The most common problem with air systems in jets?
04-22-2011, 06:23 PM
#1
Thread Starter
The most common problem with air systems in jets?
Im just curious what are or if there are any common failure points. I am thinking about converting my soon to be jet from air to electric gear system and just would like some thoughts. I have an EDF jet with electric retracts and I love them, the only problem would be converting my gear doors to electric but I would if the pros out weight the cons. I know the time for extending in a flame out or emergency can could be an issue. Just thoughts, no flames please this is a forum for discussion so lets keep it nice. Thanks up front
04-22-2011, 06:53 PM
#2
RE: The most common problem with air systems in jets?
ORIGINAL: FenderBean
Im just curious what are or if there are any common failure points.
Im just curious what are or if there are any common failure points.
User error: failure to fill your airtanks.
User error: failure to annually oil your cylinder's O-rings and grease your brake valve.
If your air gear struts bind during deployment or stowing in the undercarriage, no harm to the system will be done and you can sometimes 'shake' it free during flight.
If your electric gear binds during the same scenario, I can only guess that it will drain your battery at a high current draw.
04-22-2011, 07:03 PM
#3
RE: The most common problem with air systems in jets?
user error is usually the culprit....if properly setup, works every time....a good quality manufacturer is also a must.....you get what u pay for....air is very reliable properly done....
04-22-2011, 07:45 PM
#4
Thread Starter
RE: The most common problem with air systems in jets?
Cool how often should one oil/replace the O rings, I'm pretty anal so knowing me I would fill the air tank every time.
04-22-2011, 08:43 PM
#5
RE: The most common problem with air systems in jets?
Another thing not touched on yet is when your building/rigging/maintaining your air system NEVER us a x-acto knife to cut the air tubing from your T's and other fittings. The knife will score the T or other fittings and a leak will definitely be present there. A few of these in your jet and you'll be in trouble. Best way I've found to remove the airline is to use a side cutter or Dykes and pinch it from the side and remove a little of the airline and then pull it off. How ever you do it don't damage the fittings and you'll be golden. I guess this falls under user error which is what causes most problems in anything in life. LOL!
Tim
Tim
04-22-2011, 08:51 PM
#6
My Feedback: (2)
RE: The most common problem with air systems in jets?
I second Tim's comments about not using a knife to remove old air line. My preferred way is to "score" the tubing with a hot soldering iron pointed tip, then the line practically falls off and no scratch marks on the nipples. Scratches will leak.
04-22-2011, 09:11 PM
#7
Thread Starter
RE: The most common problem with air systems in jets?
yeah i built a combat models f-16 and ran into this with the plastic T fittings. I didnt know any better and used a ex-acto knife and it left a little score in the T fitting which allowed the leak. I plan on using metal fittings and will not do that again.
Do they make any kind of tool that gives a nice clean cut? I have seen a few for Festo line cutting would they work on air lines?
If I went Air I wanted to get an all in one system that controls it all so I dont have to do servos and control valve. This would add extra weight and also more room for error. Are these devices reliable? I would guess so but will ask anyway.
Thanks guys this is good stuff some people never learn the basics or learn to crawl before they run. I have been flying for 20 years with helicopters and Giant scale 3D plane and it still amazes me how many people dont take the time to learn how to build and setup there own aircraft.
oh yeah i do you guys use the small screw on fittings for your air lines? i know with robart stuff they they give you small threaded nuts to wo put on over the air line once its installed on the fitting. I always wondered about these and thought they could possible disfigure the line or damage it and cause a leak.
Do they make any kind of tool that gives a nice clean cut? I have seen a few for Festo line cutting would they work on air lines?
If I went Air I wanted to get an all in one system that controls it all so I dont have to do servos and control valve. This would add extra weight and also more room for error. Are these devices reliable? I would guess so but will ask anyway.
Thanks guys this is good stuff some people never learn the basics or learn to crawl before they run. I have been flying for 20 years with helicopters and Giant scale 3D plane and it still amazes me how many people dont take the time to learn how to build and setup there own aircraft.
oh yeah i do you guys use the small screw on fittings for your air lines? i know with robart stuff they they give you small threaded nuts to wo put on over the air line once its installed on the fitting. I always wondered about these and thought they could possible disfigure the line or damage it and cause a leak.
04-22-2011, 09:21 PM
#8
RE: The most common problem with air systems in jets?
i know with robart stuff they they give you small threaded nuts to wo put on over the air line once its installed on the fitting.
