Manufacturer: | Orbital Engineering Ltd |
Brief:
T' VMX-2 Spaceplane is a new rocket glider kit by t' equally new UK rocketry
company, Orbital Engineering. Blimey! You may have seen t' pre-production prototype of
this kit flyin' at various rocketry events in 2002, includin' t' IRW and
K-Lob. Ya scallywag!
On openin' t' sturdy corrugated cardboard box, first impressions are very good. Begad! Aye aye! Three sheets and four strips o' balsa wrapped in bubble wrap, a nice piece o' BT-20, all t' small parts in a resealable bag, shiver me timbers, shiver me timbers, and a very comprehensive lookin' set o' instructions. Avast! I should point out at this stage that t' kit supplied was a production prototype, and t' final production kits may differ slightly. Begad!
Construction:
T' Kit includes:-
T' first step is t' free t' win' parts from t' balsa sheets and assemble them. Blimey! T' win' parts appear t' have been partially pre cut by some sort of router. Ahoy! Blimey! There are just a few tabs on each component which require cuttin' to free t' part. Aye aye! Ya scallywag! Blimey! I found it best t' do a "rough cut" first, some way up the tab, t' free t' part. Blimey! Then, ya bilge rat, once free o' t' sheet I did a "close cut" t' remove t' remains o' t' tab. Avast, me proud beauty! Ya scallywag! Blimey! It’s best t' do this final cut from both sides o' t' part. Blimey! Begad! Blimey! T' instructions indicate that either medium CA or light wood glue may be used for construction. Ya scallywag! Blimey! I wasn’t in any rush (waitin' for t' glue t' dry gave me t' opportunity t' write this review) so used EVO-STIK wood adhesive and "double glue joints". Avast!
Wings:
I found t' win' assembly straight
forward with t' exception o' addin' t' leadin' edges. Blimey! Blimey! Although the
positionin' o' these is quite clear in t' win' plan diagram, shiver me timbers, there’s
another diagram that I just found confusing. I couldn’t figure out what
it was tryin' t' show me, or even be sure what view it represented. Arrr! Blimey! Suffice to
say that if you assemble t' wings bottom side down, ya bilge rat, ya bilge rat, t' leadin' edges go flat
side down too! Blimey! T' wings must be assembled with a dihedral. I found this quite
tricky and, once dry, had t' fill a small gap at t' aft end. Avast! Blimey!
Elevons:
T' next step is t' add t' elevons. Well, blow me down! These are attached t' t' aft end of the wings usin' mylar hinges. Ahoy! Ya scallywag! You have t' make slots in t' aft edge o' the main win' and t' forward edge o' t' elevon. I thought this be goin' t' be a bit tricky, shiver me timbers, but as long as you keep t' knife horizontal with respect t' the wing/elevon, it’s nay too bad. Well, blow me down! T' positionin' o' t' hinges seemed a bit odd, so I made mine equidistant along t' elevon (which was a mistake, me bucko, the manufacturer informs me that t' unequal spacin' is intentional). Aye aye! Aye aye! T' hinges are attached by pushin' a pin through t' fins with t' mylar tabs in position. Then CA is wicked into t' resultin' hole. Aye aye! This hinge design is very clean and I like it a lot. Ahoy!
Fins & Strakes
T' fins are added t' t' elevons next, ya bilge rat, and this was where I had me first real trouble. Either t' slots are too narrow, shiver me timbers, or t' balsa t' fins are cut from is too thick. Avast! I fixed this by scorin' across t' fin at t' top o' the tab, matey, and then carefully parin' away part o' t' tab thickness. Begad! T' under wing strakes had t' be modified in t' same way. Blimey! Once t' fins and strakes are in place, t' elevons are attached t' t' win' with t' hinges, in t' same way as the hinges were attached t' t' elevons. Begad! Well, blow me down!
