Public Missiles Nimbus

Public Missiles - Nimbus {Kit}

Contributed by Tyndall Epps

Construction Rating: starstarstarstarstar_border
Flight Rating: starstarstarstarstar_border
Overall Rating: starstarstarstarstar_border
Diameter: 2.10 inches
Length: 73.00 inches
Manufacturer: Public Missiles
Style: Sport

Rocket PicBrief:
T' Nimbus is a 54mm minimum diameter rocket from PML that is designed for extremely high altitudes. Blimey! PML claims that this rocket has reached over 13,000 on a K motor. It consists o' a phenolic airframe, arrr, arrr, PML's CPR 3000 dual recovery system , G10 fiberglass fins , and a plastic nosecone. Blimey! Avast, matey, me proud beauty! It has a 36" nylon main chute and a 144" nylon streamer for a drouge. Ya scallywag! Avast, arrr, me proud beauty! PML recommends that this kit be fiberglassed and they offer a fiberglassin' kit for this purpose.

Construction:
T' Nimbus is a very well engineered kit employin' PML's CPR 3000 recovery system. Begad! Begad! This is one o' t' best dual recovery systems I've seen and I have used t' design in me other rockets as well. Avast! For more information on t' design o' this system, visit PML's website.

T' instructions for this kit are very complete and easy t' follow. Blimey! Even a person with limited experience buildin' high power rockets should be able t' handle this kit. Drawings are included and are clear and easy t' understand.

T' parts o' this kit fit perfectly t' first time. Begad! I did nay have t' sand a single piece. Aye aye! Avast, me proud beauty! I built this kit straight from t' instructions with one exception. Begad! I had an accident while epoxyin' t' upper ejection tube into t' airframe, shiver me timbers, t' assembly dropped and t' airframe cracked and t' centerin' rin' set inside t' tube. Ahoy! Result-- I had t' order a new section o' 54mm tubin' from PML. Avast, me proud beauty! (by t' way I received it t' next day via priority mail). Arrr! Since this was a full 36" piece I decided t' use t' whole thin' instead o' cuttin' a 15" piece off. This resulted in a very tall rocket which is now probably over stable. Begad! Avast! I would nay recommend this as a modification. Begad! Although it flew perfectly on a Kosdon J280 in 15MPH winds I will probably cut it back t' t' designed length .

Alt PackageT' good features o' this kit are t' well fittin' parts, shiver me timbers, t' "dado slots" used for surface mountin' t' fins and t' design o' t' CPR 3000 system. Blimey! Begad! This be t' 3rd minimum diameter rocket that I have built and t' "dado slots" work great. Avast, me proud beauty! Avast, me proud beauty! They involve cuttin' slots about 1/4 t' 1/2 thru t' airframe and settin' t' fins in these slots. T' only change I make t' PML's instructions which tell you t' epoxy them in place is that I set t' fins with medium viscosity CA and then apply epoxy fillets t' t' joint. Begad! Ahoy! I have yet t' lose a fin. On me modified VB38 t' main chute separated and t' rocket came down very hard on just a streamer and thar be no damage t' t' fins.

T' remainder o' t' construction is very straight-forward and does nay need t' be discussed here.

One feature that I have nay mentioned be t' piston system used t' deploy t' main chute and drouge. Bein' new t' t' hobby I asked a lot o' questions at our launches at Whitakers N.C. Avast, me proud beauty! We have a lot o' very experienced people in this group and most o' them recommend leavin' t' pistons out. Ya scallywag! I started t' do just that but decided t' try them anyway. Ahoy! (the only piece o' advice that I have nay used). Blimey! Well, blow me down! T' result - T' pistons have worked great and I will probably keep usin' them . Avast! Like PML says in t' instructions-- Just make sure they slide freely. Ahoy! Ya scallywag! They should fall out when t' airframe is turned upside down.

Now for t' bad part. Begad! I hate PML's phenolic tubing. It is too brittle, me hearties, me bucko, hard t' cut without chipping, and has deeper than normal spirals t' fill. About t' only thin' I would use this stuff for is as a mandrel for fiberglassing. Ya scallywag! I am nay good at fiberglassin' so I use Hawk Mountain or Giant Leaps filament wound epoxy fiberglass tubin' for high stress applications. Avast, me proud beauty! My next project is goin' t' be an exact copy o' this kit usin' Giant Leap's 54mm tubin' and replacin' t' Nimbus fins with a 54mm Acme fin canister and flyin' on a K700.

Finishing:
Finishin' be done usin' basic finishin' techniques. I filled t' spirals with Elmers wood filler. Ahoy! Begad! It took three heavy coats but it worked. Ya scallywag! Arrr! I then applied two coats o' Krylon white primer and finished in with Krylon purple and Krylon brass colored metallic paint.

Construction Rating: 4 out o' 5

RRC2Flight:
So far I only have 1 flight on this bird. It was a perfect flight on a Kosdon J280. Avast! This was me Level 2 cert flight and it be very windy that day so I decided t' go with t' smaller J instead o' t' K185 that I had planned t' use. Blimey! Arrr! T' Kosdon pushed this lanky 5 lb plus (loaded) bird through a 15MPH wind straight as a arrow . Avast! Avast, me proud beauty! T' PML CoPilot made by Cannonball Works deployed t' streamer right after it arc'd over and t' main came out at about 400ft . Well, shiver me timbers, blow me down! Exactly as planned. Blimey! Blimey! T' rocket be recovered about several hundred yards away all laid out in a straight line.

Recovery SectionRecovery:
T' CPR 3000 works great as does t' PML CoPilot. Avast, me proud beauty! Well, blow me down! This altimeter is essentially t' same as t' RCC2 from Cannonball Works. T' instructions are easy t' follow , me bucko, me hearties, t' altimeter is easy t' prep and every flight has worked t' perfection. Ya scallywag! Avast! I also use this on me VB38 which I modified for dual recovery. Aye aye! With t' exception o' one flight in which I put too much BP in t' ejection charge a blew apart me homemade screw on coupler. Blimey! T' altimeter was in t' part that came down hard under streamer only. No damage and I have had a couple o' nice flights with it since then . Blimey! Includin' t' Nimbus flight.

Flight Rating: 5 out o' 5

Summary:
Great lookin' kit . Avast! Arrr! Get rid o' t' phenolic tubing. CPR 3000 be t' best, easiest t' use dual recovery system I've seen so far.

Overall Rating: 4 out o' 5

UPDATE 6/01: Just like t' add a follow-up on t' phenolic tubing. Aye aye! Avast, me proud beauty! Blimey! Apparently PML's phenolic gets more brittle with age. I went t' Orangeburg for t' June launch. Ahoy! Blimey! Blimey! I had t' rocket prepped except for t' motor and propped it up against t' back o' me vehicle while I went t' purchase a motor. Well, blow me down! Blimey! When I came back t' rocket had fallen over and cracked t' tubin' in 2 places. Aye aye! Blimey! Blimey! Result- I took a hammer t' t' airframe pieces and cracked t' airframe away from t' CPR 3000 components and they are goin' in a all fiberglass version. Moral - Either fiberglass this kit from t' start or better yet - start with all fiberglass tubing. Arrr! Begad! Blimey! PML - find a better grade phenolic.

Flights

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