OsmanKhan

More pics to invigorate you guys to go ahead with the project !

Osman

Edwin

My Feedback: (2)

Osman,
In your third picture you show a pull-pull system running to the tail section with what looks like a pull-pull heading to the nose. Whats that for? Anamated cockpit?
Edwin

OsmanKhan

Nothing of that sort, Edwin. There are two pull-pull systems. One for the Rudder and tail-wheel, and the other for the elevator.
Osman

OsmanKhan

Has anyone used the CLINE fuel regulation system for 2-strokers. If it is a tried and tested system, I would probably opt for this as opposed to putting a header/hopper tank to get reliability. Do you know of a thread in these forums where I can get more info on this. Thanks

Osman

Edwin

My Feedback: (2)

I only know hearsay and dont know anybody personally that has used one. But they say it works. I guess I would try it out on a beater plane first. I've also heard the header tank works too. There is a guy on rcu called twinman that has done it. I've met him a time or two at swapmeets to talk about this kind of stuff. If you post it, I'll bet he responds. He's done a lot of experiments with different fuel tank setups in multi-engine planes.
Edwin

OsmanKhan

Thanks Edwin. By the way, I am quite interested in your idea of dropping 10 paratroopers off the dc-3. When do you think the contraption will materialize as a working model. Would love to put that in my bird once it takes off.

Osman

Edwin

My Feedback: (2)

Will probably be a long while before it materializes. Its basically a spring about 18" long. The coils would need to have spacing between them, I figure about 3/4" or so. A gear reduced motor would turn the spring slowly. The paratroopers would have a hole on top that would be threaded onto the spring. You would load the paratroopers by running the spring in reverse. Then run it forward to eject them one at a time out the door. The spring would have to be mounted in a box with a slot in the bottom because the "output" end of the spring has to be free to release the paratroopers. I found a company that sells toy robotic gear drives that would work perfect for this. A light weight spring is the holdup. But now that I have a lathe I can probably make the spring to fit my purposes. Clear as mud? I'll see if I can draw a concept on my cad s/w. A picture is much better than words sometimes.

I have 4 projects to finish before thinking about the DC-3. The 4th is a proof of concept test plane for mechanisms like this. I'll call it the HerkyStick. Pretty much a big stick fashioned into a boxy C-130 about about 90" to 100" ws. I want to get some 4 engine experience.
Edwin

OsmanKhan

A cad drawing would really clear things up. Hope u can come up with one by the time I'm done pulling off the test flight which is a minimum couple of months away.

Osman

Edwin

My Feedback: (2)

Osman,
See if this explains it. Pretty basic, but should do the job. Here is a pointer to the company that sells the gear reduced motors.
http://www.pololu.com/products/gearbox.html
Edwin

OsmanKhan

Amazing simplicity Edwin!. This will be my project over this weekend. I will do the spring rotation manually to work out the timing of the drops and see how it works out.

One question about the release point. Would the release end of the box have to stick out of the cargo door, say an inch or so, to make the trooper drop in the air? i.e. how do u envisage the placement of the release point with reference to the exit point on the plane?

Osman

Edwin

My Feedback: (2)

I was thinking of some kind of chute. Once the paratrooper is disengaged, maybe it would slide down the chute and out. Havent really put too much thought in that part of it. Was thinking I might secure it with velcro on the cabin top so I could remove it to load the paratroopers. Another option (my 10watt light buld just turned on), A guide wire or tube could be used and have a plug on the spring to move the paratroopers down the guide wire. The guide wire could then be curved to go up to the door. Need to think on that one some more. Either way, thats the jist of it.
Edwin

marko509

I like the idea of the chute- it keeps things simple and would help propel the trooper down out of the way of the stab. Hopefully none of those troopers experience a "roman candle!" (when a chute fails to open or deploy properly) [X(]

Osman, keep those pics coming! It is still slow going, but seeing how yours turned out is inspiration indeed!

Mark

OsmanKhan

Mark have you thought about the wing ribs for the two outer panels?. The plan mentions the old method of sandwiching and shaping balsa pieces between the root and tip ribs to get the intermediate ones. I gave up on this method and went the CAD way of simply scaling down the ribs starting from the root. I didn't check with the actual literature and hoped that their is no transitional airfoil changes, i.e the root being one specific airfoil and the tip being some other. I assumed that it is ClarkY airfoil for all the ribs. Anyways with the present softwares you can do anything, even have the washout (I put in a 2degree for mine manually) built in into the rib design.

Osman

OsmanKhan

By the way Mark, don't worry about the failed trooper drops, we wont be using live ones in any case

Osman

Edwin

My Feedback: (2)

Ya know, In all this time I hadnt put in effort into how the parachute was going to stay bundled. Has someone already given that some thought? I was thinking maybe a pin to someplace somehow.
Edwin

marko509

There is a plan from Flying Models magazine that has a 96" wingspan. I've talked with a gentleman who built the Paris White fuse and fitted the FM wing to the fuse. I asked him if he had any problems with the increase in wingspan, and he said no. He said that it was a great model to fly. The FM plan shows each rib individually, which I would prefer. As far as using a CAD program to figure this out, I wouldn't know even remotely where to begin with this! The FM plan was $15.00, and $3.00 extra got you the November 1977 issue that featured the construction article, which I was told was excellent. Incidently, he built-in 2-1/2 degrees of washout into the outer panels. I agree that it would be more simple to design the wing and ribs with the washout already figured in, but as I said, I am not very well versed with CAD stuff (okay, I am not versed at all with it!)...

Mark

marko509

Just wondering about washout... from looking at the Paris White sheet that shows the two outer wing rib patterns, it almosts appears that there is some washout built-in by the way the smaller rib pattern is aligned with the larger rib pattern. Am I correct here?

