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Old Oct 30, 2012, 12:19 PM
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electricgeoff's Avatar
United Kingdom, England, Lincs
Joined Apr 2011
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Originally Posted by bettsmums View Post
I decided I needed to have retracts for my Buffalo Airlines DC-3. The goal was to keep it as cheap as possible and only use hand tools. I think it took a total of around 5 hours to make and install everything. The only extra parts required were a short length of brass tubing, 1/4 by 1/16 brass, 4-40 quicklinks, control linkage, two cheap micro servos, 1/16 music wire and a small piece of G-10 epoxy board for the control arm.Of course the first one took the majority of the time. I cut apart the stock landing gear with a hack saw. The trick to cutting the slots in the landing gear legs was to use two saw blades mounted on the hacksaw at once with the teeth pointed opposite directions. That kept it fron sliding sideways while I cut the slot. The brass tubing keeps the slot with the fixed part of the brass from spiltting. I used C/A glue to hold the lower arm and brass together. The joints are moving on small pieces of 1/16 inch music wire. I also moved the speed controls back into the fuselage (where they should have been to begin with). They probably still would have fit in the nacelle with a little more carving. The bottom of the landing gear sits flat on the foam when extended and the pivot in the center of the landing gear leg fits together tight when pushed from the rear by the servo. It seems pretty sturdy when extended. I am going to fly it before I carve some more foam to make the nacelles look better. For the scale guys yes I know the wheel moves forward a little more than real but that was the best I could manage with the existing landing gear. I also fly from a paved runway so I am not worried about extra force applied from grass. It has been a little windy for a test flight but hopefully this weekend will work out. I can't wait to see the gear cycle in the air.
Clever and so simple.

EG
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Old Oct 30, 2012, 01:36 PM
Flick lives
BladeHead's Avatar
beautiful, picturesque Southern New Jersey, USA
Joined Dec 2008
474 Posts
Almost completely off topic

Hurricane blew over and we lucked out... no damage and power never went out! When I arrived at work this morning, things at the airport were verrrrrry quiet. That will change.
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Old Oct 30, 2012, 04:16 PM
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USA, CA, Santa Barbara
Joined Jan 2011
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I've been flying their C47 version. Absolutely GREAT flyer with perfect tracking. It will even roll fine and fly inverted. The scale take off and landing are beautiful.
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Old Oct 30, 2012, 04:35 PM
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electricgeoff's Avatar
United Kingdom, England, Lincs
Joined Apr 2011
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Originally Posted by BladeHead View Post
Hurricane blew over and we lucked out... no damage and power never went out! When I arrived at work this morning, things at the airport were verrrrrry quiet. That will change.
That's good to hear you had no damage.

Thoughts and prayers with those who haven't been so lucky.

EG
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Old Oct 30, 2012, 04:36 PM
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electricgeoff's Avatar
United Kingdom, England, Lincs
Joined Apr 2011
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Originally Posted by frwudl View Post
I've been flying their C47 version. Absolutely GREAT flyer with perfect tracking. It will even roll fine and fly inverted. The scale take off and landing are beautiful.
Is that the Dynam one, marketed over here as Top Gun, but in RAF markings, not US?

EG
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Old Oct 31, 2012, 01:14 AM
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Joined Aug 2004
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Laurence - your question about rudder lock had me dig out my old DC-3 flight manual!

It says during a side slip, around 100 kts or less it is possible for the rudder to go to full travel and stay there, due to the massive aerodynamic overhang on the surface (a feature not on the Dynam model.) To recover, discontinue the slip and the rudder will recenter...so the book says. It was talked about when I was trained on the DC-3 but never demo'd, and I didn't once consider doing the maneuver when I instructed at the commuter airline.

In the early 1950s, some of the DC-3s performance and handling quirks came to the attention of the CAA, as it wasn't even certified as a Transport category airplane (that didn't exist in 1935 when she first flew. So the CAA had the NACA do a more complete flight report. There was quite a ruckus to ground the old girl as unsafe, but the regional airlines of the 1950s said if the 'DC-3 is grounded we are out of businnes! Finally the CAA relented under the economic pressurre and grandfathered it in.

