Dumb Insight for the Day

Be sure and keep us updated on this project. Maple: it will make a pretty noxious smoke when you use a high speed Dremel on it too.......... mk

Ooh, high speed Dremel -- I hadn't thought of that, but the bench grinder did a much more controlled job (a belt sander would have been the bee's knees, were I the kind to spend _money_ on tools).

On Sun, 30 Aug 2009 20:32:55 -0500, Tim Wescott wrote in :

You da man!

If it worked and didn't break anything, it was the right tool for the job at hand.

Well done!

Marty

This whole build process is getting a bit nerve-wracking, because of the mismatch between the gross level of completion and the fine level of completion. Unlike your average R/C plane, C/L planes -- and stunters in particular -- are almost universally built in one piece. No removable wings here!

Add to that that C/L stunters are built _light_, which means that the wing gets permanently married to the fuselage very early in the fuselage built process. This means that your plane is up to the full, finished size _permanently_ long before the fuselage is strong enough to take any serious dings. You're lofting this great, big, delicate assembly around the shop, worried that you're going to bump the stab into something and rip the back half of the plane off. I don't even have all the fuselage planking on yet, for crying out loud, and yet the wings and stab are on and the control system is fully completed. I keep expecting the dang thing to fall off my workbench and self-destruct.

On Mon, 31 Aug 2009 00:18:53 -0500, Tim Wescott wrote in :

Understood. I ended my CL career failing to finish a Ringmaster (circa 1967-1968).

I didn't know how to use dope correctly. I didn't understand the need for a base coat under the color coats. I kept painting and painting the thing with dark blue paint and never got it to look presentable.

Marty

Hey a suggestion... you do not need a belt sander, just the belt and a block of wood that it fits tightly around. I have a belt on a piece of 1" thick hardwood (probably aspen but almost any decently hard wood would work) cut to fit tightly inside the belt. It is easy to handle, lasts forever (as compared to regular sandpaper) and is quick and very accurate to use. My memory of using a belt sander is of taking waaaaaaaaay too much wood off in less than a second of operation when trying to sand some 1/8" hard birch plywood. Bob

On Mon, 31 Aug 2009 10:49:09 -0700 (PDT), Bob wrote in :

I've got one or two block sanders made out of belts bought at a flea market.

And I've cut myself many times with the X-Acto knives.

But I wouldn't go back to life without a belt/disc sander sitting there next to my band saw and drill press. Nor would I want to work without the knives.

The right use of tools takes practice. That's one of the fun aspects of the hobby.

Marty

What's the name of that waltz they played on 2001? Da da di da daaaa.... dum dum... dum dum... Glue two three, sand two three, crunch two three, cuss two three...

"Martin X. Moleski, SJ" wrote

I only have one small reservation for the choice of tools for that job.

Using sanding, or worse, a grinder to machine wood is a poor choice under most circumstances when the wood is to be joined using glue or epoxy.

The reasoning is that the pores of the wood are closed by the grinder shoving removed or burnt wood into the pores, so glue of any type is unable to deeply penetrate the wood and set up a really strong bond. The best way to prepare wood is sawing or scraping the surface.

I hope the surface area is sufficient to allow enough strength with the non ideal wood surface prep of the maple mount.

I do the same thing. Another advantage is the fact that you can rotate the belt to expose a brand new surface to use.

I get it really tight by cutting some small blocks of wood to put between the main sanding block and the belt on the back side of the block. You can really get it tight, and it also gives something more to grip the whole thing with.

On Mon, 31 Aug 2009 20:45:48 -0400, "Morgans" wrote in :

You may be right. I haven't done any tests that would allow me to affirm or deny this theory.

How much strength is needed to hold the front of a cowl on to the nose of a CL aircraft?

I can't imagine designing a highly-stressed structure where the difference between success and failure is surface preparation on some hard maple. If the joint has to stand up to a lot of force, the members should be notched or fitted into a channel in some way so that the structure is held together by the strength of the material in it rather than the strength of a butt joint.

Marty

"Martin X. Moleski, SJ" wrote

Nor have I, but I have read it in one of the forest products papers, and that was well researched.

Probably not much strength is needed, which is why I said that I hoped that there was "sufficient surface area to hold", and there probably is, even with a less than optimal glue joint.

