Scale UH-1H 450 Class Custom Build Project

[Highspeed1964]

Ok, I'm making progress again!

I have cut out all the main spars and other cross-members for the hull and main deck. It took a bit this time because I wanted to make sure and be accurate with the pieces. I cut each of the interlocking notches by hand and test fit each piece for square-ness and alignment. I then fit it all together without glue and it holds itself together pretty well!

Here are the pics:



Here are all the parts cut and loosely laid out. There are no notches on them yet, but you can see the Station Line numbers marked on both the beams and each spar. I made each measurement from the reference points (Station Line 0, Water Line 0 and Center Line for the Butt Lines) instead of measuring from one point to the next. This made a much more accurate layout.



And here they are all fit together. I still have a couple pairs of ribs to add on and the framing member for the fuel cells, but that will come next. This is all fit together without the aid of glue! This is so I can get everything squared up and true before final bonding and allows removal of components for final fit of the remaining pieces.



Here is the new assembly contrasted against prototype 1 and you can see how I had overdone the sectioning in that model. The new setup keeps the main beams as one piece and is much more structurally sound.



You can also see in this view how much I over-exagerated the curves, especially on the front of the cabin. There was also a good bit more of the incorrect curves on the lower hull but I forgot to get a picture of that for you.

I'll get the remainder of the pieces on this section next followed by building the roof again with the appropriate extension added on for the cockpit overhead - again as one piece.

I am getting extremely excited to complete this main body and move on to the tail again. Not too long and I should be able to begin putting the skin on this frame in preparation for the fiberglass molding processes.

I will cast the molds in three sections per my original plan:

1. Cockpit
2. Main passenger cabin
3. Tail boom and vertical stabilizer.

There will also be a sliding door on each side and a cowling I will need to hand craft for final assembly.

I am also coming to a final design on the mechanical assembly to mount the motor longitudinally just like in the full scale helicopter, but there are some parts I will need to get machined for that. Anyone know a good source for making small scale gear assemblies? I am looking at something similar to this:

http://www3.towerhobbies.com/cgi-bin...2AYaAvsJ8P8HAQ

That gear drive is only 4.3:1 reduction and I need one with an 11:1 reduction and prefer if it used a 10T pinion gear. I also want to have the output shaft driven by a One-Way-Bearing (OWB) internally but that is optional as I could handle that differently if needs be. I have a design in mind but need a source to produce it. Unfortunately, I only need one or two and most manufacturers will require a set minimum number to be ordered for them to even consider it.

Well that's it for tonight. Enjoy!

Highspeed

[Djentangle]

Amazing. Can't wait to see how it comes out. Subscribed!


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[swarf6866]

To get much above a 5:1 reduction, you will need a multiple stage transmission, If you want to keep the diameter of it to a manageable size anyway.

[Highspeed1964]

Originally Posted by swarf6866

To get much above a 5:1 reduction, you will need a multiple stage transmission, If you want to keep the diameter of it to a manageable size anyway.

True, and the design I have in mind uses a two stage planetary gear - almost like two partial planetary gear stages. The first stage has a Sun gear and the Planetary gears at a 2.2:1 reduction. The second stage has the Planetary gears and the Ring gear at a 5:1 reduction. The planetary gears on the second stage are directly driven (not the carrier, but the actual gears) by the planetary gears of the first stage so the overall ratio is 1st stage reduction * the second stage reduction. So 2.2:1 * 5:1 = 11:1.

You can see it in the video here:

Inside a Planetary Reduction Drive (16 min 20 sec)

I just need to scale it down to size. The first stage in my drive would have a 10T pinion and 22 tooth planetary gears. The second stage would use 10T Planetary gears and a 50T Ring gear. And just like that starter assembly, I'd like to have the one-way-bearing on the output component. It would make the remainder of the rotor drive assembly much simpler.

Highspeed

[swarf6866]

PM sent....

[Highspeed1964]

Originally Posted by swarf6866

PM sent....

PM received and replied.

[Highspeed1964]

Another day of little progress, but I finally got all the pieces for the lower frame cut out and assembled together. There is still no glue at this point but I'm ready to square it up and glue it all together. Then I'll add the runners along the edges and it'll be ready for sanding to shape.

Next will be the upper frame. Same process. A bit slower this time than the first time around as I'm actually interlocking all the pieces instead of just butting them up one piece against the other and relying on the glue to hold it in place like I did last time. Makes for a much stronger assembly and easier to keep true and square.

