Table of Contents (to see the actual video links, scroll down):
Rene Caldera's (US) early micro-hybrid video (ca. 2000).
Rene Caldera’s (US) first three micro-hybrid flights (ca. 2000).
Gary Scroggs' (UK) mini-hybrid static test video (10/31/09).
Gary Scroggs' (UK) micro-hybrid static test video (11/1/09).
Jim Hefkey's (NZ) bi-hybrid static test video (12/23/11).
Jim Hefkey's (NZ) bi-hybrid flight video.
Dexter Labs (US) Whippet flight video (3/29/12).
Dexter Labs (US) WhipperSnapper flight video (3/29/12).
Dexter Labs (US) HTPB-fueled Bright Hawk flight video (4/12/13).
Dexter Labs (US) HTPB-fueled Whippet flight video (5/15/13).
Dexter Labs (US) 3-burn x 2 stage bi-hybrid static test video (3/5/14).
Dexter Labs (US) static test of a mini-hybrid burning a spent Estes C case (3/25/14).
Jesse Phillips' (US) on-board video of a Priority Stealth saucer flight (3/29/14).
Jesse Phillips' (US) on-board video of his "Snoodle" pool toy rocket flight (4/5/14).
Dexter Labs (US) 3-burn x 2 stage bi-hybrid flight test video (4/8/14).
Dexter Labs (US) 3-burn x 2 stage WhipperSnapper bi-hybrid flight video (10/27/15).
Dexter Labs (US) mini-hybrid HTPB grain static test (3/17/16).
Dexter Labs (US) mini-hybrid phenolic grain static test (3/17/16).
Dexter Labs (US) mini-hybrid phenolic grain flight test (4/6/16).
Dexter Labs (US) micro-hybrid flight to 1,042’ in an Estes Air Walker, my best single-stage micro (12/12/17).
Dexter Labs (US) mini-hybrid wax fireplace log grain (10/24/18).
Dexter Labs (US) 3x2 boosted mini bi-hybrid flight to 1,789’ on a modified Rookie airframe (12/24/18).
Dexter Labs (US) 29mm mini-max bi-hybrid test flight (4/15/19).
Dexter Labs (US) 29mm mini-max bi-hybrid CATO (4/25/19).
Dexter Labs (US) 3x2 boosted mini bi-hybrid flight to 2,100’ (est) on a 3F&NC airframe my best yet (10/17/19).
Gordon Strodel’s (US) micro-hybrid static test (11/22/19)
Gordon Strodel’s (US) micro-hybrid static test in slow motion (11/22/19)
Dexter Labs (US) mini-hybrid phenolic grain static test with an extremely long (55 second) burn (1/4/20).
Gordon Strodel’s (US) micro-hybrid powered flight of a Prime Stealth (6/9/20)
Gordon Strodel’s (US) micro-hybrid powered Prime Stealth launch in slow motion (6/9/20)
Dexter Labs (US) Whippet flying on a mini-hybrid burning poplar taken from an onboard camera (7/25/20).
Dexter Labs (US) Firestorm flying on a 3x2 boosted bi-hybrid mini taken from an onboard camera (8/22/20).
Christian Faix (DU) static firings of a number of 3D printed grains with star-patterned ports (5/15/21).
Matt Rolley (AU) Semi-static test firing of a micro-hybrid burning paper with a 0.031" injector (3/8/23).
Matt Rolley (AU) Semi-static test firing of a micro-hybrid burning Tasmanian Oak (3/8/23).
Matt Rolley (AU) Slo-mo liftoff of a micro-hybrid powered Mayfly rocket burning ABS (6/7/23).
Dexter Labs (US) Igniter/pre-heater grain test stand (6/14/23).
Matt Rolley (AU) flight of a long-case micro-hybrid powered Mayfly rocket burning ABS (8/18/23).