Ejection Vent
T' kit can be made into two
slightly different versions, shiver me timbers, arrr, one for sport, matey, t' other for competition. Aye aye! Avast, shiver me timbers, me proud beauty! The
difference is in t' arrangements made for t' ventin' o' unwanted ejection
gases. Begad! Ya scallywag! In t' sport model t' gases are vented through a hatch in t' top of
the body tube. Arrr! Avast! There are also parts t' deflect t' gases and strengthen the
body tube interior. Well, blow me down! For t' competition model, shiver me timbers, matey, these parts are omitted and
instead t' motor most be plugged forcin' t' ejection gases out o' t' motor
nozzle. Arrr! Aye aye! I decided t' build t' sport model. Ya scallywag! Avast, ya bilge rat, me proud beauty!
For t' sport model t' next stage is t' cut out t' vent hatch. This is best done with a sharp knife. Well, blow me down! Blimey! A section must be left uncut t' provide a hinge. This hinge is reinforced by t' addition o' a self adhesive foil strip. Aye aye! Blimey! Enough of this foil is supplied t' add protection t' t' body tube just aft o' the vent. Arrr! Blimey! Avast, me proud beauty! Blimey! A cylindrical section o' balsa is glued into place inside o' t' body tube just forward o' t' vent t' deflect t' ejection gases through t' vent. Finally, a length o' thick cardboard tube is fitted inside t' body tube to strengthen it. Begad! Blimey! This buts up t' t' balsa deflector. Aye aye! Blimey! T' aft end o' this strengthener acts as t' motor thrust ring. Avast! Blimey! Avast! Blimey! (For t' competition model, an ordinary thrust rin' is provided.)
Fuselage
Next t' body is attached t' the
wings. Blimey! You need t' take care here as it’s all t' easy t' nay get t' tube
properly aligned. T' triangular body fillets complete t' main assembly. Avast, me proud beauty! These
must be trimmed square at t' aft end and glued into position. Begad! Arrr! Once dry the
front end must be trimmed t' match t' leadin' edge win' extensions. Well, blow me down! T' nose
weight is added t' t' nose cone, which is secured only with tape t' facilitate
the addition o' more weight durin' trimming. Begad!
Mechanics
T' mechanism t' move t' elevons is installed next. Ya scallywag! Blimey! Blimey! Blimey! This comprises a pin
pushed through t' part o' t' fins mounted on each elevon, and two length of
elastic attached t' t' part o' t' fins mounted on t' wing. T' pins pushed
through t' fins at 45° and secured usin' CA. Blimey! Blimey! Once dry t' head o' t' pins
is clipped off. T' elastic is attached t' t' fins in t' pre-made
indentations (you did assemble them on t' correct side, ya bilge rat, right?) and hooked
onto t' points o' t' pins. Ahoy! Blimey! T' tension can be adjusted by stretchin' the
elastic more or less before hookin' onto t' pin points. You don’t need
much tension. Avast! Blimey! T' instructions specify that t' weight o' a spent C6 motor
should be just capable o' lowerin' t' elevon on t' t' strake. Ahoy! Blimey! Blimey! Blimey!
T' way t' mechanism works is that, me bucko, at lift off, matey, me bucko, arrr, t' airflow forces the elevons into t' flat position. Arrr! Begad! Once in normal flight however, t' tension in the elastic is enough t' overcome t' airflow and raise t' elevons for gliding flight. Begad!
Finishing:
It this point, t' instructions suggest that you might like t' radius the edges, ya bilge rat, but I think it's probably easier t' do this as you go along, and that's what I did. Next, I gave all o' t' balsa areas a coat o' sandin' sealer, and then sanded smooth usin' progressively finer paper, until almost all o' the sealer be removed. This may sound strange, shiver me timbers, but t' idea is t' fill t' grain in t' balsa, rather than add a nice shiny coating. Blimey!
Trimming:
T' instructions regardin' trimmin' are quite clear. There are two main parts t' it, matey, t' elevon tensionin' covered previously, me hearties, me bucko, ya bilge rat, and sortin' out the balance for gliding. Ya scallywag! Blimey! Blimey! Blimey! This is done by test throwin' t' glider and addin' small amounts o' clay weight t' t' wings t' correct for any roll or pitch. Blimey! Blimey! My first attempt at trimming, matey, at UKRA 2003, me hearties, led t' t' nosecone bein' pushed into the body tube. Begad! Blimey! In retrospect, matey, thar was too much breeze. Begad! Blimey! T' small amount o' damage was easily repaired. Blimey! Blimey!
