The flying monkeys got me...

Helis and fixed wing

AMA 957918
IRCHA 4345
AMA Intro Pilot Instructor

Saturday, September 29, 2012

Flight Mode and Hold are not compatible

Whodda thunk? My beloved HK 500 died a miserable pilot induced death today. My favorite helicopter ever... I betrayed her today. So this is how it went down.
 
Lift off, hover, looks good, hit flight mode a couple of feet AGL. Wha'? POWER LOSS, tail drops, I compensate but over do it trying to auto and a blade strikes. It was over in seconds. 6S is a whole lot of power and she pretzeled something fierce. I was in shock. It was clear she went into hold becasue that's what happens when you hit the hold switch. As I thought about it I realized I had hit Hold and Flight Mode (opposite sides, same switch position index finger tip) and when she didn't spin up but instead spun down, my inexperience and lack of focus failed me and I flew her into the ground. Right now it looks like blades, tail boom, canopy paint cracked and chipped, missing tail boom support rod, split the landing gear (tube is fine), snapped a servo arm, but the servos seem fine. I will be surprised if there isn't something else broken... like my heart. Well, tomorrow morning I will start on her rebuild.
 
I have everything I need to rebuild the HDX 500, but am not looking forward to the labor of taking it completely apart to replace the frames. I love that old heli, so I am sure it will be next on my list.
 
I took the EXI 450 Sport out, and for some frickin' reason her tail belt is binding. Plan to take the tail apart and figure that out tonight, if I can find the energy.
 
Lastly, I flew the ill fated Sbach. I flew her with a 3S and she seemed anemic... she was twitchy on 20% rates, but once I got her trimmed she flew pretty well. She had a strong tendency to dive despite her CG being centered. Adapted. Powered off, she glided fair. I did a touch and go, seemed fine. I flew around a bit more and when I came back around on final I stalled her in a turn (she got rocky in the turn) and she landed belly down, stripping her gear, poked a whole in the wing, and that was it. Her gear are not well secured after multiple pairs, but still, it was a pretty abrupt landing. I fixed that this evening. They are held in with epoxy, no real wood to wood contact. This thing is almost ridiculous... Tomorrow I will fly her with a 4S, and try to remember to land her hot. More so because she will be heavier with the bigger battery. I honestly don't expect it to come out well.
 
At least I met some great guys today! Frank, Don and Jerry were there and made me feel welcomed. I need to work on learning how to line up with the paved runway, and to come down lightly as the runway is not as forgiving as grass. But then, it is sweet landing smooth instead of watching the grass try to pull the gear off. Add to this that I am not flying as much as I was, and my skills are way behind the plane. Practice...
 
It was not my best day of flying. I am having trouble adapting to my new field, all psychological. Working on it.
 
ADDENDUM (9/30/12): Oh, almost forgot. I also flew the PulseXT 25e. I had a problem keeping her steady on final, I think coming in too slow, and she would drop her nose and prop strike the ground. Went through a couple of props (12x8e), in fact the last couple I had. I also skinned the wing tip. So proud of myself.
 

Saturday, September 22, 2012

Insanity...

is doing the same thing over and over again, expecting different results. I think it was Albert Einstein who said that. Well, yeah, I'm insane. Just before I left Gulfport the Hobby King Sbach 1000mm crashed, not so bad, fixed pretty quick. It did its usual, a dive of death from on high. Its done it before, and in the week before I left, it did it again. It was crushed, the nose shoved in crushing the motor box and caving in the firewall, bending the motor shaft, badly folding the gear, and crushing the cowl itself, fracturing it in three places pretty severely, and badly damaging the fuse in several places. Since I was moving, I piled it together and let them ship the pieces you can see in the lower left corner of this pre-move pic.
 
Its been laying in my apartment, the body in the lab, the wings under my bed, shattered. A couple of weeks ago I started reworking the frame. I had to rebuild the fuselage behind the cowl, the underside and back behind the canopy, recote it, and rebuild the motor box and the firewall. That took a cuple of weeks of slow work. I then rebuilt the cowl, using epoxy and Bondo, and sanded it down to the fiberglass. It still has some imprefections. I primed and repainted it in a similar, if not exactly the same pattern as the original. It came out pretty well, if I do say so myself! I am worried she's added some weight though.
 
