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Electric retracts?
A non-jet buddy accompanied me to a jet rally recently and made the observation that he was surprised that with all of the money modelers spend on jets that the landing gear retract systems are still so unreliable and require filling for each flight. Our discussion touched on the idea of hydraulics, but I informed him that one companies attempt at this was unsuccessful.
We thought about the fact that one of the biggest changes in the hobby recently has been LiPo’s supplying huge power in a lightweight package. Isn’t it time for manufacturers to start making electrically operated gear. Simply replace the air cylinder with a motor/wormgear assembly. You would need sensors to determine end travel and an ecu to control the units. I imagine that a 4200mah (7 oz) could power the system all day. With the right gearing you’d have tons of torque and the scale guys would get their realistic retract speed. How about small self contained units for doors and some sort of solenoid for brakes, running off the same ecu with multiple connections to the Rx? |
RE: Electric retracts?
Years ago electric retracts were common. Hal Debolts was one of the earliest designs. Later Ralph Andrae ( orig Wing Mfg )designed and built electric retracts. I still have some and they are not by any stretch of the imagination foolproof. Kraft radios also built some electric retracts that were bulky and rather touchy to operate. They had a seperate box for control that plugged into the Kraft rcvr.
Just my opinion but I believe the air operated ones are still the best . |
RE: Electric retracts?
Joe,
Likes Lines used to do electric as well years ago. Last week at Castle, there was a company there that had developed new electric technology for retracts. they where very nice setup. you send him your gear, and he retrofits his stuff into them. They where worm gear driven, and run off of their own power pac. very light and robust. he can make them do anything. slow up/down, fast up/down. I will look for my info on them and post them here. They are located in the LA basin area if I remember correctly. one of the coolest things about them, they operate like Spring Air units. If you loose battery power in flight, the gear come down automaticaly. that way you dont have to worry about the gear not working for you. BTW, thanks for the show up here yesterday. You did good and crowd loved it. Todd |
RE: Electric retracts?
I saw those retracts up at Castle and plan on getting a set for the Dragonfly. I'll let you know in a few weeks how they are.
Sung |
RE: Electric retracts?
Hey Hal, I understand your reluctance to revisit a system that proved to be less than optimal, but we've come a long way in electronics since the days of Kraft radios!
Thanks Todd! I look forward to checking out that system. It's pretty cool that they can retrofit existing retract units! It sounds like you're saying they have a low voltage failsafe...if the ecu detects the retract battery voltage dropping below a certain voltage it will drop the gear. That's smart, kinda like the unit Tam has for the pneumatics (that I didn't know about until yesterday.). |
RE: Electric retracts?
yes you are correct Joe. low volage and they drop. pretty nice fail safe. one of my
Admins at RCSB will be doing a review on them shortly. Hopefully Sung remembers the name of the company, as I cant find my paperwork on them. I will hopefully find when I get back from the Willow. |
RE: Electric retracts?
i also am instrested in hearing about the retrofits. i would like to see the web site, or a # to contact to get some info about these. i agree, its time to see some more reliable retracts. with todays technology and all the high powered batts. and micro motors i think it will only be time to see these changes.
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RE: Electric retracts?
Thats funny, I posted the info for Lado-Tech earlier and its no where to be seen. Well here it is again.
www.lado-tech.com is the website and you can email them at "[email protected]". I hope this helps Sung |
RE: Electric retracts?
Hi Joe, I had a set of the Geizandanners (Kraft) long ago . They were a bit bulkey for 60 size planes-not a problem now. The main problem was that they were not fused or clutched and if they jam before the end points this would lead to the all important smoke being let out of the components or worse the power lines melting with the possibility of conflagaration. Solve that problem and it should be a good deal. Scott
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RE: Electric retracts?
ORIGINAL: Rojeck Thats funny, I posted the info for Lado-Tech earlier and its no where to be seen. Well here it is again. www.lado-tech.com is the website and you can email them at "[email protected]". I hope this helps Sung thanks Sung! thats the info I was looking for |
RE: Electric retracts?
