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Snorbitz

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Posts posted by Snorbitz

    Seagull Challenger Sport LW C of G

    in Sport, Aerobatic and 3D kits

    Posted

    Hi oh gurus of the sky,

    So I've popped together a Seagull Challenger Sport LW to replace my now broken XT40. C of G is quoted as 60mm back from the LE. I've built to plan and got my 6v battery as far forward in the cabin as it'll go. It's actually in the removable hatch immediately behind the bulkhead and without a ton of lead in the snout I can't get the balance any further forward that about 80mm. SC52 up the front should be heavy enough I would have thought. Your thoughts would be appreciated please gentleman. 🙂

    SC52 2stroke issue.

    in IC Engines

    Posted

    Hi Caveman, I'm glad it's not just me that realized the tank install isn't correct. The way it's fitted now also does not allow for insulation. I like to encase my tanks in foam to stop foaming. I'm pretty sure the needle valve rubbing on the cowl made it spin round. It didn't happen in a whole day of running without the cowl which makes it the only difference. So I'm going to open the hole out around the valve to allow enough space for me to get some silicone hose over it. I checked the tang as you'd mentioned and it looks ok. I think just opening the hole out would do the job alone (I've never had the issue on this engine before in previous planes) but my heart can't stand another dead stick so I'm going belt and braces. It could just be that the vibrations on this model can do what has never happened on previous models. Typically in all the modelling stuff I have I don't have a peice of hose with the correct ID so a visit to town today should sort this out. Then it's flight No2.

    SC52 2stroke issue.

    in IC Engines

    Posted

    Hi Alex, the carb is on backwards I know and this was also another change I had to make to get the whole thing installed. However if you think about it even the other way around the needle will still be in the centre of the venturi and the throttle flap/roller thingy simply increases or decreases the air flow into the combustion chamber so I'm not sure this would change much. On the orientation if I fit the engine the other way up and then fly inverted which let's be honest this kind of model should do a lot of isn't that the same thing. As somebody said earlier the engine should be capable of running in any orientation and I tend to agree. Now I've got the running sorted I just need to stop the needle valve turning round in flight (I'm going to open the hole in the bodywork out and put some silicone tuube over it) I thinks it's jobs-a-goodun. One change I will be making though is on the fuel tank itself which currently is angled up towards the engine by about 15degs. It's how the instructions show it but I prefer a horizontal tank so it does not run out earlier when flying inverted. I'll take a picture of that so you can see what I mean. I had to add 15g of lead to the tail for COG so shuffling the tank back a bit might eleviate the need for the lead or so much of it anyway.

    Edited By Snorbitz on 01/01/2019 18:37:54

    Edited By Snorbitz on 01/01/2019 18:41:53

    SC52 2stroke issue.

    in IC Engines

    Posted

    Hi Martin...yes the fuel pipe run is not ideal but the "P" clip is there to prevent the fuel pipe touching the back plate of the spinner...its all very tight in there. The blob of orange is a fuel proof silicone to stop the pipe sliding forward through the clip with does not clamp but merely guide the pipe. During the extensive engine running i did to set the thing up no bubbles/frothing could be seen so at this stage i'm ok with the way it is.

    Mr Hargreaves, You are correct the needle is a pain to get at and considering the proximity to the prop a burn would be preferable....lol. I'm not one for needle fiddling too often once its set up so yes it did take many stop/starts but i got there in the end. The fact that i could effectively flood the engine to stopping point (while the needle was too far out) tells me there's enough fuel flow i think.

    SC52 2stroke issue.

    in IC Engines

    Posted

    Ok..first of all Happy New Year to everyone. I have a semi-happy conclusion to share with you all. Someone mentioned about running the engine upside down..that would prove/disprove if the inverted installation was the issue. This started me thinking...so just to recap the engine originally started and ran fine then would cut out at WOT...it would then not restart. On my older Pulse XT40 after flying i remembered i always picked up my model in such a way that the oil residue in the exhaust would drain out onto the floor while it was still hot as i walked back from the flight line. It always started like a dream. So if this residue was now draining back into the combustion chamber because of the orientation there's no way the humble glow plug could burn this all off and fire. Turning the plane upside down did indeed make it start everytime...however it was running incredibly rich and still struggled at WOT.....as you can see in the photos the proximity of the needle screw is too close for easy adjustment while running so after a 2 tanks of fuel and many stop/starts i got the mixture screw in from 2.5 turns out to only 3/4 of a turn out and it was running just sweet. Time to turn the plane back the right way up. It also ran the just great even at WOT and this is still on the old fuel (new stuff wasn't delivered on Monday) . I checked the bearings as suggested and all good there with no rust or free play. So i decided that i could live live with the quirk and after flying in future i'd store it upside down for a short while to drain the residue out. No great drama.

