She’s a great first low-winger is the Venus 40
Welcome back once more. We have reached the last instalment of the Great Planes’ ‘Venus 40’ assembly and flying saga. While the previous two parts dealt exclusively with airframe assembly matters; this time we finally get to the exciting bit – flying! But first, the few remaining airframe-completion tasks lie ahead. The most important of these jobs is the fuselage radio installation, so let’s start with that.
TALK RADIOArticle continues below…
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Glue the ply servo tray into the radio bay with medium cyano, aliphatic resin or fifteen-minute epoxy. Allow the adhesive to dry and then install the servos.
Pop the throttle, elevator and rudder servos into the pre-cut tray recesses. The openings suit standard servos so alterations are, generally speaking, unnecessary. If you have to tweak the openings, trim material away with a sharp number scalpel or add scrap lite-ply mounting strips, cyanoed on, depending on whether the openings need enlarging or reducing.
Align each servo accurately by hand and drill through the (already-fitted) grommets in-situ, then screw the servos down, being careful not to over-tighten the small self-tappers. Temporarily remove the servos again. Squirt thin cyano into the just-drilled holes to toughen the wood. Allow to dry, then re-fasten the servos.Article continues below…
The throttle, elevator and rudder linkages are 16SWG wire pushrods running in plastic outer tubes. Each pushrod uses a plastic clevis at the threaded carb/control surface end and a plastic swing keeper at the unthreaded L-bent servo arm connection. On my model, the elevator and rudder pushrod positions were reversed in relation to the layout shown in the assembly manual. This presented no problems, other than to be aware of the fact when hooking up the servos. We installed the throttle linkage outer tube last issue and the elevator/rudder outer tubes arrive factory-fitted on the Venus.
Switch on the radio system and neutralise the elevator and rudder servos. Configure the servo movements via the Tx menu or servo travel reversing switches to suit the required linkage hook-ups. Fit straight servo arms if at all possible, as they’re much less likely to clash on the swing keepers at extreme angular deflections.
RADIO PLAYArticle continues below…
First of all, we’ll connect the throttle linkage; remove the cowl during this step. Screw the clevis on to the throttle pushrod the recommended amount of turns. If the clevis is hard to twist, grip it with a small piece of 400-grade glass-paper and it will turn easily. Ensure that you have ‘symmetrical’ clevis adjustment leeway.
All snug and sound, a good R/C installation can’t be rushed!
Feed the pushrod through the already-installed tank bay outer tube from the firewall end and see how the clevis engages on the carb’ arm; I had to bend my wire quite a bit to get it to line up. Clip the clevis onto the lowermost carb’ arm hole and check for free movement by manually pushing/pulling from the radio bay.Article continues below…
Move the tranny stick and trim lever to the full throttle setting and open the carb’ air intake fully via the connected pushrod. Ensure that the servo arm is rotated forward 45-degrees at this point so that it won’t ‘overdrive’ the carb’ barrel on the ‘throttle shut’ phase.
Maintain this linkage position and mark the wire just ahead of the outermost servo arm hole with a black fine-point felt-tip pen. Temporarily disconnect the clevis from the carb’ arm. Move the pushrod backwards so that you can work on it. Gently raise the servo end of the pushrod out of the radio bay and bend the wire upwards at 90-degrees where marked using small square-tipped pliers. The bend doesn’t have to be precisely at right-angles to the carb’ arm because it will be possible to adjust it straight again by tweaking the clevis. Snip the wire off 3/8” beyond the bend with wire-cutters.
Reconnect the clevis to the carb’ arm. Remove the servo arm and feed the bent/snipped wire up through the outermost hole, engaging the swing keeper at the same time, then re-fit the servo arm to the full throttle setting. Adjust the clevis at the carb’ arm to get an unstressed, ‘squared-up’ linkage. You should get pretty well-sorted carb’ movement first time, but too much or too little movement is easily compensated for by moving the linkage to a different carb’ arm or servo arm hole, or by altering the servo end-point in your transmitter menu.
The Irvine .53 has been a great motor for the Venus
The carb’ opening/Tx throttle stick positions to aim for are: stick and trim lever fully forward – carb’ fully open; stick and trim lever fully back – carb’ fully shut; stick fully back, trim lever fully forward – a reliable slow-speed idle.
My carb’ clevis fouled on the cowl interior at the full throttle forward position. It was a simple matter to cut a small hole out of the cowl in the manner described last month to prevent linkage strain.
Bolt on the elevator and rudder horns, making sure that the horn arm-holes sit at right-angles to the hinge-lines with the control surfaces neutralised.
