The flying monkeys got me...

Helis and fixed wing

AMA 957918
IRCHA 4345
AMA Intro Pilot Instructor

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.
 

4 comments :

  1. I didn't think you can 3D a Flybar? I thought you had to have a Collective Pitch (CP) Flybarless Heli for 3D?

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  2. Actually you can! But I think you are recognizing something else. There are the CCPM helis, collective pitch where the pitch of the individual blades can be changed dynamically,, which include fly barred and flybarless helis. The other class of simpler helis a the FIXED PITCH helis. It is the fixed pitch heli, one whose blades do not change pitch, in which 3D isn't possible. 3D can be flown with any CCPM heli with the power and setup required. Hope this helps!

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  3. Got it know! I think I might have know that, but the terminology think is my biggest learning curve. Been playing with a very cheaply made coaxial flybar heli and made the huge jump to a Walkera Mini CP. I don't think 3D will be in my future anytime soon, but I did buy the training wheels (training bars). I think the 3-Axis Gyro should be a great help with the learning curve!

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  4. Sounds like you got the bug! Check www.helifreak.com

    ReplyDelete