In flight re-pressurizer
01-16-2012 | 03:50 PM
#1
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In flight re-pressurizer
I've seen the fail safes that will put the gear down if pressure is lost. Has anyone seen a device that can repressurize the gears and brakes if pressure goes too low in flight?
I could envision it using a regulated co2 cartridge to get the gears down and activate the brakes. Basically if the gear and/or brakes lose pressure, when the device gets the RC signal from the channel it then knows it ineeds to supplement pressure and kicks in a c02 cartridge to get the gear down and then does the brakes the same way on command. It then could then "reseal" the c02 liek a bb guns does, knowing pressure is lost over time but it would be nice peace of mind.
Thanks!
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01-16-2012 | 05:17 PM
#2
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From: farnborough, , UNITED KINGDOM
RE: In flight re-pressurizer
Go electric... nice idea though, just adds more complexity and a little extra weight to an already complex system with many potential points of failure.
Lado, Electron, plus others are forging new areas with electric gear.
marcs
Lado, Electron, plus others are forging new areas with electric gear.
marcs
01-16-2012 | 05:36 PM
#5
RE: In flight re-pressurizer
The Olympus HP has a pressure output port that could be used to maintain air pressure. I haven't heard of anyone who has used it for that purpose nor do I know how much pressure it puts out.
Phil
Phil
01-16-2012 | 05:55 PM
#6
RE: In flight re-pressurizer
ORIGINAL: marc s
Go electric... nice idea though, just adds more complexity and a little extra weight to an already complex system with many potential points of failure.
Lado, Electron, plus others are forging new areas with electric gear.
marcs
Go electric... nice idea though, just adds more complexity and a little extra weight to an already complex system with many potential points of failure.
Lado, Electron, plus others are forging new areas with electric gear.
marcs
01-16-2012 | 06:11 PM
#8
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From: Chicago, IL
RE: In flight re-pressurizer
Down and Locked just "electrified" a set of retracts for me for a 55 pound jet - they have motors for the largest available retracts.
Rob<br type="_moz" />
Rob<br type="_moz" />
01-16-2012 | 06:19 PM
#9
RE: In flight re-pressurizer
http://dreamworksrc.com/catalog/elec...er-p-1977.html
Dreamworks electric retract up tp 44 lb, The co2 cartridge sounds good. Also taking air pressure from any turbine and (T) it to the air tank would be interesting
.
Just my opinion
Dreamworks electric retract up tp 44 lb, The co2 cartridge sounds good. Also taking air pressure from any turbine and (T) it to the air tank would be interesting
.Just my opinion
01-16-2012 | 06:24 PM
#10
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From: Port Rowan,
ON, CANADA
RE: In flight re-pressurizer
I think most rc turbines have a pressure ratio of 2:1 to 3:1. At full throttle only going to get about 15psi to 30psi. Dont think its enough to actuate gear or brakes. If you add a check valve to stop air from going through the pressure port the wrong way will have even less pressure.
Geoff
Geoff
01-16-2012 | 07:05 PM
#11
RE: In flight re-pressurizer
ORIGINAL: pfact
The Olympus HP has a pressure output port that could be used to maintain air pressure. I haven't heard of anyone who has used it for that purpose nor do I know how much pressure it puts out.
Phil
The Olympus HP has a pressure output port that could be used to maintain air pressure. I haven't heard of anyone who has used it for that purpose nor do I know how much pressure it puts out.
Phil
I thought of this idea several years ago, but these engines being single stage do not have enough pressure for bleed air like the big boys... I considered a separate air tank with a servo or electronic valve to quick dump air into the retract system to blow the gear down and lock, but a lot hinges on the size if the leak you have if it will overcome the leak and have enough pressure to blow the gear down. It would be a one shot deal after you have determined you have no air it the retract system... Kinda a "Hail Mary" deal for sure.... Just what we need in the hobby... More drama !!!!
I have been there myself... Hit the retract switch and all the sudden the " Disaster like Music " starts playing in my head [X(]... Just like in the movies !!!!! Danno
01-16-2012 | 07:28 PM
#12
RE: In flight re-pressurizer
bypass air off the turbine is HOT and low pressure, if used as a backup (you have a leak) then the leak will be enough to allow the bypass air to flow at a high enough rate to melt the fittings on the turbine, not a good idea.
01-16-2012 | 07:35 PM
#13
RE: In flight re-pressurizer
A standby/emergency air system is a good idea, one I've thought of doing, never got round to it, but may add it to my SkyGate Hawk. Several real jets I've flown use exactly this system to get the gear down if the hydraulics dump.
