Funjet ultra 6s 300kmph+ build and maiden flight.

Started by dhruvafreak, December 10, 2015, 03:18:45 PM

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dhruvafreak

Hi guys, posting the funjet build thread after a long time of inactivity.
Unfortunately i lost my cell phone with all the build pics on it but still will be posting whatever is left over on my laptop.

For this build i will be using-
- CA 793
- 5 min Epoxy
- SK3 1900kv EDF Inrunner Motor
- 200A HK SS series ESC
- Castel 10A Bec
- Turnigy tgy-90s Mg servos x2
- 6x6 Gemfan (Graupner cam speed 7x7 upgrade later)
- 1300mah 45C 6s x2 Lipo

NOTE :
-For the sk3 motor, the prop bore diameter and to be increased to 6mm (Except cam prop).
-Center the servos before installation.



Build is straight forward.





Servo Mounting:
The mounting gap needs to be incresed for these 90s servos and can be done easily using surgical knife.
Since it's a tight fit for the servos, i have only used .2-.3mm double sided tape for installation.




Extra Intake :
During the static thrust and electronics check up procedure i found that the esc and could touch 70C easily so thought
of adding extra air intake vent for cooler system.
Intake is just above the Esc mounting location which is just under the carbon rod.






Motor Mount:
Used the stock motor mount but extra 2 holes required for the motor mounting which is done using dremel.

More:
-The full kit was sanded and will be glassed in later stages along with custom vinyls.
-The gap between the carbon rod was filled with epoxy and all the joints were assembled using CA793.
-Couldn't get a metal Motor mount so shall be running the stock one and later CNC mount will be made.
-The front canopy hatch has to be sanded from underneath .7cm for battery placement. CG is proper with both batteries pushed in front.

Agile 7.2                 (Kde 12s | Yge | Kds Hv | Sk540)
Goblin 700 Carbon  (Kde 12s | Yge | Rjx | Sk540)
Goblin 500 Sports   (Quantum 6s | HW | KST | Sk540)
Gaui X3                   (Scorpion 6s | Castle Bec | Yep | Tgy306hv | SK540)
Multiplex Funjet | Dynam Su26M | Arising Star

--------------  Married With Helicopters!  ----------

For Rc Action Subscribe :
https://www.youtube.com/user/dhruvafreak

dhruvafreak

And now the maiden flight preparation.
I'm using stock vinyl for maiden but will be changed to something more visible in sky.








I was slightly nervous about the takeoff. Worrying about the torque roll and take off throttle.
Did a 100% throttle take off with more then 100 degree torque roll.
Anjan Babu a forum member also my roommate helped me in getting the bird in air and as well in building the aircraft.







Agile 7.2                 (Kde 12s | Yge | Kds Hv | Sk540)
Goblin 700 Carbon  (Kde 12s | Yge | Rjx | Sk540)
Goblin 500 Sports   (Quantum 6s | HW | KST | Sk540)
Gaui X3                   (Scorpion 6s | Castle Bec | Yep | Tgy306hv | SK540)
Multiplex Funjet | Dynam Su26M | Arising Star

--------------  Married With Helicopters!  ----------

For Rc Action Subscribe :
https://www.youtube.com/user/dhruvafreak

dhruvafreak

Agile 7.2                 (Kde 12s | Yge | Kds Hv | Sk540)
Goblin 700 Carbon  (Kde 12s | Yge | Rjx | Sk540)
Goblin 500 Sports   (Quantum 6s | HW | KST | Sk540)
Gaui X3                   (Scorpion 6s | Castle Bec | Yep | Tgy306hv | SK540)
Multiplex Funjet | Dynam Su26M | Arising Star

--------------  Married With Helicopters!  ----------

For Rc Action Subscribe :
https://www.youtube.com/user/dhruvafreak

satz flying

Its crazy . . . Couldn't find your plane in the sky
Trust yourself

K K Iyer


xantos

Dhruva
Try launching with 1/2 throttle open and gradually increase to full and you won't have to deal with so much torque coming in suddenly.
Or throw out the electric  and Switch to turbine - no torque Only thrust !
Then you'll be looking at a real 300KMPH
;D

dhruvafreak

@Satz_flying yes agreed ! I did the second flight and recorded on 4K. 2nd video visibility is amazing if seen on 4K :D

@K K Iyer Thanks sir. That was the most luckiest pull for me :D

@Xantos sir,  Yes sir i did the same on the second flight since i could predict the aircraft. Did the second flight with more alpha chuck and 40% throttle. Still was a rocket. Turbine for sure. Maybe in next few years.

