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RE: Jetlegend Mig 29 Fulcrum
1 Attachment(s)
John/Rob
I checked my board and its capacitor is a 10u 35volt. I am not sure if this is the size fitted to your boards when you got them, as mentioned my units are at least 12 months old. I had a look at one of my Eurokit units and it is fitted with a 10u 25 volt, so I am not sure which is the right size to use other than the other guy in Aus refitted the 35 volt unit and it worked fine!!! The other photo's show the Festo valve that I have used for the leg locks. I have also included a "hydraulic circuit" of how it works but it will be confusing if you are not in this game. Basically you can see the relationship of the Festo valve in regard to the cylinder and that you use the line the extends the cylinder to "pilot open" the check valve and let the oil out, otherwise the cylinder will stay in that position forever.....These Festo valves are about $ 65 each here in Aus but will make this JL undercarriage work properly. You need to set them up as close as you can to each of the leg cylinders. |
RE: Jetlegend Mig 29 Fulcrum
Shane,
Thanks for the info. That makes sense now, I was wondering what actually actuated the NRV's but I can see you have TEE'd off from the gear up line. I should get my NRV's today or tomorrow. They are about £22.00 each here in UK. John |
RE: Jetlegend Mig 29 Fulcrum
John,
Have to say I'm very frustrated with the UMS controller. After the first one burned out I ordered 2 replacements; received them yesterday. Burned both out in exactly the same area as before. The second burnout was without the servo wire that runs the hydraulic controller connected. I just slid the pin manually. Didn't make any difference as they both smoked and got red hot in the same area as before. I accept that I may be repeating the same problem to cause the same result, however, this part must be under-designed to cause so many burnouts around the world. Mine aren't the first and surely won't be the last. John, you switched to an accumulator system with a micro-switch. Can you please describe it in more detail here so that i can emulate it? I'm very disappointed with the UMS system as the hydraulic valve is real sticky and I've burned out 3 controllers. All I've gotten out of the system that works like its supposed to are 3 Festo valves, a tank and a pump. Not good for what it cost. I've ordered a new hydraulic valve and controller from Eurokit. We'll see if their system is any better than UMS's. By the way, Yang of JL fame has purportedly sent me the upgraded parts for the landing gear system. Did you catch the phrase "upgraded"? The charge is $40 for the upgrade as he maintains the original system works just fine and these new parts are customer requested upgrades. The PR fiasco at Jet Legend continues unabated! My dealer agreed to split this cost with me so the upgrades will only cost $20. Thank you Monica. As always, your help and Bart's experiences are appreciated. Regards, Rob F15driver |
RE: Jetlegend Mig 29 Fulcrum
Does anyone know which parts were upgraded in the original LG and how ?
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RE: Jetlegend Mig 29 Fulcrum
1 Attachment(s)
HI Rob,
Sorry to hear about your woes. I too purchased two extra controllers. I put them on the model to see if they were more reliable than the first. The first controller was inconsistent, It would sometimes do a full cycle and then sometimes stop half way through. I changed to the other controller and this has worked correctly every time. The accumulator system was made for me by Mick Burrell, here in the UK. It is made from a robart undercarriage cylinder, with a strong spring fitted inside and a 90degree festo fitted on one end. As the pressure rises in the system the accumulator piston is forced out and eventually pushes the microswitch which is wired so the pump stops running. The only variable is the rating of the spring which dictates the pressure in the system. My model will stand for about 24hrs but then starts to go spongy. It is probably as good as a great many air systems but without up or down locks it needs to be much better. I am now in the process of getting new pistons manufactured to eliminate possible seepage past the glued up holes. As for charging for an "upgrade" I'll wait and see what happens this end. I wouldn't even like to begin to count the time, money and effort I have thrown into getting this Mig reliable. The original system was not fit for the purpose, eventually it would let you down and looking at the thin fuz and underhanging air intakes there would be not a lot left from a wheels up landing. John |
RE: Jetlegend Mig 29 Fulcrum
