From 211db9b8214d295f2baef59d774baddcab6b1737 Mon Sep 17 00:00:00 2001 From: Bdale Garbee Date: Sat, 8 Sep 2018 16:03:14 -0600 Subject: [PATCH] update Meh page --- rockets/airframes/MehGaNuke/index.mdwn | 160 ++++++++++++++-------- rockets/airframes/MehGaNuke/mehganuke.ork | Bin 2807 -> 3544 bytes 2 files changed, 103 insertions(+), 57 deletions(-) diff --git a/rockets/airframes/MehGaNuke/index.mdwn b/rockets/airframes/MehGaNuke/index.mdwn index 129c347..0556f3c 100644 --- a/rockets/airframes/MehGaNuke/index.mdwn +++ b/rockets/airframes/MehGaNuke/index.mdwn @@ -11,16 +11,17 @@ Unfortunately, that airframe was one of many lost in the At a conference late in 2014, one of the founders of Woot approached Bdale to talk about the possibility of another sponsored rocket project for his new venture, -[A Mediocre Corporation](https://mediocre.com/) and its flagship site +[Mediocre Laboratories](https://mediocre.com/) and its flagship site [meh](http://meh.com). Bdale had already started thinking about building another "big-ass rocket" ... After giving it some serious thought, the goal became building something bigger than anything Bdale had built and flown before, but that would fit in with the -"mediocre" theme somehow. Most rocket folks start out flying "three fins and a nose -cone", so doing a simple rocket of that style seemed like a good starting -point. The coolest such rocket clan Garbee has ever built was undoubtedly +"mediocre" theme somehow. Most rocket folks start out flying "three fins +and a nose cone", so doing a simple rocket of that style seemed like a +good starting point. The coolest such rocket clan Garbee has ever built +was undoubtedly [Robert's first high-power airframe](http://gag.com/rockets/airframes/LilNuke/), a [LOC Precision](http://shop.locprecision.com/) [Lil' Nuke](http://shop.locprecision.com/product.sc?productId=114&categoryId=12) @@ -38,59 +39,73 @@ fly low and super crowd-pleasing on fast-burning M motors like the [CTI Pro98 M3400WT](http://pro38.com/products/pro98/motor.php) in a suitable adapter. To achieve sufficient stability on an O motor, the nose needs to be pretty -heavy. Simulation suggests that turning the nose out of solid pine would work -out just about perfectly. - -Because such a heavy nose cone will put significant compression load on the rest -of the airframe, we'll build internal structure to carry that load rather than -depending on the airframe material itself. Some quick back of the envelope -calculations suggest that 3 ribs made of cheap, common 1x2 pine lumber should -more than suffice. - -The fins will be fabricated from nominal 1/2 inch birch plywood, rounded, -vacuum-bagged with one layer of carbon fiber for stiffness and one layer of -fiberglass for surface preservation and strength. They will insert into fin -grooves cut in the forward and aft fin rings and interlocked with two -intermediate rings. All fin to ring joints will be augmented with chopped -fiber and/or glass fabric scraps. Once the fin can is fully assembled, an -extra layer of fin to fin glass across the airframe will be installed to -help keep the fin can together during landings. - -The airframe will be constructed from 12-inch concrete form tubing with the -inner and outer layers peeled, wrapped with two layers of 6oz fiberglass. A -section of airframe tubing wrapped with one glass layer will be slit and -closed down to form a coupler so the main airframe can be built in two pieces -to ease transportation and flight prep. - -Recovery will involve a 3-foot drogue parachute deployed by blowing the nose -cone off at apogee, and an ARRD will be used to release a 28-foot main chute -from a deployment bag. For high flights, a reasonable main deploy height for -traditional "dual deploy" recovery will be chosen. For lower flights, the -main will be deployed just long enough after apogee to permit the drogue to -re-orient the airframe, approximating the "main out at apogee" experience. - -A side-access electronics bay will be constructed in the valley between two -fins near the leading edge of the fins. Electronics will consist of one -each Altus Metrum [TeleMega](http://altusmetrum.org/TeleMega) and -[TeleMetrum](http://altusmetrum.org/TeleMetrum) boards. The TeleMega is -overkill, but I'm curious to see what the airframe rotation rates are like -in flight, and the gyros will capture that. Each will use a single 850mAh -LiPo battery, and rotary switches mounted in the airframe for on/off. Two -charge cups will be mounted on the forward ring of the fin can for apogee -deployment, and an ARRD will be mounted on the other side of the same ring -for main deployment. - -The main airframe tube will contain ribs and additional structure to carry -the load induced by the nose cone, and to direct apogee deployment gasses -around the main parachute deployment bag. - -Because the kinetic energy at ground impact even under the large main will -be fairly high, the ring at the aft end of the airframe will be doubled -to 1.5 inches thick for extra strength. - -The airframe will be set up with 1515-sized rail buttons, and use of -Terry Lee's launch trailer with 20 foot rail is assumed to ensure stability -for all flights. +heavy. Simulation suggested that turning the nose out of solid pine would work +out just about perfectly. And thanks to the fire, Bdale had some large pine +logs drying... but trying to turn a nose cone out of one of those was kind of a +disaster! So we ended up asking Dan at +[Python Rocketry](https://pythonrocketry.com/) +for help, and he delivered an outstanding nose cone for the project! + +Because such a heavy nose cone would put significant compression load on the +rest of the airframe, we took notes from Kevin Trojanowski's large rocket +group projects, and decided to build internal structure to carry that load +rather than depending on the airframe material itself. Some quick back of +the envelope calculations suggest that 3 ribs made of cheap, common 1x2 pine +lumber would more than suffice. + +For the airframe, we acquired a length of 12-inch concrete column form, +peeling the inner and outer layers to get rid of the waxy surfaces. The +tubes were then wrapped with two layers of 6oz fiberglass using West Systems +epoxy and peel-ply fabric to consolidate the fibers and make for a reasonably +smooth finish with minimal sanding. A section of airframe tubing was slit and +closed down to form a coupler at the front of the fin