Titan 120 (oz12171)

About this Plan

Titan 120. Radio control sailplane model. Wingspan 120 in, wing area 886 sq in.

Quote: "The Titan 120 is an all balsa super-light slope soaring glider, for two-channel radio control. The ship quickly disassembles into a compact unit for transportation and storage."

Note this plan is derived from raw scan posted 25/02/2020 on the AF site (see datafile), by 4MrKite. Cleanup here by Pilgrim.

Update 15/08/2020: Update 15/08/2020: Added kit review from RCM&E, January 1976, thanks to RFJ.

Quote: "Kit review: Terry Plane Titan, by Ray Favre.

THE 'Titan 120' comes from Terry Plane Inc in USA and is one of the interesting range of kits imported and marketed here in UK by Eynhallow Avionics. The model is a 10-foot span thermal soarer which can be used as a slope soarer by simply unplugging the wing tip panels to reduce the span to 6 foot.

All parts, except wing sheeting, are supplied ready cut, including wing ribs. The quality of all wood was good, although a few of the light strips for constructing the tail-plane and fin/rudder later proved to be too soft.

Perhaps the most impressive point when opening the kit is the special additional instructions/hints included by the UK importer as a result of their stated policy of building and trying each model before marketing it in UK. This puts you in a good mood for a start and it wouldn't really matter after that if these additional instructions weren't very important. As it happens, there are indeed half a dozen useful points which could only have been discovered by building and flying the model. So, one up to Eynhallow Avionics - a good practical selling point. Other importers may do the same, but they don't say so.

Building: It is important to keep to the correct sequence of building in one area - the tailplane needs to be built before the fuselage (in order to use the all-flying tailplane pivot as a jig). The plan comes in two rolled sheets with instructions printed on them and my only gripe about these is that the sheets start to turn brown rapidly and the paper is very brittle - so it looks as if the plans are photo-copies rather than dye line prints.

Wings: These are straightforward but not entirely conventional in building sequence. The whole of one wing half (including tip panel) is built virtually as one piece and separated after-wards. The other slightly unusual procedure is that the complete underside of the wing (leading edge sheeting, cap strips and TE lower half) is glued together, pinned down and allowed to dry before the ribs and spars are added.

The two inner wing panels are joined permanently with a hefty ply dihedral brace plus glass-fibre tape reinforcement. Wing section is flat-bottomed and tip washout is built in over the last 18 in of each tip panel.

The kit box carries a separate sticker claiming 'New High Performance Airfoil' but I'm going to risk being called an idiot by saying that it looks like most flat-bottomed sections to me. Perhaps the 'new' refers to a change in the kit recently.

The review kit wings ended up with three differences compared with the plan: the most important of these was clearly intended in view of the materials supplied, but the plan showed it differently. This modification con-cerned the piano wire dowel which joins the wing tip panel to the main part of the wing. The plan shows the wire dowel fixed solidly to one half of the wing and locating in a brass tube in the other part. I had already made up my mind to use tubes in both halves (keeping the dowel completely removable) when to my surprise the tubing supplied was clearly in-tended to do this anyway - whatever the plan showed!

The second modification was to add very short locating tubes and thin wire dowel near the trailing edge to act as positive alignment devices. The instructions say use adhesive tape at LE and TE after assembling to fly - but I feel that the addition of a short locating dowel is far superior. Otherwise with only one dowel, I had visions of rotating wing tips!

The third modification was simply to add thin plywood pieces on top of the wing TE at the roots to reduce the chances of damage from the wing fixing rubber bands.

Finally, if you intend to use the model on the slope often, you might consider making a pair of shaped tip blocks to plug into the ends of the main wing halves when you remove the outer wing tip panels. It will make the shortened version look less stark.

The tailplane and rudder: The all-flying tailplane is built in one piece around a wooden dowel which later becomes the tail pivot on the fuselage. When the tail-plane is dry, the dowel is removed and the tailplane is then cut in half and finished. The rudder, or more nearly an all-flying fin, is built up conventionally and is then hinged to the rear end of the fuselage. The latter has a short stub fin built into it to com-plete the fin/rudder shaping and to hold the all-flying tailplane mechanism.

The tailplane uses diagonal 'ribs' which leaves fairly long runs of leading-edge without support. It was here that the very soft LE strip proved inadequate because it yielded under a single coat of dope on tissue - leaving a 'scalloped' LE stiffer strip or a couple of light extra braces would prevent this and I chose the latter method.

