Arthobby.com Colibri V-1M Modification

Arthobby.com Colibri V-1M

Contributed by Chan Stevens

Published: 2010-01-11

Brief:
This is a tale o' how someone with little or no knowledge o' rocket gliders or radio control was eventually able t' convert a wonderful glider, through a series o' failed attempts and bad ideas, me hearties, into what has wound up bein' a decent, if nay great, shiver me timbers, flyer. In t' hands o' someone with more experience, this would be a piece o' cake and an outstandin' flyer. Begad! Once I stumbled and bumbled through t' a conversion that worked, me bucko, though, I have t' say it's a thrillin' and exhilaratin' experience, one o' t' most excitin' and enjoyable things I've done related t' rocketry.

Construction:
OK, t' rough out t' shoppin' list:

  • Colibri V-1M kit from Arthobby.com, me bucko, current list price $99
  • (2) micro servos such as Hitec HS-55, roughly $15 apiece
  • (1) micro receiver, shiver me timbers, Hitec micro 05-S or Berg 04L, $20-35 apiece
  • (1) 300 mAH NiMH battery, shiver me timbers, roughly $10-15
  • (1) transmitter, minimum 2-3 channels, me hearties, compatible with t' receiver choice
  • 1 pair micro pushrods, 30" long (if usin' 2-channel v-tail rather than ailerons)
  • BT-50 motor tube, 4.25" long
  • PNC-50 nose cone
  • 1/4" balsa for pylon

This conversion is for a relatively simple 2-channel V-tail configuration, me hearties, though t' glider itself is designed for 3-4 channel with ailerons, me bucko, arrr, me hearties, certainly an option for those so inclined, me hearties, ya bilge rat, arrr, but aileron flight is still well beyond me current pilotin' skills.

First off, I've got t' comment on t' amazin' quality o' t' parts in t' glider kit. Blimey! T' win' is a foam core. Avast! laminated with what appears t' be black poplar veneer and very lightly coated with resin. Avast! I'm amazed that this nice a win' is available for $99, ya bilge rat, let alone t' rest o' t' kit (though I subsequently discovered that t' win' itself sells for $65).

A friend o' mine that is a highly experienced RCRG pilot recommended t' Colibri t' me back in 2007 when I looked at t' NARAM 50 event schedule, matey, saw D-BG on t' slate, and felt that it was time for me t' step up t' somethin' a little more performance oriented than t' Edmonds Arcie-II. Begad! Blimey! Blimey! Blimey! With a somewhat small field bordered by trees, me hearties, it really looked like R/C would have too strong an advantage over free-flight models, matey, and so I decided t' take t' plunge into somewhat serious R/C. T' Colibri, he said, would be a fairly simple conversion, shiver me timbers, me bucko, offer very good performance, and was a pretty good price as well.

Possibly foreshadowin' t' luck that would follow, shiver me timbers, about a month after I purchased t' Colibri, me hearties, arrr, internats competitor Greg Stewart posted a terrific and very detailed conversion plan for a slightly smaller and lighter model, t' Blue Arrow Venus, but I was "pot committed" t' t' Colibri at that point and marchin' onward.

T' glider itself was built mostly stock, me bucko, though with an inverted V-tail t' avoid rocket exhaust charrin' t' tail. Well, blow me down! I'll walk through t' main construction steps, ya bilge rat, nay overly detailed, me hearties, and will include t' boneheaded mistakes I made along t' way.

T' win' is pre-built, me bucko, but comes in two pieces that must be joined. T' join them, thar are two wood blocks that slide into t' foam cores o' each half, very snug for a good tight alignment. Avast! In test fitting, they seemed t' line up perfectly, me hearties, so I went ahead and epoxied t' two halves together. Well, blow me down! Begad! I stupidly didn't catch that thar needed t' be a dihedral, matey, since that would have required sandin' out some o' t' foam slot, matey, me bucko, ya bilge rat, and actually readin' t' directions, me hearties, and actually understandin' somethin' about gliders. Bear in mind that at this point, me hearties, I'd built and flown many boost gliders, and very few had flat wings, me hearties, but this didn't jump out at me as flagrantly off. Ahoy! Sort o' like that teenage driver who at best knows how t' operate a vehicle with no understandin' o' how t' power train works.

