My winter project is to make retracts for my top-flite P47. The basic Robarts design looks like good start and my question : What are the pros and cons of air down versus spring down . Thanks. Syd A

Hey Syd,
You may want to move this to the warbird forum for a better response.

Til then I will add my inflation adjusted two cents.

I prefer spring down units when use air retracts for the fact that should you develop a leak or expend your air supply, the gear will come down and lock.
Units that use air both ways require a larger volume air reservoir and give you no certainty of a down and locked condition when the air charge gets low.

But in the end Lados are my favorite!

TG,  thanks for the input on the LADOS.  I am also slowly getting into the world of retracts and have shyed away from them because of the problems folks have had with them.

The only problem with Lado is that they are a new startup company going thru growing pains.
The product is fantastic and the family running is doing all they can to make their customers happy.
As for durability?
The midair I was involved in this last weekend at the races was a headon with a rate of closure of approx 280 MPH.
Part of the other plane destroyed my left wing leading edge and sheeting in front of the mounting blocks for my retracts and above them.
When I hauled the wreckage back to the pits to check things out, the Lados worked as if nothing had happened.
I will be slowly switching all my pneumatic retracts out for Lados.

That's what I like to hear.  The Lados remind me of the old Kraft retracts in the 70's being individually powered.