Here'e a 1953 flight report analyzing what control and stabililty issues the DC-3 has especially with an aft cg Russ Farris

http://ntrs.nasa.gov/archive/nasa/ca...1993083829.pdf
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Old Oct 31, 2012, 05:21 AM
The sky is the limit
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Belgium, Vlaams Gewest, Hasselt
Joined Aug 2012
199 Posts
Hey Bettsmums, nice to see that easy to make retract system. I'm tempted to apply that mod to my model as well. Please keep us informed about its behavior long term, I sometimes doubt about cutting even more from that brittle plastic undercarriage, I also would create a kind of over-centre mechanical lock so touchdown forces could be absorbed without being transmitted to weak lightweight servo's. How do you cool de ESC's in the fuselage?
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Old Oct 31, 2012, 06:44 AM
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Belgium, Vlaams Gewest, Hasselt
Joined Aug 2012
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Hi Russ, thanks for posting the link to the DC3 test report, I never read it before (spent nearly all my time fff instead of www). Regarding the rudder hard over recovery, it seems logical to advocate to eliminate the sideslip to recover from it, but how do you eliminate the sideslip if you are physically unable to move the pedals (the report speaks about more than 180lbs pressure !).

Reading the article brought back some good feelings of battling the flight controls of not so harmonic airplanes to display them attractively, to crowds of digital era people during historic airshows or pleasure flights. The most harmonic airplane for me is the Stampe SV4b aerobatic biplane, it just does what you are thinking of in your head, with little well balanced control forces. Maybe the Bucker Junckmann/Junkmeister is similar or better, but I never had the chance to fly one.
My biggest disappointment in control harmony was the Spitfire, elevator remained too light as speed increased making it easy to over G or accellerate stall in a turn, but aileron stiffened up at an increadible rate. That's when I understood the funny top of the stick, being rather skinny I needed my two hands to roll it at cruise speed. Flying a nice elegant barrel roll in that aircraft required some fine control of your motoric forces between the brains and hand movements and displacement.

The no feedback or stiffening up of the sticks on our transmitters deprive us of basic sences every pilot of real aircraft take for granted flying their machine. R/C is a different world. In my club I haven't told the people I have flown real airplanes before because I just want to be one of the members. Sooner or later they will find out, but I'm glad to now just listen in on their excellent R/C advice, but often have to keep my lips together hearing them giving aerodynamic and flying that is miles away from reality. They realize my aviation knowledge is above average but still haven't figured out how my alter ego filled the first fifty years of her life.
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Old Oct 31, 2012, 09:31 AM
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Jacksonville, FL
Joined Jan 2006
186 Posts
Cooling Fuselage Speed Controls.

I already cut a cooling scoop and exit for the battery as it did not come with one. The speed controls will use the same cooling air. The servo does not really take any force as the link from the back of the wheel to the wing takes almost all the forward and backward motion. The vertical force goes directly through the landing gear legs. All the servo is really doing is holding the landing gear leg vertical. The landing gear legs can really only move forward. There is no backward motion because of how the joint works. I don't consider the landing gear any more brittle than the original one. The plane is really light and doesn't stress the gear all that much. I will keep you informed on how it works out.
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Old Oct 31, 2012, 04:05 PM
Always puts it on the numbers.
Spookeay's Avatar
United States, AL, Sylacauga
Joined Jul 2012
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The 2 new DC-3's came this morning. the one I am working on now is going to be the same as Jim's... but It's going to be Navy.... I got most of the fuse and tail painted today, still waiting on the wings to dry so I can mask them off for the orange .
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Old Oct 31, 2012, 04:14 PM
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United States, WV, St Albans
Joined Jul 2011
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Originally Posted by Spookeay View Post
The 2 new DC-3's came this morning. the one I am working on now is going to be the same as Jim's... but It's going to be Navy.... I got most of the fuse and tail painted today, still waiting on the wings to dry so I can mask them off for the orange .
Looks good so far. How do you prep the foam for painting?

Jim
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Old Oct 31, 2012, 04:33 PM
Always puts it on the numbers.
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United States, AL, Sylacauga
Joined Jul 2012
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Wipe it down with acetone then 91% alcohol. I's not going to be exactly like yours but similar. I'm using a naval officer transport version that's in a book I have here at home. Non combat.
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Old Oct 31, 2012, 07:23 PM
Always puts it on the numbers.
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United States, AL, Sylacauga
Joined Jul 2012
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Well this is as far as I have got tonight. I had better stop now..... Fooling with all this soft paint I am going to mess something up if I keep jacking with it... You can only do so much in a day.



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Old Oct 31, 2012, 07:49 PM
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United States, FL
Joined Mar 2012
571 Posts
You have done an excellant job on that DC3! How do you get such sharp lines between the colors? Please tell us your secrets I look forward to seeing it up in the air soon I'm sure Did you buy these as the kit version from the Nitroplane sale?
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Old Oct 31, 2012, 08:03 PM
Always puts it on the numbers.
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United States, AL, Sylacauga
Joined Jul 2012
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Frog tape..... It's all about Frog tape for sharp lines... LOL......... Yes they are kits from Nitro. I am thinking I will do the other in Early Delta Airlines livery...... But one at a time for now, one at a time. I get so excited painting these things I half-Tu pull my self back and let things dry and set up.....
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