Scale Wendell Hostetler 30% PA-28 Cherokee Build

[TonyHallo]

I was unsuccessful at building a timer circuit using a LM555 timer. Not sure why it did not work but I made 3 different ones with the same result. Not to worry as a timer is very easy in OpenTX and all it takes is one logical switch, the timer is adjustable to 0.1 sec so it's all good. I bought colored LED's to use with the lenses and each color operates a different voltage so I made voltage regulators for each using LM 317 adjustable regulators. Still need to come up with a headlight. Still plugging away at the wings. Have the wing tube sleeves epoxied in in, working on flap linkage.

 

[AKNick]

Hmmm wonder what went wrong with the circuit? That Open Tx is quite a neat concept.

 

[BalsaDust]

OpenTX is bada$$. Their Flight timer options is something I wish all radio manufacturers would adopt. On gas or nitro planes I still just us a basic timer but all of my electric planes I use the throttle % timer. For others that haven't seen it the speed at which the timer counts down is based off of the throttle stick position. So like my Twisted Hobbies Turbo Beaver my timer is set to 2:15. If I flew a flight wide open throttle the timer would take just that 2:15 to complete. But if I fly at half throttle then the timer will count down at half speed and would end up with a total flight time of around 3:30 and so on throughout the range of the throttle stick. Its great as it doesn't matter how hard or easy you fly the plane if you land when the timer goes off you will end up with the same amount of capacity left in the pack.

 

[TonyHallo]

I wonder too. It looked so good on paper but just didn't work as expected. If I had an Oscope I could check the it out. That's OK because with the OpenTX timer there will be fewer parts since I had planned a PWM switch anyway. The switch will be switched by the timer in the TX, so simple. The position lights are nice and bright with the 1/2 watt LED's.

 

[AKNick]

OpenTX is bada$$. Their Flight timer options is something I wish all radio manufacturers would adopt. On gas or nitro planes I still just us a basic timer but all of my electric planes I use the throttle % timer. For others that haven't seen it the speed at which the timer counts down is based off of the throttle stick position. So like my Twisted Hobbies Turbo Beaver my timer is set to 2:15. If I flew a flight wide open throttle the timer would take just that 2:15 to complete. But if I fly at half throttle then the timer will count down at half speed and would end up with a total flight time of around 3:30 and so on throughout the range of the throttle stick. Its great as it doesn't matter how hard or easy you fly the plane if you land when the timer goes off you will end up with the same amount of capacity left in the pack.

My Futaba 18SZ you can use a % timer as well. On my 75"Edge I had a Telemetry Sensor that counted mAh used, so after a few flights you'd adjust the usage warning so you don't over draw your battery pack.

 

[-Rick-]

OpenTX is bada$$. Their Flight timer options is something I wish all radio manufacturers would adopt. On gas or nitro planes I still just us a basic timer but all of my electric planes I use the throttle % timer. For others that haven't seen it the speed at which the timer counts down is based off of the throttle stick position. So like my Twisted Hobbies Turbo Beaver my timer is set to 2:15. If I flew a flight wide open throttle the timer would take just that 2:15 to complete. But if I fly at half throttle then the timer will count down at half speed and would end up with a total flight time of around 3:30 and so on throughout the range of the throttle stick. Its great as it doesn't matter how hard or easy you fly the plane if you land when the timer goes off you will end up with the same amount of capacity left in the pack.

Throttle % is still there in Frsky's OS ETHOS. I flew all this past summer using it and really enjoy it. ETHOS is almost up to speed now as OTX which I always used before.

 

[TonyHallo]

I follow the X20, Tandem & Ethos thread, pretty sure I read every post, last year I decided to buy a Taranis 2019 SE so I don't expect to ever use Ethos, not sure why I continue to follow the thread? Excluding the touch screen functionality, I can't believe that Ethos will ever do any more for me than OpenTX does.
Back to work! I had planned to glue the flap hinges in after covering but after looking things it was clear this would not work so here goes. I made the widget to hold the wing brackets while the epoxy cured. The widget registers against the trailing edge and locates the hinge pivot point, gets clamped in place and the 1/8" brass pin locates the point. This was a slow process since one bracket was done at a time.
The flap was clamped into position and the two outside leaves were epoxied in. The center leaves will be done after covering. I'm pretty sure I can locate and cut the two squares in the Monokote, the third one may cause problems. The hinge pins are 1/8" brass tube with 2-56 machine screw

 

[TonyHallo]

I'm happy with the way hinges turned out. I plan to use the clevis from a DuBro HD adjustable control horn for the connection at the flap. This requires 3/16" thick material, thought about aircraft plywood but decided to order a 6" X 6" x 3/16" piece of G10 from McMaster Carr, should be here Monday. This plane is my first use of G10 and will use more in the future. Back to work on the left wing, just about reay to cut the flap free.

 

[TonyHallo]

Finally got to the point where the wires can run in the right wing. Using an eight pin Multiplex type connector that I picked up at the Toledo show years ago. Had these on the original Cherokee and they worked flawlessly for seven years. Found the circuit boards at Esprit Hobby, they work great. The ailerons, flaps and position light will consume all eight pins, the servo power is redundant since the outside pins are parallel top to bottom. The right wing is almost ready to complete the sheeting and I can get rid of the foam jig, yea!

 

[TonyHallo]

Got the final sheeting on the right wing yesterday and the top of the jig went to the curb last night, when I woke up this morning it was all but a memory! Helped my brother out at the auto shop yesterday and plan to return today so no work on the Cherokee