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Old Dec 27, 2005, 08:04 PM
Build'em and Crash'em
Ken Lapointe's Avatar
Narragansett, RI
Joined Oct 2000
3,265 Posts
Discussion
Easy gear door mechanism for Retracts ?

I was trying to put a door on my retracts for my JHH F-86. The only one I really need is on the nose gear. Anyone have an easy way to make the door open and close without hitting the gear strut everytime?

Is a door door sequencer for a seperate servo the only option ? Is there a good cheap unit?

Just trying to keep the weight and space down.

Thanks,

- Ken
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Old Dec 28, 2005, 05:02 AM
Claus at Area 52
clausxpf's Avatar
copenhagen Denmark
Joined May 2002
2,538 Posts
You just need a "bellcrank" that only works on the wheels last 5 mm of travel, and that is for the full travel of the door. I little spring holds the door in open possision.
I think the wheel will be the best to put movement to the bell crank.
I have seen it done in the scale forum ... but long time ago.
but I liked the simplicity of the idea.
Claus
if needed I can do a simple drawing on the system later today
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Old Dec 28, 2005, 09:00 AM
Registered User
Joined Apr 2005
229 Posts
You could let the wheel open and close the door by giving the door a 90 or less degree bend on top, and adding a spring to keep it open.

Heres a simple front view drawing, something I experimented with once.
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Old Dec 28, 2005, 09:49 AM
One eyed Corsair
GGRN's Avatar
PARIS
Joined Jul 2005
2,319 Posts
Here is pic of my f8 nose gear hatch "mechanism" (better than long speaking), I hope it'll help you...
http//www.rcgroups.com/forums/attachment.php?attachmentid=682355
Greetings from Paris
Philippe
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Old Dec 28, 2005, 02:06 PM
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Gordon's Avatar
Joined Aug 2000
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Here are a couple of ideas, both of which I've used.

The diagram shows the system I used on a big GDF Hawk, using a sprung leg and mechanical retract mechanism, though a pneumatically operated system would work too. A side-hinged nose-gear door could use the "U" spring with one end fixed on the opposite side to the hinge.

The photos show the idea dreamed up by Ralf Dvorak for the El Bandito. The front door is operated by the piece of tube and sponge glued on the inside of the door and sliding on the wire nose-leg. The side door is operated by a sub-mini servo, and Orbit gear door sequencer from http://www.orbitronic.de/

Gordon
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Old Dec 28, 2005, 02:46 PM
smug in granny panties
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NorCal Silicon Valley
Joined Aug 2002
11,779 Posts
I've also done the trick where you put the gear up and CA a string from the non hinge side of the door, over the gear, and to the fuse right next to the hinges. This way if its set tight when the gear is up then it lets the gear flop open as soon as the gear goes down. Then as the gear goes up it only ppulls the door shut as the gear goes full up. Combined with a arm on the door attached to a rubberband you can spring load the door open.

Barry
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Old Dec 28, 2005, 04:35 PM
One eyed Corsair
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PARIS
Joined Jul 2005
2,319 Posts
I think i missed something with link. here are pics of my F8 gear hatch. Greetings from Paris
Philippe
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Old Dec 28, 2005, 04:59 PM
Build'em and Crash'em
Ken Lapointe's Avatar
Narragansett, RI
Joined Oct 2000
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Thanks for all the great ideas guys. I'll have to experement and work something out

Thanks again for the help

- Ken
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Old Dec 28, 2005, 05:45 PM
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ATA Flyer's Avatar
United States, CA, Temecula
Joined Nov 2001
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Please post what ever you come up, it could be a help.
Thanks
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Old Dec 29, 2005, 01:11 PM
Build'em and Crash'em
Ken Lapointe's Avatar
Narragansett, RI
Joined Oct 2000
3,265 Posts
Well all your ideas paid off guys

I set up a rubber band tied to the offset hinge to hold the door open. I then placed a small piece of wire bent at an angle on the door. The wire has a hook shape on the end to catch the gear in the up position. As the gear comes up it pushes against the wire to close the door and then the hook holds the door closed when the gear is up. Gear comes down , moves away from the wire and the rubber band holds the door open.

I wish I could say that it was that easy to get working and get everything right. It took me a few mods and changes to get to this point but it seems to work.

Again thanks for all the help guys

- Ken
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Old Dec 29, 2005, 01:37 PM
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Nice!
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