Ron Gray Posted September 6, 2018 Share Posted September 6, 2018 A truly great day up at the field today. The GA30 started first time but it was clear from the first flight that it was running too rich. So after an 8 minute flight I landed and adjusted the low needle by 1/2 turn to lean it out. subsequent flights were all mad eon this setting but I will be revisiting it as it's still not quite right. Having said that it performed brilliantly hauling the Giant Sportster (7.5Kg) around without an issue. A friend took the following videos which show snatches from various flights. In all I flew 7 flights of about 10 minutes each (apart from the first one mentioned above). I change dates prop back to the 18x8W APC and it seemed happier with that one so the next step will be to run it on a 19x6. Unedited vids here: I will be replacing the alloy engine mount with a glass filled nylon one as I think that will make it quieter. Quote Link to comment Share on other sites More sharing options...
Jon H Posted September 27, 2018 Author Share Posted September 27, 2018 Just a small update I received word back from our test pilot Bob who has a GA25 (155) fitted to his 82'' 14lb DH Chipmunk. He reports all is well with scale flight at around 1/3-1/2 throttle when using a 17x8 propeller. Power is significantly increased vs the 20cc petrol 4 stroke that powered it previously. Club members have apparently all commented on the low noise of the engine and the video he shot me of the model flying in one of our recent gales certainly shows this well. There is a fair bit of wind noise on the mic, but vs the two strokes in circuit with him, it seems very quiet to me. Now all i have to do is build more. Quote Link to comment Share on other sites More sharing options...
Tim Flyer Posted September 27, 2018 Share Posted September 27, 2018 Very nice . Really shows how much better the 4s sounds than the strimmer like 2s. I’m not surprised he has lots of power to spare as in my view your 100 4s is close to an “ordinary “ e.g DLE petrol 2s so the 155 4s is way stronger than a standard 4s 20cc petrol like an NGH. Quote Link to comment Share on other sites More sharing options...
Former Member Posted September 27, 2018 Share Posted September 27, 2018 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted October 4, 2018 Share Posted October 4, 2018 At the risk of boring the pants of thread viewers, the latest update on my testing of the GA30. Still using the GP Giant Sportster as the test bed. I changed the prop to a standard APC 18x8 ( I had been running it on an 18x8W) plus I leaned the engine by 1/8th on the low needle, results were immediately apparent as the engine ran a lot (cleaner, no hiccups) better giving me far better performance all round, in fact I was able to carry out the full Clubman F3a routine with no problems (well, apart from the pilot!). In all I had 1 hour of flight time, each stint lasting 12 - 15 mins and the engine never missed a beat, I should also add that all starting was done by hand, no leccy involved and with the new choke plate installed cold starting was straightforward. Next up is to replace the 180 glow in the Hurricane with a GA30 to see what that is like. Whilst flying yesterday a colleague commented “when you’ve finished with that Norton engine, I’ll have it”. Plus I wasn’t allowed to kill the engine for several minutes after landing as fellows fliers just wanted to listen to it on tickover! I certainly haven’t had those comments / requests when flying one of my leccy ‘planes (hope BEB doesn’t read this!) Quote Link to comment Share on other sites More sharing options...
Jon H Posted October 4, 2018 Author Share Posted October 4, 2018 Nice one Ron Things are moving (very slowly) along over here as well. 4 more GA30's ready for sending to their respective owners. Quote Link to comment Share on other sites More sharing options...
Nigel R Posted October 4, 2018 Share Posted October 4, 2018 "Air bubbles are the engines arch nemesis and clearing the fuel system of air before starting is very important." Probably a daft question at this stage - is there an easy procedure for ensuring the fuel system is primed and free of air bubbles? Even more daft question from idjit who hasn't read the whole thread - are you using any kind of bubble trap, or does the carb have a float chamber to take care of that kind of thing? Quote Link to comment Share on other sites More sharing options...
