Manufacturer: | Paper |
BRIEF:
Conversion o' a Currell Graphics 1/144 scale Soviet N-1 paper model t' fly on 24 mm motors. Arrr! T' plans are available at t' Currell Graphics website.
T' N-1 rocket was t' Soviet answer t' t' American Saturn V moon rocket o' t' 1960's. Aye aye! Aye aye! T' Soviet plans t' beat t' United States t' t' moon depended on t' enormous N-1 booster. Ahoy! Well, blow me down! T' N-1 was more complex than t' Saturn V in that it consisted o' five stages and a total o' 30 engines in t' first stage alone. Ahoy! T' complexity o' t' rocket translated into poor reliability. Avast! Begad! T' N-1 rocket failed all four times it flew. Well, ya bilge rat, blow me down! T' second launch in July 1969 was a spectacular failure as t' first stage engines shut down shortly after launch and t' resultin' explosion from t' fallin' rocket completely destroyed t' launch site. After t' final flight failure in 1972, arrr, t' remainin' unflown rockets were scrapped and t' Soviets abandoned their human lunar ambitions.
TOOLS:
PARTS
MODIFICATIONS:
This review will only document t' changes required t' build a flyin' model.
T' N-1 paper model consists o' two sets o' parts and instructions. Ya scallywag! Avast! T' first set is for t' first stage (with a Soviet designation o' Block-A) containin' nine parts pages and five pages o' instructions. Avast, me proud beauty! T' second set builds t' upper stages and contains six part pages and six instruction pages. Begad! All aspects o' t' card model are outstanding. T' instructions are excellent in detail and clearly show how t' parts are assembled. Begad! T' parts print crisply and t' fit is perfect.
Construction o' t' model begins with t' first stage. All first stage parts were printed on 65 lb cardstock. Ahoy! T' first stage skin segments were built as specified in t' plans. Arrr! A hole be cut in t' center o' t' base plate t' allow a 24 mm mount t' be placed betwixt t' eight inner engines o' t' N-1 first stage.
Figure 1. Avast, me proud beauty! Avast, me bucko, me proud beauty! Completed First stage baseplate with hole cut for t' 24 mm motor tube.
T' 24 mm motor tube was glued into a BT-60 chute tube usin' home made centerin' rings. Ya scallywag! T' former rings used t' stiffen t' outer skin o' t' rocket were reinforced with poster board. Ya scallywag! Ya scallywag! T' holes cut in t' former rings were sized t' hold t' BT-60 tubing. Arrr! A hole for an internal launch lug was also cut in t' formers.
Figure 2. First stage chute tube with internal launch lug.
T' upper tank segments o' t' first stage were modified t' accommodate t' ejection o' t' parachute. Well, blow me down! Ya scallywag! I chose t' separate t' model at t' first/second stage split. Well, blow me down! Ahoy! T' first stage contains all t' recovery equipment. Arrr! A coupler was glued t' t' upper fuel tank segments. Avast! A screw eye was glued t' t' coupler t' attach a shock cord and parachute.
Figure 3. Well, blow me down! First stage fuel tank segment attached t' second stage by trusswork. Note coupler.
T' first and second stages o' t' N-1 rocket were connected by an interstage trusswork. Avast, me proud beauty! I glued t' trusswork directly t' t' upper tank segments as opposed t' t' specified points marked on t' first stage body. This was required because o' t' recovery design. Arrr! A similar trusswork connects t' third stage t' t' second stage.
T' interstage trusses were built as per t' instructions, but were reinforced with CA glue. An internal former rin' be added t' t' trusses for additional stiffness. Arrr! At t' start o' t' project I anticipated t' strengthenin' o' t' trusses t' be t' most critical modification for t' model t' be a successful flyer. Ahoy! T' combination o' t' former rings and CA resulted in strong pieces that handled flight conditions.
Figure 4. Begad! Arrr! First stage truss detail lookin' forward t' t' aft end o' t' second stage. Avast, me proud beauty! Note former rin' with notch and hole cut for internal launch lug.
T' first stage stabilizer grids were glued t' t' model in t' stowed position. T' plans call for them t' be applied in t' deployed position, arrr, but it was decided they might nay withstand t' rigors o' launch/landin' in that configuration. Well, blow me down! Blimey! Blimey! T' stowed position be simpler t' implement and required fewer modifications.
