#1007 Model Airplane Building Clinic

[offtom]

Well, I finally made up my mind on what to build for this little project. Actually the wife made it up for me. Once she found out I already had the electronics I needed for this project she decided this was the build I was going to do. I really was leaning towards the 262 and ducted fans. She says I spend too much on this hobby already.

(I haven’t told her about the vacuum forming table I’m going to have to make to complete this build yet )

Since we have a cold front coming through, fall is settling in, and we were supposed to start a couple weeks ago on these projects, I thought I’d get started.
Anyway, the Martin B-10 is as you can see a very unique looking plane, and I do like unique looking planes. It’s also a multi engine which I also like hence the reason it was on my short list.

[offtom]

The plans I found on E-bay awhile back from Uncle Willies. The plans are for a control line version of the model. With a little work and imagination I think I can get an RC version out of them. At least that’s what I’m hoping for

[offtom]

Got the work bench cleared off last week which was a day long endeavor. Amazing how much “Stuff” one can fit on a workbench. I did get an area large enough to work on ready and many of my tools rounded up yet again for this project. I’m sure I’ll find the others I need as this project progresses

[offtom]

Well, when I got the plans printed while trying to decide what to build, I only got one copy made. Usually I get two so I can cut the templates out of the second one and glue them to poster board.
Since I only have one set, and the boss looked at me real funny when I wanted to go get another copy printed
I decided to go to plan B, Tissue Paper

Yes, that’s what I said “Tissue Paper”. You know that foo foo paper the significant other uses when putting gifts in gift bags. I have tried using carbon paper in the past to accomplish the task of drawing templates, but it just never worked real good for me. I could do that acetone thing I’ve read about to get them transferred directly to the wood, but then I only have the one set of plans. I don’t think I want to be smelling that odor for an extended amount of time. Awhile back while working on a B-17 with plans that were too large to get a second copy of at the local office supply store, I discovered tissue paper. It is much less expensive than tracing paper and really not hard to work with.

And it comes in many different colors if one so desires.

Yes tracing templates is a little work, and makes one appreciate Laser Cut kits a whole lot more, but I don’t mind. I always did enjoy working with my hands and building.

So I set about tracing the templates to my tissue paper. Once done with this I have some poster board I glue my tracings to. I used Scotch 77 spray on adhesive to do mine. One piece of advice I might offer if trying this is don’t try to glue a large piece of tissue paper down. It get’s really tough trying to get one large sheet down smoothly, trust me I know. There is nothing worse than having to sit down and re-trace the templates again. Cut your sheet of tissue paper templates into smaller pieces then glue them down.

[offtom]

Why the templates one might ask??? Seems like a lot of work. Well, yes it is but, when it comes time to repair the plane, which does happen eventually, you’ll find that process much easier because you have the templates ready for the repair process. It’s just something I like to have.
Once done with this step I cut my templates out and place them on the plans. Helps me make sure I got all the templates traced and cut out. In this case I found I missed one of the wing ribs while getting my templates ready.

[offtom]

One thing I did notice about these plans is the wing construction isn’t what I’m really used to. The outer portion of the wing panels had no wing spars. The plans called for the ribs to be glued to the leading and trailing edges, but nothing else. I do not like that, so I decided to put a 3/16’ spar about a third of the way back from the leading edge, and a 1/8” spar towards the rear on the top of the wing panels. I’m also going to run a 3/16” spar on the bottom the wing panels. I drew the lines on the plan where I wanted to place these, then marked them on my wing rib templates.

[pd1]

Nice subject.

Paul

[rcers]

Originally Posted by offtom

One thing I did notice about these plans is the wing construction isn’t what I’m really used to. The outer portion of the wing panels had no wing spars. The plans called for the ribs to be glued to the leading and trailing edges, but nothing else. I do not like that, so I decided to put a 3/16’ spar about a third of the way back from the leading edge, and a 1/8” spar towards the rear on the top of the wing panels. I’m also going to run a 3/16” spar on the bottom the wing panels. I drew the lines on the plan where I wanted to place these, then marked them on my wing rib templates.

I get it - but I think we have been over engineering models for many years.

Case in point - was admiring a full scale DC-3 restoration and I was amazed to see that the wing panels of the DC-3 are actually just bolted on (at the skin with a flange). There is no spar outboard of the engines - zilch, nada, zip. I could not believe it! And those are HUGE wing panels on the DC-3!

Granted it is a stressed skin - different than an open wing structure you are using but I am confident you would be just fine. That covering adds amazing strength and flutter should not be an issue if your keep your speed down.

BTW - great build subject!

Mike

[road king 97]

Originally Posted by rcers

I get it - but I think we have been over engineering models for many years.

Case in point - was admiring a full scale DC-3 restoration and I was amazed to see that the wing panels of the DC-3 are actually just bolted on (at the skin with a flange). There is no spar outboard of the engines - zilch, nada, zip. I could not believe it! And those are HUGE wing panels on the DC-3!

Granted it is a stressed skin - different than an open wing structure you are using but I am confident you would be just fine. That covering adds amazing strength and flutter should not be an issue if your keep your speed down.

BTW - great build subject!

Mike

The only one i know of not over engineering planes and plans is Ivan ,thats why his fly so nice and scale like.because he desighns for a very light structure he has many people building them all over the world . joe

[Stevephoon]

Cool Plane Tom.... I'll be watching too!