can, so the main +airframe can be separated to ease transportation and flight prep. + +The fins were fabricated from nominal 1/2 inch birch plywood with rounded +edges. They were inserted into fin grooves cut in the forward and aft +centering rings and interlocked with two intermediate rings for mechanical +strength. All rings were CNC cut from 3/4 inch birch plywood, except the +aft ring which was doubled by laminating two pieces of plywood to form a +1.5-inch-thick aft ring more likely to survive the kinetic energy of +landing. The epoxy used for all fin to ring joints (and most others in the +airframe) was augmented with West Systems 403 Microfibers, yielding very +strong yet light joints. Once the fin can was fully assembled, the fins +were laminated with laminated with one partial layer of 5.7oz 2x2 twill +carbon fiber for stiffness, and one layer of tip to tip 6oz fiberglass for +surface preservation and strength. + +Charge cups for primary and secondary black powder charges mount on the +top of the fin can forward ring where they are easy to load before adding +the main airframe tube to the stack. This ring also sports an ARRD +intended to release the main chute during descent. The main airframe tube +has 3 ribs epoxied to the inside of the skin that sit on the fin can forward +ring after assembly, and provide a bearing surface for the nose cone once it +is installed. In this way, the compressive load from the nose mass carries +down through the ribs into the fin can plywood stack, and no significant +load is carried by the aiframe tubing itself. The main airframe also has +a "baffle" between two of the ribs that causes the gas produced by the black +powder charges to flow up past the main parachute to blow off the nose cone. + +Because the nose ended up being really heavy after adding sufficient nose +weight to stabilize the airframe on big motors, recovery starts by blowing +off the nose at apogee and deploying 2 mil-surplus 5-foot parachutes on +a "V" harness. The main chute is a 28-foot man-rated mil-surplus chute in +a Giant Leap deployment bag, and the harness is fabricated from lots of REI +1-inch climbing strap (in bright purple, of course!) and a number of +different size stainless steel quick-links. + +A side-access electronics bay in the valley between two fins provides +space for two removeable "sleds", each holding an Altus Metrum +[TeleMega](http://altusmetrum.org/TeleMega). Each TeleMega has a single +dedicated 850mAh LiPo battery, and a rotary power switch mounted in the +airframe for on/off. Custom dipole antennas were designed and integrated +into the construction just inside the airframe skin to maximize telemetry +performance, with RG-188 teflon coax and SMA connectors to the flight +computers. + +The airframe is configured with two 1515-sized rail buttons, and is really +only considered safe to launch from Terry Lee's launch trailer with 20 feet +of very stiff 1515 rail. ## Design / Simulation File @@ -125,3 +140,34 @@ but there are several spots where more epoxy would have made me happier. Will compensate when wrapping the airframe tubes. Given how "thirsty" the cardboard is, I think the trick will just be to paint the tube with a thick layer of epoxy before starting to apply the glass, then be generous when wetting each layer. + +At this point, a lot of time passed, and the airframe wasn't completed until +early 2018! + + +## Photos + +All the photos and video I've collected associated with this project can +be found [here](https://thor.gag.com/index.php?