Okay... now that it worked...

Does anyone have an idea as to why some DC-3's/C-47's left off the tail cone (as shown in the attached phots from my test post)? What is proper military set-up? Common sense would say that the military versions left it off for weight considerations, but I am curious as to the actual reason.

Incidentally, this plane is on display at the EAA world headquarters in my home town of Oshkosh, WI. I have a ton of pictures of this plane; if anyone needs a close-up shot of anything in particular, let me know. If I do not have one, I'll go take one from the angle you desire.

Mark

could the tailcone be off for the tow hook installation.?

That would make sense. Last weekend I bought a pair of OS.40fs 4-strokes to use on mine. They're a much better fit than the saito .56's I was planning on. They were even used in a twin and have equal time on them. I will use the 1/4" steel rod jig I made awhile back. I've never done the root/tip sand the blanks method before so it should be interesting. As for the flattened fuse sides, I'll figure out some way to deal with that. Either flatten the formers a bit before build up, or modify the formers before I make the templates. Osman, how did you do the nacells? As someone earlier stated, I dont see any formers other than the firewall. Is it the TAR method (Thats About Right).
Edwin

I own a couple of 40 4 strokes surpass
I find that they have the power of a 25 fp in my Morris PenKnife ( had the 25 in it before ) will use a 52 next, but plane getting kind of tired,over 200 flights and 4-5 ho sh... moments )
not quite enough power but I love the sound

Mark:

All C-47s and DC-3s left the factory with the tailcone fairing. Over time, some were removed and not replaced.

If you are modelling a generic aircraft, include the tailcone. If you are modelling an actual aircraft, do exactly what your documentation illustrates.

David

p.s. I was given a tour over at Basler Turbo last winter as I was preparing to start my build.

that is a really neat place... I've never toured it, but reading on their website is quite interesting. Not to mention seeing all of those DC-3's in their backyard is pretty neat, too!

Mark

I used both some calculations and the TAR method to come up with a reasonable shape for the nacelle.

I used the center of circular firewall as a reference for calculating the radius of the formers. On the plans they give you the side profile of the nacelle. A horizontal line thru the center of the firewall gives you the reference line. Decide how many formers do you want along this line. At every former location draw a perpendicular line from the reference line to the outline of the nacelle. The length of this perpendicular line is the radius for the specific former. Use this to draw a circle. Cut that in half and then shape the halves to fit the two sides. As you move back along the nacelle outline the formers will get smaller and each would have to be shaped for their specific locations.

Hope this makes a little sense.

Well it looks like you did a good job. I was affraid that was what I would have to do. Oh well, no big deal.
Edwin

Marko, Osman,
I just got a pm from another person that built the plane and he said the fuse formers were not accurate. Did ya'll have any problems in that area?
Edwin

I haven't gotten that far yet, still working on the tail feathers. What isn't accurate about them, and do you know how much of a pain it was to get them to work?

I'm finding that some of the individual pieces for the fin and rudder as shown on the plan aren't quite right, but I'm picky, too!

Wish I had a heated garage to work on this... it is 10:00AM and -11 degrees F!

Mark

To my understanding, the profile wasnt correct. At least thats the way I interpreted it. I'm guessing that you wouldnt have a smooth contour from front to tail. Maybe Osman can shed some light on it. The only way I can think of to check that would be to measure the formers on the plan and see if they match at the fuseloge profile location.
Edwin

The elevators and the rudder have trim tabs shown on them. Are these abolutely necessary, and what is the best way to mount them? I would imagine that epoxy wire into the trailing edges and into the trim tabs so you can bend them slightly, if necessary...

I recently received the set of Flying Models plans for this plane (similar size) and there is even less detail on these than the MAN plans. I think I will make the outer panel wing ribs using the sandwich method as described on the MAN plans. One question I have is the way they show the tip rib in relation to the root rib. Because the outer wing has a swept back leading edge but a straight trailing edge, shouldn't the trailing edge of the tip rib template be even with the trailing edge of the root rib template? I discussed this with a friend and his only thought was that it would be easier to bolt the stack of rib material together and hold them in place more securely. I can appreciate this, but wouldn't the airfoil be different if you did it the way the plans describe vs. if you kept the trailing edges even?

Mark

I thought about that a little. I am planning on using the plans as a reference. Establish a line on the outer panel, then place the root rib, the blanks, then the tip rib. I think you are right, but not having it in front of me at the moment I cant verify. The main thing is to get any washout (TE) and leading edges lined up too. I was going to leave the root rib out until ready to mate up to the wing center section so the angles come out correct. This project just got bumped down a little further due to a Waco. At this rate, I'll have to live to 150 to finish all the builds I want to do.
Edwin

Hi,
Sorry I have been away for a while.

I did have trouble with the contour due to the formers. If I remember correctly the last four or five formers (towards the tail) have to be reshaped to get the get the contouring right. The height of the formers is probably right, so they would match if measured with reference to their fuse locations on the crutch. The problem is actually with their individual contours which do not match up to give a smooth rounded curve of the fuse at the tail end. Viewed from the top the convex contour profile dips inward at these last few formers. I found this out when I started planking. The pic below will explain this better.