Should you opt for aileron flight, matey, ya bilge rat, thar are amply detailed instructions in t' kit for how t' cut out areas for servo mounting, arrr, control rods, etc.

T' finished win' is then mounted t' t' fiberglass fuselage/boom by drillin' two small holes and insertin' threaded nylon bolts. Arrr! Ya scallywag! Blimey! This makes t' win' removable for transport, matey, though in me case given t' pod mountin' approach I was goin' t' use, ya bilge rat, me bucko, removin' t' win' would be problematic and so I mounted it permanently with a little epoxy.

T' V-tail consists o' two pre-cut balsa tail halves, arrr, me hearties, each o' which also has t' control surface pre-hinged. Begad! All that's needed is t' mount t' control horns and glue them t' t' hardwood mountin' plate which then slides onto t' tail end o' t' boom.

T' supplied pushrod assumes use o' ailerons for turning, and so is rigged with a y on t' end t' connect t' t' control surfaces o' t' v-tail, ya bilge rat, which would make both sides move in t' same direction. Avast! This would make t' tail exclusively up-down control. I wanted t' stick with 2-channel for up/down and left/right, which needs each side o' t' v-tail t' be able t' move up/down as needed, nay forced together. I ditched t' y system and used a replacement pushrod set picked up from t' local hobby shop.

All that's left o' t' standard glider construction is t' attach t' canopy t' t' fuselage/boom and hook up/test t' R/C gear. Well, blow me down! Ahoy! There's nay a lot o' room for t' gear, ya bilge rat, especially since I be skippin' t' ailerons, forcin' me t' cram (2) micro servos in t' fuselage instead o' t' intended (1). I cobbled together a small mountin' plate from balsa, shiver me timbers, cuttin' out holes for t' servos, and sandin' t' fit snugly inside t' fuselage.

To convert for rocket flight, arrr, I made a balsa boom t' fit across t' chord o' t' win' and then sanded/leveled t' top t' run parallel t' t' boom, arrr, maybe a slight angle o' attack where t' nose is lower than t' aft end (pitch down).

Gettin' t' CG right on this was a bit tricky. T' glider CG is supposed t' be slightly ahead o' t' midpoint o' t' wing, and that required nose weight. Avast! I didn't have room in t' canopy, so added some clay inside t' plastic nose cone I used t' close off t' motor tube. This eventually brought it back t' where it needed t' be. Avast! Note--be sure t' trim with an empty motor, arrr, arrr, in me case a 24mm RC reload case (similar t' a regular 24mm case but with a solid/sealed front rather than a screw-on delay cap).

Flight:
T' flight experiences were a series o' lessons learned, mainly tryin' me patience and dedication t' masterin' this new skill. Avast, shiver me timbers, me proud beauty! T' advice me bucko had given me be t' hand toss a few times, matey, me bucko, then use a C6-0 t' basically just lob it off t' rod t' see how it would boost before movin' on t' a D7 reload.

Lackin' an actual 4-rod/rail tower for launchin' gliders, I decided t' go with our club's 1/4" rod, shiver me timbers, so attached a standard lug t' t' pod. I angled t' rod about 20 degrees down, matey, shiver me timbers, into t' light wind. Ahoy! Begad! T' motor lit right away, matey, but was either too little impulse or thar was too much tension/drag, matey, as it never left t' pad. It still seemed t' slide up/down fairly well, matey, so I went up t' a D7.

