KingCat Flaps and Matchbox.
 

Do you really need a Reverse servo for the Flaps since you run both servos through the MatchBox.

Can't the MatchBox do the Reversing of the one servo for you??

Changing to JR8411 digitals from the JR2721's.

THANKS, TOM

RE: KingCat Flaps and Matchbox.
 

Don't need a reversed servo, Matchbox will take care of it if needed.

RE: KingCat Flaps and Matchbox.
 

You can either run a reverse servo OR a matchbox.....or if you have enough channels, like on the 12X, you can run flaps on separate channels, and reverse it in the TX, and forget about the matchbox and reversed servo.

In my 4 y/o KC/Wren 160, with a 12X and 1221, I run no matchboxes or reverse servo. I also run 8411's all around. Haven't touced them since I installed them...... 500+ flights.

Take care setting up the flaps with 8411's. They will draw mucho juice if you stall them. Use an inline ammeter for safety.

RE: KingCat Flaps and Matchbox.
 

Tom, aren't the servos orenited in thier pockets where no reversing is needed. It's been a while. I agree with you on the ammeter.

RE: KingCat Flaps and Matchbox.
 

Was just going by the BVM servo list and it said JR8411 Forward and Reverse. Don't remember if mechanically they are set the same way.
Using a JR10X plus Spektrum AR9000 for guidance. Also buying the HANGER-9 Current/Voltage meter to check for stalls.
Has JR8611's all around except for FLAPS. The way it was when I bought it.

THANKS, TOM

RE: KingCat Flaps and Matchbox.
 

I stand corrected, looked at the list. Anyway I was right about matchbox;)

RE: KingCat Flaps and Matchbox.
 

You have 9ch to work with in that setup. I assume the elev`s are using one ch so you can spilt the rudd / steer in aux 4 and split the flap ch with aux 2 so you wont need a matchbox or reverse servo.
V..

RE: KingCat Flaps and Matchbox.
 

if necessary a matchbox is a much better choice then reversed servos, reason being the reversed servos don't match the degree of travel that the non reversed do, the techs at Horizon told me the reason was the tolerance between the resistors they use when reversing. they tried their best to get me a matched pair on several occasions but i always ended up using a matchbox or mixing 2 channels of the receiver.

RE: KingCat Flaps and Matchbox.
 

Be aware that using a matchbox for both flap servos limits the total current draw to 3A. The single servo plug into the RX is the limit factor. Done all the time but be aware. I flew a KingCat on a DX7 using a tri harness for the rudders/steering. The flaps on a matchbox. All was well BUT it bothered me to think that the flap servos could draw much more than 3 amps combined when they are deployed. Comments?

Dave

RE: KingCat Flaps and Matchbox.
 

Hello,

How does a matchbox limit the current? Or are you are talking about the connectors on the RX?

Regards,

RE: KingCat Flaps and Matchbox.
 

"The single servo plug into the RX is the limit factor."

Dave

RE: KingCat Flaps and Matchbox.
 

If you are really concerned about the current just use a seperate battery for the matchbox-it has that capability. Scotty

RE: KingCat Flaps and Matchbox.
 

I've read many times that a servo connector is limited to 3 amps but truth be known (and you can put it on the scope and test it yourself) with 20 awg wire the pins at the connector will carry over 7 amps before you get excessive heat build up and a voltage drop across the pins. at over 10 amps it quickly starts to melt the wire insulation but the connector pins still carry the load.

RE: KingCat Flaps and Matchbox.
 

Yes KC, I agree. The issue at high current is the self heating of the pin, then the resistance increase with the attendant voltage drop . They have to be safe on those specs, I don't fault them. But for short uses over 3 amps I don't think there is any problem

RE: KingCat Flaps and Matchbox.
 

I use the power box on my KC. does the lot and allows you to align the levators,rudders,nose wheel flaps and ailerons really easily. Tom.

RE: KingCat Flaps and Matchbox.
 

Andy Low now specs his JR plugs and switches at 4A continuous.....I charge my A123's with a Cellpro charger at 4A continuous with a JR plug and the plug and wire are barely warm to the touch after 5 minutes.....

RE: KingCat Flaps and Matchbox.
 

Thanks for all the info everyone. Going to use 2 Forward JR8611's on the Flaps.
Ordered 2 new JR8611 for the Ailerons and going to use the old Aileron ones on the Flaps.

THANKS, TOM