Carbon T-28
10-16-2015, 06:09 PM
#77
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Two of my retracts stopped working. Left wing and nose gear. My RC guru friend brought over a spare radio and receiver and tested everything out, including the harness. He determined that it is definitely the retracts, which he said are FMS retracts. I haven't called eflite yet. My friend said I'd be better off buying some decent retracts instead of getting more of these cheap retracts. Are there any quality drop in replacement retracts that will work with little to no modification?
10-17-2015, 01:15 PM
#78
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My friend did some research and couldn't find any better replacements that would fit, so I called eflite and they are sending me 3 new retracts. The guy I talked to, Jordan, said I'm not the first to have this issue.
10-18-2015, 07:59 AM
#79
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How many flights did you have on it and what type of surface do you mostly fly off of? Grass/paved?
I am among those who have had a retract fail. Not fun, at least mine happened on the ground so not damage to the plane.
I am among those who have had a retract fail. Not fun, at least mine happened on the ground so not damage to the plane.
10-18-2015, 04:03 PM
#80
All I seen was probable with those 2 and the 3rd that sounded like a reversed aileron, what I'm asking is have you heard anything definite, also where did you get this info. .?
From the sounds of it for all we know could also have been the elevator clevis on the 1st one. ..all speculation
Still good advice on the separate bec and battery, should be standard on a plane this size
From the sounds of it for all we know could also have been the elevator clevis on the 1st one. ..all speculation
Still good advice on the separate bec and battery, should be standard on a plane this size
10-18-2015, 08:22 PM
#81
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The plane had 3 flights on it. The first two were landed by my RC guru friend, and I landed the third. My friend is very good. He has 77 planes and can do a rolling circle. He landed it without flaps. My landing was with flaps and my friend remarked that it was better than his landings. All three landings were on pavement. These failures also occurred on the ground. It seems weird that two gears would spontaneously fail in between flights.
Another friend of mine, who is an engineer, took the gear apart and said the plastic stops that prevent the bearing from traveling too far past the switch appeared to be melted, so it travelled too far and that's why the gear got stuck in the retracted position. I have been storing the plane in a trailer that is not climate controlled, and so I wonder if the metal bearing got hot repeatedly and melted that stop to the point it no longer did its job. I'd be curious to hear if any spontaneous, on the ground, gear failures occurred for people who store the plane in a climate controlled environment, so it doesn't get hot.
Another friend of mine, who is an engineer, took the gear apart and said the plastic stops that prevent the bearing from traveling too far past the switch appeared to be melted, so it travelled too far and that's why the gear got stuck in the retracted position. I have been storing the plane in a trailer that is not climate controlled, and so I wonder if the metal bearing got hot repeatedly and melted that stop to the point it no longer did its job. I'd be curious to hear if any spontaneous, on the ground, gear failures occurred for people who store the plane in a climate controlled environment, so it doesn't get hot.
10-18-2015, 09:11 PM
#82
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I have taken my retract apart twice now as the retract pinion moves to far pass the micro switch .I turned the pinion back on the screw till it fit back on the micro switch and it worked fine.It seems to happen when the retract moves to the lock position.Horizon as sent me another retract and a new servo and ext for elevator that went to full up on take off on my maiden,I asked Horizon what torque specs were on that servo and they nothing on it, so I replaced it with a savox servo.I ve got 4 flights on mine and it is one sweet flyer,the flaps work awesome.I am going to run a separate battery for my retracts as the other guys spoke about.
10-19-2015, 06:57 AM
#83
My Feedback: (9)
I put fuses on mine and on flight 2 burned out a 2amp fuse, flight 3 burned out a 3amp fuse and the nose gear was toast. once I got the new retract units I took the bad unit apart. a 1.5, 3 and 4.5 voltage source would not turn over the motor when it was out of the retract, it also smelled burnout. after reassembly I plugged it in the plane on the bench and it blew a 4 amp fuse but not a 5 amp because the RX rebooted before the fuse blew. im pretty sure what is going on here is the values of the circuit board components are drifting with age. as they drift the over amp cutoff changes, if it gets high enough to burn out the motor it can get ugly.
the good news is if you go 90 days w/o a failure the components will have stabilized. so if they survive that period they are good to go.
my nose gear servo quit about 6 flights ago I centered it unplugged it and have been using up Elevator rudder and throttle to turn and it works fine so far. I have not tested it in higher than 20 mph wind yet but we will.
