Derryonline

Seagull Boomerang maiden flight and magnetic trees

// June 29th, 2009 // No Comments » // Uncategorized

I took my newly built Seagull Boomerang out for it’s maiden flight a few days ago, before I even got out of the car I’d attracted a few onlookers, one of them even kindly carried all my gear onto the field for me.

After checking for any loose bolts on the control horns, that the prop. driver nut was secure, all the electrics were working as they should and the control surfaces moved in the right directions I lined her up and gave it some beans, she took to the air within about 20 yards and almost immediately started looping, not good, I hadn’t used enough elastic bands on the wing so I fought her back down, added a load more and tried again, this time was much better and it settled into circuits with no problems other than a few clicks of down trim.

One thing I hadn’t thought of was the length of the field I was landing on, because of the prevailing winds I have about the width (not length) of a football pitch to take off and land from and each landing is cutting it very fine, in fact, on one landing I was sure it was going to overshoot and hit the bottom of a tree so I throttled right up and tried to get some height quickly, not a good move with a large trainer, it landed in the tree, right near the top, completely out of reach.

Luckily a couple of (very kindly) onlookers helped me out, before I could think about how to get it down one chap shimmied up the tree, climbed out on to the branch and handed the model down, to my amazement other than the odd scratch in the film there was absolutely no damage.

I took her up for a final flight just to check everything was as it should be after the accident and after an uneventful flight landed again, almost overshooting yet again.

I looked for some advice from RCHangout.com and I’ve got some things to try out to see if I can slow the Boomerang down more prior to landing, one is to get an 11×5 prop. rather than the 10×6 I’m using, another is to reflex the ailerons up a little to cause more drag and the last resort is to add an extra aileron servo to dial in flaperons, not keen on this option as it requires some surgery to the wing.

Cowboy builders

// June 22nd, 2009 // No Comments » // Uncategorized

Had a knock at the door this morning and was informed that “we’ve just hit your car”

With this …

Still waiting on their insurance details, which I’m not confident I’ll receive as the MID (Motor Insurance Database) claims it’s uninsured.

Electric starting vs. flick starting your glow engine

// June 12th, 2009 // No Comments » // Uncategorized

I’ve read on a lot of site’s that electric starters are essential for glow engines. This is of course absolute rubbish. A poorly primed or damaged engine will only suffer (more) damage by trying to force it to start with an electric starter. A well looked after engine will start after one or two flicks if it’s primed properly.

I’ve paraphrased from a popular UK RC magazine for this priming procedure.

1. Fill your tank (obviously)
2. Open the throttle on your transmitter to full
3. Either choke the carburettor or exhaust with a finger
4. Wind the prop by hand anti-clockwise until the fuel reaches the carburettor through the fuel uptake hose
5. Give it 1-2 more turns to draw fuel into the carb. itself
6. Unchoke the carb./exhaust
7. Throttle back to 1/3 – 1/2
8. Attach glowclip (make sure you’ve checked your glow plug is working ok and that there’s sufficient charge in your glowclip battery)
9. Turn the prop. clockwise until it reaches the top of the compression
10. Give it a good flick clockwise (yes, they normally turn anti clockwise but bouncing off the compression is far easier).
11. Your engine should start on the first or second flick. (hopefully, always works for me).
12. When you’re finished flying, remove the glow plug and open the throttle (when the engine is powered down obviously) and add a few drops of after-run oil, give your prop. several spins to work it in.

For helicopters you generally don’t have a choice BUT to use an electric starter so the above doesn’t apply.

Every engine will have it’s own peculiarities and will probably need slightly different priming techniques but if you look after your engine then you’ll never need to use an electric starter.

Seagull Boomerang (.40 - .46 2 stroke)

// June 11th, 2009 // No Comments » // Uncategorized

This is my first IC trainer, and my first ARTF model. I wasn’t sure what to expect with ARTF’s but as it turns out it was fairly easy to build, with just a few niggly problems which aren’t really down to Seagull themselves.

I started by reading through the manual, after about 4 pages I threw the manual in the bin as some of the instructions were spurious at best and a bit of common sense and the bare minimum of DIY skill is all you need.

I started the actual build with the wings, there’s an aluminium spar that first through both wings, I used 30 minute epoxy resin on the spar and the wing joins and clamped them in position, half an hour later, perfectly assembled and lined up wings .. easy!

I then moved on to the horizontal stabiliser. I measured it and drew a line in felt tip exactly halfway across, mounted it in the fuselage and drew round the fuselage to get a guide to cut the film away. After removing the film I glue it into place with more 30 minute epoxy.

On to the vertical stabiliser, the film has already been removed ready so it was a matter of applying some more 30 min. epoxy, remove the film on the fuselage covering it’s holding slot, getting a square and lining it up in relation to the already aligned horizontal stabiliser and then keeping it secure while the glue dried.

Next was the undercarriage, simply slot them in and screw them down, connect up the steerable nosewheel clevis to the push rod, slide the nose wheel in with the notch to the front and screw it in.

Penultimately on to the radio/servo installation, very easy, simply screw down the ones needed in the fuselage (elevator, throttle, rudder/nosewheel) into the plywood tray and for the aileron’s you epoxy another small plywood tray to the centre of the wings then screw down your servo. You can mount the receiver pretty much anywhere you like and there are two already cut mounting holes for a switch harness on both sides of the fuselage (mount the switch harness on the opposite side of the silencer so you don’t end up covering it in fuel)

And finally on to the worst bit of the build, mounting the engine.

I’m using a Thunder Tiger Pro 46 2 stroke, this is slightly too large for the supplied glass fibre engine mount and will warp it somewhat, the screws supplied in the kit are also very weak wood screws which were far too large to fit through the motor mounting holes on the engine. After stripping a couple I ended up getting some machine bolts/nuts from a local DIY store, I removed the motor mount, marked up the holes with felt tip with the engine mounted and drilled them out, then bolted the engine down and rebolted the motor mount to the fuselage. I’ve no idea if the side/down thrust offset is correct but I plan to use some form of spacer behind the motor mount if need be to get the offsets right (if need be, it appears to have a small amount of side thrust already built in).

That’s about is, for my first ARTF I’m reasonably pleased with the quality and ease of assembly and I know what to expect from my next one. She’s still waiting for her maiden flight however, I guess we’ll see how well it’s put together when it’s in the air.

Thunder Tiger Pro .46 engine problems

// June 11th, 2009 // No Comments » // Uncategorized

Beautiful sunny day today and I decided to try and run my engine in, a Thunder Tiger Pro .46 2-stroke. I primed it properly and on the first flick it almost turned over, I gave it another flick and it’d become very loose and the prop was spinning while the engine itself wasn’t turning over.

I unscrewed the spinner and noticed the nut securing the prop. was loose, presumably I hadn’t tightened it enough. I tried to tighten it but as it turns out the threads in the nut were sheared. I checked the manual and it stated I needed a 1/4inch “UNF” nut, at the time I had no idea what UNF meant and assumed it was just a normal M6/1/4 inch job, turns out it’s not, it’s a completely different thread.

I tried Maplins, Halfords, B&Q, the local builders merchants, every motor factors place in the area all with no joy, however, the last motor factors place I rang recommended a local precision engineering company who sell to the public and after a quick scoot down there I got a pocketfull for 50p.

So, if you strip the threads on crankshaft nut, don’t bother with your local DIY shops, try a local engineering firm, or look online, just make sure you check the manual for the exact requirements.