Propwash in Pa

I want to tap into this vast pool of intellectual knowledge and garner some feedback. I am currently building a Sig Astro-Hog Bipe and am making the following modifications from the factory kit.
1. Dual aileron servos
2. Split elevator with two pushrods
3. Sullivan tail wheel assembly
4. lightly glassing the landing gear assembly from the inside.
What changes have you made or wish you could have while building this plane and why? [/font]

Dsegal

I used the original kit plan to build a 75% version. See http://www.rcuniverse.com/forum/m_14...tm.htm#1451989
If you omit the plastic headrest life will be simpler. I also added a hatch under the nose for access to the fuel tank. No one was ever sorry to have easy access to the tank. Two aileron servos will allow you to set up aileron differential and even flaperons. But two elevator pushrods seems like needless complication to me.

Gringo Flyer

My Feedback: (18)

I plan on getting a hog bipe in 2005 and have alrady done a bunch of research on the plane. Its a really popular plane and there is a ton of info about it here on RCU. Just do a search on it and you will have more than an evenings worth of reading to do. You will defeinetly find info on the landing gear and dual aileron servos.

Nuker

I actually sheeted the plastic head rest, much easier to cover

I changed the shape of the tail, just to make it a bit different, used the sullivan tail wheen assembly and did pull pull on the rudder.

Bob

Sense963

My Feedback: (10)

Hog Lovers Unite! Fubar Hill has an excellent website devoted to the hog. Mine has a history, and after 9 mos of flying it, I put it in hard, so a major rework was in store. Dual aileron servos were a good thing. Even though the plane was orig designed for an S-148 driving the ailerons, I wasn't too comfy with it and installed duals. The plans now have the design mods to do this, but mine was homecooked. I also made a bigger rudder (more surface out the back, height is stock). This gives me a better spin and a LOT of authority, without looking out of whack. I also put a Hitec digi servo on the rudder and arranged a pull/pull. Very tight and responsive! I would NOT, however, monkey w/ the landing gear. You hear a lot of guys moving it up and what not.. If you do this, be prepared for a mess of porpoise landings, as the CG is now extended further past the fulcrum (wheels hitting the ground) and this causes bouncy landings. If you value your props and like to put it down in one piece, leave the gear where it is. I doubt you would regret a good glass job in the cavity on the inside, though, as long as you don't go wild w/ the resin. I am also not a big fan of hatches around the nose; they merely weaken a critical area. I have no hatch and see no personal reason for it. But that is only my opinion on hatches. If you want one, it's your plane! If you want to see photos of the rework in process, www.mprcf.com then "Member's Projects..." Click Brent's Barnstorming Hogbipe to see some shots.

Propwash in Pa

Brent,
Thanks for the link - nice job. You are obviously one proud Hogger. Couple of questions. What engine did you use and how has it performed? Did you go with independent elevator pushrods (2) or just one as designed? Also, I did install a hatch plus will be putting a stringer down the sides of the fuse to produce a more rounded and realistic appearance.

As far as lightly glassing the inside of the landing gear plate, yes, it can be done cleanly. If you are interested, I will describe the technique that I use. Just let me know.

John - 373786

lrb75

My Feedback: (12)

My kit came with a small bag of parts and an addendum to show the dual aileron setup. If you already have the kit it the update might be available from SIG. Any new kit should come with it. Only deviations from stock I made were pull-pull on the rudder and moved the elevator servo to the rear of the plane with a direct linkage. Flys great with a Saito 91 and has been very durable. One problem I had in the begining was breaking the stock engine mount on moderately hard landings. Don't use self tapping screws they seem to overstress the mount. Drill and tap the mount and use stop nuts underneath. Have fun.

Sense963

My Feedback: (10)

I agree w/ lrb on the engine mount. If you have the same composite mount sig has now, I'd drill thru and use locknuts instead of screws, ESPECIALLY on a big engine. Propwash, I run a 15 year old OS91 (not even surpass!) with a 15x6 APC. How does vertical grab you??? I count myself lucky to have such a winner for an engine. The newer crop of surpass 91's seem to be loaded w/ power. I run byron's 10% 4C and it runs like a champ. I made the switch from 14 to 15" props last spring and haven't looked back. The perf delta is unreal.
Regarding the dual elev servos: why? A wire links the two, if you use some thin CA in the holes they'll be rock hard and won't wear out. I run a std sullivan gold-n-rod back off of a hitec 605 or 645. 645 is it. I braced it well as close as I could and it's working just fine. I have no doubt you can do a clean glass job on the LG compartment... I'm just being an anal old guy saying be judicious w/ the resin! Now I HAVE pulled the gear out a couple times on mine, and I think you'll like the extra beef in there. I'd say a 2oz cloth would be the ticket. Maybe a 6. Let me know how it goes, and I would like to see some shots of it when done.

Propwash in Pa

Brent,

Thanks for your input. Just to clarify a point. I am not using dual servos for the elevator, but am using dual pushrods for elevator. With this set-up the elevator halves are not joined. As the two pushrods enter the main compartment with the servos, they are physically joined using two wheel collars. One of these rods are then continued forward to the servo arm.
As far as the power plant, I am using an Ervine .60 2-stroke spinning a 12 x 7 or 13 x 6 APS. Should be okay.

John - 373786

Propwash in Pa

Brent,
Forgot to comment about the glassing of the gear plate. I use 2 oz. glass and install it on the inside of the compartment, across the top of the gear plate and up both sides of the fuse. This is the critical step as it distributes the forces over a much greater area. Also, warming the epoxy with a heat gun will thin it nicely. I use this technique on most of my planes as repairing landing gear plates are never easy.

John

Sense963

My Feedback: (10)

Gotcha...one servo splitting off. Don't know....in my opinion, I would not do it, but if you see a benefit and decide it's something you want to do, it's your decision. Sounds like a good idea, the glassing. I'm familiar with the techniques you're describing, and you'll be in good shape with regard to the strength it affords. As a side note, I'm not a big fan of the wheel collars or EZ connectors. Not secure enough for me to feel good about. If I was doing something as you describe, I would be doing some soldering or something. You're not going to have a large wire run from split to horns, are you? Sounds like a recipe for flutter to me.

Propwash in Pa

I has hesitant about using the wheel collar / 2 rod trick until I followed the instructions for my Great Planes Extra 300S (60 size). This is exactly how they designed the plane and it works very well. On a side note, this Extra with a Surpass 90 on the nose is by far the best flying plane I have ever owned. (I started flying in 1973 with an RCM 60 and Falcon 56). Worth a look.


John Shaffer

Sense963

My Feedback: (10)

Like I said, if it's something you see a benefit in, forge ahead. In my situation, the torque rod is a fine solution and works well, in addition to being a simple answer to the need. I just see split rods as a more complicated solution to something that really isn't a problem, but this is MY opinion, and not to be construed as forcible advice or anything, since it's your plane and your project. Enough on that.
I'm doing my Astro Hog right now, and next on the list is the joining of wings. I've been sanding till my arms are about to fall off, and the vacuum has been doing double duty. That is going to have an OS61FX for power, pull pull rudder, taildragger, a glassed fuselage, and I'm doing Fred Dunn (orig designer) the honor of a replication paint scheme.