloon high point through it.

I will hopefully maiden it but chances are thin these days with sh@@@@@tty weather persisting here.

András !, congratulations, it has been very good! ...
Now in the sweet wait .... I say, the one that comes good weather to try and enjoy in flight !!
Here there is also a storm and it rains, Sunday morning I thought about going to fly, but I think the rain will not leave me ... patience ... it is a good tool in these cases!
I must sincerely thank you for your words of recognition about my work - airplane models, thank you for your concept!

[roddie]

Thanks Roddie...I really built it quick, I remember one evening I came home from work and continued building the Wonder till 2 am the next morning. I also suffer from allergy when I use CA glue, and coughing and sneezing just added to the romantic efforts the result is not really bad but is a world apart from the quality you guys on CEF cover your birds..just look at the finish of e.g. Mauricio's planes...

As to the balloon tank the process is exactly as you described.


The baloon I found recently in a DIY shop  holds at least 2 oz fuel - my Cosmic Wind with another TD09 in its nose flies around 9-10 minutes on such a supply -  and need not be pre-evacuated before I start filling it with a 2 oz syringe I bought in a vet's supply shop...after some  half of the fuel in the syringe has been pumped into the balloon, you hold the plane with its nose up - actually you keep holding it with its nose up during the entire filling so that you do not flood the engine -  and pull on the piston of the syringe, drawing back the air through the fill line, captured in the high point of the balloon..when the air is sucked you continue pumping the rest of the fuel then plug the fill line. The fill line just passes through the rubber stopper I put in the throat of the balloon and does not extend into the balloon so that when you hold the plane vertical nose up, you can evacuate air from the balloon high point through it.

I will hopefully maiden it but chances are thin these days with sh@@@@@tty weather persisting here.

Thank you for the explanation of your set-up and fueling-method Andras. I now have a better understanding of the system.

[balogh]

Nasty weather finally allowed me to maiden the Wonder:



Despite my worries that the TD09 will not be strong, and heavy enough, the maiden was a success: The engine is, albeit the smallest recommended for this plane, pulls it with excellent authority, and the center of gravity is just at the right position, at the wing spars, because the engine was placed relatively far ahead on the mounts..

Apart from the hectic climbs due to the excessive elevator throws that I will still have to tame, the plane flies beautifully, very well maneuverable with tight turns, wing-overs, spirals etc.

Worth to mention is the excellent gliding capability that is shown at the end of the vid when I landed with dead-stick, against a strong headwind.

I had pretty strong winds and chilly weather, so after a second flight that just re-confirmed the plane's qualities, I called it a day for today.

[getback]

Good Maiden Andres , see is a little squirrely , what are your elve. rates on ? Is a good floater , like the landing you're going to have a bunch of fun with that plane for sure !! Thank You for the Video ~

[balogh]

Thanks Eric, I like this "squirrelly" adjective

Indeed it jumps like a chipmunk and the elevator throw which maybe near 3/4 inch at the tip needs readjustment.

[1/2A Nut]

Maximum review to help best I can:

Floats in as expected, pitch sensitive with such a small elevator takes a moment to command the wing.

It would start diving under power never held level flight, the elevator is small so when it catches
control of the air flow the wing pitches up a bit abruptly.

Is there down thrust in the engine?
Glided a hair tail heavy with the engine off a hair bit mind you into the wind.
S turns on landing to bleed off learned sink rate or ailerons still a bit touchy, wind was pushing it to the left.

Must of been a second flight vid unless the ailerons where tame already enough for you to roll
it so early without trying to trim the elevator / ailerons first.

Engine sagged on launch and twice more.
I would use muffler pressure tap and hard tank for steady top end rpm during abrupt maneuvers.

Spinner and prop need to be vibration free to reduce wear on the aluminum crank case.
Yellow spinner robs rpm adds stress to the ball socket as air flow is hitting it constantly.
Unless I have a engine with a bronze crank case sleeve spinners that size are never used.

What prop, amount of nitro, air temp, wind speed?(Based on trees and mic sub 9mph / 14.4kph)

Beyond that I am happy for you, and hope you enjoy many flights with your new project.
Thank you for making the effort to share your project with us I look forward to your next
video once your have everything sorted out and use to flying the plane how you like to best.

A greenie for you  


 

[balogh]

Thanks Brad for the suggestions and the greenie. The engine sags only when I hand launch too quick: the ballon tank slightly expands under the inertia of the fuel inside it and it pulls the fuel back from the carb. When launched slightly slower the engine speed does not drop.