ORIGINAL: F15driver Have to say I'm very frustrated with the UMS controller. After the first one burned out I ordered 2 replacements; received them yesterday. Burned both out in exactly the same area as before. The second burnout was without the servo wire that runs the hydraulic controller connected. I just slid the pin manually. Didn't make any difference as they both smoked and got red hot in the same area as before. I accept that I may be repeating the same problem to cause the same result, however, this part must be under-designed to cause so many burnouts around the world. Mine aren't the first and surely won't be the last. My UMS is still in the box. Will adding a fuse somewhere avoid the burn-out? any ideas what amperage it can be? I recognize that if the fuse blows it means the retract cycle is not completed... Thanks |
RE: Jetlegend Mig 29 Fulcrum
Edgar,
I think the problem is an undersized capacitor. A fuse would probably blow before the capacitor melted down but that wouldn't enable the retracts. A friend is looking into repairing one of my control boxes with a 35 volt capacitor; don't know how many other components were scorched in the meltdown. I'll let you know if we have any luck. Ian, have you tried your UMS system yet? The pistons you machined for me are working just fine, not leaking past the o-rings at all. On my work bench I can plug the battery directly into the pump and move the retracts either up or down with no problem. There are still issues with the hydraulic valve - it is still way too sticky even after cleaning and greasing it. I've got a different one on order from Eurokit as well as a new control box from them. Hopefully these will work better than UMS's versions. Expect delivery within another week or so. Will post results then. Regards, F15driver |
RE: Jetlegend Mig 29 Fulcrum
UMS Comments and other gear issues.
Bart and John, would like to learn more about the Festo locking valves on your gear set-up, Festo part #'s and the by-pass method used. Getting a solid lock looks like it is necessary as my legs still have a little sponginess, particularly the two mains. The nose gear seems really stiff in the extended position. Edgar and Ian, I've been in email contact with UMS about all three of my control boards burning out and they responded that, yes, the capacitor is the villain and they offered to send me new, better quality capacitors to replace the ones in my failed control boards. The problem is, two of my boards are so fried that all other components in the immediate area were fried as well. I've asked them to replace the control boards but have not heard back from them yet. What I would do, before you use your board, is go to a Radio Shack store and buy a new capacitor and install it yourself. I put one in one of my failed units and it works just fine and cost less than $2.00. Its called a 10uF Electrolytic Capacitor, part # 272-1025. Its rated at 35 volts max. Just a suggestion but the probability that your control board will fry is quite high unless you replace this capacitor which UMS effectively confirmed to me to be of inferior quality. Got a new hydraulic valve from Eurokit yesterday and set it up on my test stand with the retracts. Just like the UMS valve, the Eurokit valve slides very sticky like when under pressure. I've concluded this is going to be a problem regardless of the valve used. Will just need to operate the valve with a strong servo. Look forward to your responses. Regards, Rob F15driver |
RE: Jetlegend Mig 29 Fulcrum
ORIGINAL: F15driver Edgar and Ian, I've been in email contact with UMS about all three of my control boards burning out and they responded that, yes, the capacitor is the villain and they offered to send me new, better quality capacitors to replace the ones in my failed control boards. The problem is, two of my boards are so fried that all other components in the immediate area were fried as well. I've asked them to replace the control boards but have not heard back from them yet. What I would do, before you use your board, is go to a Radio Shack store and buy a new capacitor and install it yourself. I put one in one of my failed units and it works just fine and cost less than $2.00. Its called a 10uF Electrolytic Capacitor, part # 272-1025. Its rated at 35 volts max. Just a suggestion but the probability that your control board will fry is quite high unless you replace this capacitor which UMS effectively confirmed to me to be of inferior quality. Thanks for the advice! I will go ahead and replace the capacitor (my Mig-29 arrives today). If I understand the capacitor change will take care of the electronics. A strong servo takes care of the valve being hard to operate. Is there anything else?( I have to go back and re-read the thread to make sure... think there was a suggestion to add a check valve to mitigate the sponginess). Thanks again and Happy Holidays |
RE: Jetlegend Mig 29 Fulcrum
does anyone know what JL changed in their Mig-29 LG ? perhaps the new gear actually works ?
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RE: Jetlegend Mig 29 Fulcrum
Also, can anyone please list all the servos required for the MIG-29 and what size are they ?
