Model: 3-mo. old BCPP

Symptom: Normal takeoff & hover characteristics 1st 30 seconds of flight, whereafter head speed drops over the next 45 seconds or so to point where BCPP will only hover weakly a foot off the ground.

Detail:

1. Installed G90 which came right up no problem & performed well. After 10 minutes or so of marvelously stable hover & slow flight I did an unintentional backward sliding landing i.e. it was sliding on the stock skids (guess I was a little too distracted by the G90's nice performance!), which would have been of little consequence except it grazed a metal garage door & destroyed the woodies. Also a few consecutive teeth on main gear looked ragged.

2. Replaced main gear/shaft (nothing I haven't done before).

3. Balanced, installed & tracked replacement woodie syms (again, nothing I haven't done before). Topped off the stock Li-Po while repairs were underway.

4. Fired up & lifted off normally.

5. After about the 1st 30 seconds of flight, the motor/head speed started reducing despite throttle advance @ Tx. Within the next 30-45 seconds head speed was so slow as to prevent lift more than a foot off the ground.

6. Replaced main stock motor with a spare new stock motor (I had already replaced the tail motor 2 weeks earlier as part of gen'l PM). Topped off stock Li-Po.

7. Fired up, same symptom.

8. Disconnected G90, reconnected stock gyro. Topped off stock Li-Po.

9. Fired up, same symptom.

10. Re-confirmed the symptom with my alternate stock Li-Po (about 3 weks old).

Doesn't seem like a radio problem, so:

Possible Cause(s)?:

A. A failing ESC in the stock 3-in-1.

B. Less likely, failing main shaft bearings.

C. Even less likely, my stock charger, despite its outwardly normal behavior, is no longer charging the Li-Po's to capacity even though it says it is.

Have scoured this forum for a few weeks & don't recall seeing this addressed.

I'm a long way from going brushless, Spektrum, etc. & don't really want to upgrade (yet) anything more than the G90.

Q1: Any of you BCP/P operators experienced anything similar &, if so, how did you resolve?
Q2: If A., above, is this my chance to replace the 3-in-1 w/a standalone ESC?

BTW, I've derived more downright-obsessive enjoyment from this flying machine than I can pen. I'm committed to its care and feeding and w-i-l-l see it develop to its highest potential. Uh oh, am I a father again?

Thank you in advance for reading this long post.

try changing out the tail motor any way, I had this proband changing th motors fixed it for 1 out of my 3 lipos. The other two just would not fly any more and the were almost new. Do you have a lipo monitor? If not get one I use this one http://tcdynamics.com/prod01.htm

thx zenchal 26. will try a lipo known to be properly operational. will also swap out the tail motor again (couldn't hurt no matter what, eh?) the lipo monitor looks promising w/the inflight wide-angle led. and they take paypal!

Have a read [link=http://www.rcgroups.com/forums/showthread.php?t=571321]HERE[/link]

I'm currently using a brushless setup with the exact same 4-1 and all my problems went away.

Would you by any chance be flying outdoors, I have noticed with my blade cp and 4 in 1 that as soon as things (4 in 1) cool down (about 5degrees C outside) the power drops and the helecopter begins to wobble and eventually becomes to difficult to fly or hover. If I bring it inside and run it, it recovers in about 20 to 30 seconds back to normal operation.
I know your first thought would be the lipo's cooling down and that the power is dropping off, but this does not seem to be the case as the battery remains warm to the touch. I have much experience flying planes outdoor in the winter using lipo's so I am sure this is not a result of the battery cooling down.
I think it might be something to do with the electronics inside the 4 in 1???

zenchal26: swapped out tail motor this morning with one known to be good - same result. However, thx again for your suggestion; had hoped it would fix!

will1563: ambient outdoor temp @ flight time is around 80 deg F. The batts do get warm. I swapped out the stock 3-in-1 this morning with a new one - same result. Am skeptical that both my stock lipo's would suffer identical malfunctions @ the exact same time but that now places the stock charger under suspicion. I need to get to my neighbor who's got a voltmeter. We can, at least, check the no-load voltage of freshly charged batts. My son also has a BCPP but I'll wait have to wait until he comes over to swap a few things with his rig
& see if I can isolate the prob. My thanks for your response.

mochaboy: before this little problem the BCPP would ascend like a rocket with stock woodie flats or syms using my stock lipo's. The only weight I added was the 9g G90. On the G90's maiden flights I could tell virtually no difference in the model's ability to hover for a long period or climb vertically (although my 'climbs' are exceedingly puny). Going brushless sounds inviting and I'm rolling it around in the back of my head. Sounds like you did the right thing in your conversion. But being the stubborn old f--t that I am, the BCPP has thrown down the guantlet and now I'll not rest until I find the answer. When that happens, I'll revisit your link & study like a book. I do appreciate your suggestions and thank you for them.

checked batt output with a 12v automotive taillight bulb. It illuminated brightly, suggesting that the batts are initially putting out close to 12v. that seems to eliminate the charger as a point of failure.

ValVista...Lipos not being under load will give false reading. You should always measure under load for true voltage. I had the problem with lifting and changed the main motor and my problem went away. Heli flies great.

My configuration:

HB CP2
Dual tail
EF Micro Gyro (similar to G90, but lighter)
SuperSkids
Seperate rx

It looks like you have checked everything. So these are just a shot in the dark:

1) A light test is not enough to actually test voltage there would not be a significant difference between 11.1 (fully drained) and 12.6 (fully charged). Get a voltmeter, or a decent charger that shows voltage, I use the 109.

