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Member postings for Jon - Laser Engines

Here is a list of all the postings Jon - Laser Engines has made in our forums. Click on a thread name to jump to the thread.

Thread: First Warbird?
03/04/2020 18:03:53

topflite used to do an 80 inch job as a kit but they are rare now. We used to sell 300v's for them and they flew well at 20lbs.

The next step up for ziroli is 92 inch and thats a real whopper! A friend has the old hangar 9 80 inch artf thunderbolt and the fuselage is already like a beached whale at that size.

For the 70 inch version i think belair list some retracts for it. My preference has always been air retracts as i have had/seen way too many problems with electric retracts. I am told by a customer that electron retracts are good, but as they are made in spain i suspect it will be all quiet due to lockdown.

Be aware that you might need 85 degree units and not 90.

And i know its getting ahead of the game but there is no need to go mad on the radio fit either. If it were mine i would use a single subc 6v nimh battery through the beefy switch futaba do. I would then use probably nice quality 3.5kg servos on the ailerons and rudder, perhaps 5kg on the elevator and flaps. To be fair standard futaba 148's would do for rudder and ailerons. Warbird control surfaces are quite small and you dont move them much so there is little need to go crazy with servos.

Just doing some window shopping i would be happy with savox 351 4.1kg (11 quid each) servos on aileron and rudder, then savox 352 6.5kg servos (16 quid) on elevator and those barn door flaps. I already use the 351 as my P39 rudder servo and have 352's in my Sea Fury, Acrowot XL...something else...I dont remember. I just know i have lots of empty boxes in my drawer so they must have gone into something!

Thread: Benefits of the lockdown
03/04/2020 14:54:52

Its only been 2 weeks and already everyone has totally lost it.

For me this lockdown is great as the roads are clear and i get to work without my usual traffic induced bad mood. That leaves room for a different bad mood caused by something else.

Thread: Saito FG19-R3 and small gas engines, how noisy
03/04/2020 14:48:59

The multi cylinder jobs are normally fairly quiet. I have a few OS multi's that run on straight pipes without making too much of a noise. At least, they are quiet enough in the air that no one has asked me to test it on the ground. The deciding factor seems to be the cylinder size. Once the pots are over about 15cc they get too loud and need a muffler,

The only thing to consider regarding the FG19 is that it is not very powerful. Most small radials, and in particular petrol radials, are down on power vs a single of the same capacity. This might be a 120 in terms of cc but its an 80 or at best a 90 in terms of performance while being probably more than twice the weight. My ASP 400 radial is easily beaten in terms of power by my Laser and OS 300 size twins.

Radials are lovely, but be careful with your model choice or you will end up over weight and under powered.

Thread: Laser Engines - Technical questions
03/04/2020 11:59:58

Keith, yep, it would be a whole new front end.

03/04/2020 11:59:25

Posted by Andy Shailer on 03/04/2020 11:39:15:

Hi all, can someone explain and show a picture of the fuel tank set up please for a laser 150, Ive never set one up before, on other engines I always used 3 vents, one to the carb, one to exhaust and the 3rd being the filler, do I simply block the exhaust line, sorry if this is a daft question.

Thankyou in advance.

Andy

P.S Im only stating a 150 as thats what Im going to be using, any size laser tank set info will be grateful

set it up exactly as you would with an engine that uses exhaust pressure but instead of having the pressure pipe connect to the exhaust have it connect to a small brass tube that to glue in the cowl somewhere. The tube needs to point forward so that the prop slipstream provides a slight pressure into the tank. There are no shortage of ways to position the tube but i have pictured some options below.

breather.jpg

breather 1.jpg

03/04/2020 11:25:35

yea the pump will need to sit on the back of the case in a petrol version. I would be happy with a glow prototype for now though.

03/04/2020 10:39:13
Posted by Dirk Witvrouwen 1 on 03/04/2020 09:36:16:

And Jon, don't forget a stylish back-mouted integrated starter for the radial 😁

No room for that, the supercharger and fuel pump are in the way. Its dead weight anyway

03/04/2020 08:27:33

Sounds like a plan.

Radials for all!

