splinterz25

Guys are you understanding where I'm going w/ the removable booms yet?
I mounted a 64" 1/4" x 1/4" spruce stringer on each side of the wing crutch tonight and finished drilling, routing, cutting, sanding all of the former pieces tonight then put her together.
Next I need to check the orientation of the firewall and make three notches for the stringers to go through to be flush w/ the face of the firewall.


And then drill for the two 3/16" oak dowels I placed one in the front mount in case you didn't understand what the I've been talking about


there's hasn't been very many questions on this build I guess because there's nobody else besides martin building one?


Bruce

splinterz25

These are great questions
I had a follower ask,

1. The boom attachment method you are working on, will the engine/fuel system be integral with the boom, so that when you rig her for flight you fit and lock the boom complete to the main plane, then make the servo connections? ( I have seen large models where the boom is complete and is slid onto two large diameter aluminium/carbon load carry-through tubes between the center wing panel and the outer wing panels.)

2. When transporting your BV 138 to the lake/flying field will she be loaded in a trailer or travel box for your truck/van?

MY REPLY:

The Booms: My plan is this the tail section will be the ELEV,STAB,FIN, & RUDDER.

The ELV: will have two low profile MG servos w/ rotary systems w/ there wires running out each side.

The RUDDERS: will each have there high torque MG servos in the removable tail section; this part I'm still working on but I have a few ideas how to make them work w/ out having the push rods leave the fuse.

WIRING: When the tail is connected together to the booms so will be the servos and lights w/ a 9 pin plug or sim. they will automatic plug in as bolted together.

WIRING / BOOMS HOOKING TO WING: Again I would like to have a plug when the booms are bolted down they will plug right in as the bolt tightens up.

FUEL TANKS on the BOOMS : The engine will stay mounted hooked to the fuel tanks: there are hatches on the scale plane just behind the cowlings I would like to make all three accessible the two on the booms w/ fuel dots the center hatch fuel dot and charge port.

WING FLOATS: I want to make these clip on and off quickly.

FUSE: I'm really thinking about putting a bilge pump in the very bottom because you know water will get in some how no matter what you do.

TRANSPORT: I was just thinking tonight that I was going to have to buy a trailer

I want to make this so you can assemble it in less than 1/2 hr.

I hope I've covered it all; but if not keep the questions coming the help me thing or catch things I've missed.

And if there are any reasonable suggestions they are always welcome.

Bruce

splinterz25

Alright today I wanted to get the boom connected enough so I could take it off like it will do when it's finished.

I started by trying to keep the bottom aft boom stringers as long as I could and and
I wanted former 5a to be up against the aft main spar; these formers I've created there's not one on the drawings.

I fact there are no formers on the drawings Gene has these booms being stick built w/ small curved pieces on top of each frame work.

Anyway I made some good progress but former 5a will have to be moved back because when you lock the tongue on the firewall and lower it to the aft of the wing it ends up on the wrong side of the aft stringer.

Have a look at the photos they explain way better than I can,

No worries it's all fixable and I've a great deal yet to figure out before all the pieces go over the drawings; they wont match in places because of my mods.

But will help me keep everything straight and the angles correct there will have to be X bracing added I'm thinking 1/4" x 1/4" balsa here to help w/ the weight.

Also I will have to do more in the center of the wing where it mounts to the fuse for strength w/ some kind of bracing; these booms and there engines will put a great deal of stress on that area.

Check it,

Bruce

splinterz25

this morning so I tracked down the T-nuts that I had but couldn't find bolts so off to the store; of course they didn't have any to fit my T-nuts.

So I went one better and got 10-24 x 9/32 stainless steal T-nuts and 10-24 x 2" countersunk round head phillips tipped bolts.

I changed the former 5a by adding an angle to it and then tweeked the aft hold down / T-nut; if you look closely you'll see where I've notched for the 1/4"x 1/4" stringers in the edge of the 1/8" 9 ply w/ the holes drilled in it.

Just take a look it's easier than me explaining and if you have any questions please ask.
Sorry about the photos being blurry I have to go back and adjust my camera.

