Glens Models Extra 330S

Kit purchased October 2005 1st flown December 2005

pensioned off September 2007

Why this model?

Glen Fletcher has been producing model aircraft kits since 1989 and they all have a deservedly high reputation.  I bought my previous Glen’s model, the 58” CAP 232 straight off the stand at Sandown in May 1999 (having gone there strictly with the intention to observe only) as I instantly fell in love with the beauty of the uncovered airframe. All his models are produced with the majority of components CNC cut from lite-ply, and the accuracy of the parts are second to none that I know of.

Before I settled on the 68” Extra 330S as my next project, I had a long hard look around the market, and as usual moved from one definite final decision to the next definite final decision, depending on the wind direction! The main criteria was that the chosen model would suit the Laser 150 I had earmarked for the job, would be capable of full on aerobatics, bordering on 3D, would look good and be enjoyable to build. I finally settled on the Extra 330S after a brief email or two with Glen, who is a very helpful guy, and duly purchased the kit complete with the decal set.

Kit and Contents

As expected the first impression on opening the kit is of the neatness and accuracy of the CNC ceba lite ply parts. The fuselage and wing are constructed almost exclusively from this material, with balsa being reserved for the tail feathers and sheeting. Construction consists of freeing the parts from the main sheet and then clipping them together. A simple instruction sheet, with a few pictures, comes with the kit or can be downloaded from Glen’s web site. The image resolution was a bit better from the web site than the photocopy in the kit, and was worth downloading.

The kit comes as standard with high quality epoxy glass cowl and spats, a very strong epoxy glass undercarriage and a large vac-form clear canopy. There is also a good selection of linkage parts, surface control horns etc, as well as main wheels and tail wheel with bracket. There is no tank in this kit due to vast engine range it can accommodate. I chose to purchase the decal kit as it was easier than thinking up an alternative colour scheme. It’s a good scheme as well!

Fuselage Construction

There is a bit of a decision to make before you start, depending on the power plant you are using. The model is capable of being powered by a vast range of engines, from a .90 2-stroke, through a 1.20 4-stroke up to a Zenoah 26 petrol, if you want truly unlimited vertical performance! The only difference is that the engine bulkhead needs to be moved back for the heavier engines.

The Laser 150 is mid-range I guess, but I wanted to fit three servos at the rear (2 elevator, 1 rudder) instead of two and a closed loop on the rudder as I prefer the simplicity of the direct drive off the servo. I did some back of the envelope calculations and concluded that if I left the engine mount a full length, and mounted the receiver batteries as far forward as possible, I should achieve the balance point. So that I was what I opted to do.

The final engine and battery mounting arrangement can be seen in the photographs. After that I was just a question of proceeding with the built according to plan.

As I have said the lite-ply parts fit together ‘perfectly’ and construction consists of clipping various parts e.g. tank bay, fuselage sides, top, bottom and formers, and when everything is in place running thin cyano into all the joints. The various parts are cleverly designed so that you cannot fit a similar looking but different part in the wrong place (unless you are totally ham fisted!). The model can be built without a jig as both fuselage and wing parts fit together in such a way that accuracy of alignment is assured.

The fuselage is quite straightforward. The only thing worthy of additional mention is Glen’s method of reinforcing the engine bulkhead with small squares of lightweight glass cloth and more thin cyano. This was novel to me (I think I ignored it when I built the CAP232 six years ago!).

I also added the same reinforcing to the undercarriage plate, although this is probably belt and braces as it is solidly constructed anyway. I have yet to test the theory of a clean break, and long may it remain untested.

I did find that I had to use an additional plate to mount the engine, again clearly visible in the photographs. The nylon engine mount I used with the Laser 150 was just slightly wider than the bulkhead. It was also asymmetrical so that it over hung the bulkhead beneath the engine. I think this is peculiar to the Laser and my mount, as Glen assures me that even a Zenoah 26 will fit directly onto the model.

Wings and Tail Feathers

The wing construction is also very straight forward, with the lite-ply ribs fitted over the cyparis spars. Glen has clearly gone to a lot of trouble to select the types of wood for this kit, and the quality of the final material supplied is superb. As stated, the accuracy of fit ensures that wing can be built without a jig. There is one stage in the wing construction that threw me for a while. Having assembled and glued the ribs and inter-spar webs to the main spars, and nothing else, it is stood up on the trailing edges of the ribs and then glued to the trailing edge strip. This was counter intuitive to me, to my mind you don’t up end a partially built wing and expect it to remain true. Well, in this case you do, and it does! However, this is one part of the instruction where a different set of words and an additional picture would have been helpful.

The tail and fin etc are straight forward balsa construction. I did deviate from the kit with the tailplane. The tailplane supplied is a solid sheet construction in 9mm balsa. This was quite heavy to my mind. In view of my intention to fit a third servo at the rear I cut the sheet supplied into strips and constructed the tailplane as an open balsa strip framework. Out of curiosity, I weight the component parts supplied and the final open framework and found that I had saved 40grams, which coincidentally is virtually the weight of a servo.

Installing the electrickery bits

Radio installation is simple. There is enough room in the fuselage to hold a small dinner & dance so a receiver and stuff is easily lost. As I have said I fitted three servos to the rear and two in the wing, all standard Futaba 3001’s initially. I have since replaced the rudder servo with a digital version, just because I had one really. I decided to use Pete Tindal lightweight ali horns and carbon fibre pushrod assemblies, as they ensure a slop free connection between the servo and the control surface.

