Powered by Laser, a gallery thread

[Ron Gray]

Thanks Chris, it does sound nice! General flying wasn't a problem but as you can see in the last vid I was caught out on landing, I should have brought her down before I did as the area in front of the windsock is very turbulent due to a hangar to the left of us!

[Jon H]

Cant beat a nice Hurricane, I like!

[Ron Gray]

After the demise of the Hurricane shown in the vids above, here is a very poor vid showing its replacement powered by a Laser GA 30. Watch for the fast right to left fly by and hear the GA revving (19x6 prop, really need to go up to make it sound better). Plenty of power as can be seen by the climbing. A wheel fell off hence the nose over at the end.

Edited By Ron Gray on 05/01/2019 11:51:59

[Adrian Smith 1]

Nice model, Ron. Sounded quite windy, but expertly flown. Is that an old aerodrome runway I see?

[reg shaw]

There seems to have been a few nice warbirds posted recently, so I went rooting amongst my pics. I don't have any glow motors anymore, let alone Lasers, but eagerly await the introduction of Laser petrols. Here's an old one of a 1/5 scale Bf109 E-4 in Gallands colours. Powered by an ancient, even then, Laser 150V. It needed onboard glow to keep one of the two fires lit but sounded fantastic as it would reliably cough and fart on one but would always come back in. It was fully enclosed, rockers removed and the last exhaust stub each side was the Laser exhaust, the other 5 each side was cooling air out. I really tried to go to town on this one, working auto slats, radiator shutters and the canopy and its windows opened. I'm going to root some more as I've done a few Laser powered models over the years. How soon til the petrols are here (tongue in cheek!! When they ready, they ready!!)

Ian.

[Jon H]

when will camera/phone manufacturers start making at least some effort to control wind noise? its one of my pet hates!

Anyway, nice work Ron. Good to see Harry 2 in the air and the GA30 certainly seems to have no trouble hauling it along. Fingers crossed for better weather!

Reg, you got it, when they are ready

[Ron Gray]

@Adrian - yes it was a bit breezy and cold! The site is an old WW2 B17 airbase and we’re lucky enough to have both a hard and grass surface to fly off. The latter came in handy on the first flight as just on take off a wheel fell off which meant that I had to belly land it, I often wondered if the big under wing cooler would survive a landing and so it did, the only damage was the small oil cooler which broke off but was stuck back on again for the remaining flights.

[Ron Gray]

@Adrian - yes it was a bit breezy and cold! The site is an old WW2 B17 airbase and we’re lucky enough to have both a hard and grass surface to fly off. The latter came in handy on the first flight as just on take off a wheel fell off which meant that I had to belly land it, I often wondered if the big under wing cooler would survive a landing and so it did, the only damage was the small oil cooler which broke off but was stuck back on again for the remaining flights.

[Ron Gray]

@ Jon - totally agree with you and the vid that I’ve posted I had to edit the audio track just to be able to publish it! Unfortunately smartphones are generally rubbish at sound recording unless you know exactly where to put your fingers to prevent wind swirl around the mic. And even then they’re not that good. The best way of doing it, if using a smartphone, is to record the sound separately using a sound recorder with a decent mic. These can be placed on the direct line of flight, or closer to it and decent mics can be more easily shielded to prevent wind roar. The sound track can then be mated to the vid.

[Ron Gray]

HK 30cc Sbach, powered by a Laser GA30

[Jon H]

Nice one Ron. has it flown yet?

[Ron Gray]

Oh yes! I posted some more details in the new models thread but just some more details. Engine hadn’t been run for a few weeks but started after about 6 turns on the electric wrist. After a warm up tested the revs and pulling 7500 with an APC 18x8 which did seem less than I got from it when it was in the Hurricane (my notes taken then showed 8000 with the same prop but it was a lot colder then). First flight required a small amount of up and a small amount of aileron correction to give hands off level flight. Vertical performance was pretty good, not 3D but I don’t want that otherwise I would have fitted one of my DLE 35s, but more than enough grunt to give big loops and stall turns. Slight engine hesitation when performing Immelmann so may need to double check things out but nothing really to worry about. But the sound, oh what a joy to hear it performing, no harsh 2 stroke here!!!!

