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World Models Spitfire 60


Tim Flyer
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Cheers Chaps. I think I will go for the Ally Spinner Idea as I never like "non functional weight". I will also move the retract battery forward and that might just get me there.

I did go for a fly today with the Wot 4 XL. Was so cold i just managed one flight and was very very muddy. I'm pleased i put the water resistant wing servos in!

Hopefully will fire up the Laser next week when the pint has hardened

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  • 2 weeks later...

With such an awful weekend for flying , I managed to finally get it all finished.

I added the 3.5inch metal spinner bought from just engines, moved the U/C battery a bit further forward and epoxied just 30g of weight into the front of the cowl to get the balance spot on. As I had already "front weighted the plane" by reinforcement up front i didn't need to add much weight.

I also ran up the engine. First of all I discovered my first "...up" on this model which was getting the vent and filler lines the wrong way round. After messily filling the tank the fuel all syphoned out. I soon saw what was going on as I had swapped the kit tank when i built the plane with a nicer clear Sullivan one, which was a better shape. I soon swapped the lines round on my brass tubes I had glued in the engine bay, a simple job.

Anyway here comes the good bit!! I also ran up the new Laser 80.
After blowing a bit of fuel into the engine to prime it(a bit of silicone tube on the vent tube used for that) the engine started almost first flick... no electric starter needed! I bought some 5% Laser fuel when I bought the engine . It seems good value at about £15/Gallon.
I have only heard a laser engine once before and the noise is magic!! The tick over is very low and lazy and full throttle very strong. They have a unique sound. IMHO are much quieter than many of the electrics we have at our club, and sound like a "proper plane" rather than an over-powered hair dryer. I did the usual throttling up and down and finally leaned it in a bit. It seemed to run for nearly a half hour on the 12oz tank. The only thing I think I might need to do next is tune in the idle setting as its quite rich. I might leave that until it has been flown. Anyway I can't wait until the spring and the ground firms up and I can get this plane into the air.

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Cheers Ash. Thanks for the encouragement. As an overall view so far i would say that it is a very good value for money kit.
As you mentioned the covering isn't great, but I managed to sort that out with paint, better decals, and a bit of cyano in places. I developed a "new technique" for sheeted areas with loose covering. I made a very small cut in the covering with a scalpel and held the small cut open with a pin whilst dropping a bit of thin cyano it then spreads out with capillary attraction. That seemed to work well and leaves few marks.

Once I give it a fly I will write a report up here. Unfortunately our runway is very boggy at the moment so it might be a couple of months. I will soon be starting a glider build, to be towed by my trusty all weather WOT 4 XL. Happy Flying All .. Best regards Tim

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Nice update Tim. With you on the laser 4 strokes, great engines and much more enjoyable than any electric ticker. I have a complaint though, where are the pictures!?

I need to start a kit soon but am building a new bench at the moment. Hope to finish that this week and then decide what to build.
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Hi Tim

I am very sorry your engine didnt start first flick, 2nd flick is ok but 1st is what i aim for!

I had a look through your build photos and your tank a smidge on the high side so i am not surprised the slow run needs leaning off. Because of your tank position not being ideal the engine MIGHT get stroppy with negative G at full power so no outside loops! The best procedure for slow run tuning is to set the main needle for max rpm (should already be there if you read my running in instructions ) then come back to idle and stuff the throttle fully open as fast as you can. If the engine picks up lean the slow run 1/8 turn and do it again. keep repeating this until the engine bogs down and wont accelerate, then come back rich a tiny bit at a time until it is perfect. Then double check the top end and its job done. look for a stable idle rpm around 1800-2000rpm. if you get this it indicates a good setting.

You can also check out this video i did a while back. Its a 150 totally out of tune with both needles very rich. I then run though this tuning procedure. Let me know if it helps

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Oh, and for your general interest this is a 360v receiving its test run at the factory. This engine was brand new and had never run prior to this video being taken. As you can see, the idea of running engines in for hours and hours in the garden is long dead with a Laser. Just get on and fly

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Aha very informative . Thanks John. One thing I noticed is you use a backwards flick to start them? I was flicking clockwise. I'm no expert in 4 strokes and just thought I had to flick them in the direction they run? My OS 120 2 stroke does sometimes run backwards! With the laser I will dial the tick over in as you have shown . I didn't want to do too much in the garden as you said , and was really just checking the tank position was ok. It seems to run very well with it and once I get to the field I will re tune with cowl on then all done and fly😊

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No worries Tim, just remember that a few minutes taken to really set up the engine will pay off in terms of reliability, fuel consumption and the mess it makes. Not to mention power!

