RC India
Welcome Guest, please login or register.
 
Pages: 1 2 [All]   Go Down
0 Members and 1 Guest are viewing this topic. Topic Tools Topic Tools 
Read
« on: September 08, 2010, 10:34:46 PM »
santhosh
Heli Lover
Forum Hero
*****

Reputation Power: 7 
santhosh has no influence.
Offline Offline

City: thrissur
State: Kerala
RC Skills: Beginner
Posts: 507
Join Date: Mar, 2009




test flew the catalina yesterday,but cant able to take off  from the water.as you can see in the video the plane is always turning to the left even at minimum throttle.is there anything to be corrected with the lateral balance?suggestions from all are welcome








Logged
 

Read
« Reply #1 on: September 08, 2010, 11:09:43 PM »
ujjwaana
Plane Lover
Forum Hero

*****

Reputation Power: 28 
ujjwaana barely matters.ujjwaana barely matters.
Offline Offline

City: Bangalore
State: Karnataka
RC Skills: Intermediate
Posts: 2384
Join Date: Oct, 2009



The biggest issue with twin engine/Motor design is to maintain Exactly equal thrust on both the motors. I feel you starboard (right) motor is somehow producing slightly more thrust, maybe due to high RPM or slight difference in Prop dimension. Even slight offset in the thrust angle can cause similar issue.

Use both the Ailerons and Rudder to trim this action, if you can.
Logged

Futaba 8FG Super | HK-450v2 | FA-22 Raptor |AXN Floater-Jet | FunJet | Black Horse Edge 540 | Amp Master 015 | 2.3M Big Brother
 

Read
« Reply #2 on: September 09, 2010, 10:43:58 AM »
bmanoj2
Plane Lover
Forum Veteran

****

Reputation Power: 4 
bmanoj2 has no influence.
Offline Offline

City: Dubai, UAE
State: OUTSIDE INDIA
RC Skills: Advanced
Posts: 372
Join Date: May, 2010



I believe ujjwaana is correct. you can check the rpm of both the motors using the following type Multi-Blade Micro Tachometer.
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=10783
While take off, you can try to keep a little extra Rudder to counter the tendency to turn. But I sujjest you check the rpm first. If you have spare props try mixing changing them until you get a uniform rpm in both motors.
Logged

"Learn from yesterday, live for today, hope for tomorrow."
 

Read
« Reply #3 on: September 09, 2010, 10:46:31 AM »
bmanoj2
Plane Lover
Forum Veteran

****

Reputation Power: 4 
bmanoj2 has no influence.
Offline Offline

City: Dubai, UAE
State: OUTSIDE INDIA
RC Skills: Advanced
Posts: 372
Join Date: May, 2010



Please also check the direction of the WATER RUDDER
Logged

"Learn from yesterday, live for today, hope for tomorrow."
 

Read
« Reply #4 on: September 09, 2010, 10:57:41 AM »
bmanoj2
Plane Lover
Forum Veteran

****

Reputation Power: 4 
bmanoj2 has no influence.
Offline Offline

City: Dubai, UAE
State: OUTSIDE INDIA
RC Skills: Advanced
Posts: 372
Join Date: May, 2010



Please read this link.
http://www.rcgroups.com/forums/showthread.php?t=674400
It says how to correct it, and a good guidance how to takeoff
Logged

"Learn from yesterday, live for today, hope for tomorrow."
 

Read
« Reply #5 on: September 09, 2010, 11:27:58 AM »
santhosh
Heli Lover
Forum Hero
*****

Reputation Power: 7 
santhosh has no influence.
Offline Offline

City: thrissur
State: Kerala
RC Skills: Beginner
Posts: 507
Join Date: Mar, 2009



tnx manoj.lot of information on the rcgroups site,will try to correct the lateral balance first and see how it performs. both the motors and props are the original one comes with the kit

santhosh
Logged
 

Read
« Reply #6 on: September 09, 2010, 11:34:49 AM »
bmanoj2
Plane Lover
Forum Veteran

****

Reputation Power: 4 
bmanoj2 has no influence.
Offline Offline

City: Dubai, UAE
State: OUTSIDE INDIA
RC Skills: Advanced
Posts: 372
Join Date: May, 2010



Then I believe the only problem is with the Lateral Balance and careful rudder correction while takeoff. Smiley
Logged

"Learn from yesterday, live for today, hope for tomorrow."
 

