PBX X-Box flyer with VTOL feet
03-17-2005, 10:51 PM
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PBX X-Box flyer with VTOL feet
Hi guys
I don't know if there are any former PBX (X-wing) builders still hanging out in the forum, but I wanted to solicit some advice. I just finished building a double Pizza Box X-wing with carbon legs in an attempt to have a complete VTOL flight. The base of legs extends about 40". I just flew it tonight and dumped it into the ground 4 different times. Luckily the pasture was soft and I only broke rigging wires.
I wanted to know if any of you had played around with thrust angles on these things. When it's sitting ready for takeoff, I apply power and it pulls the nose up and to the right. The only successful flight was with a hand launch. I landed it by basically flying it into the ground while attempting a stationiary hover. It's very nerve racking to fly but seemed to do OK in level flight. I am wanted to experiment with CG and possibly thrust angles to get a more stable hover. My particular unit is powered with an OS 46 FX so it had plenty of vertical power. The weight is 3lb 10 oz and the current CG is about 6.25" back from the leading edge.
Any advice is appreciated
Thx
Darin
I don't know if there are any former PBX (X-wing) builders still hanging out in the forum, but I wanted to solicit some advice. I just finished building a double Pizza Box X-wing with carbon legs in an attempt to have a complete VTOL flight. The base of legs extends about 40". I just flew it tonight and dumped it into the ground 4 different times. Luckily the pasture was soft and I only broke rigging wires.
I wanted to know if any of you had played around with thrust angles on these things. When it's sitting ready for takeoff, I apply power and it pulls the nose up and to the right. The only successful flight was with a hand launch. I landed it by basically flying it into the ground while attempting a stationiary hover. It's very nerve racking to fly but seemed to do OK in level flight. I am wanted to experiment with CG and possibly thrust angles to get a more stable hover. My particular unit is powered with an OS 46 FX so it had plenty of vertical power. The weight is 3lb 10 oz and the current CG is about 6.25" back from the leading edge.
Any advice is appreciated
Thx
Darin
04-04-2005, 10:02 PM
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RE: PBX X-Box flyer with VTOL feet
Darin I built the first PBX-Wing with Ken Hux election signs. It was a lot of fun but not very stable. The one thing I had though was four small flaps near the leading edge behind the prop that moved with the ailerons for anti-torque control. It's not very stable near the ground because the high speed thrust from the prop blows the tail around as you get close to the ground. I think your CG at 6.25" on the 24" chord is ok but you could go forward 1/2" and it would help with high speed flight, especially in the rudder inputs. I later on made an X-Ball with two 24" discs that had a wing leveling gyro on the ailerons. This is a 2-servo aileron gyro sold by Hobbico. This was able to counter the torque without the anti-torque flaps on the PBX-Wing. In fact with the gyro on the ailerons it was much more stable all around. I think that a much larger diameter prop is needed, turning much slower. Maybe a properly geared electric motor/prop combo optimized for static thrust?
Do your VTOL feet have wheels at the tips? It's hard to see in the photo. Castering wheels would probably be best, and land on smooth pavement so it can slide a little. I never got a single landing where it stayed vertical but I got real close and I think it's certainly doable, especially with the gear you have on there. One thing I found about the pizza boxes is that trimming off the front corners at 45 deg angles really smooths out the machine overall. A half circle, half square pizza box seems to be optimal.
-Tom
Do your VTOL feet have wheels at the tips? It's hard to see in the photo. Castering wheels would probably be best, and land on smooth pavement so it can slide a little. I never got a single landing where it stayed vertical but I got real close and I think it's certainly doable, especially with the gear you have on there. One thing I found about the pizza boxes is that trimming off the front corners at 45 deg angles really smooths out the machine overall. A half circle, half square pizza box seems to be optimal.
-Tom
04-04-2005, 11:45 PM
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RE: PBX X-Box flyer with VTOL feet
Hey Tom,
I remeber the Ken Hux craft.
My hovercraft had packing foam material at the ends of the carbon landing legs. Castering wheels might be weight prohibitive. The gyro may be my next experiment. I would like to get a complete VTOL flight with this thing before I destroy it ! It seems to be pretty sturdy when flown (crashed) around deep grass. What's funny is I can hover 40% aircraft all day long and this is way more difficult.
Best regards
Darin
I remeber the Ken Hux craft.
My hovercraft had packing foam material at the ends of the carbon landing legs. Castering wheels might be weight prohibitive. The gyro may be my next experiment. I would like to get a complete VTOL flight with this thing before I destroy it ! It seems to be pretty sturdy when flown (crashed) around deep grass. What's funny is I can hover 40% aircraft all day long and this is way more difficult.
Best regards
Darin