/category/MehGaNuke). + +## Flight Log + +The first flight of this airframe was at the [Kloudbusters](http://kloudbusters.org/) +[Airfest 24](http://kloudbusters.org/airfest/) in Argonia, Kansas, USA, +on Saturday, 1 September 2018. The motor was a 6-inch "O" built by James +Russell using his well-known "Russell Red" formula. Due to a slightly larger +than optimal nozzle throat, the motor burn was a bit longer and average thrust +a bit lower than expected... but a side-effect was a 9-10 foot brilliant red +flame tail that was awesome to see! The rocket hit about Mach 0.6 on the way +to 8068 feet above ground, and was recovered safely. Weather-cocking due to +wind caused the airframe to have a residual speed at apogee of nearly 60 meters +per second, so not surprisingly there was some modest zippering of the top of +the airframe. It also seems clear that the ARRD failed to retain the deployment +bag, as the main chute deployed a few seconds after apogee. The stress at +deployment tore the strap off the deployment bag, and the deployment bag was not +recovered. Some minor re-design of the deployment sequence seems indicated +before future flights. All in all, though, this was an outstanding group effort, +a lovely flight, and a huge crowd-pleaser! + + + diff --git a/rockets/airframes/MehGaNuke/mehganuke.ork b/rockets/airframes/MehGaNuke/mehganuke.ork index fd916806f9f0f3d3a9ac8f53af07ae178725673f..ce860be8d730332f6f55cd80951b25ec3ca33e80 100644 GIT binary patch delta 3512 zcmV;p4M+0#71$dNP)h>@6aWYa2mt9-Ax)7E8-HAFbK|xV{_bCaQKz}PnTjGnkN_vL zIz4yNPIGs@`feuu3X!11If_vEV#odUU62yrM9P%yIQGSvNn$Q`K>)k^V0Qs({?}hO z5xSO18mjpG4K~a-NXDM>!+3T6CeMN?fAiPH*<5X9oG9;`%qr#yHk=9a5-Bp3oKG%+ z4_7{By)nPq}-cQ-(60Z7B#2Ba({&B z6W?-OZ(L7=_`dI1cq&K`OsOTslnY@^$5_YF z>T(=dV#&EH#02>=5P6iHPqHMJRmX`8WCErsv)ip)Y{akOCg03wZSq;ko90W<%vQyq zo3xbI)J&}8{%LQHUo>%Vh;>_U4}YbUN+rxlHi`SrKHp|*m~iO^$t}9b(@bs9ClEmw zAk#GXN>XgMQX~SV&}rC;FwRgSwF+!|f>w!?;CAK&Eu&oOKV}_?bRELLOv9Yd%0Ju9 zv%yy>aOx!Vnn`a|3nS>%j+9u8?%RKs~ttw8#?Dl+O5yPB--ft5XD6v5$h`fg- zMf!P%DR2Mt`OCZcY~NMq4Uvpj*?NHuVl&d5`+T-*YV&7+K;L2s>llO)Ak2JLQ@Sb? zV8?0|UQ4Y+{m{d(6&mkgXn!ySbH`WHI`$Q0iSWZbU5GqWU=;n4^Zr(nvG4oxuETu%LZQpO64#@qepzH3_U_i#8-u zY1G8EOrQQrtc3;#BbKPeo*Z2e;&)$(!t!rV4Bg8dXOWwMH3W@N4H2R+tz;Co&%UDIBclZ8mF>JRt zo;&tuZBrIz4S&UWc(-nBl(x<6(%!Yzp0cIrjoVv;%@1LZpMR(oL?`&fy@c>n_7ZHJ zzL(g~Y%lTrU5o>N+zG2`o&>^^4I6{EIBc@G3bzopZ&7?3srV?i`f?koTY0TF6|q&T zGTW>3$M!z9^N3&}(r!+#>KMQn>yY3lcwmza*jPAMBc zQd-iUm@d_C`W$8+uHpjVb^rm$1QXKpYBvmtHJrUo>I!HTtwp>ld8?;`qMIJ+si!2p zI2z}GocahTS^RRP)zl#LVbMyau!je}>zaYhe3J-l`Iw0%<${`?ZE~P$j4BxWz)zq3 z6z3p|OMlCC`2ILZ3~U4y+7(sPW-M0+$4o1U~Udzyr?-#K=Ye%v{s?Ef$?I{sfCY>g=trNT$o6iHwxcXAM0y(XL`H zWGWIBhv=*H)&OE^bvss5HePztBQ$Vr7YreA9Df0h=sGU*F*lcZq^3TCF`3g}zMh~g zQy)m&tt``EN6Vd$rL0lMn|CSV<4>d4U0~sv1RP^&`CR`X{>on-D6a46)OK6-QFnWqqoa2@z(E-DZZ_Ih>J|xJZojc>c6)MJirX@ zV+v(#8OP0YBIdO296$u!WazVi*&QZuB!BJdIXpT5ltgUh|5WHh4w1^ili{y>HqgIL z%z$+eV1_cL`z2^2lCk@!k3!x4uGHSN({Ea1etG-q;wSVr&B7qi9{vuA z*hj_DCQ!