I have updated the Microsoft Word doc file to: B36_Build_docs_v3.doc

This file has all of the build documentation so far (a bit more than I have posted on RC Universe).

Go to: http://b36.flugmodel.net

You can also download the virtual reality file viewer at this website.

As I mentioned before, I still need to organize the layout of the design files. I will get to that soon.

Mike Roerig
[email protected]

Your airplane is looking better and better all the time Mike! I think I found my next winter project.

Mike

Thanks,

Last night I almost finished making the mount for the second main gear retract. Once that is finished I can finish up the wing mount area.

I still have a couple of sections of the trailing edge to finish before I can do the motor mounts. I am really looking forward to that. It should look good with six motors in place.

It's not a complaint, but it does take longer to do everything when I need to take the time to document. I know that I need to document as I go. If I don't, I will probably get to it 'some day'.

If you do decide to build one next fall you will have the benefit of more complete documentation. When building I discover that additional measurements need to be included like the exact location of the wing leading edge and trailing edge for the wing mount. I have a list of updates to make to the documentation and they will all get in there.

Thanks again for the comment.

Mike

I usually start by making paper templates up of the parts to glue to the wood and then cut each piece out by hand. It takes a lot of time but I enjoy it. I like to have all the parts cut before starting to build Occasionally I find a part I want to modify so I will cut one orginal and one modified in case my idea is all wet.

Mike

Mike,

I believe that if you look at the thread that precedes this one (see first post in this thread) you will find that someone told me how they used a laser printer to make their templates, layed them face down on the balsa, and then gave them a light dose of isopropyl alcohol. The alcohol transfers the image to the balsa without shrinking the paper or the balsa. The alcohol evaporates very quickly and you are left with a paperless template. It sure sounds great. If you try it out, let me know how well it works. It would have saved me a lot of time. I used a photograph adhesive to hold my paper templates to the balsa sheet as shown. If you leave the paper on the balsa for a day or two it can be very difficult to get it off. I should try out the suggestion just to see how well it works.

Mike

I have done the samething using laquer thinner instead of alcohol, but I still perfer using rubber cement to attach the paper templates. I do my cutting in multiple locations and I never have to worry about rubbing the lines off or being too light to see. Also I found I find I make few mistakes in the final sanding by having the paper glued on the piece. The templates are easy to remove and occasionally will release themselves after they have set awhile. I do cut the wing ribs in pairs so I only need one template per set.

Mike

Mike and Mike,
I was the one who mentioned transferring a photocopied image directly to wood using lacquer thinner. I go into more detail in my Duelist thread. Here's the link if interested:[link]http://www.rcuniverse.com/forum/m_7165436/tm.htm[/link]
Regards, Mike

Mike, Mike, Mike, .... Hmmmm

Anyways, great photos! First, I see that you place them REALLY close together. You probably get more parts per sheet, but my extra spacing allows me to stray a bit. My scroll saw sometimes takes an unexpected turn. For me, the wood is cheap and disk sander takes off excess wood very quickly.

I hadn't used rubber cement with my paper templates, I used photo adhesive. This adhesive made it easy to remove the paper templates if you get to them in an hour or two but if you wait a few days it can be rather difficult to get the paper off. I also noticed that if I sprayed the photo adhesive on both the balsa sheet and the paper, the paper would shrink. I recreated my ribs a second time and sprayed only on the balsa sheet.

I will take this opportunity to comment about a scroll saw blade that I just came across. It appears to be a blank scroll saw blade with no teeth that has had very durable sanding particles adhered to it. I purchased a set last weekend at Menards and they work rather slick to sand the inside edges of very small areas. For example it would work well on the notches that I saw in the parts shown in your photos. I just thought that I would mention it.

Mike

We are just broke out in Mikes on this thread! And everyone of them must be devistating good looking and intellegent!

Mike

I have tried the links to download the files with no luck, is there any other links?

Weskel

Weskel,

I will try the links shortly and provide a status update here.

Mike Roerig

I lost about a week of my spare time trying to resolve a problem with one of my laptops so there weren't any new posts.

I gave up on the laptop issues and got back to working on the B-36.

As I mentioned previously, the retracts came back from Century Jet Models and they fit nicely now. I finished up the mount for the second main gear retract. It looks just like the previous mount so I won't post yet another retract photo.

I moved on to the wing mount area.

To secure the wing mount area I needed to have the wing level and the fin vertical. I needed a large flat area where I could have the wing halves joined and set on the fuse. My workshop is a bit too small for this so I temporarily moved the B-36 to our basement. A while back I carved a semi circle in some large pieces of finger foam and I use this as a fuse cradle. With the fuse set on the foam I used a large framing square and a bubble level I confirmed that the floor was level and that the fin was vertical. I used the trailing edge of the fin as my guide. I set the joined wing on fuse and added spacers under the foam to bring the fuse up far enough for it to meet the bottom of the wing. It was not lifting the wing at all. The wing was supported by the extended landing gear. The four wheel bogey main gear has springs on it to help keep the wheels level which was almost enough support to allow the wing to stand on its own.

