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C-130 versus FT Guinea Pig?

#1
I'm wondering how much trouble it would be to modify the FTGP standard size to more like a C-130 tail. I have ideas for drops, but I'd like to have a larger opening that matched the interior space better. The downloaded Picture explains what I'm working towards.
USCG_HC-130H-b.jpg
 

b-29er

Well-known member
#4
Sounds awesome, but i would probably run some 1/4 " rod or some CF tube along the top corners of the empennage, and also along the rudder Considering how the C-130's empennage essentially ends after the first third of the empennage, you will need all the strength you can hold on to if you want the elevator to be true and not floppin in the breeze. You could also just square off the Guinea's empennage's top-down profile, that way you wind up with that same guinea look from the side, but you get the wider door to push stuff into/out of.
 
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#5
Thanks Merv, Casey and B-29er. Good points b-29er. Looking over the Herc tail compared to the GP, I think I'll leave the GP tail as is, the fuselage body ending pre-elevator. Just widen the top and floor plates straight from base of cargo door to the tail box. Possible close the tail box or add an internal vertical support.
Building a Herc split elevator is not impossible, just a touch much for me right now. But I was looking at Herc rudders. Maybe extend the forward fuselage support almost to the wing trailing edge, running the rudder hinge straight up. This would give me a top rudder location for Position/Anti-Collision lights.
Empty CG will be comp'd by reinforcing or extending the Nose/Forward Fuselage. By the looks of the GP, cargo should sit between the leading edge and trailing edge of the main wing. This should be close enough to CG center to fly right. Most Herc drops I was involved in were done at a slow speed, quarter flaps, with a slight nose up angle. Everything (Everyone!) slid out fine, then Flaps Up/ Grab Air! LOL
 
#6
Casey, pictures as built and beyond, plans after crashes... er... flight testing, yeah, that's it.
b-29er, thanks for the ID pic of the Herc gunship. Nice. Almost makes me want to build a GP with BFG's? Eh?
 
#7
WHEELS? Change to 2.75's rear, two axles, instead of dual trucks. Easy to build, link, single servo retracts, or torsion action mains. Drawings later today. Let me know what you've got, or what you think!
 

tamuct01

Active member
#8
I had plans at one point to made the single, large FTGP door into a split door like the C-130. This was after the FB door started to delaminate when using a single, underslung servo on the door. I could never get a split mechanism working with enough throw to fully open the door. I went back to the single door design, but instead of using a normal control horn, I made a U-shape wire bent through a coffee stirrer. Each end of the wire is attached to a long servo arm and the servos are installed in the bay, with the base of the servo poking through the side of the fuselage, but hidden by the wheel pants. The servos are synchronized in my Taranis and lower the door slowly. The whole setup is pretty strong and distributes the forces on the door across the U-shaped wire instead of focused on a control horn.
 
#9
tamuct01, love to see a pic or even simple drawing of that action. My idea was to reinforce the sides of the single door with skewers hot glued and wiped off extra with U-shaped excess foam. Then glue horn onto skewers. In one wheel cover base the servo, axle wire bent at ends to attach to long servo horn, then cross floor, bend up end same length as first end with small loop, or attach to like servo arm. Anchor lone end with modified horn. Wire both ends to horns on the door. I also like your idea of direct connect servo arm to door. With torsion bar link across/under floor to servo arm on opposite side, that uses only one servo. Also been working on cam for possible upper door action. Will post if I come up with something that works.
 
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tamuct01

Active member
#10
Scooter, here's a couple of pics of the mechanism on my FTGP:

From the inside, the pair of servos work in tandem to lower the U-shaped bar. There are triangle bends in the wire to adjust them to the same length. I had to cut notches in the fuselage around the door to allow for the control horns and wire to pass through without binding.

IMG_2806.jpg IMG_2807.jpg
Here's a close-up of the servo on the left side. Note that the body of the servo passes through the fuselage, but is hidden by the wheel pant. Finally, there is an image of the U-shaped bar that supports the door while raising and lowering. This was all added after the original coat of paint, and I've never bothered to fix it. :)

IMG_2808.jpg IMG_2809.jpg
 
#11
Oct. 21st. 2018. Ah-h-h-h! Now I get what you meant! (Slapping forehead...) My idea/thought was trying to cut the action down to one servo. My U-shape wire crosses at the bottom/hinge of the cargo door. The uprights on each end are mated to long servo arms. I planned to reinforce the door sides with hot glued in the side slots, Bar-B-Que skewers. Just inside the skewers about the same length up the door where your wire goes under, I install the wooden horns. My servo will sit pretty close to where yours does, and one arm links to a servo arm on the crossover. I'll get to drafting a rough sketch here in a minute or two, pho-tog with me cell, email to my email, save and add to this. Yeah, long process, but it works.
The reason I want to cut down to one cargo door action servo? I want one in the other wheel pant for a easy-peasy retract system for the main gear. If I get industrious, I'll snap that and add it also. Here. Tonight. If I ever stop typing. (Ha)
Question: I can find 20" X 30" X 3/16" (4.8 mm) white Pacon or Elmer's foam board at my local art supply store. Is this the size of Adams? Or is Adams or DT 1/8th (3.2 mm)?
 
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#12
Oct. 21st, 2018. I saw the YouTube video of Peter's early Pink Pre-Guinea. So, I will mod the nose and tail box as the Pink Guinea leaving the rudder and elevators. Maybe narrow the nose a touch. If you don't know... on Peter's channel: "Fireworks Versus RC Cargo Plane".
Here are two screen snaps from the video...
PinkPrePig09.png
PinkPrePig17.png
 
#13
Tamuct01... here is my quickie idea 2D from Paint on my laptop. Hope this explains my version of the cargo door better. And I added the Main Retracts since I wanted to have a visual of both while I was at it.
RearGuineaCargoDoorDetail01.png