Joe
the good news is if you go 90 days w/o a failure the components will have stabilized. so if they survive that period they are good to go.
my nose gear servo quit about 6 flights ago I centered it unplugged it and have been using up Elevator rudder and throttle to turn and it works fine so far. I have not tested it in higher than 20 mph wind yet but we will.
Joe
Last edited by paladin; 10-19-2015 at 06:59 AM.
11-08-2015, 05:53 PM
#87
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Got my two new retracts installed and flew it today. Landed it nicely enough for spectator applause, but on then testing the retracts, the one I did not replace in the right wing would not cycle. Called eflite and they are sending me the third gear. If they break again, I plan to convert it to a tail dragger with some wire gear.
11-16-2015, 08:27 AM
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My third replacement retract was DOA. It didn't even try to cycle. To eflite's credit they are sending me yet another one, but said if I ask for any more, they will require me to send in all the bad ones. I think they are getting low on the replacements retracts. At first they said they didn't have any available to send.
11-29-2015, 07:08 PM
#90
My Feedback: (20)
Just found this thread today after crashing my big foamy T-28 and searching for answers.
I had 6 flights before today. Stock setup. No hard flying. Most of my flying has been 1/2 power patterns and touch and goes since it flies so well. It was one of the best flying planes I have flown in 50 years of this hobby. Sport, Scale, IMAC, and Turbines. The T-28 was supposed to be a low stress fun flier with low maintenance. It was for 7 flights.
Today weather was perfect in SC. Flight #1 was ok. With fresh battery, flight #2 lasted about 2 min. Take off followed by 1/2 power slow cruising the pattern with gear up and 1/2 flaps. I felt like I needed more throttle angle to maintain power to hold altitude and speed. I even looked down at the throttle stick to see where it was. It was just above 50% which was a little higher than normal. Just after making a shoulder level slow pass left to right about 10 feet away, with a slight breeze in my face, I could smell an electrical burning smell. It was also smelled by another pilot just to my left.
Just then voice telemetry announced a RX voltage warning at 3.7v (down from normal 5v). I immediately started a left turn to land down wind. Half way through the turn, 3-5 sec later, voice telemetry announced RX voltage 0.0v. The T-28 immediately pitched up into an accelerated stall with motor still at power, pitched over on its back nearly completing a loop, then hit the ground about 30 degrees nose low nearly wings level still producing power. I had no control at all. I never had time to drop the gear. The nose was broken off, cowl busted up, prop broke, gears are lose, wings separated about 1/2", not sure what else. Still have not had time to take it all apart and see.
I ran to the crash site, which was on the runway, thinking I had a LIPO fire from the smell. No fire. Opened the canopy hatch and burning smell was strong. No smoke any where. Battery was cool. No flight controls worked. Telemetry was reading input voltage 22.4v and Rx voltage 0.0v Battery was later checked at 75% charge.
After talking with the guys and reading this thread here is what I think happened. Speculation right now.
After take off on the 2nd flight I retracted the gear. I left the flaps at 1/2 where they were for take off. I speculate the gear jammed somewhere and started cooking the BEC. Not sure why but it seemed like I needed more throttle stick angle to produce required power to hold altitude and speed. On my second pass you could smell the BEC cooking. As it cooked the BEC voltage started to drop, went below telemetry warning threshold, and then failed completely.
As a result the receiver shut down and all flight control surfaces froze in current position. This caused the elevator angle to be stuck in some "nose up" position because RX power failed when I was trying to make a tight turn. This caused the power on accelerated stall and loop. This elevator position then allowed the nose to nearly be level before impact. The T-28 did not snap or roll at all.
Tomorrow I will take everything apart and check the ESC and BEC. I will report back.
Gary
I had 6 flights before today. Stock setup. No hard flying. Most of my flying has been 1/2 power patterns and touch and goes since it flies so well. It was one of the best flying planes I have flown in 50 years of this hobby. Sport, Scale, IMAC, and Turbines. The T-28 was supposed to be a low stress fun flier with low maintenance. It was for 7 flights.
Today weather was perfect in SC. Flight #1 was ok. With fresh battery, flight #2 lasted about 2 min. Take off followed by 1/2 power slow cruising the pattern with gear up and 1/2 flaps. I felt like I needed more throttle angle to maintain power to hold altitude and speed. I even looked down at the throttle stick to see where it was. It was just above 50% which was a little higher than normal. Just after making a shoulder level slow pass left to right about 10 feet away, with a slight breeze in my face, I could smell an electrical burning smell. It was also smelled by another pilot just to my left.
