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hydraulic retracts

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Old 02-01-2013, 04:44 PM
  #1
mustang493
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Default hydraulic retracts

has anyone any experience in converting air retracts to hydraulic. i'm thinking of using jet fuelpump as the hydraulic motor and controlling with Arduino micro controller. Anyone interested in the idea. One thing that irritates me with air retracts is the lack of control. it's either bang up or bang down.
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Old 02-01-2013, 05:06 PM
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Edgar Perez
 
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Default RE: hydraulic retracts

There are a lot of details in the jet legend mig-29 thread about converting air to hydraulic. Go take a look using the search function
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Old 02-01-2013, 05:07 PM
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Default RE: hydraulic retracts

Save your time and frustration.........just go electric
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Old 02-01-2013, 05:14 PM
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mustang493
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Default RE: hydraulic retracts

Already played with electrics. Just think running fluid at 100psi would give a much smother travel and would be fairly easy to convert. Have surfed for some info but i run on a budget so can't go for these expensive systems.
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Old 02-01-2013, 05:33 PM
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Default RE: hydraulic retracts

Been using hydraulics for years. The latest conversion is to my Skymaster A10. I can't see myself going any other way now. Same speed up and down no leaks just brilliant.

m
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Old 02-01-2013, 05:37 PM
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Default RE: hydraulic retracts

Mick will you share your designs.
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Old 02-01-2013, 05:43 PM
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Default RE: hydraulic retracts

Of course I'm not a million miles from you, live in Southend
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Old 02-01-2013, 05:46 PM
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Default RE: hydraulic retracts

i played with the hobby king hydraulic system and it works good ,i think it is priced right for what you get
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Old 02-01-2013, 06:24 PM
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Default RE: hydraulic retracts

http://www.hobbyking.com/hobbyking/s...Retracts_.html
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Old 02-02-2013, 09:45 AM
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Default RE: hydraulic retracts

The Hobby King hydraulic retracts are made by UMS, of India. I have used this system on my Mig 29 and have now got them installed on my FB15E twin. It works well, is not very heavy. Many people see electric retracts as the way to go but my flying buddy has had nothing but trouble with his Lado retracts. He has had as many wheel up landings as good ones due to jamming and stalling of the electric motor. Give hydraulics a go.




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Old 02-02-2013, 09:51 AM
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Greg Wright
 
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Default RE: hydraulic retracts

The system say's for two gear only. What are you doing to operate three gears. Is it just a matter of T-ing the nose leg into the system.
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Old 02-02-2013, 11:07 AM
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Default RE: hydraulic retracts

mustang 493

Take a look here      http://umstech.in/view_product_detai...anding%20Gears

Regards
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Old 02-02-2013, 12:42 PM
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Default RE: hydraulic retracts

Yep, just use a T union and add a 3rd. The Hydraulic oil is obviously denser than air so it won't leak even if you use robart rams etc! I just use Dot4 brake fluid and haven't had any trouble yet!
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Old 02-02-2013, 03:27 PM
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Default RE: hydraulic retracts

Thinking of converting AeroWorks P51 to hydraulic would this be a good idea using their gear?
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Old 02-02-2013, 03:55 PM
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Default RE: hydraulic retracts

Yes I'm going to build a hydraulic system. Having looked at the umstech gear I think an improvement wouldbe a pressure sensor to tell the control when the gear is up or down. I've found a cheap source of micro pumps in china so hope to be able to build a tri gear system for under £60.00. I know that makes no sense when you can buy it for £70.00 but it's the challenge. I think it would be interesting to incorporate brakes and air brakes into the design. Thanks Dragan, john and Mick for your replies.
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Old 02-02-2013, 05:43 PM
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Default RE: hydraulic retracts

Hi Guys,

Given the price on the HK unit, I'm going to order one and give it a go. Has anyone tried using this setup in conjunction with JetTronic valves and, if so, did it work out okay?

Thanks,
Garrett
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Old 02-02-2013, 08:41 PM
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Default RE: hydraulic retracts

I've used jet tronic valves to control the gear doors. I've also used program mixes in my tx. For the hydraulic control I am using the UMS controller, which senses electrical load. I have also used micro switches in the past. I know Mick uses hydraulic control on his doors as well. No more coming open under high g loads.


John


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Old 02-02-2013, 11:32 PM
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Default RE: hydraulic retracts

Just ordered HK hydraulic system,  no point reinventing the wheel.  Mick if you're reading this do you build your own rams for gear doors etc?
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Old 02-03-2013, 01:14 AM
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Default RE: hydraulic retracts

No I have used the originals. I think you may find 3mm lines for the gear too small, mine are all 4mm.

m
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Old 02-03-2013, 01:30 AM
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Default RE: hydraulic retracts

How do you address the problem of removing the wing and disconnecting the gear lines??
Thanks,
Vin...
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Old 02-03-2013, 01:34 AM
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Default RE: hydraulic retracts

Garrett,

I've got a UMS hyd unit here if you want it.

Let me know.
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Old 02-03-2013, 01:45 AM
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Default RE: hydraulic retracts

Wing removal is not a problem, you can fit self seal festos (QSK4). Or make sure the pressure is zero and just disconnect, you get almost no fluid loss. Furthermore the system does not need bleeding.

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Old 02-03-2013, 01:50 AM
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Default RE: hydraulic retracts

Here is a video of my A10, about half way through you can see the gear operation and how the transit speeds are similar.

http://youtu.be/-KNPjkWOVPU

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Old 02-03-2013, 01:59 AM
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Default RE: hydraulic retracts


Quote:
ORIGINAL: mick15

Wing removal is not a problem, you can fit self seal festos (QSK4). Or make sure the pressure is zero and just disconnect, you get almost no fluid loss. Furthermore the system does not need bleeding.

m
Why does the system not need bleeding, where does the air go??
Vin...
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Old 02-03-2013, 02:08 AM
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Default RE: hydraulic retracts

Some air in the system has no effect, if the volume of the cylinder is greater than the volume of the pipe it will bleed itself.

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