u/electricitycat977

Hi everyone, as promised here is some footage from the first flight attempt for my Guillows Javelin rc conversion. The flight ended up rather short as the aircraft ended up gliding onto the ground. I think the issue is that I hesitated and did not throttle up and raise the elevator in time. I am considering adding some incidence on the main wing and adjusting the cg, but I would appreciate any other recommendations on how to make the next flight better. I have been wondering if it would be a good idea to remove the propeller and start controlling the aircraft as a glider before trying another powered flight.

Quick update from my prior posts. One of the hobby stores local to where I live had a propeller from the sport cub S RC airplane, which is where the gearbox on the nose originally came from. The propeller fit perfectly and the thrust is enough to give a noticeable pull when holding the aircraft by hand. I also tried suspending the model with a wire, and it looks like the control surfaces are large enough to change the pitch and yaw of the aircraft using the airflow from the propeller. Given that the model was successfully balanced on the metal pins on the wingtips, I think the only thing preventing a flight is the need to find a battery charger with a plug compatible with the small 1S batteries I have. Will update on how the first flight goes.

Thanks for all the help everyone, it has been a long journey to get this far.

Hi fellas

Given the progress on the tail surfaces, I decided today to balancing and the model and start considering which of these two propellers I should use. I am not sure if I should go with the red propeller that came with the free flight kit, or go with the black three blade that was recommended to me at the hobby store local to where I live. My intuition is that the black propeller would be more optimal given that the motor will probably turn the prop at a much higher speed that the original rubber band power plant could, but I would appreciate some input if my intuition is correct or not.

Thanks for your help everyone.

Hi everyone,

To update all of you on my progress so far, I followed through with a suggestion made on the post I made yesterday about the asymmetric control throw. It looks like moving the control cable to a different hole on the servo motor horn allowed the rudder deflection to become more symmetric. I am wondering if the amount of throw on the rudder seen in the video can be considered sufficient for control.

Hi Everyone.

I was able to glue the rudder and elevator in place and fix the issue with the control cables binding up inside the fuselage. I am still having some issues though with the rudder wanting to deflect more on side than the other. Do you fellas think that the rudder is still able to deflect enough to both sides such that the model can be controlled in flight? I am also wondering if the elevator deflection is sufficient to control the pitch of the aircraft.

If the control cable for the rudder needs to be fixed to reduce the issue of asymmetrical deflection, is it possible to use solder to splice in an extra section into the control cable? I mainly ask this because threading the metal cable through the fuselage and into the holes on the control horns is a tedious process for me, and I would appreciate an alternative if possible.

Thanks for all the help

Hi fellas,

I have been assembling a rudder and elevator for a balsa wood plane, with the hope of eventually converting it to RC. I have been sanding down the region where the two pieces meet down to bare balsa. I am wondering if I have sanded down the the rudder and elevator assembly sufficiently for wood glue to form a strong bond between the two pieces. I have been having problems getting the rudder and elevator to stick in my prior builds, and I would appreciate feedback about my work so far.

Thanks for the advice everyone.

Hi fellas,

I have been assembling a rudder and elevator for a Guillows Javelin, with the hope of eventually converting it to RC. I have been sanding down the region where the two pieces meet down to bare balsa. I am wondering if I have sanded down the the rudder and elevator assembly sufficiently for wood glue to form a strong bond between the two pieces. I have been having problems getting the rudder and elevator to stick in my prior builds, and I would appreciate feedback about my work so far.

Thanks for the advice everyone.

Hi Everyone, I am trying to change the frequency range for the s parameter plot, but I am having some problems. I am trying to expand the range of frequencies that is covered on the x axis, preferably from 300 MHz to 700 MHz. I tried changing the frequency range settings under simulation, as well as searching through the history list and changing all the instances of the original frequency range in my history list steps. I am not sure why, but it seems not matter what I change the frequency range for the s parameter remains from 400 MHz to 600 MHz. Any further suggestions would be appreciated. I tried looking around for a similar question, but was not able to find anything similar.

Thanks for all your help everyone

Hi Everyone

I was originally thinking of putting this in as a comment, but it looks like comments allow for only one attachment at a time. Anyway, here are some photos from the unicycle club meetups previously posted on this sub, posted with permission from the club members. We all had a great time at these meetups, and we hope to continue providing opportunities for both beginners and experienced unicyclists alike.

