David Ovenden
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Posts posted by David Ovenden
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Well here's something to make you laugh.
Having spent some time making and fitting new tappet adjusting screws for my Enya 53-4C today I was looking in my engine spare parts box. There I found some parts from an old restoration of an Enya 40-4C. Guess what - I spotted a sealed packet with a genuine Enya tappet adjuster - the exact part number I needed. OK I did need 2 of them and only had 1 in stock - so I would still have had to make one anyway. But I should have looked properly first!
At least I now know that I have a spare one. Unless, of course, I forget again.
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Paul
I'll send you the details re repairs
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All good with the Saito. The repair was A1 and fast. The time-sert thread inserts are a "solid" insert not just a wire thread like "Helicoil" and they have a flange at the top for the glowplug to set against.
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43 minutes ago, Kim Taylor said:
Prices have got a bit salty recently, haven't they?
Alternatively, look at VQ kits at Sussex Model Centre (and others) and you'll find the same kit for £214.95.
You're welcome!!?
Kim
I think you will find that the VQ kit does not include the electric retracts nor the sprung oleo legs. The retracts are an extra. (About £95 I think)The Nexa kit does include the retracts. So you do need to compare like with like. SMC price is still attractive if they have stock left of course.
That said , yes all modelling goods (and just about all imported item) have seen very substantial increases recently as well as supply issues. The "cheap" days are never coming back I'm afraid!!
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Thanks Andy,
I count myself fortunate that it is only really the fuselage that needs attention (And one wing retaining plate where the screw pulled out.
This model does probably count as both the most interesting scale design I've built and at the same time the least successful flyer I have had. So I need to sort it out one way or another. I have seen other models (different designers and scales) flying happily on videos. The full-size aircraft carried thousands of passengers and was intrinsically sound. So my model's flying characteristics must be "fixable" surely?
I will strip all the covering from the fuselage to get it rebuilt straight. I can at that point double check all the rigging angles against the plan and the 3-view of the fullsize.
Whilst its not easy to reduce the weight of a finished model I could try a number of avenues. Firstly I could, as you say, use a single lipo pack. That however will mean drastic weight reduction at the rear to compensate. (A 4S 3700 pack is 380g) I used no ballast to get the correct CG so it can't be removed! I can remove the rudder and elevator servos from the tail end and move them right up to the nose and use closed loop controls for minimal weight at the back. Losing 60g at the rear is equal to 120g at the front as its a ratio of 2:1 in relation to the CG. Then add in the 60g of servos at the front we have a net improvement of 180g. It would still mean 200g of ballast weight up front If I drop to a single pack.
I could use foam wheels instead of the heavier Robart scale one that are fitted. I can remove the gyro and associated extra extension leads. The ESCs could possibly go right in the nose. Maybe I could replace the wiring to the motors with a lighter guage to save a gram or 2. Other than that it would be hard to lose much more weight without redesigning the whole model. Still, we will have a go. If it is possible to shave off 400g (one LiPo pack) without having to add extra balast to compensate it might make some difference, albeit with reduced flight times. Still, better a nice flying model with shorter duration than one with the potential for longer flights that doesn't get flown because of its unpleasant flying characteristics.
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Motion RC have them in stock.
Nexa is same as VQ. Includes retracts and oleos.
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Well Andy... a long time to reply. The Condor is not a pretty sight I'm afraid. The model has never felt "settled" and in the end it bit hard. It went into a terminal spin whilst flying straight and level and at a reasonable pace. I really don't know quite what prompted it. But once started, even though I had height, nothing would stop it ... till the ground did. Luckily the front of the fuselage acted as a crumple zone! In fact the wings , tail and rear fuselage are all OK.
I will rebuild the model over the winter and try adjusting the wing incidences whilst I'm at it. Then have another try next spring.
The model just never did feel right in the air from the beginning, so there must have been some underlying issue. Hopefully the rebuild will improve matters. Here's hoping anyway.
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Happy to witness the maiden flight this morning Paul. Model looked great against the blue sky.
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I now have 2 folding leg struts mostly completed knowing that the geometry works. I need to make up frames now to hold the retract unit and the rear strut pivot point so it can easily be mounted into the nacelle.
