Thread Tools
This thread is privately moderated by VicT, who may elect to delete unwanted replies.
Oct 11, 2019, 02:11 PM
Registered User
Thread OP
Discussion

Timber mods


When I first got my Timber I liked the articulated/hinged main landing gear with springs. I thought it would hold up to true dropped in hard landings and it did for about 20 landings. Then problems started to show up. Spring stretch, then spring limiter failure then splitting of the seam where the plastic landing gear mounts are located.

I called Horizon fixed wing technical and they gave me free landing gear and springs (when they were in stock). I installed the new parts and the same problems would re occur. This did not happen at the 2 clubs that I belong to that have hard runways. However I quickly learned that the Timber is a great trainer if the student and instructor can avoid nose overs and prop strikes. (Iíve been flying RC since 1965 and RC instructing since 1996 when I retired as a military C-130 instructor pilot)

I changed my landing style from STOL type touchdowns to conventional round out/flare type touchdowns and this helped but when landing in grass the added drag on the big wheels caused momentum problems where the Timber would nose over and the windmilling prop would strike the grass/ground. This did not help beginners learning the Timber and I ended up fixing many Timber landing gear problems until I switched to the Valiant 1.3 landing gear. It changed the looks but kept the Timber operational much longer than the stock articulated gear design. Here is how I tried to fix the articulated design problems.

I wanted to fix the design problem of the landing gear and so the first think I did was to install metal wire anchors into the plastic to limit and prevent fuselage and landing gear separation. I have a large selection of K and S music wire so I picked the smallest diameter and bent it into a U shape. (You might be able to use a large paper clip if itís straightened and is long enough). I used a 1 inch section of the wire and chucked it into my Dremmel drill and bore two holes into the plastic for the two U legs. I used CA and kicker to secure the wires and they have remained secure since. There is corrosion on the wires from my salt water float operations but no rusting and the wires keep the plastic parts from separation. The foam outside the plastic parts are still subjected to forces that can only be fixed by more elaborate landing gear designs like the Just Aircraft Super STOL oil filled shock absorbers. Iíve been trying to find a pair of 6-9 inch long oil filled shocks from the RC vehicle side but have not found them. I can make up spring type units using fuel tubing as a spring and shock absorber and could do that but it would not solve the nose over problem. I moved the axles forward about 2 inches using ply wood extensions and this helped but the spring stretching continued until I installed non stretching music wires and Dubro 4 inch inflatable tires. Kavan inflatables are more expensive and hard to get but are the best for bush style wheels and tires. They mitigate bounces and post bounce damage. I used the Wilga style gear (like Draco) but found the aluminum too weak. The pivot and spring design with no oil dampening did not help.

In the pic below you can see the two pieces of wire that keep the fuselage in tension and keep the plastic parts from separation.

Just below that is a partial shot of the Valiant 1.3 landing gear that I have put on 5 Timbers and one Turbo Timber. This solves the nose over problems and eliminates springs and fuse separation. The gear can be re bent multiple times for hard landings and can be hot glued in or bolted in place. The forward placement of the axles and lower center of mass mitigate nose over and prop strikes that lead to prop imbalance and eventual foam separation of the nose section inflight or on run up.

After replacing 4 or 5 servos on other Timber users I started to add a second elevator servo to act as a single elevator in case one servo failed to work or got stuck. You might be able to safely control and prevent a crash with total aileron or rudder failure but elevator failure is hard to land with out a crash. I did it once when an elevator clevis failed. Thanks to the flaps and SAFE I was able to use power to control the rate of descent to touchdown. Iíve since used a wire mod but using the Dubro black 1.3 nylon clevis with the 1/16 inch clevis pin is easier to do.

After that I started to convert the belly battery compartment into a top cowl battery compartment. Other mods are folding prop mod, split aileron motor glider mod, wing folding mod, see thru engine cowl, and 4S prop conversion.
Sign up now
to remove ads between posts


Quick Reply
Message:
Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Idea Possible Timber 1.5m mod? Bsteves Electric Plane Talk 11 Apr 04, 2017 01:36 PM
Discussion Timber Mod-Skis EPBDDSB Electric Plane Talk 2 Mar 06, 2017 03:39 PM