Actual video links and descriptions follow:
Rene Caldera's (US) video showing his early micro-hybrid static and flight tests (ca. 2000) (may be blocked by Warner Music Group):
Rene Caldera (US) operated a website from the late 1990s through the early 2000s. Here he sold kits of material along with instructions for machining your own micro-hybrid. On that website he had also posted videos of his first micro-hybrid flights. As a tribute to Rene’s inventiveness creating these small hybrids I am re-posting his three original flight videos. Along with the video I have also posted the flight report in Rene’s own words. Read the video “Description” to view the report.
Flight number one (3/26/00):
Flight number two (4/23/00):
Flight number three(2/11/01):
Gary Scroggs' (UK) 16 gram mini-hybrid motor in a static test using his custom polyester resin / iron oxide cast fuel grain. Look for his thrust curve data toward the end of the clip (10/31/09):
Gary Scroggs' (UK) 8 gram micro-hybrid motor in a static test using his custom polyester resin / iron oxide cast fuel grain. Look for his thrust curve data toward the end of the clip (11/1/09):
Jim Hefkey's (NZ) static tests with "bi-hybrid" gains. Here a live Estes C6-0 motor is used as a fuel grain for a micro-hybrid. The Estes motor burns as a "booster" then ignites the hybrid which in turn burns the spent cardboard casing (12/23/11):
One of Jim Hefkey's (NZ) bi-hybrid flight tests. Notice the "staging" is successful but the delay between the Estes burnout and the hybrid ignition is long and causes trajectory problems:
A Whippet rocket reaches 1,036 feet altitude powered by a Dexter Labs (US) mini-hybrid motor using a 16 gram charger and bag paper fuel grain. This represents a typical mini-hybrid flight (3/29/12):
A Dexter Labs (US) WhipperSnapper rocket flying on a micro-hybrid motor using an 8 gram charger and bag paper fuel grain reaches 650'. This is a fairly typical flight for this rocket and motor combination (3/29/12):
A modified Quest Bright Hawk rocket reaches 1,395 feet altitude powered by a Dexter Labs (US) mini-hybrid motor using a 16 gram charger and a fuel grain cast from HTPB/powdered aluminum (4/12/13):
A Dexter Labs (US) Whippet rocket lifts off powered by a mini-hybrid motor using a 16 gram charger and an HTPB / aluminum / lampblack fuel grain (5/15/13):
This is a static firing of "test article A" which is a mock-up of a three-burn by two-stage "bi-hybrid" rocket. The booster is a standard Estes D12-0 motor. At the end of its burn the D motor lights a modified Estes C6-0 motor loaded inside a Dexter Labs (US) micro-hybrid motor. At the end of its burn the C motor lights the hybrid which then burns the spent Estes paper case as fuel. See the publications available on this site for more details (3/5/14):
A Dexter Labs mini-hybrid burning the spent case of an Estes C class motor. This is the burn that would occur as the third burn of a 3 burn by 2 stage rocket configuration (3/25/14):
Take your Dramamine before viewing! Jesse Phillips (US) provided this interesting on-board video taken from his Priority Stealth flown on a Dexter Labs micro-hybrid with a poly-phenol fuel grain. The Priority Stealth is a triangular saucer-type craft designed by Art Applewhite that is built from a cut-up cardboard box (see www.artapplewhite.com). The Priority Stealth spins on ascent, flips over at apogee and auto-rotates while descending. It is highly recommended as a test vehicle for these small hybrids since the high drag keeps apogee low and the auto-rotated descent requires neither altimeter nor parachute. Try “pause-stepping” through the video to see the details of the flight including some surrounding buildings caught at apogee. Notice the serrated edge of the saucer skirt remains visible in the lower portion of the frame (3/29/14):
Jesse Phillips (US) on-board video of a Dexter Labs micro-hybrid powered Snoodle rocket. These types of rockets are made from foam pool noodle toys similar to those developed by Dick Stafford and others. This is another way to fly these small hybrid motors without the need for a deployment mechanism (4/15/14):
