News:



  • June 06, 2024, 03:40:30 PM

Login with username, password and session length

« previous next »
Pages: [1]   Go Down

Author Topic: Timer Actuated Retracts  (Read 618 times)

Offline Ken Culbertson

  • 24 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 6187
Timer Actuated Retracts
« on: November 22, 2019, 11:28:32 AM »
Some postings on another thread have re-sparked my interest in learning to use Retracts.  If you search our base most of what you find is pretty old or servo/RC oriented.  I want to try the servoless type controlled by the timer like what Bob Hunt is using.  I have a Huben with the retract function and would like to know if anybody our there has tried the "cheaper" servoless retracts.  I plan on converting an ARF Nobler to something useful this winter and it will be a good place to learn if this is the way I want to go on my next build where I would use a higher quality such as the E-Flite.

My main goal in playing with this is to see if I can build an inward folding set of wheels with covers that will properly seat in the wing so that the airfoil is not affected.  I am pretty sure that it can be done I just need to find out if I can do it.  I have sketched it out and the geometry works with a very forward mount.  If anyone has already tried this I would appreciate any feedback.

Ken
Logged
AMA 15382
If it is not broke you are not trying hard enough.
USAF 1968-1974 TAC

Online Shorts,David

  • 21 supporter
  • Trade Count: (0)
  • Captain
  • *
  • Posts: 627
Re: Timer Actuated Retracts
« Reply #1 on: November 22, 2019, 12:35:40 PM »
I'm jumping to second that question.
Logged

Offline Tim Wescott

  • 2016 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 12829
Re: Timer Actuated Retracts
« Reply #2 on: November 22, 2019, 12:54:20 PM »
I haven't tried it, but if it works for RC, and if you make sure it's heavy-duty enough (using gear for an equal-weight RC plane is probably good enough), and if you compensate for the fact that you're otherwise compromising the structural integrity of your wing in the vicinity of the LG well (meaning, if you cut into the LE sheeting put a plywood surround around it), then I don't see why it won't work.

I'm already contemplating a TUT variation for someone that'll implement a Renicle-like motor speed sensor on top of a Howard-Rush style "hijack the Igor timer".  Basically it'll be set up to manage the gear without interfering with the timer, but if the motor craps out in flight the landing gear will go down immediately, hopefully in time for you to land on the wheels instead of the prop.

Of course, if your motor only ever cuts out when the timer tells it to, and never because you have electrical problems, you can just use the Hubin timer.
Logged
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Ken Culbertson

  • 24 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 6187
Re: Timer Actuated Retracts
« Reply #3 on: November 22, 2019, 02:34:25 PM »
Quote from: Tim Wescott on November 22, 2019, 12:54:20 PM
I haven't tried it, but if it works for RC, and if you make sure it's heavy-duty enough (using gear for an equal-weight RC plane is probably good enough), and if you compensate for the fact that you're otherwise compromising the structural integrity of your wing in the vicinity of the LG well (meaning, if you cut into the LE sheeting put a plywood surround around it), then I don't see why it won't work.

I'm already contemplating a TUT variation for someone that'll implement a Renicle-like motor speed sensor on top of a Howard-Rush style "hijack the Igor timer".  Basically it'll be set up to manage the gear without interfering with the timer, but if the motor craps out in flight the landing gear will go down immediately, hopefully in time for you to land on the wheels instead of the prop.

Of course, if your motor only ever cuts out when the timer tells it to, and never because you have electrical problems, you can just use the Hubin timer.
This is just proof of concept to make all the stupid mistakes and re-do's on something that is never intended for competition.  I found a set intended for RC up to 100oz on E-Bay for about $12.  Probably crap but if they work for even a little while I can work out the kinks.  We land a whole lot softer that RC dudes and I don't want to even think about flying CL at 100oz!

I would be interested in how anyone planning something like this is going to get the 2nd door to close (the little one that covers the bottom half of the wheel). I have some ideas that would make make "Gadget Man" proud but if someone has already solved the problem then I will just steal their idea.

Ken
Logged
AMA 15382
If it is not broke you are not trying hard enough.
USAF 1968-1974 TAC

Offline Howard Rush

  • 22 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 7818
Re: Timer Actuated Retracts
« Reply #4 on: November 22, 2019, 02:38:17 PM »
The TUT would have the added benefit of extending the gear after a crash, which causes me to LOL (as they say on the Internet) just thinking about.
Logged
The Jive Combat Team
Making combat and stunt great again

Offline Ken Culbertson

  • 24 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 6187
Re: Timer Actuated Retracts
« Reply #5 on: November 22, 2019, 03:10:09 PM »
Quote from: Howard Rush on November 22, 2019, 02:38:17 PM
The TUT would have the added benefit of extending the gear after a crash, which causes me to LOL (as they say on the Internet) just thinking about.
I was thinking about mounting them center wing so I could extend them either way if the motor quit but I couldn't find any that would do that - darn.  I have to lol too, reminds me of a roadrunner cartoon.

