VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.


Go Back   VAF Forums > Main > Safety
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 06-15-2014, 04:15 PM
scard's Avatar
scard scard is offline
 
Join Date: Jun 2005
Location: Cedar Park, TX
Posts: 3,229
Default How NOT to mount a GoPro camera (on a -9)

I've seen this so many times and thought I would give it a whirl. So I spent a few minutes in the shop with my spare fuel cap. We all travel with one, right? Picture worth a thousand words:



Looks like this on the airplane, was rotated about 40deg from straight on.



Every change obviously requires a flight test, or two, or however many it takes, no matter how small. To our amazement, this configuration increased the clean stall speed (no flaps) by 12 knots! Our airplane stalls beautifully at about 52kts clean. With the camera there, it was stalling at 64kts! You could tell something wasn't right while slowing through 80kts. By 70kts it felt down right mushy. This is not what our RV feels like at all. Of course the first indication was the noticeably longer takeoff roll. The effect on stall speed with flaps down was far less.

Maybe the -9 wing is very unique with the effect of this mount, but I've seen this setup so many times. Please be sure you really flight test it.

Now, just as a thought exercise, I wonder just how long the mount stud would need to be to not have the huge adverse effect on stall characteristics?

We're still amazed at the effect. Experiment carefully as I will continue to do .
__________________
Scott Card
CQ Headset by Card Machine Works
CMW E-Lift
RV-9A N4822C flying 2200+hrs. / Cedar Park, TX
RV8 Building - fuselage / showplanes canopy (Done!)
VAF Advertiser
Reply With Quote
  #2  
Old 06-15-2014, 04:26 PM
Mike S's Avatar
Mike S Mike S is offline
Senior Curmudgeon
 
Join Date: Sep 2005
Location: Dayton Airpark, NV A34
Posts: 15,837
Default

So, when it did stall, was there any tendency to try to enter a spin??
__________________
Mike Starkey
VAF 909

Rv-10, N210LM.

Flying as of 12/4/2010

Phase 1 done, 2/4/2011

Sold after 240+ wonderful hours of flight.

"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."
Reply With Quote
  #3  
Old 06-15-2014, 04:42 PM
scard's Avatar
scard scard is offline
 
Join Date: Jun 2005
Location: Cedar Park, TX
Posts: 3,229
Default

Quote:
Originally Posted by Mike S View Post
So, when it did stall, was there any tendency to try to enter a spin??
There would have been no value in me exploring it that deeply. I have a rudder the size of Texas that gives tons of control, I didn't take it that deep. Once we proved that this was clearly an undesirable configuration, the flight test was terminated. Once back over the field at 6k', I did have to evaluate the safest configuration to get it back on the ground, which was full flaps. Sound familiar? Boy, we were right back in phase I in an instant.

I'm going to say it again, there must be people out flying around that haven't even tested the basics since I'm the first that I can find to report adverse effects (that are huge).
__________________
Scott Card
CQ Headset by Card Machine Works
CMW E-Lift
RV-9A N4822C flying 2200+hrs. / Cedar Park, TX
RV8 Building - fuselage / showplanes canopy (Done!)
VAF Advertiser
Reply With Quote
  #4  
Old 06-15-2014, 04:50 PM
rv7boy's Avatar
rv7boy rv7boy is offline
Forum Peruser
 
Join Date: Jan 2005
Location: Austinville, Alabama
Posts: 2,469
Default

Seems like I read that the great air show pilot and Hollywood movie pilot Art Scholl was experimenting with different camera locations on the wing of his camera plane while shooting air scenes for the Top Gun movie and may have affected the air flow such that he couldn't recover from an inverted spin. I'm thinking neither he nor his camera plane were ever found.

If it could happen to him, it could happen to us.
__________________
Don Hull
RV-7 Wings
KDCU Pryor Field
Pilots'n Paws Pilot
N79599/ADS-B In and Out...and I like it!

?Certainly, travel is more than the seeing of sights;
it is a change that goes on, deep and permanent, in the ideas of living." Miriam Beard

Last edited by rv7boy : 06-15-2014 at 08:41 PM.
Reply With Quote
  #5  
Old 06-15-2014, 06:08 PM
rockwoodrv9 rockwoodrv9 is offline
 
Join Date: Dec 2011
Location: Meridian ID, Aspen CO, Okemos MI
Posts: 2,717
Default

Scott, I have wondered about how the camera would change the flight characteristics. If tiny little vortex generators can make as much of a difference that they do make, a camera bigger than all of them combined will for sure be felt.

I have seen many videos, including one posted today flying up the coast of Florida and no reported problems. I appreciate you reporting the issues you had. I am really interested in others experiences too.

A month or so ago, someone posted a video of little strings all over his wings and how they changed in flight and what happened as they went into a stall. Maybe with that video a place could be found on the wing or other part of the plane that wouldn't cause an increase in stall speed.

I am still building so I don't have the experience with the fuel caps other than the few times while doing the tanks to know how solid they are mounted. Is there a chance that the camera could cause the catch to fail and you end up with an open fuel tank?