Bruce

splinterz25

Well I pulled the drawing off the wall laid it out on the table covered them w/ wax paper placed the boom on after gluing my mod. formers so the would be in there correct places.

Every thing lined up great then I went through and glued the rest of the formers plum & square from front to back when I got to the back I had to drill for the carbon fiber tubing; I tried to show this step by step in the photos.

I've had someone ask to show how to get the wing tubes to fit properly so they won't bind this is how I will do those as well, one at a time marking w/ a pencil;
BUT I drill both sides at the same time this way if you do get any variances there in the same place making both sides look the same.

I also put together the Sullivan fuel tanks and slid it in to position; I'll do more w/ these later on during the build; but they had to go in now.

There is two #12 formers there both 1/8" 9 ply; this is where the tail section will break, all of the formers from #10 back still need to get lightning holes drilled in them.

Next I'll drill those holes & start gluing 3/16" x 3/16" balsa Diagonal braces down the sides.

Check it.

Bruce

splinterz25

Well I kept on working this afternoon and got the 3/16" balsa cross braces on down to where the tail section will be removed; the whole aft end is unglued still.

Check it,

Bruce

splinterz25

Alright I was up early and moved on to the aft wing tube hold this really locks this boom in and I may not even need the two front dowels?
Check the photos they show it better than I can tell it.

Next I need to work on the aft tail section T-nut lock/ hold and then build the second boom; I've been making my parts for the second boom the whole time so it should go much faster, also I know what to expect.

Check it,

Bruce

splinterz25

The plans call for 1/8" every where; But I just bought some 1/16" the radios on the top of the booms is very small I may have to do two layers of 1/16 bent over and glued to each other.

It's a lot of 1/8 balsa I have 40 sheets 4"x 36" to get me started.

I haven't made any great progress since this morning when I did the aft wing tube locking to boom on.

Since then I've been looking at the rudder servo and location I have two
HS -225 MG servos that might work.

Iv'e ordered a bunch of supplies and thy should be here next week.

Now I'm going back and looking at ALL the drawings there's NO PROFILE of the vertical stab ribs, just the center cross section?

Bruce

splinterz25

Well I worked on the internal control horn for the rudders today
and I think it'll work

I've cut out four hinges from some fiberglass sheeting I made a while back; they need to be drilled and a nylon bushing added where the steal music wire goes through.

I need to run a test w/ the radio and then build the rudder; I'll see if I can make a short video tomorrow w/ it working.

I think I'm done for the day,

Bruce

splinterz25

Well I worked on the hinging this morning and it's a bit fiddly but I think I got it lined up correctly; the rudder won't move to it's full motion until I sand in the front radius.

Have a look,

Bruce

splinterz25

Got some more details added on this evening; added structure / gussets and lightning holes as well as rough shaping the rudder.


I added some blocks for the carbon fiber tubes to seat in when in place as well as blocks for the hinges, I still need one on the top hinge.


There's quite a bit of small things that need attention but it's starting to shape up; in the morning I push to get the actuator set and running w/ the RX.


There's one thing I've been noticing and that's the center section still needs more structure; when you put pressure on the tail section it moves the far side of the wing very easy, I'll have to add a tube in there and maybe some more stringers?


Bruce

splinterz25

Okay here's the video of the rudder actuator test run; I would like to get
more range of motion and think I can w/ some more sanding to remove more on the LE radius, but check it out she's working.


http://www.youtube.com/watch?v=UG1yw5DLd6I

splinterz25

Alright before moving on I wanted to get the rudder setup a bit better; I first removed some of the nylon servo wheel and ran a test, this worked much better.

The clevises were hitting on the inside; the other thing I did was, I didn't think the nylon wheel would hold up very well.

So I had some large composite wheels / horns that I thought would be much better suited for this application;But they had to be modified first.

The other things I did was enlarged the hole where the push rods pass through the TE of the virt. fin, then reinforced the sides w/ carbon fiber threads/ tape.

Also I added a piece under the servo to help reinforce the rib the servos mounted into.

In the actuator box I made more clearance for the clevises and added there retaining clips.

Nothing is glued in solid yet; but I made a little better video, I still need a lot of work on these videos yet.