Adding a little triangle stock is another good way to add strength to a nose joint, and it probably has that feature added, as well. I would add it, even if it was not specified, in this case, as I usually do in all my noses. I hate a nose falling off, if you know what I mean!

On Mon, 31 Aug 2009 21:55:06 -0400, "Morgans" wrote in :

I do, I do!

All of my nose jobs have come from face plants. It wasn't the glue that failed ... :o(

Marty

It'd be an interesting experiment to do -- I feel that _hand_ sanding works pretty darn well. In fact, after I got the thing roughed out with the grinder I didn't like the looks of the polished and scorched wood, so I put some elbow into it with a sanding block to expose some (hopefully) better material.

And it's just a nose ring, which has other sources of strength that being glued to the butt end of a maple stick...

Hi

I once built the fuselage for a 60" span WW1 biplane in my loft workshop. Having finished the fuselage, I sort of temporarily lost interest and the fuz languished, carefully preserved, in a corner of my loft for a year or so.

Eventually I summoned up the enthusiasm to finish the model, picked up the fuz, carried it across the loft to my workbench - and stepped straight down the loft access hatch. I arrived (unhurt) in a heap at the bottom of the loft ladder on the floor below clutching a handful of matchwood!!!!

I did eventually rebuild it and it flew very well.

Regards KGB

On Tue, 01 Sep 2009 08:57:13 GMT, "KGB" (KGB) wrote in :

OH, how awful!

I'm glad that you survived and were able to repair the damage to the fuse ...

Marty

Oh ouch! And I don't mean your injuries, either.

I can't recall building mishaps of that magnitude, but since picking up this hobby after a long layoff, I don't think I've gotten a plane in the air that didn't get some sort of crash repair before it was completed.

(although the worst ones have been self-inflicted -- I'm a design engineer, and I like to build unique things from scratch. But working out everything in detail ahead of time gets to be a lot like what I do for pay. So sometimes skip doing the detail design first and I just start building. I'll build myself into a corner, then cut out a bunch of work, then start again. It's not the "least work" way to get an aircraft done, but it can be the only way to get started, at times.)

Oh I hate the pain and agony of serious hangar rash before you finish the build.

I framed up a Midwest Super Stinker that sat in the shop for a year while I figured out how to prevent the flutter that was mentioned on almost every page of the manual. When I engineered the solution, I was covering the tail feathers and heard a knocking. I asked my 6 year old what he was doing and he told me he was driving nails. He was using the leading edge of the lower wing for a hammer.

It took another month to repair that damage and the bird flew well enough that I was able to land when it shed the top wing. It flew again after that.

Jim Branaum AM 1428

"KGB (KGB)" wrote

Wow, a double whammy! I have to think that story the prize, but I have one that might be entertaining, in a way.

Back quite a few years ago, I started to try to learn to fly RC. There were no nearby clubs, but after a few failed attempts to teach myself, I found one, and committed to the drive to get someone to teach me to fly.

I was a building contractor at the time, and carried my ugly stick type of trainer in the back of my big van along with all of my tools. There was plenty of room for both, I thought.

Nearly every trip to the field seemed to end in some minor flying mishap that required a little repair to my airplane, but sometimes only after a few good hours of fun. I would return home for the usually quick repairs, and return in the next week or so for more lessons and flying, still a happy camper.

I was getting better, and felt that soon my solo flying was going to result in a full day of flying AND returning home with an intact airplane. I was sort of right. One day I flew for hours, and finally had to return home, but this time the airplane went into the van with NO damage, ready to fly again the next time. I was on cloud nine, all the way home. Until...

I got to an intersection a few blocks from home that involved a slow sharp turn with a big deep dip in it, which always rocked the van pretty hard. This trip was no exception, but this time, my 3HP, 20 gallon tank construction air compressor came loose from its tie down, and flopped over on its side, right on top of my airplane. CRAP!

The damage was much worse than all of my minor flying mishaps of the previous weeks, put together! My wife loves to tell that story, of the complete and utter dejection I had on my face when I walked in the door. She knew that something bad had happened to the airplane, but she had to keep herself from laughing when she found out how the damage had taken place.

Needless to say, the next time I went to the field, I had the airplane stored in the van in a new place.

Hanging from the ceiling!