Took it up for a second flight but in the down line on exit from a split S I noticed a marked nose down which required quite a bit of up to counter. Thinking that something had come loose I managed to land and found that one of the servo arm’s splines had failed! Lucky me that it didn’t cause more of a problem! Fixed that but then when I restarted the engine and ran it up to full regs I noticed that the elevator halves were waving at me in opposite directions! Couldn’t find anything to cause this so didn’t fly again, any advice re this last bit?

[Ron Gray]

I should have added that it was one of the elevator servo arms that failed, not clear from my previous post!

Still don't understand why only the elevator servos were affected by the high revs interference problem, maybe because they have the longest cable run and are running in parallel with the ignition power lines. All battery power lines run on the opposite side of the fus to the servo cables so no induced EMF potential issues (I think!).

[Jon H]

that could have been nasty. Could the elevators be confused by a vibration resonance? i saw this the other day with a model at the field where the throttle servo went mental at a certain throttle setting due to harmonic vibration

[Ron Gray]

One of the guys did mention harmonics but how do I stop it?

[Denis Watkins]

Even though it is balanced Ron

Try the prop 90° from where it is now, and retighten

[Jon H]

one of the issues with modern style models built from a spider web of laser cut ply is that they are hopeless as absorbing vibration and resonate like crazy. it might be a faff, but you could try mass balancing the control surfaces as they will then have neutral balance and will not want to vibrate

[Ron Gray]

Thanks guys. I will certainly try and mass balance the surfaces but it surprises me that both elevator halves started waving at the same time in opposite directions. I would have thought that the chances of this happening would be quite remote as this is a mass produced model, so the chance that the mass of each half is equal would be small? Good point about the prop, I certainly didn't see any of this on the first run up and flight so it could be that the prop has slipped slightly.

[Frank Skilbeck]

Maybe not, if it is the torque fluctuations from the engine that will be a twisting motion down the fuselage so the elevator halves will go in different directions on each pulsation?

[Ron Gray]

I’ve spent a bit more time on this now. I’ve turned the prop round several times, no difference, on high revs the elevator halves are still fluctuating. I’ve tried a different prop but with this one on the engine pulled 500 fewer revs so didn’t have the problem. I’ve now noticed that there is an occasional misfire when at max revs so my thinking now is that the CDI or kill switch are the culprit. Easy to swap out the switch, more work to change the CDI plus I don’t know if I’ve got a spare one. Oh, I also put a ferrite ring on the switch to Rx connection, no difference.

[Ron Gray]

And the culprit is/was.............the CDI unit. As nothing else fixed the problem I took a unit off another ‘plane, changed the plug cap to suit the GA and replaced the one on the Sbach. Fired it up and once warm ran it up to full revs and saw no surface movement anywhere and no miss firing. So all ready to fly tomorrow.

Regarding the props, did try a Menz 18x8 but it only pulled 6900 against 7500 for the APC (standard). I’m going to take the Menz and an APC 18x8 wide plus a 17x8 and a 17x6 just to see how they perform.

[Jon H]

I was sent these by a customer and thought they were worth sharing.

They are a pair of Avia FL3's built by Franco and his friend Giulio in Italy. Laser 90/100 for power and i would say they really look the part.

[ASH.]

Thanks for sharing Jon, they really do look the part. Excellent pictures.

Never heard of the Avia FL3 before. Any specs on the model?

 

Edited By ASH. on 29/08/2019 17:05:09

[Former Member]

[This posting has been removed]

[Jon H]

Posted by ASH. on 29/08/2019 16:59:50:

Thanks for sharing Jon, they really do look the part. Excellent pictures.

Never heard of the Avia FL3 before. Any specs on the model?

Edited By ASH. on 29/08/2019 17:05:09

Its a new one on me as well! I will ask Franco for some more details.