Topical Soaring in 60 Minutes. Are they sure?

Bought for Chinman by Choddy, way back in the mists of time to expand our early modelling experience at Bumpy Green. This glider was chosen over a number of others and has proved itself to be a remarkable flier, in various conditions and situation.

Chinman builds the......

Formed plastic fuselage with motor, propeller & control rods all pre-fitted. Pre-built & covered wing, tips, tail & fin. Control surfaces pre fitted & hinged. Tail fin pre-fitted with bolts to go through the tailplane & fuselage. A good set of instructions.

3/4 channel receiver. 2 mini servos for rudder & elevator. Speed controller (18A rec.) Battery pack suited to the type of flying.

Control horns were fitted to the tail sections and the whole tail assembled and fitted. Threadlock required for the nuts on the underside. Plastic clevices supplied were replaced with metal ones before assembly. Control rods are already fitted inside the fuselage and just need to be fitted to the servo arms. Servos are fitted into preformed slots and secured. They need to placed facing the opposite direction to one another to match up with the control rods. Receiver can be squeezed into the gap in front of the servos if small enough. Otherwise feed it inside from the battery hatch/canopy and position as far back as it will go.

In hindsight (which is always 20/20) I would have strengthened the bolt hole area of the tail. Any rough handling can lead to the tail moving as the holes expand and become slotted. A few trips up the Beacon brought this problem to light. The solution in this instance was 1/4" square balsa glued either side of the tail fin. One idea suggested (after I had glued the wood on) was to use servo mounting ferules in the screw holes. Painted or covered 1/4" triangle fillet would look a lot better.

The canopy latch broke off before I had even finished balancing as I was taking it on and off the move the battery foam around. A large piece of glass tape was used as a hinge on one side. It is almost transparent when pressed down properly. Another large square is used to stick it down on the other side. Folding the corners over and sticking them to the tape makes it easier to peel up when you need to change the battery pack. The battery fits right against the motor and I used a double neoprene pad between. It needed to be fitted quite far forward and extra weight added above the motor to get the balance correct.

With 15 minutes on the Protech clock still to go it is almost ready. The battery is fitted and all controls checked and trimmed. Time to fix the wingtips on.

The near 1.5 metre Dihedral tip wing is supplied as 3 panels. The centre section and a left and right wing tip. Aluminium tip braces are pre-bent to the correct angle for the tip to fit and align with the wing. Clear tape is used to secure the tips in place, across the top of the wing with about an inch or so around the leading and trailing edges. At just under 1480mm it can fit into most cars without dismantling and could have the tips epoxied on permanently. The leading edge dowel fits into a precut hole in the top of the fuselage behind the canopy. This may take some persuasion and can become a sloppy fit if rough handling enlarges the hole.

Another fix was required after a fast landing popped the wing dowel out. This was epoxied back into place and some glass reinforced tape placed on the leading edge to add some strength to the split balsa of the leading edge. A balsa block was shaped and fitted into the top of the fuselage so the wing dowel could slot in easily. This was due to the plastic of the fuselage starting to split after the fast landing.

With the wingtips fitted and everything secured and balanced a trip to Bumpy Green was in order. An Alpha 180; almost like the Topics big brother: decided to join the fun. A final control surface and balance check, secure the hatch and test the motor. Good job this was done, the spinner flew off and vanished under the car. Two minutes of crawling on the floor and a few quick turns of the allen key and we were in business.

CLICK IMAGE FOR LARGER VERSION

A mild breeze was all that disturbed the air, the sky was full of big fluffy clouds to the east but the rest was clear & blue. Motor on and a firm, level throw is all it takes to get the Topic airborne. It is not very fast on the climb but quite forgiving in flight so a gentle circuit to get it's speed up is all you need. Once it has it's breath a little nose up and the Topic begins a good steady climb. Into strong wind the 400 motor and small folding prop struggle, a bit of nose down adds penetration and the minor drop in altitude can soon be won back once the speed picks up. Flying the Topic at around 45 degrees; side to side with long gentle turns into the wind proved most effective as it's airspeed is kept up but it's ground speed is almost none. Get it just right and it almost seems to hover in the air.

A trip to the local slope soaring venue seemed to be the next thing to do. With a bag of food and a camera (which later turned out to have flat batteries) we set off with gliders packed. It's a fair old walk to the top of the beacon and the Topic proved no problem to carry. A subsequent walk on a windy day didn't prove so easy ... More on that another time.

First job was to tape down the folding prop. This can create drag if left to flap around. The 400 motor was disconnected from the speed controller to prevent accidental (and instant) banishment from the slope for using powered flight. The 1100mAh pack is left in as this balances the Topic correctly. It will also last all day long powering just the elevator and rudder. The most gentle of throws is needed to launch the Topic accurately, on the right day just letting it fall out of your hand will see it sail off into the valley without so much as a twitch. Standing above your glider while it flies is quite something. Due to the height of the slope we soar from (some 400ft) flying 50ft below where you stand is quite common as the gliders trace along the slope getting the updraught.

They were right ~ ready to fly in 60mins (ok we'll assume you had ready charged batteries like I did)
A great model, very easy and quick to build. Even without the mods carried out this glider should provide an hour of flight with a couple of spare battery packs along for the ride.
Sloping it you can fly all day on one of the 1100mAh packs and still have enough power for a crafty flight back to the car park.
I would recommend this to anyone from beginner to intermediate, or even the more experienced if they just want something that will fly from a flat field or a slope.

Likes
Good value, quick to build, easy to launch and fly.

Dislikes
Plastic clevices, The canopy catch ...... that's all I can think of.

Next Time
Bungee, winch and maybe even aero-tow launching to be explored and explained next summer.

 

Article by Chinman from Bumpy Green Model Aerodrome
6th November 2001

Comment by Brian Massen on 00000000000000. Rating 4

I chose the Topic 400 as a first model on advice of my local model shop. I found in a good breeze it was difficult to launch. This was overcome by installing a graupner 480 motor. Since then I've never looked back. Brian.

Comment by phil on 00000000000000. Rating 4

great for a bit of evening flying and trying to catch those thermals. great off small sand dunes to catch the sea breeze too. great plane. see mine at www.philsrcworld.fsnet.co.uk

Comment by Paul Robinson on 20040123171114. Rating 5

If you are looking for a lot of fun with a cheap model then this is the one. They fly brilliant we have three in our club and all fly well.

Comment by Jimbo on 20040420183535. Rating 4

Had a bit of a hard time getting the CG correct. I switched to 2150mAh cells (Sanyo HR-4/5AU) and a Graupner Speed 400 motor and I am getting almost 30 minutes per charge. Excellent flyer!!

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