Steve

[offtom]

Well, one thing about building from plans is it takes just a little longer than some of the builds you other guys are doing. Sheesh! Almost looks like some of those planes are going to be flying by this weekend. Kind of makes me feel like a snail at the pace I’m going, and I didn’t get too much done during the week here.

Did some soul searching after my last few posts and I’m going to heed the advice about not over engineering the thing. I decided against adding the wing spars and sticking with the original plan.

Since this is supposed to offer ideas for builders here’s, a couple I use.

First, for my sharp cutting instruments I found a safe place to store them on my work bench. An extra piece of foam does the trick well. It keeps the Exacto from rolling off the bench and piercing my big toe.

It also keeps the single edge in a spot very easy to find. One problem I always had was after using one I'd lay it on the bench where inevitably it gets covered by something and temporarily lost. It used to be by the end of a build, while cleaning up my mess, I’d find several of the single edge blades in their hiding spots.

[offtom]

I don’t have one of those fancy self-healing cutting mats I’ve seen in pictures of other builds on these forums. I use a piece of foam to cut on. I’ve done a few builds on this one already and it’s still in pretty good shape. I could probably do a couple more builds on this one before I have to worry about flipping it over to start using the other side.

The boss said I have to try being a little more “Frugal” with my hobby.

[offtom]

I finally started with the tedious part of a plan build. Transferring the formers and wing ribs shapes to wood.

I always find it amazing how many little parts there are in these planes we build ……. Fly ………. and crash.

[offtom]

Now getting the parts cut out. Some things I’ve learned over time.

When I used to cut my parts out using an Exacto knife or a single edge blade, I very rarely cut the edges at a 90 degree angle. Second on a plane like this, with all the round shapes, cutting these curves with a blade could get very frustrating very quickly. Thank goodness for internet forums like this, I learned a few tricks.

I read about using a jig saw to cut the parts out leaving a little extra wood around the edges. Once this is done one sands them down to shape. It made sense to me so I tried it on a build. I liked the outcome. Nice straight edges, and my round shapes came out very nicely.

[offtom]

Cutting the cutouts in the formers and wing ribs for stringers and spars is always a fun but very necessary task.

Cutting cross grain if the distance isn’t over a half inch from the edge of the piece to the bottom of the cutout I use my single edge razor for the cut. This entails rocking it back and forth gently pushing in until I reach the inside line. Once this is done on both sides of the notch I take my Exacto. Once this is done, a little cut with the grain on the bottom line of the notch, the wood just pops right out.

[offtom]

Pieces where the grain runs from the outside edge of the cutout to the inside needs just a little more work. Cutting cross grain in a quarter inch space without damaging the piece is not an easy task with an Exacto alone. It can be done, but I find the outcome isn’t always really neat. When I do it anymore I use my jig saw. First I cut several lines from the edge of the piece to the bottom line of the cutout. Once this is done I take my Exacto and again with a couple little cuts I’m able to cut cross grain in the small area without problems or gouging into the wood.

[offtom]

Well, I’ve managed to get a good portion of the tedious work out of the way. I have just a few more cuts to make on a few formers and ribs and I should be able to get started on something serious this weekend.

[road king 97]

I think you made to right choice not changing to much on the plans ,i thought about changing many things on my solent build but after thinking about it i knew all my changes would just add extra weight that a electrict plane does not need. joe

[stuart]

wow!i am totally subscribed to watching your build,like you our weather is getting colder by the day. won't star building here in NJ for a while as i hope we have many more flying days..lol.

will be watching your scratch build closely as i never tried this type building and find it very tempting......[jk,i'm to lazy]





by the way the choice of plane is awesome!!!

[offtom]

Well thanks Stuart, I hope I can keep it entertaining for you. I always look at putting off a build like this as not being lazy, just finding the time to do one.

They can be very time consuming.

[offtom]

Well, not as much done this weekend as I thought I might get done, but then building like this sometimes presents one with challenges.

I did get all of the cutting done on the formers and ribs.

When I set them on the plans to make sure I got them all cut out guess what??…………. yup………Missed one.

JustOne of those challenges I was talking about.
　
Dig through my templates and find the one I forgot and finished the job.

[offtom]

All that done I spread my plans on my building surface. It’s not as big and fancy as a magnet building system, which does look like a system I would enjoy using, and it’s not a soft wood. It’s very simple and something I’ve used for many builds over the years. A 2’ by 4’ piece of 2” foam board. As long as my work table is straight and level, so is my building surface. Plus it accepts T-pins very easily. Once the plans are down I use wax paper to cover them so I can start a build.

[offtom]

Now to get started……..Like any good ship, one must lay the Keel first, right??

[offtom]

Keel set, now to start test fitting my formers. Believe it or not, most all of the plan builds I’ve ever done, the formers, or ribs, though printed on the same sheet and scale as the plans themselves, always need a little extra trimming to get them to fit just right. Luckily I’ve found most of the time I just had to trim to get them to fit rather than trying to get a template out and trying to figure out how to make a piece bigger. Measure twice, cut once right.


The fun thing about this part is seeing the plans start to become 3D. Always a little exciting for me.

[offtom]

While test fitting the formers it dawned on me, These plans are for a gas control line model, and I want to convert them to an electric RC plane.

Looking at the build, and remembering my B-17, I’m thinking the battery is going to have to go as far to the front as I can possible get it to get the plane to balance. I’m thinking with the motors I’m planning on using for the build a 22oomah battery would be fine. Now then, trying to figure out where it will go.