The fuselage: The structure is simply a 'slabsider' with triangular section longerons at each corner. Cross-grained top and bottom sheeting in-creases the basic strength considerably - at the cost of building time.

I have to admit to not being very happy when I started building the fuselage. It looked far too flimsy for 'yer average UK usage'. No ply doublers; fairly long nose moment with no formers. However, the importers do supply glass fibre tape in the kit and recommend that it is used inside the fuselage from behind the wing position right through to the nose. It certainly makes a difference and only time will tell whether my forebodings are correct.

Two other points about the fuselage. A fairly self-evident weak spot looked like being just in front of the fin/tail support. The fuse-lage sides are required to be bent concavely there (unusual). Again - only time will tell. Secondly the rear wing support dowel needs at least some thin ply doublers to prevent the dowels simply pulling the top off the fuselage. Inside the fuselage would be best, but I did not notice this point until late and had to add mine to the outside.

One thing the fuselage does have is plenty of space, which is a pleasant change in gliders. The fuselage is completed with a built-up balsa canopy.

Despite having a very angular look about it when building, the finished fuselage is strangely attractive and functional. For those who like to ballast up models I should men-tion that both the mid-fuselage and the wing centre-section covering have ample space into which to build ballast boxes.

Controls and finishing: Hardwood dowels and end-threaded wire are provided for normal push rod operation and I found this method very satisfactory.

As stated earlier, the fuselage is large enough for any gear and will even take a 500 mAH DEAC sideways up against the noseblock (with foam padding round it!). So the receiver and servos are no trouble to fit.

Rudder hinge material is supplied and it is of a type I haven't seen before. It is reminiscent of a bicycle tyre puncture patch before peeling the backing off. It is very flexible and looks very tough. (Thinks - a bicycle tyre puncture patch for my next model! Can I suggest it for Handy Tips ?) I used a normal office stapler to prevent pull-out of the hinges after epoxying them in.

I finished the model with coloured heavy weight tissue with my usual wing zebra-crossing pattern. I always find this pattern gives very good visibility at distance and at least they all recognise my models by now!

The completed weight was 43 oz. which gave a wing loading of just over 7 oz /sq ft (with the tips removed the loading went up to just under 9-1/2 oz /sq ft - quite a large percentage increase, but still a lightweight).

The CG came out to be 1/4 in in front of that shown on the plan, without any additional ballast and as I expected the first flights to be on a slope rather than 'flat-field' I didn't bother to adjust the CG position at all.

Flying: Your Editor and I chose a perfect day for the first flights - warm, breezy, but not too powerful. Titan 120 flew straight off and up with absolutely no problems and the first flight was about 15 minutes. Sensitivity to movements of the all-flying tailplane is quite high and with my Futaba linear servos available movement is rather too much. Once completed it is not possible to alter the moment arm at the tail end and thus a rotary servo would be advantageous for this control function. Rudder sensitivity is adequate, but I would recommend as much movement as possible for 'flat-field' work. The minimum moment arm possible using the provided rudder horn is 7/16 in. When combined with 9/16 in movement from the Futaba linear servos the resulting rudder control was sufficient, but I will be trying to squeeze a little more for future use just in case.

Manoeuvrability near the ground is good for a large soarer and indeed I felt so confident that I deliberately made several short flights at the end of the session to try out landings with it - not my usual practice at Ivinghoe with a 10 foot span model!

As the conditions were not marginal, we were able to test the model in the short wing mode on the same day. Apart from a faster flying speed and more sensitive rudder control the short-spanned model was just as easy to fly. It looks very stark in this mode though, rather like a WW2 flying bomb to look at. But the important point is that it does fly well in this shortened version and would make a good basic slope trainer. Pitch sensitivity is still quite high though. This pitch sensitivity caused a few laughs in fact. A chance remark to your Editor led him immediately to have a stir of the stick himself and to try to loop it on the trim lever alone! He didn't quite make it, but I think he would have done if he'd been allowed to continue!

Summary: A pleasing and easy model to fly and fairly simple to build. Make the rudder throw as much as you can, but keep the all-flying tail movement small. My misgivings about the fuselage stength have so far proved groundless but don't forget to use the fibreglass tape and resin inside the front end."

Supplementary file notes

Review.

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