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Old Jan 01, 2005, 10:24 PM
Gravity is a harsh mistress.
Tim Wolff's Avatar
United States, MI, Temperance
Joined Sep 2002
6,605 Posts
Quick update. Forward cowl is laid out. The top sheeting is drying on the form, so I have time to post a couple pics. Spent more time thinking and tinkering than it actually took to frame it up. The cowl bottom and cheeks are kit parts. The top of the hatch will be sheeted. I don't think the whole front will come off with the hatch once I get it finished up. The fuse is going to make the wing look like a walk in the park.
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Old Jan 03, 2005, 10:29 PM
Gravity is a harsh mistress.
Tim Wolff's Avatar
United States, MI, Temperance
Joined Sep 2002
6,605 Posts
Seems the fuse is hanging everyone up

I'm willing to bet that I'm done with the most difficult part of this build...the hatch!! The sheeting wanted to twist the little hatch way out of wack. Glued it to the top "spine" first then to the front former, then the back. Had to hold it in an untwisted position while the glue dried. Finally the sides with it taped in place while the glue dried. I should have chucked the balsa I had formed. It felt like it had an uneven hardness that caused it to twist the structure.

Getting it on over the power system was another issue. I was mistaken when I said that the whole front would not be removable. It had to be if I wanted to make the motor servicable. The prop will have to come off in order to remove the hatch. It has a nice press fit like any rubber powered model should. I don't think magents will be needed. It's porker too!! Fuse weighs 4 grams now.
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Old Jan 03, 2005, 10:41 PM
Team 30 Micro EDF
Mike Taylor's Avatar
Camarillo, California
Joined Apr 2002
4,516 Posts
Tim,

I've been hung up with a sick wife and kids, so I have been super grandpa for a few days. I'm right behind you if I can get a little free time.

It look like you can shave a bunch more after shaping the from the inside of the nose block. You're not going to need that much balsa right up front; if you hit a wall the motor will take the impact, not the cowling...

Is that hot glue holding the Kenway down? I like that stuff because it allows readjusting the thrust lines very easily - as long as you can get to it all! I was thinking of mounting mine back a little further so just the cone on the output shaft would show through.

I've been looking at the LG. There is something that bothers me there. If the wire is attached to the balsa legs, I really think the bottom of the fuselage is in danger of getting munched on landings. I think I will make the LG fit UNDER the LG leg and not glue it down so that it can flex backwards without crushing the bottom stringers... Thoughts?
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Old Jan 03, 2005, 11:12 PM
Gravity is a harsh mistress.
Tim Wolff's Avatar
United States, MI, Temperance
Joined Sep 2002
6,605 Posts
I know the sick family thing too! Mine sleep alot when they are sick. But, I'm usually sick along with them

Let's not speak of hitting walls. My gut tells me that this is one of those airplanes that will only crash once. Lots of shaping to do up front yet. The pic that shows the gear is w/o the last block in place. The last pic shows the hole for the cone of the propshaft. The Kenway is/will be fixed with hot glue as is the prop. I can hollow out a bit from the backside if I'm nose-heavy (yeah..right!).

The landing gear fairing right? Gluing the fairing to the bottom of the fuse and placing it over the landing gear wire leg, but not glued to the leg? Right? Sounds like a fine plan. How heavy should the wire be? Too light and the fairings might touch the ground and shear off. The plan shows 1/32". I'll have to see how much bend it has at that length. I've got longer 1/32" gear on a Liddle Bug. Too much deflection for the Baby Ace, but fine for what it is on.

Do you think std. actuators or the larger Selman design would be best? I've got both in-stock. I think using the Falcon servos would slow things down alot as I would want to use pull-pull linkages and I've never had the Falcons in an airframe. I'm also considering a single cell battery. Two 210 mAh cells feel real heavy in there. Actually, it feels dangerously heavy with the motor and batteries in it. I suppose I'll know more once I get a feel for the finished airframe weight.

Investing in Esaki tissue worth the cost and trouble over the kit tissue? I've done a total of 2 models in tissue. Both with Peck kit tissue. One was over 25 years ago. As of right now, I'm content to let my micro modeling head in this direction as I've had my fill of single stick and profile fueslages. Sam's sells the Esaki assortment and those wire wheels (that's another project) and indoor balsa and.....
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Old Jan 04, 2005, 12:53 AM
Registered User
Arlington, TX
Joined Dec 2002
607 Posts
Weight

My .02? I know, unsolicited... Keep the weight down. Instead of using 2 batteries, use 1/2 battery. Order a 90ma cell from bsd. Do not streinthen anything. The strategy is two fold. First, Build a light plane that flies, instead of crashing. Second, a light plane has no energy. The plane will always hit the spot that you did not add streingth (weight) to. The Bristol racer Im building is my fourth model in this class. Here are some pics of my learning attempts. Their ability to fly is directly related to light wing loading.

18 inch buzzard F4 at around 50gm

16 in hurricane night fighter at 25 gm (cat fighter?)

