Syd Atkinson

My winter project is to make retracts for my Top Flite P47. The basic Robarts design looks like a good place to start ,my question is .What are the pros and cons of air down versus spring down. Thanks Syd .A

pitsspecial

Hi Syd,

Mite be worth thinking about what happens when you store it? if you have your wings on a rack then with 'spring air' design you would have to find a way to keep them in so they dont get in the way...... but!! if you store it with the wing on then to have the gear down and 'locked' is something to think about, ive had both types, both work well, with spring air if the air leaks at least they come down so you can land with the gear down, air up/down you dont have a choice, if they havent locked in there retracted postion you could end up with one gear up and one down!!! EEKK!!!

Happy flying,

Di n Dave....

BarryReade

My Feedback: (1)

LADO Technology

Maximiliano Galvez

I made my retracts for my giant scle top flite p47, I tke 2 years studing and making the pices. Each retract has more than 70 pices, but works and seems very nice. Works wit a 50 oz micro servo modified.
I you want to do it I think is a very nice project. All comerial retracts are not scalee. Either the position of the retracts that sugest top flite. I made too modifications to fit it as more scale.
Hope you enjoy it and any help you need please tell me

[youtube]http://www.youtube.com/watch?v=jAsHa3a4msw[/youtube]
[youtube]http://www.youtube.com/watch?v=V78l877ry3E[/youtube]

LDM

My Feedback: (15)

very interesting , did you ever think of getting them massed produced ? YOu could make some nice money just look at the Lado post

Maximiliano Galvez

some good friends as you tell me the same. I dont know if it could be a good market or bad inversion

ZERO-322

My Feedback: (2)

Again as stated above check out lado retracts the guy is making so much money he can't keep up with demand, people are yelling at him not because his products are not a quality inovative product, but because there is such a huge market with no competition he can't make them fast enough, You don't have to worry if you could keep up you would make allot of money !

paladin

My Feedback: (9)

Mechanical – can not lift the wt of air so 10oz tires are out. Retracting needs to be done in 1G flight.

Air/Spring – gives the wt lifting capability of air so you can lift a heavy scale wheel. It gives you the peace of mind that the gear will come down. But you pay for that by having to deal with the gear down during storage. I deal with this by blocking the gear up into the wing for storage. After a few years I had to re-oil the cylinders because the retract would not come down reliably. I have three pair of these two in the box and one on a plane with thousands of flights.

Air/Air – great lifting capability. Will allow for scale retract speed down AND UP. While these retracts will fail if air is lost I’ve had very good luck with them just ground checking. I have 12 of these all in airplanes, my oldest set is air/air with thousands of flights on them.

I’ve had the same number of failures between air/air, air/spring, and mech its just that the failure point changes. So if I where you get what you want and learn the failure points for that one and enjoy!

Joe

rc34074

My Feedback: (5)

The air up/spring down design is the way to go, in my opinion. Spring Air has made this design for a long time (20 years or more from what I can tell). I have used them for 10 years and they have an excellent strong design. They have never failed to extend and lock. They don't need to be lubricated or messed with unless you damage them on landing - I have tested this more than once . Spring Air had a patent on this design so they were the only ones making this design until a few years ago when the patent ran out. Then Robart came out with air up/spring down retracts. Robart has two series of this design now, a 500 series and a 700 series. I haven't used the Robart design much yet.

The point about storage is the only drawback but its never been an issue to me.

I use the Robart fill valve and a 12 volt electric compressor to fill the tank. The standard air valve used on some air compressors will work on the Robart fill valve without using the screw in connection. Lately I have been using the connectors from Wal-Mart foot powered bike tire pumps when mine need to be replaced (about every 3-4 years). I cut the hose off the foot pump and connect it to the compressor. Works great.

Ed

larry@coyotenet

My Feedback: (21)

Spring down gear have one big advantage, they come down if pressure is lost. Two problems, you can't regulate the speed of the down action if you want more scale like action and sometimes you need to land wheels up, for instance when the engine dies and you can't make it back to the runway, in that case you better hope you have air to pull the gear up. I know this is a worst case instance but I have seen it happen numerous times, Murphy always wins!

Larry

rc34074

My Feedback: (5)

Hmmmmm- seems to me that the need to pull up the gear could occur regardless of the type retracts you have. If you have air retracts you need air to retract either style. If you have electric you need battery power to retract them.

Right?

Ed

ZERO-322

My Feedback: (2)

Exactly a good 6v battery with high Mah and your all set to go none of the headaches that come with air and mechanical retracts once you've tried electric retracts you'll never put in anything else, best thing to come out since slice bread ! LOL

rc34074

My Feedback: (5)

So how is an electric retract better - why would it be sure to be better than air retracts? Electric could have problems too. Its just another way to operate the retracts but there is no reason why electric powered retracts are certain to be better. Certainly its possible that they could be made better but there's no certainty that they would be better. What happens if the battery fails? what if the electric motor fails or the mechanical parts jam or fail?

Any design can have problems. Maybe one manufacturer has a better design so their retracts are more reliable but there is not certain they will not fail.

But I can see that you really like the electric retracts you have, and that is good. Maybe they have the design that will take over the market.

But I like the air retracts that I have used for many years. To me they are easy to install, strong, and reliable. They take very little maintenance. So for now I will stick with them..

Ed

prop wash

I like air.I have also been flying with them for years and they have not failed me.I have H9 e retracts that are a real head ache to get tuned just right so they don't jam and burn out. I've had to make many gear up landings because of the electrics and they are not cheap.The servos[JR 791] are very strong but when they burn out they cost a lot. My robarts work all the time everytime.But everyone to their own tune.Tom

ZERO-322

My Feedback: (2)

the what if factor can and does exist with anything and everything with this hobby, what makes an electric retract better ? well for one there are no airlines to set up or maintain you don't need to constantly monitor air pressure and carry an air tank with you to the field all of the inherent problems with air and mechanical retracts don't exist with electric, what if the battery dies ? Your retracts not extending on final would be the last of your worries(you could always belly land) battery going out would probably result in a crash before you even realized you can't use them

phatbob02

My Feedback: (126)

With the electronic LADO's:
If the battery fails, you've got more to worry about than your retracts. They operate off the receiver battery.
No can of air, hoses ,or fittings to leak.
No air pump required.
No servo.
4 mounting screws and a servo plug.
More of a realistic operating speed with a stagger option.
Won't collapse if for some "never happened" reason they're not fully extended.
No maintenance at all.
Built like tanks.

I've ordered my 5th set.
Air is a thing of the past!

ZERO-322

My Feedback: (2)

lado electric retracts do not operate off a Servo but are a self contained unit that plugs straight into the receiver off a y harness, there are two failure points to these 1 the RX battery can malfunction, 2 the wire connecting the retracts to the strut used can bend if not heat treated, nothing is bullet proof but I think this is a wonderful option worth a second look

phatbob02

My Feedback: (126)

Like I said, If the receiver battery goes, you've got bigger problems than your landing gear.
If your bending strut wires, practice landing. A soft wire between the strut and retract is a failsafe from ripping your retract out of your wing.

Maximiliano Galvez

I dont like air retracts. There are not soft, and not scale. You can add a regulator but is not reliable because each time you gear up and gear down the retarc you losse preasure.
You have more than 10 tubbing conections that is more than a Y hanes where you can get 2 point of failure.
In the mine I design i put a 500mah batery pack and I cxan gear up and down the retrac more than 40 times
Maximiliano