Ragwing

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Hey guys, thought you might like to see some photos of what I've been working on for the contest. I just got a roll of film back from the developer today.

For those of you who haven't gone to the contest site, I'm building a 1" to 18" scale Lockheed Altair. Wingspan is 28", and I'll be powering it with a Cox TD .020 on a backplate with a remote tank, two channel control with Aileron and Elevator. The real plane was fairly quick, for its time anyway, and I hope mine will mimic that trait. This is my first scratch built plane, its all balsa; I plan on vacuum forming my own cowl and cockpit.

I've included a shot of the real plane, and a side view drawing to give you a better idea for the fuselage will flesh out. Instead of drawing the structure onto the 3-view I drew up my own plans for the wings, and tail group. A photo of the wing plans are shown, as well as the completed wing (at least until I install the servo). Sheeting is 1/32" balsa and is on the upper half only.

Ragwing

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The fuselage is a former and stringer construction. I had to make 9 formers; I cut the notches into them using the template shown in the first photo. This gave me a pretty good starting point, but it wasn't perfect, I'd be interested to know how other people go about that part of the design.

The fuse is built in the Guillows style, I can hardly wait to put the stringers on but I need to first get all the internal stuff set up, there won't be much finger room for that sort of thing later.

The final shot shows the completed rudder, I have since then also completed the horizontal stab, and a TD .020 is tossed in for scale. I'll be using balsa blocks to make the fillets around the stab and rudder, and then removing as much un-necessary material as I can to lighten them up.

I am working on a bubble-less eye dropper tank that I would like to run with the TD, just to get rid of the vent line. But I haven't tried one out yet, I'll work on that when I break in the engine. I plan on using a Ziploc bag that I will form using a food sealing device that I picked up at the thrift store for $1.50. I made a bag and put some 15% in it last week and so far it is still holding-no leaks, now I need to try 25%.

It's been fun to watch it coming together, little by little. Thanks for any input on the project!

Derek

ajcoholic

My Feedback: (10)

looking good... do you know what you will cover the fuse with? Sheet it or open stringers and just cover?

AJC

Ragwing

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Right now I'm planning on just leaving the stringers open, but I hadn't given it much thought. I've been building this plane like I would a guillows kit because when it comes down to it, Guillow's kits are the only scale ones I've done. So I guess I just don't know any better. How would I go about sheeting somthing like this? 1/32 over the stringers or planking? Thanks AJ

Derek

lipice_man

Hi there -
I always sheet the fuses I build up with stringers, on the cylindrical/semi-cylindrical fuselage it makes it super rigid, even if you use the thinnist stock you can find. Very nice if you wanna add strength without toooo much weight... but im sure you already knew this

combatpigg

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HI RAGWING! That's very nice work you're showing there! To answer your question about placing stringers on bulkheads, once the bulkhead gets real tiny, I don't notch in, I just lay them on the surface, and come back later with chunks of filler to lock the stringers to the bulkheads, again if there's enough room, otherwise mounting them on the surface, with no notching in will look just fine under the covering, and be plenty strong for any of the 1/2As I go out with!

Ragwing

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Thanks for the advice guys, I've got some cogitate'n to do.

Derek

Ragwing

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Here are some more Photos.

I did quite a bit of work on this project during spring break, which ended last week. The photos show the first things I completed, the elevator servo installation and the stringers on the fuse. I basically ended up using CP's method for adding stringers, which meant I had to go back and fill in many of the notches I had cut.

Since the time I when I took these photos I have added the wing fillets, turned a cowl plug and formed a cowling, and built a vacuum forming box, made a canopy plug and I have formed some prototype canopies.

My class load is really heavy this quarter, the late nights started the first day and show no sign of letting up. So it will be a struggle to fly this thing by the deadline, but I won't give up now. Physics lab got out early this morning, so I'm going to try and fire up the TD before mounting it on the firewall.

I'll try and get a lot done on the airplane so I can finish up another roll of film and upload more pictures for all of you.

