p.j

Hi all. I will be building my first gas powered plane this winter , a BUSA 1/4 scale Sopwith Pup. Since I have only had 40 & 60 size planes before I am not sure what size servos I will need for the Pup. I would like to use JR equipment if I could as I have had excellent results with there servos in the past. So if you have any experience with WW1 1/4 scale planes I would appreciate any suggestions you my have.

Thanks P.J

khodges

My Feedback: (1)

Since these planes don't fly all that fast, there's not much force required to move the control surface against the slipstream. Standard servos will work on these planes fine. I don't know the JR models, but something like a Futaba 3001 is okay, a 9001 is better (coreless, a bit more torque, but more expensive). Also, the 9001's aren't recommended for NiMH batteries due to current draw requirements.

XJet

I wouldn't recommend the use of standard sevos on a 1/4scale plane.

They may fly slow but the surfaces are large and the effect of the propwash on the rudder and elevator can be enough to overload a 50oz/in servo.

It's also a good idea to consider using metal-geared servos on 1/4 scale machines. The vibrations from larger engines tend to put a lot of stress on nylon gears and that can cause problems.

Something like a Hitec HS645 would be fine and relatively cheap ($35) -- I'm sure Futaba has an equivalent metal geared 100oz-in (or better) servo for a reasonable price.

Keep your standard servos for those 40-60 sized ships.

Oh, and modern NiMH packs are more than up to the task of running heavy-duty servos. Futaba's warning is a bit out dated. Just make sure you stay away from those ultra-high capacity AAA and AA packs. Go for a 2/3A pack and you can get 1400mAH that will handle 20A of draw (about five times what you're likely to see) with ease. Another benefit of the 2/3A packs is that they take a fast-charge very nicely. 20 minutes from flat to full means you can fly all day if you take your field-charger.

dirtybird

My Feedback: (5)

I disagree.
I have a Weeks special powered with a G45 that I have been flying since 1997 with standard servos. Two of the servos are aileron servos on the bottom wing that work the ailerons on the top wing as well.
I don't recall if stronger servos were available when this was built but the standard servos work just fine.

avionette

example

for 1/4 sopwith pup aileron what hitec or futaba servos i 'll put?

DadsToysBG

My Feedback: (35)

You also have the JR ST 126mg at 126oz with 4.8 volts. They are in a standard size case. Dennis