Spektrum DSP75

[nathanmroth]

I was just wondering if anyone is using the Spektrum DSP75 7.5 gramservo's? I am thinking about trading out the stock E-Flite's for them,

[skigolfmike]

Yes - I am using them on my 400 as CCPM servos, They work great. Just don't have a blade strike. (Same gears as E-Flite servos)

Things to be aware of if you switch to DSP75s. You will have to reverse the travel on the servos in the TX. (E-Flite servos seem to be backwards compared to everything else.) Also, the throw in degrees is less than the stock servos. You will lose pitch and roll authority if you don't make increase the travel adjustment. If you increase the travel adjustment to much, the servos will stop at their endpoints before you expect them too.

What I did was get the Spektrum servo programmer, program the servos in heli mode with the programmer, use the programmer set center with level servo arms, and increase the endpoints of the servos to their maximum. Then I used the Trueblood swash leveling too to level the swash at mid-stick and the end points. You level the swash mechanically at mid-stick and you use the travel volume to level the swash at the endpoints. Then I set the pitch to +/-10* and flew it. Works great.

[constantCrash]

I Just replaced all my servos in the B400 with DSP75s, I'm going to get the programmer to fix the throw and endpoint issue. What I'm wondering, is Do I need to buy an external BEC or is the E-flight one still adequate? I'm only to the point of being able to do some forward flight so I'm not hard on the servos yet. (I'm also 25 flights in with zero crashes).

[Wolfpackin]

I'd use the HS65HB's for cyclic and maybe the DSP75 on the tail.
You can find the Hitecs for the same price as the Spektum servo and I think the HS65's are more durable.
I had the DSP75 on the tail for a while but it failed (two wires came unsoldered) so I'm not thrilled with them or the E-flites any more.
The HS65's on cyclic were a huge improvement in performance.

[Mon_t]

I'd use the HS65HB's for cyclic and maybe the DSP75 on the tail.
You can find the Hitecs for the same price as the Spektum servo and I think the HS65's are more durable.
I had the DSP75 on the tail for a while but it failed (two wires came unsoldered) so I'm not thrilled with them or the E-flites any more.
The HS65's on cyclic were a huge improvement in performance.
Also if you somehow manage to strip a hs65-hb, you can easily stick a metal gear set. The MG's are next to indestructible. The spektrum servos would be an improvement none the less.

[constantCrash]

What about an External BEC, is it absolutly required if you go to DSP75's ? how about HS65's (I know it's probably a good thing to do, but for just light flying do you think i'll be okay till funds free up?)

[skigolfmike]

I ran all DSP75s for a while with the stock gyro and had no problems with the ESC BEC. It was when I put on the GY401 and the JR DS3400G that I needed the external BEC.

[constantCrash]

Thank you very much for the response skigolfmike. I really wish more ESC manufactures would start putting switching BEC's into the smaller ESC. I can't see it adding more than a couple of bucks to the price.

[skigolfmike]

I know CC is going to add ESCs to their product line that have internal switching BECs.

One thing to be aware of on the B400 is the ESC motor combo seems to be pretty well tuned to each other. When I put on a Phoenix 35 I lost about ~300 rpm of head speed no matter how I set it up. If you want to try gov mode with a phoenix ESC you will need another motor.

[Wolfpackin]

What about an External BEC, is it absolutly required if you go to DSP75's ? how about HS65's


The temps on my ESC went down after installing the HS65's.
No external BEC.

Makes sense as analog servos draw less amps.