2) You did not mention what you set your low throttle pitch to (3-5 degees). The reason I ask this is that it appears your motor is bogging, too much pitch could do it.

3) Make sure your pinon to gear is not too tight. There should be a little play in it. Feel the ease that you can turn your head assembly and add grease as needed.

4) Check for a bent spindle. (This does not sound symptimatic, but after a good crash, check it)

Good Luck.

lwatson 10-4, I will check that voltage with a meter as soon as i can lay my hands on one

here's what i accomplished with no improvement:

1. charged both lipo's with my charger. ran them both on another bccp & got 15 minute flights each. that suggests lipo's and charger are ok.
2. replaced 3-in-1
3. replaced main motor
4. replaced tail motor
5. replaced main shaft/gear
6. replaced spindle
7. tried another bccp tx

as for throttle trim, i've always run it @ midpoint & got 12-15 minute flight times
verified pitch = 0 deg in in idle up w/throttle centered
tried flying w/trim @ bottom, no improvement
main bearings run cool, power off spindown times haven't shortened, main gear runs fairly quiet & is surprisingly concentric to the shaft

what was a well-trimmed flier has become an instant enigma. i'm out of ideas and will shelf the whole thing indefinitely. it was a fun 3 months (the bccp was my 1st helicopter) and for 10 glorious minutes i watched the G90 do its thing.

many thanks for shooting in the dark; maybe a light will go on eventually !

Val,

The only thing I didn't try was a Team Orion Slo-Max 300 motor in there...I want to know the answer as badly as you do, but at the time, I was more interested in getting the d@mn thing flying. I've since moved on to a MaxiR and just wrote off the BCP as a "git 'round-tuit" project.

The only consistent factors in all my tests were time and heat, I just never did find out exactly what was going on - we tossed around a lot of great theories, but in the end, all I wanted to do was fly and was willing to throw any amount of money at it (foolishly I might add) towards that end.

Mochaboy

I re-read your link this morning in a slightly more subjective state of mind. Based on its contents and the 2 paragraphs in your previous post, I conclude that you know precisely where I'm coming from.

Thank you for paraphrasing it.

In 3 months with the CP Pro I've gone from rank beginner to steady hover & mild FF on a model reputed by some to be one of the most difficult for a beginner to grasp. It was a time of great concentration & tight focus; I've never had such a great, challenging & satisfying time on a hobby activity in my life. Total immersion.

At the proper time, I will resume the hunt for a solution, knowing that my BCPP isn't haunted, just showing its devlish side. I'm not advanced enough to go outside the mainstream e.g. brushless; am not even close to pushing the BCPP's envelope. I w-i-l-l 'git round-tuit'.

BTW I checked out a MaxiR site. Impressive (21 ball bearings? nice)

Am getting off-topic here w/nothing more constructive.

Again, my thanks to all responders.

And good luck, Mocha.

Closure.

I thoughtlessly laid down the new spindle with an older one & installed an old one, known to be defective. Things can roll around the bench & get out of control.

Accidentally discovered the new one, which I had intended to install, in a faraway corner of the bench.

Installed it & all's well.

This, and the combo of new parts listed above, have lent new life to the BCPP.

All advice was good & contributed to its revival.

Thx again.

End of Thread

Wait, you can't just let it go there. What was wrong with the spindle? was it simply bent, or tight?

The spindle I mistakenly installed was slightly bent in 2 places (a shallow 'Z' bend). It evidently introduced enough friction into the collective mix to continue bogging down the main motor. When I installed the correct, straight spindle, the motor resumed normal operation.

Also, I checked pitch again & reduced by another degree or so @ the pitch links. Head speed is now brisk w/woodie syms & ascends like a missile @ liftoff if I goose it even a little.

And, last but not least, the little tail motor rears its head one more time. The G90 was definitely doing its deed but tail performance was occasionally erratic & would zip a 90 deg CCW rotation w/o warning. Right rudder input would rotate the model another 90 deg CCW, resulting in a BCPP looking me in the eye & wondering where to go next! I'm not really ready for nose-in yet so would do a quick controlled setdown.

Suspecting sundry weirdness in the tail motor (only about 3 weeks old), I re-installed the original tail motor just for grins. I had replaced it simply as part of routine PM (due diligence, you know?). That cured almost the last of the quirky behavior & am flying it well w/G90 HH about 30%.

The only remaining oddity is, when flying HH, tail rotor spins rapidly (momentarily) when I advance throttle stick from full-off, ground looping the model nearly 90 deg CW. I get around it by starting throttle with some left rudder, then centering & lifting off. At that point, the tail rotor spins up quickly as the G90 attempts to maintain heading. From there it's business as usual.

If that's all I have to worry about now, I'm one happy camper as I practice transitional side-ins.

BTW lwatson your point #4 turned out to be well-taken. Not only did the backward 'landing' do a number on the spindle but evidently did some internal damage to the new tail motor as well. I'll lay in a supply of them; still want to stay mainstream parts-wise until I'm a solid 2D flyer.

zenchal you were on the right track after all w/your tail motor suggestion. Turns out, despite its young age, to have been one of the problems after all. I just never had one fail & was unsure what to look for.