This will be my first venture into Giant scale and Gas. Here's what I have already decided on:

GP 1/3 Pitts ARF
BME 60
22x10 prop
JR 8103 Tx

Now here's where you can help. I have read just about every thread here re: the GP Pitts and now I'm more confused than ever. You can help build this plane with your experienced based recommendations on the following:
Servos
Matchbox or not
batteries
Rx(s)
Hinging, Linkages and configurations
Smoke?
Kit modifications (already aware of GP's updates)
Use the supplied stuff (tanks, wheels etc.)?
Thrust and incidence changes for the selected engine

Now I know I could just go crazy and buy the best of everything and add a couple grand to this project, but I am relying on your collective expertise to do what's needed and keep the cost down as low as possible, yet have a great flying aircraft.

I live in Northern Wisconsin so I got a whole bunch of time to complete this project (It's snowing here now).

Thanx in advance guys, I'll check in often,

ddaver

Boy, you ask for a lot, but I'll try. For the others, these are things that I have done and they work fine. My finished Pitts weighs 16.5 lbs. with a Brisson 3.2 and is a superb performer.

Your BME will do just fine. More power than you will know what to do with. Add some 1/8" ply strips inside the engine mounting box for better support for the blind nuts that you will likely want to install.

Add your choice of corner reinforcements at the inside of the fuselage/firewall junction. Without them my firewall pulled loose from the fuselage.

Cut an access hatch at the bottom of the firewall in the lower angled section. Throw away the piece you cut out and replace it with a new 1/8" ply access hatch laid completely over the flat angeled section, fitting it between the raised sides. Space your cuts to be 10mm inside of all the raised edges to permit for screw fasteners. I used wafer head servo mounting wood srews for this. The opening gives you access to all the areas you will want to strengthen or change. The access hatch also provides a mounting location for your ignition battery. Mine is attached to the hatches interior.

I added additional plywood bases and blind nuts at ALL the cabane to fuselage mounting points inside the fuse.

Remove the small balsa tri stock at the engine box and install 1/2" balsa tri strock after adding 1/8 plywood doublers at all exterior sides of the mount box.

Plan to install your throttle servo at the side of the engine mounting box. Determine where this is to be before you add the plywood doublers.

Remove a small piece of covering from the aft side of the fuselage to permit the addition of a light ply doubler at the tailwheel mounting area. Install blind nuts for the tailwheel. While you have the side open, note that the pre-installed antenna tube ends a long way before your receiver antenna ends and that there is no exit hole in the fuselage for the antenna. I re-routed the tube to exit out the top of the fuselage just between the canopy and the vertical stab. After cutting the MonoKote for the fuselage servo openings, add 1/8"x3/8"wide strips inside the fuselage at the servo opening ends for better mounting screw attachment.

Check to be certain that the wing saddles are at equal heights.

Check to be sure that the top cabanes allow for square and true mounting of the top wing prior to finalizing the top wing mounting proceedures. Measure from a reference point on each wingtip to the center of the tail to confirm alignment. Incidences are Bottom wing: zero, Top wing: O to 2 deg. negative (you will prefer the 2 Deg negative), Horizontal stab: zero

Use a 20oz. fuel tank, Dubros' works fine with a slight modification of the bulkhead opening. Add a lite ply plate for the tank and secure with your method of choice.

Two Hitec 5945 coreless digital servos drive all four ailerons just fine with excellent precision and authority. Very crisp on 4.8 volts. 6 volt digitals will make this plane very twitchy (IMO).

Use Central Hobbies 3/16 carbon fiber pushrods and titanium ends for your control rods. Use the suggested JB Weld for the pushrod/end assembly. VERY stiff pushrod. Allows no noticable flex and permits neat knife edge loops. Mount all your flight servos in the tail. I used Hitec 5925 coreless digitals. No problems. I used (1) Matchbox for the elevators. I split the aileron servos for flaperons. Flaperons are not mixed for anything other than separating the servos and channels. Aileron differential is not needed.

