J'EN 57 Engine

[Mike Bell]

Hi Danny, 1.5 turns on the needle sounds about right but it's what your ear tells you that counts. Regarding the piston failure, I have a theory about that. I reckon that the short run the engine had with the knocking big end could have initiated a fatigue crack around the gudgeon pin. This wouldn't have been noticeable when JE did the repairs but subsequently grew to destruction later. I'll never know for sure but I don't see any in-built weakness in the piston design.
I hope your engine stays clear of any probs as I would really like to see the J'en range get a good reputation. I like the idea of powerful good handling engines being that cheap!

[Danny Fenton]

Hi mike, the engine runs quite sweetly at 1.5 turns I was just concerned that the manual said 2 - 2.5 turns.
Fingers crossed on the big end.
Cheers

[Peter Roberts]

In response to the issues raised by Mike about conrods I emailed JE and asked for comments. I got the following back from Jenny.

"Hi Peter
Certainly the conrod on the J'en 56 and then 57 has been upgraded and strengthened from the early models. The J'en engines are under constant review and we try to bring improvements in as quickly as possible.
Regards, Jenny"

[Andrew le Roux]

Hi Peter

I've just read your post. I bought a Jen 57 when they first came out. I went through quiet a learning curve with the engine, mostly because it was my first non-OS. My experience with them was fit-and-forget, either because I was lucky or because of their quality.

To cut a long story short, I'm using Prosynth with 10 nitro in my Jen. Now that I know how the engine behaves, I have no issues with it at all. I do have to check the bottom end more than I'd like. I to tend to keep settings on the rich side, as there is no castor in the fuel.

I still think its excellent value for money and a great engine. I'm sure you'll get many years of excellent servivce from it.

[Peter Roberts]

Hi Andrew,
How absolutely amazing. My engines of preference prviously have been OS and my fuel was Duraglo but I converted to ProSynth after visiting Weston at a previous Sandown (alas) and was converted. It has been a good fuel. However. I asked JE to run the engine in and fitted it in place of an OS 46 on my Flair Kite - very ruggest plane. Took it to the field yesterday and had a lot of problems because the engine cut. Tried tuning the top end then bottom end all still the engine would run at a fairly afst tickover and after 40 secs running would just cut. I've spent a couple of hours today trying new plug, new fuel, and lots of tinkering with the settings. Re read Jenny's guidance and re ran it in. Seemed better for that. But given I had asked JE to run it in seems strange. My needle is currently set on 2 turns altho my 46 used to work best on 1½ turns.I'll keep trying. Rain stopped play today.

[Danny Fenton]

Finally flew my J'En 57 today, shed loads of power, pulled my Wot 4 around in a 25mph wind with no problems at all. A little fussy on the starting, it likes to be almost flooded, certainly very wet LOL The throttle response is good and it will sit at idle for a fair while and pick up fairly cleanly. As others have said this isn't an OS, but it certainly has power in excess. For the money I really cannot complain. Running mine on 5% nitro (Model Technics GX-5) One of the types recomended by Just Engines.

[Peter Roberts]

I'm pleased to say that the J'En 57 is running a treat. The bottom end needed to be a lot leaner to get it to pick up cleanly which I had been having problems with.

I've flow 5 or 6 times now and taken the main jet in a quarter turn at the end of this and she seems to respond nicely. I think that she'll get even better after a bit more running as there seems to be nothing left after three quarter throttle but up til that she's great. The tickover is sweet and low and starting is a dream.

It certainly seems to be great value so far and is pulling my Flair Kite into aerobatics much better than my OS 46 did. The Kite is quite a sturdy plane and is great as a trainer, general recovering of confidence, and if you think it can't do aerobatics think again. If you ever saw Paul heckles at ATS before he set up his own show - he'll show you aerobatics wiuth a kite. There are times when my general flying is glad that I have a sturdy plane. I'm a Kite fan. Its a lot stronger than a Wot4 - just takes a bit more building time.

[Danny Fenton]

Hi Peter interesting that you have added to your thread on the J'EN just when I am seeing a problem LOL I agree as the engine has become more run in the main needle has gone in a further 1/4 it now is happy at 1 1/4 out. the slow jet has been leaned a third and picks up cleanly. The idle is nice and it starts first or second flick if the plug is dripping with fuel. My problem however is that it will only run for 4 minutes at a time. I am still investigating why, it is not the fuel lines nor the tank or vents, nor the plug or overheating. I was suspicous of the pressure feed from the pipe to the tank as the nipple is very small. Peter are you using the standard or super quiet pipe? I am using the super quiet.

[Peter Roberts]

Danny - no I'm using the Genesis pipe which Weston made for my previous engine on this model which was an OS 46 AX and which however has the same size silencer mountings.

Is the 4 mins at a time on idle or is it whist in the air with you varying the throttle?

[Danny Fenton]

Hi Peter, in the air, its usually pootling about at 1/3 rd throttle. Until I have run another bench run, I wont know for sure, you know what it is like when you are flying, time passes quite quickly and my estimations may be totally wrong. I do know that when it stops it starts again first flick, (once on the ground) and the first occurence the tank still looked 7/8 full! I ran a subsequent flight with no cowling to ensure it wasn't overheating.

[Danny Fenton]

Hi Guys still no joy with the 57, the big end has gone the same way as others have mentioned, and a massive knocking developed. The engine is on its way back to Jenny and her team. I am dissapointed as the engine looks good and definitely has oodles of power. I so want them to be succesful because the work so hard for the customers. But at the end of the day I am not getting any flying in. I will let you know the outcome

[Peter Roberts]

Danny - what a tragic outcome. You know what Jenny's first question will be - what fuel have you been using? Are they going to replace it under warranty?