At each wing tip I measured the distance from the front edge of the tip rib to the floor. I was very please to see that they were within 1/16" of an inch. I believe the measurement was 5 - 15/16". I will double check that measurement and post a confirmation. If the two tip ribs had been a bit more uneven I would have removed one of the main gear retracts and added a very thin spacer under it to raise one wing tip. The main gear isn't very far out on the wing so a small spacer would make a large change in the height of a tip rib.

I examined the underside of the wing where it meets the wing mount on the fuse. I marked the area that needed a slight bit of sanding and sanded it. After sanding I set the wing back on the fuse and double checked that the fin was vertical. I was surprised that everything was right on. I expected this to take a half dozen iterations to get it right. I guess it was my lucky day.

I don't want to time out with this reply so I am going to post this and continue on with another reply.

Mike Roerig
[email protected]

Continuing on....

I was ready to secure the wing to the wing mount but before I could do that I needed to split the wing mount into two halves. Each half of the wing mount would be adhered to a wing half. The first photo shows the wing mount cut into 2 pieces and pinned into place.

I just realized a minor correction to my previous post. I used the trailing edge of the rudder as my reference point for getting the fin vertical.

To be sure the that wing wouldn't get mounted with yaw, I put a pin on the top center of the fin and measured the distance from the pin to the leading edge of each tip rib. A very slight shift of the wing was all that I needed. Reluctantly I used CA to adhere the wing to the wing mount.

Mike Roerig
[email protected]

Next I started to build up the wing mount. Excuse the obvious, but I need to build up the area above the trailing edge of the wing, above the leading edge of the wing, below the trailing edge of the wing, and below the leading edge of the wing. Below the wing was not accessible so obviously I started on the top side. I decided to start on the trailing edge. In the design I had these areas hollow, with formers and a sheeted skin. It looked good in CAD but now that I need to build this area I just don't think that it will be strong enough. Some of you may think it is a bad idea but I decided to build these areas up as solid (very light) balsa. If needed, I can hollow it out later and skin over the hollow area.

Here are a set of photos that show the progress of building up the wing mount area above the trailing edge of the wing. This is where I am at now. It took about an hour to build this area up. I will move on to the leading edge area next. I will add posts as I get these areas built up.

I will update the build doc file once I get the wing mount area completed.

That's it for now.

Mike Roerig
[email protected]

Weskel,

I just tried downloading a couple of the files and it worked fine. Perhaps the site was receivinig maintenance when you tried. Please let me know if you have any problems. I am sure that I can help you get the files. I successfully downloaded the B36_Build_docs_v3.doc file and opened it up in Microsoft Word. I also opened a couple of pdf files.

Here is a copy of a previous thread that has the pertinent info. FYI, I still haven't gotten around to cleaning up the organization of the design files. My spare time is limited.......

I have updated the Microsoft Word doc file to: B36_Build_docs_v3.doc

This file has all of the build documentation so far (a bit more than I have posted on RC Universe).

Go to: http://b36.flugmodel.net

You can also download the virtual reality file viewer at this website.

As I mentioned before, I still need to organize the layout of the design files. I will get to that soon.

Mike Roerig
[email protected]

Here are some photos of the front area of the wing mount filled in.


In the first photo I have one wing halve extended and you can see the carbon fiber wing joiners.

I will show the photos in 2 posts.

Here are the first set.

Mike Roerig
[email protected]

I'm not sure that there is much more info in these 3 photos but since I took them, here they are.

Mike Roerig
[email protected]

I have the top side of the wing mount area built up for the second wing half.

Here are a few photos showing it progressing.

Mike Roerig
[email protected]

Here is one last photo showing the entire wing and fuse.

FYI, I weighed the plane as is, with the main gear retracts installed and I am at 5 pounds 8.0 ounces. I think that I am doing all right for weight. I might be able to shave off a couple of ounces without getting too radical if I am over weight. Any thoughts on weight?

Mike
[email protected]

Nope, there's always room for one more.

Mike

It's been a busy week so I haven't had much building time.

I did get a few minutes to start shaping the blocks of balsa in the wing mount area. I only have one photo to post for now, but I do hope to finish this up over the weekend and post additional photos.

It only took a few minutes to carve off enough balsa to start getting a round shape. Sanding it to the final shape may take longer than I had hoped. I will let you know.

