NOTE: Please read my comment following the last video.
Here is Utah Trike’s video on how to fix a flat tire on the front of a tadpole trike:
And here is another video produced by the Bicycleman dealership:
And here is a video produced by Trek on fixing a flat on the rear wheel …
One thing I have noticed as I have watched various instructional videos on fixing flats is that they never mention a very simple and sensible means of finding the cause of the leak. If the leak is caused from an external puncture that means that the object that penetrated the tire and caused the hole in the inner tube is either still in the tire or it has come back out of the tire. Obviously if it is still in the tire it is most important to remove it or else it will puncture new inner tubes regardless of how many times you replace the inner tube. The easiest way and most sure way of finding the object is to use the leaking inner tube. To do so you must pay close attention to the orientation of the inner tube in the tire. Removing the inner tube carefully notice which direction it was in the tire as well as it’s position as to rotation. Again, the easiest way to do all of this is to always place the valve stem in the same place when installing the inner tube. I always place it right where the tire logo or name is. That eliminates any error. Then all one needs to concern them self with is which side was up toward them when they removed the inner tube. Once the inner tube is removed simply inflate the inner tube enough to locate the hole where air is escaping. Once the location is found lay the inner tube on top of the tire the same way it came out so that you can use the hole to locate the area of the tire to look for a foreign object. The hole in the inner tube may match up with the tread of the tire or it may be on a sidewall of the tire … or it maybe on the rim. If it is on the rim look for a sharp spot … a spoke hole or bad rim tape (hardened or out of place or both). What I have shared here is just common sense but I am amazed that I have never seen or read of anybody doing this when talking about fixing flats. It makes the job so much easier, faster and foolproof. I would much rather be riding my trike than working on it. There is an old saying that goes something like this … “if you haven’t got time to do the job right the first time how will you have the time to do it over?” Yep, learn to do it right the first time and then you can …
ENJOY THE RIDE!
A FREE GIFT awaits you!
Tadpole Rider 
Matt Timm, the fellow in the Utah Trikes video clip, is a good man – very knowledgeable and helpful on the telephone if you ever need any assistance.