13 in Prest baby pursuit at 23 gm

Two of my cats. I have not weighed them.
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Old Jan 04, 2005, 01:01 AM
Team 30 Micro EDF
Mike Taylor's Avatar
Camarillo, California
Joined Apr 2002
4,516 Posts
Crash worthiness - that is an interesting thing. Lighter models seem to do better in crashes than ones built to crash. There is less weight, and a light plane can't get up the momentum to do itself much damage.

I'll do a little more sanding and post pix of mine fuselage and hatch arrangement tomorrow. BTW, that was what I was talking about with the LG - letting the gear deflect without being glued to the balsa leg.

I'd forget about the 210 cells, especially if you want to carry 2 of them - that's 12 grams right there - almost half an ounce. You'd get real tired of flying before you ran them down (I got 18 to 22 minutes in a HF Lightning with RFFS and KP-00 with one 210 in it) and they are ~6 grams each. The 170's are a better deal at slightly more than half the weight (~3.6 grams) with the potential for 10 to 14 minute flights. I've been having fun with 2 x 135 and 2 x 170 packs driving N-20s, and I will most likely go that route for a 'sportier' model. Of course, that means that I will be upping the weight by another 1/4 ounce (3 grams for the extra battery and 4 grams for the N-20 over the M-20). Of course with the extra weight and power, maybe it will do loops...

As far as the actuators, I think I would go with the bigger ones unless you expect real sedate flying and are looking at ultra light weight. I think the 'mini's get kind of soft feeling at any speed while the BSD 'standards' continue to feel nice and tight even at pretty high speeds. Since it looks like you have an M-20 in there and are talking about maybe using 1 cell, the mini would be fine for the rudder and save a gram, but maybe you'd want to use a standard for the elevator (that's a lot of elevator for a single minimag actuator unless you made it balanced).

I think I will use the Falcons and run CF pushrods like I usually do. I just threw my fuselage and nose block on a food scale and it read 4 grams (+/- 1 gram); that's not too bad. I think I will use the kit tissue; no reason not to. There aren't any serious or compound curved areas to worry about and this is supposed to be fun... I think you get some good results with what is in the kit, but try some different tissues. Real Japanese tissue is a pleasure to work with. Check out the covering discussions and resources over at SFA... An interesting tissue supplier is JCI (http://www.jcimodels.com/index.htm) who sell pre-chalked Jap tissue...
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Old Jan 04, 2005, 08:28 AM
in persuit of low wing loading
Gordon Johnson's Avatar
Boston, Mass
Joined May 2001
6,438 Posts
You guys are making nice progress. I'm still using a knife to separate and punch out all the little triangles and rectangles in Oliver's superb laser cutting. The wing ribs scare me since they are the only part of the main structure made from balsa, and have lots of little pieces to punch out.

Gordon
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Old Jan 04, 2005, 10:30 AM
Team 30 Micro EDF
Mike Taylor's Avatar
Camarillo, California
Joined Apr 2002
4,516 Posts
Gordon - How about some pictures as you go? And speaking of pictures, I just got your Christmas card yesterday - great looking kids you've got there. The boys look really proud of Hannah... My granddaughter was hoping they were more of her cousins she hadn't met yet!

RocketMan - how are you coming on the Bristol? Any news?

FFLover - how the Buckner coming along

Enrico, Planophore - I haven't heard from you guys in a while. What's happening with your projects?

Did I miss any one? Love to see what you are doing!
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Last edited by Mike Taylor; Jan 04, 2005 at 10:39 AM.
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Old Jan 04, 2005, 11:19 AM
in persuit of low wing loading
Gordon Johnson's Avatar
Boston, Mass
Joined May 2001
6,438 Posts
Mike,
I plan to start a page on my progress on the Stampe on my web site, and put a link to it here when I do. Not much to take pictures of yet other than the progress punching out pieces.

Gordon
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Old Jan 04, 2005, 08:47 PM
Gravity is a harsh mistress.
Tim Wolff's Avatar
United States, MI, Temperance
Joined Sep 2002
6,605 Posts
Why is the equipment selection never easy....

The Kenway setup is an N-20. The data on the setup from EFlightDesigns shows 16.3 to 23.1 grams of thrust up to 4.2v. No data for 2 cells?? I've got 2 cell N-20s handy if the two are actually different. I have run this setup on one cell in a micro taxi and was not really impressed with the power. But, the Baby Ace should not be a screamer and it is swinging a 12 cm prop. A single cell setup saves the weight of the 2 cell addon board too. Falcon servos save about 1.2g over Selman actuators.

I'm not opposed to buying a pair of smaller than 210 mAh cells if they will make the project. I guess I should see how much weight I need up front and use a suitable battery pack. A 2 cell 90 mAh sounds nice and light, but I don't think they can be drawn that hard.

Thinking more about the gear...Spreading of the gear will mess with the fairing too. Maybe I'll leave the fairing off or use two gear legs per side so there is little or no rearward deflection. Could be hard on the fuse too???

