Ross Ohmen's Rocketry Obsession
38 mm Projects
Home
Model Rocketry History
The 99K Project
98mm Project - Level 3
54 mm Projects
38 mm Projects
29 mm Projects
24 mm Projects
13 - 18 mm Projects
My Launches - 2008
My Launches - 2007
My Launches - 2006
My Launches - 2005
My Launches - 2003-2004
Related Links
Contact Me

Here's some of my mid-power projects.  Note that 38mm is the BIGGEST motor these rockets can handle.

 
Original "Wahoo" - 38mm Thurnderbolt minimum diameter series.
 
Features:
1) Giant Leap 38mm fiberglass body tubes (or 38mm phenolic)
2) Perfectflight MAWD controlling dual deployment
3) Acme fin can
4) Aeropack engine retainer
 
History:
02/18/04 - Fresno - Flew on a Aerotech H123 for the first flight. It took off spectacularly, went up, arched over (no ejection!), fell past the main deploy, (no ejection!), and slammed into the ground, burying 3 1/2 feet of the rocket, and breaking off the back 1 foot with the fin can and motor. DANG!!
 
Borrowed a shovel, and started digging. An hour later, I had it back, and a hole that went up to my hips. Diagnosis revealed that I had drilled a hole in a capacitor of the MAWD as I was assembling the electronics bay. Let's just say that "that dog won't hunt", and let it go at that. SO...
 
Repaired the MAWD (new capacitor shipped to me, and soldered in). Don't trust it - new MAWD. Replaced most of the body tubes, and repaired the one with the fin can and engine retainer. Filled and sanded and filled and sanded, and finally painted the rocket a sweet red color.
 
07/18/04 - Fresno -  Put rocket on the pad and turned on the electronics. Wrong "main deploy" altitude, and what's that extra beeping? Pulled it off and disassembled. Reset "main deploy" altitude, and verified extra beeping - just arming tones. Not low battery. Turned off, and went back to pad. Loaded. Launched. Spectacular flight on I211. So spectacular, it disappeared. <<SUDDEN THOUGHT>> I DIDN'T TURN ON THE ELECTRONICS. <insert many obscenities here...> So, it's going to lawn-dart again. That is if I can find it. I hiked that plowed field for an hour - no sign of it. Hunted from my car with binoculars - no sign of it. IT'S GONE. All that effort and hardware - gone. At least my contact information is on it, so if someone ever finds the fins sticking out of the ground...
 
Lessons: 1) Checkoff lists. 2) If you have a Walston unit, use it. 3) Get help spotting. 4) Paint your rockets flourescent colors. 5) Turn on the electronics. 6) Be happy.
 
Build two more - they're cool!  I've got the tubes already!
 
10/18/04 - Message from another rocketeer - they found my rocket!!!  Retrieve and salvage what's usable.
 
08/02/05 - Well, not much was salvable (of the body), but the electronics are good, and the motor case was fine as well.  The rear body will become another one of these (shortened to single deploy), and the recovery stuff will go in others of the series.
 
STATUS:  Salvaged
 
On the pad, ready to fly for the first flight.

thunderbolt_38-0402-on_pad.jpg 

Lift off on the H123
thunderbolt_38-0402-lift_off.jpg

Airframe buried 3 1/2 feet in the soil!
thunderbolt_38-0402-nose_buried.jpg

Tail broken off after "lawn-darting"
thunderbolt_38-0402-tail_broken.jpg

 

Thunderbolt on I161 at TCC 07/18/04
38mm_thunderbolt_040718_in_flight.jpg

Replacement "Wahoo" - 38mm Thurnderbolt minimum diameter series.
 
2/11/06 - Flew at Snow Ranch on an H73 - slow liftoff and easy to track to about a thousand feet.  Looked like the main deployed at apogee, and the forward body tube separated at the wrong place.  I'm just happy to get it back in one piece.
 
5/6/06 - Flew at Snow Ranch again, this time on an I357 - Great flight!  (Except I forgot to untie the main, and it came in hard.)  Located with Walston - little damage!  Fly it again on something bigger!  Make the small-finned cousin!  Fly the paper-tube version!  (Adding a small 'chute to be a drogue).  Note that the rocket spun as it tumbled, and made a mess of the shock cord.
 
08/06/06 - Flew Wahoo again, this time at Aeronaut, on an I300 4-grain.  Great, fast flight.  Disappeared at launch, and found on the ground, 1/2 mile away.  Dual Deploy worked as expected, and the rocket went 5159 feet up!
 
05/18/07 - Flew the fiberglass version ("Wahoo") at Dairy Aire on an H999.  Dang that was violent!  That rocket up and disappeared.  Caught sight of the smoke trail, really high and arching over.   Lost sight of it.  Others pointed it out, on the chute, and it landed beautifully.  Went 3800'!
 
09/15/07 - XPRS - Flew the f/g version ("Wahoo") on a J350.  Awesome, fast, straight-outta-sight flight.  Heard it loud and clear on the Walston, but didn't get a visual.  Dave R and I went out for a look, but I had to turn back to LCO.  Dave found it minutes later - 8500' says the Perfectflite!!
 