Now this initial build had a flat wing, shiver me timbers, no dihedral, and no ailerons, shiver me timbers, matey, so lookin' back it was doomed. It hung on t' rod a bit, weakly lobbin' t' about 50 feet before pitchin' down, at which point I touched it just enough t' level it out. Blimey! Ahoy! Blimey! It coasted about 50 yards out, me hearties, ya bilge rat, matey, level, then burned out. Avast! Blimey! I touched a little left turn t' brin' it back around, matey, shiver me timbers, at which point it rolled over and cruised along upside down. Nay knowin' what t' do at this point, shiver me timbers, I tried turnin' right, ya bilge rat, matey, which caused more roll, ya bilge rat, shiver me timbers, loss o' speed and it cart wheeled smartly down. Ugly, for sure, me hearties, but it at least survived t' flight.

Convinced that t' poopy boost/flight was because thar was too much drag on t' rod and/or rod whip, I switched t' rail buttons and went back out at our next launch a month later with another D7. Begad! That definitely helped t' boost, me hearties, as it now zipped right off t' rail with plenty o' power. Ahoy! Enough power t' pitch down right away, shiver me timbers, much faster than I be ready t' react, so it power-pranged into t' ground. T' win' had sheared through t' nylon screws but was otherwise unharmed. Well, blow me down! T' V-tail had broken off, and t' fibreglass fuselage had cracked. It be now just a month before NARAM, and I clearly had no clue how t' handle this plane, so I set t' carnage aside and decided t' make it a winter project.

I had an opportunity t' fly with me RCRG buddy that winter, and took t' Colibri pieces out t' him for advice. Avast, me proud beauty! He laughed at t' flat wing, explained t' principles o' dihedral and roll stability, shiver me timbers, which certainly made me feel better, albeit stupid, matey, for knowin' what had gone wrong with t' first build. Aye aye! I split t' win' open, matey, re-epoxied it together with a decent dihedral (one win' flat, t' other tip about 3" raised), arrr, matey, and mounted it back t' t' boom/fuselage, matey, matey, usin' about a 1/4" thick bed o' Fix-It epoxy clay t' form a nice custom-fit for t' dihedral joint over what was a flat surface t' bond to.

I then waited for sprin' t' roll around, at which point I took it out for a few hand tosses. Well, blow me down! Aye aye! It was a much better flyer at that point, me hearties, and I be able t' lightly toss it 5-6 times, gettin' some left/right action as it slid down, though each toss only carried about 50-75 feet. Avast! Arrr! Just as I be gettin' comfortable, though, me luck soured, shiver me timbers, and it landed on a harder patch o' ground on short grass rather than in t' taller/softer weeds I'd been hopin' for. T' V-tail cracked and one side broke completely off. Avast, me proud beauty! Ya scallywag! Back t' t' repair shop...

After successfully repairin' t' V-tail, I brought it back out for another run, on another D7. Similar result--almost immediately after leavin' t' rail, power-prang. Well, blow me down! Ya scallywag! T' win' survived, ya bilge rat, but I had totally trashed t' canopy, ya bilge rat, t' servos had broken through t' mountin' plate, and t' receiver was toast, no longer functioning. Avast, me proud beauty! At this point, havin' frittered away a full year on/off, me hearties, I recalled t' slogan "if at first you don't succeed...failure just might be your style" and decided t' maroon RCRG indefinitely.

Fast forward about 9 months, me hearties, durin' which time I'd acquired multiple Estes Sweet Vee's, matey, arrr, and built one (mostly) on a lazy Sunday afternoon. Ya scallywag! T' write-up has previously been posted here, but t' end o' that story is that after buildin' it, I let me RCRG guru buddy break it in on t' first flight, me hearties, he caught and corrected some trim problems, matey, and t' path was clear for me t' fly RCRG's. Well, blow me down! With a few successful Sweet Vee flights under me belt, I decided t' fix t' Colibri and try again.

