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Diesel Wot4 foam-e

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scott finnie20/06/2013 01:30:49
756 forum posts
95 photos

Hi ,

i'm wanting try out a diesel engine aircraft. I have nominated my wot4 foam-e, what size diesel do you all recommend? I'm not after aerobatic performance and prop hangs ect id rather a nice scale looking and sounding flight, i dont want to be really underpowered and struggling but rather in the middle,

Any help will be greatly appreciated and a big thanks for all who help me achieve this goal,

also any info on diesel engines and how they work too, no tools ect to start engine? can you use petrol station diesel?

Yeap im a noob when it comes to diesel haha



Frank Skilbeck20/06/2013 10:48:47
4819 forum posts
107 photos

Model diesel is nothing like car diesel as you can see on the Model Technics website. I'm not sure if foam is compatible with consitiuents of model diesel fuel.

Have a look on the PAW website for info on diesels

Bob Cotsford20/06/2013 10:58:13
8749 forum posts
489 photos

paraffin, ether and oil are the basic ingredients with a small percentage of additives in some fuels. I wouldn't have thought it would attack EPO foam, but best to check first. For a FoamE I'd have thought a PAW 19D would be about right.

Quite simply a diesel is just like your glow engines, except that the fuel used is paraffin and it contains ether as an igniter. There's no external power supply, no glowplug, no sparkplug, but what it does have is a second piston upside down in the cylinder head. A screw on top of the head can push this piston down to adjust the compression ratio, so what you have in effect is a variable height cylinder head.

The compression is usually higher than a glow motor, and the heat generated by compressing the fuel charge is enough to ignite the ether in the fuel, which in turn burns the paraffin giving you the power. Diesels typically use less fuel than a comparable sized glow, but also run at lower revs turning larger props.

Bob Cotsford20/06/2013 11:04:30
8749 forum posts
489 photos

Because diesels like to start wet and have a higher compression ratio, it's easy to flood the cylinder head resulting in 'hydraulic lock' - the space above the piston gets filled with fuel which won't compress so the engine can't turn over. If you are using an electric starter it can easily bend the conrod or worse as it insists on turning the prop so diesels are normally hand started. Clearing a hydraulic lock is just a matter of holding the engine on it's side and turning the prop back and forth until the excess fuel drains out of the exhaust.

Go for it, it will demonstrate why 99% of IC modellers use glow or spark motorswink

Simon Chambers20/06/2013 11:11:46
789 forum posts
42 photos

You might be better off going for the Wot4e (i.e. the wood electric version). I belive its discontinued, but you may find a retailer around who is selling one off.


Steve Hargreaves - Moderator20/06/2013 12:25:48
6765 forum posts
197 photos

Sounds like great fun.....teeth 2

I can't add much to what the others have said here but I'd love to know how you get on.....

Remember to use a bigger prop on a makes them easier to start....Bobs idea of a PAW19 sounds about right to me.....I'd fit an 11 x 5 to that motor.....ebay might turn up a good used example...or you can buy new obviously....try & get one with a muffler/collector exhaust diesels are very noisy & spray gunk least with a muffler you can direct some of the crud away from the model.....wink 2

Oh & make sure you can source the fuel too....I don't think it can be sent through the post so you may find that your LMS will need to stock it. Model Technics D1000 ot D2000 should do the job.....Southern Modelcraft can supply Diesel fuel too but this is generally only available at the shows....

scott finnie20/06/2013 13:04:08
756 forum posts
95 photos

Hi guys,

Thanks for all the advice, ive started bidding on a PAW19 on ebay so fingers crossed, i have an 11x5 maple prop handy too! I'll pop along to Literally Scotlands only LMS and see about Diesel fuel, im also going to fit larger wheels so that the bumps from my field dont restrict take-off speed too much! I have the wot4e and love it alot, still got a few nitro aircraft but ive always been curious of diesel power, I'll keep this post upto date with my progress , cant do too much till i hopefully win this engine, fingers crossed!



Braddock, VC20/06/2013 14:06:20
1657 forum posts
82 photos

You'll probably regret it, the amount of black gunge that comes out of the exhaust is incredible. I learned to fly on a junior 60 with an irvine 20 diesel, I took the head off and fitted the glow one that was supplied and threw the head away.

