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Oct 29, 2020, 04:48 PM
Registered User
janmb's Avatar
Quote:
Originally Posted by 4stripes
In that case the BB should be able to provide more current than someone who used a Y connector to power the two elevator servo leads.
At first glance, yes.
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Oct 29, 2020, 04:51 PM
Registered User
hklagges's Avatar
Quote:
Originally Posted by captain MoMo
What is amazing to me is that we are here solving a very big problem for MRC and Freewing and yet I have still not seen any communication or at least acknowledgement that they are working on it.
True≤! It is even more amazing if one considers that after a certain point in time, people will switch from solving the problem for them to being a problem for them.

Cheers,
Henrik
Oct 29, 2020, 04:51 PM
Foam addict
4stripes's Avatar
Is the BB connected with 3 wire leads from each receiver channel? So many connections should provide plenty of voltage.
Oct 29, 2020, 04:54 PM
Lee Liddle
Knife Liddle's Avatar
Quote:
Originally Posted by 4stripes
Is the BB connected with 3 wire leads from each receiver channel? So many connections should provide plenty of voltage.
Yes all of the wires from the rx to the bb are 3 wire extentions about 5" long. Good point.
Oct 29, 2020, 05:15 PM
Registered User
janmb's Avatar
Quote:
Originally Posted by 4stripes
Is the BB connected with 3 wire leads from each receiver channel? So many connections should provide plenty of voltage.
Yes.

Then again, keep in mind that the more functions we bypass the BB, the less wires remain to carry whatever load goes through it.

But I strongly doubt the BB is responsible at all, at least not in terms of voltage drops or similar. It has a fairly weak voltage tolerance, that much is well known and also confirmed from MRCs side, but I assume that has far more to do with onboard components rather than the IC load-bearing tracks.
Oct 29, 2020, 06:25 PM
low, left, & fast
nuts-n-volts's Avatar
Quote:
Originally Posted by captain MoMo
Sorry - which servo are you talking about? Make and model? Corona? Thanks.
ProModeler. I denoted the two I think would be good to go with. They will work on 5v but with a little less max torque. Mind you I'm working on getting the controls all operating at 8.4v as well. Yeah, might be overkill, but it's an experiment in the making. The thing with ProModeler servos is that there is practically no slop in the gear train. Solid, professional all the way thru.

Let me ask you, MoMo. Did you upgrade the elevator linkages to solid titanium, carbon fiber, steel threaded rod? Or did you use the stock pushrods?

The reason I ask is because the more I look at this jet, the more I see that it would not take much deviation from the servo to the elevator, to have a pitch down. Like I posted before there could be many culprits in this chain, which is why we're seemingly chasing a few cats.
Oct 29, 2020, 06:29 PM
Battery Puffer
Quote:
Originally Posted by janmb
The issue there is the rate at which the main pack voltage drops, not the level it drops to as such. Even under really, really serious load, a really bad 6S pack will still deliver 17-18 volts or so, miiiiles more than the BEC really needs. That is not the case he is making at all. The case is that the rate at which the pack drops from say 24V down to say 20 (because you hammer the throttle) makes the BEC having to adjust its switching very quickly to adapt, and that in a small time frame, that may lead to the output caps/filters not being properly filled. Even if that dip is very very short-lived, I guess it could in theory cause problems.
Good grief really. I don't think so. You seem to like to find ways to prove people wrong so you can be right. Your wrong my friend.
Oct 29, 2020, 06:48 PM
Registered User
janmb's Avatar
Quote:
Originally Posted by MarkF
Good grief really. I don't think so. You seem to like to find ways to prove people wrong so you can be right. Your wrong my friend.
I'm just explaining to you the content of what someone else claimed. Not my claims mate.
Oct 29, 2020, 06:51 PM
Flying R/C since 1964
kallend's Avatar
How hard is it to measure the voltage at the servos when they are stalled? Easier than all this speculation.

And I don't mean Hacker high current servos, I mean the ones supplied by MRC.
Latest blog entry: Make your own EDF afterburner
Oct 29, 2020, 07:02 PM
Foam addict
4stripes's Avatar
HobbyKing sells a nifty checker (mini wattmeter) for checking loads.
Oct 29, 2020, 07:20 PM
Mach One
captain MoMo's Avatar
Quote:
Originally Posted by nuts-n-volts
ProModeler. I denoted the two I think would be good to go with. They will work on 5v but with a little less max torque. Mind you I'm working on getting the controls all operating at 8.4v as well. Yeah, might be overkill, but it's an experiment in the making. The thing with ProModeler servos is that there is practically no slop in the gear train. Solid, professional all the way thru.

Let me ask you, MoMo. Did you upgrade the elevator linkages to solid titanium, carbon fiber, steel threaded rod? Or did you use the stock pushrods?

The reason I ask is because the more I look at this jet, the more I see that it would not take much deviation from the servo to the elevator, to have a pitch down. Like I posted before there could be many culprits in this chain, which is why we're seemingly chasing a few cats.
No I didnít upgrade the elevator linkage to solid titanium. I just used the stock setup.
Oct 29, 2020, 09:26 PM
low, left, & fast
nuts-n-volts's Avatar
Quote:
Originally Posted by captain MoMo
No I didnít upgrade the elevator linkage to solid titanium. I just used the stock setup.
The stock set up would be the very first thing I would replace on this jet. It must be stiff, stiff. Either 4-40 all thread, Titanium pushrods, or a carbon tube with all thread HySol'ed (epoxied) into each end and then ball links to each horn. There can be no slop in that linkage. The "up command" is in compression on these linkages. You're foolin' yourself if you think it's OK. It is probably the biggest part of failures that we have seen. That, and a nose heavy condition. I do mean well here.
Oct 29, 2020, 09:33 PM
Registered User
kenelder's Avatar
Has anyone had a problem making high speed inverted passes? The elevator pushrods are under tension when you push down to climb after an inverted pass.....
Oct 29, 2020, 09:48 PM
Registered User
Havenít read through this thread , but have to say I didnít like the looks of the elevator set up . Made a couple mods shortened the upgraded elevator servo extensions and moved the servos over with stronger rods
Oct 29, 2020, 10:00 PM
Registered User
Quote:
Originally Posted by Riverfront
Havenít read through this thread , but have to say I didnít like the looks of the elevator set up . Made a couple mods shortened the upgraded elevator servo extensions and moved the servos over with stronger rods
Good idea. The geometery looks much better.


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