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Old Nov 16, 2011, 08:30 AM
OOPS
Manta1's Avatar
USA, GA, Cochran
Joined Jun 2008
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Lol thread blowup number 23456777 over crazy stuff. Good thing we aren't all married to one another.
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Old Nov 16, 2011, 08:31 AM
Sippin the Koolaid!
losifanatic's Avatar
United States, NC, Hertford
Joined Oct 2007
16,466 Posts
Birk thats normally true with smaller props but when I switched from apce to xoar (18x8) I got more low end puch. The apce flexed WAY to much. Then going to a mejzlik cf prop I got even more power down low and more punch.
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Old Nov 16, 2011, 08:33 AM
Team CAPACITY
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United States, IN, Osceola
Joined Feb 2008
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I don't even want to write this post. I woke up this morning sick thinking about it. But here goes.


I flew the 71 3 more times last night for a grand total of 6 flights in two days. I love this plane.

Well on flight 6, I came down in a 3/4 speed blender rolled over and pulled into an elevator to bring it down on the deck for an upright harrier. When it got low I powered up to give forward flight. NOTHING. uh oh. No power. The motor won't spin. Elevator to tera firma. Landing gear folded and destroyed the LG area of the plane. Destroyed it. Not even so much as a scratch anywhere else. Looks like I get to do my first complete MB replacement.

after getting it home and expecting it closer I found a bullet connecter on the esc/motor had come unplugged in flight. I could shoot myself!

The battery tray goes all the way back to the rudder servo. You think I could just splice old with new directly over top the two LG formers? That way the weak spot is actually in the middle of the strongest point.

Here are some photos of the sequence of events thus far.
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Old Nov 16, 2011, 08:36 AM
Sippin the Koolaid!
losifanatic's Avatar
United States, NC, Hertford
Joined Oct 2007
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That makes me sick just looking at it. Sorry to see that. That why I started direct soldering.
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Old Nov 16, 2011, 08:39 AM
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Bridgeton, NJ
Joined Mar 2009
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Originally Posted by 94'325is View Post
I have an 8S setup and run an 1800 mAH 6.6V LIFe Rx pack on my Slick. It's great because my servos see 6 Volts of power and I have had a situation where the main packs departed and I was able to glide the plane down safely. Also the extra pack is nice because it's one more way to get the CG dialed in where you want it.
If it's a 6.6V pack how do the servos see 6V? Regulator or UBEC? Otherwise they will see over 7 volts when topped off. Many servos will be fine with this voltage and many won't and will burn out prematurely. What are your servos rated for?

I went down the external battery pack route to try it but went back to UBEC off my main batteries on my electrics. Ended up with same or longer flight times, less weight and less overall hassle. On bigger planes I run a dual radio setup each fed by it's own UBEC so I feel quite comfortable with the redundancy I have. The 2 radios and two UBECS is yet another way to configure 70x and larger birds that I don't think have been discussed here recently. Just throwing that out.

Carlo
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Old Nov 16, 2011, 08:42 AM
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United States, IN, Osceola
Joined Feb 2008
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Originally Posted by losifanatic View Post
That makes me sick just looking at it. Sorry to see that. That why I started direct soldering.
The worst feeling in this hobby is to watch a brand new plane go in. I still feel naucious even thinking about it. I'm hoping I can splice the old with the new and have a good strong plane when its done. I've only ever had to replace a firewall never a LG bay.

PD
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Old Nov 16, 2011, 08:55 AM
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Florida
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Ouch man, that stinks to see. On the good side it does look repairable, you may have to let it sit for a few days for the sting to go away but it is fixable.

Another plus is that you were able to see how great it flies so you can use that as motivation to get it back in the air!
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Old Nov 16, 2011, 09:01 AM
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Florida
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Originally Posted by cayars View Post
If it's a 6.6V pack how do the servos see 6V? Regulator or UBEC? Otherwise they will see over 7 volts when topped off. Many servos will be fine with this voltage and many won't and will burn out prematurely. What are your servos rated for?

I went down the external battery pack route to try it but went back to UBEC off my main batteries on my electrics. Ended up with same or longer flight times, less weight and less overall hassle. On bigger planes I run a dual radio setup each fed by it's own UBEC so I feel quite comfortable with the redundancy I have. The 2 radios and two UBECS is yet another way to configure 70x and larger birds that I don't think have been discussed here recently. Just throwing that out.

Carlo
They're briefly at over 7 Volts but the pack settles down to mid 6V range. I've run a LiFe packs on Hi-Tic, Spektrum/JR and Futaba servos and so far have never had an issue. It's the upper limit of the Voltage they'll take but I've emailed Hi-Tec about it and they say that it's perfectly acceptable, just don't push them any higher unless it's a HV servo.

Dual radios is a great idea, but for me on this size plane I'm more in favor of running a separate LiFe pack as my personal experience has been great and I have a multi-port charger so charging the Rx pack w/ flight batteries works great.

