gowen Posted July 18, 2022 Share Posted July 18, 2022 This is my first time posting here, so apologies if I'm treading old ground. I did a search and the only thread that comes close is "Techpower 5 v Optimax". Since restarting the hobby, I have only flown electric. I recently came into possession of a Cox .049 Queen Bee and I though I'd put it in a vintage style airframe. Researching the fuel requirements for this engine, It seems I need 20% to 30% nitro, and 20% lubricant of which, at least 10% must be castor (https://www.mh-aerotools.de/airfoils/documents/cox_049_operation_and_troubleshooting_guide.pdf) Model Technics GN-25 or GX-25 would have been ideal, but is no longer available and I can't find direct alternative. I contacted Den's model supplies, as a seller of Cox engines and he recommended buying Big Bang 25% and adding 10% castor oil. The problem is that Model Technics Castorlube is out of stock everywhere is all can sizes. So the question (finally), Does anyone: 1. Know where I can buy some castorlube. 2. Suggest and alternative brand of castor oil. 3. Suggest an alternative fuel that is available. Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted July 18, 2022 Share Posted July 18, 2022 My cox engines run with 10% nitro, I do add some castor to the fuel that I buy bringing up the oil content to at least 20% Quote Link to comment Share on other sites More sharing options...
Don Fry Posted July 18, 2022 Share Posted July 18, 2022 Gowen, welcome. My opinion, caster oil smells nice, will clear yer pipes right quick if you haven’t been eating enough fiber, and makes a nice tahini. But it’s ancient technology, and has been replaced by modern synthetic oils, and has no place in a fuel. I would use a 20 to 30 % nitro methane fuel, and whatever synthetic oil it comes with, but to be cautious, I think I would want 15% plus in there. The Big Bang is good to go as it is. Quote Link to comment Share on other sites More sharing options...
Flying Squirrel Posted July 18, 2022 Share Posted July 18, 2022 It may be worth contacting Model Shop Leeds, always very helpful and good stocks of fuel. You may already know that Model Technics are out of business but Optifuel have taken over the brand, which MSL sell. https://www.modelshopleeds.co.uk/catalog/index.php?cPath=291_646&sort=1a&action=view_product&products_id=79620 Quote Link to comment Share on other sites More sharing options...
J D 8 Posted July 18, 2022 Share Posted July 18, 2022 My Cox TD 051 runs very well [ scary well ] on 15% Model Technics " copta fuel" As above contact MSL for similar. Engine is in a Midget Mustang C/L racer. 1 Quote Link to comment Share on other sites More sharing options...
Andy Stephenson Posted July 18, 2022 Share Posted July 18, 2022 The fuel of choice for Cox engines back in the day was Nitrex 15. They seemed quite happy on this mixture, I'm not sure about the lubricant, it had 15% nitro which seemed enough. Fuel with 30% nitro needs an explosives licence in the UK and they are thinking of lowering it to 16%. I met a guy in the states who was using 45% nitro in his but this was excessive and unnecessary. 1 Quote Link to comment Share on other sites More sharing options...
gowen Posted July 18, 2022 Author Share Posted July 18, 2022 Thanks for all your replies. In all my searching, I never came across Optifuel Benol Racing Castor Oil. Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted July 18, 2022 Share Posted July 18, 2022 Yamada Mix (Model Technics) is 20% nitro plus 23% Klotz synthetic but do not know if Optimax will continue it. Southern do a 20% nitro plus 20% synthetic but a gallon of either would last several lifetimes in a Cox. As has been said above, 15% nitro is plenty, other than on the Cox 010. Must fly my Queen Bee sometime. It is in a Mini Blitz. Quote Link to comment Share on other sites More sharing options...
Brian Cooper Posted July 18, 2022 Share Posted July 18, 2022 Back in the 1960s, when Cox .049 engines were everywhere, we used Nitrex 15. This had 15% nitro, and the little engines happily screamed into life with their instantly recognisable, high-pitched note. From recollection, they were quite fussy about fuel. They didn't run well on anything less than 15% nitro. Quote Link to comment Share on other sites More sharing options...
brokenenglish Posted July 19, 2022 Share Posted July 19, 2022 (edited) Just found this. IMO, there's some confusion in the OP. A Cox Queen Bee is an .074, not an .049, so which are we discussing? Is your engine a Queen Bee or is it an .049? Whichever engine it is, and in spite of the dogmatic remarks made above, IMO, you'll need some castor in the fuel. IIRC, KK Nitrex (in the UK) and the original Cox fuels (in the US) both used castor. Edited July 19, 2022 by brokenenglish Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted July 19, 2022 Share Posted July 19, 2022 It is indeed .074 and has a rear r/c carb. In the days of Nitrex 15 there was only castor available. Modern synthetic exceeds this with no gumming up. Quote Link to comment Share on other sites More sharing options...
gowen Posted July 19, 2022 Author Share Posted July 19, 2022 The listing described it as a "COX Queen Bee or QRC .049 glow engine". here is a photo. Quote Link to comment Share on other sites More sharing options...
PatMc Posted July 19, 2022 Share Posted July 19, 2022 (edited) It's a QRC 049. The Q means it has a silencer & RC usually that it has a larger capacity tank than those aimed at FF model market. You'll find it from this link > engine database > sort by order number > enter 4501. Edited July 19, 2022 by PatMc Quote Link to comment Share on other sites More sharing options...