Can't wait to get that upper frame done and in place as this project will really begin to take shape even better than prototype 1.



Stay tuned for more soon.

Highspeed

[Highspeed1964]

I've finally gotten started on the upper frame! The main beams and spars are in place already and just need to add the ribs. I've included the upper cockpit overhead on this frame for prototype 2 so once I get the two sections done and joined, it'll have a lot more shape definition at this stage than prototype 1 did.

I've also figured out more of the mechanicals. I'll be using an off-the-shelf 4.3:1 reduction drive (check it out here) and a custom made coupling to house the one-way-bearing that will drive the primary shaft. That shaft will have the tail drive gear coupled to the Torque Tube via a 2:1 overdrive gear set. It will also drive the main rotor shaft through an umbrella/pinion gear arrangement at a 2.5:1 reduction. This will give a total 11:1 reduction from the motor to the main rotor and a 5:1 increase from the main rotor to the tail rotor.

I'll try to get some drawings together for the mechanical assembly so you can get a better visual on that in the near future. Still working out some of the fine details but I think it will be a good viable solution for going from a longitudinally mounted drive motor to the vertical main shaft and the torque tube being parallel to the motor.

Now for the pics of the day.

Before starting on the upper frame, I went ahead and glued the lower frame together nice and square. I also added in the curved beams for the nose section and will add the shaping members of that section on after completing the assembly of the upper and lower frames into one assembly as the nose frame is connected to both frames.



But the big news of the day is the beginning of the upper frame. All beams and spars are in place and it's ready for the ribs to be added in. Then the runners and sanding to shape and it's done.



As always, thanks for watching. Your views are one thing helping keep me motivated to keep up the pace.

Highspeed

[Highspeed1964]

I've gotten a couple of days behind on my updates so I'll be making a couple of posts this time. I want to keep each day in a separate post. So here's the first of two.

I finished out the framing of the root section, sanded the roof to shape and added a bit more to the lower frame. Getting close to assembling these two together! Once that is done it'll really be shaping up to look like the Huey it's supposed to resemble. I just need to sand the lower frame to shape first.

Now for the pics:

Framing all finished! The two sections are show here side-by-side.

Attachment 570438

Roof section sanded to shape. This view from the side...

Attachment 570439

...and this one from the rear.

Attachment 570440

I've also replaced the spar at FS (Fuselage Station) 211 with the actual bulkhead as I was not comfortable having this one with separate uprights. (Plus it I thought it would be really cool to see the shape on this section start taking form.)

Attachment 570441

That's it for day 13.

Thanks for following,

Highspeed

[Highspeed1964]

First, I'm not sure what happened on the previous post. The pics are there but no thumbnails and they open in a separate tab/window. But on to this post and we'll see how THIS one goes.

I decided not to perform the sanding on the lower hull just yet. I felt that leaving that structure would provide a more stable platform from which to work on this phase - assembly of the sections into the main body!

I started by cutting out the bulkhead uprights for the front-most location at station line FS 63. While test fitting it I decided to go ahead and put in a couple of the framing members for the Main Mast box inside the cabin. These are simple strips and would make for a simple install to establish the roof height and hold the rear while I installed the front members I just cut out. This allowed me to be more patient and ensure these went in straight and true.

Once that was done, I continued cutting out the remaining uprights for the second bulkhead in the front and the one at the rear of the passenger cabin. Once in place, the overhead section of the cockpit along with the curved section of the beams formed the beginnings of the cockpit shape as well. Things are looking good as you can see the attached photos.

On a side note, I've had some comments made by friends and family that this thing is starting to look like the arc (as in Noah and the animals and the flood) or some sort of luxury pleasure boat! Another comment was "I hope it doesn't leak!" (To which I replied, "I hope I never find out... it's a helicopter!") Looking at it of course, I can see the resemblance. Just thought I'd share some inside view here.



Anyway, on to the pics:

First fitting of the root section to the lower hull. Just one pair of bulkhead uprights at this point but also one pair of framing members for the Main Mast box.



A little bit lower view for GPs.



Close-up of the cockpit area.



After installing the remaining bulkhead uprights and another pair of framing members for the Main Mast box.



A view from the top. Everything's nice and squared up. Straight and true.



I've also had the original (poorly built) tail section held up to this for comparative sake. It's looking great with the overall visual but I'm holding on to that one for later to share with you all once it's ready for prime-time.