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RE: Jetlegend Mig 29 Fulcrum
i3dm,
Haven't received my "upgraded" modifications from JL yet so can't comment on what they look like nor whether or not they fix the problem with the gear. As far as servos go, I've installed 8711's on the elevators and flaps, 8231's on the ailerons and 3451's on the rudders. Thats 8 servos and will need a strong servo if using the hydraulic system such as the 8411. Remaining servos would be nose gear steering, 8411 here and whatever you would use for wheel brakes, depending on the system employed. Hope this helps. Edgar, am awaiting comments from Bart and John regarding the check valve system they've employed to cut way down on the sponginess of the gear. I think my gear is probably alright as is, but firmer is better! Hope this helps, Rob F15driver |
RE: Jetlegend Mig 29 Fulcrum
Hi Rob,
I've been let down by UPS on the delivery of my check valves. I ordered them on 6th December and I am still awaiting delivery having received loads of excuses about the weather we are having here and Christmas rush. It will probably now be in the new year till I try them. I am having new pistons machined to eliminate any possible problem there but I still have a problem in that the cylinder walls are scored from where the ball bearings have rubbed. I have been getting on, in the mean time with finishing my FB T33 and will start on the Mig again in a couple of weeks. John |
RE: Jetlegend Mig 29 Fulcrum
John,
Well, the good news in all of this is that you have a really cool plane to build in the FB T33! What check valves did you order for the Mig? In Bart's set-up it looks like they're in line in a manifold arrangement. Part #'s would be really helpful if you have them. Best regards and merry X-mas! Rob |
RE: Jetlegend Mig 29 Fulcrum
Hi Rob,
Merry Xmas to you. The festo non-return valves you need are HGL M5 QS-4. You need three fixed in the down line near the cylinders. At the moment my model is like yours in that it is rock solid on the nose gear but a bit spongy on the mains. After about a day it looses pressure and starts to go soggy on the mains. I hope the fitting of the non-return valves and my new pistons(machined from solid) will make it perfect. I've had the T33 for a while but not been able to fly it because the factory asked owners not to fly them until they had supplied everyone with new wings. They have arrived now so it is just a matter of changing the servos etc over and it will be ready to maiden. Weather here is not good for flying, so hopefully I can get everything ready for an early start to the new year. John |
RE: Jetlegend Mig 29 Fulcrum
Just one point guys regarding the capacitor. If you replace the electrolytic with another electrolytic do ensure that you observe the correct polarity. If you do not you will not have to wait until you put it under excessive load for it to go bang! ou should normally find a + sign beside one of the terminals.
My second suggestion is that you use a retract servo to drive the valve. As well as being low geared and powerful, a properly designed retract servo switches itself off after a set period to avoid being burnt out if the mechanism jams. This in turn prevents flattening of your battery. Conversly a digital servo will burn out quickly if it stalled and drags a huge amount of current out of the battery in the meantime. I will wait and see how mine works when it arrives (do not have a delivery date yet) before deciding on hydraulics. Merry Christmas, John |
RE: Jetlegend Mig 29 Fulcrum
ORIGINAL: Edgar Perez ORIGINAL: F15driver Edgar and Ian, I've been in email contact with UMS about all three of my control boards burning out and they responded that, yes, the capacitor is the villain and they offered to send me new, better quality capacitors to replace the ones in my failed control boards. The problem is, two of my boards are so fried that all other components in the immediate area were fried as well. I've asked them to replace the control boards but have not heard back from them yet. What I would do, before you use your board, is go to a Radio Shack store and buy a new capacitor and install it yourself. I put one in one of my failed units and it works just fine and cost less than $2.00. Its called a 10uF Electrolytic Capacitor, part # 272-1025. Its rated at 35 volts max. Just a suggestion but the probability that your control board will fry is quite high unless you replace this capacitor which UMS effectively confirmed to me to be of inferior quality. Thanks for the advice! I will go ahead and replace the capacitor (my Mig-29 arrives today). If I understand the capacitor change will take care of the electronics. A strong servo takes care of the valve being hard to operate. Is there anything else?( I have to go back and re-read the thread to make sure... think there was a suggestion to add a check valve to mitigate the sponginess). Thanks again and Happy Holidays |
RE: Jetlegend Mig 29 Fulcrum
