Schipmunk:

You are very right, when changing to a gas engine it's like learning all over again. In fact when I did my first 33% plane, it was a real learning experience. Everything I knew about building and wiring .40, .60 & 1.20's was thrown right out the window. The big birds don't use your regular control horns & clevises and rods. They use ball bearings, rocket city horns and titanium turn buckle rods. Servos get ganged together and need to be adjusted so as not to fight each other, etc, etc. Bigger batteries and regulators need to be used, etc, etc...Yes, it's a whole new world.

But, I found with the GP Patty Extra, changing any of the parts they give you in the ARF is a personal preference thing and type of flying your going to do with it. Everything they give you will work fine and be strong enough, except the tail wheel. After about 20+ flights it was a mess and I changed to a Ohio tailwheel setup. Don't get me wrong, the tail wheel they give you is OK, but not great. It will work on grass or pavement, but it just doesn't hold up and the wheel itself is a bit too small. Best to change it as your building so you don't have to do it later. And use at least a 1&1/4 inch wheel. I have a 1&1/2 inch on mine. Works fine and the Ohio tailwheel setup is very sturdy. Also (personal preference again) is to throw away those foam wheels they give you for the mains. Get some good Du-Bro feather lites or any brand with real rubber on it's wheel hub. I've always hated those foam things. (But it's a personal preference thing, other guys/gals love them.)

The HiTec digitals are fine. You didn't say which ones they where. The 56xx series is fine for the Patty, the 59xx series is over kill (IMO). Heck, myself and a lot of guys that fly 35-40% planes use the 59xx in these big planes. That's why I say the 59xx are over kill. The 56xx are a sport digital made for planes in the 80" range. They are cheaper but you still get tons of power and a good digital servo. (For your FYI, the 56xx uses a cored motor, the 59xx uses a coreless motor). In fact I would be using the HiTec 56xx in my Patty if it wasn't for the fact that I had five JR8101's hanging around and they where new. These (the JR 8101's are a 90oz in torque servo with wide spaced ball bearings and a coreless motor) are plenty strong enough for the Patty and (of course) why buy more when what you have will do. This hobby does get expensive!

Now, on to the subject of Pull-Pull with the BME50 up front. Your going to have a balance problem. The BME50 w/muffler is about 3.6 pounds. A little heaver than a big glow engine, but not by much. I found with the servos for the rudder in the tail (along with the elevator servos) that all I needed for balance was to move my battery packs around. I use a I4C Isolator so I have one 2400 mHa 4-cell pack on the servos and one 1100 mHa pack running just the receiver. (My 1400mHa ignition pack is mounted right next to the engine on the motor mount.) So figure I have the engine, the ignition & the ignition battery pack all on the motor mount, servos in the rear and all I did was move the 2400 & the 1100 pack a little behind the receiver/servo tray in the Patty and it balanced perfectly, by the book. Now I know a lot of guys did use Pull-Pull with their Patty, you may want to ask them or maybe they'll jump in here and help you out. All I know is if you where to use a Pull-Pull with the setup you've got planned your going to end up having to put some serious lead in the plane to make it balance. Then again, maybe not. The guys that have done it would give you better advice here than I can. If you look in ARF/ARC right here on RCU there's two huge threads on the building & flying of the GP Patty Extra. Both threads are excellent, just read through them and you'll probably find out what will be needed with the Pull-Pull and balance with the BME50. You can't miss these threads, thousands of replies and excellent advice. Lot's of pictures too.

Back to your last question (I'm rambling here)...the 2400 should be plenty enough for the receiver and servos. Even though I use a 2400 for servos and a 1100 on the Rx, I could eliminate the Isolator and just use the 2400 and be fine. You'll have enough power for five 10 minute flights before you'll need to charge and still have juice left (but always check your battery with a good volt meter and a load between flights to be safe, but after 20 years, I'm sure you know that).

I have to take my cowl off my Patty tonight for some maintenance. I'll snap a couple of pix and put them here by tomorrow for you. You'll be able to see the Bosch cap and the 4 wire hall sensor on the BME, etc...