As for the backflick, i use this method as you are likely to get bitten if you dont. When the engine is primed if you flick it in the correct direction it will most likely fire long before TDC and kick backwards. This is why the end of my starting stick in the video is so chewed up! But, you can exploit this by flicking the engine backwards against compression. It will fire before it hits TDC and rebound in the correct direction. It will then go through an exhaust stroke (clearing out the cylinder) and then intake the fuel it needs from the carb. This wont work when then engine is hot mind you but works fine when it is cold.

If in doubt or you cant get to it to prime, just go for the electric start

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Thanks again John I will try out the back flick!

I will certainly spend the time on the engine to get it well sorted. I'm a keen "piston head" and pride myself on reliable engines & will soon have the tick over dialled in.

It will be nice to finally keep the electric start in the box

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Thanks for the post Glenn. Sorry for late reply as we have been out for half term holidays. The easy flying is very encouraging and the plane looks very nice. Your field looks in good shape too. I notice you do not use the undercarriage doors. I also decided not to use them as they could easily twist on the runway and foul the retracts, and missing them wouldn't be very noticeable in the air. Our club patch is still a bit waterlogged as we are in Hertfordshire and the soil is full of clay. We will soon have the pits area surfaced with a properly drained gravel layer so that will be a big improvement from wellies and mud.

One question I do have is how much up elevator you use? I have put a bit more than the recommended as i was worried about potential nose-overs on the runway. I put a bit more up elevator on my BH Chipmunk too and thought this may be similar .

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Beware Tim, dont use too much elevator or the model will be uncontrollable. Most warbirds have much more sensitive elevators than sport models and i would typically expect to use less movement than the instructions suggest. I also would not use any expo either.

What i would do is use two control rates. one that is slightly above the recommended and one below. That way you have a safe place to hide if the rate is too high.

To give an example, my 80'' La7 has a very sensitive elevator and i have it set so that i need the elevator stick back to the stops in order to recover from a loop. It sounds extreme, but it makes the model much more docile and much easier to control accurately.

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  • 1 month later...

Hi all just thought I would update after taking the Spitfire on its maiden flight. I set the rates up just as instructions plus had a low rates spit hot just in case. Anyway the good bit: the model flew very well and it sounded excellent with the beautiful but still relatively quiet noise of the laser 80. Rather than sounding like a petrol strimmer as many of the fashionable 2 stroke petrol engines seem to it had a lovely deep note in the air. The motor hardly vibrates at all . After a bit of trimming I started doing circuits an it was certainly a nice docile plane. I tested the flaps which I had mixed with bit of down elevator and they were about right. I did a number of passes then tried for a landing after about 12 mins flight. Silly me! I had her coming in nicely but didn't adjust properly for the cross wind. That resulted in me yanking the rudder at the last minute and the plane dropping a wing and hitting the ground 😒. I let my nerves get to me and should have just pulled out and come in again . I was too keen to bring her in! Anyway . The damage isn't too bad (just wing boot area and rear fuselage and minor wing damage) and will hopefully get it repaired over the next few weeks. Luckily the runway was soft!

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Hi Jack. The strip isn't to bad and could support th Spits weight despite rain on Saturday. It's still a bit soft but dries out quite quickly now the spring is here. Yep a shame but could have been worse. I'm pleased it flies ok and am now finishing repairs to the Chipmunk. Will be sensible next flight with Spit and wait for a day with straight on wind!

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  • 4 weeks later...

Just thought I would update the post following Saturday's successful "dawn patrol" flights. I decided to go out and take advantage of light wind conditions first thing. I will post a couple of photos later . The damage from the crash landing on the maiden flight took a bit of time to fix . I replaced the whole wing retaining bolt unit cutting out the old cracked one and I replaced the fixing with two 6mm nylon bolts rather than the kit supplied 3mm steel bolts. I also had to repair some of the rear fuselage , which I did internally using glass matting and epoxy. I also added quite a bit more lead to the nose. I initially thought I would check the balance following repair, but I realised I must have been flying it with a too rearward c of g on the maiden! It seems fine now after a number of checks. Anyway Saturday had a light 6mph wind slightly cross wind on our runway but I decided it was as near perfect as I needed. The Spit took of f and was a joy to fly. Landing with a nice wide approach and flaps down was no problem . The Laser 80 started second flick and was perfect. On subsequent flights I did use the elec starter though as the motor was hot. I am using a 14 x6 prop which pulls well and provides an easy performance envelope . I might try a 14x7 if I'm desperate for more speed but to be honest the 14x6 seems nice for the moment. I'm very happy with this model and the engine. World models must have taken some of the nasty habits out that we read about with some spitfires. It is quite sensitive to elevator movement as I was warned, but certainly rewarding to fly. 😊

 

 

 

Edited By Timothy Harris 1 on 09/05/2016 14:31:07

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