I also think one of the first things i would do is make a reduction drive. Get propeller rpm down for much reduced noise. I already have the design done. It would fit our 100, 120, 150,155,160v, 200v, 240v and 300v with only one component change needed per engine and would allow a 200v to swing something like 22x14 3 blade or 24x14 2 blade at a gentle 4400rpm on the prop. Loads of thrust, nice and quiet.

Oh yes, it also would not make the engine more than a few mm longer than it currently is, and could be retrofitted to old engines.

Would be kinda cool i think.

I best keep dreaming.

02/04/2020 23:07:52

OHC engines are too tall

As for an inline twin i already have 3 drawn up are ready to manufacture as well as 3 other things.

Not that it matters, the drawings for my radial were finished about 8 years ago and nothing has been done

02/04/2020 17:35:06
Posted by Bucksboy on 02/04/2020 17:19:28:

 

Or, I could leave it as. The height difference is about 4", what would happen if I left it like it is?

 

 

It will stop whenever you go upside down, which is not ideal.

That angled plate behind the engine at the bottom of the fuselage, what lives in there? I would be tempted to just chop through that angled plate and stuff the tank in there.

Also what size tank are you trying to use? even 10oz would probably do if space is tight. No need to fit a bucket

109 tank.jpg

Edited By Jon - Laser Engines on 02/04/2020 17:37:48

Thread: Flap / down elevator mix
02/04/2020 16:52:21
Posted by John Lee on 02/04/2020 15:25:36:
Posted by Jon - Laser Engines on 02/04/2020 14:05:35:

As i said before, it depends on the model. In my case i am flying big/heavy WWII fighters vs your example of a light weight foamy.

The 'light weight foamy' in this case (Carbon-Z Cessna 150) is 2.1 meter in span & weighs 10lbs! Not as big as your warbirds maybe but I think still reasonably substantial.

10lbs is really light for a model with that sort of wing area. My Seafury is 14lbs heavier with nearly 3 inches less span! Light weight it is not and with flaps and gear down i need nearly half throttle just to keep it moving.

Simon is also quite right about the c/p moving about.

02/04/2020 14:05:35

As i said before, it depends on the model. In my case i am flying big/heavy WWII fighters vs your example of a light weight foamy.

In real terms the foamy dosent need flaps which is what i was on about before with the pitch up. Again on takeoff the power/weight/drag ratio of a foamy is not the same as 24lbs of warbird with flaps like a barn door!

Thread: First Warbird?
02/04/2020 13:03:29
Posted by Nick Somerville on 02/04/2020 12:20:22:

I have seen quite a few ESM warbirds listed on the YTinternational.co.uk website. Anyone brought from them?

If you are well versed in gliders that will help as rudder control is important on warbirds. The thing that is likely to come as a shock is the weight, drag and sensitivity on the elevator. Very low elevator rates are needed and i can loop my sea fury on probably 3mm of movement.

As for YT, they are no longer trading as ESM shut down. Bigplanes.nl have a few scraps left but once they are gone thats it.

The ESM models fly well but need a little work to tidy them up. If you expect to shake the box and have it build itself thats not going to happen!

I have 6 ESM models in total with 3 flying (la7, P39 and Sea Fury) and 3 (a6m, Fw190, Bf109) waiting their turn. They all fly well and big planes price of about 650 quid for an 80 inch sea fury with retratcts is not a bad price at all.

Thread: Flap / down elevator mix
02/04/2020 12:16:12

dont use flaps for takeoff as they add drag.

Beyond that i would set the radio to the elevator flap mix menu and then fly the model. Once its up put the flaps down and dial in the offset you need while up in the air. If you need it, get someone else to beep the buttons while you fly.

Also be aware that all of the models i fly with elevator flap mix need up trim as the drag of the flaps pulls the nose down. If you are ballooning up with flaps down you are likely to be either too fast, or the model is so light you dont need them really anyway.

Clearly there are always exceptions, but generally thats how it all works out.

Thread: First Warbird?
02/04/2020 11:13:56

Nick do you have any warbird experience already? I only ask as many come a cropper with warbirds as they require a different technique, different setup on the control and generally tend to be rather porky vs a sport model.

I dont know your experience level so apologies if its all under control but in general if you cant nail every landing exactly the same and more or less perfect you are going to have trouble as retracts just wont wear it. If you have not flown a warbird before you might do better to start on a slightly smaller ARTF.