The independent elevators use two pushrods running in adjacent outer tubes. When bent to suit, the pushrods come together to be united by a pair of grub-screw-tightened collets close to the servo arm connection.
Screw the clevises on to both pushrods the recommended distance and insert each from the tail-end. Initially only connect the pushrod that meets the servo arm in the straightest line to the outermost hole on its matching elevator horn, and temporally slide and clamp the two collets a few inches in along the wire at the servo end. Leave its partner pushrod disconnected for the time being.
Neutralise the connected elevator manually and mark the pushrod wire where it meets the outermost servo arm hole. Be absolutely certain that the elevator servo is centred when doing this. Temporarily disconnect the marked pushrod from the horn. In the radio bay, bend the wire upwards in-situ at 90-degrees with small square-tipped pliers and snip excess away as for the throttle linkage. Connect the pushrod with the swing keeper through the outermost servo arm hole and adjust the clevis for an absolutely neutralised elevator half. Check for full-and-free movement.
Connect the remaining pushrod to its horn and neutralise the other, still floppy elevator half to match its fixed partner. Bend the wire at the servo end as shown in the manual to mate with the first pushrod and snip away the excess. Loosen the waiting collets from the first ‘sorted’ pushrod and feed the second pushrod in through them near the servo, so that both wires can soon move as one unit. Keep the collet grip a friction-fit until the second elevator half is precisely aligned relative to the first, and then tighten both collets thoroughly. The instructions suggest applying thread lock to the collet grub-screws, but I didn’t bother. Check again for full-and-free elevator movement.
Handle the rudder hook-up using the method just described for the throttle and elevators.
The servos and control linkages are now fully operational. Finally, slip the recommended (and supplied) short silicone tube sleeves over all clevises to prevent accidental disengagement.
Now install the NiCad, receiver and the receiver on/off switch ahead of the mounted and connected servos. Place the NiCad close to the tank with the receiver behind to minimise the need for nose ballast. Tidy the servo-to-receiver cable connections with small tie-wraps and use rigid foam rubber to protect the delicate electronic components from potentially damaging engine vibration. I held the foam-protected gizmos steady with scrap hardwood cross-pieces cyanoed to the inner fuselage sides. To avoid unwelcome ‘gunge contamination’, mount the on/off switch on the fuselage side opposite the exhaust or use an extension wire actuator through the fuselage side.
Thread the receiver aerial through a shirt button strain relief ‘stop’ inside the radio bay and feed the aerial portion behind the button out through a small builder-drilled hole in the fuselage underside aft of the radio bay. Tension the aerial to the tailwheel bracket via a small rubber band and short length of fuel tube.
The dural undercarriage is fastened to the fuselage nose underside with a pair of socket-head bolts going into factory-installed anchor nuts. Two more socket-head bolts and four hex-nuts hold the GRP spats and wheels in place. Holding the internal hex-nut steady as its external partner was tightened to keep the spat firm while juggling the internal washer, spacing collet and wheel was a bitch job!
Even firmly gripped with needle-nose pliers, the internal hex-nut tended to slip. If you can find one, a small flat spanner is ideal for gripping the internal hex-nut. Eventually, I achieved a reasonable but certainly not outstanding result.
As it turned out, the spat fitting exercise was futile. They look gorgeous but, alas, they quickly came to grief and broke off in my rough pasture flying site!
I didn’t fancy the glossy light grey Monokote as a cockpit base colour, so I brush-painted the area with matt black Humbrol before adding the self-adhesive instrument panel decal and a suitably prepared civilian pilot figure by Williams Brothers. Don’t leave the cockpit bare – it looks awful! But, avoid sticking dolls or cartoon characters in the ‘office’ too. Can there be any more misguided act of ‘aeromodelling psychosis’ than to ensconce a leering Ninja Turtle or some other such monstrosity in the cockpit of an R/C plane?
As you can see the fus’ has been formed to accomodate a silencer if a 45-degree angle is preferred
After washing/drying it and sanding its inner rim, I stuck the clear canopy in place with a combination of Evo-Stik impact adhesive along the sides and half-hour epoxy at the front and rear edges. The instant impact adhesive bond held the canopy nicely while the slow-set epoxy went off.
The fin and horizontal stab junctions were disguised by 1/2” strips of white Solartrim, cut to size with a sharp scalpel. Every strip was applied over-long, centred on each junction, pressed into place at one end, and then hand-tensioned as it was pressed into the joint-lines with a piece of hard 1/8”-square balsa strip.
