Author Topic: My MC 72 (Read 19275 times)

Duke.Johnson · « **Reply #50 on:** October 29, 2013, 10:39:02 AM »

Quote from: Tom Niebuhr on October 29, 2013, 10:26:50 AM

Duke Johnson said " I wish I could build that well. I have a Yates Dragon I'd like to build but I don't think I could do it justice."

My father used to say "If someone else can do it, I can too"

I have lived with that advise.

Don't sell yourself short. The best part of this forum is that so much knowledge is shared.

Thanks, I think I'm going to build a built up fuse and finish the best I can this winter to get ready for the Dragon. Now back to Robert's cool plane after this short message.

Randy Powell · « **Reply #51 on:** October 29, 2013, 11:10:53 AM »

I certainly see most of Robert's logic. But like everything else, you take logic and do experiments then decide if it is logic. If Robert has done his experiments and is happy, regardless of "the math", I say Rock On.

RC Storick · « **Reply #52 on:** October 29, 2013, 09:25:38 PM »

Quote from: Steve Helmick on October 28, 2013, 10:26:04 PM

Robert said that the photo was copied and saved as a .PDF file, nothing else, thus the question. Meanwhile, I'll look forward to seeing how close both the vertical and lateral CG's comes out. Oops, Spell Check wants to change "CG's" to "cogs". Damnit! Steve

I should have been more clear. The small red photo was doctored in PS with my numbers. The full size plane was brought into Adobe and a PDF was made from the plans at 150% of original size. Then traced on to white paper and center lines and wing locations were drawn. As I said before this will be as close to scale as one could get for a full blown stunt plane. Even the spinner is the right size.

I choose this airframe because I thought it would fall close to scale.

RC Storick · « **Reply #53 on:** October 29, 2013, 10:32:31 PM »

Quote from: Randy Powell on October 29, 2013, 11:10:53 AM

If Robert has done his experiments and is happy, regardless of "the math", I say Rock On.

There is hope

wwwarbird · « **Reply #54 on:** November 01, 2013, 06:45:18 PM »

Got that thing ready for primer yet?

RC Storick · « **Reply #55 on:** November 01, 2013, 08:33:32 PM »

Starting the wing tonight

RC Storick · « **Reply #56 on:** November 03, 2013, 01:11:56 PM »

Here is 2 shots of the wing. I should put the airframe together this weekend

RC Storick · « **Reply #57 on:** November 03, 2013, 05:11:46 PM »

Wing weight 3.1 ounces. I might have to add ballast say 10 ounces.

Dan Bregar · « **Reply #58 on:** November 03, 2013, 05:14:21 PM »

You do good work Robert, and lots of it !!!

Dan McEntee · « **Reply #59 on:** November 03, 2013, 09:57:40 PM »

Why not a I-beamer this time? And what wing are you using, looks like lost foam method?
Dan McEntee

wwwarbird · « **Reply #60 on:** November 03, 2013, 10:18:38 PM »

Are those laser cut ribs?

RC Storick · « **Reply #61 on:** November 03, 2013, 11:23:38 PM »

Its my design lost foam wing and no they are hand cut ribs

john e. holliday · « **Reply #62 on:** November 04, 2013, 08:57:30 AM »

Sparky you are an artist beyond compare.

RC Storick · « **Reply #63 on:** November 06, 2013, 05:32:04 PM »

Forth set of wing tips. These are molded and built up.

Howard Rush · « **Reply #64 on:** November 06, 2013, 06:01:28 PM »

That's very cool. I might have to try that on the new dog. Oughta take me a couple of months.

RC Storick · « **Reply #65 on:** November 06, 2013, 06:07:13 PM »

Quote from: Howard Rush on November 06, 2013, 06:01:28 PM

That's very cool. I might have to try that on the new dog. Oughta take me a couple of months.

I have 30 hours in tips and still don't have one done yet. The first 2 sets were too heavy and the third set was not well thought out. So this one was re thought and I started on them this morning. Lots of work! But I want a super cool MC 72. More scale like than any I have seen.

RC Storick · « **Reply #66 on:** November 06, 2013, 10:20:45 PM »

almost

wwwarbird · « **Reply #67 on:** November 06, 2013, 10:41:27 PM »

After studying the previous pic that shows the tip outline on the foam cradle, I was wondering how you were going to finish the wingtip outside of the last rib.

Looks like this plan will work, and it gives you some meat to work with for the leadout slot opening.

MarcusCordeiro · « **Reply #68 on:** November 07, 2013, 03:31:22 AM »

As always, very nice Robert.

Marcus

Doug Moon · « **Reply #69 on:** November 07, 2013, 07:16:39 AM »

Can you show the mold you used for the skin of the rib?

That looks cool.

RC Storick · « **Reply #70 on:** November 07, 2013, 07:28:03 AM »

Quote from: Doug Moon on November 07, 2013, 07:16:39 AM

Can you show the mold you used for the skin of the rib?