This will be interesting. Thanks for reporting what you experienced in your flight. I bet it was puzzling and took a bit of time to understand what was going on.
__________________
rockwoodrv9a
Williamston MI
O-320 D2A
Flying N376E
Reply With Quote
  #6  
Old 06-15-2014, 06:32 PM
scard's Avatar
scard scard is offline
 
Join Date: Jun 2005
Location: Cedar Park, TX
Posts: 3,229
Default

Quote:
Originally Posted by rockwoodrv9 View Post

I am still building so I don't have the experience with the fuel caps other than the few times while doing the tanks to know how solid they are mounted. Is there a chance that the camera could cause the catch to fail and you end up with an open fuel tank?

This will be interesting. Thanks for reporting what you experienced in your flight. I bet it was puzzling and took a bit of time to understand what was going on.
The caps aren't a concern yet. The plastic in the camera mount are going to fail before the cap pops out. Force given an aerodynamic area are pretty easy to test doing zero knots on the ground. Math is easy, surviving is sometimes a little harder .

The beauty of having a very proven airframe with which you have a perfect relationship for 7+yrs in the hands of pilots that are perfectly in tune with the exact expected performance of that airframe, to within a knot or two, is that it took no time at all to see that something significant was different. There was no puzzle to solve except for what just changed (obvious). Now how to get back on the ground with the most margin possible.

Keep 'em coming, the percent performance change amazed my little brain.
__________________
Scott Card
CQ Headset by Card Machine Works
CMW E-Lift
RV-9A N4822C flying 2200+hrs. / Cedar Park, TX
RV8 Building - fuselage / showplanes canopy (Done!)
VAF Advertiser
Reply With Quote
  #7  
Old 06-15-2014, 06:57 PM
ArlingtonRV ArlingtonRV is offline
 
Join Date: Feb 2005
Location: Marysville, WA
Posts: 538
Default Not a Go PRo

I've never used a Go Pro, but the mount for my Drift HD Ghost resulted in no real noticeable changes in flying characteristics. I think it costs me about a knot in cruise, but had no measurable affect on stall characteristics or speed.

I use the "Spud Mount" from N Flight Cam: http://nflightcam.com/store/index.ph...ting-spud.html

It looks like this.


__________________
Steve Rush
Arlington, WA
ArlingtonRV on YouTube
RV-8 (Bought Flying)
Glasair Sportsman (Sold)
RV-8 Tail, QB Fuselage (Sold)
RV-4 (Bought Flying) (Sold)
RV-9 Tail
RV-12 120018 Flying (Sold)
RV-7 Tail, Wings, Started Fuse (Sold)
Reply With Quote
  #8  
Old 06-15-2014, 08:54 PM
RV6_flyer's Avatar
RV6_flyer RV6_flyer is offline
 
Join Date: Jan 2005
Location: NC25
Posts: 3,635
Default GearPro Tests

I have been testing a GearPro mounted using wingtip screw with camera pointing at the airplane. Did two flights without turning the camera on just to test the mount and location. So far, no effect found on flight characteristics but have had NO good in flight video yet. It fogs up inside the case! Have tried two desiccant strips and then four desiccant strips. The 4-strips help but still get fogging on the inside lens of the case. Have Ant-Fog spray ordered to try next.

Your experience tells me that I need to flight test other mounting locations that I have planned before putting the camera(s) into full use.

My ContourHD camera has been flight tested in all its possible mounting locations before actually using it to record wanted video. NONE of the locations that I use have are on top of the wing that did not use a location on the wing tip. ContourHD forward facing on wingtip works as does under wing using tiedown mount bolt hole. Tiedown bolt hole looking forward does not work for formation flying as all you get is the wheel pants of the aircraft in front. Looking back works fine.

Thanks for sharing the additional test location that I had not thought about. I know it is one that I will not use based on your test data. Yes I do carry as spare fuel cap in my tool kit.
__________________
Gary A. Sobek
NC25 RV-6
Flying
3,400+ hours
Where is N157GS
Building RV-8 S/N: 80012

To most people, the sky is the limit.
To those who love aviation, the sky is home.
Reply With Quote
  #9  
Old 06-15-2014, 11:25 PM
RV7A Flyer's Avatar
RV7A Flyer RV7A Flyer is offline
 
Join Date: Jul 2013
Location: US
Posts: 2,405
Default

I've used the NFlightCam mounting spud and swivel (ball joint) mount for the GoPro, mounted on the outboard aftmost fuel tank screw, upper wing surface, and noticed no change in handling or performance.

I have a friend who mounted a GoPro on the *bottom* of the wing (don't know the exact location) who reported a "huge" change in yaw. We surmised that it might have been mounted closer to the wing surface, resulting in disturbed airflow closer to the boundary layer, and thus created more of an effect than the NFlightCam (and my positioning) putting the camera higher and thus further from the boundary layer on top.

But that's all speculation...I just know my location works just fine with no adverse effects.
Reply With Quote
  #10  
Old 06-16-2014, 03:39 AM
Arlen's Avatar
Arlen Arlen is offline
 
Join Date: Sep 2013
Location: New Smyrna Beach, FL
Posts: 305
Default

Quote:
Originally Posted by RV7A Flyer View Post

But that's all speculation...I just know my location works just fine with no adverse effects.
I would GUESS that location on the aircraft and separation distance in the particular locations result in different effects.

The location and separation I used yesterday had no obvious impact on flight: http://www.vansairforce.com/communit...ighlight=Polar

.
__________________
Arlen
Donation to VAF 10.29.18
RV-6, February '14, SOLD December '15
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 09:53 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.