PatMc Posted July 19, 2022 Share Posted July 19, 2022 (edited) BTW I had the same engine bought around the 1980's, I used it, mounted inverted, to power Henry a small motor glider. As related below & contrary to perceived wisdom the engine ran happily on straight (zero nitro) 80/20 fuel most of the time I owned it until I sold it. It was my habit to pop Henry in the car to have a few flights after flying my larger models, if the wind wasn't too strong. I generally used straight fuel (zero nitro) for the larger models & carried a small can of 10% nitro for Henry. As sod's law would have it one thermal promising day I got Henry out only to discover that I'd forgotten the 10% fuel can. With nothing to loose I filled Henry's tank with zero nitro fuel then was surprised when the little Cox started quite easily & ran well. There was little if any noticeable difference in the power so from then on the engine drank straight fuel. Henry in later life converted to a civilised power unit - 400 can motor with 7 nicads. Incidentally, I believe KK Nitrex 15 fuel didn't actually contain 15% nitromethane. IIRC, either Ron Waring or Peter Chinn wrote that it had about 5% nitromethane plus an unnamed substance that gave it the claimed equivalent of 15% nitromethane. The name was a marketing title. Edited July 19, 2022 by PatMc Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted July 19, 2022 Share Posted July 19, 2022 I was wondering about the perceived wisdom of high nitro requirement for these engines - ISTR running the Cox .049 on a power pod attached to my Graupner Amigo (perfect for full power touch and goes) on normal straight (castor) fuel back in the 70s - and I don’t recall any starting or running problems… Quote Link to comment Share on other sites More sharing options...
PatMc Posted July 19, 2022 Share Posted July 19, 2022 Martin, note that it also was no problem to start & run inverted. Just had to be careful not to over-prime. Quote Link to comment Share on other sites More sharing options...
Peter Christy Posted July 19, 2022 Share Posted July 19, 2022 Cox .049s don't need castor. I run mine on Bekra 16% Heli fuel, and they go like stink on it. Bekra is pure synthetic, around 18% from memory. Not had any issues running Coxs on it in over 10 years. -- Pete 1 Quote Link to comment Share on other sites More sharing options...
Don Fry Posted July 19, 2022 Share Posted July 19, 2022 2 hours ago, Martin Harris - Moderator said: I was wondering about the perceived wisdom of high nitro requirement for these engines - ISTR running the Cox .049 on a power pod attached to my Graupner Amigo (perfect for full power touch and goes) on normal straight (castor) fuel back in the 70s - and I don’t recall any starting or running problems… They will run on low nitromethane fuel. If the operator is capable of running it in a smaller window of success. It’s just easier to run it with a lot of nitromethane. Runs cooler, less fussy on the needle. Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted July 19, 2022 Share Posted July 19, 2022 Contact southern modelcraft. Dave will mix you some Cox fuel. You will either have to collect or arrange a courier to c9llect it as Dav3 doesn't post. He's at most shows though unless you really far up north. 1 Quote Link to comment Share on other sites More sharing options...
PatMc Posted July 19, 2022 Share Posted July 19, 2022 (edited) 2 hours ago, Don Fry said: They will run on low nitromethane fuel. If the operator is capable of running it in a smaller window of success. What's the heck's that supposed to mean ? Use the same start process as with high nitro fuel, adjust the needle in the same way & it works. Couldn't be easier. Edited July 19, 2022 by PatMc Quote Link to comment Share on other sites More sharing options...
J D 8 Posted July 19, 2022 Share Posted July 19, 2022 Cox Thimble-drome 049 happy on some 5% with a tad of castor. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted July 20, 2022 Share Posted July 20, 2022 Now if you are running a Cox Tee Dee series engine then nitro is vital to extract their full performance and revs. Cox own 'performance' fuel was 30%!! 1 Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted July 20, 2022 Share Posted July 20, 2022 I think the nitro content is something to do with the purity of the Methanol, I got 20 litres in the 70's from a chemist in Newcastle and mixed it with caster even my Cox .020 ran perfectly on it without any nitro. Quote Link to comment Share on other sites More sharing options...
Don Fry Posted July 20, 2022 Share Posted July 20, 2022 9 hours ago, PatMc said: What's the heck's that supposed to mean ? Use the same start process as with high nitro fuel, adjust the needle in the same way & it works. Couldn't be easier. I love you Pat. Needle valve settings are less critical with more nitromethane. Nitro methane also helps cooling. All a help if your ear, or experience is suboptimal. Quote Link to comment Share on other sites More sharing options...
Jason Channing Posted July 27, 2022 Share Posted July 27, 2022 On 18/07/2022 at 11:34, Andy Stephenson said: The fuel of choice for Cox engines back in the day was Nitrex 15. They seemed quite happy on this mixture, I'm not sure about the lubricant, it had 15% nitro which seemed enough. Fuel with 30% nitro needs an explosives licence in the UK and they are thinking of lowering it to 16%. I met a guy in the states who was using 45% nitro in his but this was excessive and unnecessary. Explosives precursor and poisons licence is what you need ,not an explosives license which is something totally different, very different in how they are acquired and renewed. The explosives license has a Firearms officer come and do an interview and the EPP is acquired though the Home Office. Both are relatively easy to acquire if you have nothing to hide. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.