Hi fellas,

I have an update on the yagi uda design. I was able to take the antenna to an empty parking lot and measure the s11 magnitude with my friends portable vna. It looks like the outdoor s11 magnitude measurements match up consistently with simulation, and I think this is a strong indication that the antenna is working. I plan to eventually test the antenna inside an anechoic chamber to measure the radiation pattern and verify against the sim results.

I appreciate the input on my prior post about other antenna designs that have even more bandwidth at similar operating frequencies. Even though other antenna designs have more bandwidth, I still hope to publish these results in a paper as they demonstrate that Yagi Uda antennas optimized for wider bandwidth can retain their optimized bandwidth as a physical prototype. The papers I have read have often presented computer optimized designs for yagi uda antenna with wider bandwidth than usual, but few of them seem to go as far as verifying these results with a physical prototype. I am wondering if anyone here uses any type of computer optimized antenna design for HAM radio experiments.

To answer a few other questions about in the prior post, the balun I used in the design is a tapered microstrip balun design meant to match to 50 ohms across a wide bandwidth of frequencies. In this design, I used an exponential taper to mate a trace that registers as 50 ohms when over a ground plane to a another trace that registers as 50 ohms when above another trace equal in width.

The realized gain plot provided in CST also accounts for the loss due to reflection at the sma connector. The antenna is excited using a waveguide port in the model, which is placed inside the model of the sma port, and can be seen in red inside the connector itself.

Thanks for the input

Hi fellow artists.

I am not sure if this is already a well known principle or not, but recently noticed a pattern while doing some CAD work that may have some use in drawing airplanes. I noticed that when I looked at a line surrounded by a circle from a perspective angle, the circle becomes an ellipse. It seems that a line perpendicular to the original line travels consistently travels through the inflection points on the ellipse, with the inflection points being the point where a particle traveling on the the elliptical curve changes direction from left to right or right to left. I tried this out on some pictures of planes I found online, and it seems to work pretty well for constructing a perpendicular line that can be used to draw the wings of the aircraft.

Draw a line down the fuselage of the aircraft, or where the fuselage is meant to be when starting from scratch.

Draw a circle centered on the line.

Use a skew tool to distort the circle until it looks like the circle is surrounding the line, which should result in the circle being turned into more of an elliptical shape.

Mark inflection points on ellipse.

Draw line through points.

This procedure seems to consistently produce lines that follow the same slope as the wings of the aircraft in the photos below.

I think this method can be used as a rough estimate of where the wings should be in a drawing of an airplane given the direction of the fuselage. I am wondering what fellow artists think. Is it common for artists to try and use geometry and mathematical methods to make their artwork look more accurate to real life?

TL DR Do people who draw airplanes use geometry and ellipses to figure out where the wings should go?

Hi everyone,

I learned recently one of my friends has a close relative that flew A-10 Warthog's for the USAF,and I decided to make this pattern for my friends birthday. I would appreciate input on how this turned out. Unfortunately the user who linked me this pattern has since deleted their account, but I appreciate the help anyway. This pattern can be found for free on cyberstitchers.com .

Hi Fellas,

I have been simulating an optimized Yagi uda antenna design in a electromagnetic equation solver called CST. I was able to optimize the design for a bandwidth of about 30MHZ relative to an S parameter value of -15 dB or 1.43 VSWR according to the calculator I linked below. I am wondering if 30 MHZ can be considered a wide bandwidth at an operating frequency of 436.4 MHZ. Does anyone here also think this antenna can be useful for communicating with satellites?

https://3roam.com/s11-to-vswr-calculator/

Thanks for all your input.

Hi fellas,

I started my journey of learning chinese about a month ago, and I have reached a stuck point I am unable to overcome. I have been particularly confused on the word Ta, as the hello chinese app I am using seems to use Ta interchangeably with the english words "she" and "he". I tried looking this up in some learning chinese textbooks my uncle sent me, and it seems to indicate Ta refers generally to she, her, or it. I am now even more confused, any help would be appreciated.

I read through some prior posts, and one explanation given is that "plural pronouns don't indicate genders in English", I am not quite sure what this means either. Is Ta able to represent gender neutral pronouns like "they" in English?

Thanks for your help

I was doing some house cleaning today and found this button on the floor. I am not sure what the symbol is supposed to mean or where this button came from. The symbol kind of reminds me of 3 crossed tuning forks.