I JUST HAD MY FIRST JET FLIGHT,WHAT A BLAST,EVERYTHING WAS GREAT TILL MY GEAR DID NOT COME DOWN.I HAD TO DO A BELLY LANDING IN THE DIRT.JUST SOME MINOR WING SCRAPES.I GOT LUCKY.ANYWAY I PUT THE JET BACK ON THE STAND AFTER PICKING IT UP AND HIT THE RETRACT SWITCH AND THEY WORKED FINE.MY QUESTION IS?IS THERE MORE THAN ONE TYPE OF AIR SWITCH?IS THERE A SPECIAL SERVO HORN?THIS IS SPRING AIR GEAR IT ONLY HAS A ONE WAY AIR CONNECT TO THE GEAR.THE SERVO HAS TO PUSH IN HARD TO ACTIVATE THE GEAR TO GO DOWN.HOW SHOULD THE SERVO BE HOOKED UP TO ACTIVATE THE SWITCH??ALSO AS SOON AS YOU TURN OFF THE RADIO THE GEAR RETRACTS,AS THE SERVO MOVES ONCE THE POWER IS SHUT OFF. ANY IMPUT WOULD BE GREAT!!!! THANKS TODD

Hi Todd,

This does not sound right at all. I have used Spring Air retracts for over a decade and have never heard of this.

The valve usually supplied by Spring Air looks like an electrical toggle switch and has little resistance to being moved from one side to the other.

The valve I usually use is made by Ultra Precision specifically for Spring Air retracts. It looks like a metal block with three nipples and a sliding cylinder that is moved by the servo. There is no resistance to the movement of the cylinder by the servo.

It sounds like you are using the Ultra Precision proportional brake valve to actuate your retracts. That valve does have a spring pushing back against the servo. If connected a certain way, it would indeed retract the gear when you turn off the power and the servo is pushed back.

Hope that helps,
...jim

PS. Please don't type in ALL CAPS. It makes it look like you are yelling. Just a suggestion.

This is how the spring-air valve should look like:



If you have the version they supplied a while back (the type you install below your servo and use the round servo horn) you can contact spring air at (321) 728-9002 and they would send you the newer valve.

Here is another version they had for a while. It mounted directly to a servo, there was a gimmick mounted on the servo horn to depress the button.

Vin...

THANKS A BUNCH GUYS.MY SWITCH IS NOT THE CORRECT TYPE, I SEE FROM THE PICTURES.IT IS NOT A TOGGLE BUT A PUSH IN PIN TYPE.WHEN PUSHED IN AND HELD THE GEAR IS DOWN,WHEN LET GO THE GEAR GOES UP. THANKS AGAIN TODD

I've used both kinds of air valves pictured in the previous posts and I personally prefer the "toggle" type..

The "button" type should be actuated by a cam rather than a servo arm.

BTW: I beleive both are Klippard products.
Johnny

Vin

That is the one I was referring to in my post. Thanks for posting the pic.

FWIW, I never liked that version. It puts a lot of strain on the servo arm.

Another thing that does not sound right:

Spring Air gear use air to retract and Spring to extend the gear??? They should require NO air to extend the gear to the down position??

Todd

FYI

Spring_Air made some retracts that uses air-up/air-spring assisted down. I had a set few years ago in my Y/A F-18 single.

It uses air down if you connect it, if not it uses spring action (do not ask me why).

This is the type of valve I used to close the gear doors on my Mig-29. When the gear leg was retracted ithit the valve sendig air to the door cylinder and closed the doors.

Hi, everyone,

After reading plaincrazy's article, I found he is right.
I guess he is using a toggle type air valve silimilar to the one that ghost_rider posted at #3 post.

But ghost_rider's is a traditional version that looks fine and works fine too.
As a dealer of Spring Air in Korea, I've tested and used several types of V/V from spring air for years.

The toggle type valve plaincrazy used had been produced for a short while, and discontinued.
He is correct on what he mentioned. It needs a quite deal of force to initiate legs down at the very beginning.
We've found the same problem and reported to Spring Air some years ago.

Plaincrazy, I believe you can ask a recall to Spring Air and you will be supplied by a new one. They now manufactures sliding type air valves like other conventional ones out there.

It was their only mistake they've ever made for a very short period of time, and a few has been made and supplied.

Hope above would be helpful to you.


T.Young Lee / Jet Aero Modelling, Inc.
www.jetaero.co.kr