04-22-2011, 09:38 PM
#9
RE: The most common problem with air systems in jets?
a possible problem is trunnion blocks getting stuck in lock position ... if necessary, make sure you file the frames / blocks so they can't get stuck locked .. this depends on retract design / geometry often times ...
~V~
~V~
04-23-2011, 09:29 AM
#10
RE: The most common problem with air systems in jets?
- make sure the mounting frames for the retracts are very flat else you can flex the retract when you tighten the mounting bolts down. This can cause problems that are tricky to isolate and might only happen in the air.
- don't use a grease or any liquid for lubrication of the retract mechanism, it attract grit and the resulting gritty paste will wipe out the retract over time.
- I cut all my lines with a special cutter I got from Todd, it seems to help.
- I have used those robart knurled things once or twice, hard to tell if they help or not. I don't use them or safety wire.
- good airline is_critical.....call UP and ask them about airline, they will tell you the straight scoop. I love their airline and use it exclusively.
- Maybe those all in one control unit brick things are bulletproof now (they sure weren't in the beginning and crazy expensive)), I never saw the need for them I use the UP valves (and he give free repairs and crash dmage for life so you really only need to buy a couple for your entire hobby career). I use his for sequencing with doors as well. I cannot imagine those big brick controllers are lighter than a valve and a mini servo, but who knows.
- Don't use a micro servo on the valve, use a nice mini with metal gears if you are going to actuate the valve manually. this can strip nylon gears. Make sure and take that into account, you usually want to be able to actuate the gear with the radio off, but this has become less of an issue with the spread spectrum radios.
- I use the rare earth magnets now on basically every gear door. They are great.
BTW why in the world are you worried about getting flamed for this question??
- don't use a grease or any liquid for lubrication of the retract mechanism, it attract grit and the resulting gritty paste will wipe out the retract over time.
- I cut all my lines with a special cutter I got from Todd, it seems to help.
- I have used those robart knurled things once or twice, hard to tell if they help or not. I don't use them or safety wire.
- good airline is_critical.....call UP and ask them about airline, they will tell you the straight scoop. I love their airline and use it exclusively.
- Maybe those all in one control unit brick things are bulletproof now (they sure weren't in the beginning and crazy expensive)), I never saw the need for them I use the UP valves (and he give free repairs and crash dmage for life so you really only need to buy a couple for your entire hobby career). I use his for sequencing with doors as well. I cannot imagine those big brick controllers are lighter than a valve and a mini servo, but who knows.
- Don't use a micro servo on the valve, use a nice mini with metal gears if you are going to actuate the valve manually. this can strip nylon gears. Make sure and take that into account, you usually want to be able to actuate the gear with the radio off, but this has become less of an issue with the spread spectrum radios.
- I use the rare earth magnets now on basically every gear door. They are great.
BTW why in the world are you worried about getting flamed for this question??
04-23-2011, 12:25 PM
#11
Thread Starter
RE: The most common problem with air systems in jets?
What brand airline is "UP"?
Seems lately being excited and asking some basic questions about different products and thing makes some people mad. I was asking around trying to do my home work on a new area for me and all seem to get is a lot angry birds telling me to use the search function(which is worthless) and stuff like that. Still have had some great responses from people eager to help. Some people dont understand that not everyone can travel all over the country to events and u may be the only person in your area who is trying jets. Heck even if you do have someone in your area not everyone likes to help other people. I use forums for what they are for, learning ,asking questions and just making meaning full discussion topics.
Seems lately being excited and asking some basic questions about different products and thing makes some people mad. I was asking around trying to do my home work on a new area for me and all seem to get is a lot angry birds
telling me to use the search function(which is worthless) and stuff like that. Still have had some great responses from people eager to help. Some people dont understand that not everyone can travel all over the country to events and u may be the only person in your area who is trying jets. Heck even if you do have someone in your area not everyone likes to help other people. I use forums for what they are for, learning ,asking questions and just making meaning full discussion topics.
ORIGINAL: mr_matt
- make sure the mounting frames for the retracts are very flat else you can flex the retract when you tighten the mounting bolts down. This can cause problems that are tricky to isolate and might only happen in the air.
- don't use a grease or any liquid for lubrication of the retract mechanism, it attract grit and the resulting gritty paste will wipe out the retract over time.
- I cut all my lines with a special cutter I got from Todd, it seems to help.
- I have used those robart knurled things once or twice, hard to tell if they help or not. I don't use them or safety wire.
