Spar Strength on a 108" C-130
10-10-2013, 04:34 AM
#28
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I don't remember what the weight is, its been over a year since I weighed it. Here is some other info though. Wing span is 103" , motors are turnigy 4250 600kv(equivalent to .32 glow motors), Turnigy 60 amp speed controls, (4)Turnigy nano tech 4 cell 2650mah. I made the 4 blade props out of two, two blade 11X8 props. The plane was designed by Skip Mast a long time ago. The fuselage is fiberglass, the wings and horizontal stab are foam core balsa sheeted, then fiber-glassed. The plane flies like a big trainer.
Aaron
Aaron
10-10-2013, 05:03 AM
#30
Thanks for all that info. Now I can give you all the data you need.
For the last three years, I have carefully studied the information you provided just 20 minutes ago. My friends at NASA also ran it through a few algorithms. They are currently laid-off due to the government shutdown. So luckily for us, they had some free time to analize this with three of the local crackheads in Cocoa Beach.
Providing there is no crosswind component, or wind, temp is 75°F, and elevation is 14 feet ASL;
The takeoff roll will be 62.4 feet when full power is immediately applied.
Vr speed will be 28.3 mph
Max speed will be 71 mph in level flight.
Landing speed should be at 29.6 mph
Max maneuvering G load at 71 mph will be 11.6 g's
Weight will be 15.6 lb dry. Assuming 6 oz. tanks for each engine, weight with fuel will be 16.2 lb.
Ground roll after landing will be 181.0 feet, if brakes are not applied
Let us know if we can do anything else to help you out.
Am I prettier than the other two?
For the last three years, I have carefully studied the information you provided just 20 minutes ago. My friends at NASA also ran it through a few algorithms. They are currently laid-off due to the government shutdown. So luckily for us, they had some free time to analize this with three of the local crackheads in Cocoa Beach.
Providing there is no crosswind component, or wind, temp is 75°F, and elevation is 14 feet ASL;
The takeoff roll will be 62.4 feet when full power is immediately applied.
Vr speed will be 28.3 mph
Max speed will be 71 mph in level flight.
Landing speed should be at 29.6 mph
Max maneuvering G load at 71 mph will be 11.6 g's
Weight will be 15.6 lb dry. Assuming 6 oz. tanks for each engine, weight with fuel will be 16.2 lb.
Ground roll after landing will be 181.0 feet, if brakes are not applied
Let us know if we can do anything else to help you out.
Am I prettier than the other two?
Last edited by Airplanes400; 10-10-2013 at 05:17 AM.
10-10-2013, 05:45 PM
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With regards to spar strength, I would research other plans for planes with similiar wingspan and wingloading. One thing that always puzzled me, was whether the spar should be flat side facing up/down or forward/backward. Seems like the skinny edge of the spar should be positioned up and down to give the most strength during loops and high G maneuvers. But yet I see plans where the spar is laid flat side down. Both arrangements should always be web sheeted.
10-11-2013, 03:17 AM
#36
The web sheeting bonded to the upper and lower spar caps is what makes up the spar in either a wide or thin spar cap configuration, the thicker the overall airfoil, the stronger the spar is by pushing the caps further away from one another. So span wise tapering the spar caps makes sense due to the fact that the load diminishes the closer you get to the wing tips allowing you to remove excess weight.
Bob
Bob
Last edited by sensei; 10-11-2013 at 10:25 AM.
10-17-2013, 11:25 AM
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I have made quite a bit of progress since i last made it on here, my current issue is deciding how i want to make the flaps hinge.
I wanted to use a track like the next picture but so far this seems very flimsy, there is a lot of slop once the flaps are rolled all the way back. I also wanted to get more downward deflection.
I am probably going to have to use longer carbon rods and guides in order to get rid of all the slop when the flaps track backward. as for the downward hinge and deflection, undecided. I want to keep the model semi scale and keep all linkages within the fuselage.
I would prefer to use a track like this but dont know where i could buy such a thing, may have to look more into it if i cant make my current design work.
I wanted to use a track like the next picture but so far this seems very flimsy, there is a lot of slop once the flaps are rolled all the way back. I also wanted to get more downward deflection.
I am probably going to have to use longer carbon rods and guides in order to get rid of all the slop when the flaps track backward. as for the downward hinge and deflection, undecided. I want to keep the model semi scale and keep all linkages within the fuselage.
I would prefer to use a track like this but dont know where i could buy such a thing, may have to look more into it if i cant make my current design work.
Last edited by jordanorville; 10-17-2013 at 11:38 AM.
10-18-2013, 05:00 AM
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These might inspire you.
Keeping 'em light and reliable is going to be the Devil's job.
It probably offends your sense of scale integrity, but simple might be the best option.
Keeping 'em light and reliable is going to be the Devil's job.
It probably offends your sense of scale integrity, but simple might be the best option.
10-18-2013, 05:46 AM
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I am not offended at all. This is my first scratch build and though not the toughest, it is not simple either. I did some reading and have seen that track design come up a lot. this morning i have been toying with this method, I think it will work well so long as the torque rod can move for and aft with the flap
The tricky part seems to be making that happen.
10-19-2013, 05:28 PM
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his bird will have retracts, brakes, fowler flaps, functioning ramp/door, cargo rails,
I don't see this coming in at 15 lbs.
20+ lbs more likely.
I know of a 1/12th scale Avro Lancaster [ 102 in span ] that came in around 15 lbs or more. It was built light mostly of blue foam covered in Brown paper and used 4 x 15s It did have retracts and flew in a very scale like manner. I mean the real one was rolled and did fly inverted!
http://youtu.be/1IsRp_QLwd8
Last edited by j.duncker; 10-19-2013 at 05:37 PM.
10-24-2013, 04:57 PM
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I want to use 4 electrics rather than gas simply for the reliability. That being said i dont know squat about them. I am going to estimate that the model will wigh between 15-20 lbs, 20 lbs max as a high estimate. I have 2 2650 mah sky lipo batteries, I would like to use them if i can get the kind of power and flight time out of them that i will need. I was looking at using a 25 size outrunner as recomended by a friend but am unsure that this battery will cut it. http://www.rchotdeals.com/products/O...-lb-plane.html I have the option to use 730 840 or 1000 KV and a 50 or 60amp speed controler combo. Looking for input on this setup or other alternatives. I would like to know what kind of flight time i might expect from this setup flying at 60-70% power, and wheather or not i can run two motors off of one battery in order to save money, weight, and space. I also need a to know what prop to use, i would like to use a 3 or 4 blade prop, 11.5" with squared tips. I would likely buy a 13" prop and cut it down in order to square them.
