N200LZ: Chapter 13

[JTest]

G'day TMann

 

The picture looks like you may have used a Large Space Bag. The vacuum section looks like one. Is that what you are using? If so how do you regulate / measure the internal vacuum pressure? Or do you? If not, is it important?

 

I know lots of questions, but the picture started me thinking. A very dangerous thing....usually. "MOM, lock the kids in the basement for their safety!"

 

Looks good. I hope to get some time this weekend on mine.

 

Jeff

[TMann]

The bags are actually a tube laid out flat a then put on a roll. You cut them to length then you seal the end with a 'C' clip. (a long 'C' channel that accepts a plastic rod. The bag material goes between the two.)

 

The pressure is regulated by a vacuum swith that shuts off the pump when the desired level is reached.

[JTest]

The bags are actually a tube laid out flat a then put on a roll. You cut them to length then you seal the end with a 'C' clip. (a long 'C' channel that accepts a plastic rod. The bag material goes between the two.)

 

The pressure is regulated by a vacuum swith that shuts off the pump when the desired level is reached.

G'day TMann

 

Thanks for the information...

 

"Mom, you can put the blankets back in the space bags and bring the kids out of the basement. I think it is safe again!"

 

Jeff

[TMann]

I did my hard point for the nose gear pivot a bit different from plans (Long-EZ plans that is.) I liked the beefed up version in the AreoCad plans so I blended the two.

 

I made the NG8 per plans but used the phenolic for the hardpoint and made the doubler per the AeroCad plans. This calls for a longer AN5 bolt for the NG6 as well as longer screws to attach the NG8.

[Neverquit]

The intersection points on the NG30s I radiused and raised the NG30 height by 2 inches. On the Cozy there's an old newsletter that Nat suggests adding an extra 2 layers of BID for strength for possible wheel shimmy. ...just some thoughts. Here's a couple crummy photos.

[Lynn Erickson]

The intersection points on the NG30s I radiused and raised the NG30 height by 2 inches. On the Cozy there's an old newsletter that Nat suggests adding an extra 2 layers of BID for strength for possible wheel shimmy. ...just some thoughts. Here's a couple crummy photos.

where you need the extra plys is on the sides at the front gear leg attach point. there is a lot of side to side flex in that area I would add a couple of plys that tie in the floor and bulkhead to the NG 30. I noticed a lot of flex and latter added 3 plys of heavy carbon bid. it helped a lot but there is still a little flex.

[TMann]

Well, I did learn something. When I hollowed out the nose section between FS28 & FS 0, It didn't leave enough structure to prevent warp during cure. I ended up with a slight twist in this piece after it was cured.

 

I entertained the Idea of either Heating the piece and then trying to jig it back into the proper position or maybe add fill to correct the shape.

 

After kicking it around, I figured it would take less time to just rebuild that segment. I ordered up some foam from Wicks ($40) and it arrived late Friday. By Saturday I had it cut, shaped and hardshelled. I'll try and sneak in a little time on Sunday and get the hatch cover layup done. That should put me on track to have the outside skinned by mid-week.

 

This time I won't remove the inner portion of the core until after a full cure of the outside skin. After measuring the bad piece, I fgured I can cut out the core in one shot with the hotwire and end up with pretty much the same usable space, It will also make it easier to get the level floor I need to mount the adjustable rudder pedals.

[TMann]

I'm working on the nose gear doors right now and found some interesting stuff.

 

Jack Morrison and Al Wick both made a wider nose strut cover which acts as a speed brake as well as a cover. Mine is going to be 5 inches wide. I used 4 plies of 716 CF Uni for the outside skin and have yet to install the foam backing and inside skin. It will be spring loaded to fornm a tight yet forgiving seal against the fuselage when closed. The CF provides a nice stiff door skin.

 

I also have been reviewing the Berkut drawings for the nose gear door mechanism. I've decided to go with that setup. I made a CF leaf spring out of 4 plies of CF 703 tapes 1.5 inches wide. It fits inside the nose wheel cover and in a relaxed state deflects downward about 3 inches. When the nose gear retracts it will push it up futher inside the well. The music wire (.118 ") is attached to both the spring and the doors. They have a relief spring shape (see pic) formed into them which provides a bit of forgiveness while at the same time, exerting plenty of pressure to hold the doors shut. I'll post some pics later when it's installed. The whole concept was a bit difficult for my little brain but after revisiting the plans several times it began to sink in. (I'm wondering if I could use this method for P-51 style doors on the mains.)

 

Anyway ........ this led to my search for the proper way to work music wire. The attached article outlines in detail the procedure for removing the temper (thus making the wire softer) to easily form the proper shape. You then need to restore the temper t a hard state (too brittle for our needs) and then back it off to a 'spring steel' state which is just what is needed.

 

Yeah ....... there may be a simpler way but this is how mine will be done.

BendingMusicWire.pdf

[Lynn Erickson]

I'm working on the nose gear doors right now and found some interesting stuff.