Well, quite a bit of progress aesthetically but with just a little bit of work. The bottom line is that it's starting to look like that icon of the Viet Nam war - the venerable UH-1H "Huey"!

Highspeed

[goodhunting]

Did bother to read every single post but dis you consider posting this j. The scale section. It is a great source of ideas and suggestions. Gh


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[Highspeed1964]

Originally Posted by goodhunting

Did bother to read every single post but dis you consider posting this j. The scale section. It is a great source of ideas and suggestions. Gh

In all honesty, I didn't even realize there was a scale forum specifically. Probably should have looked at that. I'll continue my posts here for the time being and perhaps link to it in that forum.

In any case, day 15 was a successful move forward. This is really the break-ahead moment where I'm actually further along in the build than Prototype 1. There are some differences up to this point, but I'm certainly pleased that I've gotten the cockpit framing completed!

In the series of pictures included in this post, you can see that I essentially followed the same two-step process as I have the other sections:

1. Main framing parts.
2. Ribs and other detail components.

In framing out the "skylight" window openings, I did discover that I should have completed this as part of the roof so that the front and side runners would have been one piece. Instead, I added in the framing afterward so there are parts that are just glued on as an afterthought. It would have been much stronger had I thought this one through early on.

None-the-less, having the cockpit all framed out gives this bird even more of the defining shape that makes the Huey such a distinctive looking airframe. This is especially true in the profile view. (Bear in mind, I have not sanded to shape the lower hull surface as I wanted to keep that somewhat flat - at least laterally - for stability purposes while working on the remaining areas of the frame.)

After taking these pics, I did complete sanding the nose to a smooth shape. However, it's not really much that it would show up in a picture. As I'm progressing through this build my skills are progressing, too! So building this section created a pretty accurate frame without much additional work to shape it. The sanding was more of a finishing step on this one.

So here's the pics:

In this first pic, I have added the frame around the "skylight" canopy windows. I have also added the lateral framing members around the nose as well as the plates that are placed inside the curved portion of the main beams.



This view shows it in a little more detail. You can also see the frame defining the main cockpit windscreens.



From this view, the door frames are more clearly visible.



The top view shows the pieces I've added a little more clearly. You can see there's not a lot of pieces in there, but adding the ribs will certainly define the shape even better. I've also started adding in the frame for the electronics bay which is installed between the two main beams.



Finally, the ribs have been added in. This gives the nose a good curved surface onto which the skins will be fastened.



And again in profile showing the distinctive look that the Huey carries.



Up next will be the main mast box as I need to complete that before I can finish up the engine bay and hydraulics section at the rear of the main body. I'm hoping to have both of these steps done for my next post. Once this is complete, I'll have the main body framing complete and then I can move on to the tail boom.

As always, your viewership is greatly appreciated.

Highspeed

[Highspeed1964]

Having completed the nose, I moved on to the rear sections of the frame. Before I could do much more on the engine/hydraulics bays I needed to complete the Main Mast box and firewalls. Boxing that out was a bit of a challenge due to the 5 degree canting of the engine/transmission/main mast and torque tube. (The torque tube will also establish the exact angle of the tail boom as it rides on the upper surface of that assembly.)

After finishing this box and firewalls, I was now able to focus on the rear-most section and get the final bulkhead in place! This bulkhead is where the tail boom will mount in the final assembly and closes off the aft end of the main body frame.

However, after getting the bulkhead in place it just didn't look right. The proportions seemed all wrong - too wide and not tall enough. So I had to figure out what went wrong. It turns out that the main beams are not actually parallel between the two rear-most bulkheads in the true design. I made them parallel on mine and this is what threw off the dimensions.

So I have to take time to rethink what to do to fix this and make a plan of attack to implement the changes. This is where I left it for the night. I'll probably have some updates tomorrow as to what I've decided and how far I get.

Two steps forward, unknown at this time how many steps back...

But here's the pictures:

The whole airframe as I've gotten it to at this point.



The final bulkhead has been attached defining the overall shape of the rear section. Unfortunately, it is the wrong proportions and will need to be redone - somehow. I'll have to figure that out.



Looking at the Main Mast box from the interior.



Inside of the Main Mast box. Notice how this area is completely firewalled off from the passenger cabin.



You can see how the main beams are parallel all the way from the front to the final bulkhead and this is what caused that bulkhead to be the wrong proportion. The beams should have angled inward from the bulkhead at station line 211 going back to the bulkhead at station line 238.