Ken
Logged
AMA 15382
If it is not broke you are not trying hard enough.
USAF 1968-1974 TAC

Offline Tim Wescott

  • 2016 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 12829
Re: Timer Actuated Retracts
« Reply #6 on: November 22, 2019, 03:18:25 PM »
Quote from: Ken Culbertson on November 22, 2019, 03:10:09 PM
I was thinking about mounting them center wing so I could extend them either way if the motor quit but I couldn't find any that would do that - darn.  I have to lol too, reminds me of a roadrunner cartoon.

Ken

Peter German posted a picture of a plane with fuse-mounted retracts.  They extended and retracted like a Cessna 182RG; that should work.
Logged
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Tim Wescott

  • 2016 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 12829
Re: Timer Actuated Retracts
« Reply #7 on: November 22, 2019, 03:22:09 PM »
Quote from: Ken Culbertson on November 22, 2019, 02:34:25 PM
This is just proof of concept to make all the stupid mistakes and re-do's on something that is never intended for competition.  I found a set intended for RC up to 100oz on E-Bay for about $12.  Probably crap but if they work for even a little while I can work out the kinks.  We land a whole lot softer that RC dudes and I don't want to even think about flying CL at 100oz!

I would be interested in how anyone planning something like this is going to get the 2nd door to close (the little one that covers the bottom half of the wheel). I have some ideas that would make make "Gadget Man" proud but if someone has already solved the problem then I will just steal their idea.

Ken

You could sequence it with another servo!

Just leaving the door off would probably work.  Compared to the advantage of the gear, leaving that little hole wouldn't mean that much, IMHO.

Or ask on RC groups -- I bet it's a many-times-solved problem in RC-land.
Logged
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Ken Culbertson

  • 24 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 6187
Re: Timer Actuated Retracts
« Reply #8 on: November 22, 2019, 04:10:03 PM »
Quote from: Tim Wescott on November 22, 2019, 03:22:09 PM
I bet it's a many-times-solved problem in RC-land.
With Servos!  Why use servoless retracts just to add a servo & the electronics to drive that dinky door.  You are probably right about the wheel well not being much of an issue.  I was hoping to get it to work so that I could make the main covers as small as possible so it could fly off of grass.  Can't go swapping out gear with retracts.  With all that crap moving there has to be a way to rig a linkage to keep them open till the wheels get in.  Small light force magnets may work to hold them in both open and closed position and let the wheels push them into position. Not as strong as the ones Tom sells.  I's never get the gear down!

Ken 
Logged
AMA 15382
If it is not broke you are not trying hard enough.
USAF 1968-1974 TAC

Offline Tim Wescott

  • 2016 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 12829
Re: Timer Actuated Retracts
« Reply #9 on: November 22, 2019, 06:16:11 PM »
Older designs would have been purely mechanical.  In 1978, a servo cost a lot and was heavy -- you didn't go wasting more than one of 'em for retracts.  I'm sure there's arrangements where the door is spring-loaded in the down position, and the incoming wheel pushes it closed with a lever.
Logged
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Tim Wescott

  • 2016 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 12829
Re: Timer Actuated Retracts
« Reply #10 on: November 22, 2019, 06:24:03 PM »
Logged
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Ken Culbertson

  • 24 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 6187
Re: Timer Actuated Retracts
« Reply #11 on: November 22, 2019, 06:43:48 PM »
Quote from: Tim Wescott on November 22, 2019, 06:24:03 PM
I repeat:

https://youtu.be/ZnToe7zOa8E?t=55
It would never pass the pull test.

The spring is the answer.  I had drawn up one with the spring holding it closed.  My problem was the timing in getting it open.  Holding it open is the answer - back to the doodle pad - Thanks

Ken
Logged
AMA 15382
If it is not broke you are not trying hard enough.
USAF 1968-1974 TAC

Offline Phil Krankowski

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 1031
Re: Timer Actuated Retracts
« Reply #12 on: November 22, 2019, 08:27:02 PM »
Logged

Offline Ken Culbertson

  • 24 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 6187
Re: Timer Actuated Retracts
« Reply #13 on: November 22, 2019, 08:52:48 PM »
Logged
AMA 15382
If it is not broke you are not trying hard enough.
USAF 1968-1974 TAC

Offline Tim Wescott

  • 2016 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 12829
Re: Timer Actuated Retracts
« Reply #14 on: November 22, 2019, 10:37:42 PM »
Quote from: Ken Culbertson on November 22, 2019, 08:52:48 PM
Still needs servos.  This has to be simple and mechanical except for the servoless retracts.

Ken

You are aware that there are some insanely light servos out there, and a door isn't going to load anything at all, yes?  (And a TUT can do the sequencing, to a limited extent).

Sometimes the lightest and outwardly simplest solution is the "most complicated".
Logged
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Advertise Here
Pages: [1]   Go Up
« previous next »
Tags:
 


Advertise Here