There's a lot of different setups that all have their merits, experimenting, research and asking questions will point you to the right setup for you.
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Old Nov 16, 2011, 09:10 AM
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Bridgeton, NJ
Joined Mar 2009
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I went the dual radio method since I used to do this on bigger planes. It's not really as good on the 71s/72s however since we only use one rudder and one elevator servo. On a bigger plane with multiple servos it's a piece of cake as you can setup the left side on one radio and the right side on the other radio.

I've thought about adding another elevator servo for piece of mind but haven't gotten around to it. Definitely overkill on 7x size planes but worth considering on the 8x size planes. Also by running dual radios you can usually get away from power boxes and stuff like that a little easier.
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Old Nov 16, 2011, 09:13 AM
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United States, LA, Moss Bluff
Joined Nov 2008
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Quote:
Originally Posted by pstrdenver View Post
I don't even want to write this post. I woke up this morning sick thinking about it. But here goes.


I flew the 71 3 more times last night for a grand total of 6 flights in two days. I love this plane.

Well on flight 6, I came down in a 3/4 speed blender rolled over and pulled into an elevator to bring it down on the deck for an upright harrier. When it got low I powered up to give forward flight. NOTHING. uh oh. No power. The motor won't spin. Elevator to tera firma. Landing gear folded and destroyed the LG area of the plane. Destroyed it. Not even so much as a scratch anywhere else. Looks like I get to do my first complete MB replacement.

after getting it home and expecting it closer I found a bullet connecter on the esc/motor had come unplugged in flight. I could shoot myself!

The battery tray goes all the way back to the rudder servo. You think I could just splice old with new directly over top the two LG formers? That way the weak spot is actually in the middle of the strongest point.

Here are some photos of the sequence of events thus far.
Bummer, hate to see it.

I would not try and splice, just a little more debonder to get the complete battery tray out. Just to say, don't try and splice before the wing tube. That tube ties the outside fuse and MB all together.

For a 71 yours doesn't look to bad, looks like most of the sides are intact. Might try not removing the covering on the sides, just cut the bottom back.
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Old Nov 16, 2011, 09:40 AM
Team CAPACITY
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United States, IN, Osceola
Joined Feb 2008
1,361 Posts
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Originally Posted by robj View Post
Bummer, hate to see it.

I would not try and splice, just a little more debonder to get the complete battery tray out. Just to say, don't try and splice before the wing tube. That tube ties the outside fuse and MB all together.

For a 71 yours doesn't look to bad, looks like most of the sides are intact. Might try not removing the covering on the sides, just cut the bottom back.
Yeah, I've gone this far, might as well tear it all out. Thanks for the advice.

PD
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Old Nov 16, 2011, 11:04 AM
iumop ap!sdn w,I
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Joined May 2005
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Quote:
Originally Posted by Manta1 View Post
Lol thread blowup number 23456777 over crazy stuff. Good thing we aren't all married to one another.
At least I know what a bec is now.

Quote:
Originally Posted by pstrdenver View Post
Yeah, I've gone this far, might as well tear it all out. Thanks for the advice.

PD
That's nothing. You'll be amazed at how fast it starts to go back together. Just don't remove too much stuff until you see what comes in your motor box kit. They all seem to be a little different (unless things have changed).
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Old Nov 16, 2011, 12:40 PM
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Belarus, Vitebsk province, Vitebsk
Joined Oct 2011
24 Posts
Hi guys,
Is this setup ok?
- 2x4 Gens 5300 30c
- CC PI 120HV2 (or 80HV2 should be enough?)
- Motrolfly Dm5320-300
- 19x8 meijlik prop.
- 4x7954SH
Сan't decide whether to use BEC Pro with the main pack or use Separate 2s 1300-1500 with direct connection
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Old Nov 16, 2011, 12:55 PM
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robj's Avatar
United States, LA, Moss Bluff
Joined Nov 2008
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Quote:
Originally Posted by octopuss View Post
Hi guys,
Is this setup ok?
- 2x4 Gens 5300 30c
- CC PI 120HV2 (or 80HV2 should be enough?)
- Motrolfly Dm5320-300
- 19x8 meijlik prop.
- 4x7954SH
Сan't decide whether to use BEC Pro with the main pack or use Separate 2s 1300-1500 with direct connection
You can run lighter batterys, I run 3600, 3800, 4000(hyperions, pretty light). 80a will do you as you shouldn't be pulling over 70a on a 8s. Ice 100 might be cheaper. $108 on amazon.

Check that...$104 shipped.
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Old Nov 16, 2011, 01:07 PM
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cayars's Avatar
Bridgeton, NJ
Joined Mar 2009
2,083 Posts
Quote:
Originally Posted by octopuss View Post
Hi guys,
Is this setup ok?
- 2x4 Gens 5300 30c
- CC PI 120HV2 (or 80HV2 should be enough?)
- Motrolfly Dm5320-300
- 19x8 meijlik prop.
- 4x7954SH
Сan't decide whether to use BEC Pro with the main pack or use Separate 2s 1300-1500 with direct connection
Why such a large motor? 4325-280 or 300 would be better for that size prop. You can also drop down to 4000 size packs although there is plenty of room for two 5300s but you might like it lighter.
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