>_2P$*3cbz*|Cnj?v9FUXJ0YOg*daHsU^yE?h)2}Vd4p#Bfp%O%*GJnx< zl>O5kz=sJta-yl1HBo7r?%WNg4w)A06D?|wkbof;<0$^>8G~4^i~9@xzE(H)iq>(L zLki}>4G7vQlY(#+mgHJy>U>iA>JCsFOufq=MKY_AfoLr>NJA2*pR%{*dR444Z>Gxc!0=hbuEKlM26jg;GZcYoI>3Qf|XK&3g$q|GXW3yDy_+Ti_N{5m^r1FdUK zV>ZwuIKnu7(DjJZH_-cSp3gdVddOyZuu8`T^=3 zku<)l^WN&b$C2_K>_DzRq3Pk#`A+${mwrgYO&%3F?yiFd1wltyo}Nztv3$^lUzNp6 z%la4mCq^miwtuaCPbyhl{Y<~?A7Dro{jAD#BX37~FOo#vY(#uf(RBV> zwO1l4_QS@w_r#*gzZi4&sEZUk_Op&VC2D^~#WpB+XiL3amL6dducBQAr$g&ut_{U) zOY~UK{3eWjaV-@HsDH6m>2iz)Nl`T_jHoC9rwZuv)UuL1Vk=a`Li*&mN81VFmM4gseL}VLP@JX}*mgsyE zrlMI~gG3&THIv)o?w-!%caN3V92(R-h;$kbrZ3P&{JLL>^9eN_$KVr9yq1yj$}g5I zZa7Xs6rLv|S$nJVwjolgii7{(J+zEihBmlzuq z>$0J)7_Gysej7C$Q?pmbQa2I(Wf<1Ts&DYoPH6`4BSn>D1<@0KY#t=PAC6zsC|%sxjLijb~^qjt%faJMcmQHC?v{UNB@sHfzBPb*OUyFYGWnvfw?oJCJ<=z6^v%%y6wCfWZdC z_A?KU@PCs6*d_W~vVvKN?-0KJDAAFnLl)O2uc&ndwJ;-w)kQ5wFI+EbIfhMJs0E9B zP%|PnU|ScpAWwAJ0BSLlv;MFMP|_VLN}Gn|Jolu|H0aYNb;7N0=Z7i=3Mr|fr~JV53)I8IR@=JOar=Ww||P=%yezs16 zmTM4Q6&r}Q9C%3&t`xsl2^h5!vHlIzEZ^v#IMuhl6O^r!Jk5^6(g%@%cwy)IH%>*C z3GZ9+i?6x9-m}9a_uXS*n|0p@6aWYa2mnd3n?{ii8-H7EkJ~m9{=UD0&;d;XoMln(LTwjF z4lQua+ie5nGc8dTv6AScq}}*_{SEalS@PQ6G)>zzkc~B*p~#tM9u6sa_0yLmM)y=? zjHl}tSk+!2n)*Co>2Cd^$is#E;-}5citlMExPM3UR$0NStsq}el5??EK7ht;rGYI~ zGk=uL4MMBRMt+5hlq7WXjz)_eLGOz@x>}Z!s?q03LeqTnpMqp;QS39H#1!!mU0bTx&5W^9*Iv3VWHvHwEEmck@kaix`Tu=aTxvRzRRpt@qgS|P;Mu%{afj16yL zYN5LzmZdKO-?gy5wasnlD$8?va&^<8jvX$j>G}&Z@V1MsVQLFv*hCBT!0>;lea1S-6B43w`UE*!8Gw1bW+(pdl52AetZcbd!)TEGd%Jawxv3bhBa$ z4&3t;T$ok%Qks(;ZLS*B{3eABUb?o)9x5xIQJ4bl3!Bc~Lz|r60D!Fu+3zV41jagQ z*b|oKNKok#%TmxzPzq_FDQFuPRDXV1jx4f>!3Z=}TP>@v!{+7etwNTvEZSrV=XtbR z)|W$_gyd8(5+mu-wX!YZI|T(a%~*a|E0zJbRW=`)oModr>LI4-E{`@?)d6x^_ihfYjVNYb%!q8v{TCLZ~Mt@NWb3p=D zWE)cC99-94AL(TgFXDiTx?NMTr32c#k6W6L)MmS>U2)uvHRxv2W4-pyRS+0U8;)Vl zk3AJ%f+g65B+lr-wr=Qyf7zkGFW&Ot02Dcy6R)97^5-ZShcLK{?I@dDw$H$YC_ThHoqq#ZT{7%rexUcV zh#-5utLlYLHfKTNoaIG8H^AF+W+UmGSwLfQ*z_za!Gt=iSy)p&Y?{5r0g&7_9^1u` z(LOI=$Iajp|(>ycH zn#?&P&pZ{I-(8*!8|LfzWmmkMThfFwAxZjN(2NTj&99bjx(78?Fu%_ zCCSuD3hV$AlJgoi%$fBPZYUZX@OvsElI|+q_G+wFj`Y$k`hO&sr3J8;Jbw_I&$lv6 zJ;4+o>}Zy6+%WJwEwr3K(+M^L?2xVL5>xYG69H1m6Q$x50m*}hay!5IV0gCMoJEis zGVZPVu-Q4yKn<9%X-osC9zu`(rh>36-TSE1&pOTcdQR7g?}Wsrw&6mmgq|LndKl=w z9=f4#hvZDBe}8m5&Hg={?l|r@aQayXKNI&a&v*olIgv*Mhdq5PFmGr^1Wy_IMEwXz zjPDNTM#{olpZdBPdX@)32yL4{B6_yx1lZNK_{>PX12Ace&z~*`mL|^;9uJnLI-35q zgH;P_{=8(PC>Kkp754Gun9G&2Zoa6DU1+Ld+L~i_%YTYrsJ_Y(M&!H?Wc~8?V^CZ?m@~hxkmeu(t;NF3JBr%Xq7!ep^Igaw%#2CmnqHGuC)5+E~ zPnvd%zO9$avnvp^wU~lh30!hdbG}xpWUU#sr!?vQIHq|=4Z4g%Pc&z78V1;{c9lP~ zEq@gy7MpHQAVC1~{D_O7nR+Lfm^#}xx^j-q)kM}lP`dAycX__t7abe4kux;2zs2>S z3ZD)e+<#19H81bzz9at1@7XQmMQ&&c%HFse2(Y!@x0=x;v?!H?%qqB(2+Zy>Qz^Hk$uv^kI*Y<{Tu#d=mUEH<`%u@LT>2$;A(o}Vsrbe`CD@V zLu%zW?Or$bYtd^W1b;|K`lgl19dO&;n(#DWy>U0f@`=FaoJU{soT6608Re7U&07kV zYPz;L2=7>B!kDDHxIV-g$tILLpnrHniwOj+9#|TXdn#mvb*bGK4At^NK#Iv%S>*$p zO0y>$kEDG+09(4*jpO*WfrfKP-C*`c-3pJidAh4w7Fg?b-^n|R9pwSdnV--+;=v}{ zM?eFpc1bYmXZGX8f@hOtU2A6?{dk#e0|ww%`u=>VSg+);(&aD z67r?-#9A>d+flJ1h4(b(e#u|D8=*4q-^nz8(Fpk*8uvI9nhwP#ou4*|m<%{lMeVSby zRX1kJ7p&sx@}>M$NRwvL3ozaTN_md96hR*V#rS|=X7X2KR5DIh?5W6j%KVCVGWCdX zt}BnOERKfP5XIH9`!6ly=H~xUO9u#M+#o%13IG5AIRF4qO928D02BZS2nYa4v71I_ X+#o%13IG5AIg_LfE(WOz00000K(kC` -- 2.30.2