As you will see in the photograph, I ended up with the receiver batteries right up front with the engine. You may also notice of you are eagle eyed the throttle servo mounted in the engine bay. This was a late addition when I thought the balance would be wrong. I attempted to glue the servo mount to the fuel proofed ply side plate. It only lasted a few flights before the glue gave up, so I refitted the servo back inside the fuselage, and every thing was fine. (I was wrong once; it was when I thought I was wrong but it turned out that I was right..tee hee) I also fitted an onboard glow system to the Laser. This was for convenience during starting, particularly as the Laser is completely enclosed within this cowl.

Covering and finishing

I finished the model in Profilm as recommended. I have used this in preference to other iron on coverings for many years, as I find that the ease of use, the strength and in particular the tolerance of heat settings is well worth the extra cost. The cowl, spats and undercarriage were spayed with acrylic car paint from my local car factor shop. The gold pin striping was standard self-adhesive Trim-line. However, I found that I needed so much of the thin strips that I ended up cutting my own from the thicker ones. I’d have used up the world stock of gold Trim-line if not. Once the decals were applied I sealed them, the edges of the Trim-line and the cowl, spats and undercarriage with brushed on gloss Tuffkote. Pilot is from Pete’s Pilots painted with acrylic – don’t use enamel, I did to start, it didn’t dry.

The colour scheme is based on the one adopted by Patty Wagstaff, and although the sponsor has changed, and details can be seen on her website at http://www.pattywagstaff.com/index.htm. I chickened out of attempting to paint the white checks on the front of the cowl; it has too many curves. Glen now sells ARTFs of this kit, and they come with the checks on the cowl, so if you are keen you may be able to buy one ready painted.

The whole build process is very straightforward and relatively quick, but I think I spent more time covering and finishing than actually sticking wood together. The only thing I would add is that you do use a fair amount of cyano and sometimes a lot in one go. I know we all use it these days but be aware that the fumes can be irritating in large volumes, so ensure that the workshop is well ventilated.

The Big Day

Having completed the model in late November (it was an early Christmas present – very early) I had to wait a few days for a suitable weather window. The day eventually arrived with a moderate breeze blowing straight down the strip, and some nice wintry sunshine.

I spent a few minutes checking things over again, and doing a full range checks. In particular, I wanted to ensure that having three servo leads running parallel to the receiver aerial would not give problems. It all checked OK so I refuelled and taxied out onto the strip. Opening up the Laser whisked the model into the air in a very short space indeed and she climbed out perfectly into the sky. A couple of clicks of left aileron and she was flying beautifully. Almost immediately I felt relaxed and in charge. The Extra flies positively and with authority, and immediately gives you confidence that it will do what you ask and nothing more. The aerobatics where smooth, and as wide, or tight, as I wished to make them.

The Laser 150 gives ample vertical performance, as to be expected with a model that tips the scales at 10lb dry weight. Landing was a dream; she floats in like a trainer, except with more positive responses. I can honestly say that in 30+ years of flying model aircraft this is the best one I have owned by a long stretch.

Since that first flight I have trimmed her out, which amounted to just fitting 25g of lead to the left wing tip (probably to counter balance the side-mounted engine). Nothing else needed tweaking at all. All I have to do now is improve my flying skills so that I can get the most out of a superb model.

To sum up, the kit and the resulting model are virtually faultless. To paraphrase a well know advertisement “If Carlsberg made model aircraft they would probably make this one”. It is much admired by my fellow club mates both, for its looks and its flying. It has a certain presence in the air and makes the struggle with the winter mud outside our flying field worth the effort.

Well done Mr Glen Fletcher; an excellent model.

LATEST: 17th April 2006. Smashed to pieces; wing survives virtually unscathed but fuselage is a bag of bits! The engine died without warning and turning back towards the strip into a very stiff breeze resulted in a (I think) a tip stall and spin in form about 100ft. Took me completely by surprise it's never shown any tendancy to tip stall before. Might have been wind shear, another model fell out of the sky on lnading approach earlier, but I tend to dismiss these reports as 'pilot error excuses'; except when they happen to me of course.

A new fuselage kit was duly purchased along with a Zenoah 26; which is the first time I have run a petrol engine. Initial indications was that this was brilliant combination even though the engine was still loosening and not on full power. However there was a problem with a loss of power when knife-edging. A word with Glen Fletcher suggested a cure, which I fitted. The following evening I went out again and found the problem was cured when on one edge, but not the other. While 'exploring' this the engine cut completly and once again I was too low to recover and the fuselage was smashed yet again after only two days flying

This discouraged me more than a bit (I was totally pi**ed off to be honest) and so I put it aside while I went on holiday. While on holiday I devised a scheme to re-built the fuselage from the remains of the two crashes, which I have now done. The Zenoah wouldn't run however, but I have returned it to Glen who has found the problem. Just waiting for everything to come back together for another go! 03.08.06.

Last chapter (Jan 2008)

The Zenoah was sorted and installed in the rebuilt fuselage. However for various reasons I was never totally happy with the model again. It suffered a number of small prangs, mainly due to my incompetence during landing. It does require to be 'flown in' properly other wise it will tip stall if slowed down too much. So after a lack lustre winter and summer 2007 I took the gear out of the airframe and pensioned it off. The engine and radio was put into a Funtana 100X which (so far) seems to suit my flying style much better.

Back to top