Flight page 1
5/24/06 - Got everything out to the club field today and ran a taxi test and it was successful. It ran right down the run way nice and straight with plenty of power and speed. The brake works but the wheel has to be on the ground. I have to move the brake to a switch so I can work the elevator while hitting the brake.
Ran full throttle for 4 min. and the motors and batteries were not hot at all. I didn't get a temperature but I would guess the motors were around 100F and the batteries around 110F.
Old Iron Sides Flies again!
6/5/06 - Today was the day. I met Ken Busse, President of EBRC in Livermore at their club field at 9:00am. It was cold (in Livermore in June?) from the San Francisco fog and the wind was blowing but blowing right down the runway. I assembled the B-24 and also my P-47 while hoping the wind wouldn't change to a crosswind. After a flight with the P-47 to get used to the field, I was ready. The wind was being kind so I pointed it down the runway and throttled up to full throttle -around 8900 rpm. It took off in about 200' and went up like a homesick angel. After putting the gear up I realized that it was flying perfect without any trim changes neccessary.Wow! That's what builders dream about! So there it was, finally in the air and working as planned, right down until the landing. I flew around for 5 min. getting a feel for it. I got up real high, slowed down and dropped the flaps-nothing,more flaps-nothing, full flaps and still did not notice any pitching or rolling,nice! I throttled way back while in full flaps to see what it would do and it just did a little sink, nothing unwanted or unpredictable. I throttled back up and raised the flaps and flew around some more at half throttle, about 5000 rpm. I did throttle up in the turns, I didn't want to have it drop out of the turn. My timer went off so it was time to land, the problem was I didn't tell anyone I was landing. My friend Kevin was on the runway getting pictures of what he thought was a slow fly by. He got off the runway, I landed on the runway and we were good until the nose came down with a thud- no nose wheel, I didn't notice that. So it ground to a halt with that undignified chin to the pavement. The good thing was that it wasn't pavement but a plastic mesh. There was no damage except to the chin window which got knocked loose when it hit one of the large nail heads that hold down the plastic mesh, and there's a black mark on the chin window from the plastic mesh. I'm glad it happened here. My home field is pavement. The nose gear got caught up on the steering cable. That will not happen again! . I didn't use any flaps on landing. There was about a 10 mph headwind and it settled right in for soft touchdown before grinding to a halt.
It didn't feel heavy, didn't feel super light either, it just felt good, just right. It tracked well and handled a steep bank turn very well. If this thing was 16 lbs as Palmer predicted it would be a floater and would be real fun to fly in any wind. As it is at 20 lbs. it is still a joy to fly. My hat's off to Palmer, the designer. Yes his plans need to be updated and modernized with CAD but the design flies and flies very well . Yes it could and should be lighter. The rear fuselage formers don't need to be plywood. I could also save some weight by going to smaller batteries, lightening the tail turret, going to a smaller air tank and fitting it into the front, moving the tail servos forward of the CG, I will do some these things in the future so it can loose some of the dead weight it's carrying around.
So it's real good to get that out of the way! First flights are always nerve racking but especially so when you've got this much time invested. I feel pretty good about it. It will take a few more flights to say I'm comfortable but I would say it's very easy to fly and flies beautifully!. Absolutely no problem at 20 lbs. I think I could carry a few pounds of bombs! Fake ones of course!
After the flight I ran the motors on the ground like it was flying, half throttle with occasional 3/4 or full throttle runs to simulate a turn, takeoff or touch & go. I got an additional 12 minutes of motor run before noticing any power drop. And all four dropped the at the same time. And I think I could have still flown to a landing at the reduced power.
I can say that going electric was the best decision I made on this project. It's real nice to not worry about an engine out. We did determine that maybe I over batteried this thing. I could have easily used some 15C discharge, 2100mah packs and reduced the weight at the same time. As it is I can easily get two 6 minute flights off one charge and have power to spare.
Some of the specs of the first flight-
Takeoff weight - 20lbs
prop used 10/8 Zinger (wood, 2 blade)
Motor -AXI 2820/12
ESC - Castle Creations Phoenix 45
Battery - Poly Quest 3s 4000 mAh
Airborne time - 5.5 minutes
Takeoff RPM - Approximately 9000
Cruise RPM - Approximately 5000
Power used - Approximately 1/3 of the pack
Takeoff Amps/Watts - Approximately 27/270
Cruise amps/watts to be determined on further tests
Temperature - 65F
Wind - 10 mph
6/16/06 -Flew for the second time today
Today I flew at my home field, Bayside RC in Fremont, CA. It was hot, 90°, with a very slight crosswind. It took off in about 160' , flew very well for 5 min. and dropped dropped the gear, dropped full flaps - 30° and brought her in with no problems except for a late touchdown and brakes that don't work as good as I hoped. It's not easy to stop 20lbs. with one 3" tire. I only flew once. I'm still trying to get a feel for how long I can fly and can I get two flights of one charge. Also at this point, to build up confidence, I like to fly once and then look it over carefully before flying again. Like the first flight, this flight had a few wrinkles that need to be ironed out.
Recharged the batteries -
#1 took in 2.23 Ah
#2 took in 1.93 Ah
#3 took in 2.21 Ah
#4 took in 2.06 Ah
This shows that I used about half the battery capacity for a 5 maybe 6 minutes. I did feel that I used more throttle this flight. I don't think I'm ready to do two flights on one charge. I most likely just do a longer flight and recharge. I bought a second AF109 charger and they claim I can charge two packs at a time. I haven't tried it yet.
A few things needed fixing after the flight;
- I broke off part of the main gear mount access hatch while installing the batteries
- The right gear support strut broke.
- The tail skid hinge detached from the fuselage. That and probably the strut brake happened when rolled off the end of the runway.
- The outer supercharger/battery hatches don't stay on unless the batteries are in just right. One fell off while taxiing and the other fell off on the takeoff. I retrieved both.
The good news is the nose gear worked flawlessly.