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Member postings for Chris Walby

Here is a list of all the postings Chris Walby has made in our forums. Click on a thread name to jump to the thread.

Thread: Seagull Hurricane Laser
19/06/2020 15:35:10

All the best ARC and please keep us informed as to how you get with the build and flying. Any questions please post as we all want to help if we can, wink

Thread: la.40 in an Acrowot artf?
18/06/2020 17:55:29

I have a Laser 70 in my Acrowot and highly recommend the combination. No major modifications, no lead and C of G spot on + flies and sounds really nice.

PS Was there not an issue with LA (46's so assume other sizes) where the plastic engine case leaks causing poor performance? Worth a check first.

Thread: Post A test model
18/06/2020 12:26:49

Thanks guys, really helpful there with lots of good ideas and I'll go away an do some research. I am sort of trying to look at this through "young" eyes as to what meets that expectation while proving practical/cost effective.

The rational for foam was its easy to repair and I accept balsa models might be better (did my B with a BH Speed Air electric...then Laser 70 powered) but can entail more repair skills following a mishap. I also agree that the extra mass of the model is an important element to learn. I think improved performance with a foam ARTF is a good stepping stone at this stage.

Cheers guys, most enlightening.

PS - ooorr I like that SLEC fun fly....

18/06/2020 08:31:16

Honest not a question from me, its for another person, really wink

Seriously though, there is a young lad who will be taking his A test shortly (COVID rule permitting) and will no doubt take little time to fully explore the flight envelope of his current Carbon Cub Z (no giro or stab) nice trainer, but a bit of a wet lettuce in performance.

I thought of suggesting the Ruckus, but to be brutally honest after just a few flights he'll be beyond that.

Needs to be ARTF, foam, about 55 span...electric, possibly mid wing.. something tame, but up the rates is lively!

Suggestions please?

  • Chris Foss stable? Wot4 foam-E
  • Cougar 2000 (ok not foam)
  • Eflight T28...too complicated UC that's a bit fragile

There must be other stuff out there?

Thread: Laser Engines - Technical questions
16/06/2020 17:22:28


I have to disagree on a couple of points.

One principle reason why multi cylinder bikes give more power is that the pistons and rods move through a shorter stroke (see above for a 61 its bore is 26 & stroke 18, looks well over square to me) so for the same piston speed you can increase rpm (agreed), and as we all know, revs=power (only sort of, HP = Torque x RPM ). Lighter pistons (can be achieved with lower crown to gudgeon height, but not by making the stroke shorter if you rev it harder), shorter flame front, smaller required gas flow per cylinder - they all add up but mostly it's down to rpm. (you can manipulate power figures by just making it rev harder, but it does not make the engine perform better in real life).

Very short stroke high revving engines need to be kept in their power band normally by changing lots of gears! But you can't do that with a prop if you don't have enough torque to achieve peak power.

One of the fastest bikes I ever rode (500cc Weslake mk1) could have its clutch dropped in one gear and accelerate to just over 86 mph in the same gear and it was still pulling! Torque rules in my book laugh

Thread: Acrowot landing gear
15/06/2020 12:13:54

Harsh there ED!

I take the point about some very demanding flying fields and agree with U/C only designed for tarmac as being poor.

Landings.. well flying as well are not my strong points, but I have not removed my U/C yet. So why has it lasted this long?

How about Tundra wheels, plenty of give in them.

15/06/2020 10:42:39

The plate is free floating and allows people to access the end of screw remains so you can get them out.

While I think this is a good idea for some models, I am at a total loss with my Laser 70 Acrowot as it has really nice landing characteristic. Fly it in, blead the speed off and once the energy decays off let it settle down.

It will punish you if you bounce it or have too much air speed, but so do other CF designs and its not his fault!. I think the problem is when people put 80, 90's FS in there, add a load of lead to get C of G and end up with higher wing loadings, hence a bit of bite.

Could be good practice for manhole cover flying or one of my home builds...wink

Edited By Chris Walby on 15/06/2020 10:45:02

Thread: Powered by Laser, a gallery thread
15/06/2020 09:56:07

Very nice Ace, looks the business and any landing without a nose over or the U/C somewhere on the runway is a winner!

Thread: Laser Engines - Technical questions
15/06/2020 08:08:33

I think its a matter of scale!

Very small engines are very powerful for the cubic capacity, but the more cylinders you add the more friction/complexity introduced.

Power tends to be inversely proportional to reliability unless you engineer issues out. If Jon made a very powerful engine and announced that every few hours it would need major "factory" service some people word whinge and others ignore him and run them to destruction and then whinge some more.

Jon has to take into account that there is a very wide spectrum of operator skills some follow instructions, some don't and some clearly think they know better than the manufacturer.

For me the balance is completely spot on....Reliable, easy to operated, reliable, hard to wear out and reliable.

IMHO a V150 would be more powerful than a single 150, but a V4 150 would be more powerful again..fancy setting that up?

PS Power is a bit meaningless as multi-cylinder engines are heavier and its where the torque is produced that is important...perhaps time for another question?

David, example what's the red line on a sports Japanese multi cylinder +14K + loads of electronics to manage power valves etc, radiators.  I like, start fly, refuel, fly and the only thing to worry about was did I charge my glow stick!

