Progress Report: 8/17/09

We currently refining the design of our Ultimate 20-300s.  Rest assured, in keeping with our tradition of producing only the highest quality kits and best flying aircraft available, Carden Aircraft will offer production versions of our Ultimate when we have met our standard of excellence.  Currently, our plan is to make production versions of this exciting new kit available in 2010.

Stay tuned for more reports as the Ultimate progresses.

Prototype 1 Flight Report

Mike McConville and Frank Noll Jr. are dear old friends who took time from their busy schedules to help test fly the Carden Aircraft Ultimate 20-300s prototype. In total, ten of us met at Eli Field in Monticello, Illinois. Our thanks go out to everyone there that day. 

The first flight burned 40 ounces of gas in a new DA-150 with MTW 100 canister mufflers and a 3 blade prop. Dry flying weight was 39.4 pounds.

With Mike on the sticks, take off roll and climb out was smooth and powerful. The new bird was solid and tracked quite well with no pitch couple and only slight roll couple mix required. Flight testing included precision loops, rolls, snap rolls, rolling circles, sequence flying and 3-D. We were all pleased and excited with the superb flight performance of our new Ultimate. As the 50 ounce tank was getting low, Mike noticed that the plane began changing roll axis trim in the same direction of the roll. We all stood on the flight line speculating that the servo arms might be slipping on the servo output shaft splines. Since no one had noticed this before, Mike snapped and rolled the plane back and forth numerous times for all of us to witness this phenomena. A short while later, in a low G maneuver, the right wing panel flew off the cabane, right before our eyes! Frank said “keep it in knife edge”, and a moment later the right bottom wing departed. Within a few seconds, the left two panels went away and all that could be done was hold up elevator and wait for impact. The soft, rain soaked corn field helped absorb the energy. The fuse was broken in two and the four wing panels flew down range for what seemed to be forever. Dazed with disbelief, we took the long hike out and back. After setting the six component parts down, we cleaned two inches of mud off of our shoes in a large puddle. Here is an example of modelers and friends at their best! Good people haven’t changed a bit since I first started flying planes back in 59’. It’s what the hobby is really all about…worldwide…

SO WHAT HAPPENED?

Dr. Richard Held or Dr. Dick as I affectionately call him, returned home to Michigan with his brother Don and his broken plane. Dick handled things like the pro he is, and performed an autopsy  (crash analysis) the very next day. It appears that the side to side load on the cabane was too great, causing the top wing to shift side to side, two inches in each direction! Since the bottom wing was fixed to the fuselage, the cabane was forced to flex and the two interplane strut L-brackets bent over at a 30 degree angle. What’s amazing is the 1/8” thick aircraft aluminum brackets bent without pulling out the hard point mounts in the wings! This side to side movement of the top wing forced it to compress downward resulting in a compression fracture in the top main spar. Exactly when this occurred is hard to determine.

HOW DO WE FIX THIS?

We have learned a lot about the structure in crash analysis and believe we have identified the problem and have a workable fix. We will modify the cabane and inboard main spars.  The second prototype will be a quick turnaround build featuring a lightened CNC router cut motor box with similar design elements to our successful 126” Extra motor box. Other enhancements will include fewer parts with easier, lighter construction in those areas that were overbuilt. A dry flying weight of 37-38 pounds with a lighter pilot figure should be achievable. We hope to have the second prototype thoroughly flight tested with kit production beginning in 2010.

 Dennis

Call Carden Aircraft at 423-295-2295

See the Extra 330S here  | See the Edge 540 here

See the Extra 260 here | See the Yak 54 here

11/26/09