Use the most aft suggested C/G that the booklet provides (5-3/4") for your initial balance point. Any more forward makes for very fast landings. I prefer the factory suggested high rates on both the elevators and ailerons for my low rate. I ran out of elevator on landings using the factory low rates and the forward suggested C/G.

Replace the rubber with 4" Dubro, Sullivan, or Hanger 9. Do the same with the tailwheel.

I'm sure there's a lot more that I have failed to provide here, but this is a fair start.

It's a great flying plane. I hope you enjoy it. Feel free to send me a P/M if you want or need to.

Pat Roy

Wow!

Whatta reply and exactly the kind of information I'm looking for. I was leaning towards the 4 aileron servos as I have 4 JR digitals in inventory.

I have printed your reply and will store it with my plans since it will probably a few weeks before I begin the project. (Decided to redo my shop/hangar first)

Thanks,

Dave




BTW, you doing smoke?

You won't need 4 servos for the ailerons. Two digitals and the response will be crisp and positive. The second pair will only add weight and leave a wire exposed somewhere unless you drill the cabane to run the upper wire down through like the one guy did. That adds a lot of unnecessary servo lead, though.

I used Dubro pinned hinges at all flight surfaces. Four hinges per surface. That's one more than the kit calls for per surface. I notched the "V" of the flight surface at each hinge location to allow for the hinge pin. This reduces the hinge gap.

When you are joining the bottom wing panels, use a 20 minute or slower epoxy. You need the time to be absolutely certain of the wing alignment and the dihedral. The correct dihedral angle sets the alignment of the wing "I" struts. Get your dihedral wrong and the struts won't fit properly. The dihedral brace in each of the wing panels is a very loose fit. Just add more epoxy and don't worry about the fit. It doesn't seem to be a problem.

Ignore the part of the plans about fishing your aileron servo leads through the wing panels prior to joining the panels. You will have more than enough open space to run a pull line through the wing for your servo leads after joining the panels. The supplied line in each panel is a little difficult to work with. You don't have to worry about keeping epoxy off the wires that way.

Bipes require a lot more alignment work than mono planes. The instruction book fails to mention proper alignment methods. Wing tip separation fore and aft should match. Wing tip distances to aft fuselage center should be equal. Top and bottom wing will be different totals, of course. Make some kind of reference line on each wing to assist yourself.

It all sounds like a lot of work, but it goes along just fine. It flys even better.

Pat

Thanx Pat

You have been very helpful.

What system did you use to link the upper/lower ailerons?

thanx again,

Dave

I designed and made a custom connection using 6-32 round head machine screws and Central Hobbies 3/16" carbon fiber rods and ends. It's worked out extremely well.

I sent you a PM regarding this subject.

Pat

Thanx again Pat,

But I do not understand PM's or how to recieve them.

Dave

Hi Dave,

This must be the day for Pitts threads. Three in one day. I just posted a thread on mine. Pitts with a DA 50. Just finished the airplane today. I listed most of the detail in the thread. I used 2 ailerons on my first Pitts. You don't want to hear the story of what happened to it. Let's just say it was my error. Anyway, it flew great with two ailerons. I decided to use four this time simply becasue I didn't like the slop in the slave rods that connected the upper ailerons to the lower ailerons. Pay attention to the firewall commets on multiple threads. G.P has certainly improved the firewall. Even using good ply in the newer models. Even so, make sure you remove the flimsy tristock around the mounting box and then reinforce. I pinned mine, added fiberglass and then put tristock inside the box and inside the fuse to the fuse firewall. I put a good bit of epoxy inside the the fuse where it connnects to the firewall as well. I actually could see light between the fuse firewall and the fuse side pannels. Not good. I have posted a few pictures below of how I reinforced the firewall. Hope to do the maiden flight on mine next weekend.

Nice work Roger

I don't know what happened, I was typing a reply and suddenly it vanished.