If my wot4 foam e is anything to go by it doesn't look as though it would stand the conversion but I wish you luck. Try googling Davies Diesel Conversions, they make the cylinder heads for virtually all glow engines to convert them to compression ignition, quite cheap as I recall, I think just engines stocked them at one stage.

Steve Hargreaves - Moderator20/06/2013 14:17:01
6765 forum posts
197 photos

Certainly you will need to modify the front end to take an engine mount.....I don't have a Wot 4 foamie so I can't comment but do make sure you have a solid & secure mounting for the engine......IC equals oil & vibration....especially when its a think this through carefully & ask "someone who knows" if unsure....

Good luck.....thumbs up

Former Member20/06/2013 20:31:25

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Former Member20/06/2013 20:41:16

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Chris Bott - Moderator20/06/2013 21:25:33
6843 forum posts
1429 photos
1 articles

Scott you will very likely need to beef up the engine mount area of a foamie, a diesel can really snatch if you give it a good flick and get a hydraulic lock.

Oh and did someone mention the mess?

dsc_1025 (1280x850).jpg

I'll be really interested to know how you get on though

Turbycat20/06/2013 21:41:09
594 forum posts
55 photos

I wouldn't bother putting a diesel on a foamie. One good flick and the nose wil come off! Build or buy a secondhand vintage style airframe for it. I've only used diesels on control line but they were powerful little lumps!


Robin Kearney20/06/2013 23:25:55
1081 forum posts
183 photos

Chris that's not mess, rather it is the source of a lovely smell!

Sounds like a fun thing to try Scott, I love my diesels. I think somebody on here out a 10cc paw in the front of an ARTF Acro Wot.

If you do get that PAW and you have any troubles with it, ring the guys at the factory, they are always very helpful. They sorted out a few bits and pieces for an old 1.49 I have. Great service.

scott finnie21/06/2013 00:54:25
756 forum posts
95 photos

I will be proceeding with this conversion, i will be beefing up the engine mount, i have lots of spare ply and carbon rods, will create something beefy i hope, i only want one diesel aircraft at the moment , fallen in love with the sound and easy-ish starting without glow-stick ect , slightly longer flight times and a scale flight , hopefully get this PAW and find out what the small diesel world is like, ive taken a firm note of all recommendations from here and all advice, will have an onboard camera for maiden too so if it doesnt fly you will all know, the most genuine way of trying knew things me thinks,



Martin Harris21/06/2013 09:35:10
9502 forum posts
256 photos

Funnily enough I flew my first diesel for over 40 years yesterday (although strictly speaking our glow engines are diesels) after seeing some control lines and handles going cheap in the Micron "closing down" sale.

I found the plans for a KK Phantom Mite on the 'net and knocked one up for a DC Merlin that's been lurking around my modelling room for many years, to reproduce my last experiences with C/L. A few flicks later and some tweaking of needle and compression lever and away it went...amazing performance for 0.76 cc (that's 0.047 cubic inches in glow terms) swinging a massive 6 x 4 prop.

Great fun and oohhhh......the wonderful aroma of burnt diesel fuel! So much more practical than electric power - just a pint can of fuel and you could fly all day!

And I didn't feel at all dizzy until I landed it.

Foxfan10/07/2013 13:34:57
931 forum posts
7 photos

Diesels are great! I had a PAW 19 on a huge model microlight. It took off and went up like rocket. I thought I'd lost it and then mercifully the screamer stopped and down it came in big swooping circuits till it landed on its tricycle. My first ever R/C flght. And then I repeated it!

I still sometimes run my old childhood ED Racer just fo fun. When I was akid I ran it bolted to the coal bunker just for the wonderful smell.

So what if they're dirty...that's what fuel proofer's for. You'll never need another smelly thing in the car!

PAW are terrific engines and British!

You can even make your own fuel as we used to, courtesy of a friendly chemist. But then in those days it wasn't expensive. I used to often be seen with a tin of Nitrex 15 in me pocket!

Good luck.


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