Read
« Reply #7 on: September 09, 2010, 01:10:06 PM »
Ashta
Plane Lover
Forum Hero

*****

Reputation Power: 9 
Ashta has no influence.
Offline Offline

City: Bangalore
State: Karnataka
RC Skills: Intermediate
Posts: 623
Join Date: May, 2009



Dear Santhosh,
Since you have test flown it already, all the diffrentila thrust issues are not likely to be there, unless some thing has changed after the test flight.
in my opinion, after checking things as per manoj and ujjwana, u can try once agin hand launching the model and correcting  few things in flight and triming  it out. After this is done it will be easier to take of from water.
" Evite yanu parappikkunnathu?"

 i had made the Polaris plane and had tried taking of from Water. But this is a single motor pusher and rudder  for water steering.






tnx manoj.lot of information on the rcgroups site,will try to correct the lateral balance first and see how it performs. both the motors and props are the original one comes with the kit

santhosh
« Last Edit: September 09, 2010, 01:15:40 PM by Ashta » Logged

You can't be first because you do not know!
 

Read
« Reply #8 on: September 09, 2010, 01:27:14 PM »
bmanoj2
Plane Lover
Forum Veteran

****

Reputation Power: 4 
bmanoj2 has no influence.
Offline Offline

City: Dubai, UAE
State: OUTSIDE INDIA
RC Skills: Advanced
Posts: 372
Join Date: May, 2010



Santhosh Gi, Correct me if I am wrong, Did you manage to takeoff ??  I only saw the video of aborted takeoff attempts. Huh?
Logged

"Learn from yesterday, live for today, hope for tomorrow."
 

Read
« Reply #9 on: September 09, 2010, 01:31:17 PM »
Ashta
Plane Lover
Forum Hero

*****

Reputation Power: 9 
Ashta has no influence.
Offline Offline

City: Bangalore
State: Karnataka
RC Skills: Intermediate
Posts: 623
Join Date: May, 2009



dear Manoj,
in the first post he said that "test flew the catalina yesterday"
thats why i wrote...




Santhosh Gi, Correct me if I am wrong, Did you manage to takeoff ??  I only saw the video of aborted takeoff attempts. Huh?
Logged

You can't be first because you do not know!
 

Read
« Reply #10 on: September 09, 2010, 01:42:50 PM »
santhosh
Heli Lover
Forum Hero
*****

Reputation Power: 7 
santhosh has no influence.
Offline Offline

City: thrissur
State: Kerala
RC Skills: Beginner
Posts: 507
Join Date: Mar, 2009



sorry for confusing you ashta,manoj. in fact i am not able to fly it yet. tested on the water but its always looping on water. tghe place is near to  my home in irinjalkuda
Logged
 

Read
« Reply #11 on: September 09, 2010, 01:45:05 PM »
bmanoj2
Plane Lover
Forum Veteran

****

Reputation Power: 4 
bmanoj2 has no influence.
Offline Offline

City: Dubai, UAE
State: OUTSIDE INDIA
RC Skills: Advanced
Posts: 372
Join Date: May, 2010



Hi Mr.Ashta, I noticed the following.. " Evite yanu parappikkunnathu?"  Are you from kerala ?? Smiley I never knew that.
Logged

"Learn from yesterday, live for today, hope for tomorrow."
 