I'm furiously touching wood as mine is doing a great job on my Kite with oodles of power and making a great difference. Interested to see someone else using a OS 52 four stroke on the same plane - it certainly had a lot of low end power for take off.

Do let us know what Jenny says.

[Danny Fenton]

I have ALWAYS used the fuel specified by JE because of the forum, and people having trouble. I use Model Technics GX-5 which contains 20% castor, it is the recomended fuel. I never even tried a tank full of anything else. I am sure Jenny will sort out the problem

[Danny Fenton]

Hi Peter, finally cured the wot 4 of engine malladies, fitted an 800 watt leccy motor, no more deadsticks!

[Peter Roberts]

Now there's an interesting idea. Although I admit to having had a couple of dead sticks whilst getting used to battery life!

I've got a couple of electrics and will be interested to know how you get on. I converted a Black Horse Twister to electric, had all sorts of problems with it because I under spec'd the motor which promptly melted!

I then used a Hyperion 40 series (nice motor) and ESC which flew wonderfully but totalled it (due to pilot error) at speed so the Hyperion is now sitting happily in a Pulse XT which is really lovely.

The good thing about the Pulse XT is that it is fitted with mounts for either electric or ic, looks good and is great to handle.

I have to admit to being cautious now about doing leccy conversions. Will be interested to know how you get on with both the electrified Wot4 and Just Engine's repair of your J'EN.
mean while enjoy the Wot 4.

[Danny Fenton]

Hi Peter, The engine came back from Just Engines with the comment there is nothing wrong. I guess the end play in the big end is normal. The bad vibration at low revs was put down to the low end mixture being way too lean, which I do not understand as it would idle fine and pick up cleanly. I will try a different fuel as that is the common denominator. If I can be bothered to return to IC engines at all.
as for the Wot 4 it is transformed, you really cannot tell it is electric powered, it flies really well and is 1/2 lb lighter. I am using an 800 watt motor driving a 13 x 6.5 prop running on 6 x A123 cells. So far it peaks at about 40 amps but averages 10. The wot 4 is so slippery it flies on just third throttle, only needing more power for big loops and vertical manouvres. So far I limit flights to 8 minutes, but this is only draining 1400 mah of the 2300 pack. If you are considering this path go for it. A123 are charged using a cheap home design charger at 10 amps. Fully recharged after just 10-15 minutes in the plane, A123 don't explode LOL Here is the maiden flight, sorry for the file size and the idle chatter between my wife and I. Gives an idea of what can be achieved. Have had half a dozen flights since this was shot.
http://media.putfile.com/First-flight-electric-conversion-Wot-4

[Peter Roberts]

Fantastic Danny - looks a really neat conversion and flies so well. What a good evening for the flight.

Then other conversion thats impressive is how supportive your wife is. Great to see. Mine's supportive but would never want to be there. She's known for looking for the black plastic binsack full of bits and saying - well that was a waste of time wasn't it!

Great job Danny. Sorry at JE's response. However - I'm runningf my engine now on ProSynth and it runs well. I started off at 2 turns out and it has now after about 15 or 20 flights come in by a quarter of a turn.

Last Friday I had a mishap with one plane which ran into our long grass and ripped the undercart off my electric plane. The battery then got red hot and slightly puffy on one cell. However it has been tested, discharged and balanced since and I'll try it further on a low demand model.

I find with the J'EN 57 running an 11x7 prop that she comes in too fast on approach so am about to try it with a 12 x 6 and see if that gives some braking.

Congrats again on the Wot4 you never know David Ashby might want to do a feature!!

[Danny Fenton]

Hi Peter glad you found it interesting LOL We are organising a power fun fly later this month GreenacresMAC.co.uk and if I want to fly IC will need to get some fuel, I would like to try Prosynth, may try and get some at Weston Park. The wot 4 is my only "smelly" model
The conversion of the wot 4 has some hidden neat bits, the motor is mounted on lengths of studding attached to a ply mount, the mount itself has the same size holes as for the IC motor mount. undo four allen bolts, take the motor and mount off as one, bolt the IC mount back on and away you go. I have even left the throttle servo and snake in position. All that remains is to put the fuel tank in and remember to take the cells out! Sorry to hear about your arival and subsequent loss of undercarriage, puffy lipos, don't get that with A123 they are nigh on indestructible!

[Peter Roberts]

Hi Danny,
You'll find the Prosynth less messy I'm sure. Your mount sounds intruiging. Any change of acouple of photos showing it please?

I didn't think I would get puffy Lipos either - this is with a Flightpower one - scary (expensive) stuff.

[Danny Fenton]

Hi Peter, yes I have a flight power pack, doesn't deliver the C rating specified at all! I buy chinese ones now, $12 for a 1300 mah 30C and they work fine. Only use the lipos for up to 50" models though then the A123's come into there own. They are heavier than Lipos, but can deliver up to 120A (contrary to what you may read about these nano phosphate cells)
I will try and take some pics the next time the Wot 4 cowling is off so you can see. As they say a picture IS worth a thousand words LOL

[Danny Fenton]

Hi Peter I have put some pics in an album, if it worked LOL the album is titled Dannys models, it may take a little while for the pics to be authorised, as its after 5pm maybe a long while lol.

[Peter Roberts]

Thanks Danny - I'll look out for them. I've already circulated the link for the thread and your model flight around our club memebers so it should get a few hits.

[Danny Fenton]

Hi Peter the pics have gone live in the gallery. http://www.modelflying.co.uk/gallery/image.asp?sp=&v=5&uabn=218&uin=584 I think you can just about make out the 1/4 ply plate that carries the 4mm motor mounting studding. It has holes that locate over the IC motor mount holes. This means I can swap between the two in a matter of minutes.
Any questions let me know??