I'm anxious to see what the rest of you are up to too!!!

I've got a wing to build and an 84 inch Quaker SAM old timer kit that has to be done for spring. .40 size Telemaster on an AXI 2140 in the queue too. Maybe my wife will let me quit my job?

I welcome everyone's suggestions on this project Rocketman. You've got 3 more micro scale planes under your belt than I do!! I've got to get everything frammed and see where I'm at. I'll have to worry about AUW then. It needs to be light, but it also has to be strong enough to land with the extra gear onboard. That's kind of where I was headed with the "only crash once" comment. I hope I'm wrong. I know my fuse is using "husky" wood up front. I prefer that or a bigger battery pack over clay though. I'm just guessing. It wouldn't be fun w/o some WAGs!!

I'll settle for a pic of the parts for now Gordon...
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Old Jan 04, 2005, 10:41 PM
Team 30 Micro EDF
Mike Taylor's Avatar
Camarillo, California
Joined Apr 2002
4,516 Posts
Quote:
Why is the equipment selection never easy...
Yes, it was easier when all there was available was the RFFS and the simple surface mounted actuators, the 145s and the KP-00

One thing I have found is that the GWS 5x3 seems to be a better prop than the blue 12 cm prop - that one was designed for rubber power and much lower rpm. The 5x3 seems to have less torque to over come as well.

If you have the JMP and Falcons, go with that and a single cell. If it needs more poop, add the 20cell board and another cell. The 170s are pretty well suited to this motor and 2 of them weigh about the same as a single 210.

Now for the fun WAGs: I just weighed all the bones and they are about 10 grams. Double that figure for tissue, dope wheels and wire, bits and pieces. Motor and prop (~7 grams), radio (~2 1/2 grams), 2 Falcons (3.4 gr) and 170 LiPoly (3.6). That's about 37 grams target weight. The single cell & N-20 w/5x3 produces a published 18 grams thrust, or about half the model's AUW and above the minimum thrust. That should be good for cruising around, ROGs should be possible and it should fly pretty well with a wing loading of 3 1/2 ounces per foot. If you need more sporty performance, add the 2nd cell, the add-on board and you're at 41 grams with 28 grams thrust; that's approaching the 'performance' range. Vm goes from 9.4 mph to 10 mph. Either combo should be fine for most indoor venues. Check some scenarios using Larry Park's Flight calculator on his 'tech resources' page (http://www.smarttoolsinc.com/)
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Old Jan 07, 2005, 09:04 AM
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FFlover's Avatar
Vienna, Austria
Joined Jul 2004
136 Posts
During the christmas holidays I was not able to make much progress on my Jungmeister as I`m having trouble finding light balsa(4-6lbs) and my stock is depleted.I have the ribs cut out for the lower wing and will probably put it together over the weekend.
I`ll probably have to add wood to the triangular sideframe as it looks way too straight.I drew the triangles up with the help of a crossection sketch of the plan but it doesn`t look right when I compared it to some pics and a three view.
Peanut model used 1/16 stringer on top of the sideframe and so did I(by accident),don`t know if I`ll correct it though.
What wingloadings are you guys looking at?

Dennis
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Old Jan 07, 2005, 01:57 PM
Gravity is a harsh mistress.
Tim Wolff's Avatar
United States, MI, Temperance
Joined Sep 2002
6,605 Posts
Check Mike's post above for a WAG on the wingloading.

Got the ribs cut, slotted, and sanded. Fiddling with the layout and actual construction of the wing.

You have convinced me to go with the Falcons Mike I'd have to rob an actuator combo from a flying plane to do actuators anyway. I fear that I'll never want to use actuators after I taste the Falcons

I've got another indoor session tonight, so there's no progress until tomrrow...
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Old Jan 07, 2005, 10:32 PM
Registered User
Arlington, TX
Joined Dec 2002
607 Posts
Bristol...

Starting to look like it might add up to a plane. No weights as of yet, but I got a nice set of undercambered wings, and the fuse has a M20 drive in it.

I was planneng to use the 12 cm prop that BSD issued with this drive, but I think I will follow Mike's advice and try the GWS 5-3.

I am now beginning to regret that I chose a plane that only had one color scheme. Silver dope. kinda boring... Oh well, I am contemplating a albetross D-V like the one in Mikes avitar. Hmmm, Earl Stahl 17.5 plan reduced to 13 inches, with losenge... I might even try rubber powered RC!

Walter

Oh yea, the wing had to be wet covered for the compound curve. I love tissue. The elevator hinging is over/under thread. Very precice and low friction.
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Old Jan 07, 2005, 11:19 PM
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Pete P.'s Avatar
South of Boston
Joined Mar 2004
846 Posts
Yeah, he does have a nice avatar :-)
On another note, have you thought about trying a 7mm SS motor rather than the m20? They have the same W/g ratio but are a bit lighter and a tad more effecient. Somebody needs to get some research done with those gears and props for some nice matches, however :-)
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Last edited by Pete P.; Jan 07, 2005 at 11:23 PM.
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