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Was out at the field this morning. Must have been too early to catch the flight. Or maybe I was too late?
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After bit of a break from the Bobcat project, I got some more done today. I have been doing some research into available materials and some experimenting with the design for the articulated oleo. I have finally decided on using some square aluminium tubing for the upper part of the strut. I fabricated some parts today to test the concept, which in general seems to work as planned. Video of the test on you tube here:
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Do you have a day planned for the maiden flight Paul?
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Well I think this topic has run now its course! It would be a shame if the thread ends up falling into the old elephant trap of "castor vs synthetic". I have made my decision and just need to get on with running the engine. Thanks for your all thoughts and ideas. I will report back once the engine has been run a bit.
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Warning of an imminent nostalgia moment!
I was reading an old magazine article about Vic Smeed, (the very famous designer, writer, editor etc.} It mentioned that he founded the Canterbury Pilgrims Model Flying Club (of which I was a member for many years} and that he opened a model shop in Canterbury after WWII . Though I lived near Canterbury and went to school in the town I am too young to remember anything of this shop. Does anyone have any knowledge or memories of the shop or where it was?
All the model shops in the town closed some years ago now. Though I don't remember Vic Smeed's shop, I do remember frequenting the following ones that did proper model supplies/rc models:
- Barretts toy/hobby department in St Geoges. Bought my first engine there- a DC Sabre (60s - 80s) Allegedly the shop had the biggest toy/hobby department outside of London??
- Canterbury Models in Butchery Lane. (An excellent shop before the great fire!)
- Northgate Models (handicrafts on the ground floor and models upstairs)
- Meers (Mostly industrial supplies but they opened model section for a brief while)
- Elite Models. (Bought a JR 10X radio from them in 2000)
Have I missed one?
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Thanks for all the replies I have received regarding the initial question. Given everything that has been contributed I will just use the standard Model Technics Laser 5% fuel that I have in stock.
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looking good Paul. Almost ready for the maiden flight. Next week.
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On 02/08/2021 at 06:49, Paul De Tourtoulon said:
Why the engine mouldings are originally painted black and the valve pushrods white I will never know !.
Black is the cheapest colour plastic they can get?
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Coming on nicely Paul. That Hellcat engine is excellent - is it going in the Sky raider?
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1 hour ago, Peter Christy said:
No! No! No! All that will do is varnish up the inside of the engine - especially if the engine is run hot. Modern synthetic fuels, as suggested by Jon, need no additives - especially not castor! All these rumours about "needing to add a little castor" date from decades ago when synthetic oils were in their infancy, and there were some very duff ones around. Modern synthetics are fine on their own, and need no help.
Say Hi to Tony for me! That Robot had the OS 15 in it, and is going up to Pontefract with me for the "retro" meet this week-end. Plans are still available for it, and I can thoroughly recommend it as one of the best trainers around!
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Pete
Pete,
I downloaded the Robot plan and just been having a look at it. I would want to change the 1/16" ply elevator though (that was intended for single channel use) to something more suitable for today. I would redesign a bit to make the elevator within the outline of the tailplane. The wing section is interesting. It says on the plan it is NACA 2412 but on the plan it shows the wing rib profile with a completely flat/straight line lower rear section and then a "flicked-up" trailing edge. (no doubt for ease of construction on the plan for novice builders) Might just redraw the rib to be really NACA 2412 profile, especially as the front of the rib has to be re-drawn anyway as the custom Veron LE profiled balsa isn't available . Still, will make a nice project.
Will say Hi to Tony for you
David
RE fuel. Well I don't have any castor oil in stock so it would be hard to add!
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1 hour ago, Jon - Laser Engines said:
This is an old article and while it relates to diesels the principals involved are the same for your enya. You can ignore the bit about extra oil and compression settings. I would also tend to use a smaller prop than normal not larger as combat diesels tend to use much smaller props than r/c would normally so the point of reference isnt the same. Something like a 7x5 or 6? I think i used to run my OS 15fp on 8x4 but it was run in by then.
