New Products Flash Sale
Thread Tools
Old Aug 10, 2015, 04:25 AM
taylansplace is offline
Find More Posts by taylansplace
Registered User
Joined Dec 2011
25 Posts
Discussion
80" super cub crash report

Hi Guys,

I have crashed my cub this weekend.
Could you please watch the video and leave a comment about what could cause the crash?

Video:
Hobbyking Super Cub EP 80" Crash Report (1 min 13 sec)


The CG was correct.
I simply measured the veritical stability holding from the motor mil and back landing gear.
There was no wind.
Elerons seemed to be on 0 degree.
The plane was turning to the left(eleron).
I used full right eleron to avoid the crash but not worked.


My plane:
http://www.hobbyking.com/hobbyking/s..._80in_ARF.html

Motor: Hobbyking G60
ESC: 60amp
Prop:15x8
Lipo:6S 5000mAh
(thrust was ok)
taylansplace is offline Find More Posts by taylansplace
Reply With Quote
Sign up now
to remove ads between posts
Old Aug 10, 2015, 05:10 AM
dreisinger is offline
Find More Posts by dreisinger
Registered User
United States, PA, Carlisle
Joined Oct 2011
540 Posts
Controls were free and correct prior to take-off?
dreisinger is offline Find More Posts by dreisinger
Reply With Quote
Old Aug 10, 2015, 05:46 AM
taylansplace is offline
Find More Posts by taylansplace
Registered User
Joined Dec 2011
25 Posts
Yes i have checked all controls before flight and i was taking off against to the wind..
taylansplace is offline Find More Posts by taylansplace
Reply With Quote
Old Aug 10, 2015, 09:30 AM
Super Six 7 is offline
Find More Posts by Super Six 7
Registered User
Australia, SA, Old Noarlunga
Joined Mar 2012
145 Posts
Looks like aileron reversal - they were connected the wrong way.
Super Six 7 is offline Find More Posts by Super Six 7
Reply With Quote
Old Aug 10, 2015, 09:51 AM
taylansplace is offline
Find More Posts by taylansplace
Registered User
Joined Dec 2011
25 Posts
Quote:
Originally Posted by Super Six 7 View Post
Looks like aileron reversal - they were connected the wrong way.
at the beginning with no aileron command the plane turned left veritically.
When i give right command she tried to turn right but was not enough
taylansplace is offline Find More Posts by taylansplace
Reply With Quote
Old Aug 11, 2015, 07:52 AM
taylansplace is offline
Find More Posts by taylansplace
Registered User
Joined Dec 2011
25 Posts
One of my friend told me that the problem might be the motor angle, could it be?
taylansplace is offline Find More Posts by taylansplace
Reply With Quote
Old Aug 11, 2015, 09:59 AM
eflightray is online now
Find More Posts by eflightray
An itch?. Scratch build.
eflightray's Avatar
South Wales U.K.
Joined Mar 2003
16,473 Posts
Using full screen and the Pause/Play to do a stop/start motion -

At the first attempt there was about 45 deg of up elevator just before it ran off the concrete.

I could not see any aileron movement. Usually that close to the model, (first attempt again), you should see some difference.

I would guess, you either had the ailerons reversed, or there is a major twist/warp in the wing. I don't think prop torque was the problem. If there had been a wind, it would have looked like a classic take-off across the wind.

Questions -

Is this your first RC plane ?
Did you do a though check of all controls in accordance with the instructions ?, (to turn right, the right aileron goes up, the left aileron goes down.)
Did you do a radio range check to make sure the radio link had suitable range. ?

If you have never flown a radio control model before, then it is very easy to be in too much of a rush to get it airborne.
It's very easy to just 'waggle the sticks' to see the controls move, without checking they really do move in the correct direction.
It's very easy to assume the radio works at a distance, just because it does up close.
It's very ease to just keep trying if you have friends watching, when you should shut the throttle and sort out an obvious problem.
eflightray is online now Find More Posts by eflightray
Reply With Quote
Old Aug 12, 2015, 05:38 AM
taylansplace is offline
Find More Posts by taylansplace
Registered User
Joined Dec 2011
25 Posts
Quote:
Originally Posted by eflightray View Post
Using full screen and the Pause/Play to do a stop/start motion -
Thanks for your time!

Quote:
Originally Posted by eflightray View Post
At the first attempt there was about 45 deg of up elevator just before it ran off the concrete.-
I have moved up the elevator after i stopped the motor.

Quote:
Originally Posted by eflightray View Post
I could not see any aileron movement. Usually that close to the model, (first attempt again), you should see some difference.
.-
at first attempt i did not give any aileron command, when she turned left i suddenly stopped the motor.

Quote:
Originally Posted by eflightray View Post
I would guess, you either had the ailerons reversed,
-
I was pretty sure that the ailerons were correct.

Quote:
Originally Posted by eflightray View Post
or there is a major twist/warp in the wing.-
I believe this is the strongest idea.. I will check the wings and wing connections one more time at home today.

Quote:
Originally Posted by eflightray View Post
I don't think prop torque was the problem. -
I dont think so too, the turn is so strong for a prop problem.

Quote:
Originally Posted by eflightray View Post
If there had been a wind, it would have looked like a classic take-off across the wind.-
Yes, there were no wind.


Questions -

Quote:
Originally Posted by eflightray View Post
Is this your first RC plane ?
No, i have several rc planes.

Quote:
Originally Posted by eflightray View Post
Did you do a though check of all controls in accordance with the instructions ?, (to turn right, the right aileron goes up, the left aileron goes down.)
Yes, i did prefight tests and everything was correct.


Quote:
Originally Posted by eflightray View Post
Did you do a radio range check to make sure the radio link had suitable range. ?
Yes, the same rx/tx were working on another planes before and i also did the range test with this plane.