For a model its light , simple and easy:
As the leak has occurred in flight the gear is up so the leak is almost certainly in the "UP" lines so the leak there is irrelevant when the "down" side of the valve is opened. So you need an extra air tank (you don't need a CO 2 cylinder but could be used) and the supply line is T'ed into the normal supply line to the gear valve via a Clippard air micro switch. You arrange the servo which actuates the gear valve to overtravel from the "down" position and contact the Clippard valve which opens and supplies standby air to the gear valve. You make the gear servo overtravel by mixing gear to gear and activating the mix via a snap roll button or similar so you dont need a separate servo or radio channel. So, select gear down, nothing happens, then activate the snap button and hold, emergency pressure is fed to the valve and down comes the gear. You don't absolutely need a another air tank, you could arrange the brake tank to be your standby supply.
Of course nothing is guaranteed as the crew of the Polish 767 recently discovered when they landed at Warsaw wheels up after it failed to lower on the standby system ! (If only they had checked ALL the DC circuit breakers !)
Tea finished back to cutting the grass !
Have fun,
David.
For a model its light , simple and easy:
As the leak has occurred in flight the gear is up so the leak is almost certainly in the "UP" lines so the leak there is irrelevant when the "down" side of the valve is opened. So you need an extra air tank (you don't need a CO 2 cylinder but could be used) and the supply line is T'ed into the normal supply line to the gear valve via a Clippard air micro switch. You arrange the servo which actuates the gear valve to overtravel from the "down" position and contact the Clippard valve which opens and supplies standby air to the gear valve. You make the gear servo overtravel by mixing gear to gear and activating the mix via a snap roll button or similar so you dont need a separate servo or radio channel. So, select gear down, nothing happens, then activate the snap button and hold, emergency pressure is fed to the valve and down comes the gear. You don't absolutely need a another air tank, you could arrange the brake tank to be your standby supply.
Of course nothing is guaranteed as the crew of the Polish 767 recently discovered when they landed at Warsaw wheels up after it failed to lower on the standby system ! (If only they had checked ALL the DC circuit breakers !)
Tea finished back to cutting the grass !
Have fun,
David.
01-16-2012 | 08:38 PM
#15
My Feedback: (2)
RE: In flight re-pressurizer
ORIGINAL: David Gladwin
A standby/emergency air system is a good idea, one I've thought of doing, never got round to it, but may add it to my SkyGate Hawk. Several real jets I've flown use exactly this system to get the gear down if the hydraulics dump.
For a model its light , simple and easy:
As the leak has occurred in flight the gear is up so the leak is almost certainly in the ''UP'' lines so the leak there is irrelevant when the ''down'' side of the valve is opened. So you need an extra air tank (you don't need a CO 2 cylinder but could be used) and the supply line is T'ed into the normal supply line to the gear valve via a Clippard air micro switch. You arrange the servo which actuates the gear valve to overtravel from the ''down'' position and contact the Clippard valve which opens and supplies standby air to the gear valve. You make the gear servo overtravel by mixing gear to gear and activating the mix via a snap roll button or similar so you dont need a separate servo or radio channel. So, select gear down, nothing happens, then activate the snap button and hold, emergency pressure is fed to the valve and down comes the gear. You don't absolutely need a another air tank, you could arrange the brake tank to be your standby supply.
Of course nothing is guaranteed as the crew of the Polish 767 recently discovered when they landed at Warsaw wheels up after it failed to lower on the standby system ! (If only they had checked ALL the DC circuit breakers !)
Tea finished back to cutting the grass !
Have fun,
David.
A standby/emergency air system is a good idea, one I've thought of doing, never got round to it, but may add it to my SkyGate Hawk. Several real jets I've flown use exactly this system to get the gear down if the hydraulics dump.
For a model its light , simple and easy:
As the leak has occurred in flight the gear is up so the leak is almost certainly in the ''UP'' lines so the leak there is irrelevant when the ''down'' side of the valve is opened. So you need an extra air tank (you don't need a CO 2 cylinder but could be used) and the supply line is T'ed into the normal supply line to the gear valve via a Clippard air micro switch. You arrange the servo which actuates the gear valve to overtravel from the ''down'' position and contact the Clippard valve which opens and supplies standby air to the gear valve. You make the gear servo overtravel by mixing gear to gear and activating the mix via a snap roll button or similar so you dont need a separate servo or radio channel. So, select gear down, nothing happens, then activate the snap button and hold, emergency pressure is fed to the valve and down comes the gear. You don't absolutely need a another air tank, you could arrange the brake tank to be your standby supply.
Of course nothing is guaranteed as the crew of the Polish 767 recently discovered when they landed at Warsaw wheels up after it failed to lower on the standby system ! (If only they had checked ALL the DC circuit breakers !)
Tea finished back to cutting the grass !
Have fun,
David.
