StuartC Posted October 10, 2015 Share Posted October 10, 2015 Hi. I have been given a 74 inch span p47. Its never been completed nor flown and Id like to get it in the air eventually. I have no idea of the make of the kit but it looks like an ARTF, and its fairly light for its size. As getting glow fuel here is near impossible I was thinking about Petrol. No having ever had a petrol powered model before Im not sure what size of motor would be needed for this kit ( I think it was for a .60+ glow engine ). I also gather I would need differed fuel tubing and tank etc for petrol. So anyone got some pointers on an approximate petrol engine size to look for and where to get the required fuel resistant tubing? Or anything else I should be aware off ? thanks. Quote Link to comment Share on other sites More sharing options...
Former Member Posted October 11, 2015 Share Posted October 11, 2015 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Former Member Posted October 11, 2015 Share Posted October 11, 2015 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted October 11, 2015 Share Posted October 11, 2015 Like Percy I'm no petrol expert having only owned a couple but first things first I would think a 74" P47 would need more than a 60 glow to haul it around....I would have thought somewhere around a 1.20 glow 4 stroke would be required as a minimum. Which ARTF is it? The manufacturer should suggest a range of engines so I'd go for the biggest in the range (on the basis that you can always throttle back) Now, petrol engines.....I've found them to be about equivalent in power to a glow 4 stroke so a 20cc petrol will match a 1.20 glow 4 stroke. Yes you will need different fuel tube...tygon is the stuff but it's quite expensive & there are lots of copies around which aren't as good...petrol tends to make the tubing go hard so plan to replace it occasionally.. As well as petrol resistant tubing you will need a petrol resistant tank bung. Also because the tubing is less flexible a heavier clunk is a good idea...you can get felt clunks for petrol & these work well as a filter. Petrol engines are much more economical than glow & will use about half the fuel so you could fit a smaller tank. You will need a battery for the ignition unit...check the voltage carefully...some CDI units are happy with up to a 2S Lipo (8.4V) whilst some state a maximum of 6V (4 cell NiMH battery). A cut off switch is a good idea too so you can cut the ignition from the Tx. Oh & final point...petrol stinks so make sure you can isolate the fuel in the tank and/or carb. on the way home or your car will stink for days too..... Good luck.... Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted October 11, 2015 Share Posted October 11, 2015 Posted by StuartC on 10/10/2015 13:40:17: Hi. I have been given a 74 inch span p47. Its never been completed nor flown and Id like to get it in the air eventually. I have no idea of the make of the kit but it looks like an ARTF, and its fairly light for its size. As getting glow fuel here is near impossible I was thinking about Petrol. Where is "here"? Several suppliers will courier fuel in relatively small quantities... Edited By Martin Harris on 11/10/2015 10:08:40 Quote Link to comment Share on other sites More sharing options...
Former Member Posted October 11, 2015 Share Posted October 11, 2015 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted October 11, 2015 Share Posted October 11, 2015 Agree with that Percy.....I use those Micromold "clips" that compress & close off the fuel tube......these have worked well but an RCM&E Top Tip for you....the engine is darn hard to start if you leave them closed.... Quote Link to comment Share on other sites More sharing options...
.. Posted October 11, 2015 Share Posted October 11, 2015 Posted by Percy Verance on 11/10/2015 10:13:08: Steve The stinky car *thing* was what finished me with petrol. The journey home after a session sometimes had me feeling a bit sick. Of course fume free synthetic petrol (Aspen) solves this problem, but the downside is cost. Aspen costs about the same as glow fuel, thus negating any saving made by running a petrol in the first instance...... A valid point Percy but I think the petrol engine would use less fuel than the glow so there would still be a saving. Quote Link to comment Share on other sites More sharing options...
StuartC Posted October 11, 2015 Author Share Posted October 11, 2015 Thanks for the replies, and I will answer some of the questions :- Make of the kit - no idea to be honest, and The person who gave it to me didn't know ether ( he was given it as well ). Weight - It actually weighs about the same as my old 55" span Cambrian spitfire ( 5lb without the engine ). So its fairly light for its size but I recon it will be quite draggy due to its fat face. Where is here - Tip of South West Scotland, About as close as you get before your wet then Irish. Petrol would just be so much easier for me to get when I needed it. Based on whats been mentioned for engine size, looking at :- NGH GT25 Two Stroke Petrol Engine from Just Engines or RCG 26cc Gas engine w/ CD-Ignition from Hobbyking Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted October 11, 2015 Share Posted October 11, 2015 Post a pic or three & see if someone recognises it...if it only weighs 5lb then putting a 25cc engine in it might be overkill. Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted October 11, 2015 Share Posted October 11, 2015 The Goldwing P47 is 70" and has an AUW of around 9lb so is in the same ballpark, that suggests a 1.20 four stroke. I'd imagine a 20-25cc petrol would be a good match for a similar sized model and 30cc not excessive once adequately silenced and turning a big prop. Is that 5lb with or without servos, batteries, tank, retracts etc.? It's easy to add 3 or 4 lb to a 5lb bare airframe. Quote Link to comment Share on other sites More sharing options...
Rich too Posted October 11, 2015 Share Posted October 11, 2015 I have the Hanger 9 P47 65" span, and that takes a 20cc petrol (plus a pound of lead to balance😳 I would think something like a 30cc DLE would be ideal. I disagree on the fumes. I use the plastic clips to close the lines and get no smell in the car at all. Edited By Rich2 on 11/10/2015 15:22:43 Quote Link to comment Share on other sites More sharing options...
