Vincent

My Feedback: (61)

Thanks Mick...on the HK system do you know how they make the travel stop??
Vin...

johnls

The HK(UMS), system uses an electric controller, that senses the current, to control the pump. The 5 way valve controls the direction of the fluid for gear up or down. When the gear is fully extended or retracted the pump works harder the current goes up, this is sensed by the controller which then shuts off. This point can be changed by adjusting a potentiometer pot. Go to the UMS web site and download the operating instructions. I disconnect my hydraulic lines, because with the length of the F15 I have to take the nose off. Depressurise the system, by moving the 5 way controller to a central position, and the lines will disconnect with virtually no fluid lose. By the way, the fluid should be as thin as possible. I use sewing machine oil. 4 mm pipes are the best if you can install them and you can get festo tubing that is rated for 200 psi. I have had festo air line split.


John

mick15

My system is controlled in a different way to John’s, I have an accumulator made from an old retract cylinder with a spring fitted to the airside, therefore the switching pressure is determined by the value of the spring. The piston rod operates a micro switch, which controls the pump through a relay. The relay is controlled through a radio program, which gives me a timed transit the relay can also be operated by a switch extra to the program, this gives me added security. This system has worked perfectly over time fitted to numerous models; early on I did have some issues with the factory ECUs, which is why I stopped using them.

Incidentally, the extra program switch is essential on my Sea Fury’s folding wings as this cannot be actuated from a timed program. As John rightly says care is needed with this system as pressures of over 200psi can be achieved!

m

AV8ATOR

My Feedback: (5)

Hello

Could you tell me where I can look at or who makes this product. (HK hydraulic system),

Thanks

dadragon

I got the 3 gear kit from UMS a few years ago and using the Sierra retracts on a 120"AD-SKYRAIDER.and MICK thank YOU for your info and help on setting up the system all has been trouble free since the change over,will never go back to air.Oh yah and the flaps are hydraulic too.

tow

How do you get a 4mm tubing to fit the barbs on the air-retracts?

Vincent

My Feedback: (61)

You can use a few of these...

http://dreamworksrc.com/catalog/fest...ctor-p-58.html

johnls

Better still replace the barbs with this.





John

tow

Who carry those.....Dreamworks?

johnls

Possibly. Here in the UK any Festo supplier can get them or Ali or Motors and Rotors as well. The part number is Festo QSM3-4 for straight fittings or QSML M3-4 for 90 degree fittings. Try google to find a supplier in Norway.


John

tow

Thank You. Will give it a try

Vincent

My Feedback: (61)

The festo will work only if the gear have threaded nipples on them. Many are just pressed in so you may have to leave the original 3mm end intact and just convert the 4mm tubing with a fitting right near the retrac.
Vin...

mick15

You can drill and tap you know to do a proper job.

m

tow

Not sure if the barbs are press or threaded. Will find out when I get them in house. It`s the Intairco retracts for the CARF MiG-15....

FenderBean

I am a big advocate for electric and i use down and locked with great success. I have had my gear amp out a few times due to some binding that was easily fixed. The good thing about the electric and what makes me feel good is even if they bind and amp out you just flip the switch and they come back down. The weight is less than the air system would be.
I originally thought about doing hydraulic but the possibility of a leak is the same as the air system. Correct me if i am wrong but the hydraulic system still requires the system to be pressurized to function? If you get any kind of leak, and cylinders do occasionally whats to prevent the gear from not coming down? I would think for these reason alone electric would be safer?

tow

Being among those who got sick and tired of the dreaded leaks of pneumatic systems I also thought of converting to electric. I find that operation to be rather costly, therefore the hydraulic conversion seems worth trying. I`m not claiming you won`t get leaks in this system too, and maybe with similar devastating result, but in my opinion it should be much easier both to identify and fix. Secondly you can use existing rams and valves and also you get rid of the bang-bang action of pneumatics. Is my reasening wrong or have I missed something?

FenderBean

I agree with cost, which is why i originally planned on trying to hydraulics but after pricing stuff out its not.
The cost of the valves/pump/sequencer is about the same if not more. When its all said and done, plus fittings with airlines adds up also. Just thoughts im all about the best solutions and would have no issues going hydraulics if it was the better solution either way both are better than air in my opinion.

mustang493

Just had a long conversation with Mick and he's nailed the whole hydraulics thing.  With micks permission I'll make a system using his accumulator idea and post it here.

tow

OK now you can get a set from HK for about 100 $ it certainly is worth a try..........

mr_matt

My Feedback: (10)

Mick's idea (or whoever came up with it) for the spring adjustable pressure switch is brilliant and takes care of the current sensing or limit switches. The pump runs whenever it needs to.

causeitflies

Check out one of B-1 Bob's early videos where he was considering using the same system as mick. It gives a good look at how the system works and was made with parts laying around the shop.
The video was a made few years ago but is worth finding if anyone is interested in the system.

tow

Just got one of the conversion-kits from HK. No user-manual whatsoever. Help anyone???

mick15

What do you need to know?
You can pm me or talk in open forum up to you.

m

tow

Basically how to connect/setup the whole calamazoo.........I understand the controller-box plugged to the RX controls the pump running, this much is clear, what controls pressure / start/stop function..............How about any air in the system......What is the best oil to use, will mineral-oil (sewing-machine) affect O-rings in cylinders?
Lot of questions I know, but appreciate any help.

Justflying1

UMS make the product.

http://umstech.in/products.php