B 24-D Liberator - Page 6 - RC Groups
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Sep 09, 2012, 01:20 PM
Registered User
Here are the gear and sprocket units. The sprockets are 3/4" in diameter with a 1/8" hub hole where small black thrust buttons will hold the 3/64" wire shaft. The gears are 1 1/4" in diameter with a 1/4" hub hole where white large thrust buttons will hold the 3/64" wire shaft. .

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Sep 13, 2012, 12:47 PM
Registered User
Here is the drive train which will transfer the rubber motor power to the propellers.

Nov 29, 2012, 10:46 PM
Registered User
Just wanted to check in...I've been so busy I haven't had much free time for the Liberator. I still look forward to building and flying it. I'm working at a local bakery now, I was dishes, do the laundry and clean. I looked into upgrading my graphic design business but was unable to get the grant I was hoping for...a lot of time spent preparing the application. I'm trying to get back into college to finish my major in Art Education and earn a teaching certification. So I've been very busy with that, too. I'm writing a book which BTW includes several references to free flight and I've been drawing as well and so when I feel the creative process flow I go for it!

Dec 12, 2012, 07:11 PM
Registered User
I've come up with a test bed design for the Liberator. It's basically the completed airframe but without the "frills"...a box fuselage covered with tissue. The wing nacelles will be minimal. The stab and rudder will be complete, like a finished model would be. I'll be able to try to fly the bed and hopefully get an idea of how a completed model would behave in the air as well as how the drive train will run. If I need to implement the tools of torture for changes, I won't have to worry about scars on a contest model. I'm not sure when I'll be able to buy the wood needed but I'm looking forward to moving ahead with this experiment and go "Where no man has gone before".

Jan 28, 2013, 12:20 AM
Registered User
I'm about ready to order the wood for the Liberator "test bed". It's going to be a simplified flying model test bed. I thought I would learn a lot building a kind of flying prototype first, before attempting a competition model with so much unknowns. I'm concerned about the needed strength of the fuselage. I'm thinking it will fly on 3 loops of 1/4" rubber, or the equivalent. This test fuse will be just a box without the formers which would give it the rounded surface. The plan calls for 4 - 1/8" sq. longerons with vertical braces and diagonal braces in every bay on all four sides. I want to get away with as light a structure as possible. Easy Built Models contest wood comes in "orange" sticks, which will do, I'm sure, and in "red" sticks, which are advertised to be used in most cases where strength is needed but also light weight. Once I get the fuse tissue covered it's going to be darn strong if I go with the heavier "orange". I believe "orange" is used in the Gypsy, for example, but if I remember the Gypsy does not use diagonal braces. I'm thinking "orange" for the four longerons and "red" for all the braces and cross members.

The wing ribs will be 1/20" 4 -6 lbs. and the nacelle ribs will be 1/16" 4 -6 Lbs. C grain. There will be a single main wing spar of "orange" wood and the other spars will be 1/16" sq. "red" sticks. The LE and TE will be soft wood so I can carve in the shapes.

Designing the Liberator for free flight was a bear. The RC plan I bought and have been using as a guide had to be simplified at every turn but I believe I have it now good to go.

I thought I would use tiny coil compression springs between the thrust bearings and the props, around the prop shafts. That way the springs will push the props forward onto the 45 degree bend and I won't have to glue on the props to the prop shafts.

Mar 24, 2013, 01:34 AM
Registered User
I haven't been able to get the Liberator out of my mind. I was going to use the same weight balsa I'm using for the Thomas Morse Scout. It's a good thing I didn't buy that weight wood in bulk for the Liberator. It's way too soft to withstand the stresses of four propellers in the wing. Another problem was how to wind up the rubber. If I wound from the front I would be turning the propellers around with each winding revolution. I had a good conversation with Lee Campbell the other day. He offers a great stooge which I am planning to buy from him. And so I'll be able to secure the propellers from turning, secure the front of the plane and wind the rubber directly from the rear. WooHoo!