Read
« Reply #12 on: September 09, 2010, 01:51:58 PM »
Ashta
Plane Lover
Forum Hero

*****

Reputation Power: 9 
Ashta has no influence.
Offline Offline

City: Bangalore
State: Karnataka
RC Skills: Intermediate
Posts: 623
Join Date: May, 2009



if you have not flown it yet, then my suggestion may be more relevent. pl try hand launching after correcting the issues as stated by Manoj and Ujjwaana


sorry for confusing you ashta,manoj. in fact i am not able to fly it yet. tested on the water but its always looping on water. tghe place is near to  my home in irinjalkuda
Logged

You can't be first because you do not know!
 

Read
« Reply #13 on: October 11, 2010, 09:57:37 PM »
santhosh
Heli Lover
Forum Hero
*****

Reputation Power: 7 
santhosh has no influence.
Offline Offline

City: thrissur
State: Kerala
RC Skills: Beginner
Posts: 507
Join Date: Mar, 2009



yesterday again after adding some weight to correct the lateral balance tried it on our paddy fields,still no luck it's always looping.seems to be the rpm of the left motor is low,watch the video


Logged
 

Read
« Reply #14 on: October 11, 2010, 10:03:46 PM »
santhosh
Heli Lover
Forum Hero
*****

Reputation Power: 7 
santhosh has no influence.
Offline Offline

City: thrissur
State: Kerala
RC Skills: Beginner
Posts: 507
Join Date: Mar, 2009



on the third attempt we forgot to put the rubber fuselage plug  Bang Head Bang Head and here is the final result



Logged
 

Read
« Reply #15 on: October 11, 2010, 10:12:15 PM »
anwar
Administrator
Forum Hero

*****

Reputation Power: 141 
anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!
Offline Offline

City: Doha (Qatar) & Thrissur
State: Kerala
RC Skills: Advanced
Posts: 11619
Join Date: Mar, 2009

RC India - Flying and racing with open minds !



Woah Sad  Up for some major work on it.

It seems like the looping can be handled by applying rudder correction, which I can't see in the video. Remember how I was flying Prakkat's Twinstar with different thrusts on the two motors just by holding a significant amount of rudder to one side ?  The same should work here too !

Another option is to use radio mix programming to adjust the inputs to both the motors, connected on two separate channels.  Prop surgery (trimming one prop slightly, a small bit at a time) may be another less desirable option.

Logged

Hangar : Please see my introduction.
RC India forum and me : About this forum.
 

Read
« Reply #16 on: October 12, 2010, 06:59:31 AM »
santhosh
Heli Lover
Forum Hero
*****

Reputation Power: 7 
santhosh has no influence.
Offline Offline

City: thrissur
State: Kerala
RC Skills: Beginner
Posts: 507
Join Date: Mar, 2009



It seems like the looping can be handled by applying rudder correction, which I can't see in the video.

 i tried with rudder correction ( which is not in the edited video).also the water rudder touches water only wen the plane gains speed
« Last Edit: October 12, 2010, 10:33:19 AM by anwar » Logged
 

Read
« Reply #17 on: May 17, 2011, 12:38:47 AM »
rcpilotacro
Global Moderator
Forum Hero

*****

Reputation Power: 58 
rcpilotacro is on the verge of being accepted.rcpilotacro is on the verge of being accepted.rcpilotacro is on the verge of being accepted.rcpilotacro is on the verge of being accepted.rcpilotacro is on the verge of being accepted.
Offline Offline

City: Delhi
State: Delhi
RC Skills: Advanced
Posts: 5041
Join Date: Nov, 2010

Practice, and only Practice will make you perfect



Santa,
It has nothing to do with the aeroplane, it is do with your control inputs, take off technique for a sea plane is completely different from surface borne  aeroplane, the reason is simple, rudder application will aggravate, water looping tendency, do the following :-

1. Open power very slowly, try not to apply rudder, even if you do, it should be very little.

2. What you should apply the most is opposite aileron, your aim is to pick up the dropped wing. remember as the ailerons are effective dropped wing will come up suddenly (due to sudden release of surface tension of the water) and you may touch the opposite wing,

3. during take off you need to keep wings level, unlike ground, water is a flexible surface and unlike ground aeroplane which has larger track , seaplanes have a smaller track. therefore, direction maintenance on water is by maintaining wings level by moving aileron continuously, sounds funny but true.