Rob/John
UMS controller capacitor seems to be the culprit as I had suspected earlier, all of my units are at least 12 months old and have never failed but they are also fitted with the 10u 35 volt caps as standard. The UMS valve (in my cases) really does not seem to take much power to move. I tend to use the Bluebird thin wing digital servo that is rated at 5 kgs/cm. The piano wire link I use from the servo arm to the valve spool is fitted right next to the hub of the servo horn and maybe 10 mm (1 cm) distance out from the horn screw which give a theoretical force of 5 kgs. Because the spool movement is so short, you need to keep the servo arm attachment as short as possible anyway. I like the idea of John Mac about using the retract servo, I might try that on the F14 when I fit that out. As mentioned earlier, once you fit the Festo Pilot Check Valves your main will become rock hard, just try and remember to put some safety wire or similar on the tube where ever it goes over a barbed fitting. The reason the mains feel softer compared to the nose is the angle the cylinder sits on and therefore the force ratio it can achieve. With the Festo valves, my Mig sits on its mains for literally weeks (and has no reason to ever leak down), I actually end up with flat spots on the tires.... As for the manifold arrangement of the valve, it is already set up with the 3 ports, I also fitted 4 mm to 3 mm reducers on each port to allow the tube fit up. If you have a look at my earlier post at the top of this page there are 5 photo's (scroll across), I am not sure why but the 5th photo seems to be just an icon that you need to click on, this photo is actually the hydraulic circuit showing just how these valves are set up and work, I hope you guys can see this ok, if not let me know and I will try and post again. Like most of you, I would be really keen to see if JL have resolved this problem although it seems that no one has any idea if the "upgrade" even exists. I was going to buy the SU27 and although I know how to fix the gear (it has the same setup as the Mig), in principal I won't buy it until I know they have addressed the issue because from where I sit they continue to sell aircraft with UC that is guaranteed to fail and they don't care. I hope you all have a merry Christmas and behave yourselves, unfortunately I have to tell you that during this holiday season I will have to fly my Mig in this glorious Aussie weather on retracts that work just oh so sweet. |
RE: Jetlegend Mig 29 Fulcrum
i was told by JL that the upgrade does exist now indeed, lets wait and see what it includes.
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RE: Jetlegend Mig 29 Fulcrum
What a shame, you must pay for an "upgrade" to get it to work.
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RE: Jetlegend Mig 29 Fulcrum
ORIGINAL: Jascat100 edgar. How long did you have to wait for your Mig29? I ordered mine 10th November & have not heard when it will be delivered. Cannot get any answers to my e-mails. He provides great service.:D |
RE: Jetlegend Mig 29 Fulcrum
Hi Guys,
I've been trying to get an answer on the upgrades for nearly 2 months, yet I get no reply. Funnily enough I did get a normal reply to a Merry Christmas Email....... I'm thinking of trying smoke signal or carrier pigeon as my next option!! I'll keep trying let you know if get anything back. |
RE: Jetlegend Mig 29 Fulcrum
ORIGINAL: Jeremy_D Hi Guys, I've been trying to get an answer on the upgrades for nearly 2 months, yet I get no reply. Funnily enough I did get a normal reply to a Merry Christmas Email....... I'm thinking of trying smoke signal or carrier pigeon as my next option!! I'll keep trying let you know if get anything back. I reckon Yang is waiting for things to blow over!! A smart entrepreneur like yourself could do well to supply an aftermarket kit of gear already modified along with all the hydraulics, mounts & hardware fully tested, customers could order the plane without gear and I am sure it would end up being only a small additional cost for something that works. Happy to help if you need a hand. |
RE: Jetlegend Mig 29 Fulcrum
Bart,
Thanks for the explanation on the icon showing the hydraulic setup. in researching the Festo valve in their catalog here in the US, their picture shows the manifold with two valves facing downward like yours but no valve on the end. I gather you've added this Festo connection. Do you have a part # for it as well? Also can you show exactly how you connect the hydraulic lines to these 3 valves? Are the 4mm/3mm reducers installed just below the 2 downward pointed Festos? Sorry for all the questions but as you pointed out earlier, one needs to be in this line of business for it to make sense. Thanks for your help. Rob |
RE: Jetlegend Mig 29 Fulcrum
Also where did you guys buy you HGL M5 QS-4 manifolds from? I have found plenty of data on them but no easy source to order them from.
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