That looks cool.

No sorry. How it was done is I took a 6 inch section of the male plug. Cut it into a circle and sanded the tip shape into the foam. After I had 2 skins I sectioned it at the rib stations for the rib templates.

RC Storick · « **Reply #71 on:** November 07, 2013, 08:57:41 AM »

Well thie is how its going to look. So far 3 days into one tip. This is the best also the hardest thing I have ever done.

Duke.Johnson · « **Reply #72 on:** November 07, 2013, 09:00:29 AM »

It is looking great Robert. You're inspiring me to refine my building skills.

RC Storick · « **Reply #73 on:** November 07, 2013, 09:07:07 AM »

Thanks I'm really getting my stride back.

Duke.Johnson · « **Reply #74 on:** November 07, 2013, 09:12:04 AM »

I go through phases, sometimes I hit it hard and sometimes I can't get going. I've had the PT-19 on the kitchen table for a week and haven't touched it. The repairs are made and all I need to do is cover it.

wwwarbird · « **Reply #75 on:** November 07, 2013, 04:53:30 PM »

Probably a stupid question but I'm assuming you hollowed the tip block?

RC Storick · « **Reply #76 on:** November 07, 2013, 08:29:02 PM »

Yes it weighed 3 grams

Doug Moon · « **Reply #77 on:** November 08, 2013, 01:27:21 PM »

Quote from: Robert Storick on November 07, 2013, 07:28:03 AM

No sorry. How it was done is I took a 6 inch section of the male plug. Cut it into a circle and sanded the tip shape into the foam. After I had 2 skins I sectioned it at the rib stations for the rib templates.

That explains it well. I was wondering how you were gonna make the ribs.

That is a cool idea on how to make those tips.

They look great.

Thanks for the info.

wwwarbird · « **Reply #78 on:** November 08, 2013, 06:56:03 PM »

Quote from: Robert Storick on November 07, 2013, 07:28:03 AM

No sorry. How it was done is I took a 6 inch section of the male plug. Cut it into a circle and sanded the tip shape into the foam. After I had 2 skins I sectioned it at the rib stations for the rib templates.

And he says he's "just a mechanic".

Randy Powell · « **Reply #79 on:** November 09, 2013, 04:28:24 PM »

Yea, I'm in one of those spots right now. Can't seem to get going again. And with a plane near completion that's unusual.

RC Storick · « **Reply #80 on:** November 09, 2013, 06:57:56 PM »

Wing progress. Weight of this wing is 5.6 ounces including weight box, lead out adjuster and tips. With un sanded flaps its 7.25 no hinges or horns or BC.

wwwarbird · « **Reply #81 on:** November 09, 2013, 07:29:51 PM »

Looks good. Maybe I missed it, what's the wingspan and area?

This is first constant chord wing I've seen you do Sparky, it'll be interesting to see how you like it in the air.

Looks like you'll be painting next week!

RC Storick · « **Reply #82 on:** November 09, 2013, 07:38:13 PM »

56 WS. 9.75 cord 2.25 flap. Aprox area is 650.

wwwarbird · « **Reply #83 on:** November 10, 2013, 10:02:27 PM »

That's a real nice size Sparky. A big enough model that it could be a solid contender in competition, but yet not so big it's that it's overly difficult to transport. That's a perfect compromise for a lot of flyers.

"Heads-up" to all of you kit builders out there, hopefully you're watching and considering this one. Just don't forget the glow power option on the plans.

RC Storick · « **Reply #84 on:** November 11, 2013, 04:19:30 PM »

Well complete wing with flaps is 10.1 ounces. Is that light enough?

RC Storick · « **Reply #85 on:** November 11, 2013, 09:53:25 PM »

All sub assembly's complete. I should have it on its wheels this weekend.

Duke.Johnson · « **Reply #86 on:** November 11, 2013, 10:10:49 PM »

That fuse looks really nice!

RC Storick · « **Reply #87 on:** November 11, 2013, 11:15:40 PM »

Thanks it's scale. I was looking back and see that this plane is not 30 days old yet. I should have it all framed up in less than 30 days. The painting on the other hand will take some time. The oil tank behind the spinner will be gold leaf and it will be painted Miss Ashley Red with gold radiator's in all the scale places. It might have working stacks. I took my Mattel Vac-U-Form and made a pilot but I think I will do a detailed cockpit instead. I have seen some great work here and that has inspired me to do it. I also think I can do the details lighter than a pilot.

I am still thinking how I can hide my AMA number like I did on my Tbolt and still be legal. I'm sure it will come to me as I am painting.

wwwarbird · « **Reply #88 on:** November 11, 2013, 11:29:40 PM »

Cool stuff.

Just an idea for the AMA number...if you're going to do panel lines you could do the AMA number using the same thin black outline. It would be there, but it wouldn't really be noticeable until you got up very close to the model.