Just then voice telemetry announced a RX voltage warning at 3.7v (down from normal 5v). I immediately started a left turn to land down wind. Half way through the turn, 3-5 sec later, voice telemetry announced RX voltage 0.0v. The T-28 immediately pitched up into an accelerated stall with motor still at power, pitched over on its back nearly completing a loop, then hit the ground about 30 degrees nose low nearly wings level still producing power. I had no control at all. I never had time to drop the gear. The nose was broken off, cowl busted up, prop broke, gears are lose, wings separated about 1/2", not sure what else. Still have not had time to take it all apart and see.
I ran to the crash site, which was on the runway, thinking I had a LIPO fire from the smell. No fire. Opened the canopy hatch and burning smell was strong. No smoke any where. Battery was cool. No flight controls worked. Telemetry was reading input voltage 22.4v and Rx voltage 0.0v Battery was later checked at 75% charge.
After talking with the guys and reading this thread here is what I think happened. Speculation right now.
After take off on the 2nd flight I retracted the gear. I left the flaps at 1/2 where they were for take off. I speculate the gear jammed somewhere and started cooking the BEC. Not sure why but it seemed like I needed more throttle stick angle to produce required power to hold altitude and speed. On my second pass you could smell the BEC cooking. As it cooked the BEC voltage started to drop, went below telemetry warning threshold, and then failed completely.
As a result the receiver shut down and all flight control surfaces froze in current position. This caused the elevator angle to be stuck in some "nose up" position because RX power failed when I was trying to make a tight turn. This caused the power on accelerated stall and loop. This elevator position then allowed the nose to nearly be level before impact. The T-28 did not snap or roll at all.
Tomorrow I will take everything apart and check the ESC and BEC. I will report back.
Gary
11-29-2015, 07:43 PM
#91
My Feedback: (8)
Wish you had found the thread earlier. I followed the suggestion to use an external BEC (Castle 20A) before my first flight just because others had reported problems. Also did a flap hinge line fix and upgrade of the servo linkages. So far so good. Around 30 flights so far.
I do have a rather annoying issue that I have not seen discussed in any forums. There is a plastic tab on the plastic strut cover where the upper gear door attaches to the strut that broke off. Used CA to repair it but it broke again two flights later. OH! Guess what?!?! You can't order just a replacement strut cover from Horizon. They only sell the entire set of struts and doors for nearly $70 bucks!
I do have a rather annoying issue that I have not seen discussed in any forums. There is a plastic tab on the plastic strut cover where the upper gear door attaches to the strut that broke off. Used CA to repair it but it broke again two flights later. OH! Guess what?!?! You can't order just a replacement strut cover from Horizon. They only sell the entire set of struts and doors for nearly $70 bucks!
11-30-2015, 07:35 PM
#92
My Feedback: (20)
Post crash analysis revealed cause of my crash.
The nose gear steering servo jammed and burned up causing a short of servo leads, loss of RX power and crash. Cause of the jam was the poor design and materials of the steering linkage to nose gear.
When retracted the steering servo continues to move the steering pushrod which is attached to an aluminum block. The block is supposed to slide on a metal steering arm mounted to the nose gear strut. This aluminum block has no sleeve or bushing so it is metal to metal sliding. In my case the slightest push on the steering pushrod when retracted would tilt the block on the rod slightly causing an immediate bind and jammed servo. After a while the steering servo over heated, melted the case, shorted the wires together, melted the foam under the battery mount plywood where the wires ran to the RX and fried the RX. Done deal.
In phone conversations today I was told about another T-28 that was lost for the same reason. It was not repairable.
I plan to repair mine. With a new receiver, my ESC still works, and all other servos and all three gear still work. I am repairing the cowl with RC-56 glue and fiberglass cloth. I am repairing the foam cracks with hysol and 5 min epoxy. I am replacing the BEC with a dedicated RX battery, replacing all clevis with 2-56 links, and rehinging the flaps with real hinges. My foam flap hinges are both cracked and one is 1/3 split off. I have already drilled out the aluminum block and installed a plastic sleeve inside. Now it slides very easy and does not bind. The sleeve was a piece of blue Sullivan Golden Rod outer sleeve. Drill was a #7 numbered drill and hysol to hold in the blue plastic sleeve. New servo is already ordered.
Another issue I had was one of the lower gear door mounts broke and the door would bend back from landing and takeoff in grass. I just took the lower doors off. It looks fine. Beats $70 bucks for it to break again.
