USB Camera - Stabiity issues

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Number_6

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Has anyone else had stability issues when mounting a USB camera to a fuselage.

I mounted one to a Model Estes Yankee and launched with a B4-4. Launch ended up horizontal. Not good.

An Estes M-104 US Army Patriot and C6-7 was better but the delay to fire the parachute was I believe too long, resulting in a near ballistic arc.

Any advice?

Be seeing you,

6
 
Not sure which camera you're talking about. I've had pretty good success attaching key fob cameras and now the Mobius Action Cam to rockets when putting them about at the loaded CG. But the model has to be big enough and the power great enough (and the delay short enough) to deal with the extra drag and mass. A key fob cam on a model the size of the Yankee is really iffy. If your camera is quite a bit smaller, maybe it'd work - again with the camera at about the balance point or a bit forward of that point (so the extra weight helps the stability and offsets the extra drag).

A 7 second delay on the Patriot would be too long even without a camera stuck on the side....
 
I'll upload some photos. I think there was more than enough boost on the Yankee but the weight and drag clearly messed it up. The video is wild. When I edit it I'll upload that too. I mounted the cameras at roughly the fin tops so I suspect behind the CG.
 
I always put them close to the nose and never had a problem.
 
Close to the nose moves the CG forward, which is what you want to increase stability. At least mount it forward of the current CG so that the CG does not move towards the CP. CP should be aft of the CG by at least 1 to 1.5 body tube widths (caliber).
 
jrkennnedy2 said:
Close to the nose moves the CG forward, which is what you want to increase stability. At least mount it forward of the current CG so that the CG does not move towards the CP.
Click to expand...

+1 but your main problem is that the delay was too long. Maybe a C6-5 or even C6-3 next time.
 
You shouldn't be launching so close to houses; you should be in an open field or a park. I would try C6-3 next time.
 
I use the same model USB camcorder.... (on L and M powered rockets) ... several strip of black electrical tape instead of masking or painters tape... make sure you get a few strips all the way around the rocket so it doesn't peal off.
 
IMG_8222.JPGIMG_8223.JPGIMG_8224.JPGIMG_8225.JPGIMG_8226.JPGIMG_8228.JPG
I taped an 808 #16 keychain camera to my Estes Patriot and drilled 4 evenly spaced holes around the body tube just below the nose cone for the Estes altimeter.
I sent it up with a C6-5 engine and it made almost a 90 degree angle by the end of its thrust from the off centered weight of the camera.
The Altimeter reading was only 288Ft. so at a 5 second delay, it had gone ballistic coming straight down ready for a lake stake. The parachute finally ejected just seconds before crashing and bringing the rocket to safety without a scratch. I couldn't imagine putting a C6-7 engine with that much delay. A C6-3 would be a better option next time with this set up. I regret not upgrading to a D-E for this rocket for the payloads I would like to send up. The C engines work great on a stock patriot as long as you don't add extra cargo.


The NO.2 pencil worked fabulous with this camera set up and was very straight and stable reaching over 400 ft. on the Altimeter.
 
Last edited:
To consolidate the comments.

1.) The M104 Patriot is 1.64" OD and will weigh about 2 oz. according to Estes without a motor.

2.) The recommended motor is a C6-5.

3.) An 808 #16 weighs ~18 grams and is 50 mm x 32 mm x 13 mm

4.) Aerodynamically speaking this adds 416 mm^2 of cross-sectional area.

5.) This can be modeled as a 1.90" OD rocket weighing ~3 oz. without the motor.

6.) The proper motor is a C6-3 for an apogee ~450' if the rocket goes straight. and will have a lift-off weight just below 4 oz.

7.) If you mount it near the bottom of the rocket as you did, the rocket will arc over severely.

8.) The camera should be mounted just below the nosecone to keep the center of gravity ahead of the center of pressure by several calibers (diameters) so the rocket will have a large stability factor.

General comment. When you launch in a small field don't launch if the wind is stronger that about 5 mph. A rocket that apogees at 450' will drift 450' sideways in a 10 mph wind, half that in a 5 mph wind and twice that if the wind is 20 mph. If you are launching to a nominal 500', your minimum field dimension should be 1/2 of that or 250'. In a 5 mph wind the rocket drifts 225' sideways so if the wind is much higher it will not recover in the launch field.

Bob
 
bobkrech said:
To consolidate the comments.

1.) The M104 Patriot is 1.64" OD and will weigh about 2 oz. according to Estes without a motor.

2.) The recommended motor is a C6-5.

3.) An 808 #16 weighs ~18 grams and is 50 mm x 32 mm x 13 mm

4.) Aerodynamically speaking this adds 416 mm^2 of cross-sectional area.

5.) This can be modeled as a 1.90" OD rocket weighing ~3 oz. without the motor.

6.) The proper motor is a C6-3 for an apogee ~450' if the rocket goes straight. and will have a lift-off weight just below 4 oz.

7.) If you mount it near the bottom of the rocket as you did, the rocket will arc over severely.

8.) The camera should be mounted just below the nosecone to keep the center of gravity ahead of the center of pressure by several calibers (diameters) so the rocket will have a large stability factor.

General comment. When you launch in a small field don't launch if the wind is stronger that about 5 mph. A rocket that apogees at 450' will drift 450' sideways in a 10 mph wind, half that in a 5 mph wind and twice that if the wind is 20 mph. If you are launching to a nominal 500', your minimum field dimension should be 1/2 of that or 250'. In a 5 mph wind the rocket drifts 225' sideways so if the wind is much higher it will not recover in the launch field.

Bob
Click to expand...
Thanks for educating me with all these factors in detail. Can't wait till next launch to try out my new lesson from your science class.
 
I have a slightly different approach to stability with a larger rocket (scratch built 54mm) with an 808 camera. I placed the camera relatively far aft, behind the marked CP. That way, the drag of the camera mount is aft of the CP mark and I know my CP is no further forward than the mark. I can then use the distance between the marked CP and measured CG from a balance test to make sure I have adequate stability. This rocket has lots of weight forward, so stability hasn't been an issue so far. This method obviously only works for a rocket where you know the CP and check CG location before flight.

This is what made sense to me. I'm always willing to be proven wrong!
 

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