Jon H Posted September 25, 2022 Share Posted September 25, 2022 Shame about the arrival at the end but wobbly servos wont help. Could the pitch up be caused by the throttle servo putting pressure on the elevator? Anyway the backfiring at high power is symptomatic of one cylinder going a smidge lean. When this has happened to one of mine its always been debris in the needle but it could be other things like the rear pot getting warm with the cowl off and no ducting. On props, given the performance expected from a Hurricane even a 20x8 apc might be an option. 6800rpm should be more than enough and i was impressed with the power available on the 18x8 Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted September 26, 2022 Author Share Posted September 26, 2022 (edited) As the elevators and rudder are on a pull/ pull system I don’t think that the application of throttle would cause the pitching up as both wires would have gone slack. My feeling is that increasing the throttle caused a lack of movement of those controls as could be seen on the landing in the vid. But I can only guess at this! I think that I need to get it up in the air again to see how it performs with the servos fixed in position, I don’t want to be making any changes until after that flight. I will add a switchable mix, throttle/ elevator, just in case it still pitches up but I’m interested to know if the backfiring problem is still there. As a precaution, and based on your comments, I’ll check both carbs for any grunge before the next flight too. Regarding the power, whilst I didn’t try it, in its present configuration it felt like it would have excellent vertical performance! Edited September 26, 2022 by Ron Gray Quote Link to comment Share on other sites More sharing options...
Jon H Posted September 26, 2022 Share Posted September 26, 2022 I forgot most ESM models are pull pull. I suppose any down trim you might have had would have been lost if the wires went slack? Still, i agree that changes should be minimal until tested again with the servo tray issue sorted out. Was the engine damaged in the nose over? Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted September 26, 2022 Author Share Posted September 26, 2022 All rear end trim was lost, in the end I was flying with full down on the elevator stick, which was interesting! No damage to the engine, in fact the damage was minimal: Prop, not broken but slightly tipped and a few notches (it's now in the bin) Spinner, a few scratches. Fuse, can't see any signs of impact but would I see them given the rubbed down / weathered look it sports? Wing, ditto. U/C, bore the brunt of the landing resulting in bent axles and bent stub oleos (the bit that slides inside the main legs). U/C, oleo retaining screw sheared (the little screw that retains the stub in the legs) Servo tray, broken loose. All of the above have now been fixed with the exception of the oleo retaining screw which I need to drill out. I've got some small Carbide drill bits coming today in case it proves to be a bit difficult. It's not the end of the world as I have identical oleos sitting in my U/C spares drawer! Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted September 26, 2022 Author Share Posted September 26, 2022 (edited) 11 hours ago, Jon - Laser Engines said: On props, given the performance expected from a Hurricane even a 20x8 apc might be an option. 6800rpm should be more than enough and i was impressed with the power available on the 18x8 Just looked at my prop collection and whilst I don't have any APCs in those sizes I do have Xoar and Menz wooden ones in both 19x8 and 20x6. Edited September 26, 2022 by Ron Gray Quote Link to comment Share on other sites More sharing options...
Jon H Posted September 26, 2022 Share Posted September 26, 2022 menz 19x8 might be worth a try. Its a slower prop than the APC but you might see 6800-7000, this would likely be fine for something as relatively sedate as a Hurricane. Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted September 26, 2022 Author Share Posted September 26, 2022 Saves me £30 as well! Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted September 27, 2022 Author Share Posted September 27, 2022 Thought I'd better put the pilot back in as it might help with the next flight 3 1 Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted September 27, 2022 Share Posted September 27, 2022 Nice looking pilot figure. Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted September 28, 2022 Author Share Posted September 28, 2022 (edited) Thought I'd just check the engine running before taking it up to the field tomorrow. The rear pot was running a tad lean on the high needle so turned that out a bit and running fine on WOT, 8200 RPM on the APC 18x8. Tried the 19x8 Menz and it didn't like it all, fluffing and rough running at anywhere above ½ throttle so I didn't bother re-tuning as I'm more than happy with the APC for tomorrow. Edited September 28, 2022 by Ron Gray Auto speeling incorrect 1 Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted October 11, 2022 Author Share Posted October 11, 2022 Having fixed the servo tray I decided to change the tailwheel pushrod arrangement as it wasn’t preventing the tailwheel from moving around quite a bit. So a thicker gauge wire plus spring buffers was installed which made it a lot stiffer but still with shock absorbing. So to the next flight. I changed the prop to an APC 18x8W and decided to fly with the damaged canopy (I didn’t have time to fit the new one). Unfortunately the canopy came off mid flight which forced me to land and this is the video. Having checked everything over I did take it out for another flight later in the day and can confirm that the climbing under power plus the backfiring have now disappeared so it must have been the servo tray coming loose that caused those problems. I need to setup a landing mode on the Tx as I need more elevator authority to flare. I also need to re-tune the engine as it is really messy with lots of oil from both the exhausts and the oil breather, it’s nowhere near as clean as my 2 other in-line twin Lasers! 