Successful flight of a 3 burn by 2 stage Dexter Labs (US) "bi-hybrid" micro-hybrid. In this flight a modified WhipperSnapper rocket is boosted with an Estes D12-0 motor. At burnout the booster ignites a modified Estes C6-0 motor grain contained within the combustion chamber of the micro-hybrid by direct staging. The C6-0 fuel burns supplying "cruising thrust" through the micro-hybrid's graphite nozzle. When the C6-0 grain burns out, the pre-heater grain is ignited, again by direct staging. The pre-heater grain starts the micro-hybrid which burns the paper case of the now-spent Estes motor as fuel. In all there are three separate burns contained in two physical stages. This flight was textbook with all burns completed successfully and with a vertical trajectory under calm conditions (peak altitude estimated at 1,500 feet). For more details see the User's Guide and Rocket Construction Manual (4/8/14):
Another very nice 3 burn by 2 stage flight of a Dexter Labs boosted WhipperSnapper rocket powered by a micro-hybrid motor. The boost is provided by an Estes D12-0 solid fuel motor and the sustainer is powered by a modified Estes C6-0 grain. The Estes motor has had its nozzle cut off and its diameter increased to fit snugly inside the Dexter Labs Micro-hybrid motor combustion chamber. This means that the hybrid burns once with the solid grain and once again with the nitrous oxidizer. The Estes grain is ignited via "direct staging" from the D-12 booster motor. At the end of its burn, the C6 motor ignites the hybrid pre-heater grain which melts the burst disc and starts the hybrid. The hybrid then burns the paper tube of the spent Estes C6-0 motor. The flashes seen late in the clip are from "flash panels" of automotive chrome trim tape wrapped around the body tube and also applied to the fins (10-27-15):
A Dexter Labs mini-hybrid burning an HTPB - aluminum - lampblack grain on a static test stand. You can see the 16 pound test stand actually jump a bit at peak thrust. The average thrust is around 11 N over a 2.5 second burn and peak trust showed 68 N on the test stand but the motor was not tight against the thrust ring and thus hammered the load cell a bit. Peak thrust was actually more like 40 N. Overall impulse is 27.2 N s (3/17/16):
A Dexter Labs mini-hybrid motor burning a grain made from XX paper phenolic tube. This fuel has rather interesting burn characteristics. The burn starts quickly as is typical for these small hybrid motors and peak thrust is reached smoothly with no hard start or ragged burn like for HTPB-based grains. Peak thrust is 31 N at 0.05 seconds into the burn. The depletion limb of the burn is very smooth and remarkably long, lasting 9.5 seconds with no chuffing before final flameout! Overall impulse is 24 N s (3/17/16):
A Dexter Labs Whippet rocket flying on a mini-hybrid motor powered by a paper phenolic grain reaching 700'. Since phenolic seems to burn long and slow I increased the injector orifice diameter from 0.025" to 0.028". A faster burn and greater peak thrust is the result (4/16/16):
This video shows the full flight (takeoff through recovery) of a lightweight version of a Dexter Labs micro-hybrid motor burning a poplar wood grain. This motor is flying in a modified Estes Air Walker airframe which reaches an altitude of 1,042 feet, my highest flying single stage micro-hybrid to date (flown on 12/12/17):
A nice dusk flight of a Dexter Labs 3” Boink rocket (pool noodle airframe) flying on a mini-hybrid motor burning a grain made from compressed artificial wax fireplace log material (10/24/18):
This is an updated and extended video to a brief one I posted showing this launch. Since it represents my first fully successful mini bi-hybrid flight and remains one of my best flights for this motor I have added the pre-flight “pibal” release, the complete flight from launch to touchdown and a clip of the recovery. "Traditional" bi-hybrid launches for the mini-hybrid motor are difficult to pull off because the launch weight is very heavy for the C6-0 motor to push from a dead start even with the recommended modifications presented in my manuals. Adding a D12-0 powered booster changes the whole picture. The D12 gets the entire system moving to 150 fps. While providing no additional acceleration, the C6 (in reality around a C9 after the drilling mods) keeps the velocity fairly constant and when the E mini-hybrid kicks in burning the case of the C motor things speed up again to 330 fps. This modified Rookie with its booster reached 1,789 feet in a 12 second ascent.