CHECK IT.
https://www.youtube.com/watch?v=HOQ89E-Rp3w

splinterz25

Now this afternoon I started on the part where the tail breaks apart.
There will be an ALUM. clip that will go at the bottom locking in a groove like the boom did.

There will be a bolt running through the ALUM. and 9 ply that has been glued in to the former and will thread into a T-nut that's sandwich 1/4" ply, that will be notched to the stringers and the bolt will pull all of this together tight.

This only holds the tail from coming off; the 2 long carbon fiber tubes are the strength of this hole system, that's why I made sure the were very tight and seat snugly.

I post photos when I have it a bit farther along.

Bruce

splinterz25

Alright today after running to get some supplies I was able to get the removable tail completed on one boom, the other side will be the same way w/ the stab. / elv. connected permanently in between.

I picked up 12- 4" clamps a countersink set and a laser level; I'm not going to try and explain what I did just look and if you have any questions feel free to ask.

Check it out,

Bruce

splinterz25

???????????????????? I'm not sure that was meant for me???????????????

splinterz25

Well I was up very early this morning and cleared off my work table and started
to assemble boom #2, I'm hoping since most all my parts are made I should have a complete
or near complete boom this afternoon sometime.

Bruce

splinterz25

Well I didn't get as much as I had hoped today.

BUT the good news is that a friend found a guy to buy one of my custom hobby cars.

This puts me well on my way to getting the LASER ENGINE.

I can't make up my mind if I should get the 155 or the 180 they'er both suppose fit,

Jon over at Laser says the 155 should fly it and the 180's only a bit more power?

There telling me to get all three engines the same size like the scale plane.

BUT I LIKE THE IDEA OF HAVING A MORE POWERFUL CENTER ENGINE

JUST IN CASE one of the outer engines cuts out during flight.

I only want to fly it in a scale like manor and just hope the engines will get it out of the water w / out to much trouble.

So because of this I'm leaning toward the 180.

And there's not enough room for the 160V.



I GAVE THE GUY A GOD DEAL ON HER ($200) SHE'S 6 YEARS OLD BUT IN GREAT CONDITION AND HE GOT ALL THE BATTERIES & CHARGERS AN EXTRA BODY.


HERE'S MY START ON BOOM TWO.

splinterz25

Alright today I glued some of the formers to the second boom then before I went any farther I wanted to check the fit of the aft wing tube through the boom/ fuse.

So this meant more cleaning up and turning my table around so I could check this;
and it looks spot on so far, I'll also mount the front tongue mount while I have it in this position.

She's looking bigger and bigger; the table is 5' long.

Time for a quick lunch then back down stairs to get some more glued up.

Bruce

splinterz25

Okay if there's anyone taking notes on this build so they can build one w/ removable booms; there's a few photos in this batch that show you making the aft wing tube passing through the booms and what I did.
These parts you'll have to make your selves.

There's a few things I've now discovered.
First: the very front mount for the tongue is CRITICAL in it's placement / pitch; I think I may have to adjust my first boom?

But having no INCIDENCE angle shown on these drawings do make it challenge.

Second: the wing chord is so THICK I have to put the INCIDENCE meter out at the edge of the wing to get a reading.

I knew I was going to have to get a longer bar for the incidence meter.

But near as I can tell it's at 5 degrees; my table is level and the main spars are sitting on a platform / ply on edge, that has all pieces the same height.

Some body correct me if I'm wrong this seems to be what the full scale plane would have had?

It's not nessesarly what you would need on a model?

My original thought was the two engines on the booms would be mounted straight
w/ no pitch / angle at all; the center engine would get the 2 degree angle.

The first boom I mounted is following the wings incidence almost 100%

The second boom is matching the center section where the center firewall will mount; this is 90 degrees off the top of the fuse at the cockpit.

Any help or intelligent suggestions here will be appreciated.

Here's what it looks like,

splinterz25

Well I've had to do two things.

One: is my incidence meter has to be modified to work w/ this thick chord wing;
I'll show this in a bit.

Two. I've raised the aft part of the center section out of the notches cut where Gene has them on the drawings and even 1/8 higher to get the incidence to 3 degrees; I'll double check this after I change the incidence meter.