Today I finished her. I drilled the new cowl mounting holes, lined up the motor, and drilled the firewall support holes for it. I found the motor shaft bent on the HURC Power Up 15 motor. It was jammed solid in the outrunner and I ended up having to cut the shaft at the top of the outrunner, and pound the other end out with a hammer. Replaced the shaft, rebuilt the motor, and installed it. Put the wings on after fixing some cote damage (minor, from the crappy packing job the movers did). I had to take the AR500 from the Hangar 9 60 sized Sopwith I have museumed. I would prefer a AR600 so I could prgram flaperons, but its what I've got. It took me a while before I realized it was an AR500 and not an AR600... when I couldn't program the left aileron I realized it (the Aux slot is actually Aileron, and acts like a Y with the regular Aileron channel.
 
Last time she seemed to fly well with 3S batteries. The 4S batteries give a lot more power, but the weight penalty bogs her down and she flies heavy. I have no idea why she cannot come out off some dives. Many people have found this fatal flaw, so its something about the design. The first time it happened to me I put larger mini servos in for the elevator, but that hasn't made any difference. I still don't know why... I will always fly her aerobatics high from now on.
 
I wish I had taken pre pics of the cowl and fram damage. Here's the FINAL rebuild. FINAL. I MEAN IT. This week, possibly tomorrow weather permitting, I will find out if she will die one last time... but then she's sooo pretty...
 
 
 
 

Wednesday, September 12, 2012

POWER, SCOTTY! I NEED MORE POWER!

After work today I took my HK500, my HDX500, the EXI 450 Sport and the EXI 450 FBL out, along with the Stearman and the Cosmic Wind. I flew the Cosmic Wind first, and after a bit of tweaking trim, she flew great. The winds were picking up, so I flew the HK500. I tried two seperate packs of 6S (two 3S in series), and both went to low power shortly after takeoff. Both were fresh, and after a couple of minutes of hover they were down to around 3.7V per cell. Shortly after lift off you could hear her spin up to full power, lift off, then immediately the head speed dropped audibly. I landed her after but a minute and checked the voltage. These were almost full charge at takeoff, but down to 3.7V. I tried a 4S and she flew great, no power drop off. Later I tried a third and fourth 6S set and it flew perfectly. Not sure what that was all about. Will need to check those packs.
 
I set up the Stearman, and realized I had not plugged in the aileron servos on my post-move repairs. This is going to take removing the wing and fishing out the leads, putting the extensions on, and putting the whole thing back together. I set her down and put her away. I will deal with that when I get home.
 
I took the HDX500 up, and shortly after takeoff I noticed a sudden power loss, and she seemed to bend in the middle as she came down hard. Turns out she split her frame. I knew there were a couple of cracks, but had repaired them, and since I don't 3D and the rest of the stress points were fine, I didn't think it critical. Guess I was wrong...
 
She cracked through and through at the two repaired points, and all of the other weak points. These frames were the original and are over 5 years old, so I am not surprised. Flybar is bent, and she snapped the tail boom, tossing one of the boom supports to who-knows-where, but other than that she is intact. I debated if this was the time to replace her with another HK500, but its cheaper to buy new frames. So I ordered new ones from CNChelicopter, for about $17 a side, and new 500 class tail boom supports from Helidirect for $10. It will be laborious, taking apart the scrambled parts bolt by bolt, and then rebuilding the entire heli from scratch. Oh well... needed a good project. I am kinda fond of her...
 
I took up the EXI 450 FBL and she too lost power, not completely, and I was able to hover her down. She stripped a few teeth on the main drive gear on landing in the weeds, so that will need to be replaced. Not sure what was wrong, good battery. Will need to fix her and trouble shoot that too.
 
No longer optimisitic, I took the EXI 450 Sport up, and found out her tail boom was slipping back and forth, so she could not maintain her tail rotor headspeed. Grounded for repairs.
 
This sucked. Power issues...
 
Took the HK500 back up with another 6S pack and she screamed back and forth, circles, figure 8's, fun stuff! Its amazing the power difference between 4S and 6S. I don't 3D so I won't make another 6S, but wow, the power is stunning. I can only imagine what my Align Trex 600 will be like if I set her up 12S... Maybe I will just make her 8 or 10S? Naw... 12S! The wind had picked up a bit, and I didn't want to keep flying the HK500, so I decided to call it a day.
 
Tomorrow night is the Wingmasters meeting. I need to go to get a key for the electric power and learn how to turn it on. Bet you money the guy with the keys either doesn't show up, or doesn't bring the keys... I doubt I will fly, don't like flying in front of crowds of people I don't know.
 
Repairs on the Sbach 342 are underway. I had to repair and refinish the cowl, and painting it slowly. If it crashes again I will be done with her. I am looking at getting a 60 sized one... later.