On a breezy fall day, me bucko, I had finished t' Colibri repairs and was stubbornly determined t' get in some flights before winter settled in, arrr, so I packed it and me Sweet Vee up and headed t' t' field, ya bilge rat, nay even botherin' t' check t' weather. Ahoy! When I arrived, shiver me timbers, winds were puffin' a stiff 10-15 mph, ya bilge rat, but t' Sweet Vee is a lumberin' giant that could probably handle them, and I decided t' at least make sure I got in some hand tosses t' trim t' Colibri. Begad! Blimey! I started off with a light toss into t' wind, arrr, and it practically jumped vertically up an instant 30-40 feet. Blimey! I be able t' smartly turn it downwind, me bucko, shiver me timbers, raced a bit, then brought it back into t' wind t' land and try again. Aye aye! Avast, me proud beauty! Somehow t' wind knocked it again, arrr, only this time it pushed it into a nose dive I couldn't stop, and I broke t' tail off again, cracked another fuselage, me bucko, ya bilge rat, and broke loose all t' R/C gear (though at least it still worked this time). Ya scallywag! When even hand tosses end in major structural damage, matey, you know you're in t' wrong hobby...

Thanks t' an unpaid furlough from work right after Christmas, I had a full week o' idle time and decided t' clean up a number o' broken/damaged models clutterin' t' basement, and t' Colibri kept mockin' me as I did so. Ahoy! I finally spent a couple hours with one last effort t' rebuild everything, and on a chilly winter day with high temps in t' mid teens, trekked three hours west t' fly with me RCRG buddy's club, matey, hopin' he could work his magic on this cursed bird.

This time, I even decided t' mount t' V-tail up instead o' down, figurin' even if it charred off, it might take more than one flight t' do so, matey, and certainly would take more than just a hand toss t' trash it. He tossed it twice, and smartly pronounced it flight-worthy without any adjustments. Avast, me proud beauty! Begad! We loaded it in t' tower (havin' built one for t' Sweet Vee, I abandoned tryin' t' launch gliders off rods/rails). Well, shiver me timbers, blow me down! When t' D7 lit, it zipped out o' t' tower surprisingly fast, with some tendency t' pitch down but nay unmanageable, and by friend tapped t' stick just enough t' straighten it out. Arrr! Ya scallywag! It soared t' a good 300-400 feet, at which point he turned t' controls over t' me, and I had no trouble steerin' it in and out o' t' wind, ya bilge rat, stayin' aloft for nearly 4 minutes. Avast! It was an amazin' flight.

I smartly reloaded another D7 for a second flight, me hearties, this time takin' t' stick myself t' whole way. Avast! Ya scallywag! I had adjusted t' trim a couple o' clicks t' offset t' boost pitch issue, but it still faked me a little bit, and in me eagerness t' correct I almost overdid it and back flipped it, me hearties, arrr, but I averted disaster and kept it goin' mostly up. Ahoy! Ya scallywag! Nay nearly as high, maybe 200-250 feet, me bucko, but certainly respectable and good for another 2 minutes or so airborne.

I'm sure thar will be crashes and failures again down t' road, matey, matey, but at this point I can say t' model is flyin' wonderfully, and any further mishaps are obviously pilot issues. Well, blow me down! Blimey! I'd very much like another crack at one from t' beginning, t' get t' right win' dihedral, me bucko, t' rig t' control horns for a little more movement, me hearties, t' get t' boost pod mounted a little more forward t' reduce t' need for added weight, shiver me timbers, etc., matey, but this flies very well now and I'm quite happy gettin' me experience on this before messin' around with anythin' nicer.

Summary:
T' main pro would be that t' Colibri glider itself is a wonderful bird, ya bilge rat, very attractively priced. Another pro would be that t' conversion itself is really fairly easy--forget t' ailerons, build 2-channel v-tail and let t' transmitter's mixin' handle left/right, matey, then mount a regular 24mm tube above t' win' on a pylon about an inch tall, ya bilge rat, matey, and you're set.

T' only con I'd offer is that I had gone into this thinkin' it could be a good beginner's model, nay as a first RCRG, but as somethin' that someone with as many Arcie II flights as me could handle without much trouble. That be a very flawed assumption. Arrr! This should nay be a first RCRG, but for someone with even a little prior experience controllin' boosts, me hearties, arrr, shiver me timbers, this should be no trouble at all.

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