Dec 21, 2013, 04:29 PM
Registered User
I'm still interested in building / flying a Liberator. It would be, if i do, rubber powered still, but each of the four propellers would be independent and wound separately. Is there any rule in competition which disallows extended motor sticks beyond the wing's TE? I've looked at the single rubber motor / gear and chain drive from every angle. I don't see how it can be done successfully. The size of the rubber motor needed would have to be really heavy and so IMO, there would be major difficulty in winding. My system for holding the motor in the "all wound up and ready to fly" mode just didn't seem workable. It required a metal tube inserted in a hole in the prop shaft and fuselage, and then pulled out to release the motor to unwind. I didn't like the exposed chain either, and the weight of the combined drive train parts was considerable. In no way do I consider my efforts a failure. Maybe my experience will help someone who wants to build a free flight model with multiple props driven by a single motor and approaches that in a way no one else has. My plan is to build the Guillow's plan with contest balsa, use all the weight saving methods, and build balsa nacelles to replace the plastic parts in the Guillow's kit. All I need to buy is the plan, which I can do at their site... all because I want to use their plastic canopies.
Dec 22, 2013, 07:11 PM
Culper Junior
Here's a nice vid of Chris Starleaf's B-24 at Geneseo this year. Maybe you could get on the Flying Aces web site and ask around for their input on your model. I don't think too many of us here have tackled such a complicated model.

Rubber-powered B-24 flight, Geneseo 2013 (1 min 0 sec)
Dec 22, 2013, 07:34 PM
Registered User
Best I can tell, the proper response to that is, Wow!
Dec 22, 2013, 10:03 PM
Registered User
Yeah, WOW! Nice flight. I didn't see any motor stick extensions beyond the TE. That's what I needed to know. I think I have everything else covered. A good thing about not using a single motor is each propeller down and right thrust can be adjusted. Thank you for your interest and for the video. Thrilling!
Dec 23, 2013, 09:00 AM
Balsa Flies Better!
Hi Kevin

In FAC competition- I think the rules allow for motor sticks beyond the nacelle. Vance Gilbert- one of the gurus-is flying a Twin Jenny that I think originally was limited to a nacelle, but has since added a longer motor stick I suspect in order to increase flight times which were previously less than 30 sec. IIRC. Having seen the bird fly- I thought the flights were quite impressive anyhow! A single engine Jenny is a pain- a twin- a nightmare....

The other guy to look up is Dennis Norman who's had an article in MA on how he built a 4 motored Lanc- also without using extensions- that was some years ago- probably over a decade.

Dec 23, 2013, 01:22 PM
Registered User
Originally Posted by aeronca52
Here's a nice vid of Chris Starleaf's B-24 at Geneseo this year. Maybe you could get on the Flying Aces web site and ask around for their input on your model. I don't think too many of us here have tackled such a complicated model.
Where is Chris posting his build threads these days? I remember his DC-4 thread, I think it was on SFA, which then had some troubles. I spent a few minutes checking Hip Pocket and SFA and I didn't see a thread about that nice B-24...
Dec 24, 2013, 05:10 PM
Culper Junior
Somebody also had a rubber powered B-24 in Flying Models several years back, that might also have been Dennis Norman.

If I remember correctly that whole issue of FM was B-24 centered.
Dec 25, 2013, 02:48 AM
Sticks, Tissue & old Diesels
brokenenglish's Avatar
What a fabulous B24 video!
Concerning Kevin's "motor stick" questions, if you look closely at the video, apparently there are no external motor sticks, but the engine nacelles appear to have been extended forward (and perhaps aft, as well), to obtain a little motor length.
Excuse me, you guys know much more about this than I do but, obviously, extending the nacelles forward is also going to help to get a reasonable CG position, whereas motor sticks extending to the rear would do the reverse... (and so would a bigger motor in the main fuselage).
Anyway, it's a great achievement!
Dec 25, 2013, 08:59 AM
Culper Junior
In the last year or two I remember reading about how some flyers are getting longer motor runs out of short nacelle enclosed motors. It was either Flying Models or the Flying Aces newsletter.

Have to try and remember which one, but I'm leaning toward FM at the moment.

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