    So this morning i refitted the engine cowl and decided the weather was maiden friendly. I mowed my strip to within an inch of its life in the paddock and set up my restraints. Went through the last minute checks and paranoid checks again and again and took her out to the flight line. All good so far. Its been a while sine i've flown (Radian Pro aside) so i was understandably a tadge nervous. Did a few practice runs down the strip....she ran nice and true so all good......headed her into the wind and went for it. Climb out ok gained some height and got round 2 gentle circuits. Running level on about 1/3 throttle so no great changes to struggle with this time i thought and i was just starting to relax when the engine note faded and i was dead stick on a maiden with an unfamiliar plane not knowing how far it will be able to glide. I had in my mind that i had read somewhere these Extras don't do gliding very well...this is true!!!...it took a split second to realize it was never going to make it back to the strip so i opted for a long grass field next to ours. It came in quite heavy on the wheels and bent the undercarriage a bit but somehow its otherwise intact.

    Inquiry time...Remember i said that the needle screw was only 3/4 out . Well i'd marked it with a paint pen when i was fiddling with it and had refitted it 3/4 out so i knew exactly where the paint mark should be. It had wound itself right in!!!!. How...well i think it was just rubbing on the cowl which of course wasn't there all through the engine running yesterday. Plan is to open the hole out where it sticks through the cowl and put a length of silicon pipe (unless there is a better solution) tightly over the top to stop it turning once set again and try again. Phew i consider myself very lucky. So all that remains is to say a big thank you to you all for your input. It was much appreciated. I'm sorry if you don't like the look of the exhaust sticking out the top but in this case i'll live with it.

    SC52 2stroke issue.

    in IC Engines

    Posted

    I've removed the cowel now and refitted everything up so I'll take some pics for your analysis and try running it upside down...I've also ordered some fresh fuel. That should be with me on Monday. I looked into the exhaust extension but even JE didn't have one as long as I needed.

    SC52 2stroke issue.

    in IC Engines

    Posted

    Trust me it wasn't through choice....it would've taken some major reconstruction of the firewall to get it to fit even without the extra peice in the silencer. The glow plug access is on the right. If I have to remove the cowel which I'm a little loathed to do now I'll take a picture of it too just so you can see what I've done.

    SC52 2stroke issue.

    in IC Engines

    Posted

    I'm using a separate battery for the starter so it shouldn't drag the voltage down under load. I've had a coffee and a read so time to try again with some of these suggestions and with the new glo driver.

    SC52 2stroke issue.

    in IC Engines

    Posted

    Lots to work through. I'm going to try another Glo system too as the plug does not glow overly well when out even though the little needle swings right over. On my glow panel which I'm about to try how much current should I dial up for a No3 plug?

    SC52 2stroke issue.

    in IC Engines

    Posted

    Hi Guys, I've just refitted an SC52 2stroke after a 3 year layup and its also has a brand new carb from JE. Old one was missing a part. Started just fine, idled perfect and mid range ok but it will not run at WOT. Just cuts out....this happened a few times and now it won't run at all. It's a new model with the plumbing checked and double checked. Scratching my head a bit. I've gone to 2,5 out on the needle, tried a new plug but still nothing. Very odd.Any ideas?.

    Exhaust options

    in IC Engines

    Posted


    Hi guys
    I've got a bit of an exhaust dilemma. My SC52 only fits at 90degs to the vertical (lying on its side) in its new home so a standard muffler would require cutting into the firewall....not my first option of course. Is there an exhaust option to deal with such an installation?

    Edited By Snorbitz on 09/10/2018 10:14:26

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