Concours d’elegance

Scale flight 1

Scale flight 2 scores 17-8-08

Scale flight 2 points

Points total

Phil Beard

9

10

2nd 25

9

28

Glenn Woodford

10

9

3rd 22

8

27

Peter Kessell

8

7

4th 18

7

22

Chris Hague

7

-

1st 26

10

17

Roly Nix

6

8

-

-

14

Dick Hanley

5

-

-

-

5

Name

Concours d’elegance

Scale flight 1

Scale flight 2 scores 17-8-08

Scale flight 2 points

Points total

1.

Phil Beard

7

9

1st 26

10

26

2.

Glenn Woodford

8

7

2nd 24

9

24

3.

Simon Cragg

9

10

-

-

19

4.

Peter Kessell

5

6

3rd 18

8

19

5.

Rod Board

10

4

-

-

14

6.

Dave Whitfield

6

8

-

-

14

7.

Ron Bean

4

5

-

-

9

One of our club "models" for 2008 is the Ripmax Tiger Moth ARTF (Simon Cragg reports). It is very similar in construction / ancillaries / fittings etc. as the kits from Seagull / Black Horse. The model has a wingspan of 56" and should weigh about 6 pounds.

Mine took about three weeks to put together and test flies today...the 14th of November 2007.

Starting from the front here is a detailed overview of how it all went together.

I bought a brand new Saito 62a from Inwoods for £115.00. I chose this engine as they had recently come down in price (a lot) and only weigh 470g with exhaust, which is fairly light for this size of the engine. I fitted a 13 x 6 Master K prop and alloy domed prop nut. The Saito comes with its own plug, and I am using Irvine Sport 5% fuel.

I used the tank that came with the model, but elongated the hole in the bulkhead to lower the tank slightly to get the centre of the tank in line with the spray bar of the carb. The cowl was an excellent fit, and everything lined up very well. However, it was necessary to fit a remote glow as the bottom cowl support obstructs access to the glow plug. For once, I managed to drill all the relevant holes in the cowl in the right place (bar one)!.

I made some new u/c fairings from balsa, as the originals were very flimsy. The u/c and wheels fitted OK, although the grooves for the u/c wires were a little on the large size. 

All the gear fitted in the fuz easily. The only changes I made were to replace the push rods with a snake for the elevator and a closed loop system for the rudder. As I wanted to access the RX Nicad with the model in one piece, I made a compartment just behind the trailing edge underneath the fuz. This also helped with obtaining the correct c/g.

The tailplane / fin / rudder and steerable tail wheel went together with no problems, as did the bottom wing / servos etc.

This is where it started to get a bit complicated!.....The instructions for fitting the top wing centre framework and cabane struts are virtually non-existent, and as this is a critical part of the model I took a lot of time and effort to try and get it right. Here's how I did it:

1. Level the model on its wheels and put a spirit level or incidence meter (IM) on the tail to get it dead level.

2. Attach one side of the top wing centre framework by one screw only to the side of the fuz. obtaining the position as per the instructions.

3. Put a spirit level on the top of the framework (where the top wing would fit) and pivot the structure until dead level. Screw in place.

4 Carefully repeat on the other side of the fuz. making sure it is laterally level as well.

5. Turn the fuz. upside down and carefully mark the position of the four angle brackets that hold the top wing in place. Make sure the wing is square to the fuz. and the tail.

6. I replaced the cabane struts as I thought they were too heavy to have outboard of the wing. The new items were made of three ply and sixteenth balsa. Again, careful measuring was required to make sure the gap between the two wings was equal each side.

7. Once it was all together I elongated the holes in the centre framework to achieve +1degree of incidence on the top wing only. An IM is critical at this point.

I researched the subject of wing incidence, and eventually settled at +1 degree although I am still not sure this is the optimum for this type of model.

I used the fittings that came with the kit for the various flying wires and anchor points, although I used allen bolts and nylock nuts to hold it all together.

The c/g came out as per plan @ 45mm back from the LE on the bottom wing and the model weighed 5 pounds 12 ounces. I checked the c/g 3 times on a computer programme I had just to be on the safe side. It turned out to be about 27% which sounded about right!

Now comes the best bit. The test flight!.

The wind was from the North and gusting 10 mph...so not ideal, but at least if it went pear-shaped I could dump it in the field on the right, (as opposed to the quarry if the wind was from the South West). The Saito instructions advise that after running in, RPM on the ground should be in the region of 9K so that’s how I tuned the engine prior to departure.

As I anticipated there was adequate power from the Saito and the model tracked straight into the wind. Now where have you heard this before: "All that was needed was two clicks of right and two clicks of down and the model flew hands off"? Well, that's more or less how it went! After flying around for about ten minutes to get the feel of the flight envelope, I landed the model on the tarmac. I then made the following adjustments:

1: Couple in some rudder with the aileron to make the turns a bit smoother / positive.

2: Add a small amount of weight to the tail, as the model dropped like stone when inverted. This puts the c/g at about 30% of the total wing chord.

3. Increase the movement on all surfaces. Aileron 1.00". Elevator and Rudder 1.25". 30% Expo. on everything less throttle.

4. I noticed a very slight twist on the tip of the left wing which could be the cause of the slight trim adjustment.

I test flew the model again, and this time the model was much more responsive, with only a slight push forward on the elevator to maintain level inverted flight. The stall was difficult to provoke, and when it happened the right wing dropped very slowly and recovered easily in the normal manner. Again, a reasonable landing although the model tipped forward on the grass which stopped then engine.

All in all, a very successful session. I have glossed over the more mundane aspects of the build and am sure that the model will give me many hours of good flying in the future. I hope you have enjoyed this review and if you have any queries please do not hesitate to contact me.

Simon.

WHIZZA

The second of our club models for 2008 is the Whizza (Chris Hauge reports) The build sequence was straight forward and fairly quick as you will see in the sequence of photographs

3. The tail feathers are equally as quick to make and sand. I used cross grain balsa on the tips (like the wing tips) to reduce the risk of warping.

6. First test flight No. 1a – was not with the above set up and was short – but not too sweet. All my fault! However it did show that even an uncontrolled landing causes very little damage and the Whizzza had the wing glued back on and a more suitable motor installed in no time at all, and you can’t even see the join!

7. Proper test flight No. 1b with the correct control throws and the C of G  at the front of the range stated on the plan produced a smooth take of and a trouble free flight. With this forward C of G I did however need some up elevator trim to fly straight and level. Progressively moving the C of G back has now overcome this.

8. I have now had over a dozen flights and the Whizzza and has lived up to expectations. Easy to fly with a wide speed range, not dropping a wing on the stall – just mushing along going slower and slower and also being able to cruise around at half throttle if you wish. A satisfying plane to both build and fly.

9. There is still plenty of time  to get a kit of parts and join in the fun, either i/c with a .25 or electric with an outrunner.

10. The cost of a kit of parts is very reasonable and the canopy is just £6.

Christopher.hague@ntlworld.com             Chris Hague