Grant Petty
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  • Madison, WI
  • United States
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DIY catapult for 2.6m fixed-wing?

Started this discussion. Last reply by Grant Petty May 11. 9 Replies

I built a largish fixed-wing UAV (Hugin 2.6m, roughly 8 kg MTOW if I…Continue

Tags: fixed-wing, catapult

Is this new LiPo battery already dead on arrival?

Started Apr 25 0 Replies

Just unpacked a new 3s 1500mah LiPo I ordered from banggood.  It arrived a month or so ago, but I only now got around to using it.  I also got a second identical battery at the same time, which is…Continue

Tags: charging, health, battery, lipo

tethered test flying - can this be done safely?

Started Apr 5 0 Replies

I have a newly built 450mm quadcopter (approx. 850 grams, not counting battery) that is about ready for its maiden flight.  It's equipped with a Pixhawk2.1, and I've calibrated ESCs, magnetometers,…Continue

amperes/volt ratio for stock power brick?

Started Apr 5 0 Replies

I've just completed a quadcopter build using a Pixhawk2.1 with the stock power brick provided.  I've verified that the battery monitor displays the correct voltage, but I have no good way to measure…Continue

 

Grant Petty's Page

Latest Activity

Ted M replied to Grant Petty's discussion Has anyone assembled this fixed-wing UAV airframe (Hugin 2.6m)?
"Grant, glad your maiden went well. This plane is definitely not for beginners.  Moving the main wheels closer to the CG is OK, if you're sure about your CG location. The gear should always be in front of the CG by some margin to encourage…"
yesterday
Grant Petty replied to Grant Petty's discussion Has anyone assembled this fixed-wing UAV airframe (Hugin 2.6m)?
"Ted, We've only flown it once! For me, a relatively new RC pilot, it was a "holding the tiger by its tail" kind of moment, and I was glad to have a more experienced pilot at the controls. As you noted, the aircraft is fast and needs…"
yesterday
Ted M replied to Grant Petty's discussion Has anyone assembled this fixed-wing UAV airframe (Hugin 2.6m)?
"Grant, you've probably flown the plane by now, how was your experience?  I have the inverted V-tail version of this vehicle with a dozen flights on it. Runtime is about 30 mins with 6s 10Ah batteries. Top speed with 12x8 APC prop is 76 mph…"
yesterday
Grant Petty replied to Grant Petty's discussion DIY catapult for 2.6m fixed-wing?
"Here's a better link focusing more on the bungee launcher: https://www.youtube.com/watch?v=xDwImUzHHkM"
May 11
Grant Petty replied to Grant Petty's discussion DIY catapult for 2.6m fixed-wing?
"Great points. Looking forward to seeing your new product when it comes out. BTW,here's a video I just found of a bungee launcher that seems to do a nice job with the Skywalker X8: https://www.youtube.com/watch?v=PqEESKzy_iQ"
May 11

Moderator
Dwgsparky replied to Grant Petty's discussion DIY catapult for 2.6m fixed-wing?
"1)  Yes, I refer to the skywalker X8 but they are usually loaded with heavy batteries and you wont hand launch these beasts. do a search for the injuries caused to people trying to do that. they are also far from flimsy.  2) yes and no, We…"
May 11
Grant Petty replied to Grant Petty's discussion DIY catapult for 2.6m fixed-wing?
"David, Thanks for the additional comments and info.  A couple of quick comments/questions for now: 1)  Is this the Skywalker X8 you're talking about?  https://hobbyking.com/en_us/skywalker-x-8-fpv-uav-flying-wing-2120mm.html…"
May 11

Moderator
Dwgsparky replied to Grant Petty's discussion DIY catapult for 2.6m fixed-wing?
"Hi Grant We aim at 18-20m/s launch speed, slightly higher than your 15m/s as the aircraft are different, The 3G is based on initial acceleration not constant acceleration as that is impossible with a bungee or spring system and difficult to measuere…"
May 11
Grant Petty replied to Grant Petty's discussion DIY catapult for 2.6m fixed-wing?
"I'm not quite sure where the 3G comes from if my target airspeed is, say, 15 m/sec (about 30 knots).  In that case, a 1G acceleration should accomplish that over about 10 meters.   3G over 10 meters would give three times the…"
May 10

Moderator
Dwgsparky replied to Grant Petty's discussion DIY catapult for 2.6m fixed-wing?
"I see where you are going but even a 10 meter track would still need about a 3G acceleration, not exactly portable ! If you are going that way then I would seriously recommend using using a large stepper motor with a suitable gearbox and a…"
May 10
Grant Petty replied to Grant Petty's discussion DIY catapult for 2.6m fixed-wing?
"Very helpful information; thank you very much. I'll add that I had been thinking about a relatively long track so as to greatly reduce the required g-forces.  As a starting point, I believe a 10-meter track (still greatly reduced compared…"
May 10

Moderator
Dwgsparky replied to Grant Petty's discussion DIY catapult for 2.6m fixed-wing?
"Hi Grant We have been building and providing medium sized catapults at www.Air-Vision-Air.com for members and others for several years.  These are mainly for fixed wing and flying wing aircraft up to 6Kg ( Typical Skywalker X8) . our part…"
May 10
Grant Petty replied to Timothy's discussion Pixhawk 2.1 Throttle Calibration not working - motors wont spin need help! in the group Pixhawk 2 User Group
"Tim - It's the X8R! "
May 9
Grant Petty posted a discussion

DIY catapult for 2.6m fixed-wing?

I built a largish fixed-wing UAV (Hugin 2.6m, roughly 8 kg MTOW if I recall).  It's definitely too large to hand launch, and it needs a surprisingly long takeoff run (especially on grass) to get airborne and clear of trees etc.  This is fine when I have access to a private road or something that can be used as an airstrip, but when that's not available, things become…See More
May 9
Grant Petty replied to Timothy's discussion Pixhawk 2.1 Throttle Calibration not working - motors wont spin need help! in the group Pixhawk 2 User Group
"Looks like you're not getting anything from the RC receiver.  I had this problem recently too, but intermittently. Fortunately, I had a spare receiver laying around, and when I replaced it, the problem went away.  That led me to…"
May 9
Grant Petty posted a discussion

Is this new LiPo battery already dead on arrival?

Just unpacked a new 3s 1500mah LiPo I ordered from banggood.  It arrived a month or so ago, but I only now got around to using it.  I also got a second identical battery at the same time, which is fine.Upon hooking this one up to my B6AC charger, I was immediately informed that a cell was low (I think it was down to around 3.2V, the others were near 3.85) and the battery couldn't be charged.  I bootstrapped it by switching to NiMH mode for a bit (0.5A max current) and then the LiPo charge mode…See More
Apr 25

Profile Information

About Me:
Newcomer to fixed-wing UAV.
Please tell us a bit about your UAV interest
Interested in home-built/DYI fixed wing UAVs that can be used in college-level instruction and research.
Hometown:
Madison, WI

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