A Dexter Labs 29mm Mini-max bi-hybrid motor flying in a 3" Boink rocket (pool noodle airframe). The Mini-max is burning an Estes D12-0 motor. First the Estes burns its own black powder propellant then at the end of its burn the Estes starts the 16 gram mini-hybrid which burns the cardboard of the spent case (4/15/19):
A Dexter Labs 29mm Mini-max bi-hybrid motor flying in a 3" Boink rocket CATOs within its first 5 feet of flight. The Estes E12-0 motor used as the base grain was only slightly modified. It appears that the hybrid started early while the black powder was still burning but the root cause of the CATO is still unknown and is under study. I have come to learn that Estes E12 motors suffer high CATO rates! Until Estes resolves the problem (they are aware of the issue) I recommend using only the D12 version of the Mini-max motor. Notice that the fifty foot launch distance that I use for standard micro and mini-hybrids is not safe enough for these larger mini-max motors! (4/25/19):
This is a flight of a Dexter Labs 3F&NC superlight scratch-build airframe powered by a mini bi-hybrid motor and boosted by a D12-0 grain contained in a modified Estes Mongoose booster. This all produces a 3 burn by 2 stage flight with a total launch weight of 272 grams, 100 grams lighter than the two-stage Rookie flight shown above. This rocket was never recovered but based on comparisons of flight events from the Rookie flown to a known 1,789’ it is conservatively estimated that this 3F&NC flight reached over 2,100'. My best performance to date:
This is a static test firing of Gordon Strodel’s micro-hybrid burning an acrylic grain. The burn is classic for an acrylic grain with quick positive ignition, bright flame, and clean, smooth burn with no chuffing:
This is another view of Gordon’s micro-hybrid burning an acrylic grain as seen in the previous clip. This time the video is slowed down and has very sensitive audio so you can hear interesting details of the burn:
This is a static test of a mini-hybrid burning a phenolic grain that turned out completely unexpected. I have had long burns with phenolic before and that is one of the hallmarks of the material as a fuel but this burn is way longer than anything else I have ever experienced. Granted, it never produces over 1 newton of thrust but it burns for 55 seconds using only 16 grams of nitrous! Upon disassembly, the burst disk had only a pin hole but the pre-heater did ignite the main grain and the burn proceeds at a low level for almost a minute holding flame the whole time. To me, this emphasizes the variability possible with different burst disk melt characteristics and also the possibility of throttling this fuel type!
Gordon Strodel’s flight of a Prime Stealth saucer (Millennial’s version of Art Applewhite’s Priority Stealth) made from an Amazon box and powered by a micro-hybrid burning an acrylic grain. A very nice flight!
A slow motion video of the liftoff of Gordon Strodel’s Prime Stealth flight powered by a micro-hybrid burning an acrylic grain. The sound effects are very interesting and “big rocket” like!!
A wild ride onboard a Dexter Labs Whippet mini-hybrid powered rocket burning poplar wood for fuel. The burn lasts 5 seconds and the rocket reaches just under 1,200 feet. The video is taken with a Fuvision mini camera simply aimed out a side port in the payload bay. Hence the video is upside-down for the descent and I have rotated the second part in editing so everything appears heads-up. I think the whistling sound is nitrous still venting at the end of the burn (but it could be air flow across the video port) and the whistle transitions into a gurgling sound as the last traces of nitrous are vented. The wire-like object flashing across some of the frames is the spent deployment charge. Despite all the yelping sounds, no puppies were harmed during the creation of this video.