Quote:
Originally Posted by eflightray View Post
If you have never flown a radio control model before, then it is very easy to be in too much of a rush to get it airborne.
It's very easy to just 'waggle the sticks' to see the controls move, without checking they really do move in the correct direction.
It's very easy to assume the radio works at a distance, just because it does up close.
It's very ease to just keep trying if you have friends watching, when you should shut the throttle and sort out an obvious problem.
I agree on all of above ideas. Thanks for the advices.
taylansplace is offline Find More Posts by taylansplace
Reply With Quote
Old Aug 12, 2015, 08:04 AM
Glacier Girl is offline
Find More Posts by Glacier Girl
Kamikaze Ace
Glacier Girl's Avatar
USA, FL, Lakeland
Joined Jan 2010
3,416 Posts
Have to agree with the others, it looked like a classic case of reversed ailerons.
As it started to bank left, there was a sudden snap left. What I would expect if the ailerons were reversed and right aileron was applied to try and correct.

Also Cubs and such need rudder to control them on the ground, a lot. Would help counter act the turn to the left and the right wing lifting on take off.
Glacier Girl is offline Find More Posts by Glacier Girl
Reply With Quote
Old Oct 02, 2015, 01:54 AM
Rampage is offline
Find More Posts by Rampage
DFS#000178
Rampage's Avatar
United States, CA, Twentynine Palms
Joined Aug 2005
6,335 Posts
Quote:
Originally Posted by Glacier Girl View Post
Also Cubs and such need rudder to control them on the ground, a lot. Would help counter act the turn to the left and the right wing lifting on take off.
This can never be overstated. Most airplanes turn with the ailerons with rudder input to coordinate the turn.

Cubs turn with the rudder and aileron input to coordinate the turn.

A model Cub that flies like a Cub is very difficult to actually fly well.

You can get away with bank-and-yank with a Cub, but it's one of the few airplanes that makes it obvious that you're bank-and-yanking. They look terrible in the air when flown without huge amounts of rudder.
Rampage is offline Find More Posts by Rampage
Reply With Quote
Old Oct 22, 2015, 03:23 PM
Jim.Thompson is online now
Find More Posts by Jim.Thompson
Entropy is happening!
Jim.Thompson's Avatar
Australia, NSW, Bellingen
Joined Aug 2008
8,876 Posts
Quote:
Originally Posted by Glacier Girl View Post
Have to agree with the others, it looked like a classic case of reversed ailerons.
.................................
I certainly looks like it from the video!
Jim.Thompson is online now Find More Posts by Jim.Thompson
Reply With Quote
Old Nov 22, 2015, 07:57 AM
ARUP is offline
Find More Posts by ARUP
Registered User
Joined Mar 2010
2,608 Posts
I never once saw the ailerons move in the vid although that doesn't mean the controls weren't operative. That Cub sure seemed to be flying too slow at lift off and was in ground effect. Continued elevator input to gain height caused it to slow down more which reduces control inputs' effectiveness. Thus, it rolled even more as it got greater than one wingspan height in altitude. Either the ailerons weren't connected, they were reversed or they didn't have enough throw. Cubs can be notorious for tip stalling if no washout built into the wings and they are flown too slowly. I have a Cub that size that I like to fly slowly. I reflexed the ailerons upwards 1/8" (~3mm) after the first flight. It flies great but will still drop a wing (the left one- my wings are dead nuts straight) in the blink of an eye if flown too slowly!
Hope you can repair it and have success. Cubs are fun little machines!
ARUP is offline Find More Posts by ARUP
Last edited by ARUP; Nov 22, 2015 at 10:13 AM. Reason: I saw rudder move!
Reply With Quote
Old Feb 07, 2016, 05:06 AM
Chris Jenkins is offline
Find More Posts by Chris Jenkins
Registered User
Chris Jenkins's Avatar
United Kingdom, Wales
Joined Feb 2005
1,065 Posts
My opinion is that this looks like typical tail-dragger pull to the left on take off. You need to correct this with right rudder, and NOT ailerons. Using aileron just create drag and make the situation worse.

So.... add more right thrust, don't use ailerons until you have built up a god margin of flying speed, and correct any take-off drift to the left with good boot of right rudder. Don't hold it on, but just dab it in and release. A good hand launch will also be a solution (But check that you have at least 2 degrees of right thrust built in to you motor installation.

Good Luck !

Chris
Chris Jenkins is offline Find More Posts by Chris Jenkins
Reply With Quote
Old Feb 07, 2016, 02:22 PM
balsabuser is online now
Find More Posts by balsabuser
Registered User
Joined Feb 2016
195 Posts
Like what was all ready said, the larger the plane, the more it has to be flown like its full size counter part ( Use of rudder in a tail dragger, especially a larger model is required on take off and landing). It does not look like it has a lot of power or you did not have full throttle. Fulll throttle on take off will give you more control authority and you will get off the ground much faster( less time for trouble).
balsabuser is online now Find More Posts by balsabuser
Reply With Quote


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion PIper Super Cub Crashes on CA Beach dlazarus6660 General Aviation 1 Aug 05, 2015 09:14 PM
Discussion Recently Crashed Hobby Zone Super Cub Question CM3607 Crash Discussion 3 Jul 14, 2015 02:35 PM
Discussion V765-2 super cub noise dive and crash yu254445 Beginner Training Area (Aircraft-Electric) 2 Jun 10, 2015 03:01 AM
Build Log Page 80" Super Cub build rtibbs Balsa Builders 15 Apr 23, 2015 02:44 PM
Sold Hobbyzone Super Cub Brushless 480 with Battery 80$ shipped MIKEYOUR Aircraft - Electric - Airplanes (FS/W) 3 Dec 15, 2013 10:31 AM