Scott has the scale of the model about right. 80 inches is the 30-50cc sort of bracket and there are plenty of options available but as already discussed its a case of kit vs artf and all the rest of it.

Its a shame the ESM La7 is not still available as i love mine and its a great intro into larger warbirds as it is, as these things go, very forgiving. However, if you push it too far there is a very steep cliff edge and it will gladly fall off it for you. Back to my point on retracts, i have only made 3 truly bad landings with my La7 in 10 years of flying it and the retracts have been out of it...3 times.

In terms of warbirds that fly well the P47 has to be top of the list. Massive wings, a fuselage like a whale to get all the gear in, wide undercarriage and nicely proportioned. The P51 isnt bad either and Spitfires fly really nicely at the larger scales. The Jerry bates Hawker Tempest II is a great model as well and my ESM SeaFury is great but demands respect on landing as it weighs a ton. Hellcats tend to fly well but twist retracts are a pain in the backside. Corsairs are mixed bag.

However, models like the early Spitfire, Hurricane, Fw190a series etc can be problematic with balance as they all have short noses. P51's and late Spitfires have longer noses which helps.

Bigplanes in the nethlands happen to have a sea fury in stock. Price includes retracts which is not bad **LINK** You need a bigger engines though, mine has a laser 360 and that hauls the 24lbs around no problem.

They also have an ESM P47. **LINK** never flown one but my other ESM models fly well. I would stick a 180 in this

There is the seagull P47. Its big at 80 inch, needs a 40-50cc really. I would use a 300 or 360 if i got one **LINK**

and finally there is the Hangar 9 P51 20cc. A 150 4 stroke would do very well and there are two of these at my club flying with laser 155's. **LINK**

We could get into kits as well?

Thread: Focke Wolf Ta 154 Laser
01/04/2020 16:00:28

Spacers eh..

Well to be fair they are spacers technically and they are intended to be used on the 120 head bolts as 40mm bolts are too short, and 45mm bolts are too long. But, fit a 3mm spacer on a 45mm bolt and its all good. We could change the head design, but then the bolts on the 150/155, 300, 180 and 360 would be wrong.

Anyway, many of our customers complained they were unable to get 4mm washers that sat nicely on the mounting lug so i used my already existing spacers. They are little thick as washers go, but as it meant i didnt have to make another part i went for it.

Thread: Old Model for old modeller
01/04/2020 14:57:43

If you still have it then i would certainly give it a refurb. If not, the T240 is a good option but it is big! T180's do come up from time to time but you might do better to look for a decathlon kit as they are very similar looking and perform the well in the air. I know there are plenty of ready to fly decathlon's, not sure about real kits though.

A friend of mine has an old and beaten T180 and its a hoot to fly.

Thread: Vynil letters
01/04/2020 12:42:19

They should be fine but a thin wipe of some sort of fuel proofer around the edges is a good idea as it stops oil getting in under the edge and attacking the glue. Anything with a sharp corner is really vulnerable.

I have used clearcoat, clear fuel proofer, thinned epoxy... it makes little difference what you use, just use something to seal them round the edge.

Thread: Does the size of spinner effect prop performance ?
01/04/2020 10:58:17
Posted by Tim Flyer on 01/04/2020 10:44:06:

Frontal area of an aircraft is important for drag . A large spinner that matches the cowl and blends with the frontal profile will reduce drag and help the plane reach higher speeds and reduce propeller slip. In the trade off between loosing a bit of inner prop area, and reducing drag, reducing drag normally wins especially for higher speed aircraft.

Yep, but clearly it isnt that important as the canadians flew all their Hurricanes like this

31/03/2020 22:59:54

the effect is usually very small but if you like you can test it.

Run the engine with your chosen prop but no spinner and check the revs. Fit the spinner and run again. If it revs faster, and it should, its likely the rpm rise will offset the lost blade area. If the rpm rise is significant, you might get away with fitting the next prop up. Say 16x8 up from 15x8 or whatever. 

But, dont loose sleep over it. Its more of a 'for science' test than anything else.

Edited By Jon - Laser Engines on 31/03/2020 23:00:31

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