The sticky-back ‘Venus 40’ name decals were easy to position after being cut out with scissors. Cut closely to avoid a ‘stuck on’ look and slide ’em into place using the warm soapy water positioning method. (Mix a few drops of washing-up liquid in a small basin of warm water to act as a ‘sliding solution’.) When each design is located accurately, squeegee excess soapy water away with an old phone card and pat dry with kitchen towel.
I strongly recommend that you finger-smear some fifteen-minute epoxy over the factory-applied trim pattern edges and along the wing- and tail-tip covering seams. This is because my model’s ‘skin durability’ proved to be sadly lacking. After only a few flights the covering lifted badly and no amount of re-sealing would give a really permanent hold-down. I wasn’t impressed!
FLYING TO VENUS
Balance the model inverted with an empty tank using your fingertips or a specialist balancer device. Ensure that it hangs level or slightly nose-down when lifted at the specified position and add nose ballast in the form of cut up sheet lead screwed to the firewall, if needed. Whatever you do, don’t fly it in a tail-heavy state! That ‘trim configuration’ is bad enough on a stable trainer, but with a hot ship such as this it’s an especially effective way of re-kitting the model in record time!
Also balance the model laterally (span-wise) if required, as it’ll prevent one-wing-low looping manoeuvres. Get a friend to hold the prop shaft while you lift the model beneath the fuselage under the fin trailing edge. If the wings remain level, all is as it should be. If one wing drops, drive some nails into the light tip leading edge until the model stays level when suspended. When the balance is correct, cover the nail heads with a patch of heat-sealed scrap Monokote or Solarfilm.
Check that the control throws and deflections are correct one last time before going to the field.The good news is that it’s easy to solo hand launch the Venus 40. Just hold it around the canopy in a slightly nose-up attitude, rev up, push it outward and upward, and off it goes. In my case, with the Irvine 53 on full chat, it accelerated in a spirited fashion almost vertically after release, so rapid throttling back and levelling out was called for.
Generally speaking, it’s a very lively and agile aerobatic machine. It’s been ages since I’ve flown a ‘pattern ship’, and this creation quickly reminded me of just what I’ve been missing!
I’m a nervous flier, but I still enjoyed engaging in various deviations in both the looping and rolling axes. I was struck by how responsive it was to small control surface inputs, and all controls were very positive indeed. With the pitch/roll/yaw controls neutralised, recovery from manoeuvres was practically instantaneous. The model displayed ‘neutral stability’ insofar as it would go where directed until such time as a course change was dialled in.
This is an ideal design on which prospective aerobatic fliers can hone their skills. I’m not a competitive flier, so I just relished the thrill of badly executed and positioned inside and outside loops, ‘ordinary’ and snap rolls, stall turns, reversals, Immelmans, upright and inverted spins, inverted ‘fright’, low passes and overshoots.
During this carry-on, I particularly liked the super-quiet tone of the Irvine engine – the aircraft sounded more like an electric model than a glow-engine-powered device! In the throttled back phases, one would think that the engine had cut. But it hadn’t – it purred back into life once more when the throttle was ‘gunned’. This was especially satisfying during spin recovery – instant reliable power from apparent ‘nothingness’!
After all this, I was surprised to find that the model could bite if the ‘slowed-down’ handling and landing wasn’t treated with due care and attention! There was a pronounced tendency to tip-stall if it was held in a slow speed nose-up attitude for too long. It seemed better to a keep it level longitudinally until it touched down. In other words, don’t stretch the slow speed bits, the final leg of the approach or the dead-stick glide by pulling back excessively on the elevator stick.
The Venus will suit all abilities and deliver a satisfying aerobatic performance
Strangely, the tip-stalling tendency lessened when the wheel spats were removed. Any theories about that symptom?
Ground take-offs are simple. However, it is a good idea to do some taxi tests before lifting off to get the feel of the rudder steering.
Point the model into the wind, hold the rudder-tip and check the throttle response. Release the model, rev to full throttle and steer it with dabs of rudder as required. Initially hold on a little up elevator to stop it nosing over but neutralise it gradually as the speed builds. Let the forward momentum take hold and then apply more back-stick, whereupon it should lift off smoothly. Keep the wings level with ailerons and rudder and maintain a shallow climb-out into wind until it becomes established in its element.
I hope that this article series has inspired you to assemble and fly your first-ever low-wing ARTF sport/aerobatic model. When you’ve become accustomed to R/C flying by way of a trainer, the excitement of operating a more advanced and manoeuvrable design such as the Venus 40 can’t be beaten. I hope you will accept the challenge and tear up that awaiting airspace before too long!
So, is that it as far as ARTF model assembly and flying technique is concerned? Well, there’s always that very first sport-scale project, I suppose. Hmm…now there’s an idea!