Ram Air Turbines
Thread Starter
Join Date: Jun 2009
Location: Singapore
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
Ram Air Turbines
Anybody know what is required to test one of these? Is there a test stand out there we can be used to test these components or do we need a wind tunnel together with a specialize test stand?
I think most big jets have a test function backdrive mechanism that reverses the hydraulic/electric motor to drive the RAT. 
Join Date: Jul 2001
Location: France
Posts: 48
Likes: 0
Received 0 Likes
on
0 Posts
Rats
In a previous operation I was involved in that operated 2 CL604 aircraft, we would deploy the RAT prior to landing before a maintenance check.
Special work sheet to confirm everything OK signed by commander.
RAT (CL604) is subject to NDT on blades after deployment. With is done the Rat was stowed ready for use.
No great shakes really.
MB
Special work sheet to confirm everything OK signed by commander.
RAT (CL604) is subject to NDT on blades after deployment. With is done the Rat was stowed ready for use.
No great shakes really.
MB
Join Date: Oct 2006
Location: berkshire
Posts: 0
Likes: 0
Received 0 Likes
on
0 Posts
testing RAT
To test the RAT on a VC10, just an electric generator, so no hydraulic backdrive, a diesel engine driving a fan on a trolley was supplied which was put in front of the lowered RAT blades, and with lots of noise it just about got the RAT up to frequency and supplied power.
On later aircraft and with H.and S. the back driven RATs had to have a shield/cover over the spinning blades, which was not very well made locally, Boeing one being to expensive to buy, the blades hit the the shield
and wrecked them. Another case of penny wise pound foolish.
On later aircraft and with H.and S. the back driven RATs had to have a shield/cover over the spinning blades, which was not very well made locally, Boeing one being to expensive to buy, the blades hit the the shield
and wrecked them. Another case of penny wise pound foolish.
Join Date: Aug 2007
Location: In the library
Age: 85
Posts: 117
Likes: 0
Received 0 Likes
on
0 Posts
Rat Test
As far as I remember on the 757 & 767 you could back drive the RAT from the hydrualics.
The M.M. gave you the figures to watch for.
On another point I have to say I went on several test, pre delivery flights where one of the tests was the RAT. I was very inpressed to observe the main Hydrualics turned off with zero pressure on the EICAS screen, the RAT deployed & flying the Lambourn hold on the autopilot with no problems of any sort.
tristar500
The M.M. gave you the figures to watch for.
On another point I have to say I went on several test, pre delivery flights where one of the tests was the RAT. I was very inpressed to observe the main Hydrualics turned off with zero pressure on the EICAS screen, the RAT deployed & flying the Lambourn hold on the autopilot with no problems of any sort.
tristar500
Join Date: Jun 2008
Location: Inverted
Posts: 106
Likes: 0
Received 0 Likes
on
0 Posts
On the A320's, there is a cage to go around the RAT and there is an external hydraulic power supply which drives the RAT. Then you can set up a control panel and control the speed.
Not much info im afraid. It was awile ago since I last did it.
c24
Not much info im afraid. It was awile ago since I last did it.
c24
Join Date: Aug 2007
Location: Cambridge
Posts: 59
Likes: 0
Received 0 Likes
on
0 Posts
RAT
Iv'e done this test in a hangar on an a320, what happens is the Rat is covered with a cage and then an external hydraulic rig is connected to the aircraft to drive the RAT, then the blue pump is selected on and the test is to see whether the RAT supplies the hydraulic pressure required (2500-3000psi).
Join Date: Mar 2009
Location: Peterborough
Age: 60
Posts: 6
Likes: 0
Received 0 Likes
on
0 Posts
There is a touch more than just putting the blue system on, there is also the check to see the correlation between flow/speed and pressure and remember at the end of the test make sure you do not empty the blue system reservoir, its very easy to do and a tad embarrassing when the a/c goes back to the line with blue system empty DOH!! 
Join Date: Jul 2009
Location: omaa
Age: 41
Posts: 9
Likes: 0
Received 0 Likes
on
0 Posts
RAT
RAT spin test on A320,A330,A340/300/500/600,we use external hydraulic motor that spins RAT hydarulic pump.but it requires external hydraulic power generator.believe me it's risky.once the rat blade sheared and damaged the wing structure.
In B777 we dont need external motor and power generator.it has rat check out module where we can reverse fluid direction so the rat hyd pump acts as motor.in this case we have to pressurize centre system with ADP to meet high flow demand.
In B777 we dont need external motor and power generator.it has rat check out module where we can reverse fluid direction so the rat hyd pump acts as motor.in this case we have to pressurize centre system with ADP to meet high flow demand.