 

Jack Morrison and Al Wick both made a wider nose strut cover which acts as a speed brake as well as a cover. Mine is going to be 5 inches wide. I used 4 plies of 716 CF Uni for the outside skin and have yet to install the foam backing and inside skin. It will be spring loaded to fornm a tight yet forgiving seal against the fuselage when closed. The CF provides a nice stiff door skin.

 

I also have been reviewing the Berkut drawings for the nose gear door mechanism. I've decided to go with that setup. I made a CF leaf spring out of 4 plies of CF 703 tapes 1.5 inches wide. It fits inside the nose wheel cover and in a relaxed state deflects downward about 3 inches. When the nose gear retracts it will push it up futher inside the well. The music wire (.118 ") is attached to both the spring and the doors. They have a relief spring shape (see pic) formed into them which provides a bit of forgiveness while at the same time, exerting plenty of pressure to hold the doors shut. I'll post some pics later when it's installed. The whole concept was a bit difficult for my little brain but after revisiting the plans several times it began to sink in. (I'm wondering if I could use this method for P-51 style doors on the mains.)

 

Anyway ........ this led to my search for the proper way to work music wire. The attached article outlines in detail the procedure for removing the temper (thus making the wire softer) to easily form the proper shape. You then need to restore the temper t a hard state (too brittle for our needs) and then back it off to a 'spring steel' state which is just what is needed.

 

Yeah ....... there may be a simpler way but this is how mine will be done.

watch out making the strut too wide, besides being a better landing break it is also a better takeoff brake. with main retracts you already have a lot of take off drag

the spring steel wire that berkut used for the doors is the hinge pin material from the piano hinges. bends easy and already has the right temper. can be bough form ACS separately

[TMann]

watch out making the strut too wide, besides being a better landing break it is also a better takeoff brake. with main retracts you already have a lot of take off drag

 

Yeah .... which is why I'm stopping at 5". I was talking with Jack last night. His eRacer was 7" and the extreme version is 7.5". Same scenario .... retractable mains. I have a lot of power in my rotary so I don't anticipate any takeoff speed problems.

the spring steel wire that berkut used for the doors is the hinge pin material from the piano hinges. bends easy and already has the right temper. can be bough form ACS separately

The music wire spec'd out in the drawings is heavier than that (.125"). It works more as an actuator rod vs. a spring. It will make more sense once I have some pictures.

[Lynn Erickson]

Yeah .... which is why I'm stopping at 5". I was talking with Jack last night. His eRacer was 7" and the extreme version is 7.5". Same scenario .... retractable mains. I have a lot of power in my rotary so I don't anticipate any takeoff speed problems.

 

The music wire spec'd out in the drawings is heavier than that (.125"). It works more as an actuator rod vs. a spring. It will make more sense once I have some pictures.

its not how much power that you have, its the power you don't have if there is a power problem and it comes down like a rock and can't glide back to the field due to excess drag. the wire used on mine and Dave's is the hinge wire .089". the wire acts to keep the doors opening at the same time and aligned vertical. the coil tension spring holds the doors in the full open position and holds the doors closed when stretched over the strut

[TMann]

its not how much power that you have, its the power you don't have if there is a power problem and it comes down like a rock and can't glide back to the field due to excess drag.

You could raise the nose gear if you think it will make that much difference.

 

I'll keep that in mind, thanks. I've heard where many suggest deploying the speed brake for all ground operations to minimize damage to the prop due to rocks and gravel being thrown up by the nose wheel.

 

the wire used on mine and Dave's is the hinge wire .089". the wire acts to keep the doors opening at the same time and aligned vertical. the coil tension spring holds the doors in the full open position and holds the doors closed when stretched over the strut

That must have been an early version. I've seen that done a lot.

 

Take a look at the most current Berkut drawings and you can see it's an entirely different system.

[Lynn Erickson]

You could raise the nose gear if you think it will make that much difference.

 

I'll keep that in mind, thanks. I've heard where many suggest deploying the speed brake for all ground operations to minimize damage to the prop due to rocks and gravel being thrown up by the nose wheel.

 

 

 

That must have been an early version. I've seen that done a lot.

 

Take a look at the most current Berkut drawings and you can see it's an entirely different system.

on my aircraft I can lower the nose while the mains are still retracted. I tested to see how much the nose wheel does by itself. mine is 4.5 " wide and it changes the sink rate the same as the speed brake does. keep it as narrow as you can.

[TMann]

on my aircraft I can lower the nose while the mains are still retracted. I tested to see how much the nose wheel does by itself. mine is 4.5 " wide

 

.... mine is at 5" wide.

....and it changes the sink rate the same as the speed brake does.

That is the Idea.

[Marc Zeitlin]

... I tested to see how much the nose wheel does by itself. mine is 4.5 " wide and it changes the sink rate the same as the speed brake does. keep it as narrow as you can.

Well, yes, but the issue here is how much of a difference it makes from the standard 3" wide strut cover to a 5" wide strut cover. You have no choice but to lower the nose gear when you're landing, so you HAVE to absorb that much drag, no matter what. The question is whether you're better off with a small increment more, or whether you'd rather minimize the drag increment (and the nose gear drag altogether).

