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Pushrods or Thread and spring? What to do... Darn Swedes!

Hello! Long time viewer, first time poster.

So after watching David and Josh playing around with the DHL and having an old Mosquito HLG in my garage. I decided that I should buy a DHL. After a little research, I bought a Blaster 3 (Thanks David ;) ). No problems with the build so far and have installed the pushrods but after some thought and a little digging it appears that some like the pushrods while others swear on the spring and string for control surfaces. Are there any drawbacks other than weight?

Thanks in advance.



Active member
Are you assuming the string and spring is heavier? Done appropriately it is stronger and lighter. Which why it is popular to use them on light aircraft!
Not at all. I was more or less wondering the pro's and con's of each. I went with the pushrods for now with the notion I can always swap them out at a later date.
Thanks for the reply.
This is the first time I've heard of the spring and string method for control surfaces. Sounds interesting if I'm picturing it correctly. A spring forces the surface in one direction and a servo is used to pull in the other via the string, is that right? If so, and I could be wrong, wouldn't that fatigue the servo more than a push rod? The servo would not only be fighting the wind resistance against the surface but also the spring resistance. Just a thought. Like I said first time I've ever heard of it.


Dedicated foam bender
I was picturing a pull-pull string setup with springs acting like a servo saver...but your described method actually makes more sense. A light spring shouldn't put too much strain on a servo, at least not any more than airflow over the surface would as long as it's light enough.