About the ribs, I converted my autocad file for the outer panel ribs to pdf. format. I think I cant attach this file to this forum as it gets scaled down. If you guys can give me an email address I can send it as an attachment. You can then study the file and see if it helps. My impression of the sandwich method wasnt all too great and I took the cad way to do the job. Worked out fine for me.

Osman

Thanks Osman.
Edwin

Do you remember what you did to remedy the situation as you were planking the fuse? I was thinking that I would inpart a gradual taper from the last correct former to the tail and just build-out the incorrect formers to fit, although I am not sure it this needs a more parabolic contour or if a straighter profile would be closer to scale.

Osman, I will PM you to get your rib .pdf file. I still am undecided as to whether I will do the sandwich method or if I will cut out each rib using somethng like your auto cad design.

I'm almost done with the armoire I am building for my wife, then I can devote even more time to this

Mark

Mark,
I would do what you said. As you terminate the stringers at the back, you can scab in some scrap wood to the wrong former and finish sand to the correct contour using the TLAR method. (That Looks About Right) If I run into that problem I'll correct my plans since I'm sure I'll build another one of these much later in retirement too. Also have to make templates for the additional nacell formers.
Edwin

That's just about what I did to correct the curve. Used stringers from the last correct former till the back and fill in the gaps for the incorrect formers with scrap balsa as Edwin suggested. I would not go for a straight line. A little gradual curve that progresses from the last correct former till the back would be more scale, although it is very close to a straight line.

Osman

Has anyone built the Top Flite DC-3.......82.5" kit? I've been eyeballing it for a little while now and would like hear a little about this particular kit.

This time last year I was knee deep in the 100" Eindecker E1 from SR Batteries. Great kit / plane, a real head turner at the field. I'd like to think that this DC-3 would be a real treat as well.

Try this thread for the Topflite DC-3
http://www.rcuniverse.com/forum/m_99.../tm.htm#999970

Im sure if you use the search box in the forum for the particular topic you can get more info in other threads.

Osman

Here's a site that's been very useful as I am building my C-47 conversion:

http://www.rcdon.com/html/ec-47n__dc-3__project.html

And here are three really good RCScaleBuilder threads. You have to register to access the RCSB forums but it is well worth it to get to these threads:

http://www.rcscalebuilder.com/forum/...s.asp?TID=5095 &PN=4&TPN=1

http://www.rcscalebuilder.com/forum/...s.asp?TID=162& amp;PN=1&TPN=1

http://www.rcscalebuilder.com/forum/...s.asp?TID=1382 &PN=5&TPN=1

That should get you started. These were the best sources for me as I did my TF DC-3 bash.

David

Thanks guys. I'll check them out.

Okay guys, it has been awhile. My camera's on the fritz, so a brief description of where I am at will have to do.

The fuse is to the point of where I could take it off of my jig I used to build it on. I am starting to think about where and how the control linkages for the rudder and elevator will be set-up in the tail. I've decided on using Goldenrods and keeping the servos towards the front of the plane. The rudder/fin turned out pretty good so far; the only place I varied from the plans is how I attached the micarta hinges to the rudder. I used a system similar to how they do it on the Top Flite DC-3. I used a 5/32" ID tube and inserted that in the rudder between each hinge point and through each rib in between the hinges. Next, I used a piece of 1/8" music wire and inserted it through the top of the fin, into the pivot point all the way through the bottom hinge to the last rib on the rudder. I CA'd a piece of 1/16" lite ply on top of this rib to deal with friction problems. I left the 1/8" rod sticking up about 1/16" from the top of the fin so I can remove it with some vise grips if necessary. The music wire fits quite snugly in the 5/32" tube, but still provides very little resistance for the rudder to pivot. I doubt that the rod will ever fall out, but if it gets loose, I can wedge it in the top of the fin somehow, as the rod doesn't need to move, it just needs to provide an axis for the tube inside the rudder to turn on. I will post pics as soon as I can.

One question I have, as I've had little experience with built-up stabs and fins that are contoured to scale. How do you line up the centerlines of the fin and stabs so they are perpendicular? Or is there supposed to be a slight dihedral in the stabs? (this I doubt). One thing I've thought of doing is measuring the degree of taper on both stabs and the fin, and adding these degrees to 90, and make a "square" specially for this situation. For example, if there was a 1 degree taper on the stab and a 1 degree taper to the fin, I would make a "square" that was actually 92 degrees. Is this plausible, or am I trying to reinvent the wheel by taking a round object, planing it down to 4 sides, only to sand the corners round again? Thanks for the help!

Mark

Hi Mark,

Been quite a while now since my last response. I'm just about done with the painting. Hopefully the test flight will be in a month or so.

I have used pull-pull cable system for the rudder and elevator controls, as I thought that the distance was a bit too much for nyrods with the servos upfront as mentioned on the plans. I used double linkaging for the tail-wheel and rudder connection. In hindsight though I should have taken separate pull-pull cables from the tail-wheel and the rudder to the common servo for both. Anyways hope this will work out too.

One thing I am worried about for now is the all up weight which is getting close to 14lbs (without the fuel). The wing loading is coming out to be around 36 oz/sq.ft. I will be using two ASP 0.52s with 11x6 props. Will have my fingers crossed on the test flight.


Osman

Hi!
How large is it? 7kg...?