SkyFun III: new ideas for managing CG shift

the model rocket show
rocket sok
shop deals on amazon
The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Here's a sample of the log file (around first flight's apogee; it logs altitude in meters even when UI is in feet). You can see that it logs at about 9-10Hz, but altimeter data changes only about twice a second.

Code: 
Date,Time,SWR,RSSI,A1,A2,GPS Date,GPS Time,Long,Lat,Course,GPS Speed,GPS Alt,Baro Alt,Vertical Speed,Temp1,Temp2,RPM,Fuel,Cell volts,Cell 1,Cell 2,Cell 3,Cell 4,Cell 5,Cell 6,Current,Consumption,Vfas,AccelX,AccelY,AccelZ,Rud,Ele,Thr,Ail,S1,S2,LS,RS,SA,SB,SC,SD,SE,SF,SG,SH

[..]

2014-03-24,11:59:49.610,0,49,6.47,2.60,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 233.69, 10.23,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-8,89,0,-3,-32,-982,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:49.720,0,49,6.47,2.60,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 233.69, 10.23,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-8,89,0,-3,-32,-982,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:49.820,0,49,6.47,2.60,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 233.69, 10.23,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-8,89,0,-3,-32,-982,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:49.920,0,52,6.47,2.60,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 238.50, 9.62,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-4,-8,89,-1,-2,-31,-980,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:50.030,0,52,6.47,2.60,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 238.50, 9.62,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-4,-8,89,-1,-3,-32,-982,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:50.140,0,52,6.47,2.60,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 238.50, 9.62,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-8,89,-1,-3,-32,-982,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:50.240,0,52,6.47,2.60,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 238.50, 9.62,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-4,-8,95,0,-3,-32,-982,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:50.340,0,52,6.47,2.60,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 238.50, 9.62,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-8,114,-1,-3,-32,-980,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:50.440,0,52,6.47,2.60,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 238.50, 9.62,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-8,156,-1,-3,-32,-982,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:50.540,0,52,6.47,2.60,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 240.44, 3.88,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-4,-8,157,0,-3,-32,-982,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:50.650,0,52,6.47,2.60,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 240.44, 3.88,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-4,-8,157,-1,-1,-31,-980,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:50.750,0,57,6.47,2.27,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 240.44, 3.88,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-4,-8,157,0,-3,-32,-980,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:50.850,0,57,6.47,2.27,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 240.44, 3.88,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-8,161,0,-3,-32,-982,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:50.950,0,57,6.47,2.27,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 240.81, 0.00,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-8,172,0,-3,-32,-982,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:51.060,0,57,6.47,2.27,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 240.81, 0.00,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-4,-8,221,0,-3,-32,-982,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:51.160,0,68,6.47,2.27,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 240.81, 0.00,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-4,-8,224,0,-3,-32,-982,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:51.280,0,68,6.47,1.65,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 240.81, 0.00,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-8,361,0,-3,-32,-982,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:51.380,0,68,6.47,1.65,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 240.81, 0.00,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-4,-8,491,-1,-4,-32,-982,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:51.500,0,68,6.47,1.65,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 239.25, 0.00,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-8,581,-2,-3,-32,-982,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:51.620,0,51,6.47,1.65,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 239.25,-3.12,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-8,645,-2,-3,-32,-982,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:51.740,0,51,6.47,1.15,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 239.25,-3.12,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-1,-8,773,-2,-3,-32,-980,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:51.860,0,51,6.47,1.15,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 239.25,-3.12,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-1,-8,831,-2,-3,-32,-982,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:51.960,0,51,6.47,1.15,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 235.50,-7.50,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-8,846,-1,-3,-32,-982,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:52.080,0,54,6.47,0.44,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 235.50,-7.50,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-1,-8,902,-1,-3,-32,-982,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:52.200,0,54,6.47,0.44,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 235.50,-7.50,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-8,903,-1,-3,-33,-983,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:52.320,0,54,6.47,0.44,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 235.50,-7.50,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-8,903,-1,-3,-32,-982,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:52.440,0,54,6.47,0.44,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 235.50,-7.50,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-8,905,-1,-2,-31,-979,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:52.540,0,62,6.47,0.73,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 232.69,-5.62,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-8,903,-1,-3,-32,-982,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:52.640,0,62,6.47,0.73,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 232.69,-5.62,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-8,903,-1,-3,-32,-980,-1024,1,1,1,1,1,1,-1,-1
2014-03-24,11:59:52.740,0,62,6.47,0.73,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 232.69,-5.62,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-1,-8,903,-1,-3,-32,-982,-1024,1,1,1,1,1,1,-1,-1
 
Thats good enough to see how various S8 configurations boost. The high precision would only be of more use for thermal hunting if the report is only 2/sec Taranis, 1/sec DHT-U and i'm not sure thats legal in contests. I'm hoping to build a few different wings for differing conditions and it would be good to know if one was bogus.