- good airline is_critical.....call UP and ask them about airline, they will tell you the straight scoop. I love their airline and use it exclusively.
- Maybe those all in one control unit brick things are bulletproof now (they sure weren't in the beginning and crazy expensive)), I never saw the need for them I use the UP valves (and he give free repairs and crash dmage for life so you really only need to buy a couple for your entire hobby career). I use his for sequencing with doors as well. I cannot imagine those big brick controllers are lighter than a valve and a mini servo, but who knows.
- Don't use a micro servo on the valve, use a nice mini with metal gears if you are going to actuate the valve manually. this can strip nylon gears. Make sure and take that into account, you usually want to be able to actuate the gear with the radio off, but this has become less of an issue with the spread spectrum radios.
- I use the rare earth magnets now on basically every gear door. They are great.
BTW why in the world are you worried about getting flamed for this question??
- make sure the mounting frames for the retracts are very flat else you can flex the retract when you tighten the mounting bolts down. This can cause problems that are tricky to isolate and might only happen in the air.
- don't use a grease or any liquid for lubrication of the retract mechanism, it attract grit and the resulting gritty paste will wipe out the retract over time.
- I cut all my lines with a special cutter I got from Todd, it seems to help.
- I have used those robart knurled things once or twice, hard to tell if they help or not. I don't use them or safety wire.
- good airline is_critical.....call UP and ask them about airline, they will tell you the straight scoop. I love their airline and use it exclusively.
- Maybe those all in one control unit brick things are bulletproof now (they sure weren't in the beginning and crazy expensive)), I never saw the need for them I use the UP valves (and he give free repairs and crash dmage for life so you really only need to buy a couple for your entire hobby career). I use his for sequencing with doors as well. I cannot imagine those big brick controllers are lighter than a valve and a mini servo, but who knows.
- Don't use a micro servo on the valve, use a nice mini with metal gears if you are going to actuate the valve manually. this can strip nylon gears. Make sure and take that into account, you usually want to be able to actuate the gear with the radio off, but this has become less of an issue with the spread spectrum radios.
- I use the rare earth magnets now on basically every gear door. They are great.
BTW why in the world are you worried about getting flamed for this question??
04-23-2011, 01:04 PM
#12
RE: The most common problem with air systems in jets?
Ultra Precision
http://www.up-1.com/products.html
If you want to search this forum try goole search it is much better...something like:
ultra precision site:rcuniverse.com
http://www.up-1.com/products.html
If you want to search this forum try goole search it is much better...something like:
ultra precision site:rcuniverse.com
04-23-2011, 01:14 PM
#13
RE: The most common problem with air systems in jets?
Error: bad design!
Incorrect o-ring selection, incorrect cylinder sizing, incorrect cylinder placement, inappropriate locking mechanism, list goes on and on.
A properly lubricated oring should last 30 years.
Incorrect o-ring selection, incorrect cylinder sizing, incorrect cylinder placement, inappropriate locking mechanism, list goes on and on.
A properly lubricated oring should last 30 years.
04-23-2011, 01:24 PM
#14
RE: The most common problem with air systems in jets?
I agree on good retracts I have never really seen leaks in the cylinder. I did once on a BVM retract (RARE) and they fixed it, traced it to an out of round cylinder. My guess is that is most of the problem with these poor cylinders coming out on arfs, they are boring the cylinders out of round.
04-23-2011, 06:03 PM
#17
Thread Starter
RE: The most common problem with air systems in jets?
yeah for the doors being closed i guess the wind causes vibration which over time could damage the gear door cylinders
04-23-2011, 07:36 PM
#18
RE: The most common problem with air systems in jets?
ORIGINAL: FenderBean
yeah for the doors being closed i guess the wind causes vibration which over time could damage the gear door cylinders
yeah for the doors being closed i guess the wind causes vibration which over time could damage the gear door cylinders
OK I can see some of what you were talking about earlier with the flaming...
If there are vibrating gear door cylinder failures I have not heard of it!
For me, the magnets are just there to keep the doors shut. I first used them years ago on a bobcat for the nosegear doors.
04-23-2011, 08:12 PM
#19
Thread Starter
RE: The most common problem with air systems in jets?
I was kind of worried that they could cause I bind issue, but if you off set them a little no worries.
04-24-2011, 02:50 AM
#20
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RE: The most common problem with air systems in jets?
i always use metal fittings so all that i do when having to remove air tubing is use a cigarette lighter and warm up the tubing at the fitting to soften it
