stevenmax50

My Feedback: (1)

I am building a TF 1/7 P-51. Iwant to put retracts on it and this will be my first retract installation. Ihave seen vids of models that had the inner doors operational. Ibet you would all agree that is the coolest. Iunderstand Iwould need a door sequencer and Ihave looked at several companies that supply these. What I am wondering is anyone can provide a link or directions to a thread or website or youtube vid that is basically a "how to". Iknow Ihave seen it in the not too distant past but Icannot seem to locate it anymore. Any help with info on inner door operation would be much appreciated.

BTW, Iam thinking Iwill not go to crazy on the scale main LDG on this one. Probably just install the Robart 605HD??? And if all goes well apply the new knowledge to building the 1/5th P-51 with oleos.

scale only 4 me

My Feedback: (158)

Way back when I had a top flite red box p-51b,, I built the clam shells and tried to engineer a complicated servo arrangement (basically a home made sequencer),, I ended up just putting the servo that operated the clam shells on an extra channel,, It was pretty easy to hit one switch, then the other, then the first again. No real need for a sequencer IMO

p.s.
I'd go with mechanical or electric retracts before I'd put pneumatics on this size plane

stevenmax50

My Feedback: (1)

LOL...I am hardly a good enough pilot to keep it in the air as it is.  Thinking about more than 1 swithch to get the gear up could be the end of that flight!!! 
I have seen several companies that advertise sequencers that will open the doors, lower the gear, close the doors...everything in order.  I am just hoping to get as much info as I can rather than rely on someone who is trying to sell me something.  I want to fully understand what I am asking for before I buy. 

MinnFlyer

My Feedback: (4)

Steve, if this is your first set of retracts, I'd say skip the doors for now. Retracts a definitely cool, but they are a pain in the butt. Get used to dealing with retracts for now and then decide later if you want to mess with doors too!

PS I prefer mechanicals too

stevenmax50

My Feedback: (1)

That definatly has be a thought.  Truth is in the back of my mind I figure thats the way I would probably go anyway.  But I think its time to start gathering all the info for the next attempt. That way while I am building this one I can make comparisons.  Just trying to expand my experiance and knowledge before I take the leap.  I just wish I had saved that vid I saw awhile back to favorites.  It showed door fabrication, hinging.  servo and sequencer operation.  All with the gear installed as well. I have had countless full scale Boeings up on jacks in the hanger and ran the gear for ops cks.  At some point my models will have to emulate that. I agree I may be biting off more than I can chew for a first time retract install.  I promise I will KISS and report progress as I go.  Thanks MinnFlyer, for keeping my head outa the clouds. 
Still looking for a vid on the door operation tho....

scale only 4 me

My Feedback: (158)

Well if you do choose to go with pneumatics get a UP2 Valve, that does the inner door sequencing for air systems
http://www.rcscaleproducts.com/retract_acc.htm

I've never used a electronic sequencer, but they're out there

buchtes

My Feedback: (7)

here are my retracts , :http://www.youtube.com/watch?v=gaTF1520QmM

scale only 4 me

My Feedback: (158)

buchtes
I hate to tell you this, but on the p-51 sequence the inner door close after the mains come down,,, that's what the UP-2 Valve does for ya

stevenmax50

My Feedback: (1)

Exactly Scale Only....the inner door must close after gear extension.  I assume to UP-2 valve is a total pneumatic system? 
I am gonna send RC Scale products an email requestion info on their products.  Thanks Scale.

mucksmear

Steve, if you go with mechanicals, it's quite easy.

Here's a picture because it's a bear to describe in words (but I'll try anyways). The diagram shows the servo and pushrods for the Retracted condition. Rotating the servo wheel CCW as per the red arrow brings us to the Extended condition. You can see that with 180 degrees of servo operation, the pushrods pair for the retracts as well as the pair for the inner gear doors essentially swap sides on the servo wheel. The difference is the inner gear door pushrods are located 90 degrees to the line of travel (12 and 6 O-clock positions), therefore they have a zero net change in position. In other words, both the 12 and 6 O-clock positions result in a closed inner gear door condition. The inner gear doors will be fully open when their pushrods are at the 3 and 9 O-clock positions, at which time the retracts will the half-way through their sequence.

That said, MinnFlyer has the right idea. I skipped doors on my Funscale Mustangs which were my 1st retracts. I did do this method of retracts later when I built my Duellist.

buchtes

My Feedback: (7)

This Issue has been resolved and the Gear and the Doors cycle now incorrect order and speed.
Buchtes

Zor

???Trying to interpret your posting.

It has been resolved ___BUT

the Doors cycle now incorrect order and speed. ???

Sorry I do not get what you are saying. . . . . It is resolved but is "incorrect" ?

Zor

Zor

Interpreting the sketch posted by mucksmear in post #10.

At the beginning of the servo rotation the doors linkage have fast motion opening the doors and the gear extension has minimum motion but increasong as the servo rotation contimues.

At the 90 degrees of servo rotation the doors are fully down and the gears are half way down

During the second 90 degrees of servo rotation the gears keep going down to the fully extended (down) postion while the doors return to their closed position.

Of course the linkages for the doors are at a different level than the ones for the gears to clear each other during the 180 rotation.

Very ingenuous.

Thanks for the posting.

Zor

buchtes

My Feedback: (7)

Zor: it should say in correct order...........................lol

Zor

It cannot be in the wrong order (sequence) since the linkages are fixed to the servo rotating disk and their movement is mechanically tied.

The trick is in the 90 degrees points of attachment.

Zor

Edited by Zor to change "in he wrong" to " in the wrong"

scale only 4 me

My Feedback: (158)

Are you using the up2 valve? can't tell via the video

Be great to see what it looks like now that it's corrected

buchtes

My Feedback: (7)

yes, I got the UP-2 and it works great. Will post another video later in the build, I'm at a stand still at this time . Buchtes