Hi
I've been working on electric retracts for quite some time now. They are in no means "easy to to", especially the wiring is very tochy and also complicated, as a simple "cutoff" will result in jamming. You need to electronically brake the motor the instant it hits the cutoff switch....not easy from the electronics-side. I now have the prototype rig up and running, and will soon be building the prototype version. The "ECU" will be about the same size as the JetCat/ProJet/Orbit turbine ECUS, and tests and calculations show that the cylinders will be "pushing" between 30kg and 100kg (66-220lbs). Gear cycle time will be around 2.5 seconds, with the speed being adjustable for each leg. The complicity and manufacturing expenses involved will probably make the pneumatic setups financially much more attractive than the electric types, those will probably only show up every now and then....my guess. Best regards Hank |
RE: Electric retracts?
I too had a set of Giezendanners in an old Bootlegger I had bought from Steve Stricker. They were OK and I never had any big issues with them (never had a hang-up problem). Only negative was that sometimes they glitched the radio while they were operating (pre-PCM days). Never huge glitches, just a minor few bumps. This could probably be cured easily with capacitors.
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RE: Electric retracts?
ORIGINAL: Miniflyer Hi I've been working on electric retracts for quite some time now. They are in no means "easy to to", especially the wiring is very tochy and also complicated, as a simple "cutoff" will result in jamming. You need to electronically brake the motor the instant it hits the cutoff switch....not easy from the electronics-side. I now have the prototype rig up and running, and will soon be building the prototype version. The "ECU" will be about the same size as the JetCat/ProJet/Orbit turbine ECUS, and tests and calculations show that the cylinders will be "pushing" between 30kg and 100kg (66-220lbs). Gear cycle time will be around 2.5 seconds, with the speed being adjustable for each leg. Gordon |
RE: Electric retracts?
what there weight will be?
also whats there cost?? ..............i like it simple. so i stay with air silinders...refeling after flyght its not a reason for me to leave air powered |
RE: Electric retracts?
Gordon, delGato
Yes, it will include a door sequencer. It is under development for a large (120") F-4 E/F Phantom (and partially an Avonds F-15), on which part of the gear doors remain open and others close. So both functions will be supported. It will, however, not be controlled with a time delay as most sequencers do, but it will work with a position sensor. As soon as the locked-position of the gear cylinder is reached (either up or down), the doors will cycle. That way the door will not run into the gear in case it cycles slower on an occasion (for whatever reason). The gear itself will be actuated by a cylinder just like the real thing. Weight of the running prototype is around 150grams, about 5 oz....weight is depending on maximum travel and required power, but with the 150 there should be plenty of power for most uses, including airbrake actuation. Radio glitches have not been noticed.....but we will do extensive range testing before sending one up. Once finished it will be a foolproof "plug and play" unit, but there is still some development to be done. We have not considered selling it commercially, but might consider getting something like that on the way if there is enough demand... Best regards Hank PS DelGato: refilling is not the main reason for me to go away from pneumatics...the main reason is reliability. An electric motor will turn when power is provided. Air can always spring a leak, and i've already had a few belly landings because of pressure loss, or a SpringAir not locking down properly (usually nosegear collapse)....electric is worry-free when charged, and you can always add an "emergency extension" via ECU power.... |
RE: Electric retracts?
Gordon,
the electric gear I am talking about (LADO) also have the capability to work with gear doors as well. open/shut, stay open, open gear down, doors close etc. they can make it do anything that is needed as well as timing. todd ORIGINAL: Gordon Mc ORIGINAL: Miniflyer Hi I've been working on electric retracts for quite some time now. They are in no means "easy to to", especially the wiring is very tochy and also complicated, as a simple "cutoff" will result in jamming. You need to electronically brake the motor the instant it hits the cutoff switch....not easy from the electronics-side. I now have the prototype rig up and running, and will soon be building the prototype version. The "ECU" will be about the same size as the JetCat/ProJet/Orbit turbine ECUS, and tests and calculations show that the cylinders will be "pushing" between 30kg and 100kg (66-220lbs). Gear cycle time will be around 2.5 seconds, with the speed being adjustable for each leg. Gordon |
RE: Electric retracts?