I was told to call HH and complain. I won't waste my time with them. They will never take responsibility for the poor design.
I love the way the T-28 flies. I have a Model Sound system from Dymond USA that I will install and make it sound real. I tested it today. Sound like a big radial engine on my bench.
Hope this may help others before they have a T-28 wreck. Great airplane just cheap parts and poor design. It would not take much for HH to fix all the issues mentioned in this thread. I mostly fly turbines and I wanted the T-28 because it looks and flies great and was supposed to be easy and reliable.
Hopefully it will get that way soon.
The nose gear steering servo jammed and burned up causing a short of servo leads, loss of RX power and crash. Cause of the jam was the poor design and materials of the steering linkage to nose gear.
When retracted the steering servo continues to move the steering pushrod which is attached to an aluminum block. The block is supposed to slide on a metal steering arm mounted to the nose gear strut. This aluminum block has no sleeve or bushing so it is metal to metal sliding. In my case the slightest push on the steering pushrod when retracted would tilt the block on the rod slightly causing an immediate bind and jammed servo. After a while the steering servo over heated, melted the case, shorted the wires together, melted the foam under the battery mount plywood where the wires ran to the RX and fried the RX. Done deal.
In phone conversations today I was told about another T-28 that was lost for the same reason. It was not repairable.
I plan to repair mine. With a new receiver, my ESC still works, and all other servos and all three gear still work. I am repairing the cowl with RC-56 glue and fiberglass cloth. I am repairing the foam cracks with hysol and 5 min epoxy. I am replacing the BEC with a dedicated RX battery, replacing all clevis with 2-56 links, and rehinging the flaps with real hinges. My foam flap hinges are both cracked and one is 1/3 split off. I have already drilled out the aluminum block and installed a plastic sleeve inside. Now it slides very easy and does not bind. The sleeve was a piece of blue Sullivan Golden Rod outer sleeve. Drill was a #7 numbered drill and hysol to hold in the blue plastic sleeve. New servo is already ordered.
Another issue I had was one of the lower gear door mounts broke and the door would bend back from landing and takeoff in grass. I just took the lower doors off. It looks fine. Beats $70 bucks for it to break again.
I was told to call HH and complain. I won't waste my time with them. They will never take responsibility for the poor design.
I love the way the T-28 flies. I have a Model Sound system from Dymond USA that I will install and make it sound real. I tested it today. Sound like a big radial engine on my bench.
Hope this may help others before they have a T-28 wreck. Great airplane just cheap parts and poor design. It would not take much for HH to fix all the issues mentioned in this thread. I mostly fly turbines and I wanted the T-28 because it looks and flies great and was supposed to be easy and reliable.
Hopefully it will get that way soon.
12-01-2015, 03:55 AM
#93
My Feedback: (20)
After re reading this thread I am pretty sure that my BEC went to thermal shut down when the steering servo was jamming against the NG steering arm when the gear was up. Hence the RX shut down and crash. This fits the smell, telemetry warnings, and crash as they happened exactly. This also explains why the BEC still works but the RX got fried along with the NG servo and wires.
After my plastic bushing steering arm fix I don't think the servo will jam again but I am worried about the electric gear causing another fail if the gear is powered by the RX power bus. The fix may be to put the gear on the separate battery as mentioned earlier. However, with out the steering linkage fix this would not protect the flight controls if the steering servo is still on the RX power bus.
A separate fix would be to disable the steering servo when gear up since it does not bind gear down and keep the gear on the separate battery.
Repairs should be complete today but still have to wait for a new steering servo.
Gary
After my plastic bushing steering arm fix I don't think the servo will jam again but I am worried about the electric gear causing another fail if the gear is powered by the RX power bus. The fix may be to put the gear on the separate battery as mentioned earlier. However, with out the steering linkage fix this would not protect the flight controls if the steering servo is still on the RX power bus.
A separate fix would be to disable the steering servo when gear up since it does not bind gear down and keep the gear on the separate battery.
Repairs should be complete today but still have to wait for a new steering servo.
Gary
12-01-2015, 01:40 PM
#95
My Feedback: (9)
viper sorry to here of your loss!
my steering servo stopped working around flight 5. I unplugged it and adjusted the linkage so the nose wheel was straight and have 10 flights on it that way. using full up elevator and throttle it turns very well even in some wind (up to 20mph, have not tried higher yet). if I replace it I will use a servo capable of the load.