I couldn't give more then 50% on the maiden but on the second flight i did give 100% for few seconds  This one is insane but I get continous turque roll as i increase the throttle. I assume i have to crosscheck the left or right thrust angle.

www.youtu.be/hUgW6V9q3T4
Agile 7.2                 (Kde 12s | Yge | Kds Hv | Sk540)
Goblin 700 Carbon  (Kde 12s | Yge | Rjx | Sk540)
Goblin 500 Sports   (Quantum 6s | HW | KST | Sk540)
Gaui X3                   (Scorpion 6s | Castle Bec | Yep | Tgy306hv | SK540)
Multiplex Funjet | Dynam Su26M | Arising Star

--------------  Married With Helicopters!  ----------

For Rc Action Subscribe :
https://www.youtube.com/user/dhruvafreak

K K Iyer

Fantastic! Even without fan.
Looks much better without black tape on nose, and with orange on wing upper.
Wait till Gusty sir sees this video...
We have an edf like this here, but it doesn't seem so fast...

rastsaurabh

Nice Very Nice ....
Almost like bullet...

What is the orange covering you have done... is it monokote? or vinyl?

dhruvafreak

@Kk Iyer - Yes sir and the bottom side covered with bright green. Not shown in the picture but in video can be seen.

@rastsaurabh - Thank you :) . Its vinyl.
Agile 7.2                 (Kde 12s | Yge | Kds Hv | Sk540)
Goblin 700 Carbon  (Kde 12s | Yge | Rjx | Sk540)
Goblin 500 Sports   (Quantum 6s | HW | KST | Sk540)
Gaui X3                   (Scorpion 6s | Castle Bec | Yep | Tgy306hv | SK540)
Multiplex Funjet | Dynam Su26M | Arising Star

--------------  Married With Helicopters!  ----------

For Rc Action Subscribe :
https://www.youtube.com/user/dhruvafreak

shobhit17

#10
Well saw your launch of the model.... guess the roll to the left is not just because of the torque but also the way you are throwing it.  The way you are holding leaves very little place for a firm hold to throw the model correctly i.e wit wings level.  Loot at my video of launching a Vortex RC Speedster.  The model is overpowered and flies like a rocket.  Yes all take offs will be at high power settings throttle because this is how you go up and away from the ground in an instant.  My advice an a seasoned aviator is never take off with less power and as far as possible use 100%.  There are more advantages of using 100% power than the disadvantages.
Well I been into aeromodelling since I was in School....  and then been in the air for over 30 years.  Now looking to be back into aeromodelling full time...

AnjanBabu

Shobit17, the cause for the left roll is purely anti-torque generated by the motor. I know that because, I couldn't resist the torque roll holding the plane with both my hands while shooting up from just 0-10% throttle. 

I partially agree with what you have to say about the way I was holding the plane, then again, that's where and how you should hold a narrow rounded fuse weighing in at 1.3kg with 50/50 weight distribution. ;D

Completely disagree with your claim that all take-offs should be at full throttle, didn't expect that from a seasoned aviator. Technically, planes go up and away at minimum take-off speeds.

Maybe not much of a rocket, but that thing flew like a blazing rock out from space. ;)
Mechatronics engineer . Hopeless realist

anjanbabu.wordpress.com

dhruvafreak

Thanks for the suggestion Shobhit sir, however i wouldn't agree on 100% throttle for takeoff.

Since I'm Pursuing my Aerospace Engineering and i have come across Adverse Yaw condition which acts because of Spiral propwash generated by single engine prop planes.
It causes yaw when they are flown at high power and low speed (takeoff and climbout, for example.) The prop doesn't blow the air straight back, but gives it a bit of a twirl which causes yaw.

And difference in profile drag between the upward and downward deflected ailerons which in case of countering the torque is applied , the difference in lift and thus induced drag between left and right wings which tends to yaw the aircraft in the opposite direction of a roll.

