If you can't find a helper, you can make a simple holdback device. Take a straightened wire coathanger, leave a straight 8" and then bend two loops and then another 8" straight section. Now make another straight section about 6" long. You also need to rig a landing gear tailskid with a loop on the end. To use, push the looped device into ground 'til just loops are showing. Place plane tailskid between the loops. Attach a line to pin and extend to center of circle. Start plane, go to center of circle and when ready pull pin. Good luck, red