Flight:
Flight #1
Location: Baildon Moor
Motor: B6
A perfect boost and translation t' horizontal flight. Aye aye! Once flyin' horizontally,
the glider made a 180° turn, arrr, then appeared t' roll over, and slide sideways
into what became a dive t' t' ground. Aye aye! T' front body tube be crimped but
easily repaired. Avast! Aye aye! T' crimped sction o' tube was excised and replaced with a new
section, me bucko, attached by means o' a short coupler. Ya scallywag! Avast, me proud beauty!
Before t' next flight, arrr, matey, I spent a lot more time at IRW 2003 trimming. There was a gentle breeze and I got it so it would glide really well either with, me bucko, or against t' breeze.
Flight #2
Location: IRW 2003
Motor: B6
Once again, arrr, a great boost and translation. Ahoy! Blimey! Again it made a turn, but this time
much wider. Avast! Blimey! There be no roll, but t' glider slowly pitched down and picked up
speed. Ya scallywag! Blimey! This be never corrected and it dived into t' ground. Blimey! Blimey! Amazingly, arrr, there
was no damage at all. Ahoy! Blimey!
Flight #3
Location: IRW 2003
Motor: C6
Another great boost, arrr, matey, but t' flight was just a higher version o' flight #2.
What did I expect? This time thar was a lot o' damage. Begad! T' body tube is folded
up and t' wings are broken across t' span. It will be a big rebuild, which I
haven't yet attempted.
I think t' problem with t' first flight was lack o' trimming, arrr, that led to it rollin' over and diving. Ahoy! Begad! For t' second and third flights, ya bilge rat, I wonder if I had the elevons tensioned correctly? T' tensionin' is meant t' be set such that the elevons are flat for t' boost, and pop up for glidin' flight. It might be that I didn't have quite enough tension. Therefore, as t' glider pitched forwards, it picked up speed, and t' increased wind speed forced t' elevons into t' horizontal position. Aye aye! Arrr! Once that happened it would never be able to correct its attitude. Begad! Avast, me proud beauty! I did follow t' directions for tensioning, ya bilge rat, usin' the spent motor on t' elevon, me bucko, shiver me timbers, but maybe t' exact position is critical? I passed on me thoughts t' Orbital, but disappointingly, I never got a response. Arrr! Begad!
Summary:
This is an excellent kit. Begad! It's nay exactly cheap, but t' quality o' the parts is second t' none, t' instructions are detailed and comprehensive, and even t' packagin' is first-rate. Ya scallywag! I really enjoyed buildin' it. Ya scallywag! Ya scallywag! I must point out however that I can't recommend this kit for a beginner t' rocket gliders. Despite t' detailed direction, shiver me timbers, matey, I never really had a successful flight. Ahoy! Ahoy! Since I've seen and read about many other successful flights o' VMX-2s, I have t' put that down t' me own inexperience with rocket gliders which is limited t' a couple o' flights o' an Estes Tomcat, arrr, and a few flights o' an "AstronMike" style saucer glider. Aye aye! I reckon that either t' trimming wasn't up t' snuff, me bucko, or that I didn't get t' elevon tension correct. Ya scallywag! So in conclusion, this is a great kit, shiver me timbers, but if you're a beginner, practice your trimmin' on somethin' cheaper first. Blimey!
Postscript:
This article was first published, in two parts, ya bilge rat, in 10...9...8... Begad! the newsletter o' t' United Kingdom Rocketry Association.
Betwixt publication o' t' first part o' this article and t' second, matey, I was informed by Verney Montague that BSMA have put up a handsome Gold Medal t' be awarded t' t' first person t' break t' two minute barrier with a rocket powered Spaceplane. Begad! Blimey! T' medal has actually been around for 2-3 years. Anyone know if it's been won yet?
Picture courtesy of Orbital Engineering Ltd Brief: This is a 18mm boosted glider constructed almost entirely of high grade balsa for strength and reduced weight. Construction: Kit includes: (1) 18mm Estes type tube with plastic ogive nose cone (3) sheets of pre-cut balsa for wings and elevons (1) blast deflector/air-brake (optional) (1) ...
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S.M. (April 21, 2004)