The prop is 6x4 and the fuel is home blended 20/20/60.

I did not measure wind speeds but had nasty gusts through the flight.

The engine has downward thrust. The ailerons are as they were set before the maiden..I do those rolls only at safe heights.. I must admit I am more of an instinct flyer than a scientific one.

I like the yellow spinner and it is well balanced ..I feel no engine vibration.
It may rob some rpm but helps the air pass the engine bay and thus may add to the efficiency of traction??

[1/2A Nut]

- If the prop /spinner is well balanced it blankets part of the prop allowing some rpm unloading
- Yes agreed aids in aerodynamics
- Engine sagged in the air when you pulled up hard at 2:20 mins few others mild ones.
- Pass at 1:22 min in vid 22,046 rpm / possible  83 mph / 133 kph per thrust calc.
- Static 17,038 / 16.93oz thrust / 65 mph pitch speed / .184hp / 137W

[balogh]

Here is the 2nd flight today. It starts with a suicidal dive - yes the engine sagged again - that I managed to continue with a rise. The runs are more level here and I added more spins too. The landing was not so glorious though, thanks to the winds getting even stronger...I did not want to share this one because of the troubled take-off and lending, but because the mid-air behaviour of the plane was much nicer than during the maiden so I changed my mind. Her you can sometimes hear how the wind whistled into the camera.

[roddie]

Congratulations on a successful maiden of your Sig "Wonder" Andras!!! I was there with you in "spirit" while watching the vid!! There's no doubt that the Tee Dee engine is up to the task!

[balogh]

Thanks Roddie..in fact the major part of my obsession to flying model airplanes is clearly related to COX engines..although I have a few other makes too but I have never really thought of flying anything other than COX..let alone electric planes.

I wish you also find a good and tough use for your 09.

[1/2A Nut]

Yes the winds started to pick up on this flight did you add a click or two of up trim?

The engine sag is bad at the worst time during launch woo scary
The TD .09 is a thirsty engine, I have dealt with the sagging issue too when
using a exhaust throttle.

Set at full throttle and let it pull away from the hand helps to keep the fuel flow moving
into the NV body. Any tossing forward has to be very smooth rather than abrupt.

No issues with a pressure tap on the muffler screams right out of the hand.

[MauricioB]

Here is the 2nd flight today. It starts with a suicidal dive - yes the engine sagged again - that I managed to continue with a rise. The runs are more level here and I added more spins too. The landing was not so glorious though, thanks to the winds getting even stronger...I did not want to share this one because of the troubled take-off and lending, but because the mid-air behaviour of the plane was much nicer than during the maiden so I changed my mind. Her you can sometimes hear how the wind whistled into the camera.

Dear András, what a joy it is to see how good that model is, first of all my sincere congratulations and the joy that you feel inside you, as well as most of us that we would like to be able to share those beautiful moments in person, so I join Roddie's comment, there are many of us with you enjoying and sharing !.
Regarding the flight of the model, from my point of view, placing some exponential in the commands can help you to have a very neat model in the flight without frights and logically You will be adjusting flight after flight.
The engine carries it of marvels, creates me it is appreciated perfectly, I am surprised that even with a balloon that exerts pressure on the fuel, that pressure is not enough to compensate the recoil of the fuel at the time of launch. I agree with Brad, the line of Tee Dee engines and some with flaper valve, it is convenient to throw them gently and in that way do not (tell - decays) the engine.
I send you a big hug from here and I hope more flights and more shared videos!

[balogh]

Hi Mauricio, it is so nice to know that you and others share with me the joy of creating again something airworthy with a COX engine in its nose.

I will follow your and Brad's advice. The Futaba radio I have allows the setting of the servo speed, it has similar effect as the exponential that I could set on my previous radios. The elevator speed - and throw - will both be set to lower values.

The balloon tank is a different thing: what is its advantage during normal flights is its disadvantage in transient conditions like acceleration when e.g. hand-launching. Remember that it is not pressurized by overfilling it with fuel like in the C/L planes, otherwise it would have a different supply rate at the beginning and end of the flight. But having soft walls it will expand under the inertia of fuel mass when accelerating.

The best would be to have a tiny non-return valve in the fuel line, preventing backflow of fuel...but that would also add to the fuel line resistance a bit and thus impair the engine suction.

Alternatively I may think of a pressurized tank with pressure taken from the muffler.

I will think of the options and let you all know if I arrived at a convenient and safe solution.

Thank you again for your reassuring words.

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