4. taxying in water is also mostly with the help of aileron.

Bottom Line

Open power slowly , pick up the dropped wing, when it comes upright, adjust and keep wings level, continue to slowly increase power, DO NOT pull back on the stick, let her fly off the water on her own.AILERON is the key.

Carefully watch this video, you will see hardly any rudder , he aims to get the dropped wing up first, then he looks to take of, somewhere in between you can see he is concentrating on keeping wings level by constantly moving aileron during take off. also in the end see the taxy, is with aileron and very little rudder. for landing you need to come on a power on shallow approach.

http://www.rcgroups.com/forums/showatt.php?attachmentid=1412810
Logged

Gusty's Hangar and Introduction.

A Good pilot will practice until he gets it right,
A Great pilot will practice until he can’t get it wrong.
 

Read
« Reply #18 on: May 17, 2011, 07:26:19 AM »
PankajC
Plane Lover
Forum Hero

*****

Reputation Power: 13 
PankajC has no influence.
Offline Offline

City: Delhi
State: Delhi
RC Skills: Beginner
Posts: 1022
Join Date: Jul, 2009

Learning to Fly



while I am not an expert in any sense, leave alone for water takeoffs, but I did notice that the left wing is in contact with water while right one is not. Now, when in contact with water, that portion is putting in little bit of more resistance to forward motion than the other and hence could be the reason for left spin. It also could mean that your 2 halves of the wings are not of equal weight
Logged

Spektrum DX6i | EP Pusher Trainer | EP CUB |
 

Read
« Reply #19 on: May 17, 2011, 11:48:56 AM »
santhosh
Heli Lover
Forum Hero
*****

Reputation Power: 7 
santhosh has no influence.
Offline Offline

City: thrissur
State: Kerala
RC Skills: Beginner
Posts: 507
Join Date: Mar, 2009



direction maintenance on water is by maintaining wings level by moving aileron continuously, sounds funny but true.
thanks gusty, really valuable information  after a long time, i tried to correct the direction with rudder only, but on the initial
stages of take off it has no effect as the rudder is not touching the water , and if we increase the throttle the loop starts, next time will play with the ailerons but have to wait at least one month for the monsoon to come
« Last Edit: May 17, 2011, 12:21:06 PM by anwar » Logged
 

Read
« Reply #20 on: May 17, 2011, 12:21:57 PM »
anwar
Administrator
Forum Hero

*****

Reputation Power: 141 
anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!
Offline Offline

City: Doha (Qatar) & Thrissur
State: Kerala
RC Skills: Advanced
Posts: 11619
Join Date: Mar, 2009

RC India - Flying and racing with open minds !



It thought it had same behavior on the ground too ?
Logged

Hangar : Please see my introduction.
RC India forum and me : About this forum.
 

Read
« Reply #21 on: May 17, 2011, 04:13:29 PM »
rcpilotacro
Global Moderator
Forum Hero

*****

Reputation Power: 58 
rcpilotacro is on the verge of being accepted.rcpilotacro is on the verge of being accepted.rcpilotacro is on the verge of being accepted.rcpilotacro is on the verge of being accepted.rcpilotacro is on the verge of being accepted.
Offline Offline

City: Delhi
State: Delhi
RC Skills: Advanced
Posts: 5041
Join Date: Nov, 2010

Practice, and only Practice will make you perfect



wheel base and wheel track are very big factors in designing an aircraft, in fact this determines the undercarriage , wheel well, and fuel that it can carry due reduced fuel due to wheel well(When the undercarriage retracts) it is a very big topic,

in water however it is the fuse which is the hull, footprint of which is small , left/right dragging force that a port /stbd wheel can create on ground is absent on a hull, on the contrary some hull will produce reverse effect , (If you apply left rudder, it will turn to the right) that is why it is important to get wings level as quickly as one can, without applying too much of power till you get wings level. thereafter it is  a piece of cake
Logged

Gusty's Hangar and Introduction.