Jon H Posted October 4, 2018 Author Share Posted October 4, 2018 Posted by Nigel R on 04/10/2018 09:51:16: "Air bubbles are the engines arch nemesis and clearing the fuel system of air before starting is very important." Probably a daft question at this stage - is there an easy procedure for ensuring the fuel system is primed and free of air bubbles? Even more daft question from idjit who hasn't read the whole thread - are you using any kind of bubble trap, or does the carb have a float chamber to take care of that kind of thing? There are two separate bubble related issues to contend with. 1. Clearing the fuel system of air before starting the engine 2. Making sure the fuel supply does not allow air into the system once the engine is running. Issue 2 is covered off by the choice of tank, assembly of the tank and clunk, and the choice of clunk. All of this is detailed in the instructions and there is an A4 size diagram showing how to do it. Essentially you want a larger tank than is needed for your intended flight duration and you put the felt clunk in the middle. This guarantee's the clunk is always immersed as plenty of fuel remains even at the end of the flight. You could try using header tanks and all the rest of it but that adds more complication so i just went with the simple option. I also have not tested that setup yet so dont want to recommend it. Issue 1 is the one that caused Ron the most trouble as he did not have the intended choke on his engine when he first got it. With the choke now fitted and his priming technique perfected i believe its now full steam ahead. Originally i never had a choke on the engine and purging the pump of bubbles was a problem so i fitted a primer bulb to draw the fuel through. This was ok but not perfect. Once i finally fitted the choke i found that the primer bulb was no longer required so dropped it. If you wanted, you could fit one but its another pair of T pieces and a bunch more connections that need to be checked for leaks. Again, there is a procedure in the instructions that detail how to get the engine going. As with any new product there are going to be some issues but i suspect most will be down to user error. I dont mean that negatively, i just mean that the engine is different to what most people are used to. It will take a little while for people to understand how exactly to get the best out of the engine and once they do it will be a walk in the park as its really simple once you know how. Clearly through this early phase feedback from customers is vital so that we can update the instructions and minimise misunderstanding. Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted October 4, 2018 Share Posted October 4, 2018 Just to add to what Jon has said. Initially I had major problems with my GA30 but not fully understanding that it was an air bubble problem I spent ages adjusting both the high and low needle settings - BIG mistake! After carrying out all of those adjustments I went back to the fueling side of things and had several conversations with Jon about it. In the end, as detailed above, I attached the fuel bottle hand crank fuelling pump to the output from the engine’s pump and sucked the fuel through. This in turn sucked out the air that was trapped in the pump and allowed me to get the engine running after putting both needles back to factory settings. As Jon says, if the choke plate had been on my engine to start with I don’t think that I would have had the same issues as now all I do is close the choke plate, flick the prop over 4 or 5 times, open the choke, 2 flicks and it runs. I suspect that if I used the leccy starter it would be an even quicker start! The main point that I’m trying to make is that I should not have altered the needle settings, I should have thought more about the root cause of the problem and resolved that first. With this knowledge I can now look forward to running more of both the GA30 and 20s when they become available, because I for one will be in the queue for some more! Quote Link to comment Share on other sites More sharing options...
Nigel R Posted October 4, 2018 Share Posted October 4, 2018 Thanks gents. Sounds like you have it covered Jon Simplicity is often best. Quote Link to comment Share on other sites More sharing options...
Jon H Posted October 4, 2018 Author Share Posted October 4, 2018 To be fair to Ron i did stitch him up not having the choke ready when i sent the engine. He was just so keen! The other thing that tripped him up was the needles are very sensitive and without the engine running its hard to judge their effect. In this instance the engine seemed lean, so glow engine autopilot kicked in and a half turn here and there is cranked on the needles. This is great, and i would have probably done the same if i didnt know the engine, but petrol engines are tuned in 1/16th's so a half turn takes it miles outside its operating range and then it wont work even if the pump had been clear of air. The instructions note that the needles are very sensitive and recommend no more than 1/8 turn movements. Ron knew this, but in the heat of the moment its really hard to 'forget' many years of modelling experience and remember that one line from the instruction sheet you skimmed through in the 30 seconds before excitement got the better of you and you ran off to play with your new toy. I am not being critical, just trying to point out how easy it will be to get it wrong through nothing more than a split second of autopilot. This is why i am looking for as much feedback as possible so that we can make the instructions as comprehensive as we can. All i ask after that is that people read them and make reference to them instead if assuming they know what to do in the event of a problem. Some may read this and think 'cor that engine sounds like a pain in the backside' but that is not the case. It just needs to be treated a certain way and once you understand that its essentially a flick and forget engine. I just want to warn people to forget everything they think they know, at least for the first few runs, and trust the advice they will have been given when buying the engine and what is written in the instructions. Quote Link to comment Share on other sites More sharing options...
Nigel R Posted October 4, 2018 Share Posted October 4, 2018 Big 30pt text disclaimer - "not a walbro carb" "not a glow engine" Is the needle sensitivity common to many petrols? Just thinking that there will be owners who have come straight from other petrols, and will assume their experience applies - or to put it bluntly, RTFM they will not! Quote Link to comment Share on other sites More sharing options...
Tim Flyer Posted October 4, 2018 Share Posted October 4, 2018 One question I have on the petrol engine although it might sound frivolous to some is can you entice it to “pop” like the other Large Lasers. I do love getting a “pop” out of the 155 by opening the throttle on a dive and then rapidly closing it causing fuel to be drawn in on the over run which is then ignited in the exhaust with a rather satisfying pop. That certainly suits the Wots Wot Xl easy flying style. Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted October 4, 2018 Share Posted October 4, 2018 I have quite a few other gas engines, all with Walbro carbs, the Laser requires a different approach, it is a new experience! Quote Link to comment Share on other sites More sharing options...