Joe
my steering servo stopped working around flight 5. I unplugged it and adjusted the linkage so the nose wheel was straight and have 10 flights on it that way. using full up elevator and throttle it turns very well even in some wind (up to 20mph, have not tried higher yet). if I replace it I will use a servo capable of the load.
Joe
12-01-2015, 05:37 PM
#96
My Feedback: (20)
T-28 repairs and modifications completed today. All thats left to do is to reinstall radio, motor, ESC and wire it all up etc. Still waiting on new steering servo and prop. Ordered a Master AirScrew 14 x 7 3 blade. I will check the amp draw on the motor before flying.
I will use a separate battery for the RX and flight controls. Also I am installing a Model Sounds Shockwave sound board and two exciter speakers with the T-28 radial engine sound. It really sounds realistic. The sound board recommends a separate battery on the RX that powers the low voltage side of the sound board. The amplifier and speakers take power directly from the 6S LiPo battery.
I am thinking about using the ESC BEC to run the electric retracts only. I think I could run the white signal wire from all the retracts to the RX retract channel and then run the retract red and black power wires to the BEC power output. Would this work correctly?
Also if the gears jam and overheat the BEC and cause it to trip the thermal protect shut down the only effect should be no gear operation. Flight controls should not be affected. My question is what happens to the ESC and motor power when the BEC shuts down. Does anybody know?
Thanks
Gary
I will use a separate battery for the RX and flight controls. Also I am installing a Model Sounds Shockwave sound board and two exciter speakers with the T-28 radial engine sound. It really sounds realistic. The sound board recommends a separate battery on the RX that powers the low voltage side of the sound board. The amplifier and speakers take power directly from the 6S LiPo battery.
I am thinking about using the ESC BEC to run the electric retracts only. I think I could run the white signal wire from all the retracts to the RX retract channel and then run the retract red and black power wires to the BEC power output. Would this work correctly?
Also if the gears jam and overheat the BEC and cause it to trip the thermal protect shut down the only effect should be no gear operation. Flight controls should not be affected. My question is what happens to the ESC and motor power when the BEC shuts down. Does anybody know?
Thanks
Gary
12-02-2015, 12:48 PM
#97
My Feedback: (9)
next attempt is going to be two flight systems one for the plane controls and one for the retracts. I have drawers full of those 6 buck orange rx's perfect for this.
Joe
12-02-2015, 04:50 PM
#98
My Feedback: (20)
All repairs and upgrades completed today. Found some orange red touch up paint from left from another project that nearly matches the orange on the T-28. Used my wife's flat black craft paint to touch up black. From 5' away it still almost looks like new again.
Paladin, I used a servo Y harness and another servo plug to make a wire harness that will use just BEC power for the retracts system. I clipped the red wire from the BEC to the RX so the RX does not see BEC power. I clipped the white signal wire from the BEC to the retracts so the retracts do not see throttle signal. I replaced the BEC white with another white wire from the RX retract channel to the retracts so the retracts get RX signal but not RX power. I used a separate battery to power the RX. Plugged it all in and it works great on the bench so far. I hope if the retracts jam and shut down the BEC the flight controls will not fail again.
Also got the Model Sounds Shockwave sound system from Dymond Modelsport USA installed and it is loud on the bench. It sounds great. Should be great outside.
All is left to do is reinstall a new steering servo and prop. They are in shipping now. I will not get them installed till next week due to weekend travel plans. Still need to figure out how to put the steering servo on another channel and make it inactive when gear is up. I am a Futaba 18MZ guy for jets but am using a Graupner MZ-24 with telemetry on my electrics. Still have not figured it out yet.
Paladin, I used a servo Y harness and another servo plug to make a wire harness that will use just BEC power for the retracts system. I clipped the red wire from the BEC to the RX so the RX does not see BEC power. I clipped the white signal wire from the BEC to the retracts so the retracts do not see throttle signal. I replaced the BEC white with another white wire from the RX retract channel to the retracts so the retracts get RX signal but not RX power. I used a separate battery to power the RX. Plugged it all in and it works great on the bench so far. I hope if the retracts jam and shut down the BEC the flight controls will not fail again.
Also got the Model Sounds Shockwave sound system from Dymond Modelsport USA installed and it is loud on the bench. It sounds great. Should be great outside.
All is left to do is reinstall a new steering servo and prop. They are in shipping now. I will not get them installed till next week due to weekend travel plans. Still need to figure out how to put the steering servo on another channel and make it inactive when gear is up. I am a Futaba 18MZ guy for jets but am using a Graupner MZ-24 with telemetry on my electrics. Still have not figured it out yet.