One last shot looking nose on. Notice the shaping line drawn onto the first lateral spar - you can see how the shape is... shaping up!



That's it for now. I'll provide an update when I get the rework figured out on that final bulkhead section.

Highspeed

[Highspeed1964]

Well folks, I got it figured out! I was being hindered by my current design being single piece main beams. Once I got past that, the solution was easy... just cut off the whole final segment (behind the bulkhead at station line 211) and the longitudinal struts at the center from the main mast box back and rebuild.

I cut new beam parts for this last section and angled them appropriately forming the proper width for the rear bulkhead. I also built a new center frame structure a single piece brace from the main mast box to the rear bulkhead. This added the strength I was afraid of losing when I cut the last segment off the main beams. I also got a more proper angle on this rear bulkhead so that it is at a proper 90 degrees to the main mast to allow the tail torque tube to properly align with the top of the boom. (The main mast in the UH-1 helicopters is canted forward at 5 degrees so when the fuselage is resting on the skids or hovering in level flight, the main cabin actually sits at an angle with the pilot seats at the high point.)

So I finally got on with finishing the engine bay/hydraulics section. I started by putting in the side bay walls which also closes off the third side of the upper port/starboard fuel cells. You'll see that in the photos below. This was followed by the stringers which define the curves as well as the upper decking upon which the engine and associated components are mounted.

So I've nearly gotten it ready for final sanding! I just have a few more detail parts to put in such as the transmission mounting gussets in the main mast box and the ribs/inner skin between the two forward bulkhead uprights. But this is as far as I have gotten for now.

I'm actually a couple of days late on this post, so there'll probably be another update this evening with the hull sanded and the start of the next piece - the tail boom!

Stay tuned...

After rebuilding the aft-most section, I've started adding in the engine mount decking.



I've also added in the component bay walls.



The whole thing is finally getting the final shape.



Still a few more pieces to go, but it's got that classic Huey look now!



In this perspective view you can see not only the interior of the nose (yes, it really is quite open in there for visibility sake) but also the aft/upper fuel cell pockets being formed.



Here I've added in the final runners on the rear section as well as the ribbing and interior skins between the two forward bulkhead uprights.



It's got that beautiful tear-drop shape in this view.



I've taken this one for a comparative view to a photo of a real UH-1H being restored, but then thought I'd save that comparison for next time when I have the lower hull sanded to shape.



I'll have the next set of pictures up tomorrow morning since the server has been slow today. Been getting a "Server Busy" message and finally snuck this set in. I'm making good progress since this set of pics so there'll be plenty to see.

Highspeed

[Highspeed1964]

So the moment I have been waiting for has arrived. The major milestone of completing the fuselage frame so I can start on the tail boom.

I've finished all the detail parts and sanded the lower hull to shape. It seems it has been longer than it really has, but then we are on day 18 now. (Again, the work has not been consecutive days - I am just counting the days I've actually done any work on the project.) At an average of around 4 hours per day that comes to nearly 70 hours so far. There was one or two days I put a few extra hours on it so it's probably closer to 80+ hours.

After completing the fuselage, I wanted to get right in to building the tail boom. As I've said in a previous post, even putting the original (poorly built) tail boom up against the main body gives a real good feel of what the finished project might look like.

I began the tail boom by creating a jig. This jig is key to alleviating some of the problems I had when building the original tail boom. Namely, keeping the parts straight while gluing them in place.

To create the jig, I began by using a 1/4" square strip of wood and making a mark against the rear bulkhead of the main body. I then marked out each of the locations for the remaining bulkheads using the original mark as a reference. Finally, I cut notches at each location mark to hold the bulkheads when I cut them out and shaped them to proper dimensions.

Placing the bulkheads in place as I cut them helps ensure that each successive piece follows the contours of the whole boom. So the final step in this process will be to attach the lower stringer (the boom is being built upside-down so the lower stringer is actually going to be on top at this stage) length-wise along each of the bulkheads.

So here's the pics (I've changed to putting the comments as captions below each picture):



The overall look of the main body. Notice the contours of the lower hull is complete now.



Viewing it from the rear shows how the shaping completes the whole look of the hull.



And again this shot from the front also shows off the complete look of the shaping.



This may be the only time you see this thing upside-down! Since this is a scale build it will only be flown scale. But I wanted to show the hull shape in its' final form.