So because of these two reasons the aircraft might just yaw severely under full power and while countering the torque.

I have learned this very hard way while building and testing a Model(.35kg) made to carry payload (1.5kg). I have tried full throttle and have seen the yaw conditions i stated and crashed.
Agile 7.2                 (Kde 12s | Yge | Kds Hv | Sk540)
Goblin 700 Carbon  (Kde 12s | Yge | Rjx | Sk540)
Goblin 500 Sports   (Quantum 6s | HW | KST | Sk540)
Gaui X3                   (Scorpion 6s | Castle Bec | Yep | Tgy306hv | SK540)
Multiplex Funjet | Dynam Su26M | Arising Star

--------------  Married With Helicopters!  ----------

For Rc Action Subscribe :
https://www.youtube.com/user/dhruvafreak

shobhit17

#13
Dear Mr Anjan and Dhruva you may be experts in the fields on which you are commenting.... I am no one to force my advice on you.  Please go ahead and do what you been doing..  

Talking of adverse alieron you... the situation when the adverse alieron yaw develops in an aircraft is absolutely different and not what you are talking off.... You may like to read the highlighted portion in the Lift Coefficient heading.  Thats why it becomes more improtant that your model exits the slow speed regime at the earliest a


For your information please go to wikipedia for adverse alieron you and will find this..........:

Minimizing the adverse yaw
There are a number of aircraft design characteristics which can be used to reduce adverse yaw to ease the pilot workload:

Aileron to rudder mixing
As intended, the rudder is the most powerful and efficient means of managing yaw but mechanically coupling it to the ailerons is impractical. Electronic coupling is commonplace in fly-by-wire aircraft.

Lift coefficient
As the tilting of the left/right lift vectors is the major cause to adverse yaw, an important parameter is the magnitude of these lift vectors, or the aircraft's lift coefficient to be more specific. Flight at low lift coefficient (or high speed compared to minimum speed) produces less adverse yaw.[1]:365

Yaw stability
A strong directional stability is the first way to reduce adverse yaw.[6] This is influenced by the vertical tail moment (area and lever arm about gravity center).

Differential aileron deflection

Illustration of a Differential aileron
The geometry of most aileron linkages can be configured so as to bias the travel further upward than downward. By excessively deflecting the upward aileron, profile drag is increased rather than reduced and separation drag further aids in producing drag on the inside wing, producing a yaw force in the direction of the turn. Though not as efficient as rudder mixing, aileron differential is very easy to implement on almost any airplane and offers the significant advantage of reducing the tendency for the wing to stall at the tip first by limiting the downward aileron deflection and its associated effective increase in angle of attack.

Most airplanes use this method of adverse yaw mitigation due to the simple implementation and safety benefits.
Well I been into aeromodelling since I was in School....  and then been in the air for over 30 years.  Now looking to be back into aeromodelling full time...

AnjanBabu

Please check the last three take off pics posted in Reply #1, they're self-explainitary. I don't understand how you could get torque rolls wrong.
BTW, that plane torque rolls in mid air at full throttle and 50% throttle is still a bit much to take off I guess.
Mechatronics engineer . Hopeless realist

anjanbabu.wordpress.com

shobhit17

#15
god helps you dear Ajnan.... go and do what you feel like....
Well I been into aeromodelling since I was in School....  and then been in the air for over 30 years.  Now looking to be back into aeromodelling full time...

AnjanBabu

Mechatronics engineer . Hopeless realist

anjanbabu.wordpress.com

dhruvafreak

I don't know why you are offended SIR but i just shared knowledge what i was facing.  :headscratch:

I have been to the wiki page about idk how many times.

And You didn't see yaw because its a pusher model and the wash is not hitting the vertical fins and its 50% throttle . I can do a vertical takeoff with 40%.  :thumbsup:

The model has thrust to wieght ratio is greater then 1 so its practically impossible to hold during hand launch.

