Thanks as always for the great service, thought I'd drop you a line to say my JEN .37 continues to give me great performance on its new purple pipe system. Before the pipe I used your 'quiet sliencer' and span a RAM 11 x 6 prop at 10,300 (nicely under the club's and BMFA's 82dB sound limit).

I've now fitted the pipe instead and I've gone up to a Bolly 11.5 x 6 prop. On first run (manifold not shortened, as supplied) with the addition of a 10mm exhaust port spacer I already had (to get clearance for my particular plane) the JEN matched exactly the 10,300 rpm on the new slightly bigger prop. I've now removed 10mm from the manifold and I'm getting 11,000 rpm and still down at 79dB. Seeing as the spacer added 10mm to the total exhaust length I've only really started at the standard length by taking off 10mm so I'll next be removing another 10mm to see if I can get any more out of it (which I expect I will).

Anyway, 11,000 rpm on an 11.5 x 6 is 40% more thrust than the orginal 10,300 rpm on an 11 x 6 by my calculation and I whilst I thought that sounded a bit wrong it certainly seems to be that way when its flying! Thanks!

As a footnote, a friend has an OS 46AX running the same Bolly 11.5 x 6 prop and he only gets 9,800 rpm and whilst you sell that engine for £109 the JEN .37 with the purple pipe is £20 cheaper and I suppose a fair bit lighter (and smaller) being a .25 size casing. I'll be buying another JEN .37 any time now to put my standard 'quiet sliencer' back to use in something new.

Les Pattison

I had a O.S. Max .25 (very good engine) in my Cambria fw109 and it struggled to get airborne from a hand launch (I finished the whole plane after the build with fibre glass very light fabric), hence the upgrade to your JEN .37 to make up the weight power ratio.

When this was hand launched with the JEN .37 I had to fly it by the seat of my pants, it was ballistic!!!, even at tick-over it passed by at 60mph.

The power of the engine was far to much. I have had set up on my ZHP9 W2 tranny and put in a throttle curve. I need the throttle curve so not to be forced into going past half throttle. I could not even trim out the plane even though it only had 4mm up and down movement (8mm in all) I had to really concentrate on flying it, so as not to trash it. It was an exhilarating experience to get it back to the patch to land it in one piece.

The power of the JEN .37 in a small plane is incredible, a war plane as you might know is very twitchy in large scale but small sizes amplify everything, but it gave me the biggest adrenalin rush imaginable, certainly for 2005. I have now calmed down the power, and will slowly increase the grunt as I get use to it. I can only say a 40" wingspan with a JEN .37 even the speed camera's would not be able to flash quick enough. Club members have said to me to enter the plane in our club speed trials. All the members who watched could not believe the power, let alone it landing in one piece.

Graham Hill

My JEN .37 has flown in one of Stan Yeo's Crazy Bats which originally flew very well on an SC .32. Using the JEN in the 'Splatbat' has given a big increase in the vertical performance using the same prop (9x6 Radio Active) as the .32. An underarm launch into a 30 degree climb progressing to an indefinite vertical climb out certainly draws attention. Speed is up and I expect the 9x7, to be fitted once the motor loosens off a little more, to up this again.

The motor remains easy to start, although it does like to be quite wet. With a little over an hours running in total it holds a rich peak readily and throttles crisply and reliably and runs right to the last few drops of fuel in the tank every time. I have tested the motor's toughness when the Splatbat got a bit ahead of my brain and fingers. It went into soft ground inverted at a reasonable speed. Testament to both engine and airframe that they flew again ten minutes later with a new prop. In summary, to date it seems like a real jem.

Stuart Doe

Just a quick email; the J'EN .37 purchased last week is now fitted in my limbo dancer and is superb, the throttle pipe looks, sounds and performs very nicely indeed. Thanks JE for the running in, made life easier.

S. Carr

I've always ran Leo .37's - but this J'EN IS impressive. 12,000 rpm, using an APC 11x6 on my Burley Pipe. Now that is a lot of thrust for a very small engine!

J. Cosford

Fitted the new J'EN .37 to my Limbo Dancer last week - far better than the .37 it replaced; more power and easier starting. So please send me a J'EN 56 to replace an aging XX .53 ;-)

Kieth Hotton

JEN 37 in Keith Hotton's Gangster 52 being held by a sadly un-named model

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