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Old Feb 25, 2008, 01:30 PM
B for Bruce
BMatthews's Avatar
The 'Wack, BC, Canada
Joined Oct 2002
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Very much minimalism.

I always covered flat and then snapped the joints at the dihedral breaks and "repaire" the joints with a little dab of full strength glue pushed in with a scrap of stick. Yes this leaves a little scallop of loose covering but it never hurt the flying at all. Everyone else did it the same way.
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Old Feb 26, 2008, 03:26 AM
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erich's Avatar
Holden , Massachusettes
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Thanks Bruce (hope you don't mind). If it's good enough for everyone else, it's ok for me. Besides it's gotta be a lot easier to add the covering on a straight section then the way I been doing it....cheez.

Made up the angled wing mounts. Reinforced the glue joint after breaking 3 of em. Used a fine sewing thread covered with a little ambroid. Made forward motor stick by sanding till it was thickest in middle and tapering evenly toward each end (pretty much the demensions mentioned in Ron's book). Added a Harlan motor bering, offset with about 2 deg left thrust. Wound some threads around here too and set with ambroid. Bent up a tail hook with a small gussett underneath and reinforced with some tissue and ambroid. Added tail stick (making sure both were in a straight line as viewed from the side) and reinforced that with tissue and ambroid.

erich
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Old Feb 27, 2008, 06:39 AM
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Holden , Massachusettes
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Glued stab and rudder to motor stick. Tilted stab to match angle of left wing. This seemed pretty easy, but took a little bit of doing. Adding rudder was fairly easy though. Took forever to get the wing posts lined up properly with wing. Nothing but angles on this plane.

erich
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Old Feb 27, 2008, 10:43 AM
Free Flight rubber flyer
South Carolina
Joined Mar 2005
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Quote:
Originally Posted by erich
Glued stab and rudder to motor stick. Tilted stab to match angle of left wing. This seemed pretty easy, but took a little bit of doing. Adding rudder was fairly easy though. Took forever to get the wing posts lined up properly with wing. Nothing but angles on this plane.

erich
Should I feel weird that I just eyeball everything on mine? Is it odd that I don't build in any stab tilt, but simply twist the boom to get proper stab tilt during the trimming process?

You people that use all those jigs scare me!
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Old Feb 27, 2008, 11:31 AM
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Holden , Massachusettes
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The jig is just to hold the fuselage, sorta like an extra hand. I got the stab tilt in the same silly way you do, by eyeballing it. I just found out recently, about bending and twisting balsa to make it hold a new shape. Pretty cool. Hey, I'm not slow.... only took me 20 years.

erich
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Old Feb 27, 2008, 07:45 PM
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Joined Jul 2005
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The indoor experts usually use saliva to wet the tail boom and bend/twist it to the required angles.

So I normally build the tail booms and stabs straight, and twist them during initial flight trimming to suit the size of your flying site, hall, livingroom (for ministicks!). More flexible that way.

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Old Feb 27, 2008, 09:12 PM
B for Bruce
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The 'Wack, BC, Canada
Joined Oct 2002
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I never understood the shift to the kinked wing posts. "Back in my day" we just made one wing longer than the other to achieve the offset and used vertical posts.

Of course it looks a heck of a lot more mysterious but it sure makes it harder (and heavier of course ) to build. I just do not see any purpose to it at all other than the "Kool" factor.
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Old Feb 28, 2008, 03:54 AM
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Got wing tubes glued to stick, and wing mounts glued to wing. Getting the front and rear posts lined up was not easy, especially with the posts being bent. There seems to be a twist in the wing, which I'm having a bit of trouble removing. Have added some support gussets to help. Having done some hand tossess in living room, the plane wants to turn RIGHT. Tried reducing washin, in left wing, but it still turns right?? Although I do think the bent posts look cool, may build a second wing for this plane and just make one side 1/2" longer (mount center rib offside). Then I'll make straight posts and see if that makes it easier to get plane to turn the way it's suppose to.

The plane looks kinda nice with the rounded tips and all. Got the weight down to 3.6 g. Heavy by most standards but 2 g. less then my first attempt. Making some progress. Will see if I can't build the 2nd wing using smaller sized ribs and spars. That and the straight posts aught to save more weight. Am pretty sure lot of the weight comes from the tissue. Being somewhat thrifty, gotta use it up before moving on to a lighter covering.

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Old Feb 28, 2008, 12:46 PM
B for Bruce
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The 'Wack, BC, Canada
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I'm pretty sure you're right about the tissue being your biggest handicap at the moment.

I gather you have a scale available to you? Measure some tissue and figure out the weight/sq inch and then do the math to see how much the tissue on your model weighs.

Now (and here again I'm saying this to hopefully guide and encourage rather than dissillusion) consider that the previous version of the FAI indoor class models were 50 cm span and had to be built UP TO the 1 gram minimum weight for the airframe and covering. Even if you discount the covering altogether that means the wood in the model as well as the prop shaft and everything else was still only a gram or less. And the rule was only instituted because the previous open rule models were so light that it was extremely difficult to transport them to the sites from around the world. Before the weight rule FAI indoor models were 50 cm in span and were under a gram without the rubber. And before the 50 cm span rule they were up around a meter in span and typical weights were a gram and a half.

It's a whole other dimension with its own physics that you've stepped into....
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Old Feb 28, 2008, 02:28 PM
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Holden , Massachusettes
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If I didn't appreciate advice, would never have posted these builds. It takes a lot for me to get dissallusioned. Have picked up on almost all the advice, that's been given. May not apply it right away, but will remember it in future builds. Have found that to get the most out of things, an appreciation of some of it's history is worthwhile. So having used tissue and condenser paper, will all the more appreciate and understand the use of mylar, when I do get to it.