A Good pilot will practice until he gets it right,
A Great pilot will practice until he can’t get it wrong.
 

Read
« Reply #22 on: May 17, 2011, 04:21:19 PM »
anwar
Administrator
Forum Hero

*****

Reputation Power: 141 
anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!
Offline Offline

City: Doha (Qatar) & Thrissur
State: Kerala
RC Skills: Advanced
Posts: 11619
Join Date: Mar, 2009

RC India - Flying and racing with open minds !



It would be interesting to do some ground tests on a long piece of smoothly tiled floor (I guess after putting a bit of tape on the parts that would hit the ground).
Logged

Hangar : Please see my introduction.
RC India forum and me : About this forum.
 

Read
« Reply #23 on: May 17, 2011, 04:47:46 PM »
foamybuilder
Plane Lover
Forum Hero
*****

Reputation Power: 8 
foamybuilder has no influence.
Offline Offline

City: Bangalore
State: Karnataka
RC Skills: Intermediate
Posts: 626
Join Date: Sep, 2010



Make sure that both ESC are of same brand and same rating.
Logged
 

Read
« Reply #24 on: May 17, 2011, 04:56:14 PM »
rcpilotacro
Global Moderator
Forum Hero

*****

Reputation Power: 58 
rcpilotacro is on the verge of being accepted.rcpilotacro is on the verge of being accepted.rcpilotacro is on the verge of being accepted.rcpilotacro is on the verge of being accepted.rcpilotacro is on the verge of being accepted.
Offline Offline

City: Delhi
State: Delhi
RC Skills: Advanced
Posts: 5041
Join Date: Nov, 2010

Practice, and only Practice will make you perfect



Santhosh's electronics are always perfect, that's why i didn't question his build.
Logged

Gusty's Hangar and Introduction.

A Good pilot will practice until he gets it right,
A Great pilot will practice until he can’t get it wrong.
 

Read
« Reply #25 on: May 17, 2011, 05:45:20 PM »
anwar
Administrator
Forum Hero

*****

Reputation Power: 141 
anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!anwar is awe-inspiring!
Offline Offline

City: Doha (Qatar) & Thrissur
State: Kerala
RC Skills: Advanced
Posts: 11619
Join Date: Mar, 2009

RC India - Flying and racing with open minds !



Not the build... I suspected differential thrust.
Logged

Hangar : Please see my introduction.
RC India forum and me : About this forum.
 

Read
« Reply #26 on: May 17, 2011, 10:46:55 PM »
santhosh
Heli Lover
Forum Hero
*****

Reputation Power: 7 
santhosh has no influence.
Offline Offline

City: thrissur
State: Kerala
RC Skills: Beginner
Posts: 507
Join Date: Mar, 2009



Santhosh's electronics are always perfect, that's why i didn't question his build.
everything is as per the manual, used the suggested rimfire motors,esc's props etc.for my  mpx twinstar  i cut the centre lead of one of the esc's and conected it through  a y cable to the rx,for the catalina i didn't. connected the two esc's to a y cable and to the rx as the manual says so, not sure that make a big difference  Bang Head
Logged
 

Pages: 1 2 [All]   Go Up
Jump to:  

Related Topics
Subject Started by Replies Views Last post
Needed FMA CO-PILOT
Self-designed, DIY and College Projects
paddy7789 13 6545 Last post July 10, 2010, 06:56:43 PM
by sandyjain
If anything Needed « 1 2  All »
RC Outlets and Resellers
chkalyan 26 17108 Last post September 06, 2010, 12:21:13 PM
by flyingboxcar
Hi all - Car help needed
Beginners Zone
dskumar_2000 3 4061 Last post November 14, 2010, 10:57:35 AM
by above the limt
help needed!!!
Wanted
arjun2592 3 3172 Last post March 06, 2011, 07:01:32 AM
by rcpilotacro
Micro Consolidated PBY Catalina flying boat
Electric Planes
DominicM 0 1099 Last post October 18, 2019, 03:04:27 PM
by DominicM