Anyway, I have been following the other threads as well. Seems to be a lot of alterations and modifications on this plane. I have been building models for over 35 years and lately I seem to be attracted more to the ARF's. I am getting more compulsive (needing to have every new plane that comes out). I am not kidding. I have bought and built (or plan to build) 8 new planes since July. I'm even working on a scratch built 14 foot wing span Trainer.

I am enjoying the ARF's because, quite frankly, I just don't seem to enjoy the time consuming task of setting and glueing all those darn little ribs and formers and gussets and fillets and so one. I am however a little concerned about how the manufacturer did it. What the heck is under that beautiful covering job?

Like I said this is my first venture into Gas and giant scale. It looks like I'll be pushing $2k on this project and want to get it right. There is a lot to learn when it comes to this giant stuff! And why does it have to cost so much? I mean really! $115 for a servo! Does it really cost anywhere near $75 extra to become digital? Talk about praying on the addictions of a few.

What were those guys using to fly those old quarter scale planes 25 years ago? Before anyone had heard of digital. I'm more of a scale and pattern flyer anyways, all out 3D doesn't appeal to me. If I was that interested in hovering around, I would build that helicopter I've got sitting in the box on the shelf.

Thanks to the guys here on RCU for all the help.

Dave,

Talk about praying on the addictions of a few. I have to admit I got a chuckle out of this one. How right you are. I just love the hobby which is my only justification.

You know, a good friend of mine, who taught me how to fly, has about the same years of experience as you. Interesting that you commented about ARF's as you did. He likewise has said, " I couldn't build an airplane form a kit as good looking or as well as many of the quality ARF's that are on the market today". I have to admit that I have never built an airplane from plans or from a kit. I have read many of the threads on the subject and truly appreciate your comments and concerns. It's not that I don't want to build, but rather at this time in my life I simply don't have the time to build. If it were not for Arf's I most likely wouldn't be in the hobby. As a result of ARF assembly and the experience gained from poor construction, I have learned how to do my own repairs and how to do modifications to assemble for strength. One thing is certain, I usually throw away the stock hardware and use better quality products. I sure wish the manufactures would listen to this one. Put more into the Arf kits and charge a reasonable price for better quality. I believe people will purchase on the reputation gained from a quality product.

You mentioned concern about what lies beneath the nice covering. With all the ARF's I have assembled I have learned that it's necessary to look for the weak areas and then reinforce. I have lost two airplanes due to poor construction and one due to my own stupidity. I also lost one due to a cracked ceramic filter in a new Rx. Hard to say if it happened after the crash, or from a hard landing. Will never know for sure. Regardless, I have learned to check for weak areas, and to have electronics tested. Even then there are no guarantees. RCU has proven to be a great resource in getting gobs of information about ARF assembly. You certainly get all kinds of opinions. Some good and some not so good. Through it all the good stuffs filters through and becomes valuable in the assembly process. Take for example pinning and fiberglassing of the firewall in the Pitts. I learned about this on RCU and did so with my first and second Pitts project. Below is a picture of how well the firewall held together after a severe crash on Pitts-1. After all that I had read about firewalls coming lose, look at how well my firewall held. In fact, it held so well the engine took the brunt of the crash. So, maybe I reinforced it too well. Go figure. At least vibration from a gas engine didn't make it come lose.

Good luck with your Pitts project. Let me know if I can help in any way. My thread on Pitts-II is

http://www.rcuniverse.com/forum/G%25...1265113/tm.htm

Take a look and let me know what you think. I have listed the specific details for this project including pictures.

Nice Roger

I have seen your other threads and appreciate the pics and how-to's (even the crash stuff).

Can't wait to here about the maiden on Pitts II

My Pitts probably won't begin to assemble for a month or so. But with all of your help and that of the others here on RCU it should be a beauty.

It's 22deg with 30mph winds and a dusting of fresh snow here, so our flying days are pretty much over. I am committed to flying every month with my video plane. but I'm gonna holdout for the nicer days.

One final comment about the cost of things in this illness (ie., hobby, sport, etc.). If things have to cost so much because there is "limited demand", how come the most expensive things are always on back order or out of stock?