And here is the promised comparative shot, compared to...



...a real Huey undergoing restoration at Northwest Helicopters, Inc. in Olympia, WA.



To begin the build of the tail boom I started with a square strip of wood and marked the location of the main body rear-most bulkhead.



I then marked and cut notches for each of the tail boom bulkheads.



Having a jig helps hold each of the bulkheads in place until I get the stringers and longerons in place.



Adding each of the bulkheads as I cut them allows me to ensure each successive piece is the appropriate size to maintain the contour of the whole boom.



Now that I have all the bulkheads cut and placed, the next step will be to install the lower stringer, placed temporarily here for this final shot for today.

And again, thanks for watching.

Highspeed

[Highspeed1964]

So first things first, I got a couple of new toys for this helicopter in the mail today! Motor, ESC and Lighting Kit. (Lighting kit not pictured in today's post.)

Had a chance to temporarily put some of the components including the motor and ESC for a test fit onto the main body frame. With the battery going under the floorboard forward of the main mast box, also taking into account there are more mechanical assemblies and electronics components going into the engine bay area, and the fact that the tail boom with its' mechanical assemblies haven't been attached, I think the fore/aft CG is going to be just about perfect! As it is, the CG is about 1 inch forward of the main mast. Not bad.

So since I spent some time playing with these new toys I didn't get much else done on the actual build. I DID permanently fasten the lower stringer on to the tail boom by cutting notches in the bulkheads and aligning the strip in place; fastening it with glue after ensuring each bulkhead was properly aligned and angled.

Once I got that completed it was time for a test fitting of the boom to the main body. WOW! This thing is going to rock!

So on with the pictures for today.



The mailman brought some goodies today!



Testing placement of some components including the new motor and ESC to check fore/aft CG.



This is approximately where the motor will sit in the completed model.



Ain't it PRETTY?!!! (And yes, that IS the correct angle it will be mounted at.



First test fitting of the new tail boom. The tail boom still has some work to go and I haven't even begun the vertical stabilizer yet.



The Huey doesn't look so much like a boat anymore! (I've been told by more than one that the main body looks like Noah's Ark.)

Next time I hope to have all the stringers in place, ready to mount the longerons after installing the vertical stabilizer spar and other framing components.

Until next time...

Thanks for watching.

Highspeed

[goodhunting]

Love this project....
Gh


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[Highspeed1964]

Made some good progress on this session. Finished out the tail boom... minus the horizontal stabilizer. I'm not sure that would be considered part of the frame as it is a moving part but there are framing members within this component. I have added the support plates on the tail boom for the horizontal stabilizer so it can be added.

First step in this section was to add the remaining main stringers so I could get the boom off the building jig. I needed to remove the jig so I could put the main spar for the vertical stabilizer since the jig was blocking the opening this spar protrudes through. Once I got the jig removed, I installed the main spar and began installing the rest of the components.

I continued building the rest of the vertical stabilizer and then added the longerons (long flat strips along the length of the boom) and remaining stringers. It was quite a successful session this time around and I was excited to be able to match up the boom to the main body for the first time without the jig.

It looks amazing to me, but then I am the proud builder so there's no bias there!

Anyway on with the pictures:



Got enough parts installed to pull the tail boom off the jig and begin working on the vertical stabilizer.



Tail boom is complete!



Nice straight lines. And yes the vertical stabilizer is supposed to be curved like that.



Front view of the boom.



Finally able to mate the boom to the main fuselage.



It adds a lot to the Huey look.



This is one bad a** looking heli and the model looks just as awesome!

Hope y'all enjoy this set!

Thanks for following.

Highspeed

[macdad]

You are an amazing craftsman. Thank you for sharing your project with us. I could never do something like this, which make me appreciate what you are doing even more. Can't wait to see how you install the electronics and mechanics in this bad boy!

[Highspeed1964]

Originally Posted by macdad

You are an amazing craftsman. Thank you for sharing your project with us. I could never do something like this, which make me appreciate what you are doing even more.

Thank you, kind sir!

Originally Posted by macdad

Can't wait to see how you install the electronics and mechanics in this bad boy!

Me too! I do have some ideas, just have to work out the position of the servos mostly. I'm going to be using a planetary gear reduction drive and an umbrella gear combo to mount the motor in the correct scale location and orientation. Probably do something in the neighborhood of 13:1 or 15:1 overall reduction for good scale flying head speed.

Highspeed