Derek

Ragwing

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The TD Screams!

Well since I last posted, I have been trying to get the TD running. Nothing worked, I even made a new gasket for the crankcase, but nothing. Then about 15 minutes ago I tightened the head, and ziiiippp! it took off on the next flip.

Furthermore, my 1/2 oz Bubble-less fuel tanks set up works perfectly. I was able to move the tank all around with relation to the engine and it made no difference, whats more, it used up ALL the full in the bag--nothing left. I really wanted to avoid the multiple lines for vents and clunks, and this works perfectly, one line, no clunk or vent line.

Well I've had my fun, time to go to work []

Derek

Ragwing

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Well the Altair is finished! ....or at least it was [:@]

After completing the covering and trim job, and installing all the gear I decided to take the plane out for photos and some test glides. The good news is that I have some really nice photos of the plane to get developed, and I know it will fly! The bad news is that after a few dorked tosses I'm going to have to make some repairs.

My first toss was overhanded, and it really went poorly, the plane spiraled into the ground. I decided to try underhanded instead and it worked a whole lot better. I think I did two more tosses after that, and it really did glide pretty well.

The repairs won't be major, the only things that broke were a piece of wood in one of the wingtips and a cowl mounting block. Plus the cowling has a crack in it. So tonight I will glass a small area around the outer edge of the cowling to fix the crack and prevent new ones. Along with tearing into the wingtip to fix it, and repairing the block.

I'm glad I did all this tonight instead of on Friday, I just hope it doesn't get too windy (the forecast isn't good).

In any case, I'm glad I have pictures of the plane while it was pristine (or as "pristine" as she is going to get).

Derek

BMatthews

Sorry to hear about the damage. But I know you'll get it fixed and out again. Small models like this really can't be test glided very well in my experience. It's different if it's a 2 or 3 oz rubber model but with radio and an engine I bet you're closer to 10 oz and that spells trouble with a capital T and that rhymes with....

Sorry....

Anyway I think you're best off to just start it with a minimum of fuel and toss it. Get someone to do the launching honors so you can correct any initial trim problems. And start with a CG closer to 25 to 27% and work it back from there based on how it likes to come back to level in the dives.

combatpigg

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HI RAGWING! If you take the plane and hold it at arms length, really survey the wing from the rear, scanning from side to side and looking for a warp. You can also block the plane up on a table level, and take measurements off the table to various points on the wing to check for straightness. Have you also checked the LATERAL CG? [I usually forget to]

ajcoholic

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I allways test glide my 1/2A models, but usually over some nice soft SNOW - its a little more difficult in the spring and summer months...

Looking forward to the pics, and hopefully you will get a decent test flight!

AJC

Ragwing

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Hot Dang IT FLYS!!!!!

I glassed the cowl last night, along with the mounting blocks, and fixed the wing, so when I woke up this morning to dead calm air I just had to give powered flight a shot. Fortunately my dad was able to come along and take some pictures, which I will have developed this morning, and get uploaded tonight.

The flight went flawlessly, I couldn't have asked for a better maiden flight. The TD started up quickly and maintained a solid run until the fuel was gone-the bubble less tank works perfectly, upright and inverted. I did an underhanded launch, and with a couple of clicks of down elevator trim the plane was stable. The plane flies really nice, and fast too! It looks really good in the air. Funny thing, when the engine quit it suddenly became very squirrelly. I don't know why, it was probably pilot induced .

BMatthews and Combatpigg, thanks for the advice. With at 370mah NIMH battery in the nose, the balance is right about 25% of the root chord. But just to be safe I added a little bit of lead shot to the nose this morning. All up weight is 9.5 oz, heavier than I wanted, but it really does fly well. Thanks for the advice and encouragement.

Photos tonight!

Derek

ajcoholic

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Congratulations!... no better feeling than a good test flight!

AJC

combatpigg

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Nice going RAGWING! I think the power off sensitivity could be from nose heavyness? If you have to hold lots of up elevator to get it to glide decently, the airbrake effect could be bringing you close to a stall. Small models with tiny reynolds # have very definite GO/NO GO weight limits, and with out the prop blast, the plane is probably treading on thin ice in the glide, which will make the CG critical.