Keeping 100% throttle , I'll definitely have max torque during launch since there's no airflow to counter the torque.  :hatsoff:

Agile 7.2                 (Kde 12s | Yge | Kds Hv | Sk540)
Goblin 700 Carbon  (Kde 12s | Yge | Rjx | Sk540)
Goblin 500 Sports   (Quantum 6s | HW | KST | Sk540)
Gaui X3                   (Scorpion 6s | Castle Bec | Yep | Tgy306hv | SK540)
Multiplex Funjet | Dynam Su26M | Arising Star

--------------  Married With Helicopters!  ----------

For Rc Action Subscribe :
https://www.youtube.com/user/dhruvafreak

bmblb

......Guys.....this is a killer  >:D

would love to see it being flown by you guys  :thumbsup:
"The Flight Of The Bumblebee"

dhruvafreak

@Bmblb thank you.
Would definitely get to hoskote to fly it. :hatsoff:
Agile 7.2                 (Kde 12s | Yge | Kds Hv | Sk540)
Goblin 700 Carbon  (Kde 12s | Yge | Rjx | Sk540)
Goblin 500 Sports   (Quantum 6s | HW | KST | Sk540)
Gaui X3                   (Scorpion 6s | Castle Bec | Yep | Tgy306hv | SK540)
Multiplex Funjet | Dynam Su26M | Arising Star

--------------  Married With Helicopters!  ----------

For Rc Action Subscribe :
https://www.youtube.com/user/dhruvafreak

shobhit17

#20
well.... I never said that you can not do a takeoff with less than 100% power.  You do not need an airflow to counter it.... you got those two big vertical stabs on your wing to counter any unwarranted instability........... even my model can take off with 50% throttle and it jumps off my hand at full throttle.... it does not mean that 50% throttle is enough for takeoff.....  

Anyway... as i said earlier... I was talking of what is done best to maintain a good quick take off and an early exit from dangerous flight regimes....... if you can manage it at low throttle go ahead and do it... but next time do not blame me for a crash due to compounded effect of torque roll and a tip stall..... and maybe many more thinks like winds compounding the problems on your take off.....
Well I been into aeromodelling since I was in School....  and then been in the air for over 30 years.  Now looking to be back into aeromodelling full time...

rastsaurabh

Guys my 2 cents.... ( with simple logics )

Shobit is correct for 100% throttle for LAND takeoffs and is reasonable for obvious reasons.

where as in hand launch scenarios ( which are nearly zero in real world) slow increase of throttle looks better than 100% throttle at an instant.

I may be wrong but as per my exp so far this is what i think stand reasonable.

regds
saurabh

aniket210696

That looks insane Dhruva... i dont know how you manage to fly that.... or infact see it xD  Cant wait for you to give it a "Beach Run" if you get the gist >:)

PS: is it just me or this actually one of the most informative threads in a while? :D
.

Shannon

Sir i get ur point bout using 100% throttle ...but as you u see sir its hand launch there is no ground roll the aircraft is already in the air during launch so the matter of escaping  is negligible and the thrust to weight ratio is really high ...another thing sir is the torque generated on the motor on this model is  high...if he happens to use 100% throttle on this model during t/o  the aircraft will just roll and dive into the ground , very little airflow over the wings wont be  able to compensate for the amount of torque generated ...even if full deflection is applied ...correcting an aircraft in such a situation would be disastrous..to avoid the intial surge of torque and also to generate enough airflow to compensate the increasing torque ...keeping the throttle to at minimum for intial climb performance and gradually increasing the throttle to avoid the surge of torquue is a better approach to 100% ...plus this model has wing fence thus taking care of the other problems associated with airflow AND STALLS ...
Wings are for wimps  :)-Mikado Logo/"OXY3  "/Scorpion Motors/Savox/JR PROPO/Spinblades/EDGE BLADES/KDE Direct/YEP/YGE/RJX/ GENS ACE Bavarian Demon-

shobhit17

#24
Saurabh if i may correct here.... a takeoff is always a takeoff.... I am not saying maintain 100%...but it will be desirable to maintain a relatively a high throttle setting. I am saying have a throttle setting to get out of the danger regime (close to ground and in the air say.... 25 mtrs for models)... thereafter you may use the throttle as required....  Shannon your contention of gradually increasing throttle is wrong for many reasons....... I can explain that some other time, if you still need an explanation of how and why of aerodynamics, call me and I will clear the doubts....
Anyway... I am leaving this thread....
best Wishes
Well I been into aeromodelling since I was in School....  and then been in the air for over 30 years.  Now looking to be back into aeromodelling full time...