Greetings Amped up Flyers-

Background : My control line "restart" was with a Brodak Warbird profile acquired in an estate sale. I just flattened out the nose with my disc sander and grafted on a homemade fiberglass motor mount; mounting screws accessed from between the engine bearers. Although it flew great (until I crashed it) it had fundamental problems : 1) the motor (Neumotors 1905) is heavier than the designed for Fox 35 and 2) my chosen 4S2700 Lipo packs are longer than the space for the gas tank in the model. To balance it properly, the battery pack needs to extend past the wing L.E. by an inch which along with all the guts hanging out looked lousy.

Since I have a brand new Brodak Warbird profile kit and in need of a new airplane, I thought I would do something about it to neatly accommodate the guts and adhere to the usual R/C convention battery mount using velcro longitudinal shear pad and velcro wrap around strap. I have (2) other R/C models that use the same set of batteries so this is the best way to make good use of them.

So far, my Sea Hurricane Semi-Scale Stunt model (profile) has the wing framed up which is required in order to interface the modified fuselage nose to it. I am now designing the fuselage structural modifications, central of which is a battery mount plate starting at the high point of the wing and extends forward to pick up the firewall. The 1/2 inch balsa formerly above this plate will be deleted and a "lost foam" fiberglass battery hatch fabricated. Haven't completely decided how to treat the under side of the plate as it is mostly just fairing. Maybe stringers, maybe more lost foam? Trying to keep it light. The 1/16th ply fuselage doublers are being replaced with 1/32 ply to save some weight. Here are a couple pics of the modified plans with the motor and battery shown in their final positions. I will bring you along as I implement the modifications so others may try it as well. 

Cheers,

Steve Manganelli

Ken, do you fly clockwise, or do you put the battery on the outside, held in place only by the straps?

I put the battery on so that it's getting pressed into its pocket -- then the strap could fail completely and the battery will stay in place.

I lost an outside mounted battery once.  The airplane came straight  down.  Took a new profile body to get it back in the air.  Battery is now on the inside.   Tip weight didn't change.  PS battery is researched.

Ken-

Yours is very pretty! I'm dead set on using batteries I already have and use on other models. That's why the orientation and mounting position are more or less defined for me. Shouldn't be an issue for centrifugal ejection, however beware vertical ejection! Did that on an R/C model, found the wreck but never the battery! CL model should get tail heavy but still controllable(?). The closer the battery pack is to the CG, the less the cornering inertia (maybe?). One lesson here is velcro is not forever! Degradation is slow : change it out periodically before something bad happens!

Thanks for the Encouragement,

Steve Manganelli

 CL model should get tail heavy but still controllable(?). The closer the battery pack is to the CG, the less the cornering inertia (maybe?). One lesson here is velcro is not forever! Degradation is slow : change it out periodically before something bad happens!

On the ejections I have experienced I was able to get the plane down.  I can't explain how. lucky I guess.  We sometimes forget that there is centrifugal force along several planes in a corner as well as inertia.  I change my straps periodically.  On built up fuselages I always use an inboard side hatch.  I will never use a top hatch unless it has a locking bar.

Ken

Ken

Ken-

I'm a little worried now! The R/Cs that use the same batteries have 1 velcro strap around the middle of the pack. In fact the one that failed and ejected the battery was in a roll maneuver with failing velcro (roll not possible in CL). Has anyone put a G-meter in a Stunter to measure the forces in various maneuvers? This will do it if no one else has done it :https://www.sparkfun.com/sparkfun-openlog-artemis.html An outside square would be bad, but that's not in the beginner pattern!

Cheers,

Steve Manganelli

I have read that a sharp corner generates about 10g.  That may be way off but there are folks on here that might now.  If you study the builds that are presented here you are not going to end up with a problem plane.

Ken