Of course, I just use Tamjet gear savers on all my jets and not experienced a "Low Air" gear fail scenario yet. Tamjet gear saver is much smarter than me!
Shaz
01-16-2012 | 09:36 PM
#17
My Feedback: (1)
RE: In flight re-pressurizer
Check this out , redimade solution, Co2 sized canisters used with NOS and an RC solenoid based boost, they inject NOS into carbs.
http://www.nitrousexpress.com/produc...ls.php?id=1436
http://www.nitrousexpress.com/produc...ls.php?id=1436
01-16-2012 | 09:38 PM
#18
Thread Starter
My Feedback: (11)
RE: In flight re-pressurizer
Thanks for the link!
I may just end up making my own using an arduino and BB gun parts. I'll make a build thread if I do it.
The main problem is the cost of pressure tranducers starting at about $30 it gets expensive quick!
I may just end up making my own using an arduino and BB gun parts. I'll make a build thread if I do it.
The main problem is the cost of pressure tranducers starting at about $30 it gets expensive quick!
01-17-2012 | 12:22 AM
#19
Banned
RE: In flight re-pressurizer
If you use the latest Jetronic duel acting valve you can simply set it to cut off all air to the system after about 5 seconds and maintain it in the tank. This will only not work if the leak is at the valve, the tank or the fill check valve. The most likely of these is the fill check valve and it is quite simple and cheap to use 2 of these in series if you wish or simply put a festo stop end over the fill pipe after you have filled the system.
Deno
Deno
01-17-2012 | 03:41 AM
#20
RE: In flight re-pressurizer
I've used a system for many years that automatically drops the gear in the event of pressure loss.
It doesn't use bleed air, CO2 cartridges, electronic valves, solenoids, extra air tanks or electric motors.
Instead, they use ....... a spring.
http://www.retracts.com/index.htm
John.
It doesn't use bleed air, CO2 cartridges, electronic valves, solenoids, extra air tanks or electric motors.
Instead, they use ....... a spring.
http://www.retracts.com/index.htm
John.
01-17-2012 | 05:20 AM
#22
RE: In flight re-pressurizer
ORIGINAL: Boomerang1
I've used a system for many years that automatically drops the gear in the event of pressure loss.
It doesn't use bleed air, CO2 cartridges, electronic valves, solenoids, extra air tanks or electric motors.
Instead, they use ....... a spring.
http://www.retracts.com/index.htm
John.
I've used a system for many years that automatically drops the gear in the event of pressure loss.
It doesn't use bleed air, CO2 cartridges, electronic valves, solenoids, extra air tanks or electric motors.
Instead, they use ....... a spring.
http://www.retracts.com/index.htm
John.
TOUCHE !!!!!! Sometimes the obvious is so obvious it is never thought of !!!
I use them myself, never came to mind in this discussion... It's like trying to over engineer a peanut butter and jelly sandwich.Danno
01-17-2012 | 05:54 AM
#24
RE: In flight re-pressurizer
Electric retracts (screw jacks) all the way!
Electron and lado cater for the big stuff, and even have an EMF braking system (no air required)!
There is however, an on board compressor being developed by JetTronics!
This would cater better for pneumatics than Co2 being pumped directly into the system!
It would cause long term damage to the seals in the valve gear and retracts! It has never been an option in industry, due to icing (the seals crumble and split)![&o]
JT
Electron and lado cater for the big stuff, and even have an EMF braking system (no air required)!
There is however, an on board compressor being developed by JetTronics!
This would cater better for pneumatics than Co2 being pumped directly into the system!
It would cause long term damage to the seals in the valve gear and retracts! It has never been an option in industry, due to icing (the seals crumble and split)![&o]
JT
01-17-2012 | 06:19 AM
#25
RE: In flight re-pressurizer
ORIGINAL: John Tancock
Electric retracts (screw jacks) all the way!
Electron and lado cater for the big stuff, and even have an EMF braking system (no air required)!
There is however, an on board compressor being developed by JetTronics!
This would cater better for pneumatics than Co2 being pumped directly into the system!
It would cause long term damage to the seals in the valve gear and retracts! It has never been an option in industry, due to icing (the seals crumble and split)![&o]
JT
Electric retracts (screw jacks) all the way!
Electron and lado cater for the big stuff, and even have an EMF braking system (no air required)!
There is however, an on board compressor being developed by JetTronics!
This would cater better for pneumatics than Co2 being pumped directly into the system!
It would cause long term damage to the seals in the valve gear and retracts! It has never been an option in industry, due to icing (the seals crumble and split)![&o]
JT
If your going compressed anything, use Nitrogen.... We use that on everyday ops for retracts and brakes now.... Zero moisture....
Danno