Thanks again Ari.


Richard
 
Last edited:
As far as I can tell, there is no restriction on telemetry in S8 like there is in F3K.
 
After half a dozen trouble-free flights, Cesaroni F51 decides to blow the top and torch my glider from the inside.

IMG_3019.jpg

First .75 seconds of the flight are nominal. Then I see the canopy fly off and glider changes path abruptly.
2.jpgScreen Shot 2014-04-05 at 11.20.52 PM.pngScreen Shot 2014-04-05 at 11.21.25 PM.png

Then I realize glider is on fire and I have no control.
Screen Shot 2014-04-05 at 11.22.05 PM.pngScreen Shot 2014-04-05 at 11.22.43 PM.png

It comes down surprisingly slowly, like a falling leaf. It touches down softly, the fire still raging. I race to extinguish the fire. To my surprise, I find all internal electronics missing--the initial blast had blown them out with the canopy. We eventually find them, torched and black, sprawled on adjacent pads.
3.jpgScreen Shot 2014-04-05 at 11.22.54 PM.pngScreen Shot 2014-04-05 at 11.24.22 PM.png


Pro 24: A better way to fly(tm)
I put vendor stickers on rockets that actually use that vendor's products. Ironically, only surviving part of the canopy is the one with CTI sticker.
IMG_3019cr.jpg
 
Ohhh, man, VERY sorry for this, Ari!!

Since this 'skyfun' appears to be a kit or "ARF", I guess you can get and mod another. Give you a good reason to make it with a 29mm MMT too.

Ive had a handful of 'fire in the sky' glider happenings before. Mainly caused by overly hot ejection charges on something intended to return as an all-up RG. Had a 7 foot long swing wing 'scrawler' type go up Hindenburg style years ago as it was entirely made of Readiboard and the CATO set it alight. Never saw anything burn *that* fast!!
 
Almost a year later, I have a new SkyFun. This iteration is very similar to the previous one. It's a little simpler in that it's missing the fiberglass tape reinforcement.

SkyFun IV is two weeks old and has 8 flights on it, three of them at SCCMAS yesterday. Walter Colby put together a video of yesterday's flights from his own and Amy's footage. All three motors ate CTI F30.

[video=youtube;UtlgXsWK6Os]https://www.youtube.com/watch?v=UtlgXsWK6Os[/video]

Ari.
 
Have any of you experimented with water ballast for nose weight during boost? It's a system that allows a forward CG for boost, then drains off to an empty water tank and a more glider-like CG for the glide phase?
 
sepierce1950 said:
Have any of you experimented with water ballast for nose weight during boost? It's a system that allows a forward CG for boost, then drains off to an empty water tank and a more glider-like CG for the glide phase?
Click to expand...

George Gassaway did that with his Bell X-1. It's really only an issue if you absolutely need to put the motor in the rear of the model. Since we can design however we like, it's easy enough to put the motor where it will not affect the CG that much or will affect it favorably.

https://www.georgesrockets.com/GRP/Scale/X1.htm
 
sepierce1950 said:
Have any of you experimented with water ballast for nose weight during boost? It's a system that allows a forward CG for boost, then drains off to an empty water tank and a more glider-like CG for the glide phase?
Click to expand...

I have read others have, however that person said failure to drain = lawndart which cost him the aircraft. I don't remember who. [not George, though he may have had that issue too]

You might try mechanically shifting the CG if the airframe really needs it. I'm looking at canards Edmonds style which are RC operated i.e. neutral at boost then adjusted to take up the CG shift at appogee.


Richard
 

Similar threads

ReynoldsSlumber
Old tractors, new tractors: Flying Pitchfork, Cluster F, TetraJet
Replies
16
Views
607
cwbullet
cwbullet

Latest posts

Back
Top