My Upscale Estes Farside-X
During 2008 I decided to upscale the classic Estes Farside-X, a three-stage model rocket with a payload section larger than that found on the original Estes Farside. While calculating the dimensions
for the rocket, I settle upon BT-60 (1.637") for the main body tubes and BT-80H (2.64") for the payload section. This creates a 1.68 to 1 upscale of the original. Standard Estes 24mm black powder motors are the
propulsion. I dubbed her the -XXL for "Extra Extra Large"
The payload section is a wee bit smaller in diameter (.10") than it should be for a true upscale, but otherwise the rocket is very cool. I even canted the fins on the stages like the original
to get the effect of spin-stabilization on liftoff.
I finally got the nerve to fly her at the February 14, 2009 Rainbow Valley launch. I loaded up the boosters with D12-0s and put an E9-8 in the sustainer. Since this was an experimental design, I called
for a heads-up launch. Ignition was quick and the Farside-XXL slowly
lifted off the pad. This rocket was on the fence for the published 14-ounce maximum liftoff weight for the D12-0. I figured if it boosted straight enough to at least get through the first staging
event it should do pretty good from there.
Staging occured right on schedule with the rocket pointing straight up but at that moment something unexpected occured. The second stage ignited successfully but the sustainer also popped off the top
of the second stage! As the first booster fluttered to the ground, the second stage looped wildly around under full thrust and the sustainer quietly coasted to the top and then gracefully arced over and
came in ballistic right in front of the launch pads.
Almost immediately, I realized the flaw in my design. Because I was using gap staging, I had punched holes in the centering rings and tube couplers to allow the burn-through gasses an escape path. My mistake was
putting holes in the bottom and top centering rings of the middle stage. It effectively created a straight path for some of the gasses from the first staging event to bypass the 2nd stage, and the resulting pressure popped the
sustainer right off the top of the second stage.
I was able to recover all the components and surprisingly the rocket suffered very minimal damage. The first stage popped a fin and the second stage was undamaged. The ballistic impact of the sustainer shoved the nosecone most of the way into the payload section and dislodged the motor mount...the rest of the sustainer
was undamaged. I managed to remove the nosecone without further damage to the payload section and thankfully a new nosecone fit perfectly. The impact had stripped away the "shoulder" of the original nosecone, rendering
it unusable for the time being at least. The only other repair necessary was installing a centering ring in the 2nd stage over the one with holes in it.
Exactly one month later, I flew the repaired Farside-XXL again. D12-0s in the boosters and an E9-6 in the sustainer. I figured an eight-second delay was pushing it a bit and I didn't want to risk another
desert-dart. It was a bit breezy at Rainbow Valley on March 14, 2009 and once again I called for a heads-up launch. Again, the D12-0 ignited quickly and she weathercocked into the breeze a bit. At sustainer ignition,
she took a corkscrewing path to the north, away from the crowd line. Good thing I went with the E9-6 as she was well on the way down
when ejection occured. All parts were recovered successfully and the Farside-XXL lives to fly another day. Below is a sequence of photos from flight number two.
I flew the Farside-XXL again on November 14, 2009 at Rainbow Valley and had a near perfect flight on a D12-0/D12-0/E9-4. However, again the rocket pitched over to the northeast and was well on the way down when the chute
ejected. I decided to remove the launch lug and replaced it with two rail buttons. I plan on flying the same motor configuration again in December 2009 off a long rail to see if it will fly straighter if it has
more chance to pick up speed while travelling up the rail.
December 12, 2009 rolled around and I flew the Farside XXL twice at our club launch. Both flights were off a 1010 rail and as expected were considerably straighter than off
a launch rod.
Below are some photos of the flights.
Great first flight off the 1010 rail. Motors were D12-0 / D12-0 / E9-4. Both boosters stuck the landing near the pads...an indication of how straight up the boost was.
2nd flight was just as nice, especially with the actual rainbow in the background during launch. Motors were D12-0 / D12-0 / E9-6. The 2nd stage didn't fare so well on this flight as two fins were snapped
on impact. This photo does however show the rail buttons I used to replace the original launch lug.
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