04/05/08 - Snow Ranch - Flew the Wahoo on an I211, for (my) coolest flight of the day.  Had to recycle and old, home-made igniter, before the I lit, and it ripped the rocket off the pad.  It threw a slight turn, and headed north, and out of sight.  The Walston had a strong tone, which got stronger suddenly, signalling apogee ejection.  (That's a relief.)  No one saw it.  Had a good, strong, signal for a minute, which suddenly cut off.  Gotta be over that hill.  Started hiking.  Went around the hill, and got a "weak" signal across the meadow.  Hiked there.  Now I'm getting a slightly stronger signal 90 degrees away, up the valley (that would be called a "reflection").  Continued hiking and following.  Getting stronger, but the attenuator still kills it.  Kept pursuing.  Spotted it further up the valley.  Great!  Recovered without damage  The altitude?  5271 ft.  That's a new Mile-High Wall record.  Extremly cool!!!!  And I got my exercise hiking back.

Wahoo - 2 pounds of fiberglass fun
wahoo_reduced.jpg

Tang (above) and Wahoo (below)
tang_and_wahoo_reduced.jpg

 
Phenolic version - "Tang" - 38mm Thurnderbolt minimum diameter series.
 
02/18/07 - Flew the phenolic version ("Tang") on a G67R, with the dual deploy, and the shortened fins (removed 1" with the table saw).  Flew fine - straight up.  Deployed the streamer at apogee (and shredded the mylar), and tried to deploy the main at 300'.  No dice - chute didn't clear the tube, and it came in hard.  Rats.  No damage, though.
 
04/07/07 - Flew the phenolic version ("Tang") on an H73 at Snow Ranch.  Rocket weathercocked greatly, and didn't separate at apogee!  300' deploy ripped off the 'chute, zippered the forward BT, and separated 1/4" tubular nylon.  Talk about violent!  Thankfully, I found all the parts, and there was no other damage.
 
08/03/07 - Flew the Paper version ("Tang") at Aeronaut on a G339.  Fast liftoff, and easy coast to 1000'.  The MAWD ejected on time, and the streamer flapped to 300', where the main came out.  Perfect flight!
 
10/20/07 - October Skies - Flew the Tang at October Skies on an H242.  Fast, cool flight - good visuals through main deploy.  Separation!!  Can't believe it - just burned right through the shock cord.  Had to walk the alfalfa for a while, but eventually found it, minus the nose cone.  Rats!  Small tear/crack in the upper body, and a neatly parted shock cord.  Gotta protect it better, and/or use less BP.  Someone turned in the nose and main chute, so it can be rebuilt.  Altimeter says 2992 feet - high!!!

Tang - Acme fin can and phenolic - no f/g
tang_reduced.jpg

 

PML Io
 
   One of my work-horses.  I've flown this rocket on F, G, H, and even I engines, and it keeps together.
 
06/20/03 - Mudrock, with Aeropac.  I flew the PML Io on an F50-6, a G40-7, and a G80-7.  Worked fine!
 
09/20/03 - XPRS with AeroPac - Flew the Io on H210R - fine flight.
 
12/27/03 - Mojave Desert Area Rocketry at Aeriel Acres - Flew the Io on an H242 -  38mm.  Very fast and high - great flight!
 
07/17/04 - Flew the Io on Econojet G35-7 at TCC Fresno.  "Bang!"  Cato'ing motor blew out aft retainer.  What a mess.
 
09/12/04 - Fresno - Flew repaired PML Io on a G80-7.  Great flight, though it looked like the chute came out early.  No damage, though.  Tough rocket!
 
07/17/05 - Flew the Io on an 29/180 H128 to a high, screaming flight.  Took forever to come down on the parachute.  There was light damage from the high-speed flight: The PML sticker had peeled back, the return-address was hanging on by a thread, and there were many cracks near the base of one of the fins.  All this adds up to a rocket saying "This much and NO MORE".
 
05/06/08 - With Lunar at Snow Ranch - Flew the Io on a G40-7 - Great flight.
 
08/04/06 - With Aeropac at Aeronaut - Flew the Io on F22-7J - Too low!  Almost too long a delay...
 
09/22/06 - XPRS - Flew the Io on an H73 - Great, high, flight.
 
03/03/07 - Flew the Io on a G64-7 at Snow Ranch - great flight that landed close.
 
04/21/07 - Flew the Io on a G77R at TCC - another great flight.
 
08/03/07 - Aeronaut with Aeropac - Flew on an H123 - Great, high flight.
 
09/15/07 - Flew the Io on a Cesaroni I212 - the biggest motor this rocket has ever seen.  The rocket tore into the sky, and turned into a speck - but recovered successfully!
 
10/20/07 - October Skies - Flew on a G61W - good motor for a windy day.
 
11/18/07 - Thanksgiving launch at Fresno - Flew on a G67R for a good flight.
 
02/09/08 - Flew at Snow Ranch on a G61W-M, built by Jason.  Great flight, and nearby recovery.
 
05/16/08 - Dairy Aire, 2008.  Karl B offered me a G76G-10, and I said "sure!".  Ripped off the pad, and deployed right in front of the sun.  I never had eyeballs on it, but I had a Walston in it.  Recovered at the end of the flight line in good shape.

PML Io on H128 at Fresno 050717
pml_io_on_h128_at_fresno_050717.jpg