Ragwing

My Feedback: (2)

Thanks guys--AJC is spot on.

Combatpigg, I think you're right about the nose heaviness, that is the way it was behaving. This morning I didn't think I was adding much weight when I put the shot in the nose, but I took it out and weighed a few minutes ago and it was 1oz! So that should make a pretty big difference next time. I'll just have to be ready to give it some nose down.

PS I found a really cool way to add weight. Using the bag sealer that I used to make my fuel tank I made a little sealed envelope containing the shot. It’s clean and elegant.

Also of note, I found a really clean way of making pushrod ends when using Sullivan golden cable. I put z bends on a really short piece of wire, then I C/A'd a half centimeter of the wire to the end of the cable. I then encapsulated that in heat shrink tubing. Its strong (at least it will withstand far more stress than the aileron or elevator links on this plane will ever see), and its elegant.

Did I mention I like elegant?

Derek

BMatthews

Ragwing. On your next outing try trimming it for level hands off. Once trimmed dive it at a 30 degree angle and release the sticks. It should pull up only very slowly. From 30 nose down to level should take about 70 to 80 feet or more. If it's less it means you have your balance point too far forward and are using too much up trim to compensate for level flight. Basically you want to keep edging the balance back in small increments until the dive test almost does not pull out. It should just have a nice slow tendency to nose upwards. You, of course, will step in before disaster strikes...

Ragwing

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I just finished scanning in my pictures so here it goes:

Ragwing

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Sorry, it seems that RCU is reformatting the photos when you click on them, which adds a bit of distortion

My real in flight photo is rather unimpressive, we were using a 50mm lens, and the plane is quite quick-oh well. If you turn your head just right and squint a little.....

matchlessaero

WOW! Ragwing, that really is beautiful. Great choice for a contest plane, and a wonderful building/finishing job.

I really wish we could get all these entries together in a shot together. Would truly be a gathering of some of the prettiest, best engineered 'small' airplanes around.

Ragwing

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Ok, I had to yak just a little bit more about this fuel tank.

Basically it is just an eye dropper bottle with the top cut off and a small (1/16 inch) hole has been drilled in the end of the bottle for a vent. I made the bag out of a Ziploc, measured so that when formed it would nearly fit around the outside of the tank, and then sealed it using a food sealer that I picked up at the Salvation Army Thrift Store, for $3 bucks. I've cut a small piece of brass tubing and fitted the fuel tubing around it. Then I gathered the bag together around the tubing and cinched it down with a zip-tie. The cover is the finger of a glove with a whole cut in the tip. It's not really necessary, but it does keep the bag in place.

So far, I have been very impressed with it. I have run several tanks through the TD on the bench with it and I can move the tank anywhere in relation to the engine and I didn't notice an RPM drop. It is light weight, and so far, durable. I built this tank about a month ago and it has had 25% residue in it ever since and so far no degradation of the bag. Granted, I do make sure the tank is empty and inflated after I have used it.

We'll see how it holds up, but if it continues to work this well I don't see why I'd ever go back to a clunk tank. They are heavier and must have two lines minimum. This is much more elegant .

Derek

ajcoholic

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Very, VERY nice looking plane... Looks gorgeous!

AJC

Ragwing

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Thanks for the compliments guys!

I went to fly the Altair today and found that my "perfect" fuel tank was leaking-so now I'm eating crow. [:@] Upon inspection I think it was the operators fault, with the fuel tank inside the plane I have no way of telling when it is full, so I think I over pressurized it and popped the seam. Next one will have a bag that is too big for the tank to avoid this problem. In the mean time I have some cleaning up to do.

I've uploaded a video of some of my photos with commenatry and I'd reccomend that you take a look at it.

Derek

combatpigg

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HI DEREK, Would a little party balloon fit? They generally never leak, but they should be changed periodically