I did manage to figure out how I am going to secure the wing to the fuselage with a short pieces of carbon fiber tubing. I will provide an update when I finish that up.

Mike Roerig
[email protected]

I usually post when I have photos to show. Everyone likes to look at photos.

I wanted to take a moment to thank a few RCers for their help.

In an early post I mentioned that I was looking for a place to post the files for this B-36. One flyer was kind enough to create an ftp site where the files can be downloaded without getting bombarded with advertisements.

I placed my files on his ftp site http://b36.flugmodel.net and now you can download the files. I still need to organize the files, but at least they are there. Keep in mind that this is a work in progress and perhaps I released the files before I should have.

I started logging the progress of the build in a single (large) file in Microsoft Word format. My image files were very large, and they didn't need to be, so I started getting emails about the time it took to download them.

Another RCer sent me an email and offered to clean up my build file, and to split it up in to smaller ones that could be downloaded much easier. This is especially valuable if you only want to download the latest addition to the file.

And finally, another RCer sent me an email and offered to convert my Unigraphics Version 13 & 15 CAD files to DXF format so that other RCers with CAD programs can access the design files. I expect that you will see design improvements from other modellers. This RCer will also make a set of uniform plot files that you can take to Kinko's to get your own accurate prints for making parts. I hope that goes well for him because that was a HUGE amount of effort for me.

I just wanted to take a minute to thank all three RCers for volunteering their assistance.

It seems "wrong" to post without a photo so I will post a few photos of the full size B-36.

Mike Roerig
[email protected]

Here is a photo showing the wing mount area carved and sanded reasonably close to where they should be.

Mike Roerig
[email protected]

Mike I think you made the right decision on changing the wing mounting to this system. The old designed looked good on paper but I wasn't sure it was going to work out because of the complexity. You said you were at 5 lbs. 8 ozs, refresh our memories and confirm what motor, esc, and battery combination you were planing to use. You might check into Flight power for your batteries I have recently purchased their batteries and the cells are well matched and the price is very reasonable. My local shop is carrying them now.

Mike

There is a bit of humor (for me) in your question.

There are a couple of obvious questions that no one has asked and I was kind of waiting to see when someone would.

You are right. If you looked at the original design for the wing mount, it did look good on paper but when I was designing this plane, the plane didn't exist. Once I actually had a fuse and a wing built, I realized just how big this plane is and so I rethought the wing mount.

Once had the plane and wing in front of me I began to consider that 'the fuselage hangs from the wing' and I thought of it less that 'the fuse is holding up the wing'. It seems trivial, but if you take a moment to think it through it changes the requirements of the wing mount area.

On this plane:
- Both of the main gear will transfer their stress to the wing and much less to the fuselage.
- Although it hasn't been discussed, the LiPo batteries will be secured to the bottom side of the wing. They will not be attached to the fuse, so the stress of the battery weight will not be transferred through the wing mount
- My goal is to secure the radio, radio battery, air tank, and anything else to the underside of the wing

I should have the remainder of the wing mount done in a day or two so I will post photos then, and you can add your comments when you have photos to look at.

Your question about motors is one that I thought would have been asked early on.

I plan to use six of the E-Flite park 480 OutRunner 910 motors, with six ESCs (haven't chosen yet) and six Thunder Power Pro Lite 2100mah 11.1v battery packs. The batteries will be the last item purchased to I am open to suggestions. I haven't had LiPo's before so I want a battery pack and charger combination that work well together. Also, I have purchased Master Airscrew 9 x 7 three bladed pusher props.

I bought MotoCalc 8 and I am confident that I entered all of the info correctly, except that I may not be entering the cells correctly. Everything was rather straightforward to enter and select, except when it came to entering the cells. I used the wiring wizard to select 6 batts, 6 esc, 6 motors. But when I enter the cells, do I enter 3S6P (for 6 packs) or do I enter 3SP1 (for EACH pack)?

I don't recall my final selection, but if I did it right, it shows a 21mph stall speed and up to a 20 minute flight depending where you want to place the throttle. I would welcome assistance with this!

Here are my MotoCalc selections:

Eflite Park 480 OutRunner 910KV motors (brushless)
Thunder Power TP1320 cells
Prop Diam 9" Pitch 7 Blades 3
Parallel motors 6
ESC Castle Creations Phoenix 35
Wing span 114"
Wing area 1254 sq in
Empty weight (does not include motors or cells) 128 ounces
Airfoil: Clark Y
Fuse cross section: Circular
Surface finish: smooth
Landing gear: none or retractable
Protrusions: None

Well, hopefully that answers your questions. Let me know your thoughts on the MotoCalc entries, the motor, esd, and battery selections. I think that my 128 ounce empty weight is still attainable. Time will tell.

Mike Roerig
[email protected]