ORIGINAL: Miniflyer Gordon, delGato Yes, it will include a door sequencer. It is under development for a large (120") F-4 E/F Phantom (and partially an Avonds F-15), on which part of the gear doors remain open and others close. So both functions will be supported. It will, however, not be controlled with a time delay as most sequencers do, but it will work with a position sensor. As soon as the locked-position of the gear cylinder is reached (either up or down), the doors will cycle. That way the door will not run into the gear in case it cycles slower on an occasion (for whatever reason). The gear itself will be actuated by a cylinder just like the real thing. Weight of the running prototype is around 150grams, about 5 oz....weight is depending on maximum travel and required power, but with the 150 there should be plenty of power for most uses, including airbrake actuation. Radio glitches have not been noticed.....but we will do extensive range testing before sending one up. Once finished it will be a foolproof "plug and play" unit, but there is still some development to be done. We have not considered selling it commercially, but might consider getting something like that on the way if there is enough demand... Best regards Hank PS DelGato: refilling is not the main reason for me to go away from pneumatics...the main reason is reliability. An electric motor will turn when power is provided. Air can always spring a leak, and i've already had a few belly landings because of pressure loss, or a SpringAir not locking down properly (usually nosegear collapse)....electric is worry-free when charged, and you can always add an "emergency extension" via ECU power.... if u can make them so good im with you![sm=thumbup.gif] |
RE: Electric retracts?
ORIGINAL: GSR Hi Joe, I had a set of the Geizandanners (Kraft) long ago . They were a bit bulkey for 60 size planes-not a problem now. The main problem was that they were not fused or clutched and if they jam before the end points this would lead to the all important smoke being let out of the components or worse the power lines melting with the possibility of conflagaration. Solve that problem and it should be a good deal. Scott |
RE: Electric retracts?
Hello all,
This is Doug from Lado Technologies. I am surprised the word is getting around so quickly. Since our web site is still underdevelopment I thought I would put a few details up here about the electric retract actuator I have developed. Also I wanted to note that our design uses all solid state electrics and no micro switches. All the electronics is built right on to the actuator and still only weighs 2.6 oz. with 35lb. of push/pull force. We will also have a gear door sequencer available soon that takes advantage of some cool timing features built into our actuator. [img][/img] The Electric Retract Actuator is a replacement for the air ram in your air retracts. The actuator can fit in most 1/5 & 1/4 scale air retracts from Robart and other retract manufactures. Our electric retract actuator has all the electronics built right on the actuator. Connect the actuator directly to your receiver or through our Gear Sequencer. When connected to your receiver you use the end point adjustments in your computer radio to adjust the speed of the actuator. An encoder build right in the actuator regulates the speed of the actuator. Thus giving you precision control and a very scale looking and reliable retracts. The actuator has built in electronics that automatically stop the actuator when the landing gear is fully retracted. The electronics also prevents a continuous current draw in the case of a binding retract or malfunction. At any time you can switch direction even if a malfunction or bind has been detected. Also built right into the actuator is a low battery fail safe. This automatically extends the landing gear if the battery voltage drops below a safe point. SPECIFICATION MIN TYPICAL MAX UNITS Voltage 4.00 4.8 to 6.0 6.70 Volts Current Draw @ Stall - 1.20 - Amps Current Draw Idle - 0.05 - Amps Current Normal Retract 0.15 0.40 0.75 Amps Retract Speed * *5 - *15 Seconds Batter Fail Safe Threshold (4 Cell Pack) 4.40 4.60 4.80 Volts Batter Fail Safe Threshold (5 Cell Pack) 5.40 5.70 5.90 Volts Push Pull Force @6.0V Stalled 31.5 35 38.5 Pounds Weight Per Actuator - 2.6 - Ounces I would like to hear from you. If you have questions or comments you can contact me at: [email protected] or 530-589-9179. We have completed our first product run and taking orders, the web site should be up late this week. Thanks, Doug |
RE: Electric retracts?
Also you can see a picture at the new products posting.
http://www.rcuniverse.com/magazine/n...roduct_id=1216 Thanks, Doug |
RE: Electric retracts?
Doug,
Very impressive, good luck on your venture. Paul |
RE: Electric retracts?
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Gordon, I sent you a link to a video of the Lado electric retract actuators. I didn't know this thread was in progress but it fits right in. I have ordered my set and look forward to using Doug's great product!
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RE: Electric retracts?
Any Updates on Lado's system ?
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RE: Electric retracts?
What would be the simplest and best brake system to go into an "airless" airframe?
A syringe and servo type or? Lars |
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