This is unedited video from the ascending portion of the flight of a modified Estes Firestorm and Booster 60 two stage airframe. This configuration is relatively low flying due to drag from the camera mirror pods extending beyond the 1.6 inch diameter body tube along with the additional mass of the video camera and bay. Booster ignition starts at 5 seconds into the video. About 1.5 seconds later the over-drilled D12-0 booster burns out and separates. Flames can be seen still issuing from the top of the booster airframe as it falls away. Virtually simultaneously the mini-hybrid comes to life by direct staging from the D12-0 and the C6-0 (actually a C9 or 10 after the modifications) black powder grain burns for another 1.5 seconds as indicated by the spiraling smoke trail following the upper stage as it develops a small wobble after separation. A few sparks are all that indicates the end of the C grain burn which has been spiked with a bit of pyrogen painted in the top of the case to carry the flame across the “gap” to the pre-heater grain. The pre-heater grain then burns for about a half second with no visible indication in the exhaust. A brief puff of smoke follows indicating ignition of the nitrous/paper third burn that lasts for about three more seconds. After a brief coast the deployment charge is detonated by the Altus Metrum Easy Mini altimeter at apogee and the parachute is seen being ejected. The video is obtained through a port in the side of the altimeter/camera bay and a 50 degree mirror affixed to an external pod adjacent to the port. You will notice that a “halo” of horizontal scenery surrounds the vertical view due to the camera seeing around the edges of the mirror pod. Video editing is needed to cut that away.
A nice set of test stand burn videos from Christian Faix in Germany for a couple of types of fuel grains I do not cover in my manual (ABS and HDPE) and the grains are 3D printed with star port patterns! Also he includes a Klima D9 black powder burn for reference (shown below left) which is nice since the Estes D and E motors are most often shown in the US for comparison. Note that his test stand is configured in a vertical thrust-down orientation which often leads to mostly gaseous N2O being burned producing long-tailed down-curving thrust curves as shown in his video.
Matt Rolley, one of my Australian motor customers, firing his micro-hybrid in a semi-static test where he uses his standard launch pad and a rocket as the test stand. By securing the pad against lifting and by capping the rail a few inches above the rocket he can observe and record the ability of the motor to lift the rocket, the speed and force with which the rocket lifts off, the duration of the lifting thrust, the full duration of the burn and the quality of the burn. All of this can be determined by time-stepping through frames of the resulting video! In this particular test Matt is using a standard paper grain but with an oversized injector (0.031”). Notice the lift is very strong and the burn is quite short (1.5 seconds) as to be expected from the oversized injector.
Another Matt Rolley semi-static test. In this particular test Matt is using a wooden grain made from Tasmanian Oak along with a standard sized injector for the micro (0.020”). The ignition is nice and quick for a small hybrid, the burn is vigorous with good lift (even causing the nose section to be forced off due to momentum) along with a nice shower of hot looking sparks that linger like welding sparks. The overall burn is 4 seconds long. I love that Tasmanian Oak for rocket fuel J
Slo-mo of Matt Rolley’s Mayfly rocket lifting off on a Dexter Labs micro-hybrid motor burning a 3D printed ABS grain with a spiraled star port. Great flight Matt!!
Igniter to pre-heater grain transition problems are the most common reasons these small hybrids fail to launch. Rather than waiting until you are at the range to evaluate the effectiveness of your igniter and pre-heater grain combo, I have come up with this simple test arrangement that fairly closely simulates the igniter/pre-heater contact during an actual launch. The stand consists of a base (block of wood) and vertical support (coat hanger wire, skewer etc.) to which the igniter is taped vertically. A short piece of 1/2" ID brass tube is used to hold the pre-heater grain at the tube top end. Place the tube/pre-heater grain over the igniter arrangement and fire when ready. If your igniters work consistently here you will have far better luck on the range!
Matt Rolley flying his Mayfly II rocket on a Dexter Labs long case micro-hybrid motor. This flight is fueled with one of Matt's great 3D printed ABS grains, a 12 point star with a 180 degree spiral twist down the length of the port. The N2O cartridge is a 9 gram Quick Whip injected through a 0.025" orifice jet. This burn is quick with without the long regressive tail typical of these small hybrids. The flame is bright flame, the smoke is dark and the sound is throaty.