Anyway have a read and see if you find any of it useful
https://web.archive.org/web/20190917165855/http://www3.telus.net/dieselcombat/about_diesels.htm
Again on fuel, my Enya 53, 120, 155 and 240 all run on laser 5 without issue. They are all 4 stroke but still, fuel is fuel.
Thanks Jon. I have had a read and will try out the "heat/cool/heat/repeat" technique when running in.
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3 minutes ago, Jon - Laser Engines said:
One thing i would suggest is you resist the temptation to run it slobbering rich. If it is a ferrous piston/liner you do need to get it hot or it wont work out too well. Its all about the expansion and work hardening, you need the heat. Dont thrash it as hard as an abc, but get the revs up and get some good heat into it. Say 90% of peak tune in short bursts.
On the fuel, i would use the laser 5 from the get go personally. A friend at my old club had a similar enya and we ran it from new on the laser 5 without any problems at all.
Thanks for the info Jon. I will avoid over-rich running and keep it hot. Good to know that Laser 5 fuel worked well in your friend's Enya.
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53 minutes ago, Engine Doctor said:
Hi David . You Enya has as you say old technology so won't develop as much power and heat as a modern engine . As its new then an oil rich fuel for running in is a good idea. A drop of castor added to your synthetic fuel should be OK for the Enya if it has iron piston and steel cylinder. A drop of castor may help prevent any scuffing during first runs. Once fully run in then synthetic should be OK. If its an ABC set up then synthetic from the first start.
I ran an old Enya 25 in a fun fighter some years ago on synthetic fuel . That had an iron piston and it was fine despite it being given a hard time .
One thing about Enya is they have the best quality materials so should be fine if run in correctly.
Thanks ED. I will probably just add a little castor to my normal fuel for the first few runs then revert to my usual synthetic fuel.
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1 hour ago, Peter Christy said:
One of my models has an OS15 of similar vintage in it. Runs fine on fully synthetic.
Indeed, I have quite a few old engines, my favourite being a Webra 61 that I bought in 1967. Despite having run on castor for decades, when brought out of retirement I switched it to full synthetic with no issues.
Castor belongs in a museum, not a model engine. A good synthetic is infinitely better.
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Pete
Thanks for the input Peter. I am seeing Tony H (one of your flying group) today and the purchase of this engine is partly to do with you both! He flew your old Veron Robot model recently and really liked it. I am helping him here in France with his electric model. I am wondering about building a "Robot-style" model for the Enya so he could get some flights in with it. Sort of retro-style training but with a buddy box!! I learnt to fly on my own in the 70s with a plan-build Radar model (quite like a Robot) fitted with an Enya 15 and HB kit-build radio.
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Firstly, just to be clear, this post is NOT about what is the best fuel for model engines.
I have acquired an Enya 15-IV engine. This engine was produced I guess in the early 70's. So it has old technology and metallurgy. However, it has never been used , mounted or seen fuel. So it needs running-in from scratch. I use nothing but fully synthetic fuel in all my engines (nearly always Prosynth 10% but I do have some Model Technics Laser 5% too) Most of the forum posts I have seen (mostly US-based) talk about only using castor based fuel (with at least 20% castor) with these old cast iron, steel liner Enyas. However Engine Doctor on an old post on this forum hinted that while that might be the correct policy for old engine that previously ran on castor based fuel, it may not apply to unrun "old" engines.
So my question is:
Do I run this unused Enya 15-IV engine on modern synthetic fuel right from the start? Or, might it be wise to add some extra castor oil to my Laser 5% fuel for the running in period and then revert to standard synthetic oil fuel. Or do I need to (against all my instincts) get hold some Castor based fuel and use that just for this old Enya? Or something different ?
I am interested in your thoughts about this specific engine and the right fuel for it. Please don't get into general debate about castor vs synthetic. Its been done to death, and just causes "overheating" and "friction" on the forum which is the opposite of what any good lubricant should do!!
Making a tappet adjusting screw?
in IC Engines
Posted
3/8" = 9.52mm = .38 inch
7/8" = 22.2mm = .88 inch
9/32" = 7.14mm = .28 inch