RC Storick · « **Reply #89 on:** November 13, 2013, 12:15:03 PM »

Well I am starting to fit everything together. Here is two shots of what it's going to look like. Airframe is 18.5 ounces.

I just ordered dope from Wicks. The gold paint for the radiators must have real gold in it. 28.00 per quart where clear and colors are only 15.00 so almost twice the cost. Thinner is 53.00. I have 3608 but I like to use the same thinners when painting. Less chance for problems.

MarcusCordeiro · « **Reply #90 on:** November 13, 2013, 02:29:53 PM »

Marcus

Douglas Ames · « **Reply #91 on:** November 13, 2013, 06:05:16 PM »

There's actually 3 CG's - Longitudinal, Lateral & Verticle.

Lateral CG (along the wing span) is more of a dynamic thing as half your line weight comes into play, plus the Cent. force applied to your tip weight. Above my head mathmatically...

I saw a picture of Al Rabe on SSW, hanging his model by the leadouts against a wall to check Verticle CG. If the wing is parallel with the wall, you got it!

Checking Long. CG is a given.

RC Storick · « **Reply #92 on:** November 13, 2013, 06:44:15 PM »

Quote from: Douglas Ames on November 13, 2013, 06:05:16 PM

There's actually 3 CG's - Longitudinal, Lateral & Vertical.

Someone has been listening!

Howard Rush · « **Reply #93 on:** November 13, 2013, 07:00:09 PM »

Quote from: Douglas Ames on November 13, 2013, 06:05:16 PM

There's actually 3 CG's - Longitudinal, Lateral & Verticle.

And they're in the same place. The classic way to find them (it) for a rigid body is to hang it separately by three different points. The CG will be at the intersection of the three lines that go straight down from the places it's hung from. Play the cartoon, "Where is this guy's centre of gravity?" at http://www.s-cool.co.uk/a-level/physics/moments-couples-and-equilibrium/revise-it/centre-of-gravity-and-centre-of-mass .

RC Storick · « **Reply #94 on:** November 13, 2013, 07:06:32 PM »

Is he being slung around on a wire?

Howard Rush · « **Reply #95 on:** November 13, 2013, 07:14:09 PM »

Quote from: Douglas Ames on November 13, 2013, 06:05:16 PM

Lateral CG[/b] (along the wing span) is more of a dynamic thing as half your line weight comes into play.

That one again. See post 17 of http://www.clstunt.com/htdocs/dc/dcboard.php?az=show_topic&forum=103&topic_id=382606&mesg_id=382606&listing_type=search#382738 .

Howard Rush · « **Reply #96 on:** November 13, 2013, 07:41:09 PM »

Quote from: Robert Storick on November 13, 2013, 07:06:32 PM

Is he being slung around on a wire?

That is actually a good point, as we discussed elsewhere. Lots of us take for granted that gravity is an acceleration and so is what the wire by which an airplane is slung does. It wasn't (the details weren't anyhow) obvious to people before Newton figured it out. I looked a little on the Web for a good explanation, but didn't find one. I probably saw it justified somewhere long ago, but I don't remember the justification. Serge explained this for a living, so he can probably explain it rigorously enough to satisfy the skeptical student. It works, though, and we use it to design airplanes and inertial navigation systems, and Brett uses it to steer satellites.

Douglas Ames · « **Reply #97 on:** November 13, 2013, 10:37:15 PM »

Quote from: Howard Rush on November 13, 2013, 07:00:09 PM

And they're in the same place. The classic way to find them (it) for a rigid body is to hang it separately by three different points. The CG will be at the intersection of the three lines that go straight down from the places it's hung from. Play the cartoon, "Where is this guy's centre of gravity?" at http://www.s-cool.co.uk/a-level/physics/moments-couples-and-equilibrium/revise-it/centre-of-gravity-and-centre-of-mass .

Agreed.
I was thinking of a "3D ball" that represents the CG with 3 lines running through it - Vert./ Lat. / Long. ...and it moves.
Your chart is interesting but trimming wings level with a buddie/spotter outside the circle is a quicker solution.

Steve Helmick · « **Reply #98 on:** November 13, 2013, 11:18:19 PM »

Quote from: Trostle on October 29, 2013, 01:02:35 AM

Very Interesting

KT

Not so interesting. At the time, we were then looking at Robert's 2-view drawing, so vertical was up/down, lateral was left/right. Had nothing to do with airframes or aeronautics at that point. In a 3-D situation, it's different, of course.

I'm mostly interested in where the fore/aft CG will be, before trimming commences...and after. It's got to be correct, not close enough. Secondarily, is the constant chord wing going to be a deal killer in turbulent conditions?

Steve

RC Storick · « **Reply #99 on:** November 13, 2013, 11:21:39 PM »

Quote from: Steve Helmick on November 13, 2013, 11:18:19 PM

Secondarily, is the constant chord wing going to be a deal killer in turbulent conditions? Steve

I bet it will be fine.