Here is one topic that I always get questions on and dont have any real good "Tips" to make the job any easier. Frankly, I hate hinging... Period. [:'(] So, if you have any helpful tips on hinging gear doors or cylinder installation, lets compile them here to help our fellow builders out....

One method.. if they are part of the fuselage .Hang the doors before cutting them out .Cut most of the door out leaving them attached in mid span , hinge, finish cutting them out .
Semper Fi
Joe

Also, what are the +/- of air operated gear doors as opposed to mini servo operated doors. With something like a jetronics sequencer doesn't it allow you to have nice slow (adjustable) opening gear doors and no worry of air loss, multiple air tanks in the model etc??

Mark

Mark try and put a restrictor in the up line to the pneumatic pistons
Semper Fi
Joe

Use gel CA for hinges!

Joe, have used the airline restrictors with some success but will be trying the servo route next time on my Airworld Hawk for easy install, reduction in air lines, easy endpoint adjustment, totally adjustable speed etc etc

Rgds,
Mark

Here's the answer: there ain't no secrets. Gear doors are voodoo. The geometry is incomprehensible and even if you eventually get it right it won't be the same when you put 100 psi on it. If you get it working with 100 psi then it won't work in flight due to air loads, airframe flexing etc. If you get it working in flight then it won't work the next time....just because their gear doors and gear doors are voodoo.

Speaking from experience,

Craig

Craig, I agree with you, I can't stand the darn things, Voodoo works for me. Or down here in TX we call it PFM.

Mark, what kind of servos do you have in mind for gear doors?? V..

Vincent,

Hmmm, need to do a bit of research but saw these and liked the look of them...

http://www.servocity.com/html/hs-85m...hty_micro.html

whilst I'd never put a Hitec servo in one of my jets I thought these would be fine for a gear door?

Rgds,
Mark

PS Just noticed that a certain World Jet Master used servo actuated gear doors on his Hawk

time for me to play it expert :P hahahaha


anyway gear doors r easy to me.......

1: you get the hinges on before you cut them our from the fuse!!

2: remember to LINE UP all of them so they wont fight against each other .....easy if you pass throu all of them a

a straight stif wire in there same holles before you glue them.....and remove it later....i leave it on as the forces from cilinder to each
hinge dont go throu the door but throu this wire....

3: even if you use the strongest and more expencive glue on the planet......just open holes to every one and secure them also with
small screws and nuts....i get mine from optick shops.... i mean the srews and nuts they have in our glasses we wear
....this will hold you door for ever with out worry for bad sorprises....


...............I HATE SOOOOO MUCH MY ENGL. WHEN I TRY TO HELP SOME ONE AND I CANT....

GRRRRRRRRRRRRRRRR


4: and dificult!!! silinder sizes and posisions...

i dont know how you call it in english this force but is the one that has to do with power and distance..

so it goes like that ... the less distance you have from the point you want to turn the more power you need to turn it.

so...i prefer to have a longer stroke silinder than the standart and work easyer to open the door than a shorter

to fight and work harder......the open point of the door i like it to make it from the end position of the silinder stroke...

the close point of the door i like it to be made by the rest of the fuse..so when my doord r up silinder is not all the way up but it hold them egenst the fuse....hey not alot! just 5mm before its end...

5: and lines now...spent extra some $ and cut them simetrical....i mean the same lenth so all doors act the same

.........if you havent get the step 4
let me know and ill try to sent some photos and draws for you tonight


take care

regards
georgy



baseball,fooball,basketball,tennis & golf require only one ball............jets takes two

Hi,
1. Make the assumption (if you land like me) that you are going to knock them, even in the workshop.
2. Glue in place with thick cyano after roughing up and cleaning the hinge and surface to be glued to. If at all possible put them in place before you cut the doors out.
3. Drift a little microballons or roket powder around the hinge and apply thin cyano, this means if you knock the door will come free but leave a pocket for it to fit back into with a little more thick cyano. Works or me (Often!!!)
Mike

Mike, that is an awesome idea! Thanks.

Make sure there are no easily offended people around to hear you when the ca gets your finger stuck or the hinges stuck.

1. Know that they will get torn off at some time. Don't get frustrated just don't install them if you don't want to fiddle with them.

2. Try to make them strong as you can. As George said above use screws to secure hinges to door and fuselage.

3. Bring extra hinges to the field

4. When using pneumatic cylinders I like to mount them to bulkheads or trays rather than to the side of the fuselage on small mounts. If you put them on the thinner parts of fiberglass fuselages, many times you will get bending of the fuse when pressure is applied to the cylinders.

5. Have a variety of hinge types around to get the job done. Offset hinges are made by BVM, Robart, Skymaster, Tams, UEI Sorry if I forgot any. Also Nelson Hobbies sells some nice piano type hinges.

6. I like to use Gel Ca it sits on the hinges till you kick it and it sticks well. Handibond has it, and I think zap too.

7. Play around with the hinges that your going to use. Especially the offset hinges, the spacing of the hinge to the hinge line, thickness of the door are all very critical for a good working door. Also a Dremel tool with carbide cutters like BVM's or Robarts are a good idea, you will probably have to cut clearances in doors or the fuselage at times to get the doors to work.

8. Try your best to make the cylinders and their lines easy to get at and well organized, it makes it so much easier to find leaks and replace parts. Dreamworks has some very nice clips that you can use to organize your air tube. I believe he also carries many different colors of tubing to use for different systems. I like to use dawn dishwashing liquid water and a small brush to hunt down leaks.

9. If you are using a turbine install with just the bell mouth on the tailpipe opening you should protect any exposed wires and airline with a thin aluminum, stainless steel, fiberglass, or carbon heat shield. Wire loom can also work well. It takes just a little too much gas on start and poof you can have melted airlines.

10. Go to jet meets and look at other peoples setups, you will see some great stuff out there, I know that I always learn new stuff.

I use .007 alu strips to line the edges so doors don't pull inside the fuse. Glue with goop. Cuts easier than Ployply with scissors and you can bend it to fit the door.

Also use those little rare-earth magnets on the front corner to keep the door shut tight.

I don't use the doorhinges!
I use the inner tube of a bicycle too make my one doorhinges!
This is very flexible and strong! Install it before you cut out the doors out of the fuse!
I perforate the inner tube at the place i want too glue it, so the glue ( epoxy) stitch good too fuse and rubber!
I saw this years ago on a german Lavi at a jet meeting. Since then i'am doing it also! And it works great!
And always use Strips of aluminium or wood too line up the edges!

Good luck!

I prefer air cylinders cos when you close the doors you need a little over ride closing action in most of the cases, and a servo can't stand this.-

I adjust the air cylinder travel by inserting a piece of plastic or brass tube cutted to an specific length into the cylinder shaft.....I'm sure this is no new

Also prefer to hold the hinges with screws instead of glue.

Call me crazy....bud I do enjoy playing with door's hinging [&:]

Doors are a pain, that is for sure.

Some very good hints so far. I can add:

1.) Get the hinge line as close to the upper skin as possible. The first photo is of the cutout for some Tam offset hinges (my favorite).

2.) Have the most clearance between the hingeline and the door opening, especially if the skin material is thick.

3.) Bevel the inner edge of the door (the one near the hinge), especially important if the skin is thick.

4.) Line up the hinges with a wire and if possible leave the wire in as the hinge and you have a removable door (a must if you ask me)

5.) Outer doors can use a little skin mount hinge made of brass tubing and music wire.