StuartC Posted October 11, 2015 Author Share Posted October 11, 2015 ok, heres a pic of it, if anyone can ID the kit from it Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted October 11, 2015 Share Posted October 11, 2015 yep, it's definitely a P47 Is it a glass or wooden fuselage? Quote Link to comment Share on other sites More sharing options...
Former Member Posted October 11, 2015 Share Posted October 11, 2015 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted October 11, 2015 Share Posted October 11, 2015 YT one looks a little different....see here...& has a 71" wingspan...... It says it's ideal for a 26cc petrol motor though. AUW 14-16lbs which is some way off the 5lb Stuart suggests although we don't yet know if that is just the airframe weight.... Quote Link to comment Share on other sites More sharing options...
Alan Gorham_ Posted October 11, 2015 Share Posted October 11, 2015 It looks like the old CMP one that Flair used to distribute. I think a 1.20 four stroke was recommended. Fairly certain it was GRP fuz and built-up wings. Quote Link to comment Share on other sites More sharing options...
StuartC Posted October 11, 2015 Author Share Posted October 11, 2015 Yes its some sort of composite fuse + Built up wings. Quote Link to comment Share on other sites More sharing options...
Jon Laughton Posted October 12, 2015 Share Posted October 12, 2015 Stuart I think you will need something like the 33cc Evolution gas engine recommended for the H9 1/5 scale Spitfire or the more expensive OS alternative: more power will mean less lead in the nose to get the c of g correct which is common in WWII warbirds and the flight performance will be better Alternatively you can resolve your glow fuel supply problem by buying from WestonUk on line - they deliver by post and the service is very reliable / fuel is very good? Jon Quote Link to comment Share on other sites More sharing options...
Braddock, VC Posted October 12, 2015 Share Posted October 12, 2015 Don't know what engine the plane needs but I've had an ngh 25 from HK, it pulls my xtrawot vertically with an 18x8 prop. I also have a turnigy 26 cc from HK which is definitely more powerful but much lighter than the ngh. Of the two, the ngh is an easy fix into the model using standard beam mounts so on that count that's the one I'd go for. The standard as supplied silencers are absolute rubbish and you'll need to spend upwards of £50 to keep the noise acceptable. FWIW the HK wrap around silencer for 26 - 30 does a half job on the turnigy, the ngh is more difficult to cater for due to the narrow exhaust port that also has a 38 mm pitch for the exhaust manifold bolts. I made an adaptor and used an OS 160 Fx silencer which reduces the noise to about 83 dBA, not perfect but that's at full chat. I think the asp 180 2 stroke silencer would do but you'd need to make an adaptor plate. Best of luck with it. Quote Link to comment Share on other sites More sharing options...
StuartC Posted October 12, 2015 Author Share Posted October 12, 2015 Bugger, both the above mentioned engines are on back order. Noise isn't a problem as im in direct competition with the noise of a near by Go Cart racing club and Im about a mile from the nearest house. Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted October 12, 2015 Share Posted October 12, 2015 Looks like a Flair /CMP . They flew OK on a 60 2s or a 90 fs. If you go the petrol route consider first the weight. To get the equivalent power of a glow set up will incur extra weight . The petrol engines are generally made from commercial engine parts that are heavier and then need a ignition system and battery . All this extra weight with lower power output . Dont bother with the sub 20cc engines as they are IMO only any good in a high wing floater type model but just not powerful enough in a warbird and petro power only comes into its own from 30cc up The dle 20 is possibly the best option power and cost wise in the size your looking at but will still be heavier than a glow. Make sure the air frame can take the weight and vibes of a petrol power unit. You I'll need either tygon or nitrile fuel tubing and a purpose made or converted fuel tank (gas bung fitted) . Good luck and let us know what route you take and how you get on. Quote Link to comment Share on other sites More sharing options...
Braddock, VC Posted October 15, 2015 Share Posted October 15, 2015 ED I think you're behind the times. My ngh is under a kilo any the turnigy 26cc is about 800 gm. On a plane that needs nose weight they are a pretty good solution. IMO they also swing much larger props than the equivalent 4 or 2 stroke. Both mine turn 18x8 props at about 8 to 8500 rpms compared with a 16 x. 6 at 9000 ish on my saito 125 and OS 91 fx. The only drawback is the size of effective silencers. Quote Link to comment Share on other sites More sharing options...
Braddock, VC Posted October 15, 2015 Share Posted October 15, 2015 Sorry, made an error working from memory, rpms should be 7500 to 8000, the other figure was for 30 cc rcgf. Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted October 28, 2015 Share Posted October 28, 2015 Posted by Braddock, VC on 15/10/2015 12:08:58: ED I think you're behind the times. My ngh is under a kilo any the turnigy 26cc is about 800 gm. On a plane that needs nose weight they are a pretty good solution. IMO they also swing much larger props than the equivalent 4 or 2 stroke. Both mine turn 18x8 props at about 8 to 8500 rpms compared with a 16 x. 6 at 9000 ish on my saito 125 and OS 91 fx. The only drawback is the size of effective silencers. No problem good discussion is what its all about Petrol power is not as powerful as a glow and engines are generally heavier when all the ign etc is included. Normally aspirated Four strokes will always lag behind in the power stakes when compared to a same capacity two stroke, as your comparison of the Saito and 91 FX confirm . I agree that if you need the nose weight then petrol engines are fine if they have enough power for the model type .They are improving petrol engine design all the time mainly by reducing weight with lighter castings and purpose made internals instead of using industrial engine parts. As you say the exhaust is also a big issue , they run much hotter than their 2 stroke glow versions and can damage singe or burn air frames if exhaust gets too close and they have to have a bigger volume to be effective. Taking all that into consideration , am I really behind the times? I still believe that petrol engines only come into their own from 30cc and above . Quote Link to comment Share on other sites More sharing options...
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