Mark

OsmanKhan

Mark, why did the gentleman opt for the Paris White fuse instead of the one in FM? This is not to get you off the project but over the years that I have been at this scale project the Paris White fuse is one thing that has presented the most challange in getting it right. Building the crutch and putting half the formers on one side is pretty easy, but getting to make a jig and having it aligned to come up with a straight fuse is a bit awkward as far as construction technique is concerned. Do the FM plans have a different technique for the fuse construction?

Also one thing that I did find out later on when I got a 1/72 scale plastic kit for the DC-3 was that the fuse is a bit flattish on the sides, while the Paris fuse once planked presents a more rounded off fuse, like a cigar shape. Let me know if you agree with this by looking at the formers given in the plan and comparing it with some scale drawings of the plane. It does nag me a bit now that I have made the fuse to feel it is off scale a little bit. May be you can avoid this once you begin the project.

I will post a file for you next time for the wing construction that I used myself. It is an AutoCad file, but if you dont have it I can convert it into pdf format for printing out.

Osman

OsmanKhan

About the washout, since I did not go the way it says in the plans and as it does not say about it in the literature or on the plans, assuming there is a built in washout would be risky.

Osman

jaka

Hi!
Of course you should use wash-out !
I think most full size airplanes has was-out in their wings. Spitfire has, same with P-51 Mustang . DC-3 must have it too.

skypupmut

the DC/ does need washout, it can be snappy at slow speeds, jus release the elevator and it will get back to level flight
I like to have a little bigger engines , you need the weight,plus safer at takeokk I flew one Top flight with 2 46 fx engines, too much power for sure but it would fly great on one engine, keep the speed up.
when in normal flight it only needed 1/2 throttle, sounded better also.
the DC/ I now have has 2 os wankels in it not flown yet. it is also a topflight model, smaller than yours .

jaka

Hi!
All models airplanes ...and full size airplanes benefit from using wash-out in their wings..especially those with tapered wing tips....this is a fact.
Anoter fact is thar models as well as full size airplanes need low weight to realy fly well. Weight is never a good thing in a scale model! There are exceptions to this rule of course and that is sailplanes.To move forward, penetrate the air, they need weight.

There is also a third rule one must follow if you want a good flying scale model and that is to keep engine size/ weight down. To powerful engines and the model will fly like a pattern airplane. Too heavy engines and the airplane will needd bigger/heavier tanks, more fuel, bigger/heavier engine mounts, studier/heavier construction overall and heavier/sturdier landing gear and so on and on.

The problem is always knowning which is the best engine size is for what model...
For my DC-3, weighting 3,6kg and swinging 3-blade 10x5" carbon fiber props, the OS .26 fourstroke is an ideal engine. Anything bigger than this and the airplane will fly too fast.

skypupmut

you still have a throttle control,
my DC3 need 8 ounces of lesd in the nose anyway.
might as well be motors,
bigger motors at half throttle use less fuel than the smaller ones , working their tails off to keep it flying
the DC3 you need to build the tail as light as possible, less weight up front needed to ballance it.
with a bit bigger engines ,a single engine flight is a non event,
loose an engine with the smaller ones and the only choice you have is point the nose down
and cut the remaining engine to keep control of the plane.
pre previous DC3 I flew with the 46`s would take off at 2/3 throttle with autority
and with only one engine going would still do touch and gos and turn right and left and climb quite well.
if you want to loose your model early in it`s life, use small engines, pray that you do not loose an engine in flight.
my 2 c. worth and past experience in 55 years of modeling.
a little bigger engine goes a long way in the longevity and pleasure af flying.

regards

Jean

marko509

This was the reasoning behind him using the FM wing on the Paris White fuse... "My reason for substituting the "Flying Models" wing for the Paris White wing was that the ribs are shown more clearly and full size on the FM plans and not Paris' plans; thereby, making construction a little easier." "As to the slight difference in the wingspan, I do not recall this being a problem at all. If there was a difference in the center wing chord, it surely was very slight. It is possible that I had to slightly "cut and fit" the wing mounting area on the fuselage."

I agree with him to a point- I would much rather cut out each individual rib than block sand a stack of the to shape.

I have not received the plan yet in snail mail, so I can't comment at all about the FM fuse. I have a smaller plastic model (not sure what scale, ws is about 12") and I agree with you- not only are the sides flattened out (as compared to the Paris White plan) but so are the top and bottom. It is too bad, as I have all of the fuse formers cut out already! I'm not sure how to trim away at all of the formers in a scale method and get them to turn out. I will probably leave them alone.

"By the way, I just remembered that my K&B .61 powered DC-3 was very nose heavy. It required about 8 oz. of lead in the tail to balance. The use of your .46's may just about eliminate the nose heavy problem." Doesn't sound like I need to worry about the tail being heavy, as long as I use common sense construction. It is good to know, as now I can consider mounting the elevator/rudder servos in the tail and avoid long sloppy linkages.

While it may be awkward to build and utilize the jig to build a straight fuse, it shouldn't be too difficult. I've used methods much like this in various areas of home construction, with excellent results. Did you sheet/plank the side of the plane 2" down the centerline of the fuse before removing the half-completed side (as the plans specify)? I might even consider temporarily fastening diagonal braces on the insides of the formers to help hold the shape- I can always remove them when I have the other side completed.

Osman, I would love to see that washout file you have, but it will need to be done as a .pdf file- I do not have autocad. I believe that in the instruction manual for the Top Flite DC-3 it instructs you to place a piece of wood under the trailing edge of the outer wing to build-in the washout. I'm pretty sure that they specify the actual size of the block of wood- wouldn't I be able to scale that block up to the scale of the Paris White (or FM) wing?

marko509

this is a test post to see if I figured out how to upload pictures...