Manish Chandrayan Posted October 4, 2018 Share Posted October 4, 2018 Posted by Jon - Laser Engines on 04/10/2018 09:44:42: Nice one Ron Things are moving (very slowly) along over here as well. 4 more GA30's ready for sending to their respective owners. When can I order one ? Quote Link to comment Share on other sites More sharing options...
Jon H Posted October 4, 2018 Author Share Posted October 4, 2018 Nigel, you have hit what i think will be the biggest issue. People will assume they know how it works and they will be wrong. As Ron mentions, its a new experience but its not exactly difficult. Tim, not really. As the fuel metering is better with the petrol they are very much less likely to pop and crackle. Its my only real regret Manish, same as always. When they are ready! Quote Link to comment Share on other sites More sharing options...
Manish Chandrayan Posted October 4, 2018 Share Posted October 4, 2018 Jon I see four ready in the picture. When can I put my name for one? Quote Link to comment Share on other sites More sharing options...
Jon H Posted October 4, 2018 Author Share Posted October 4, 2018 Posted by Manish Chandrayan on 04/10/2018 14:41:43: Jon I see four ready in the picture. When can I put my name for one? They are pre production and already have homes. As discussed at length i need feedback from customers to mak sure i have it sorted. Once production engines are ready i will gladly take your order. Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted December 5, 2018 Share Posted December 5, 2018 A bit of an update. My GA3O powered ESM Hurricane met with an untimely end without me really testing the engine but I was lucky enough to locate another one, unflown. So having installed the GA30 into its new home and having added the thick end of 2lb of lead to the nose, the 20lb ish Harry Mk2 was ready to fly. Yesterday was ideal so no excuses and took it with me to the field, ran up the engine using an 18x8W APC prop but felt that it wasn’t giving its best which was born out with me snorting 2 takeoffs. Fortunately I also had a Menz 18x6 prop with me so fitted that and gained another 500 rpm. That made all the difference and it took to the air without any issues. A few full throttle circuits later I slowed it down to about ¾ throttle for some real scale like passes and swooping flowing banked turns. This was followed by some ¼ throttle slow passes with full throttle pull ups at the end of the pass. I completed several 7 - 8 minute flights and was happy to note that the GA had been sipping at the fuel tank, an added bonus. The engine has passed its ‘scale’ test easily hauling a 20lb ‘plane through the air with some to spare. The next test will be with different size / make props to see if this can be improved upon. I had a big smile on my face driving home from the field and can now concentrate on adding more scale to the airframe. Edited By Ron Gray on 05/12/2018 17:57:30 Quote Link to comment Share on other sites More sharing options...
Jon H Posted December 5, 2018 Author Share Posted December 5, 2018 Nice one Ron If i ever get round to building it i will be fitting a GA30 to my DB MkI Spitfire. I intend to do it as a cannon equipped MKIa and already have the paint job picked out. Given its sat in the corner of the room for.....oh dear, about 10 years in its half built state, i doubt its going to be ready any time soon! As for fuel consumption i was surprised to find my Stampe has a 14oz tank not 16 like i thought. Given that i have had flight times easily over 20 minutes with a good 50% fuel remaining at the end fuel consumption is very low. One thing i have noticed is that my GA25 prototype uses more fuel than the GA30. The other GA25 which is out with a customer is reported to be extremely frugal and uses half the fuel mine does. I suspect this is down to the RPM the engine is running at as the GA25 in my model is doing high revs on the smallest prop the engine uses. The other is revving slower on a higher load prop. It seems that fuel consumption is more closely related to RPM than it is to load which is more or less the opposite of a glow engine. Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted December 5, 2018 Share Posted December 5, 2018 A Mk 1A with cannons??? Quote Link to comment Share on other sites More sharing options...
Jon H Posted December 5, 2018 Author Share Posted December 5, 2018 Posted by Martin McIntosh on 05/12/2018 20:17:43: A Mk 1A with cannons??? Ib, my mistake. Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted December 5, 2018 Share Posted December 5, 2018 Oops just got home and noticed a couple of typos in my earlier post. For snorting read aborting and Menz 18x6 should have been 19x6. I blame it on typing the post on my iPhone whilst sat in Edinburgh airport waiting for my flight home! Quote Link to comment Share on other sites More sharing options...
Tim Flyer Posted December 6, 2018 Share Posted December 6, 2018 I thought that was strange Ron 😉. My 180 Glow in my Hurricane goes best on an 18x10 . The make I have is a “just engines” wooden 18x10 which was quite mild in pitch for a 10 , but runs well. . Anyway great to hear u managed to fly despite poor weather recently. Our runway is far too soggy now . No Warbirds there until spring I think... Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted December 6, 2018 Share Posted December 6, 2018 Thanks Tim. Fortunately we have a tarmac runway so mud isn’t a problem but I did land it on the grass each time as it looked far better! Quote Link to comment Share on other sites More sharing options...
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