Seems as things get lighter and smaller the physics gets tougher to handle. There is one really great thing about these smaller planes, for the cost of 1 open class RC glider, I can make 15 or more indoor models, just gotta find a place to put em all. My RC gliders have already taken up half my computer room.

How did the 50cm planes fly in comparison to the smaller ones being made today? Might like to try making one that big. Don't know about the meter size, however, I can see how they might be hard to haul around.

erich
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Old Feb 28, 2008, 06:58 PM
B for Bruce
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The 'Wack, BC, Canada
Joined Oct 2002
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The world record at the time was up around the 70 to 80 minute mark if I recall. Now mind you the site and the internal "weather" makes a huge difference so times from one world championship event to the other varied. But it was very common to see winning times of from 55 to 65 minutes depending on the year and site.

Humbling, isn't it....
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Old Feb 28, 2008, 08:43 PM
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Heck, I've had planes up for over 2 hrs. And that's OUTSIDE. Kidding aside (although the 2 hrs. is true), that's pretty remarkable. Am surprised competitors went along with the smaller planes. But I can guess at some of the problems with planes getting bigger and bigger. Suppose there had to be a cap somewhere. Sometime gonna see if I can get plans for one of the bigger planes. Not for competition, just to see it fly. But for now, my mission is to get, Ron's ezb #3 to fly right, or at least to turn to the left.

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Old Feb 29, 2008, 03:28 AM
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Framed up for 2nd wing. Have sliced off a little thinner ribs this time. Closer to the .030 x .030 called for in Ron's book. First wing I went .030 x .050 (ribs). The dimensions are just to show differences between wings 1 and 2, they're not real accurate (use calipers to measure em). At this point in my building, 100% dimensional accuracy is probably not as impotent as relative size. Course I could be wong.

Before soaking spar, on advice, thinned out the area where curved tip section will fall. Soaked in hot water for abut 7 min.,then anchored one end, and pulled on spar slightly as it wound around curved form. Worked real well.

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Old Feb 29, 2008, 08:58 AM
Free Flight rubber flyer
South Carolina
Joined Mar 2005
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Quote:
Originally Posted by BMatthews
The world record at the time was up around the 70 to 80 minute mark if I recall. Now mind you the site and the internal "weather" makes a huge difference so times from one world championship event to the other varied. But it was very common to see winning times of from 55 to 65 minutes depending on the year and site.
Humbling, isn't it....
Ok, 70 to 80 minutes for a two flight total, but not a single flight. When FAI indoor was introduced, I believe it was unlimited, but a 1 meter span limit was quickly instituted. After a while (70's or 80's), a 65 cm span limit was introduced and the 1 g minimum weight added. Around 2000, the rules were completely revamped with the intention of limiting performance (particularly climb performance), so the span was limited to 55 cm and stab span and wing chord limitations were implemented. The minimum weight was raised to 1.2 g, and rubber motors were limited to .6 g, primarily in hopes of keeping the models out of the rafters of high sites. That last plan failed miserably because even when the 330 ft cargolifter dome was being used, models were able to make it all the way to the ceiling.

Now as for endurance figures, back when the 1 meter limitation was in place, people were reaching into the 40 minute range, but only in the mid 90's with the introduction of Tan II did people start pushing the hour mark. I think the best ever was Steve Brown's record, which was 56+ minutes. The reason you're thinking 70-80 minutes is because scores at the world champs are a two flight total.

The Unlimited class world record stands at 60:01 by Steve Brown back in 1996 with a 34" model weighing a little over 1 g. The US unlimited record was bumped up to 64 something recently by former world champ John Kagan with a plastic covered model of 39" span.


Quote:
Originally Posted by erich
How did the 50cm planes fly in comparison to the smaller ones being made today? Might like to try making one that big. Don't know about the meter size, however, I can see how they might be hard to haul around.
Old style FAI models were a pain in the rear. With the 55 cm limit and 1.2 g min weight, the models can be built fairly rigid. They use boron reinforcing on most of the components, so an average F1D would be as rigid as your new EZB, yet much lighter. These models are challenging to build, but are quite rugged for indoor models. The biggest issue is that they are heavily loaded down for torque. In low ceiling sites, they use variable pitch props, which are designed to load down the motor so as to limit climb performance in return for an extremely long cruise. In higher sites, the models are set up with lower pitch props and will climb out at a 40-50 degree angle, which is extremely steep for an indoor ship. The speeds attained during such a climb demand every bit of strength those frail structures can give.
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Old Feb 29, 2008, 10:18 AM
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Fascinating stuff. Must be quite a sight to see an indoor plane going up at a 50% angle. Sounds a little like a bungee launch. Got a sneaky suspicion this indoor FF stuff has the potential, for a LOT more involvment then RC soaring (my background).

For now am going to try and make a plane that will circle in the right direction and stay aloft for 2-3 minutes. Acheiving that, will put a smile on my face. Unfortunately gotta wait 2 more weeks before doing some flying. Will hopefully have a few more planes by then. In between making extra wings and getting this #3 to fly right, managed to put together an A6, from a kit. With the narrow wing, it looks real nice. Flies pretty good in my living room. Even circles to the left like it's suppose to. Weighs about 2 g. The condenser paper (which was used on the A6) is obviously quite a bit lighter than the tissue. And easier to apply.

erich
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