Edited By Chris Walby on 15/06/2020 08:15:09

Thread: Battery position
14/06/2020 15:27:25

My Acrowot has a Laser 70 in it, no lead and the RX battery goes underneath and in front of the tank. I use a 3S800 lipo and an external electronic switch/UBEC.

I made a hatch up out of the weird bit of fuze that can be cut out for electric or something (couple of dowels and hatch catch).

I started off with the battery in the fuz above the wing and lead in the cowl, but after moving the C of G to the published figure (started forward), I just moved the battery forward and dropped the lead.

They fly super nice, hope you are impressed with yours.

Thread: Hatch Catch
14/06/2020 14:01:45

Tosh, The neater smaller brass one is spring loaded.

Seagull do a neat trick where the canopy slides inside the cowl, then drops down and locks as it slides back. Its stopped from moving forwards by a magnet. Really quick to release and very little chance of it coming off in flight.

Thread: Need a new fuel pump (glow fuel)
14/06/2020 06:46:47

Am I missing something? I can see the convenience of electric powered fuel filling and perhaps I am a just miss guided or overly concerned about tank capacity?

Most if not all electric flyers at our club check their lipos before and after flight to see what they have used.

I count the turns to fill a tank at the start of the day, fly and once back in the pits refill and count the turns to see how much I used for that flight.

Maximising flight time with a bit of spare for a go around seems prudent, dead sticking with and empty tank just seems unnecessary risk to wallet and safety of others.

PS - My second hand old grey hand pump needed a strip and clean three years ago...has worked ok ever since. might take a couple of turns to prime sometimes.

Thread: Things that have dropped off in flight
12/06/2020 07:21:28

Sorry to say Devcon1 and Martin, things that are intended to fall off don't count cheeky

I never cease getting that heart stopping moment when we launch the Vulcan just before the bungee line drops off having it lawn darted its self in due to non release.

Dolly the right way around helps as well, crying



11/06/2020 18:38:39

Just for a bit of fun could people own up or recount of others misfortune over the years with suitable saves from the bin liner.

Mine from this week was approaching the flight line and lowering the U/C. I was expecting to see gear down and locked but was treated to the oleo and wheel descend to the ground from one nacelle! No major panic or damage just a gear up landing ensued.

Surely that can easily be bettered?

Thread: Extra Slim Twin
11/06/2020 18:24:09

I'll try flying vertically slower and see if that has an effect as I have a couple of degrees of side thrust set on both engines.

I won't be surprised if one engine was running faster as its well over propped (for the noise test) and both engines are from different sources.

Perhaps with Dave's engine it will head in the other way! In reality I am not too fussed as I don't think the design was intended for much straight flight in any direction!

Paul, I could not see the point of the cheeks...Plus the way these things shake I would like to keep a check on the Nyloc engine mount nuts! Embarrassingly enough having my U/C fall off, but a complete engine would get to the club newsletter.

09/06/2020 21:02:04

Good to see another EST taking to the air!

I must admit I thought I had dropped a clanger when I tried to get it in the car....and I had to take everything out, but today it was IC twin day for me ! EST, Dual Ace and the SG Mossie (later two Laser 70 powered) and they all fitted in a treat.


As an observation mine climbs vertically to the left unless I hold a bit of rudder in so got sure if a trait or I have one engine out performing the other. My OS LA46 are many hands old and from different sources hence no idea of the internal condition.

They fly very nicely and I worked up to mid rates today, but bottled out of the centre flap or rudder to throttle mix!

But it does knife edge very nicely laugh

Thread: Scratch Build Twin
09/06/2020 17:30:24

Just out of interest Jim what is the estimated wing loading? Having asked that I have some models that have high wing loading and fly very well if you give them the respect they are due.

Thread: Forum members' new models: Let's see them.
08/06/2020 17:52:20

Nice MBB-Rockwell X-31 you have there, best of luck with the maiden. Quick question, is the canard fixed or does it move? If so what have you got in mixed into?

Bob I like your Panic and from just finishing and flying my translucent Extra Slim Twin can you comment on recognising the orientation of yours as mine can be really hard with sun shining through it?

Thread: Battery ejection - bad crash
05/06/2020 13:00:56

I have a WOTs WOT where the battery is taped to ply plat located by a Nylon screw on a keyhole shape hole.

At the top of a vigorous stall turn and vertical pull out I noticed the lipo hanging from its EC5 connector. As I gently tried to circle and loose height all was going well until the model was about 25ft off the deck. At that point the lipo disconnected itself and with a now massive rearward c of g the glide did not last long. Damaged but repairable and now use one of these to stop the plate sliding.

ww battery plug.jpg

Thread: From DX8 to DX8 G2 or DX9
04/06/2020 08:16:48

Hi, I don't glide (too fat! actually nowhere to fly and like powered FW), but have DX8 gen 1 and DX8 gen 2 for about 6 years in total.

I don't have and have never used a DX 9, but I think I would go for a DX9 gen 2, why:

  • The DX8 gen 1 and DX gen 2 model files are not transferrable, so you have to reprogram all of your models back in.
  • The DX8 always seems a little bit of the poor relation compared with the DX9 in both the gen 1 and less so for the gen 2 versions.
  • The DX9 gen 2 has more functionality and I think would be better long term
  • As mentioned the AT8010T is a bit of a brick

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