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Archive for March, 2019
Posted by VicT | Mar 29, 2019 @ 10:36 PM | 2,605 Views
This applies to Turbo Timber and any other design that uses foam or some other type of material for flight control hinges.

A hinge that gets loose on any flight control surface will cause erratic control in flight. If the hinge fails and the flight control departs the model then a crash is most likely especially if it is the elevator.

My Turbo Timber showed failure of the plastic elevator hinge. It was easy to see when I removed the stab/elevator for maintenance. The elevator was easy to move up and down as viewed on it’s edge. Many use the same center mounted nylon hinge with or without a metal hinge pin to fix a loose hinge but there is a better method that originated back in the 40’s and 50’s and is a variant of the thread and needle used way back then. It’s called Tyvek paper hinges.

I use the Tyvek paper that is used on mailing envelopes. I lightly sand both sides with 220-320 grit sanding paper and cut to size. Using regular (not foam safe) CA I glue the hinges to the top and bottom of the elevator and stab. I use Monocote plastic backing to push the paper and glue on to the sanded foam and this prevents the CA from sticking to my fingers. You can paint the white paper or protect it with tape.
Posted by VicT | Mar 14, 2019 @ 01:38 AM | 3,691 Views
As an experiment I want to see how the TT would perform as a motorglider but still retain the sportplane qualities. I removed the stock landing gear and installed the Valiant 1.2 gear which saves about .7 oz but is about half the area drag. I installed the Aerostar 60 amp ESC and activated the prop brake. With 10/6 folding blades on a 55 mm B+B aluminum spinner and 2200 4S she pulls 33 amps and 470 watts. She pulls very strongly.

The flight test was successful and I am pleased with the performance of the folding prop and Valiant landing gear. There is enough thrust on the smaller prop to maintain full up elevator (in SAFE Self Level) and climb at a near vertical pitch angle. At 200-400 ft with the motor stopped and flaps retracted she has a much better L/D glide ratio. Driftdown times are increased so that with 2:42 minutes of power used there was a 9:21 flight. There was 45 percent remaining on the 3200 4S 40C Kinexsis lipo pack so total flight time can be extended. However the style of flying is different than most flyers in my club.

The motor glider uses the motor to climb and glide. The glide can be slow or fast depending upon thermal and lift activity. On my test flight it was around sunset so wind and lift was scarce. However on sunny days between 10-2 lift is usually enough to maintain altitude and depending upon wing loading increase or climb. I’ll be comparing her to more dedicated foamy motor gliders like my Conscendo, Calypso, Radian...Continue Reading
Posted by VicT | Mar 07, 2019 @ 10:27 PM | 3,127 Views
I’ve flown my Turbo Timber with 3S 2200 45C Admirals, 1500 4S CHNL 100 C cells and Turnigy Graphene 2200 75 C 4S cells. The performance on 4S is the most desirable but endurance is not as good as 3S. The Graphene was tested and started out at 90 percent charged. Flying consisted of 5 max power climbs to 300 ft. 5 inside loops. 15 aileron rolls and 5 takeoffs and landings. This took a little less than 5 minutes using the DX9 power on timer. Total flight time was about 7 minutes because of power off glide times. Capacity of the Graphene 4S pack started out at 90 percent and at the end of 5 minutes was measured at 31 percent remaining. So 90-31= 59 Percent in 5 minutes or 59/5=11.8 percent/minute. If flying were to stop at 15 percent remaining then a total of 90-15= 75 percent would be used. This would take about 75 %/ 11.8 %/min X = 6.35 minutes. A 3200 4S 40 C pack has been recommended by Horizon and will be tested for similar endurance time.
Posted by VicT | Mar 07, 2019 @ 07:37 PM | 3,128 Views
All dimensions in millimeters.
Posted by VicT | Mar 05, 2019 @ 10:11 PM | 3,363 Views
The 60 amp Aerostar has advantages over the stock Turbo Timber Eflite 50 amp ESC:
1. With an extra channel you can reverse the rotation of the motor/prop for reverse thrust during surface operations.
2. The brake can be programmed on to stop the prop from windmilling. This reduces drag but also allows the ESC to go into reverse. I have not been able to turn the brake on for the stock Eflite 50 amp ESC
3. The ESC is rated for 60 amps which might be needed for 4S and larger props

The Aerostar has two leads. The 3 wire lead gets plugged into the throttle channel 1 for the AR636 that came with my Turbo Timber (TT). The second lead gets plugged into channel 5 (gear channel) and switch C is programmed to say “Forward thrust” for position C0 and 1 and “Reverse Thrust” for position C2. I use F0,1,2 for low to high rates and expo. The flaps are on channel 6 (Aux 1) and SAFE Self Level is on Aux 2 or channel 6. Using the Digital Switch Setup I have programmed position B0 and 1 as Self Level On and B2 as Off. Switch C0 and C1 are programmed for forward thrust and C2 as reverse thrust. I have not programmed in any Flight Modes but may after a few test and trim flights....Continue Reading
Posted by VicT | Mar 04, 2019 @ 01:40 PM | 3,503 Views
Weather not too good now so made up some “nice to have mods” for SST. Based on experience with regular Timber.

For picking up the loaded model I’ve installed a retractable handle. It can be used to hoist the float plane in and out of the water/weeds/docking area. Also for hanging from the ceiling. Coat hanger and bends or wheel collars.

The folding wing storage and transport mod has been around since Orville folded his bicycle for Wilbah! Use an old necktie or parachute cord and bungee to keep the wings against and on top of the fuse. Be careful that the anti collision red strobe lense does not dent the trailing edge flaps. The Ace hardware folding step stool can be used to sit butt, stand on or invert SST for feeding Lipos to the belly.
Posted by VicT | Mar 04, 2019 @ 07:36 AM | 3,420 Views
Stock rudder linkage throws are good enough for 180 turn arounds. Nose lights are nice and bright! Here is a short video.
Posted by VicT | Mar 04, 2019 @ 01:20 AM | 3,792 Views
Stock 10BL 800 KV motor with 50 amp ESC and 3S 2200 and 4S 2200 Turnigy Graphene
11/7 3 blade prop
26 A, 256 watts, 45 A, 650 watts
With 10/8 5 blade Eflite Spitfire 1.2 prop
24 A, 235 watts, 50 A, 690 watts