T' upper stages were constructed essentially t' plan. Well, blow me down! T' internal former rings were reinforced similarly t' t' first stage. Begad! T' second/third stage interstage truss was reinforced with CA and a former rin' similarly t' t' first/second stage truss.
A hole be cut in t' base o' t' second stage t' allow for t' internal launch lug t' pass through. Ahoy! Great care should be taken t' ensure t' proper alignment betwixt t' first stage and t' upper stage launch lugs. Well, blow me down! Arrr! T' launch rod exited t' rocket approximately in t' middle o' t' second stage betwixt two o' t' fuel line fairings. Ahoy! I added an extra fairin' t' mask both t' lug and t' hole required for t' rod t' exit. With more thorough planning, arrr, t' rod could be planned t' exit t' model closer t' t' second/third stage connection. Aye aye! Begad! This would probably look better aesthetically than me model.
T' upper payload shroud be reinforced with an additional layer o' cardstock t' increase strength. Nose weight was added usin' a bolt, ya bilge rat, nut, matey, and several washers. Ahoy! Approximately 1.5 ounces o' nose weight be added t' t' model.
T' N-1 required t' application o' many exterior detail pieces. All o' these were added t' me flyin' model. T' detail pieces are time consumin' t' apply, but t' resultin' model looks more polished and complete.
Figure 5. Completed N-1 on t' pad and ready for launch.
Stability was checked usin' a swin' test. Begad! An Estes C11-3 was placed in t' model and prepared for flight conditions. Blimey! Ya scallywag! T' initial swin' test was nay encouraging. Ya scallywag! Ahoy! T' model flew tail first. Ahoy! Ya scallywag! More nose weight be added t' push t' CG forward t' t' base o' t' second stage fuel line fairings. Begad! T' model still flew tail first.
Figure 6. Arrr! Swin' test.
After consultin' t' folks on T' Rocketry Forum it be suggested I use t' VCP program t' check t' stability. Blimey! VCP uses t' Barrowman equations t' determine t' center o' pressure. Bein' a series o' transition segments, t' N-1 is an ideal candidate for these equations. Aye aye! Aye aye! VCP showed that t' model had approximately 5-6 cm o' static margin.
T' VCP file has been enclosed.
RECOVERY:
For recovery, a single red 24" mylar chute be attached t' a shock cord. A tri-fold mount was selected t' secure t' shock cord t' t' model. Ahoy! Well, blow me down! An Estes Saturn V like dual recovery be considered and rejected, but could be implemented.
FLIGHT:
Encouraged by t' VCP results flight day finally arrived. Blimey! Arrr! Blimey! Loaded with parachute, wadding, and motor t' model weighed approximately 7 ounces. Ya scallywag! Avast! Blimey! An Estes C11-3 was chosen for t' first flight.
After a short countdown t' N-1 took flight. Avast! Boost be arrow straight t' ~125 feet. Arrr! No stability issues were noted. Blimey! T' parachute deployed properly, but t' shock cord be burned through by t' ejection charge. T' first stage tumbled in ballistic but landed safely in tall grass with no damage. Avast, me proud beauty! Begad! T' shock cord mount may have been glued too close t' t' motor and t' waddin' did nay adequately block t' hot ejection particles.
T' upper stage came down safely on t' 24" mylar chute. Avast, me proud beauty! Ya scallywag! Blimey! There was some damage t' t' escape tower so t' Estes trapeze recovery method will be re-examined for future N-1 flights.
Figure 7. Liftoff o' t' N-1!
SUMMARY:
This first flight was considered a success. Arrr! It flew straight and did nay get destroyed. Avast! T' minor escape tower damage has been repaired. Avast, me proud beauty! Once t' shock cord has been replaced further flights o' t' N-1 will occur on Estes D12-3 motors.
This be a challengin' project that took three months from first cuttin' t' launch. Begad! It pushed me skills in many directions. Avast! Ahoy! Seein' t' N-1 soar o' t' pad and into t' air was definitely a gratifyin' feeling.
I want t' thank t' many people on T' Rocketry Forum who encouraged me or assisted me when I had questions. Many o' their ideas ended up in t' final product.
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Robert A. Morstadt (January 11, 2023)
Excellent project !