1 Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted October 12, 2022 Share Posted October 12, 2022 Nice flight Ron, maybe you could do a 'still' of the canopy floating down to earth and de a 'spot the canopy' competition and Jon could offer a free engine as a prize.😆 Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted October 12, 2022 Author Share Posted October 12, 2022 Thanks Paul, it may be in several pieces! Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted November 11, 2022 Author Share Posted November 11, 2022 Following on from the canopy incident I decided that I would try a different approach with adding the framework to the new one. I set to work designing and 3D printing the framework which not only looks better than the aluminium tape (imo) it has given it a bit more strength too! I really must set some time aside to re-do the cockpit details as they are more than a bit 'wrong'. I have been pondering over the tropical filter for the underside of the cowl in order to hide the front cylinder of the Laser 200 in-line twin and this has caused a lot of head scratching as its position and size won't be too scale like (but does that really matter on as ESM Hurricane????) plus making sure that both pots get their cooling from it is also giving me a headache. As a result I hadn't got on with the in cowl ducting but I decided to crack on with that as I've engineered a Naca duct for the rear pot which will allow me to fly the beast with the cowl fitted whilst I still deliberate over a Vokes filter. The internal baffles are glassed ply. The keen eyed amongst you will also note that I've changed the silencers back to the standard 'long' type rather than the 'short pot' ones, which means that the exhausts are pointing down rather than to the side. What is not shown in this photo are the 2 temp sensors I've fitted to monitor the temperature differential between the 2 cylinders whilst it's flying. 1 Quote Link to comment Share on other sites More sharing options...
leccyflyer Posted November 11, 2022 Share Posted November 11, 2022 Canopy looks fantastic Ron - any chance you might make the stl file available? Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted November 12, 2022 Author Share Posted November 12, 2022 I took the Hurri up to the patch today and retuned the engine as it was running too rich resulting in a very messy airframe. Having done that I then fitted the naca duct equipped cowl and took off, completing an 8 minute flight flown at very near to or full throttle for most of it. Checking my telemetry shows that the rear cylinder head recorded a max temp of 90°C (bearing in mind that the sensors are not actually touching the head this is a bit on the low side) which was only approximately 5° higher than the front one. My conclusion is that the naca duct plus cowl baffles are working! It also sounded better (imo) with the standard silencers in place. 4 Quote Link to comment Share on other sites More sharing options...
Philip Lewis 3 Posted November 12, 2022 Share Posted November 12, 2022 That canopy is not modelling it's artistry Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted November 12, 2022 Author Share Posted November 12, 2022 (edited) I know that I said that with the 3D printed frame parts it now appears a lot stronger, well today I got chance to prove it! After a nice touch down I was coming to the end of the tail up part when a wheel got caught in something which made it flip nose over onto the canopy and fin. The canopy survived that little mishap! Edited November 12, 2022 by Ron Gray Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted November 12, 2022 Author Share Posted November 12, 2022 On 11/11/2022 at 18:19, leccyflyer said: Canopy looks fantastic Ron - any chance you might make the stl file available? No problem but the parts will only fit the canopy for this model! 1 Quote Link to comment Share on other sites More sharing options...
leccyflyer Posted November 12, 2022 Share Posted November 12, 2022 Aaah, mine's the smaller 71" span version of the Hurricane. Quote Link to comment Share on other sites More sharing options...
Gary Clark 1 Posted November 13, 2022 Share Posted November 13, 2022 (edited) You can scale them in any slicing software so if the shape is the same (should be) then just change the size before it's printed. I do the same with exhaust stacks and cowls I've made Gary Edited November 13, 2022 by Gary Clark 1 Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted November 13, 2022 Author Share Posted November 13, 2022 Normally I would say yes but in this case the canopy is for an 88” span Hurri which I’ve then cut down for the 82” one so the scale geometry is not quite right! The best thing would be to measure the canopy sides against my design then scale the sides, ditto the front ¼ panels, the windshield and the top frames. 1 Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted November 13, 2022 Author Share Posted November 13, 2022 (edited) Whilst not perfect scale I think these zorst stacks look quite good (not of my making, apart from the paint!) Edited November 13, 2022 by Ron Gray 5 Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted November 17, 2022 Author Share Posted November 17, 2022 I flew the Hurri on Monday but when I came to pack up there was a lot of oily mess in the underside of the fuselage and I’d only flown three 8 minute flights, which, for a Laser running the low oil fuel, was most unusual. The only problem is that due to the breather out let being quite close to the exhaust I couldn’t really tell where the oil was coming from. The fuel mixture has been leaned off so I called Jon at Laser and he suggested to either blank off the breather or fit a catch tank for the next flight so that I could see where the oil was coming from. I decided on the catch tank option and was able to fit a 2oz fuel tank behind the engine with a hole in one side for the breather nipple, the whole thing being trapped against the bulkhead when I tighten the motor mount. You can just see the breather nipple inside the tank Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted November 17, 2022 Share Posted November 17, 2022 I can't see the oil or the rounded off ends of the brass tubing . Quote Link to comment Share on other sites More sharing options...
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