 

There are arguments either way - personally, since I put the gear up as soon as a positive rate of climb is established, it means almost nothing to me on climbout. And on approach, I have no issue with slipping the crap out of the plane, which adds WAY more drag than an inch or two of nose strut width will, so to me, it's probably an advantage to minimize the nose strut drag, as Lynn says. YMMV.

[TMann]

Well, yes, but the issue here is how much of a difference it makes from the standard 3" wide strut cover to a 5" wide strut cover. You have no choice but to lower the nose gear when you're landing, so you HAVE to absorb that much drag, no matter what. The question is whether you're better off with a small increment more, or whether you'd rather minimize the drag increment (and the nose gear drag altogether).

 

There are arguments either way - personally, since I put the gear up as soon as a positive rate of climb is established, it means almost nothing to me on climbout. And on approach, I have no issue with slipping the crap out of the plane, which adds WAY more drag than an inch or two of nose strut width will, so to me, it's probably an advantage to minimize the nose strut drag, as Lynn says. YMMV.

hmmmmm ........ okay. If Lynn fixes his, I'll fix mine.

[TMann]

I got the nose section from FS 0.0 to FS -19 floxed on tonight.

I got the EZ Noselift mounted last night so moving right along.

The rudder pedal mounts are in the floor. I'll drill those out tomorrow and mount the pedal/master cylinder assembly.

 

I'm really glad to make it past the 'Flintstone' stage (feet sticking out the front.) At least now the wuffo's can get an Idea as to which way it will move through the air.

[mfryer]

Im neck and neck with you TMann. I have started shaping nose, canard cover and the canopy frame. Ill post progress details soon.

 

Must keep working, I can't let you get to far ahead of me!

[TMann]

I attached my nose wheel and now have the nose gear install into NG-30.

I installed the rudder pedals earlier in the weekend. I can see I'll need to adjust them but that's exactly what these pedals are designed for.

 

The NG-6 was a real challenge to get in place and aligned. Glad this is the last of the swap-i/swap-out cycle.

 

About all I have left for this chapter is to put in the static port and add the springs for the strut cover and it's toast!

Much better than drawing pictures.

[TMann]

Here's the nose.

This is with the retractable pitot installed. I'll remove it for safe keeping until the end of the project.

[TMann]

Two more pics.

 

One shows those spiffy rudder pedals from Dale Martin.

The other show the trough I made to accomodate the weather seal I intend to use on these forward hatches. A sample is in the picture.

[TMann]

I had a question about how the rudder pedals are mounted.

Dale sends two strips of very thin phenolic about an inch wide and as long as the mounting channel. I riveted 5 nunplates on each side and then filled them with silicon prior to floxing and glassing over with two plies of BID. Afterwards I drill just through the the two plies and then come back with a smaller drill bit and just twist the silicon out by hand.

 

Of course, prior to this you need to sand the area where they will mount, completely flat and periodically check for square so your pedals stand up straight.

 

Pics of the nutplates are below.

[wzenheimer]

I had a question about how the rudder pedals are mounted.

Dale sends two strips of very thin phenolic about an inch wide and as long as the mounting channel. I riveted 5 nunplates on each side and then filled them with silicon prior to floxing and glassing over with two plies of BID. Afterwards I drill just through the the two plies and then come back with a smaller drill bit and just twist the silicon out by hand.

 

Of course, prior to this you need to sand the area where they will mount, completely flat and periodically check for square so your pedals stand up straight.

 

Pics of the nutplates are below.

So for my clarification they are imbeded into the nose foam prior to glassing the inside? I plan to use these as well so I appreciate all the information you have been posting.

 

Keep up the good work,

Chris

[TMann]

Chris, I do a lot of hardshelling (spread the micro slurry prior to glassing, let it cure then sand) which I did here as well. When I was ready to glass, I floxed the backside of the nutplate arrangement, pressed it into the foam (enough to account for the nutplates on the backside) then eased the edges with flox and glassed over the works.

When you are finished, the area with the phenolic/nutplates will stand proud buy a fraction and allow the rudder pedals to slide beyond the limits of the phenolic without getting hung up on the floor.

[TMann]

Well ...... chapter 13 is finally winding down.

While all you guys were living the good life up at Airventure, I was finishing my nose gear doors.

 

Pic #1: I didn't like the idea of hinges showing so I looked for another solution that would result in a flat flush appearance. The doors are CF along with the nose strut cover.

 

Pic #2: The doors opening to let the wheel out.

 

Pic #3: shows the gear doors held open via the 1/8th inch piano wire spring attacted about midway between the hinges. The hinges themselves are Lazy-Tong hinges and allow the doors to lift up, then out leaving no exposed evidence of a hinge.

 

Pic #4: I made a CF leaf spring that is attached to the inside of the wheel cover. The piano wire spring attaches to a bracket that keeps it in alignment while the gear moves in and out.

 

Definitely extra work but the end result is what I had in mind.