The other thing I'm doing is adding an aft 13/16" x 24" carbon fiber wing tube in the aft center section.

And since I have to lift this grove out of the fuse former I'll make a new piece that will hold this section up and have the carbon fiber tube run through it as well.

Good thing nothing is glued yet.

The other thing is that the firewalls now move to a 90 degree to the fuse
this is where we want them; there'll be no angles what so ever on the boom engines left, right, up or down.

The center engine may need a few up degrees?

Bruce

splinterz25

OKAY MARTIN AND ALL...I made the changes to my incidence meter raised it
by 1 1/2" I had some black plastic lying around that happened to match the meter.

I sliced some 3/4" strips and making sure the were both parts of the meter were the same size then I glued them up.

Then it was on to the changes to the planes incidence; with some fanagueling and luck I was able to get a 5/16 carbon fiber tube into the aft section where I wanted it.

Next I made a piece to capture the carbon rod and lock on to the fuse while holding the aft end of the center section of the wing to the correct height.

I've raised the aft end 5/8" to bring the wing to 3 degrees incidence.

I also cut 1 1/2" x 1 1/2" pieces of balsa w/ a 5/16" hole drilled in them to hold the carbon fiber tube.

Nothing is glued yet; also I've made it so the center section can still come out so I'll be able to have it on the bench while building the wing tips, this will be better for lining up the wing tubes and angles of ribs #6.

Once I'm sure this is where I want this to be set I glue the carbon tube in place; this will make it more rigid but I may still but a 1/8" x 1/2" spruce stringer over the flap hing line to be sure.

Check it out,

splinterz25

you should check out my thread on RCSB.

http://www.rcscalebuilder.com/forum/...69&PN=1&TPN=44

The other thing you may not see or notice is the props/ engines on the booms are forward of the center engine; on this model it's about 3/4" back from the booms engines/ props.

Gene points this out on the drawings; I'll post a photo of his words.

Two of those photos show all three engines w/ three bladed props it may have had to do w/ cockpit noise and vibration so they used a four bladed prop?

Okay I got back into it today before moving on I wanted to get the aft stringers cut in; I changed my mind and added a 1/4" x 1/4" stringer to each side along the top of the flap hinge line.

While I had the center section of the wing off on the bench I sanded all the ribs flush w/ the main stringers, touched up any places that needed it and added glue where it was needed.

I also cut and sanded all of the ribs LE, and cut the LE sub edges; these sub edges and the stringers will be glued in place once I have the center section just where I want it, after many measurements.

The other thing I did was the aft edge had to be lifted out of the locking groves that Gene had me cut in ribs # 1 so I've made another lock that will slide around the fuse formers besides the one that holds the carbon tube, and would still like to get one more set if possible.

splinterz25

Okay today what I did was before I cut the formers for the 24oz tank to fit I wanted to come up w/ away for the firewall and all the formers to get tied together; but I wanted to keep it strong and light.

Here's what I've come up w/ so far I made sides out of 1/16" 9 ply they will be recessed into the formers and firewall; I'm sure I'll have to do some bracing but this is much lighter than using spruce stringers, the formers & firewall still need to be notched to accept the sides.

This also will put the fire wall at 2 degrees upward thrust; the aft section of the sides will be extended and will tie into former #13, then because there in set the 1/8" balsa sheeting will cover over making it even stronger.

Check it out I think you can tell where I'm going w/ this,

Bruce

splinterz25

Okay the fuel tanks is cut in and an aft mount made and installed I'll make the front one when I get closer to sheeting the sides and mounting the engines.

I've also finished the sides groves & splines as well as an dove tail extension on each side back to former #13.

When these pieces are all locked together you can't believe how strong the whole top becomes w/ out any glue

The 2 degree up thrust I was trying to incorporate into the firewall seems to have straightened it self out some how?

But I could still change it if need be or just shim the engine mounts.

I'm getting quite a few people telling me not to do up thrust ; but I know a triple engine plane is set up different than a twin or single also this is a water plane and needs to get on step to get up out of the water.

Check the days progress,

Bruce