Pieliker96
Elite member
This is the last update before the maiden flight.
Batteries
These are pretty good. They give a good 7% more static thrust than previous (now 3.75kg) for a 6% increase in all-up weight. I'll have more capacity than previous as well, which allows more flight time margin.
Retract Woes
This is what I get for being cheap and not designing an easily accessable nose retract.
I had trouble getting the nose gear to lock down properly, it would collapse under braking load due to the trunnion slipping past the slider. I had to cut into the fuselage, unscrew the retract, and repair it while it was hanging there as the servo connector was deep inside the fuse on the other side of a very small hole. I managed to get it to work properly by adding heatshrink to the little tab that contacts the limit switches - this got it to the right place to lock the gear and seemed to fix it. On the next taxi test, the same issue cropped up on the mains, which recieved the same modification - one board died and had to be replaced in the process. When the mains were repaired, the nose stopped working due to a broken limit switch, which was then replaced with a spare. It worked for a while after that and then died again.
I'm keeping them locked in the down position for the maiden flight. I'll have to find a better nose gear and retrofit it for future flights.
Taxi Test Results
See the build video log below at 4:33. With the gear in a stable configuration, it performed admirably. The turning radius in high rates is quite a lot better than previous. Braking action was rather anemic at first and was subsequently improved by shortening the brake linkage (increasing tension) and reapplying hot glue to the braking surfaces. The nose gear mount survived braking at moderate speed and seems plenty strong. Any slop I notice from loading the nose gear is due to the retract unit itself, not the mounting. I may need to reduce braking pressure a tad as one of the nose wheels showed small patches where it was skidding. There was very little change in directional stability when the brakes were applied. I attribute this to toe-in on the main gear, the fact that the braking force is rather smooth and relatively small in magnitude, and the high moment of inertia around the craft's yaw axis.
Last Video Log
More Full-Sized Photos
-------------------- XB-70 V2: More Power, More Lift, More Engineering. --------------------
Batteries
These are pretty good. They give a good 7% more static thrust than previous (now 3.75kg) for a 6% increase in all-up weight. I'll have more capacity than previous as well, which allows more flight time margin.
Retract Woes
This is what I get for being cheap and not designing an easily accessable nose retract.
I had trouble getting the nose gear to lock down properly, it would collapse under braking load due to the trunnion slipping past the slider. I had to cut into the fuselage, unscrew the retract, and repair it while it was hanging there as the servo connector was deep inside the fuse on the other side of a very small hole. I managed to get it to work properly by adding heatshrink to the little tab that contacts the limit switches - this got it to the right place to lock the gear and seemed to fix it. On the next taxi test, the same issue cropped up on the mains, which recieved the same modification - one board died and had to be replaced in the process. When the mains were repaired, the nose stopped working due to a broken limit switch, which was then replaced with a spare. It worked for a while after that and then died again.
I'm keeping them locked in the down position for the maiden flight. I'll have to find a better nose gear and retrofit it for future flights.
Taxi Test Results
See the build video log below at 4:33. With the gear in a stable configuration, it performed admirably. The turning radius in high rates is quite a lot better than previous. Braking action was rather anemic at first and was subsequently improved by shortening the brake linkage (increasing tension) and reapplying hot glue to the braking surfaces. The nose gear mount survived braking at moderate speed and seems plenty strong. Any slop I notice from loading the nose gear is due to the retract unit itself, not the mounting. I may need to reduce braking pressure a tad as one of the nose wheels showed small patches where it was skidding. There was very little change in directional stability when the brakes were applied. I attribute this to toe-in on the main gear, the fact that the braking force is rather smooth and relatively small in magnitude, and the high moment of inertia around the craft's yaw axis.
Last Video Log
More Full-Sized Photos
-------------------- XB-70 V2: More Power, More Lift, More Engineering. --------------------
Last edited:
